X-Git-Url: http://www.privoxy.org/gitweb/?p=privoxy.git;a=blobdiff_plain;f=pcrs.c;h=83100983b6475d0b7d75cbae6280db8595227d28;hp=f48e3dae09f73a96b35b9379065c43d8b438baa9;hb=56f3964a2bd367ca422feef5c72f537aa43c17e8;hpb=d31bd7fabbfa586b5905df0eb3e0e32e76895555 diff --git a/pcrs.c b/pcrs.c index f48e3dae..83100983 100644 --- a/pcrs.c +++ b/pcrs.c @@ -1,33 +1,21 @@ -const char pcrs_rcs[] = "$Id: pcrs.c,v 1.6 2001/06/03 19:12:45 oes Exp $"; - /********************************************************************* * * File : $Source: /cvsroot/ijbswa/current/pcrs.c,v $ * - * Purpose : This is the alpha release of libpcrs. It is only published - * at this early stage of development, because it is - * needed for a new feature in JunkBuster. - * - * While no inconsistencies, memory leaks or functional bugs - * are known at this time, there *could* be plenty ;-). Also, - * Many pcre-specific options are not yet supported, and - * error handling needs improvement. - * - * pcrs is a supplement to the brilliant pcre library by Philip - * Hazel (ph10@cam.ac.uk) and adds Perl-style substitution. That - * is, it mimics Perl's 's' operator. + * Purpose : pcrs is a supplement to the pcre library by Philip Hazel + * and adds Perl-style substitution. That + * is, it mimics Perl's 's' operator. See pcrs(3) for details. * - * Currently, there's no documentation besides comments and the - * source itself ;-) - * - * Short note: I addition to perl's options, 'U' for ungreedy - * and 't' for trivial (i.e.: ignore backrefs in the substitute) - * are supported. + * WARNING: This file contains additional functions and bug + * fixes that aren't part of the latest official pcrs package + * (which apparently is no longer maintained). * * Copyright : Written and Copyright (C) 2000, 2001 by Andreas S. Oesterhelt * * - * This program is free software; you can redistribute it + * Copyright (C) 2006, 2007 Fabian Keil + * + * 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 @@ -45,100 +33,106 @@ const char pcrs_rcs[] = "$Id: pcrs.c,v 1.6 2001/06/03 19:12:45 oes Exp $"; * or write to the Free Software Foundation, Inc., 59 * Temple Place - Suite 330, Boston, MA 02111-1307, USA. * - * Revisions : - * $Log: pcrs.c,v $ - * Revision 1.6 2001/06/03 19:12:45 oes - * added FIXME - * - * Revision 1.5 2001/05/29 09:50:24 jongfoster - * Unified blocklist/imagelist/permissionslist. - * File format is still under discussion, but the internal changes - * are (mostly) done. - * - * Also modified interceptor behaviour: - * - We now intercept all URLs beginning with one of the following - * prefixes (and *only* these prefixes): - * * http://i.j.b/ - * * http://ijbswa.sf.net/config/ - * * http://ijbswa.sourceforge.net/config/ - * - New interceptors "home page" - go to http://i.j.b/ to see it. - * - Internal changes so that intercepted and fast redirect pages - * are not replaced with an image. - * - Interceptors now have the option to send a binary page direct - * to the client. (i.e. ijb-send-banner uses this) - * - Implemented show-url-info interceptor. (Which is why I needed - * the above interceptors changes - a typical URL is - * "http://i.j.b/show-url-info?url=www.somesite.com/banner.gif". - * The previous mechanism would not have intercepted that, and - * if it had been intercepted then it then it would have replaced - * it with an image.) - * - * Revision 1.4 2001/05/25 14:12:40 oes - * Fixed bug: Empty substitutes now detected - * - * Revision 1.3 2001/05/25 11:03:55 oes - * Added sanity check for NULL jobs to pcrs_exec_substitution - * - * Revision 1.2 2001/05/22 18:46:04 oes - * - * - Enabled filtering banners by size rather than URL - * by adding patterns that replace all standard banner - * sizes with the "Junkbuster" gif to the re_filterfile - * - * - Enabled filtering WebBugs by providing a pattern - * which kills all 1x1 images - * - * - Added support for PCRE_UNGREEDY behaviour to pcrs, - * which is selected by the (nonstandard and therefore - * capital) letter 'U' in the option string. - * It causes the quantifiers to be ungreedy by default. - * Appending a ? turns back to greedy (!). - * - * - Added a new interceptor ijb-send-banner, which - * sends back the "Junkbuster" gif. Without imagelist or - * MSIE detection support, or if tinygif = 1, or the - * URL isn't recognized as an imageurl, a lame HTML - * explanation is sent instead. - * - * - Added new feature, which permits blocking remote - * script redirects and firing back a local redirect - * to the