const char parsers_rcs[] = "$Id: parsers.c,v 1.284 2014/02/10 14:42:42 fabiankeil Exp $"; /********************************************************************* * * File : $Source: /cvsroot/ijbswa/current/parsers.c,v $ * * Purpose : Declares functions to parse/crunch headers and pages. * * Copyright : Written by and Copyright (C) 2001-2012 the * Privoxy team. http://www.privoxy.org/ * * Based on the Internet Junkbuster originally written * by and Copyright (C) 1997 Anonymous Coders and * Junkbusters Corporation. http://www.junkbusters.com * * This program is free software; you can redistribute it * and/or modify it under the terms of the GNU General * Public License as published by the Free Software * Foundation; either version 2 of the License, or (at * your option) any later version. * * This program is distributed in the hope that it will * be useful, but WITHOUT ANY WARRANTY; without even the * implied warranty of MERCHANTABILITY or FITNESS FOR A * PARTICULAR PURPOSE. See the GNU General Public * License for more details. * * The GNU General Public License should be included with * this file. If not, you can view it at * http://www.gnu.org/copyleft/gpl.html * or write to the Free Software Foundation, Inc., 59 * Temple Place - Suite 330, Boston, MA 02111-1307, USA. * *********************************************************************/ #include "config.h" #ifndef _WIN32 #include #include #endif #include #include #include #include #ifdef __GLIBC__ /* * Convince GNU's libc to provide a strptime prototype. */ #define __USE_XOPEN #endif /*__GLIBC__ */ #include #ifdef FEATURE_ZLIB #include #define GZIP_IDENTIFIER_1 0x1f #define GZIP_IDENTIFIER_2 0x8b #define GZIP_FLAG_CHECKSUM 0x02 #define GZIP_FLAG_EXTRA_FIELDS 0x04 #define GZIP_FLAG_FILE_NAME 0x08 #define GZIP_FLAG_COMMENT 0x10 #define GZIP_FLAG_RESERVED_BITS 0xe0 #endif #if !defined(_WIN32) && !defined(__OS2__) #include #endif #include "project.h" #ifdef FEATURE_PTHREAD #include "jcc.h" /* jcc.h is for mutex semapores only */ #endif /* def FEATURE_PTHREAD */ #include "list.h" #include "parsers.h" #include "ssplit.h" #include "errlog.h" #include "jbsockets.h" #include "miscutil.h" #include "list.h" #include "actions.h" #include "filters.h" #ifndef HAVE_STRPTIME #include "strptime.h" #endif const char parsers_h_rcs[] = PARSERS_H_VERSION; static char *get_header_line(struct iob *iob); static jb_err scan_headers(struct client_state *csp); static jb_err header_tagger(struct client_state *csp, char *header); static jb_err parse_header_time(const char *header_time, time_t *result); static jb_err crumble (struct client_state *csp, char **header); static jb_err filter_header (struct client_state *csp, char **header); static jb_err client_connection (struct client_state *csp, char **header); static jb_err client_referrer (struct client_state *csp, char **header); static jb_err client_uagent (struct client_state *csp, char **header); static jb_err client_ua (struct client_state *csp, char **header); static jb_err client_from (struct client_state *csp, char **header); static jb_err client_send_cookie (struct client_state *csp, char **header); static jb_err client_x_forwarded (struct client_state *csp, char **header); static jb_err client_accept_encoding (struct client_state *csp, char **header); static jb_err client_te (struct client_state *csp, char **header); static jb_err client_max_forwards (struct client_state *csp, char **header); static jb_err client_host (struct client_state *csp, char **header); static jb_err client_if_modified_since (struct client_state *csp, char **header); static jb_err client_accept_language (struct client_state *csp, char **header); static jb_err client_if_none_match (struct client_state *csp, char **header); static jb_err crunch_client_header (struct client_state *csp, char **header); static jb_err client_x_filter (struct client_state *csp, char **header); static jb_err client_range (struct client_state *csp, char **header); static jb_err server_set_cookie (struct client_state *csp, char **header); static jb_err server_connection (struct client_state *csp, char **header); static jb_err server_content_type (struct client_state *csp, char **header); static jb_err server_adjust_content_length(struct client_state *csp, char **header); static jb_err server_content_md5 (struct client_state *csp, char **header); static jb_err server_content_encoding (struct client_state *csp, char **header); static jb_err server_transfer_coding (struct client_state *csp, char **header); static jb_err server_http (struct client_state *csp, char **header); static jb_err crunch_server_header (struct client_state *csp, char **header); static jb_err server_last_modified (struct client_state *csp, char **header); static jb_err server_content_disposition(struct client_state *csp, char **header); #ifdef FEATURE_ZLIB static jb_err server_adjust_content_encoding(struct client_state *csp, char **header); #endif #ifdef FEATURE_CONNECTION_KEEP_ALIVE static jb_err server_save_content_length(struct client_state *csp, char **header); static jb_err server_keep_alive(struct client_state *csp, char **header); static jb_err server_proxy_connection(struct client_state *csp, char **header); static jb_err client_keep_alive(struct client_state *csp, char **header); static jb_err client_save_content_length(struct client_state *csp, char **header); static jb_err client_proxy_connection(struct client_state *csp, char **header); #endif /* def FEATURE_CONNECTION_KEEP_ALIVE */ static jb_err client_host_adder (struct client_state *csp); static jb_err client_xtra_adder (struct client_state *csp); static jb_err client_x_forwarded_for_adder(struct client_state *csp); static jb_err client_connection_header_adder(struct client_state *csp); static jb_err server_connection_adder(struct client_state *csp); #ifdef FEATURE_CONNECTION_KEEP_ALIVE static jb_err server_proxy_connection_adder(struct client_state *csp); #endif /* def FEATURE_CONNECTION_KEEP_ALIVE */ static jb_err proxy_authentication(struct client_state *csp, char **header); static jb_err create_forged_referrer(char **header, const char *hostport); static jb_err create_fake_referrer(char **header, const char *fake_referrer); static jb_err handle_conditional_hide_referrer_parameter(char **header, const char *host, const int parameter_conditional_block); static void create_content_length_header(unsigned long long content_length, char *header, size_t buffer_length); /* * List of functions to run on a list of headers. */ struct parsers { /** The header prefix to match */ const char *str; /** The length of the prefix to match */ const size_t len; /** The function to apply to this line */ const parser_func_ptr parser; }; static const struct parsers client_patterns[] = { { "referer:", 8, client_referrer }, { "user-agent:", 11, client_uagent }, { "ua-", 3, client_ua }, { "from:", 5, client_from }, { "cookie:", 7, client_send_cookie }, { "x-forwarded-for:", 16, client_x_forwarded }, { "Accept-Encoding:", 16, client_accept_encoding }, { "TE:", 3, client_te }, { "Host:", 5, client_host }, { "if-modified-since:", 18, client_if_modified_since }, #ifdef FEATURE_CONNECTION_KEEP_ALIVE { "Keep-Alive:", 11, client_keep_alive }, { "Content-Length:", 15, client_save_content_length }, { "Proxy-Connection:", 17, client_proxy_connection }, #else { "Keep-Alive:", 11, crumble }, { "Proxy-Connection:", 17, crumble }, #endif { "connection:", 11, client_connection }, { "max-forwards:", 13, client_max_forwards }, { "Accept-Language:", 16, client_accept_language }, { "if-none-match:", 14, client_if_none_match }, { "Range:", 6, client_range }, { "Request-Range:", 14, client_range }, { "If-Range:", 9, client_range }, { "X-Filter:", 9, client_x_filter }, { "Proxy-Authorization:", 20, proxy_authentication }, #if 0 { "Transfer-Encoding:", 18, client_transfer_encoding }, #endif { "*", 0, crunch_client_header }, { "*", 0, filter_header }, { NULL, 0, NULL } }; static const struct parsers server_patterns[] = { { "HTTP/", 5, server_http }, { "set-cookie:", 11, server_set_cookie }, { "connection:", 11, server_connection }, { "Content-Type:", 13, server_content_type }, { "Content-MD5:", 12, server_content_md5 }, { "Content-Encoding:", 17, server_content_encoding }, #ifdef FEATURE_CONNECTION_KEEP_ALIVE { "Content-Length:", 15, server_save_content_length }, { "Keep-Alive:", 11, server_keep_alive }, { "Proxy-Connection:", 17, server_proxy_connection }, #else { "Keep-Alive:", 11, crumble }, #endif /* def FEATURE_CONNECTION_KEEP_ALIVE */ { "Transfer-Encoding:", 18, server_transfer_coding }, { "content-disposition:", 20, server_content_disposition }, { "Last-Modified:", 14, server_last_modified }, { "Proxy-Authenticate:", 19, proxy_authentication }, { "*", 0, crunch_server_header }, { "*", 0, filter_header }, { NULL, 0, NULL } }; static const add_header_func_ptr add_client_headers[] = { client_host_adder, client_x_forwarded_for_adder, client_xtra_adder, client_connection_header_adder, NULL }; static const add_header_func_ptr add_server_headers[] = { server_connection_adder, #ifdef FEATURE_CONNECTION_KEEP_ALIVE server_proxy_connection_adder, #endif /* def FEATURE_CONNECTION_KEEP_ALIVE */ NULL }; /********************************************************************* * * Function : flush_socket * * Description : Write any pending "buffered" content. * * Parameters : * 1 : fd = file descriptor of the socket to read * 2 : iob = The I/O buffer to flush, usually csp->iob. * * Returns : On success, the number of bytes written are returned (zero * indicates nothing was written). On error, -1 is returned, * and errno is set appropriately. If count is zero and the * file descriptor refers to a regular file, 0 will be * returned without causing any other effect. For a special * file, the results are not portable. * *********************************************************************/ long flush_socket(jb_socket fd, struct iob *iob) { long len = iob->eod - iob->cur; if (len <= 0) { return(0); } if (write_socket(fd, iob->cur, (size_t)len)) { return(-1); } iob->eod = iob->cur = iob->buf; return(len); } /********************************************************************* * * Function : add_to_iob * * Description : Add content to the buffer, expanding the * buffer if necessary. * * Parameters : * 1 : iob = Destination buffer. * 2 : buffer_limit = Limit to which the destination may grow * 3 : src = holds the content to be added * 4 : n = number of bytes to be added * * Returns : JB_ERR_OK on success, JB_ERR_MEMORY if out-of-memory * or buffer limit reached. * *********************************************************************/ jb_err add_to_iob(struct iob *iob, const size_t buffer_limit, char *src, long n) { size_t used, offset, need; char *p; if (n <= 0) return JB_ERR_OK; used = (size_t)(iob->eod - iob->buf); offset = (size_t)(iob->cur - iob->buf); need = used + (size_t)n + 1; /* * If the buffer can't hold the new data, extend it first. * Use the next power of two if possible, else use the actual need. */ if (need > buffer_limit) { log_error(LOG_LEVEL_INFO, "Buffer limit reached while extending the buffer (iob). Needed: %d. Limit: %d", need, buffer_limit); return JB_ERR_MEMORY; } if (need > iob->size) { size_t want = iob->size ? iob->size : 512; while (want <= need) { want *= 2; } if (want <= buffer_limit && NULL != (p = (char *)realloc(iob->buf, want))) { iob->size = want; } else if (NULL != (p = (char *)realloc(iob->buf, need))) { iob->size = need; } else { log_error(LOG_LEVEL_ERROR, "Extending the buffer (iob) failed: %E"); return JB_ERR_MEMORY; } /* Update the iob pointers */ iob->cur = p + offset; iob->eod = p + used; iob->buf = p; } /* copy the new data into the iob buffer */ memcpy(iob->eod, src, (size_t)n); /* point to the end of the data */ iob->eod += n; /* null terminate == cheap insurance */ *iob->eod = '\0'; return JB_ERR_OK; } /********************************************************************* * * Function : clear_iob * * Description : Frees the memory allocated for an I/O buffer and * resets the structure. * * Parameters : * 1 : iob = I/O buffer to clear. * * Returns : JB_ERR_OK on success, JB_ERR_MEMORY if out-of-memory * or buffer limit reached. * *********************************************************************/ void clear_iob(struct iob *iob) { free(iob->buf); memset(iob, '\0', sizeof(*iob));; } #ifdef FEATURE_ZLIB /********************************************************************* * * Function : decompress_iob * * Description : Decompress buffered page, expanding the * buffer as necessary. csp->iob->cur * should point to the the beginning of the * compressed data block. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : JB_ERR_OK on success, * JB_ERR_MEMORY if out-of-memory limit reached, and * JB_ERR_COMPRESS if error decompressing buffer. * *********************************************************************/ jb_err decompress_iob(struct client_state *csp) { char *buf; /* new, uncompressed buffer */ char *cur; /* Current iob position (to keep the original * iob->cur unmodified if we return early) */ size_t bufsize; /* allocated size of the new buffer */ size_t old_size; /* Content size before decompression */ size_t skip_size; /* Number of bytes at the beginning of the iob that we should NOT decompress. */ int status; /* return status of the inflate() call */ z_stream zstr; /* used by calls to zlib */ assert(csp->iob->cur - csp->iob->buf > 0); assert(csp->iob->eod - csp->iob->cur > 0); bufsize = csp->iob->size; skip_size = (size_t)(csp->iob->cur - csp->iob->buf); old_size = (size_t)(csp->iob->eod - csp->iob->cur); cur = csp->iob->cur; if (bufsize < (size_t)10) { /* * This is to protect the parsing of gzipped data, * but it should(?) be valid for deflated data also. */ log_error(LOG_LEVEL_ERROR, "Buffer too small decompressing iob"); return JB_ERR_COMPRESS; } if (csp->content_type & CT_GZIP) { /* * Our task is slightly complicated by the facts that data * compressed by gzip does not include a zlib header, and * that there is no easily accessible interface in zlib to * handle a gzip header. We strip off the gzip header by * hand, and later inform zlib not to expect a header. */ /* * Strip off the gzip header. Please see RFC 1952 for more * explanation of the appropriate fields. */ if (((*cur++ & 0xff) != GZIP_IDENTIFIER_1) || ((*cur++ & 0xff) != GZIP_IDENTIFIER_2) || (*cur++ != Z_DEFLATED)) { log_error(LOG_LEVEL_ERROR, "Invalid gzip header when decompressing"); return JB_ERR_COMPRESS; } else { int flags = *cur++; if (flags & GZIP_FLAG_RESERVED_BITS) { /* The gzip header has reserved bits set; bail out. */ log_error(LOG_LEVEL_ERROR, "Invalid gzip header flags when decompressing"); return JB_ERR_COMPRESS; } /* * Skip mtime (4 bytes), extra flags (1 byte) * and OS type (1 byte). */ cur += 6; /* Skip extra fields if necessary. */ if (flags & GZIP_FLAG_EXTRA_FIELDS) { /* * Skip a given number of bytes, specified * as a 16-bit little-endian value. * * XXX: this code is untested and should probably be removed. */ int skip_bytes; skip_bytes = *cur++; skip_bytes += *cur++ << 8; /* * The number of bytes to skip should be positive * and we'd like to stay in the buffer. */ if ((skip_bytes < 0) || (skip_bytes >= (csp->iob->eod - cur))) { log_error(LOG_LEVEL_ERROR, "Unreasonable amount of bytes to skip (%d). Stopping decompression", skip_bytes); return JB_ERR_COMPRESS; } log_error(LOG_LEVEL_INFO, "Skipping %d bytes for gzip compression. Does this sound right?", skip_bytes); cur += skip_bytes; } /* Skip the filename if necessary. */ if (flags & GZIP_FLAG_FILE_NAME) { /* A null-terminated string is supposed to follow. */ while (*cur++ && (cur < csp->iob->eod)); } /* Skip the comment if necessary. */ if (flags & GZIP_FLAG_COMMENT) { /* A null-terminated string is supposed to follow. */ while (*cur++ && (cur < csp->iob->eod)); } /* Skip the CRC if necessary. */ if (flags & GZIP_FLAG_CHECKSUM) { cur += 2; } if (cur >= csp->iob->eod) { /* * If the current position pointer reached or passed * the buffer end, we were obviously tricked to skip * too much. */ log_error(LOG_LEVEL_ERROR, "Malformed gzip header detected. Aborting decompression."); return JB_ERR_COMPRESS; } } } else if (csp->content_type & CT_DEFLATE) { /* * In theory (that is, according to RFC 1950), deflate-compressed * data should begin with a two-byte zlib header and have an * adler32 checksum at the end. It seems that in practice only * the raw compressed data is sent. Note that this means that * we are not RFC 1950-compliant here, but the advantage is that * this actually works. :) * * We add a dummy null byte to tell zlib where the data ends, * and later inform it not to expect a header. * * Fortunately, add_to_iob() has thoughtfully null-terminated * the buffer; we can just increment the end pointer to include * the dummy byte. */ csp->iob->eod++; } else { log_error(LOG_LEVEL_ERROR, "Unable to determine compression format for decompression"); return JB_ERR_COMPRESS; } /* Set up the fields required by zlib. */ zstr.next_in = (Bytef *)cur; zstr.avail_in = (unsigned int)(csp->iob->eod - cur); zstr.zalloc = Z_NULL; zstr.zfree = Z_NULL; zstr.opaque = Z_NULL; /* * Passing -MAX_WBITS to inflateInit2 tells the library * that there is no zlib header. */ if (inflateInit2(&zstr, -MAX_WBITS) != Z_OK) { log_error(LOG_LEVEL_ERROR, "Error initializing decompression"); return JB_ERR_COMPRESS; } /* * Next, we allocate new storage for the inflated data. * We don't modify the existing iob yet, so in case there * is error in decompression we can recover gracefully. */ buf = zalloc(bufsize); if (NULL == buf) { log_error(LOG_LEVEL_ERROR, "Out of memory decompressing iob"); return JB_ERR_MEMORY; } assert(bufsize >= skip_size); memcpy(buf, csp->iob->buf, skip_size); zstr.avail_out = (uInt)(bufsize - skip_size); zstr.next_out = (Bytef *)buf + skip_size; /* Try to decompress the whole stream in one shot. */ while (Z_BUF_ERROR == (status = inflate(&zstr, Z_FINISH))) { /* We need to allocate more memory for the output buffer. */ char *tmpbuf; /* used for realloc'ing the buffer */ size_t oldbufsize = bufsize; /* keep track of the old bufsize */ if (0 == zstr.avail_in) { /* * If zlib wants more data then there's a problem, because * the complete compressed file should have been buffered. */ log_error(LOG_LEVEL_ERROR, "Unexpected end of compressed iob. Using what we got so far."); break; } /* * If we reached the buffer limit and still didn't have enough * memory, just give up. Due to the ceiling enforced by the next * if block we could actually check for equality here, but as it * can be easily mistaken for a bug we don't. */ if (bufsize >= csp->config->buffer_limit) { log_error(LOG_LEVEL_ERROR, "Buffer limit reached while decompressing iob"); return JB_ERR_MEMORY; } /* Try doubling the buffer size each time. */ bufsize *= 2; /* Don't exceed the buffer limit. */ if (bufsize > csp->config->buffer_limit) { bufsize = csp->config->buffer_limit; } /* Try to allocate the new buffer. */ tmpbuf = realloc(buf, bufsize); if (NULL == tmpbuf) { log_error(LOG_LEVEL_ERROR, "Out of memory decompressing iob"); freez(buf); return JB_ERR_MEMORY; } else { char *oldnext_out = (char *)zstr.next_out; /* * Update the fields for inflate() to use the new * buffer, which may be in a location different from * the old one. */ zstr.avail_out += (uInt)(bufsize - oldbufsize); zstr.next_out = (Bytef *)tmpbuf + bufsize - zstr.avail_out; /* * Compare with an uglier method of calculating these values * that doesn't require the extra oldbufsize variable. */ assert(zstr.avail_out == tmpbuf + bufsize - (char *)zstr.next_out); assert((char *)zstr.next_out == tmpbuf + ((char *)oldnext_out - buf)); buf = tmpbuf; } } if (Z_STREAM_ERROR == inflateEnd(&zstr)) { log_error(LOG_LEVEL_ERROR, "Inconsistent stream state after decompression: %s", zstr.msg); /* * XXX: Intentionally no return. * * According to zlib.h, Z_STREAM_ERROR is returned * "if the stream state was inconsistent". * * I assume in this case inflate()'s status * would also be something different than Z_STREAM_END * so this check should be redundant, but lets see. */ } if ((status != Z_STREAM_END) && (0 != zstr.avail_in)) { /* * We failed to decompress the stream and it's * not simply because of missing data. */ log_error(LOG_LEVEL_ERROR, "Unexpected error while decompressing to the buffer (iob): %s", zstr.msg); return JB_ERR_COMPRESS; } /* * Finally, we can actually update the iob, since the * decompression was successful. First, free the old * buffer. */ freez(csp->iob->buf); /* Now, update the iob to use the new buffer. */ csp->iob->buf = buf; csp->iob->cur = csp->iob->buf + skip_size; csp->iob->eod = (char *)zstr.next_out; csp->iob->size = bufsize; /* * Make sure the new uncompressed iob obeys some minimal * consistency conditions. */ if ((csp->iob->buf < csp->iob->cur) && (csp->iob->cur <= csp->iob->eod) && (csp->iob->eod <= csp->iob->buf + csp->iob->size)) { const size_t new_size = (size_t)(csp->iob->eod - csp->iob->cur); if (new_size > (size_t)0) { log_error(LOG_LEVEL_RE_FILTER, "Decompression successful. Old size: %d, new size: %d.", old_size, new_size); } else { /* zlib thinks this is OK, so lets do the same. */ log_error(LOG_LEVEL_INFO, "Decompression didn't result in any content."); } } else { /* It seems that zlib did something weird. */ log_error(LOG_LEVEL_ERROR, "Unexpected error decompressing the buffer (iob): %d==%d, %d>%d, %d<%d", csp->iob->cur, csp->iob->buf + skip_size, csp->iob->eod, csp->iob->buf, csp->iob->eod, csp->iob->buf + csp->iob->size); return JB_ERR_COMPRESS; } return JB_ERR_OK; } #endif /* defined(FEATURE_ZLIB) */ /********************************************************************* * * Function : normalize_lws * * Description : Reduces unquoted linear white space in headers * to a single space in accordance with RFC 2616 2.2. * This simplifies parsing and filtering later on. * * XXX: Remove log messages before * the next stable release? * * Parameters : * 1 : header = A header with linear white space to reduce. * * Returns : N/A * *********************************************************************/ static void normalize_lws(char *header) { char *p = header; while (*p != '\0') { if (privoxy_isspace(*p) && privoxy_isspace(*(p+1))) { char *q = p+1; while (privoxy_isspace(*q)) { q++; } log_error(LOG_LEVEL_HEADER, "Reducing white space in '%s'", header); string_move(p+1, q); } if (*p == '\t') { log_error(LOG_LEVEL_HEADER, "Converting tab to space in '%s'", header); *p = ' '; } else if (*p == '"') { char *end_of_token = strstr(p+1, "\""); if (NULL != end_of_token) { /* Don't mess with quoted text. */ p = end_of_token; } else { log_error(LOG_LEVEL_HEADER, "Ignoring single quote in '%s'", header); } } p++; } p = strchr(header, ':'); if ((p != NULL) && (p != header) && privoxy_isspace(*(p-1))) { /* * There's still space before the colon. * We don't want it. */ string_move(p-1, p); } } /********************************************************************* * * Function : get_header * * Description : This (odd) routine will parse the csp->iob * to get the next complete header. * * Parameters : * 1 : iob = The I/O buffer to parse, usually csp->iob. * * Returns : Any one of the following: * * 1) a pointer to a dynamically allocated string that contains a header line * 2) NULL indicating that the end of the header was reached * 3) "" indicating that the end of the iob was reached before finding * a complete header line. * *********************************************************************/ char *get_header(struct iob *iob) { char *header; header = get_header_line(iob); if ((header == NULL) || (*header == '\0')) { /* * No complete header read yet, tell the client. */ return header; } while ((iob->cur[0] == ' ') || (iob->cur[0] == '\t')) { /* * Header spans multiple lines, append the next one. */ char *continued_header; continued_header = get_header_line(iob); if ((continued_header == NULL) || (*continued_header == '\0')) { /* * No complete header read yet, return what we got. * XXX: Should "unread" header instead. */ log_error(LOG_LEVEL_INFO, "Failed to read a multi-line header properly: '%s'", header); break; } if (JB_ERR_OK != string_join(&header, continued_header)) { log_error(LOG_LEVEL_FATAL, "Out of memory while appending multiple headers."); } else { /* XXX: remove before next stable release. */ log_error(LOG_LEVEL_HEADER, "Merged multiple header lines to: '%s'", header); } } normalize_lws(header); return header; } /********************************************************************* * * Function : get_header_line * * Description : This (odd) routine will parse the csp->iob * to get the next header line. * * Parameters : * 1 : iob = The I/O buffer to parse, usually csp->iob. * * Returns : Any one of the following: * * 1) a pointer to a dynamically allocated string that contains a header line * 2) NULL indicating that the end of the header was reached * 3) "" indicating that the end of the iob was reached before finding * a complete header line. * *********************************************************************/ static char *get_header_line(struct iob *iob) { char *p, *q, *ret; if ((iob->cur == NULL) || ((p = strchr(iob->cur, '\n')) == NULL)) { return(""); /* couldn't find a complete header */ } *p = '\0'; ret = strdup(iob->cur); if (ret == NULL) { /* FIXME No way to handle error properly */ log_error(LOG_LEVEL_FATAL, "Out of memory in get_header_line()"); } assert(ret != NULL); iob->cur = p+1; if ((q = strchr(ret, '\r')) != NULL) *q = '\0'; /* is this a blank line (i.e. the end of the header) ? */ if (*ret == '\0') { freez(ret); return NULL; } return ret; } /********************************************************************* * * Function : get_header_value * * Description : Get the value of a given header from a chained list * of header lines or return NULL if no such header is * present in the list. * * Parameters : * 1 : header_list = pointer to list * 2 : header_name = string with name of header to look for. * Trailing colon required, capitalization * doesn't matter. * * Returns : NULL if not found, else value of header * *********************************************************************/ char *get_header_value(const struct list *header_list, const char *header_name) { struct list_entry *cur_entry; char *ret = NULL; size_t length = 0; assert(header_list); assert(header_name); length = strlen(header_name); for (cur_entry = header_list->first; cur_entry ; cur_entry = cur_entry->next) { if (cur_entry->str) { if (!strncmpic(cur_entry->str, header_name, length)) { /* * Found: return pointer to start of value */ ret = cur_entry->str + length; while (*ret && privoxy_isspace(*ret)) ret++; return ret; } } } /* * Not found */ return NULL; } /********************************************************************* * * Function : scan_headers * * Description : Scans headers, applies tags and updates action bits. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : JB_ERR_OK * *********************************************************************/ static jb_err scan_headers(struct client_state *csp) { struct list_entry *h; /* Header */ jb_err err = JB_ERR_OK; for (h = csp->headers->first; (err == JB_ERR_OK) && (h != NULL) ; h = h->next) { /* Header crunch()ed in previous run? -> ignore */ if (h->str == NULL) continue; log_error(LOG_LEVEL_HEADER, "scan: %s", h->str); err = header_tagger(csp, h->str); } return err; } /********************************************************************* * * Function : enforce_header_order * * Description : Enforces a given header order. * * Parameters : * 1 : headers = List of headers to order. * 2 : ordered_headers = List of ordered header names. * * Returns : N/A * *********************************************************************/ static void enforce_header_order(struct list *headers, const struct list *ordered_headers) { struct list_entry *sorted_header; struct list new_headers[1]; struct list_entry *header; init_list(new_headers); /* The request line is always the first "header" */ assert(NULL != headers->first->str); enlist(new_headers, headers->first->str); freez(headers->first->str) /* Enlist the specified headers in the given order */ for (sorted_header = ordered_headers->first; sorted_header != NULL; sorted_header = sorted_header->next) { const size_t sorted_header_length = strlen(sorted_header->str); for (header = headers->first; header != NULL; header = header->next) { /* Header enlisted in previous run? -> ignore */ if (header->str == NULL) continue; if (0 == strncmpic(sorted_header->str, header->str, sorted_header_length) && (header->str[sorted_header_length] == ':')) { log_error(LOG_LEVEL_HEADER, "Enlisting sorted header %s", header->str); if (JB_ERR_OK != enlist(new_headers, header->str)) { log_error(LOG_LEVEL_HEADER, "Failed to enlist %s", header->str); } freez(header->str); } } } /* Enlist the rest of the headers behind the ordered ones */ for (header = headers->first; header != NULL; header = header->next) { /* Header enlisted in previous run? -> ignore */ if (header->str == NULL) continue; log_error(LOG_LEVEL_HEADER, "Enlisting left-over header %s", header->str); if (JB_ERR_OK != enlist(new_headers, header->str)) { log_error(LOG_LEVEL_HEADER, "Failed to enlist %s", header->str); } freez(header->str); } list_remove_all(headers); list_duplicate(headers, new_headers); list_remove_all(new_headers); return; } /********************************************************************* * * Function : sed * * Description : add, delete or modify lines in the HTTP header streams. * On entry, it receives a linked list of headers space * that was allocated dynamically (both the list nodes * and the header contents). * * As a side effect it frees the space used by the original * header lines. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : filter_server_headers = Boolean to switch between * server and header filtering. * * Returns : JB_ERR_OK in case off success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ jb_err sed(struct client_state *csp, int filter_server_headers) { /* XXX: use more descriptive names. */ struct list_entry *p; const struct parsers *v; const add_header_func_ptr *f; jb_err err = JB_ERR_OK; scan_headers(csp); if (filter_server_headers) { v = server_patterns; f = add_server_headers; check_negative_tag_patterns(csp, PATTERN_SPEC_NO_RESPONSE_TAG_PATTERN); } else { v = client_patterns; f = add_client_headers; check_negative_tag_patterns(csp, PATTERN_SPEC_NO_REQUEST_TAG_PATTERN); } while ((err == JB_ERR_OK) && (v->str != NULL)) { for (p = csp->headers->first; (err == JB_ERR_OK) && (p != NULL); p = p->next) { /* Header crunch()ed in previous run? -> ignore */ if (p->str == NULL) continue; /* Does the current parser handle this header? */ if ((strncmpic(p->str, v->str, v->len) == 0) || (v->len == CHECK_EVERY_HEADER_REMAINING)) { err = v->parser(csp, &(p->str)); } } v++; } /* place additional headers on the csp->headers list */ while ((err == JB_ERR_OK) && (*f)) { err = (*f)(csp); f++; } if (!filter_server_headers && !list_is_empty(csp->config->ordered_client_headers)) { enforce_header_order(csp->headers, csp->config->ordered_client_headers); } return err; } /********************************************************************* * * Function : update_server_headers * * Description : Updates server headers after the body has been modified. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : JB_ERR_OK in case off success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ jb_err update_server_headers(struct client_state *csp) { jb_err err = JB_ERR_OK; static const struct parsers server_patterns_light[] = { { "Content-Length:", 15, server_adjust_content_length }, { "Transfer-Encoding:", 18, server_transfer_coding }, #ifdef FEATURE_ZLIB { "Content-Encoding:", 17, server_adjust_content_encoding }, #endif /* def FEATURE_ZLIB */ { NULL, 0, NULL } }; if (strncmpic(csp->http->cmd, "HEAD", 4)) { const struct parsers *v; struct list_entry *p; for (v = server_patterns_light; (err == JB_ERR_OK) && (v->str != NULL); v++) { for (p = csp->headers->first; (err == JB_ERR_OK) && (p != NULL); p = p->next) { /* Header crunch()ed in previous run? -> ignore */ if (p->str == NULL) continue; /* Does the current parser handle this header? */ if (strncmpic(p->str, v->str, v->len) == 0) { err = v->parser(csp, (char **)&(p->str)); } } } } #ifdef FEATURE_CONNECTION_KEEP_ALIVE if ((JB_ERR_OK == err) && (csp->flags & CSP_FLAG_MODIFIED) && (csp->flags & CSP_FLAG_CLIENT_CONNECTION_KEEP_ALIVE) && !(csp->flags & CSP_FLAG_SERVER_CONTENT_LENGTH_SET)) { char header[50]; create_content_length_header(csp->content_length, header, sizeof(header)); err = enlist(csp->headers, header); if (JB_ERR_OK == err) { log_error(LOG_LEVEL_HEADER, "Content modified with no Content-Length header set. " "Created: %s.", header); csp->flags |= CSP_FLAG_SERVER_CONTENT_LENGTH_SET; } } #endif /* def FEATURE_CONNECTION_KEEP_ALIVE */ #ifdef FEATURE_COMPRESSION if ((JB_ERR_OK == err) && (csp->flags & CSP_FLAG_BUFFERED_CONTENT_DEFLATED)) { err = enlist_unique_header(csp->headers, "Content-Encoding", "deflate"); if (JB_ERR_OK == err) { log_error(LOG_LEVEL_HEADER, "Added header: Content-Encoding: deflate"); } } #endif return err; } /********************************************************************* * * Function : header_tagger * * Description : Executes all text substitutions from applying * tag actions and saves the result as tag. * * XXX: Shares enough code with filter_header() and * pcrs_filter_response() to warrant some helper functions. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = Header that is used as tagger input * * Returns : JB_ERR_OK on success and always succeeds * *********************************************************************/ static jb_err header_tagger(struct client_state *csp, char *header) { enum filter_type wanted_filter_type; int multi_action_index; pcrs_job *job; struct re_filterfile_spec *b; struct list_entry *tag_name; const size_t header_length = strlen(header); if (csp->flags & CSP_FLAG_CLIENT_HEADER_PARSING_DONE) { wanted_filter_type = FT_SERVER_HEADER_TAGGER; multi_action_index = ACTION_MULTI_SERVER_HEADER_TAGGER; } else { wanted_filter_type = FT_CLIENT_HEADER_TAGGER; multi_action_index = ACTION_MULTI_CLIENT_HEADER_TAGGER; } if (list_is_empty(csp->action->multi[multi_action_index]) || filters_available(csp) == FALSE) { /* Return early if no taggers apply or if none are available. */ return JB_ERR_OK; } /* Execute all applying taggers */ for (tag_name = csp->action->multi[multi_action_index]->first; NULL != tag_name; tag_name = tag_name->next) { char *modified_tag = NULL; char *tag = header; size_t size = header_length; pcrs_job *joblist; b = get_filter(csp, tag_name->str, wanted_filter_type); if (b == NULL) { continue; } joblist = b->joblist; if (b->dynamic) joblist = compile_dynamic_pcrs_job_list(csp, b); if (NULL == joblist) { log_error(LOG_LEVEL_RE_FILTER, "Tagger %s has empty joblist. Nothing to do.", b->name); continue; } /* execute their pcrs_joblist on the header. */ for (job = joblist; NULL != job; job = job->next) { const int hits = pcrs_execute(job, tag, size, &modified_tag, &size); if (0 < hits) { /* Success, continue with the modified version. */ if (tag != header) { freez(tag); } tag = modified_tag; } else { /* Tagger doesn't match */ if (0 > hits) { /* Regex failure, log it but continue anyway. */ assert(NULL != header); log_error(LOG_LEVEL_ERROR, "Problems with tagger \'%s\' and header \'%s\': %s", b->name, *header, pcrs_strerror(hits)); } freez(modified_tag); } } if (b->dynamic) pcrs_free_joblist(joblist); /* If this tagger matched */ if (tag != header) { if (0 == size) { /* * There is no technical limitation which makes * it impossible to use empty tags, but I assume * no one would do it intentionally. */ freez(tag); log_error(LOG_LEVEL_INFO, "Tagger \'%s\' created an empty tag. Ignored.", b->name); continue; } if (!list_contains_item(csp->tags, tag)) { if (JB_ERR_OK != enlist(csp->tags, tag)) { log_error(LOG_LEVEL_ERROR, "Insufficient memory to add tag \'%s\', " "based on tagger \'%s\' and header \'%s\'", tag, b->name, *header); } else { char *action_message; /* * update the action bits right away, to make * tagging based on tags set by earlier taggers * of the same kind possible. */ if (update_action_bits_for_tag(csp, tag)) { action_message = "Action bits updated accordingly."; } else { action_message = "No action bits update necessary."; } log_error(LOG_LEVEL_HEADER, "Tagger \'%s\' added tag \'%s\'. %s", b->name, tag, action_message); } } else { /* XXX: Is this log-worthy? */ log_error(LOG_LEVEL_HEADER, "Tagger \'%s\' didn't add tag \'%s\'. Tag already present", b->name, tag); } freez(tag); } } return JB_ERR_OK; } /* here begins the family of parser functions that reformat header lines */ /********************************************************************* * * Function : filter_header * * Description : Executes all text substitutions from all applying * +(server|client)-header-filter actions on the header. * Most of the code was copied from pcrs_filter_response, * including the rather short variable names * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success and always succeeds * *********************************************************************/ static jb_err filter_header(struct client_state *csp, char **header) { int hits=0; int matches; size_t size = strlen(*header); char *newheader = NULL; pcrs_job *job; struct re_filterfile_spec *b; struct list_entry *filtername; enum filter_type wanted_filter_type; int multi_action_index; if (csp->flags & CSP_FLAG_NO_FILTERING) { return JB_ERR_OK; } if (csp->flags & CSP_FLAG_CLIENT_HEADER_PARSING_DONE) { wanted_filter_type = FT_SERVER_HEADER_FILTER; multi_action_index = ACTION_MULTI_SERVER_HEADER_FILTER; } else { wanted_filter_type = FT_CLIENT_HEADER_FILTER; multi_action_index = ACTION_MULTI_CLIENT_HEADER_FILTER; } if (list_is_empty(csp->action->multi[multi_action_index]) || filters_available(csp) == FALSE) { /* Return early if no filters apply or if none are available. */ return JB_ERR_OK; } /* Execute all applying header filters */ for (filtername = csp->action->multi[multi_action_index]->first; filtername != NULL; filtername = filtername->next) { int current_hits = 0; pcrs_job *joblist; b = get_filter(csp, filtername->str, wanted_filter_type); if (b == NULL) { continue; } joblist = b->joblist; if (b->dynamic) joblist = compile_dynamic_pcrs_job_list(csp, b); if (NULL == joblist) { log_error(LOG_LEVEL_RE_FILTER, "Filter %s has empty joblist. Nothing to do.", b->name); continue; } log_error(LOG_LEVEL_RE_FILTER, "filtering \'%s\' (size %d) with \'%s\' ...", *header, size, b->name); /* Apply all jobs from the joblist */ for (job = joblist; NULL != job; job = job->next) { matches = pcrs_execute(job, *header, size, &newheader, &size); if (0 < matches) { current_hits += matches; log_error(LOG_LEVEL_HEADER, "Transforming \"%s\" to \"%s\"", *header, newheader); freez(*header); *header = newheader; } else if (0 == matches) { /* Filter doesn't change header */ freez(newheader); } else { /* RegEx failure */ log_error(LOG_LEVEL_ERROR, "Filtering \'%s\' with \'%s\' didn't work out: %s", *header, b->name, pcrs_strerror(matches)); if (newheader != NULL) { log_error(LOG_LEVEL_ERROR, "Freeing what's left: %s", newheader); freez(newheader); } } } if (b->dynamic) pcrs_free_joblist(joblist); log_error(LOG_LEVEL_RE_FILTER, "... produced %d hits (new size %d).", current_hits, size); hits += current_hits; } /* * Additionally checking for hits is important because if * the continue hack is triggered, server headers can * arrive empty to separate multiple heads from each other. */ if ((0 == size) && hits) { log_error(LOG_LEVEL_HEADER, "Removing empty header %s", *header); freez(*header); } return JB_ERR_OK; } /********************************************************************* * * Function : server_connection * * Description : Makes sure a proper "Connection:" header is * set and signals connection_header_adder to * do nothing. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success. * *********************************************************************/ static jb_err server_connection(struct client_state *csp, char **header) { if (!strcmpic(*header, "Connection: keep-alive") #ifdef FEATURE_CONNECTION_KEEP_ALIVE && !(csp->flags & CSP_FLAG_SERVER_SOCKET_TAINTED) #endif ) { #ifdef FEATURE_CONNECTION_KEEP_ALIVE if ((csp->config->feature_flags & RUNTIME_FEATURE_CONNECTION_KEEP_ALIVE)) { csp->flags |= CSP_FLAG_SERVER_CONNECTION_KEEP_ALIVE; } if ((csp->flags & CSP_FLAG_CLIENT_CONNECTION_KEEP_ALIVE)) { log_error(LOG_LEVEL_HEADER, "Keeping the server header '%s' around.", *header); } else #endif /* FEATURE_CONNECTION_KEEP_ALIVE */ { char *old_header = *header; *header = strdup_or_die("Connection: close"); log_error(LOG_LEVEL_HEADER, "Replaced: \'%s\' with \'%s\'", old_header, *header); freez(old_header); } } /* Signal server_connection_adder() to return early. */ csp->flags |= CSP_FLAG_SERVER_CONNECTION_HEADER_SET; return JB_ERR_OK; } #ifdef FEATURE_CONNECTION_KEEP_ALIVE /********************************************************************* * * Function : server_keep_alive * * Description : Stores the server's keep alive timeout. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK. * *********************************************************************/ static jb_err server_keep_alive(struct client_state *csp, char **header) { unsigned int keep_alive_timeout; const char *timeout_position = strstr(*header, "timeout="); if ((NULL == timeout_position) || (1 != sscanf(timeout_position, "timeout=%u", &keep_alive_timeout))) { log_error(LOG_LEVEL_ERROR, "Couldn't parse: %s", *header); } else { if (keep_alive_timeout < csp->server_connection.keep_alive_timeout) { log_error(LOG_LEVEL_HEADER, "Reducing keep-alive timeout from %u to %u.", csp->server_connection.keep_alive_timeout, keep_alive_timeout); csp->server_connection.keep_alive_timeout = keep_alive_timeout; } else { /* XXX: Is this log worthy? */ log_error(LOG_LEVEL_HEADER, "Server keep-alive timeout is %u. Sticking with %u.", keep_alive_timeout, csp->server_connection.keep_alive_timeout); } csp->flags |= CSP_FLAG_SERVER_KEEP_ALIVE_TIMEOUT_SET; } return JB_ERR_OK; } /********************************************************************* * * Function : server_proxy_connection * * Description : Figures out whether or not we should add a * Proxy-Connection header. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK. * *********************************************************************/ static jb_err server_proxy_connection(struct client_state *csp, char **header) { csp->flags |= CSP_FLAG_SERVER_PROXY_CONNECTION_HEADER_SET; return JB_ERR_OK; } /********************************************************************* * * Function : proxy_authentication * * Description : Removes headers that are relevant for proxy * authentication unless forwarding them has * been explicitly requested. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK. * *********************************************************************/ static jb_err proxy_authentication(struct client_state *csp, char **header) { if ((csp->config->feature_flags & RUNTIME_FEATURE_FORWARD_PROXY_AUTHENTICATION_HEADERS) == 0) { log_error(LOG_LEVEL_HEADER, "Forwarding proxy authentication headers is disabled. Crunching: %s", *header); freez(*header); } return JB_ERR_OK; } /********************************************************************* * * Function : client_keep_alive * * Description : Stores the client's keep alive timeout. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK. * *********************************************************************/ static jb_err client_keep_alive(struct client_state *csp, char **header) { unsigned int keep_alive_timeout; char *timeout_position; if (!(csp->config->feature_flags & RUNTIME_FEATURE_CONNECTION_KEEP_ALIVE)) { log_error(LOG_LEVEL_HEADER, "keep-alive support is disabled. Crunching: %s.", *header); freez(*header); return JB_ERR_OK; } /* Check for parameter-less format "Keep-Alive: 100" */ timeout_position = strstr(*header, ": "); if ((NULL == timeout_position) || (1 != sscanf(timeout_position, ": %u", &keep_alive_timeout))) { /* Assume parameter format "Keep-Alive: timeout=100" */ timeout_position = strstr(*header, "timeout="); if ((NULL == timeout_position) || (1 != sscanf(timeout_position, "timeout=%u", &keep_alive_timeout))) { log_error(LOG_LEVEL_HEADER, "Couldn't parse: '%s'. Using default timeout %u", *header, csp->config->keep_alive_timeout); freez(*header); return JB_ERR_OK; } } if (keep_alive_timeout < csp->config->keep_alive_timeout) { log_error(LOG_LEVEL_HEADER, "Reducing keep-alive timeout from %u to %u.", csp->config->keep_alive_timeout, keep_alive_timeout); csp->server_connection.keep_alive_timeout = keep_alive_timeout; } else { /* XXX: Is this log worthy? */ log_error(LOG_LEVEL_HEADER, "Client keep-alive timeout is %u. Sticking with %u.", keep_alive_timeout, csp->config->keep_alive_timeout); freez(*header); } return JB_ERR_OK; } /********************************************************************* * * Function : get_content_length * * Description : Gets the content length specified in a * Content-Length header. * * Parameters : * 1 : header_value = The Content-Length header value. * 2 : length = Storage to return the value. * * Returns : JB_ERR_OK on success, or * JB_ERR_PARSE if no value is recognized. * *********************************************************************/ static jb_err get_content_length(const char *header_value, unsigned long long *length) { #ifdef _WIN32 assert(sizeof(unsigned long long) > 4); if (1 != sscanf(header_value, "%I64u", length)) #else if (1 != sscanf(header_value, "%llu", length)) #endif { return JB_ERR_PARSE; } return JB_ERR_OK; } /********************************************************************* * * Function : client_save_content_length * * Description : Save the Content-Length sent by the client. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_save_content_length(struct client_state *csp, char **header) { unsigned long long content_length = 0; const char *header_value; assert(*(*header+14) == ':'); header_value = *header + 15; if (JB_ERR_OK != get_content_length(header_value, &content_length)) { log_error(LOG_LEVEL_ERROR, "Crunching invalid header: %s", *header); freez(*header); } else { csp->expected_client_content_length = content_length; } return JB_ERR_OK; } #endif /* def FEATURE_CONNECTION_KEEP_ALIVE */ /********************************************************************* * * Function : client_connection * * Description : Makes sure a proper "Connection:" header is * set and signals connection_header_adder * to do nothing. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success. * *********************************************************************/ static jb_err client_connection(struct client_state *csp, char **header) { static const char connection_close[] = "Connection: close"; if (!strcmpic(*header, connection_close)) { #ifdef FEATURE_CONNECTION_KEEP_ALIVE if ((csp->config->feature_flags & RUNTIME_FEATURE_CONNECTION_SHARING) && !(csp->flags & CSP_FLAG_SERVER_SOCKET_TAINTED)) { if (!strcmpic(csp->http->ver, "HTTP/1.1")) { log_error(LOG_LEVEL_HEADER, "Removing \'%s\' to imply keep-alive.", *header); freez(*header); /* * While we imply keep-alive to the server, * we have to remember that the client didn't. */ csp->flags &= ~CSP_FLAG_CLIENT_CONNECTION_KEEP_ALIVE; } else { char *old_header = *header; *header = strdup_or_die("Connection: keep-alive"); log_error(LOG_LEVEL_HEADER, "Replaced: \'%s\' with \'%s\'", old_header, *header); freez(old_header); } } else { log_error(LOG_LEVEL_HEADER, "Keeping the client header '%s' around. " "The connection will not be kept alive.", *header); csp->flags &= ~CSP_FLAG_CLIENT_CONNECTION_KEEP_ALIVE; } } else if ((csp->config->feature_flags & RUNTIME_FEATURE_CONNECTION_KEEP_ALIVE) && !(csp->flags & CSP_FLAG_SERVER_SOCKET_TAINTED)) { log_error(LOG_LEVEL_HEADER, "Keeping the client header '%s' around. " "The server connection will be kept alive if possible.", *header); csp->flags |= CSP_FLAG_CLIENT_CONNECTION_KEEP_ALIVE; #endif /* def FEATURE_CONNECTION_KEEP_ALIVE */ } else { char *old_header = *header; *header = strdup_or_die(connection_close); log_error(LOG_LEVEL_HEADER, "Replaced: \'%s\' with \'%s\'", old_header, *header); freez(old_header); } /* Signal client_connection_header_adder() to return early. */ csp->flags |= CSP_FLAG_CLIENT_CONNECTION_HEADER_SET; return JB_ERR_OK; } #ifdef FEATURE_CONNECTION_KEEP_ALIVE /********************************************************************* * * Function : client_proxy_connection * * Description : Sets the CLIENT_CONNECTION_KEEP_ALIVE flag when * appropriate and removes the Proxy-Connection * header. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK * *********************************************************************/ static jb_err client_proxy_connection(struct client_state *csp, char **header) { if (0 == (csp->flags & CSP_FLAG_CLIENT_CONNECTION_KEEP_ALIVE) && (csp->http->ssl == 0) && (NULL == strstr(*header, "close"))) { log_error(LOG_LEVEL_HEADER, "The client connection can be kept alive due to: %s", *header); csp->flags |= CSP_FLAG_CLIENT_CONNECTION_KEEP_ALIVE; } crumble(csp, header); return JB_ERR_OK; } #endif /* def FEATURE_CONNECTION_KEEP_ALIVE */ /********************************************************************* * * Function : client_transfer_encoding * * Description : Raise the CSP_FLAG_CHUNKED_CLIENT_BODY flag if * the request body is "chunked" * * XXX: Currently not called through sed() as we * need the flag earlier on. Should be fixed. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * *********************************************************************/ jb_err client_transfer_encoding(struct client_state *csp, char **header) { if (strstr(*header, "chunked")) { csp->flags |= CSP_FLAG_CHUNKED_CLIENT_BODY; log_error(LOG_LEVEL_HEADER, "Expecting chunked client body"); } return JB_ERR_OK; } /********************************************************************* * * Function : crumble * * Description : This is called if a header matches a pattern to "crunch" * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err crumble(struct client_state *csp, char **header) { (void)csp; log_error(LOG_LEVEL_HEADER, "crumble crunched: %s!", *header); freez(*header); return JB_ERR_OK; } /********************************************************************* * * Function : crunch_server_header * * Description : Crunch server header if it matches a string supplied by the * user. Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success and always succeeds * *********************************************************************/ static jb_err crunch_server_header(struct client_state *csp, char **header) { const char *crunch_pattern; /* Do we feel like crunching? */ if ((csp->action->flags & ACTION_CRUNCH_SERVER_HEADER)) { crunch_pattern = csp->action->string[ACTION_STRING_SERVER_HEADER]; /* Is the current header the lucky one? */ if (strstr(*header, crunch_pattern)) { log_error(LOG_LEVEL_HEADER, "Crunching server header: %s (contains: %s)", *header, crunch_pattern); freez(*header); } } return JB_ERR_OK; } /********************************************************************* * * Function : server_content_type * * Description : Set the content-type for filterable types (text/.*, * .*xml.*, .*script.* and image/gif) unless filtering has been * forbidden (CT_TABOO) while parsing earlier headers. * NOTE: Since text/plain is commonly used by web servers * for files whose correct type is unknown, we don't * set CT_TEXT for it. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err server_content_type(struct client_state *csp, char **header) { /* Remove header if it isn't the first Content-Type header */ if ((csp->content_type & CT_DECLARED)) { if (content_filters_enabled(csp->action)) { /* * Making sure the client interprets the content the same way * Privoxy did is only relevant if Privoxy modified it. * * Checking for this is "hard" as it's not yet known when * this function is called, thus go shopping and and just * check if Privoxy could filter it. * * The main thing is that we don't mess with the headers * unless the user signalled that it's acceptable. */ log_error(LOG_LEVEL_HEADER, "Multiple Content-Type headers detected. " "Removing and ignoring: %s", *header); freez(*header); } return JB_ERR_OK; } /* * Signal that the Content-Type has been set. */ csp->content_type |= CT_DECLARED; if (!(csp->content_type & CT_TABOO)) { /* * XXX: The assumption that text/plain is a sign of * binary data seems to be somewhat unreasonable nowadays * and should be dropped after 3.0.8 is out. */ if ((strstr(*header, "text/") && !strstr(*header, "plain")) || strstr(*header, "xml") || strstr(*header, "script")) { csp->content_type |= CT_TEXT; } else if (strstr(*header, "image/gif")) { csp->content_type |= CT_GIF; } } /* * Are we messing with the content type? */ if (csp->action->flags & ACTION_CONTENT_TYPE_OVERWRITE) { /* * Make sure the user doesn't accidentally * change the content type of binary documents. */ if ((csp->content_type & CT_TEXT) || (csp->action->flags & ACTION_FORCE_TEXT_MODE)) { freez(*header); *header = strdup_or_die("Content-Type: "); string_append(header, csp->action->string[ACTION_STRING_CONTENT_TYPE]); if (header == NULL) { log_error(LOG_LEVEL_HEADER, "Insufficient memory to replace Content-Type!"); return JB_ERR_MEMORY; } log_error(LOG_LEVEL_HEADER, "Modified: %s!", *header); } else { log_error(LOG_LEVEL_HEADER, "%s not replaced. " "It doesn't look like a content type that should be filtered. " "Enable force-text-mode if you know what you're doing.", *header); } } return JB_ERR_OK; } /********************************************************************* * * Function : server_transfer_coding * * Description : - Prohibit filtering (CT_TABOO) if transfer coding compresses * - Raise the CSP_FLAG_CHUNKED flag if coding is "chunked" * - Remove header if body was chunked but has been * de-chunked for filtering. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err server_transfer_coding(struct client_state *csp, char **header) { /* * Turn off pcrs and gif filtering if body compressed */ if (strstr(*header, "gzip") || strstr(*header, "compress") || strstr(*header, "deflate")) { #ifdef FEATURE_ZLIB /* * XXX: Added to test if we could use CT_GZIP and CT_DEFLATE here. */ log_error(LOG_LEVEL_INFO, "Marking content type for %s as CT_TABOO because of %s.", csp->http->cmd, *header); #endif /* def FEATURE_ZLIB */ csp->content_type = CT_TABOO; } /* * Raise flag if body chunked */ if (strstr(*header, "chunked")) { csp->flags |= CSP_FLAG_CHUNKED; /* * If the body was modified, it has been de-chunked first * and the header must be removed. * * FIXME: If there is more than one transfer encoding, * only the "chunked" part should be removed here. */ if (csp->flags & CSP_FLAG_MODIFIED) { log_error(LOG_LEVEL_HEADER, "Removing: %s", *header); freez(*header); } } return JB_ERR_OK; } /********************************************************************* * * Function : server_content_encoding * * Description : Used to check if the content is compressed, and if * FEATURE_ZLIB is disabled, filtering is disabled as * well. * * If FEATURE_ZLIB is enabled and the compression type * supported, the content is marked for decompression. * * XXX: Doesn't properly deal with multiple or with * unsupported but unknown encodings. * Is case-sensitive but shouldn't be. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err server_content_encoding(struct client_state *csp, char **header) { #ifdef FEATURE_ZLIB if (strstr(*header, "sdch")) { /* * Shared Dictionary Compression over HTTP isn't supported, * filtering it anyway is pretty much guaranteed to mess up * the encoding. */ csp->content_type |= CT_TABOO; /* * Log a warning if the user expects the content to be filtered. */ if ((csp->rlist != NULL) && (!list_is_empty(csp->action->multi[ACTION_MULTI_FILTER]))) { log_error(LOG_LEVEL_INFO, "SDCH-compressed content detected, content filtering disabled. " "Consider suppressing SDCH offers made by the client."); } } else if (strstr(*header, "gzip")) { /* Mark for gzip decompression */ csp->content_type |= CT_GZIP; } else if (strstr(*header, "deflate")) { /* Mark for zlib decompression */ csp->content_type |= CT_DEFLATE; } else if (strstr(*header, "compress")) { /* * We can't decompress this; therefore we can't filter * it either. */ csp->content_type |= CT_TABOO; } #else /* !defined(FEATURE_ZLIB) */ /* * XXX: Using a black list here isn't the right approach. * * In case of SDCH, building with zlib support isn't * going to help. */ if (strstr(*header, "gzip") || strstr(*header, "compress") || strstr(*header, "deflate") || strstr(*header, "sdch")) { /* * Body is compressed, turn off pcrs and gif filtering. */ csp->content_type |= CT_TABOO; /* * Log a warning if the user expects the content to be filtered. */ if ((csp->rlist != NULL) && (!list_is_empty(csp->action->multi[ACTION_MULTI_FILTER]))) { log_error(LOG_LEVEL_INFO, "Compressed content detected, content filtering disabled. " "Consider recompiling Privoxy with zlib support or " "enable the prevent-compression action."); } } #endif /* defined(FEATURE_ZLIB) */ return JB_ERR_OK; } #ifdef FEATURE_ZLIB /********************************************************************* * * Function : server_adjust_content_encoding * * Description : Remove the Content-Encoding header if the * decompression was successful and the content * has been modifed. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err server_adjust_content_encoding(struct client_state *csp, char **header) { if ((csp->flags & CSP_FLAG_MODIFIED) && (csp->content_type & (CT_GZIP | CT_DEFLATE))) { /* * We successfully decompressed the content, * and have to clean the header now, so the * client no longer expects compressed data. * * XXX: There is a difference between cleaning * and removing it completely. */ log_error(LOG_LEVEL_HEADER, "Crunching: %s", *header); freez(*header); } return JB_ERR_OK; } #endif /* defined(FEATURE_ZLIB) */ /********************************************************************* * * Function : server_adjust_content_length * * Description : Adjust Content-Length header if we modified * the body. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err server_adjust_content_length(struct client_state *csp, char **header) { /* Regenerate header if the content was modified. */ if (csp->flags & CSP_FLAG_MODIFIED) { const size_t header_length = 50; freez(*header); *header = malloc(header_length); if (*header == NULL) { return JB_ERR_MEMORY; } create_content_length_header(csp->content_length, *header, header_length); log_error(LOG_LEVEL_HEADER, "Adjusted Content-Length to %llu", csp->content_length); } return JB_ERR_OK; } #ifdef FEATURE_CONNECTION_KEEP_ALIVE /********************************************************************* * * Function : server_save_content_length * * Description : Save the Content-Length sent by the server. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err server_save_content_length(struct client_state *csp, char **header) { unsigned long long content_length = 0; const char *header_value; assert(*(*header+14) == ':'); header_value = *header + 15; if (JB_ERR_OK != get_content_length(header_value, &content_length)) { log_error(LOG_LEVEL_ERROR, "Crunching invalid header: %s", *header); freez(*header); } else { csp->expected_content_length = content_length; csp->flags |= CSP_FLAG_SERVER_CONTENT_LENGTH_SET; csp->flags |= CSP_FLAG_CONTENT_LENGTH_SET; } return JB_ERR_OK; } #endif /* def FEATURE_CONNECTION_KEEP_ALIVE */ /********************************************************************* * * Function : server_content_md5 * * Description : Crumble any Content-MD5 headers if the document was * modified. FIXME: Should we re-compute instead? * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err server_content_md5(struct client_state *csp, char **header) { if (csp->flags & CSP_FLAG_MODIFIED) { log_error(LOG_LEVEL_HEADER, "Crunching Content-MD5"); freez(*header); } return JB_ERR_OK; } /********************************************************************* * * Function : server_content_disposition * * Description : If enabled, blocks or modifies the "Content-Disposition" header. * Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err server_content_disposition(struct client_state *csp, char **header) { const char *newval; /* * Are we messing with the Content-Disposition header? */ if ((csp->action->flags & ACTION_HIDE_CONTENT_DISPOSITION) == 0) { /* Me tinks not */ return JB_ERR_OK; } newval = csp->action->string[ACTION_STRING_CONTENT_DISPOSITION]; if ((newval == NULL) || (0 == strcmpic(newval, "block"))) { /* * Blocking content-disposition header */ log_error(LOG_LEVEL_HEADER, "Crunching %s!", *header); freez(*header); return JB_ERR_OK; } else { /* * Replacing Content-Disposition header */ freez(*header); *header = strdup("Content-Disposition: "); string_append(header, newval); if (*header != NULL) { log_error(LOG_LEVEL_HEADER, "Content-Disposition header crunched and replaced with: %s", *header); } } return (*header == NULL) ? JB_ERR_MEMORY : JB_ERR_OK; } /********************************************************************* * * Function : server_last_modified * * Description : Changes Last-Modified header to the actual date * to help hide-if-modified-since. * Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err server_last_modified(struct client_state *csp, char **header) { const char *newval; time_t last_modified; char newheader[50]; /* * Are we messing with the Last-Modified header? */ if ((csp->action->flags & ACTION_OVERWRITE_LAST_MODIFIED) == 0) { /*Nope*/ return JB_ERR_OK; } newval = csp->action->string[ACTION_STRING_LAST_MODIFIED]; if (0 == strcmpic(newval, "block")) { /* * Blocking Last-Modified header. Useless but why not. */ log_error(LOG_LEVEL_HEADER, "Crunching %s!", *header); freez(*header); return JB_ERR_OK; } else if (0 == strcmpic(newval, "reset-to-request-time")) { /* * Setting Last-Modified Header to now. */ char buf[30]; get_http_time(0, buf, sizeof(buf)); freez(*header); *header = strdup("Last-Modified: "); string_append(header, buf); if (*header == NULL) { log_error(LOG_LEVEL_HEADER, "Insufficient memory. Last-Modified header got lost, boohoo."); } else { log_error(LOG_LEVEL_HEADER, "Reset to present time: %s", *header); } } else if (0 == strcmpic(newval, "randomize")) { const char *header_time = *header + sizeof("Last-Modified:"); log_error(LOG_LEVEL_HEADER, "Randomizing: %s", *header); if (JB_ERR_OK != parse_header_time(header_time, &last_modified)) { log_error(LOG_LEVEL_HEADER, "Couldn't parse: %s in %s (crunching!)", header_time, *header); freez(*header); } else { time_t now; struct tm *timeptr = NULL; long int rtime; #ifdef HAVE_GMTIME_R struct tm gmt; #endif now = time(NULL); rtime = (long int)difftime(now, last_modified); if (rtime) { long int days, hours, minutes, seconds; const int negative_delta = (rtime < 0); if (negative_delta) { rtime *= -1; log_error(LOG_LEVEL_HEADER, "Server time in the future."); } rtime = pick_from_range(rtime); if (negative_delta) { rtime *= -1; } last_modified += rtime; #ifdef HAVE_GMTIME_R timeptr = gmtime_r(&last_modified, &gmt); #elif defined(MUTEX_LOCKS_AVAILABLE) privoxy_mutex_lock(&gmtime_mutex); timeptr = gmtime(&last_modified); privoxy_mutex_unlock(&gmtime_mutex); #else timeptr = gmtime(&last_modified); #endif if ((NULL == timeptr) || !strftime(newheader, sizeof(newheader), "%a, %d %b %Y %H:%M:%S GMT", timeptr)) { log_error(LOG_LEVEL_ERROR, "Randomizing '%s' failed. Crunching the header without replacement.", *header); freez(*header); return JB_ERR_OK; } freez(*header); *header = strdup("Last-Modified: "); string_append(header, newheader); if (*header == NULL) { log_error(LOG_LEVEL_ERROR, "Insufficient memory, header crunched without replacement."); return JB_ERR_MEMORY; } days = rtime / (3600 * 24); hours = rtime / 3600 % 24; minutes = rtime / 60 % 60; seconds = rtime % 60; log_error(LOG_LEVEL_HEADER, "Randomized: %s (added %d da%s %d hou%s %d minut%s %d second%s", *header, days, (days == 1) ? "y" : "ys", hours, (hours == 1) ? "r" : "rs", minutes, (minutes == 1) ? "e" : "es", seconds, (seconds == 1) ? ")" : "s)"); } else { log_error(LOG_LEVEL_HEADER, "Randomized ... or not. No time difference to work with."); } } } return JB_ERR_OK; } /********************************************************************* * * Function : client_accept_encoding * * Description : Rewrite the client's Accept-Encoding header so that * if doesn't allow compression, if the action applies. * Note: For HTTP/1.0 the absence of the header is enough. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_accept_encoding(struct client_state *csp, char **header) { #ifdef FEATURE_COMPRESSION if ((csp->config->feature_flags & RUNTIME_FEATURE_COMPRESSION) && strstr(*header, "deflate")) { csp->flags |= CSP_FLAG_CLIENT_SUPPORTS_DEFLATE; } #endif if ((csp->action->flags & ACTION_NO_COMPRESSION) != 0) { log_error(LOG_LEVEL_HEADER, "Suppressed offer to compress content"); freez(*header); } return JB_ERR_OK; } /********************************************************************* * * Function : client_te * * Description : Rewrite the client's TE header so that * if doesn't allow compression, if the action applies. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_te(struct client_state *csp, char **header) { if ((csp->action->flags & ACTION_NO_COMPRESSION) != 0) { freez(*header); log_error(LOG_LEVEL_HEADER, "Suppressed offer to compress transfer"); } return JB_ERR_OK; } /********************************************************************* * * Function : client_referrer * * Description : Handle the "referer" config setting properly. * Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_referrer(struct client_state *csp, char **header) { const char *parameter; /* booleans for parameters we have to check multiple times */ int parameter_conditional_block; int parameter_conditional_forge; #ifdef FEATURE_FORCE_LOAD /* * Since the referrer can include the prefix even * if the request itself is non-forced, we must * clean it unconditionally. * * XXX: strclean is too broad */ strclean(*header, FORCE_PREFIX); #endif /* def FEATURE_FORCE_LOAD */ if ((csp->action->flags & ACTION_HIDE_REFERER) == 0) { /* Nothing left to do */ return JB_ERR_OK; } parameter = csp->action->string[ACTION_STRING_REFERER]; assert(parameter != NULL); parameter_conditional_block = (0 == strcmpic(parameter, "conditional-block")); parameter_conditional_forge = (0 == strcmpic(parameter, "conditional-forge")); if (!parameter_conditional_block && !parameter_conditional_forge) { /* * As conditional-block and conditional-forge are the only * parameters that rely on the original referrer, we can * remove it now for all the others. */ freez(*header); } if (0 == strcmpic(parameter, "block")) { log_error(LOG_LEVEL_HEADER, "Referer crunched!"); return JB_ERR_OK; } else if (parameter_conditional_block || parameter_conditional_forge) { return handle_conditional_hide_referrer_parameter(header, csp->http->hostport, parameter_conditional_block); } else if (0 == strcmpic(parameter, "forge")) { return create_forged_referrer(header, csp->http->hostport); } else { /* interpret parameter as user-supplied referer to fake */ return create_fake_referrer(header, parameter); } } /********************************************************************* * * Function : client_accept_language * * Description : Handle the "Accept-Language" config setting properly. * Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_accept_language(struct client_state *csp, char **header) { const char *newval; /* * Are we messing with the Accept-Language? */ if ((csp->action->flags & ACTION_HIDE_ACCEPT_LANGUAGE) == 0) { /*I don't think so*/ return JB_ERR_OK; } newval = csp->action->string[ACTION_STRING_LANGUAGE]; if ((newval == NULL) || (0 == strcmpic(newval, "block"))) { /* * Blocking Accept-Language header */ log_error(LOG_LEVEL_HEADER, "Crunching Accept-Language!"); freez(*header); return JB_ERR_OK; } else { /* * Replacing Accept-Language header */ freez(*header); *header = strdup("Accept-Language: "); string_append(header, newval); if (*header == NULL) { log_error(LOG_LEVEL_ERROR, "Insufficient memory. Accept-Language header crunched without replacement."); } else { log_error(LOG_LEVEL_HEADER, "Accept-Language header crunched and replaced with: %s", *header); } } return (*header == NULL) ? JB_ERR_MEMORY : JB_ERR_OK; } /********************************************************************* * * Function : crunch_client_header * * Description : Crunch client header if it matches a string supplied by the * user. Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success and always succeeds * *********************************************************************/ static jb_err crunch_client_header(struct client_state *csp, char **header) { const char *crunch_pattern; /* Do we feel like crunching? */ if ((csp->action->flags & ACTION_CRUNCH_CLIENT_HEADER)) { crunch_pattern = csp->action->string[ACTION_STRING_CLIENT_HEADER]; /* Is the current header the lucky one? */ if (strstr(*header, crunch_pattern)) { log_error(LOG_LEVEL_HEADER, "Crunching client header: %s (contains: %s)", *header, crunch_pattern); freez(*header); } } return JB_ERR_OK; } /********************************************************************* * * Function : client_uagent * * Description : Handle the "user-agent" config setting properly * and remember its original value to enable browser * bug workarounds. Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_uagent(struct client_state *csp, char **header) { const char *newval; if ((csp->action->flags & ACTION_HIDE_USER_AGENT) == 0) { return JB_ERR_OK; } newval = csp->action->string[ACTION_STRING_USER_AGENT]; if (newval == NULL) { return JB_ERR_OK; } freez(*header); *header = strdup("User-Agent: "); string_append(header, newval); log_error(LOG_LEVEL_HEADER, "Modified: %s", *header); return (*header == NULL) ? JB_ERR_MEMORY : JB_ERR_OK; } /********************************************************************* * * Function : client_ua * * Description : Handle "ua-" headers properly. Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_ua(struct client_state *csp, char **header) { if ((csp->action->flags & ACTION_HIDE_USER_AGENT) != 0) { log_error(LOG_LEVEL_HEADER, "crunched User-Agent!"); freez(*header); } return JB_ERR_OK; } /********************************************************************* * * Function : client_from * * Description : Handle the "from" config setting properly. * Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_from(struct client_state *csp, char **header) { const char *newval; if ((csp->action->flags & ACTION_HIDE_FROM) == 0) { return JB_ERR_OK; } freez(*header); newval = csp->action->string[ACTION_STRING_FROM]; /* * Are we blocking the e-mail address? */ if ((newval == NULL) || (0 == strcmpic(newval, "block"))) { log_error(LOG_LEVEL_HEADER, "crunched From!"); return JB_ERR_OK; } log_error(LOG_LEVEL_HEADER, " modified"); *header = strdup("From: "); string_append(header, newval); return (*header == NULL) ? JB_ERR_MEMORY : JB_ERR_OK; } /********************************************************************* * * Function : client_send_cookie * * Description : Crunches the "cookie" header if necessary. * Called from `sed'. * * XXX: Stupid name, doesn't send squat. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_send_cookie(struct client_state *csp, char **header) { if (csp->action->flags & ACTION_CRUNCH_OUTGOING_COOKIES) { log_error(LOG_LEVEL_HEADER, "Crunched outgoing cookie: %s", *header); freez(*header); } return JB_ERR_OK; } /********************************************************************* * * Function : client_x_forwarded * * Description : Handle the "x-forwarded-for" config setting properly, * also used in the add_client_headers list. Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ jb_err client_x_forwarded(struct client_state *csp, char **header) { if (0 != (csp->action->flags & ACTION_CHANGE_X_FORWARDED_FOR)) { const char *parameter = csp->action->string[ACTION_STRING_CHANGE_X_FORWARDED_FOR]; if (0 == strcmpic(parameter, "block")) { freez(*header); log_error(LOG_LEVEL_HEADER, "crunched x-forwarded-for!"); } else if (0 == strcmpic(parameter, "add")) { string_append(header, ", "); string_append(header, csp->ip_addr_str); if (*header == NULL) { return JB_ERR_MEMORY; } log_error(LOG_LEVEL_HEADER, "Appended client IP address to %s", *header); csp->flags |= CSP_FLAG_X_FORWARDED_FOR_APPENDED; } else { log_error(LOG_LEVEL_FATAL, "Invalid change-x-forwarded-for parameter: '%s'", parameter); } } return JB_ERR_OK; } /********************************************************************* * * Function : client_max_forwards * * Description : If the HTTP method is OPTIONS or TRACE, subtract one * from the value of the Max-Forwards header field. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_max_forwards(struct client_state *csp, char **header) { int max_forwards; if ((0 == strcmpic(csp->http->gpc, "trace")) || (0 == strcmpic(csp->http->gpc, "options"))) { assert(*(*header+12) == ':'); if (1 == sscanf(*header+12, ": %d", &max_forwards)) { if (max_forwards > 0) { snprintf(*header, strlen(*header)+1, "Max-Forwards: %d", --max_forwards); log_error(LOG_LEVEL_HEADER, "Max-Forwards value for %s request reduced to %d.", csp->http->gpc, max_forwards); } else if (max_forwards < 0) { log_error(LOG_LEVEL_ERROR, "Crunching invalid header: %s", *header); freez(*header); } } else { log_error(LOG_LEVEL_ERROR, "Crunching invalid header: %s", *header); freez(*header); } } return JB_ERR_OK; } /********************************************************************* * * Function : client_host * * Description : If the request URI did not contain host and * port information, parse and evaluate the Host * header field. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_host(struct client_state *csp, char **header) { char *p, *q; if (!csp->http->hostport || (*csp->http->hostport == '*') || *csp->http->hostport == ' ' || *csp->http->hostport == '\0') { p = strdup_or_die((*header)+6); chomp(p); q = strdup_or_die(p); freez(csp->http->hostport); csp->http->hostport = p; freez(csp->http->host); csp->http->host = q; q = strchr(csp->http->host, ':'); if (q != NULL) { /* Terminate hostname and evaluate port string */ *q++ = '\0'; csp->http->port = atoi(q); } else { csp->http->port = csp->http->ssl ? 443 : 80; } log_error(LOG_LEVEL_HEADER, "New host and port from Host field: %s = %s:%d", csp->http->hostport, csp->http->host, csp->http->port); } /* Signal client_host_adder() to return right away */ csp->flags |= CSP_FLAG_HOST_HEADER_IS_SET; return JB_ERR_OK; } /********************************************************************* * * Function : client_if_modified_since * * Description : Remove or modify the If-Modified-Since header. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_if_modified_since(struct client_state *csp, char **header) { char newheader[50]; #ifdef HAVE_GMTIME_R struct tm gmt; #endif struct tm *timeptr = NULL; time_t tm = 0; const char *newval; char * endptr; if (0 == strcmpic(*header, "If-Modified-Since: Wed, 08 Jun 1955 12:00:00 GMT")) { /* * The client got an error message because of a temporary problem, * the problem is gone and the client now tries to revalidate our * error message on the real server. The revalidation would always * end with the transmission of the whole document and there is * no need to expose the bogus If-Modified-Since header. */ log_error(LOG_LEVEL_HEADER, "Crunching useless If-Modified-Since header."); freez(*header); } else if (csp->action->flags & ACTION_HIDE_IF_MODIFIED_SINCE) { newval = csp->action->string[ACTION_STRING_IF_MODIFIED_SINCE]; if ((0 == strcmpic(newval, "block"))) { log_error(LOG_LEVEL_HEADER, "Crunching %s", *header); freez(*header); } else /* add random value */ { const char *header_time = *header + sizeof("If-Modified-Since:"); if (JB_ERR_OK != parse_header_time(header_time, &tm)) { log_error(LOG_LEVEL_HEADER, "Couldn't parse: %s in %s (crunching!)", header_time, *header); freez(*header); } else { long int hours, minutes, seconds; long int rtime = strtol(newval, &endptr, 0); const int negative_range = (rtime < 0); if (rtime) { log_error(LOG_LEVEL_HEADER, "Randomizing: %s (random range: %d minut%s)", *header, rtime, (rtime == 1 || rtime == -1) ? "e": "es"); if (negative_range) { rtime *= -1; } rtime *= 60; rtime = pick_from_range(rtime); } else { log_error(LOG_LEVEL_ERROR, "Random range is 0. Assuming time transformation test.", *header); } tm += rtime * (negative_range ? -1 : 1); #ifdef HAVE_GMTIME_R timeptr = gmtime_r(&tm, &gmt); #elif defined(MUTEX_LOCKS_AVAILABLE) privoxy_mutex_lock(&gmtime_mutex); timeptr = gmtime(&tm); privoxy_mutex_unlock(&gmtime_mutex); #else timeptr = gmtime(&tm); #endif if ((NULL == timeptr) || !strftime(newheader, sizeof(newheader), "%a, %d %b %Y %H:%M:%S GMT", timeptr)) { log_error(LOG_LEVEL_ERROR, "Randomizing '%s' failed. Crunching the header without replacement.", *header); freez(*header); return JB_ERR_OK; } freez(*header); *header = strdup("If-Modified-Since: "); string_append(header, newheader); if (*header == NULL) { log_error(LOG_LEVEL_HEADER, "Insufficient memory, header crunched without replacement."); return JB_ERR_MEMORY; } hours = rtime / 3600; minutes = rtime / 60 % 60; seconds = rtime % 60; log_error(LOG_LEVEL_HEADER, "Randomized: %s (%s %d hou%s %d minut%s %d second%s", *header, (negative_range) ? "subtracted" : "added", hours, (hours == 1) ? "r" : "rs", minutes, (minutes == 1) ? "e" : "es", seconds, (seconds == 1) ? ")" : "s)"); } } } return JB_ERR_OK; } /********************************************************************* * * Function : client_if_none_match * * Description : Remove the If-None-Match header. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_if_none_match(struct client_state *csp, char **header) { if (csp->action->flags & ACTION_CRUNCH_IF_NONE_MATCH) { log_error(LOG_LEVEL_HEADER, "Crunching %s", *header); freez(*header); } return JB_ERR_OK; } /********************************************************************* * * Function : client_x_filter * * Description : Disables filtering if the client set "X-Filter: No". * Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success * *********************************************************************/ jb_err client_x_filter(struct client_state *csp, char **header) { if (0 == strcmpic(*header, "X-Filter: No")) { if (!(csp->config->feature_flags & RUNTIME_FEATURE_HTTP_TOGGLE)) { log_error(LOG_LEVEL_INFO, "Ignored the client's request to fetch without filtering."); } else { if (csp->action->flags & ACTION_FORCE_TEXT_MODE) { log_error(LOG_LEVEL_HEADER, "force-text-mode overruled the client's request to fetch without filtering!"); } else { csp->content_type = CT_TABOO; /* XXX: This hack shouldn't be necessary */ csp->flags |= CSP_FLAG_NO_FILTERING; log_error(LOG_LEVEL_HEADER, "Accepted the client's request to fetch without filtering."); } log_error(LOG_LEVEL_HEADER, "Crunching %s", *header); freez(*header); } } return JB_ERR_OK; } /********************************************************************* * * Function : client_range * * Description : Removes Range, Request-Range and If-Range headers if * content filtering is enabled and the range doesn't * start at byte 0. * * If the client's version of the document has been * altered by Privoxy, the server could interpret the * range differently than the client intended in which * case the user could end up with corrupted content. * * If the range starts at byte 0 this isn't an issue * so the header can pass. Partial requests like this * are used to render preview images for videos without * downloading the whole video. * * While HTTP doesn't require that range requests are * honoured and the client could simply abort the download * after receiving a sufficient amount of data, various * clients don't handle complete responses to range * requests gracefully and emit misleading error messages * instead. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK * *********************************************************************/ static jb_err client_range(struct client_state *csp, char **header) { if (content_filters_enabled(csp->action) && (0 != strncmpic(strstr(*header, ":"), ": bytes=0-", 10))) { log_error(LOG_LEVEL_HEADER, "Content filtering is enabled." " Crunching: \'%s\' to prevent range-mismatch problems.", *header); freez(*header); } return JB_ERR_OK; } /* the following functions add headers directly to the header list */ /********************************************************************* * * Function : client_host_adder * * Description : Adds the Host: header field if it is missing. * Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_host_adder(struct client_state *csp) { char *p; jb_err err; if (csp->flags & CSP_FLAG_HOST_HEADER_IS_SET) { /* Header already set by the client, nothing to do. */ return JB_ERR_OK; } if (!csp->http->hostport || !*(csp->http->hostport)) { /* XXX: When does this happen and why is it OK? */ log_error(LOG_LEVEL_INFO, "Weirdness in client_host_adder detected and ignored."); return JB_ERR_OK; } /* * remove 'user:pass@' from 'proto://user:pass@host' */ if ((p = strchr( csp->http->hostport, '@')) != NULL) { p++; } else { p = csp->http->hostport; } /* XXX: Just add it, we already made sure that it will be unique */ log_error(LOG_LEVEL_HEADER, "addh-unique: Host: %s", p); err = enlist_unique_header(csp->headers, "Host", p); return err; } /********************************************************************* * * Function : client_xtra_adder * * Description : Used in the add_client_headers list. Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_xtra_adder(struct client_state *csp) { struct list_entry *lst; jb_err err; for (lst = csp->action->multi[ACTION_MULTI_ADD_HEADER]->first; lst ; lst = lst->next) { log_error(LOG_LEVEL_HEADER, "addh: %s", lst->str); err = enlist(csp->headers, lst->str); if (err) { return err; } } return JB_ERR_OK; } /********************************************************************* * * Function : client_x_forwarded_for_adder * * Description : Used in the add_client_headers list. Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_x_forwarded_for_adder(struct client_state *csp) { char *header = NULL; jb_err err; if (!((csp->action->flags & ACTION_CHANGE_X_FORWARDED_FOR) && (0 == strcmpic(csp->action->string[ACTION_STRING_CHANGE_X_FORWARDED_FOR], "add"))) || (csp->flags & CSP_FLAG_X_FORWARDED_FOR_APPENDED)) { /* * If we aren't adding X-Forwarded-For headers, * or we already appended an existing X-Forwarded-For * header, there's nothing left to do here. */ return JB_ERR_OK; } header = strdup("X-Forwarded-For: "); string_append(&header, csp->ip_addr_str); if (header == NULL) { return JB_ERR_MEMORY; } log_error(LOG_LEVEL_HEADER, "addh: %s", header); err = enlist(csp->headers, header); freez(header); return err; } /********************************************************************* * * Function : server_connection_adder * * Description : Adds an appropriate "Connection:" header to csp->headers * unless the header was already present. Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err server_connection_adder(struct client_state *csp) { const unsigned int flags = csp->flags; const char *response_status_line = csp->headers->first->str; static const char connection_close[] = "Connection: close"; if ((flags & CSP_FLAG_CLIENT_HEADER_PARSING_DONE) && (flags & CSP_FLAG_SERVER_CONNECTION_HEADER_SET)) { return JB_ERR_OK; } /* * XXX: if we downgraded the response, this check will fail. */ if ((csp->config->feature_flags & RUNTIME_FEATURE_CONNECTION_KEEP_ALIVE) && (NULL != response_status_line) && !strncmpic(response_status_line, "HTTP/1.1", 8) #ifdef FEATURE_CONNECTION_KEEP_ALIVE && !(csp->flags & CSP_FLAG_SERVER_SOCKET_TAINTED) #endif ) { log_error(LOG_LEVEL_HEADER, "A HTTP/1.1 response " "without Connection header implies keep-alive."); csp->flags |= CSP_FLAG_SERVER_CONNECTION_KEEP_ALIVE; return JB_ERR_OK; } log_error(LOG_LEVEL_HEADER, "Adding: %s", connection_close); return enlist(csp->headers, connection_close); } #ifdef FEATURE_CONNECTION_KEEP_ALIVE /********************************************************************* * * Function : server_proxy_connection_adder * * Description : Adds a "Proxy-Connection: keep-alive" header to * csp->headers when appropriate. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err server_proxy_connection_adder(struct client_state *csp) { static const char proxy_connection_header[] = "Proxy-Connection: keep-alive"; jb_err err = JB_ERR_OK; if ((csp->flags & CSP_FLAG_CLIENT_CONNECTION_KEEP_ALIVE) && !(csp->flags & CSP_FLAG_SERVER_SOCKET_TAINTED) && !(csp->flags & CSP_FLAG_SERVER_PROXY_CONNECTION_HEADER_SET) && ((csp->flags & CSP_FLAG_SERVER_CONTENT_LENGTH_SET) || (csp->flags & CSP_FLAG_CHUNKED))) { log_error(LOG_LEVEL_HEADER, "Adding: %s", proxy_connection_header); err = enlist(csp->headers, proxy_connection_header); } return err; } #endif /* FEATURE_CONNECTION_KEEP_ALIVE */ /********************************************************************* * * Function : client_connection_header_adder * * Description : Adds a proper "Connection:" header to csp->headers * unless the header was already present. Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err client_connection_header_adder(struct client_state *csp) { static const char connection_close[] = "Connection: close"; if (!(csp->flags & CSP_FLAG_CLIENT_HEADER_PARSING_DONE) && (csp->flags & CSP_FLAG_CLIENT_CONNECTION_HEADER_SET)) { return JB_ERR_OK; } #ifdef FEATURE_CONNECTION_KEEP_ALIVE if ((csp->config->feature_flags & RUNTIME_FEATURE_CONNECTION_KEEP_ALIVE) && !(csp->flags & CSP_FLAG_SERVER_SOCKET_TAINTED) && (csp->http->ssl == 0) && !strcmpic(csp->http->ver, "HTTP/1.1")) { csp->flags |= CSP_FLAG_CLIENT_CONNECTION_KEEP_ALIVE; return JB_ERR_OK; } #endif /* FEATURE_CONNECTION_KEEP_ALIVE */ log_error(LOG_LEVEL_HEADER, "Adding: %s", connection_close); return enlist(csp->headers, connection_close); } /********************************************************************* * * Function : server_http * * Description : - Save the HTTP Status into csp->http->status * - Set CT_TABOO to prevent filtering if the answer * is a partial range (HTTP status 206) * - Rewrite HTTP/1.1 answers to HTTP/1.0 if +downgrade * action applies. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err server_http(struct client_state *csp, char **header) { sscanf(*header, "HTTP/%*d.%*d %d", &(csp->http->status)); if (csp->http->status == 206) { csp->content_type = CT_TABOO; } if ((csp->action->flags & ACTION_DOWNGRADE) != 0) { /* XXX: Should we do a real validity check here? */ if (strlen(*header) > 8) { (*header)[7] = '0'; log_error(LOG_LEVEL_HEADER, "Downgraded answer to HTTP/1.0"); } else { /* * XXX: Should we block the request or * enlist a valid status code line here? */ log_error(LOG_LEVEL_INFO, "Malformed server response detected. " "Downgrading to HTTP/1.0 impossible."); } } return JB_ERR_OK; } /********************************************************************* * * Function : add_cooky_expiry_date * * Description : Adds a cookie expiry date to a string. * * Parameters : * 1 : cookie = On input, pointer to cookie to modify. * On output, pointer to the modified header. * The original string is freed. * 2 : lifetime = Seconds the cookie should be valid * * Returns : N/A * *********************************************************************/ static void add_cookie_expiry_date(char **cookie, time_t lifetime) { char tmp[50]; struct tm *timeptr = NULL; time_t expiry_date = time(NULL) + lifetime; #ifdef HAVE_GMTIME_R struct tm gmt; timeptr = gmtime_r(&expiry_date, &gmt); #elif defined(MUTEX_LOCKS_AVAILABLE) privoxy_mutex_lock(&gmtime_mutex); timeptr = gmtime(&expiry_date); privoxy_mutex_unlock(&gmtime_mutex); #else timeptr = gmtime(&expiry_date); #endif if (NULL == timeptr) { log_error(LOG_LEVEL_FATAL, "Failed to get the time in add_cooky_expiry_date()"); } strftime(tmp, sizeof(tmp), "; expires=%a, %d-%b-%Y %H:%M:%S GMT", timeptr); if (JB_ERR_OK != string_append(cookie, tmp)) { log_error(LOG_LEVEL_FATAL, "Out of memory in add_cooky_expiry()"); } } /********************************************************************* * * Function : server_set_cookie * * Description : Handle the server "cookie" header properly. * Crunch, accept or rewrite it to a session cookie. * Called from `sed'. * * Parameters : * 1 : csp = Current client state (buffers, headers, etc...) * 2 : header = On input, pointer to header to modify. * On output, pointer to the modified header, or NULL * to remove the header. This function frees the * original string if necessary. * * Returns : JB_ERR_OK on success, or * JB_ERR_MEMORY on out-of-memory error. * *********************************************************************/ static jb_err server_set_cookie(struct client_state *csp, char **header) { if ((csp->action->flags & ACTION_CRUNCH_INCOMING_COOKIES) != 0) { log_error(LOG_LEVEL_HEADER, "Crunching incoming cookie: %s", *header); freez(*header); } else if ((0 != (csp->action->flags & ACTION_SESSION_COOKIES_ONLY)) || (0 != (csp->action->flags & ACTION_LIMIT_COOKIE_LIFETIME))) { time_t now; time_t cookie_time; long cookie_lifetime = 0; enum { NO_EXPIRY_DATE_SPECIFIED, EXPIRY_DATE_ACCEPTABLE, EXPIRY_DATE_UNACCEPTABLE } expiry_date_status = NO_EXPIRY_DATE_SPECIFIED; /* A variable to store the tag we're working on */ char *cur_tag; /* Skip "Set-Cookie:" (11 characters) in header */ cur_tag = *header + 11; /* skip whitespace between "Set-Cookie:" and value */ while (*cur_tag && privoxy_isspace(*cur_tag)) { cur_tag++; } time(&now); if ((csp->action->flags & ACTION_LIMIT_COOKIE_LIFETIME) != 0) { const char *param = csp->action->string[ACTION_STRING_LIMIT_COOKIE_LIFETIME]; cookie_lifetime = strtol(param, NULL, 0); if (cookie_lifetime < 0) { log_error(LOG_LEVEL_FATAL, "Invalid cookie lifetime limit: %s", param); } cookie_lifetime *= 60; } /* Loop through each tag in the cookie */ while (*cur_tag) { /* Find next tag */ char *next_tag = strchr(cur_tag, ';'); if (next_tag != NULL) { /* Skip the ';' character itself */ next_tag++; /* skip whitespace ";" and start of tag */ while (*next_tag && privoxy_isspace(*next_tag)) { next_tag++; } } else { /* "Next tag" is the end of the string */ next_tag = cur_tag + strlen(cur_tag); } /* * Check the expiration date to see * if the cookie is still valid, if yes, * rewrite it to a session cookie. */ if ((strncmpic(cur_tag, "expires=", 8) == 0) && *(cur_tag + 8)) { char *expiration_date = cur_tag + 8; /* Skip "[Ee]xpires=" */ if ((expiration_date[0] == '"') && (expiration_date[1] != '\0')) { /* * Skip quotation mark. RFC 2109 10.1.2 seems to hint * that the expiration date isn't supposed to be quoted, * but some servers do it anyway. */ expiration_date++; } /* Did we detect the date properly? */ if (JB_ERR_OK != parse_header_time(expiration_date, &cookie_time)) { /* * Nope, treat it as if it was still valid. * * XXX: Should we remove the whole cookie instead? */ log_error(LOG_LEVEL_ERROR, "Can't parse \'%s\', send by %s. Unsupported time format?", cur_tag, csp->http->url); string_move(cur_tag, next_tag); expiry_date_status = EXPIRY_DATE_UNACCEPTABLE; } else { /* * Yes. Check if the cookie is still valid. * * If the cookie is already expired it's probably * a delete cookie and even if it isn't, the browser * will discard it anyway. */ /* * XXX: timegm() isn't available on some AmigaOS * versions and our replacement doesn't work. * * Our options are to either: * * - disable session-cookies-only completely if timegm * is missing, * * - to simply remove all expired tags, like it has * been done until Privoxy 3.0.6 and to live with * the consequence that it can cause login/logout * problems on servers that don't validate their * input properly, or * * - to replace it with mktime in which * case there is a slight chance of valid cookies * passing as already expired. * * This is the way it's currently done and it's not * as bad as it sounds. If the missing GMT offset is * enough to change the result of the expiration check * the cookie will be only valid for a few hours * anyway, which in many cases will be shorter * than a browser session. */ if (cookie_time < now) { log_error(LOG_LEVEL_HEADER, "Cookie \'%s\' is already expired and can pass unmodified.", *header); /* Just in case some clown sets more then one expiration date */ cur_tag = next_tag; expiry_date_status = EXPIRY_DATE_ACCEPTABLE; } else if ((cookie_lifetime != 0) && (cookie_time < (now + cookie_lifetime))) { log_error(LOG_LEVEL_HEADER, "Cookie \'%s\' can pass unmodified. " "Its lifetime is below the limit.", *header); /* Just in case some clown sets more then one expiration date */ cur_tag = next_tag; expiry_date_status = EXPIRY_DATE_ACCEPTABLE; } else { /* * Still valid, delete expiration date by copying * the rest of the string over it. */ string_move(cur_tag, next_tag); /* That changed the header, need to issue a log message */ expiry_date_status = EXPIRY_DATE_UNACCEPTABLE; /* * Note that the next tag has now been moved to *cur_tag, * so we do not need to update the cur_tag pointer. */ } } } else { /* Move on to next cookie tag */ cur_tag = next_tag; } } if (expiry_date_status != EXPIRY_DATE_ACCEPTABLE) { assert(NULL != *header); if (cookie_lifetime != 0) { add_cookie_expiry_date(header, cookie_lifetime); log_error(LOG_LEVEL_HEADER, "Cookie rewritten to: %s", *header); } else if (expiry_date_status != NO_EXPIRY_DATE_SPECIFIED) { log_error(LOG_LEVEL_HEADER, "Cookie rewritten to a temporary one: %s", *header); } } } return JB_ERR_OK; } #ifdef FEATURE_FORCE_LOAD /********************************************************************* * * Function : strclean * * Description : In-Situ-Eliminate all occurrences of substring in * string * * Parameters : * 1 : string = string to clean * 2 : substring = substring to eliminate * * Returns : Number of eliminations * *********************************************************************/ int strclean(char *string, const char *substring) { int hits = 0; size_t len; char *pos, *p; len = strlen(substring); while((pos = strstr(string, substring)) != NULL) { p = pos + len; do { *(p - len) = *p; } while (*p++ != '\0'); hits++; } return(hits); } #endif /* def FEATURE_FORCE_LOAD */ /********************************************************************* * * Function : parse_header_time * * Description : Parses time formats used in HTTP header strings * to get the numerical respresentation. * * Parameters : * 1 : header_time = HTTP header time as string. * 2 : result = storage for header_time in seconds * * Returns : JB_ERR_OK if the time format was recognized, or * JB_ERR_PARSE otherwise. * *********************************************************************/ static jb_err parse_header_time(const char *header_time, time_t *result) { struct tm gmt; /* * Checking for two-digit years first in an * attempt to work around GNU libc's strptime() * reporting negative year values when using %Y. */ static const char time_formats[][22] = { /* Tue, 02-Jun-37 20:00:00 */ "%a, %d-%b-%y %H:%M:%S", /* Tue, 02 Jun 2037 20:00:00 */ "%a, %d %b %Y %H:%M:%S", /* Tue, 02-Jun-2037 20:00:00 */ "%a, %d-%b-%Y %H:%M:%S", /* Tuesday, 02-Jun-2037 20:00:00 */ "%A, %d-%b-%Y %H:%M:%S", /* Tuesday Jun 02 20:00:00 2037 */ "%A %b %d %H:%M:%S %Y" }; unsigned int i; for (i = 0; i < SZ(time_formats); i++) { /* * Zero out gmt to prevent time zone offsets. * Documented to be required for GNU libc. */ memset(&gmt, 0, sizeof(gmt)); if (NULL != strptime(header_time, time_formats[i], &gmt)) { /* Sanity check for GNU libc. */ if (gmt.tm_year < 0) { log_error(LOG_LEVEL_HEADER, "Failed to parse '%s' using '%s'. Moving on.", header_time, time_formats[i]); continue; } *result = timegm(&gmt); #ifdef FEATURE_STRPTIME_SANITY_CHECKS /* * Verify that parsing the date recreated from the first * parse operation gets the previous result. If it doesn't, * either strptime() or strftime() are malfunctioning. * * We could string-compare the recreated date with the original * header date, but this leads to false positives as strptime() * may let %a accept all day formats while strftime() will only * create one. */ { char recreated_date[100]; struct tm *tm; time_t result2; tm = gmtime(result); strftime(recreated_date, sizeof(recreated_date), time_formats[i], tm); memset(&gmt, 0, sizeof(gmt)); if (NULL == strptime(recreated_date, time_formats[i], &gmt)) { log_error(LOG_LEVEL_ERROR, "Failed to parse '%s' generated with '%s' to recreate '%s'.", recreated_date, time_formats[i], header_time); continue; } result2 = timegm(&gmt); if (*result != result2) { log_error(LOG_LEVEL_ERROR, "strftime() and strptime() disagree. " "Format: '%s'. In: '%s', out: '%s'. %d != %d. Rejecting.", time_formats[i], header_time, recreated_date, *result, result2); continue; } } #endif return JB_ERR_OK; } } return JB_ERR_PARSE; } /********************************************************************* * * Function : get_destination_from_headers * * Description : Parse the "Host:" header to get the request's destination. * Only needed if the client's request was forcefully * redirected into Privoxy. * * Code mainly copied from client_host() which is currently * run too late for this purpose. * * Parameters : * 1 : headers = List of headers (one of them hopefully being * the "Host:" header) * 2 : http = storage for the result (host, port and hostport). * * Returns : JB_ERR_MEMORY (or terminates) in case of memory problems, * JB_ERR_PARSE if the host header couldn't be found, * JB_ERR_OK otherwise. * *********************************************************************/ jb_err get_destination_from_headers(const struct list *headers, struct http_request *http) { char *q; char *p; char *host; host = get_header_value(headers, "Host:"); if (NULL == host) { log_error(LOG_LEVEL_ERROR, "No \"Host:\" header found."); return JB_ERR_PARSE; } p = strdup_or_die(host); chomp(p); q = strdup_or_die(p); freez(http->hostport); http->hostport = p; freez(http->host); http->host = q; q = strchr(http->host, ':'); if (q != NULL) { /* Terminate hostname and evaluate port string */ *q++ = '\0'; http->port = atoi(q); } else { http->port = http->ssl ? 443 : 80; } /* Rebuild request URL */ freez(http->url); http->url = strdup(http->ssl ? "https://" : "http://"); string_append(&http->url, http->hostport); string_append(&http->url, http->path); if (http->url == NULL) { return JB_ERR_MEMORY; } log_error(LOG_LEVEL_HEADER, "Destination extracted from \"Host:\" header. New request URL: %s", http->url); return JB_ERR_OK; } /********************************************************************* * * Function : create_forged_referrer * * Description : Helper for client_referrer to forge a referer as * 'http://hostname[:port]/' to fool stupid * checks for in-site links * * Parameters : * 1 : header = Pointer to header pointer * 2 : hostport = Host and optionally port as string * * Returns : JB_ERR_OK in case of success, or * JB_ERR_MEMORY in case of memory problems. * *********************************************************************/ static jb_err create_forged_referrer(char **header, const char *hostport) { assert(NULL == *header); *header = strdup("Referer: http://"); string_append(header, hostport); string_append(header, "/"); if (NULL == *header) { return JB_ERR_MEMORY; } log_error(LOG_LEVEL_HEADER, "Referer forged to: %s", *header); return JB_ERR_OK; } /********************************************************************* * * Function : create_fake_referrer * * Description : Helper for client_referrer to create a fake referrer * based on a string supplied by the user. * * Parameters : * 1 : header = Pointer to header pointer * 2 : hosthost = Referrer to fake * * Returns : JB_ERR_OK in case of success, or * JB_ERR_MEMORY in case of memory problems. * *********************************************************************/ static jb_err create_fake_referrer(char **header, const char *fake_referrer) { assert(NULL == *header); if ((0 != strncmpic(fake_referrer, "http://", 7)) && (0 != strncmpic(fake_referrer, "https://", 8))) { log_error(LOG_LEVEL_HEADER, "Parameter: +hide-referrer{%s} is a bad idea, but I don't care.", fake_referrer); } *header = strdup("Referer: "); string_append(header, fake_referrer); if (NULL == *header) { return JB_ERR_MEMORY; } log_error(LOG_LEVEL_HEADER, "Referer replaced with: %s", *header); return JB_ERR_OK; } /********************************************************************* * * Function : handle_conditional_hide_referrer_parameter * * Description : Helper for client_referrer to crunch or forge * the referrer header if the host has changed. * * Parameters : * 1 : header = Pointer to header pointer * 2 : host = The target host (may include the port) * 3 : parameter_conditional_block = Boolean to signal * if we're in conditional-block mode. If not set, * we're in conditional-forge mode. * * Returns : JB_ERR_OK in case of success, or * JB_ERR_MEMORY in case of memory problems. * *********************************************************************/ static jb_err handle_conditional_hide_referrer_parameter(char **header, const char *host, const int parameter_conditional_block) { char *referer = strdup_or_die(*header); const size_t hostlength = strlen(host); const char *referer_url = NULL; /* referer begins with 'Referer: http[s]://' */ if ((hostlength+17) < strlen(referer)) { /* * Shorten referer to make sure the referer is blocked * if www.example.org/www.example.com-shall-see-the-referer/ * links to www.example.com/ */ referer[hostlength+17] = '\0'; } referer_url = strstr(referer, "http://"); if ((NULL == referer_url) || (NULL == strstr(referer_url, host))) { /* Host has changed, Referer is invalid or a https URL. */ if (parameter_conditional_block) { log_error(LOG_LEVEL_HEADER, "New host is: %s. Crunching %s!", host, *header); freez(*header); } else { freez(*header); freez(referer); return create_forged_referrer(header, host); } } freez(referer); return JB_ERR_OK; } /********************************************************************* * * Function : create_content_length_header * * Description : Creates a Content-Length header. * * Parameters : * 1 : content_length = The content length to be used in the header. * 2 : header = Allocated space to safe the header. * 3 : buffer_length = The length of the allocated space. * * Returns : void * *********************************************************************/ static void create_content_length_header(unsigned long long content_length, char *header, size_t buffer_length) { snprintf(header, buffer_length, "Content-Length: %llu", content_length); } #ifdef FEATURE_CONNECTION_KEEP_ALIVE /********************************************************************* * * Function : get_expected_content_length * * Description : Figures out the content length from a list of headers. * * Parameters : * 1 : headers = List of headers * * Returns : Number of bytes to expect * *********************************************************************/ unsigned long long get_expected_content_length(struct list *headers) { const char *content_length_header; unsigned long long content_length = 0; content_length_header = get_header_value(headers, "Content-Length:"); if (content_length_header != NULL) { if (JB_ERR_OK != get_content_length(content_length_header, &content_length)) { log_error(LOG_LEVEL_ERROR, "Failed to get the Content-Length in %s", content_length_header); /* XXX: The header will be removed later on */ return 0; } } return content_length; } #endif /* Local Variables: tab-width: 3 end: */