browser. - * The feature is conditionally compiled, i.e. it - * can be disabled with --disable-fast-redirects, - * plus it must be activated by a "fast-redirects" - * line in the config file, has its own log level - * and of course wants to be displayed by show-proxy-args - * Note: Boy, all the #ifdefs in 1001 locations and - * all the fumbling with configure.in and acconfig.h - * were *way* more work than the feature itself :-( - * - * - Because a generic redirect template was needed for - * this, tinygif = 3 now uses the same. - * - * - Moved GIFs, and other static HTTP response templates - * to project.h - * - * - Some minor fixes - * - * - Removed some >400 CRs again (Jon, you really worked - * a lot! ;-) - * - * Revision 1.1.1.1 2001/05/15 13:59:02 oes - * Initial import of version 2.9.3 source tree - * - * *********************************************************************/ - -#include + #include +#include +#include + +/* + * Include project.h just so that the right pcre.h gets + * included from there + */ +#include "project.h" + +/* For snprintf only */ +#include "miscutil.h" +/* For xtoi */ +#include "encode.h" + #include "pcrs.h" -const char pcrs_h_rcs[] = PCRS_H_VERSION; +/* + * Internal prototypes + */ + +static int pcrs_parse_perl_options(const char *optstring, int *flags); +static pcrs_substitute *pcrs_compile_replacement(const char *replacement, int trivialflag, + int capturecount, int *errptr); +static int is_hex_sequence(const char *sequence); /********************************************************************* * - * Function : pcrs_compile_perl_options + * Function : pcrs_strerror + * + * Description : Return a string describing a given error code. + * + * Parameters : + * 1 : error = the error code + * + * Returns : char * to the descriptive string + * + *********************************************************************/ +const char *pcrs_strerror(const int error) +{ + static char buf[100]; + + if (error != 0) + { + switch (error) + { + /* Passed-through PCRE error: */ + case PCRE_ERROR_NOMEMORY: return "(pcre:) No memory"; + + /* Shouldn't happen unless PCRE or PCRS bug, or user messed with compiled job: */ + case PCRE_ERROR_NULL: return "(pcre:) NULL code or subject or ovector"; + case PCRE_ERROR_BADOPTION: return "(pcre:) Unrecognized option bit"; + case PCRE_ERROR_BADMAGIC: return "(pcre:) Bad magic number in code"; + case PCRE_ERROR_UNKNOWN_NODE: return "(pcre:) Bad node in pattern"; + + /* Can't happen / not passed: */ + case PCRE_ERROR_NOSUBSTRING: return "(pcre:) Fire in power supply"; + case PCRE_ERROR_NOMATCH: return "(pcre:) Water in power supply"; + +#ifdef PCRE_ERROR_MATCHLIMIT + /* + * Only reported by PCRE versions newer than our own. + */ + case PCRE_ERROR_MATCHLIMIT: return "(pcre:) Match limit reached"; +#endif /* def PCRE_ERROR_MATCHLIMIT */ + + /* PCRS errors: */ + case PCRS_ERR_NOMEM: return "(pcrs:) No memory"; + case PCRS_ERR_CMDSYNTAX: return "(pcrs:) Syntax error while parsing command"; + case PCRS_ERR_STUDY: return "(pcrs:) PCRE error while studying the pattern"; + case PCRS_ERR_BADJOB: return "(pcrs:) Bad job - NULL job, pattern or substitute"; + case PCRS_WARN_BADREF: return "(pcrs:) Backreference out of range"; + case PCRS_WARN_TRUNCATION: + return "(pcrs:) At least one variable was too big and has been truncated before compilation"; + + /* + * XXX: With the exception of PCRE_ERROR_MATCHLIMIT we + * only catch PCRE errors that can happen with our internal + * version. If Privoxy is linked against a newer + * PCRE version all bets are off ... + */ + default: + snprintf(buf, sizeof(buf), + "Error code %d. For details, check the pcre documentation.", + error); + return buf; + } + } + /* error >= 0: No error */ + return "(pcrs:) Everything's just fine. Thanks for asking."; + +} + + +/********************************************************************* + * + * Function : pcrs_parse_perl_options * * Description : This function parses a string containing the options to * Perl's s/// operator. It returns an integer that is the @@ -147,33 +141,37 @@ const char pcrs_h_rcs[] = PCRS_H_VERSION; * 'T' (trivial) options but pcrs needs them, the corresponding * flags are set if 'g'or 'T' is encountered. * Note: The 'T' and 'U' options do not conform to Perl. - * + * * Parameters : * 1 : optstring = string with options in perl syntax * 2 : flags = see description * - * Returns : option integer suitable for pcre + * Returns : option integer suitable for pcre * *********************************************************************/ -int pcrs_compile_perl_options(char *optstring, int *flags) +static int pcrs_parse_perl_options(const char *optstring, int *flags) { size_t i; int rc = 0; *flags = 0; - for (i=0; i < strlen(optstring); i++) + + if (NULL == optstring) return 0; + + for (i = 0; i < strlen(optstring); i++) { switch(optstring[i]) { - case 'e': break; + case 'e': break; /* ToDo ;-) */ case 'g': *flags |= PCRS_GLOBAL; break; case 'i': rc |= PCRE_CASELESS; break; case 'm': rc |= PCRE_MULTILINE; break; case 'o': break; case 's': rc |= PCRE_DOTALL; break; case 'x': rc |= PCRE_EXTENDED; break; + case 'D': *flags |= PCRS_DYNAMIC; break; case 'U': rc |= PCRE_UNGREEDY; break; - case 'T': *flags |= PCRS_TRIVIAL; break; - default: break; + case 'T': *flags |= PCRS_TRIVIAL; break; + default: break; } } return rc; @@ -181,6 +179,38 @@ int pcrs_compile_perl_options(char *optstring, int *flags) } +#ifdef FUZZ +/********************************************************************* + * + * Function : pcrs_compile_fuzzed_replacement + * + * Description : Wrapper around pcrs_compile_replacement() for + * fuzzing purposes. + * + * Parameters : + * 1 : replacement = replacement part of s/// operator + * in perl syntax + * 2 : errptr = pointer to an integer in which error + * conditions can be returned. + * + * Returns : pcrs_substitute data structure, or NULL if an + * error is encountered. In that case, *errptr has + * the reason. + * + *********************************************************************/ +extern pcrs_substitute *pcrs_compile_fuzzed_replacement(const char *replacement, int *errptr) +{ + int capturecount = PCRS_MAX_SUBMATCHES; /* XXX: fuzzworthy? */ + int trivial_flag = 0; /* We don't want to fuzz strncpy() */ + + *errptr = 0; /* XXX: Should pcrs_compile_replacement() do this? */ + + return pcrs_compile_replacement(replacement, trivial_flag, capturecount, errptr); + +} +#endif + + /********************************************************************* * * Function : pcrs_compile_replacement @@ -193,7 +223,11 @@ int pcrs_compile_perl_options(char *optstring, int *flags) * Parameters : * 1 : replacement = replacement part of s/// operator * in perl syntax - * 2 : errptr = pointer to an integer in which error + * 2 : trivialflag = Flag that causes backreferences to be + * ignored. + * 3 : capturecount = Number of capturing subpatterns in + * the pattern. Needed for $+ handling. + * 4 : errptr = pointer to an integer in which error * conditions can be returned. * * Returns : pcrs_substitute data structure, or NULL if an @@ -201,89 +235,212 @@ int pcrs_compile_perl_options(char *optstring, int *flags) * the reason. * *********************************************************************/ -pcrs_substitute *pcrs_compile_replacement(char *replacement, int trivialflag, int *errptr) +static pcrs_substitute *pcrs_compile_replacement(const char *replacement, int trivialflag, int capturecount, int *errptr) { - int length, i, k = 0, l = 0, quoted = 0, idx; - char *text, *num_ptr, *numbers = "0123456789"; + int i, k, l, quoted; + char *text; pcrs_substitute *r; +#ifndef FUZZ + size_t length; +#else + static size_t length; +#endif + i = k = l = quoted = 0; - r = (pcrs_substitute *)malloc(sizeof(pcrs_substitute)); - if (r == NULL) return NULL; - memset(r, '\0', sizeof(pcrs_substitute)); + /* + * Sanity check + */ + if (NULL == replacement) + { + replacement = ""; + } - text = strdup(replacement); /* must be free()d by caller */ - if (text == NULL) + /* + * Get memory or fail + */ + if (NULL == (r = (pcrs_substitute *)malloc(sizeof(pcrs_substitute)))) { *errptr = PCRS_ERR_NOMEM; - free(r); return NULL; } + memset(r, '\0', sizeof(pcrs_substitute)); length = strlen(replacement); + if (NULL == (text = (char *)malloc(length + 1))) + { + free(r); + *errptr = PCRS_ERR_NOMEM; + return NULL; + } + memset(text, '\0', length + 1); + + + /* + * In trivial mode, just copy the substitute text + */ if (trivialflag) { - k = length; + strlcpy(text, replacement, length + 1); + k = (int)length; } + + /* + * Else, parse, cut out and record all backreferences + */ else - { - for (i=0; i < length; i++) + { + while (i < (int)length) { - /* Backslash treatment */ + /* Quoting */ if (replacement[i] == '\\') { if (quoted) { - text[k++] = replacement[i]; + text[k++] = replacement[i++]; quoted = 0; } else { - quoted = 1; + if (replacement[i+1] && strchr("tnrfae0", replacement[i+1])) + { + switch (replacement[++i]) + { + case 't': + text[k++] = '\t'; + break; + case 'n': + text[k++] = '\n'; + break; + case 'r': + text[k++] = '\r'; + break; + case 'f': + text[k++] = '\f'; + break; + case 'a': + text[k++] = 7; + break; + case 'e': + text[k++] = 27; + break; + case '0': + text[k++] = '\0'; + break; + } + i++; + } + else if (is_hex_sequence(&replacement[i])) + { + /* + * Replace a hex sequence with a single + * character with the sequence's ascii value. + * e.g.: '\x7e' => '~' + */ + const int ascii_value = xtoi(&replacement[i+2]); + + assert(ascii_value >= 0); + assert(ascii_value < 256); + text[k++] = (char)ascii_value; + i += 4; + } + else + { + quoted = 1; + i++; + } } continue; } - /* Dollar treatment */ - if (replacement[i] == '$' && !quoted && i < length - 1) + /* Backreferences */ + if (replacement[i] == '$' && !quoted && i < (int)(length - 1)) { - if (strchr("0123456789&", replacement[i + 1]) == NULL) + char *symbol, symbols[] = "'`+&"; + if (l >= PCRS_MAX_SUBMATCHES) { - text[k++] = replacement[i]; + freez(text); + freez(r); + *errptr = PCRS_WARN_BADREF; + return NULL; } - else + r->block_length[l] = (size_t)(k - r->block_offset[l]); + + /* Numerical backreferences */ + if (isdigit((int)replacement[i + 1])) { - r->block_length[l] = k - r->block_offset[l]; - r->backref[l] = 0; - if (replacement[i + 1] != '&') + while (i < (int)length && isdigit((int)replacement[++i])) { - while ((num_ptr = strchr(numbers, replacement[++i])) != NULL && i < length) - { - idx = num_ptr - numbers; - r->backref[l] = r->backref[l] * 10 + idx; - } - i--; + r->backref[l] = r->backref[l] * 10 + replacement[i] - 48; + } + if (r->backref[l] > capturecount) + { + freez(text); + freez(r); + *errptr = PCRS_WARN_BADREF; + return NULL; } - else - i++; - if (r->backref[l] < PCRS_MAX_SUBMATCHES) - r->backref_count[r->backref[l]] += 1; - l++; - r->block_offset[l] = k; + } + + /* Symbolic backreferences: */ + else if (NULL != (symbol = strchr(symbols, replacement[i + 1]))) + { + + if (symbol - symbols == 2) /* $+ */ + { + r->backref[l] = capturecount; + } + else if (symbol - symbols == 3) /* $& */ + { + r->backref[l] = 0; + } + else /* $' or $` */ + { + r->backref[l] = (int)(PCRS_MAX_SUBMATCHES + 1 - (symbol - symbols)); + } + i += 2; + } + + /* Invalid backref -> plain '$' */ + else + { + goto plainchar; + } + + assert(r->backref[l] < PCRS_MAX_SUBMATCHES + 2); + /* Valid and in range? -> record */ + if ((0 <= r->backref[l]) && + (r->backref[l] < PCRS_MAX_SUBMATCHES + 2) && + (l < PCRS_MAX_SUBMATCHES - 1)) + { + r->backref_count[r->backref[l]] += 1; + r->block_offset[++l] = k; + } + else + { + freez(text); + freez(r); + *errptr = PCRS_WARN_BADREF; + return NULL; } continue; } - /* Plain char treatment */ - text[k++] = replacement[i]; +plainchar: + /* Plain chars are copied */ + text[k++] = replacement[i++]; quoted = 0; } - } /* -END- if (!trivialflag) */ + } /* -END- if (!trivialflag) */ - text[k] = '\0'; + /* + * Finish & return + */ r->text = text; r->backrefs = l; - r->block_length[l] = k - r->block_offset[l]; + r->length = (size_t)k; + r->block_length[l] = (size_t)(k - r->block_offset[l]); + return r; } @@ -294,14 +451,13 @@ pcrs_substitute *pcrs_compile_replacement(char *replacement, int trivialflag, in * Function : pcrs_free_job * * Description : Frees the memory used by a pcrs_job struct and its - * dependant structures. Returns a pointer to the next - * job, if there was any, or NULL otherwise. + * dependent structures. * * Parameters : * 1 : job = pointer to the pcrs_job structure to be freed * * Returns : a pointer to the next job, if there was any, or - * NULL otherwise. + * NULL otherwise. * *********************************************************************/ pcrs_job *pcrs_free_job(pcrs_job *job) @@ -316,7 +472,14 @@ pcrs_job *pcrs_free_job(pcrs_job *job) { next = job->next; if (job->pattern != NULL) free(job->pattern); - if (job->hints != NULL) free(job->hints); + if (job->hints != NULL) + { +#ifdef PCRE_CONFIG_JIT + pcre_free_study(job->hints); +#else + free(job->hints); +#endif + } if (job->substitute != NULL) { if (job->substitute->text != NULL) free(job->substitute->text); @@ -328,6 +491,7 @@ pcrs_job *pcrs_free_job(pcrs_job *job) } + /********************************************************************* * * Function : pcrs_free_joblist @@ -344,7 +508,7 @@ pcrs_job *pcrs_free_job(pcrs_job *job) *********************************************************************/ void pcrs_free_joblist(pcrs_job *joblist) { - while ( NULL != (joblist = pcrs_free_job(joblist)) ) {}; + while (NULL != (joblist = pcrs_free_job(joblist))) {}; return; @@ -353,11 +517,12 @@ void pcrs_free_joblist(pcrs_job *joblist) /********************************************************************* * - * Function : pcrs_compile + * Function : pcrs_compile_command * - * Description : Main entry point. Takes a string with a Perl-style - * s/// command and returns a corresponding pcrs_job, - * or NULL if compiling the job fails at any stage. + * Description : Parses a string with a Perl-style s/// command, + * calls pcrs_compile, and returns a corresponding + * pcrs_job, or NULL if parsing or compiling the job + * fails. * * Parameters : * 1 : command = string with perl-style s/// command @@ -369,67 +534,70 @@ void pcrs_free_joblist(pcrs_job *joblist) * has the reason. * *********************************************************************/ -pcrs_job *pcrs_compile(char *command, int *errptr) +pcrs_job *pcrs_compile_command(const char *command, int *errptr) { - int i, k, l, limit, quoted = FALSE; + int i, k, l, quoted = FALSE; + size_t limit; char delimiter; - char *tokens[4]; + char *tokens[4]; pcrs_job *newjob; - i = k = l = 0; + k = l = 0; /* * Tokenize the perl command */ limit = strlen(command); if (limit < 4) - { + { *errptr = PCRS_ERR_CMDSYNTAX; return NULL; } else - { - delimiter = command[1]; - } + { + delimiter = command[1]; + } tokens[l] = (char *) malloc(limit + 1); - for (i=0; i <= limit; i++) + for (i = 0; i <= (int)limit; i++) { if (command[i] == delimiter && !quoted) { - if (l == 3) - { - l = -1; + if (l == 3) + { + l = -1; break; } - tokens[0][k++] = '\0'; + tokens[0][k++] = '\0'; tokens[++l] = tokens[0] + k; - continue; + continue; } - else if (command[i] == '\\' && !quoted && i+1 < limit && command[i+1] == delimiter) + else if (command[i] == '\\' && !quoted) { quoted = TRUE; - continue; + if (command[i+1] == delimiter) continue; + } + else + { + quoted = FALSE; } tokens[0][k++] = command[i]; - quoted = FALSE; } - /* * Syntax error ? */ if (l != 3) { - *errptr = PCRS_ERR_CMDSYNTAX; + *errptr = PCRS_ERR_CMDSYNTAX; free(tokens[0]); return NULL; } - newjob = pcrs_make_job(tokens[1], tokens[2], tokens[3], errptr); + newjob = pcrs_compile(tokens[1], tokens[2], tokens[3], errptr); free(tokens[0]); return newjob; @@ -438,7 +606,7 @@ pcrs_job *pcrs_compile(char *command, int *errptr) /********************************************************************* * - * Function : pcrs_make_job + * Function : pcrs_compile * * Description : Takes the three arguments to a perl s/// command * and compiles a pcrs_job structure from them. @@ -455,20 +623,24 @@ pcrs_job *pcrs_compile(char *command, int *errptr) * has the reason. * *********************************************************************/ -pcrs_job *pcrs_make_job(char *pattern, char *substitute, char *options, int *errptr) +pcrs_job *pcrs_compile(const char *pattern, const char *substitute, const char *options, int *errptr) { pcrs_job *newjob; int flags; + int capturecount; const char *error; + int pcre_study_options = 0; + + *errptr = 0; - /* + /* * Handle NULL arguments */ if (pattern == NULL) pattern = ""; if (substitute == NULL) substitute = ""; - if (options == NULL) options = ""; - /* + + /* * Get and init memory */ if (NULL == (newjob = (pcrs_job *)malloc(sizeof(pcrs_job)))) @@ -482,7 +654,7 @@ pcrs_job *pcrs_make_job(char *pattern, char *substitute, char *options, int *err /* * Evaluate the options */ - newjob->options = pcrs_compile_perl_options(options, &flags); + newjob->options = pcrs_parse_perl_options(options, &flags); newjob->flags = flags; @@ -497,107 +669,222 @@ pcrs_job *pcrs_make_job(char *pattern, char *substitute, char *options, int *err } +#ifdef PCRE_STUDY_JIT_COMPILE + if (!(flags & PCRS_DYNAMIC)) + { + pcre_study_options = PCRE_STUDY_JIT_COMPILE; + } +#endif + /* * Generate hints. This has little overhead, since the * hints will be NULL for a boring pattern anyway. */ - newjob->hints = pcre_study(newjob->pattern, 0, &error); + newjob->hints = pcre_study(newjob->pattern, pcre_study_options, &error); if (error != NULL) { *errptr = PCRS_ERR_STUDY; pcrs_free_job(newjob); return NULL; } - + + + /* + * Determine the number of capturing subpatterns. + * This is needed for handling $+ in the substitute. + */ + if (0 > (*errptr = pcre_fullinfo(newjob->pattern, newjob->hints, PCRE_INFO_CAPTURECOUNT, &capturecount))) + { + pcrs_free_job(newjob); + return NULL; + } + /* * Compile the substitute */ - if (NULL == (newjob->substitute = pcrs_compile_replacement(substitute, newjob->flags & PCRS_TRIVIAL, errptr))) + if (NULL == (newjob->substitute = pcrs_compile_replacement(substitute, newjob->flags & PCRS_TRIVIAL, capturecount, errptr))) { pcrs_free_job(newjob); return NULL; } - + return newjob; } +/********************************************************************* + * + * Function : pcrs_execute_list + * + * Description : This is a multiple job wrapper for pcrs_execute(). + * Apply the regular substitutions defined by the jobs in + * the joblist to the subject. + * The subject itself is left untouched, memory for the result + * is malloc()ed and it is the caller's responsibility to free + * the result when it's no longer needed. + * + * Note: For convenient string handling, a null byte is + * appended to the result. It does not count towards the + * result_length, though. + * + * + * Parameters : + * 1 : joblist = the chained list of pcrs_jobs to be executed + * 2 : subject = the subject string + * 3 : subject_length = the subject's length + * 4 : result = char** for returning the result + * 5 : result_length = size_t* for returning the result's length + * + * Returns : On success, the number of substitutions that were made. + * May be > 1 if job->flags contained PCRS_GLOBAL + * On failure, the (negative) pcre error code describing the + * failure, which may be translated to text using pcrs_strerror(). + * + *********************************************************************/ +int pcrs_execute_list(pcrs_job *joblist, char *subject, size_t subject_length, char **result, size_t *result_length) +{ + pcrs_job *job; + char *old, *new = NULL; + int hits, total_hits; + + old = subject; + *result_length = subject_length; + total_hits = 0; + + for (job = joblist; job != NULL; job = job->next) + { + hits = pcrs_execute(job, old, *result_length, &new, result_length); + + if (old != subject) free(old); + + if (hits < 0) + { + return(hits); + } + else + { + total_hits += hits; + old = new; + } + } + + *result = new; + return(total_hits); + +} + + /********************************************************************* * * Function : pcrs_execute * - * Description : Modify the subject by executing the regular substitution - * defined by the job. Since the result may be longer than - * the subject, its space requirements are precalculated in - * the matching phase and new memory is allocated accordingly. - * It is the caller's responsibility to free the result when - * it's no longer needed. + * Description : Apply the regular substitution defined by the job to the + * subject. + * The subject itself is left untouched, memory for the result + * is malloc()ed and it is the caller's responsibility to free + * the result when it's no longer needed. + * + * Note: For convenient string handling, a null byte is + * appended to the result. It does not count towards the + * result_length, though. * * Parameters : * 1 : job = the pcrs_job to be executed * 2 : subject = the subject (== original) string - * 3 : subject_length = the subject's length - * INCLUDING the terminating zero, if string! - * 4 : result = char** for returning the result - * 5 : result_length = int* for returning the result's length + * 3 : subject_length = the subject's length + * 4 : result = char** for returning the result (NULL on error) + * 5 : result_length = size_t* for returning the result's length * - * Returns : the number of substitutions that were made. May be > 1 - * if job->flags contained PCRS_GLOBAL + * Returns : On success, the number of substitutions that were made. + * May be > 1 if job->flags contained PCRS_GLOBAL + * On failure, the (negative) pcre error code describing the + * failure, which may be translated to text using pcrs_strerror(). * *********************************************************************/ -int pcrs_execute(pcrs_job *job, char *subject, int subject_length, char **result, int *result_length) +int pcrs_execute(pcrs_job *job, const char *subject, size_t subject_length, char **result, size_t *result_length) { int offsets[3 * PCRS_MAX_SUBMATCHES], - offset, i, k, + offset, + i, k, matches_found, - newsize, - submatches; - pcrs_match matches[PCRS_MAX_MATCHES]; + submatches, + max_matches = PCRS_MAX_MATCH_INIT; + size_t newsize; + pcrs_match *matches, *dummy; char *result_offset; - offset = i = k = 0; + offset = i = 0; + *result = NULL; - /* - * Sanity check + /* + * Sanity check & memory allocation */ - if (job == NULL || job->pattern == NULL || job->substitute == NULL) + if (job == NULL || job->pattern == NULL || job->substitute == NULL || NULL == subject) { - *result = NULL; return(PCRS_ERR_BADJOB); } - + if (NULL == (matches = (pcrs_match *)malloc((size_t)max_matches * sizeof(pcrs_match)))) + { + return(PCRS_ERR_NOMEM); + } + memset(matches, '\0', (size_t)max_matches * sizeof(pcrs_match)); + + /* * Find the pattern and calculate the space - * requirements for the result (newsize) + * requirements for the result */ - newsize=subject_length; + newsize = subject_length; - while ((submatches = pcre_exec(job->pattern, job->hints, subject, subject_length, offset, 0, offsets, 3 * PCRS_MAX_SUBMATCHES)) > 0) + while ((submatches = pcre_exec(job->pattern, job->hints, subject, (int)subject_length, offset, 0, offsets, 3 * PCRS_MAX_SUBMATCHES)) > 0) { - job->flags |= PCRS_SUCCESS; + job->flags |= PCRS_SUCCESS; matches[i].submatches = submatches; - for (k=0; k < submatches; k++) + + for (k = 0; k < submatches; k++) { matches[i].submatch_offset[k] = offsets[2 * k]; /* Note: Non-found optional submatches have length -1-(-1)==0 */ - matches[i].submatch_length[k] = offsets[2 * k + 1] - offsets[2 * k]; + matches[i].submatch_length[k] = (size_t)(offsets[2 * k + 1] - offsets[2 * k]); /* reserve mem for each submatch as often as it is ref'd */ - newsize += matches[i].submatch_length[k] * job->substitute->backref_count[k]; + newsize += matches[i].submatch_length[k] * (size_t)job->substitute->backref_count[k]; } /* plus replacement text size minus match text size */ - newsize += strlen(job->substitute->text) - matches[i].submatch_length[0]; + newsize += job->substitute->length - matches[i].submatch_length[0]; + + /* chunk before match */ + matches[i].submatch_offset[PCRS_MAX_SUBMATCHES] = 0; + matches[i].submatch_length[PCRS_MAX_SUBMATCHES] = (size_t)offsets[0]; + newsize += (size_t)offsets[0] * (size_t)job->substitute->backref_count[PCRS_MAX_SUBMATCHES]; + + /* chunk after match */ + matches[i].submatch_offset[PCRS_MAX_SUBMATCHES + 1] = offsets[1]; + matches[i].submatch_length[PCRS_MAX_SUBMATCHES + 1] = subject_length - (size_t)offsets[1] - 1; + newsize += (subject_length - (size_t)offsets[1]) * (size_t)job->substitute->backref_count[PCRS_MAX_SUBMATCHES + 1]; + + /* Storage for matches exhausted? -> Extend! */ + if (++i >= max_matches) + { + max_matches = (int)(max_matches * PCRS_MAX_MATCH_GROW); + if (NULL == (dummy = (pcrs_match *)realloc(matches, (size_t)max_matches * sizeof(pcrs_match)))) + { + free(matches); + return(PCRS_ERR_NOMEM); + } + matches = dummy; + } /* Non-global search or limit reached? */ - if (++i >= PCRS_MAX_MATCHES || !(job->flags & PCRS_GLOBAL) ) break; + if (!(job->flags & PCRS_GLOBAL)) break; /* Don't loop on empty matches */ if (offsets[1] == offset) - if (offset < subject_length) + if ((size_t)offset < subject_length) offset++; else break; @@ -605,47 +892,59 @@ int pcrs_execute(pcrs_job *job, char *subject, int subject_length, char **result else offset = offsets[1]; } - /* Pass pcre error through if failiure*/ - if (submatches < -1) return submatches; + /* Pass pcre error through if (bad) failure */ + if (submatches < PCRE_ERROR_NOMATCH) + { + free(matches); + return submatches; + } matches_found = i; - /* - * Get memory for the result + /* + * Get memory for the result (must be freed by caller!) + * and append terminating null byte. */ - if ((*result = (char *)malloc(newsize)) == NULL) /* must be free()d by caller */ + if ((*result = (char *)malloc(newsize + 1)) == NULL) { + free(matches); return PCRS_ERR_NOMEM; } + else + { + (*result)[newsize] = '\0'; + } - /* + /* * Replace */ offset = 0; result_offset = *result; - for (i=0; i < matches_found; i++) + for (i = 0; i < matches_found; i++) { /* copy the chunk preceding the match */ - memcpy(result_offset, subject + offset, matches[i].submatch_offset[0] - offset); + memcpy(result_offset, subject + offset, (size_t)(matches[i].submatch_offset[0] - offset)); result_offset += matches[i].submatch_offset[0] - offset; /* For every segment of the substitute.. */ - for (k=0; k <= job->substitute->backrefs; k++) + for (k = 0; k <= job->substitute->backrefs; k++) { /* ...copy its text.. */ memcpy(result_offset, job->substitute->text + job->substitute->block_offset[k], job->substitute->block_length[k]); result_offset += job->substitute->block_length[k]; - /* ..plus, if it's not the last chunk (i.e.: There IS a backref).. */ + /* ..plus, if it's not the last chunk, i.e.: There *is* a backref.. */ if (k != job->substitute->backrefs - /* ..and a nonempty match.. */ - && matches[i].submatch_length[job->substitute->backref[k]] > 0 - /* ..and in legal range, ... */ - && job->substitute->backref[k] <= PCRS_MAX_SUBMATCHES) + /* ..in legal range.. */ + && job->substitute->backref[k] < PCRS_MAX_SUBMATCHES + 2 + /* ..and referencing a real submatch.. */ + && job->substitute->backref[k] < matches[i].submatches + /* ..that is nonempty.. */ + && matches[i].submatch_length[job->substitute->backref[k]] > 0) { - /* copy the submatch that is ref'd. */ + /* ..copy the submatch that is ref'd. */ memcpy( result_offset, subject + matches[i].submatch_offset[job->substitute->backref[k]], @@ -654,18 +953,282 @@ int pcrs_execute(pcrs_job *job, char *subject, int subject_length, char **result result_offset += matches[i].submatch_length[job->substitute->backref[k]]; } } - offset = matches[i].submatch_offset[0] + matches[i].submatch_length[0]; + offset = matches[i].submatch_offset[0] + (int)matches[i].submatch_length[0]; } /* Copy the rest. */ - memcpy(result_offset, subject + offset, subject_length - offset); + memcpy(result_offset, subject + offset, subject_length - (size_t)offset); *result_length = newsize; + free(matches); return matches_found; } +#define is_hex_digit(x) ((x) && strchr("0123456789ABCDEF", toupper(x))) + +/********************************************************************* + * + * Function : is_hex_sequence + * + * Description : Checks the first four characters of a string + * and decides if they are a valid hex sequence + * (like '\x40'). + * + * Parameters : + * 1 : sequence = The string to check + * + * Returns : Non-zero if it's valid sequence, or + * Zero if it isn't. + * + *********************************************************************/ +static int is_hex_sequence(const char *sequence) +{ + return (sequence[0] == '\\' && + sequence[1] == 'x' && + is_hex_digit(sequence[2]) && + is_hex_digit(sequence[3])); +} + + +/* + * Functions below this line are only part of the pcrs version + * included in Privoxy. If you use any of them you should not + * try to dynamically link against external pcrs versions. + */ + +/********************************************************************* + * + * Function : pcrs_job_is_dynamic + * + * Description : Checks if a job has the "D" (dynamic) option set. + * + * Parameters : + * 1 : job = The job to check + * + * Returns : TRUE if the job is indeed dynamic, otherwise + * FALSE + * + *********************************************************************/ +int pcrs_job_is_dynamic(char *job) +{ + const char delimiter = job[1]; + const size_t length = strlen(job); + char *option; + + if (length < 5) + { + /* + * The shortest valid (but useless) + * dynamic pattern is "s@@@D" + */ + return FALSE; + } + + /* + * Everything between the last character + * and the last delimiter is an option ... + */ + for (option = job + length; *option != delimiter; option--) + { + if (*option == 'D') + { + /* + * ... and if said option is 'D' the job is dynamic. + */ + return TRUE; + } + } + return FALSE; + +} + + +/********************************************************************* + * + * Function : pcrs_get_delimiter + * + * Description : Tries to find a character that is safe to + * be used as a pcrs delimiter for a certain string. + * + * Parameters : + * 1 : string = The string to search in + * + * Returns : A safe delimiter if one was found, otherwise '\0'. + * + *********************************************************************/ +char pcrs_get_delimiter(const char *string) +{ + /* + * Some characters that are unlikely to + * be part of pcrs replacement strings. + */ + static const char delimiters[] = "><#+*~%^-:;!@"; + const char *d = delimiters; + + /* Take the first delimiter that isn't part of the string */ + while (*d && NULL != strchr(string, *d)) + { + d++; + } + return *d; + +} + + +/********************************************************************* + * + * Function : pcrs_execute_single_command + * + * Description : Apply single pcrs command to the subject. + * The subject itself is left untouched, memory for the result + * is malloc()ed and it is the caller's responsibility to free + * the result when it's no longer needed. + * + * Parameters : + * 1 : subject = the subject (== original) string + * 2 : pcrs_command = the pcrs command as string (s@foo@bar@) + * 3 : hits = int* for returning the number of modifications + * + * Returns : NULL in case of errors, otherwise the + * result of the pcrs command. + * + *********************************************************************/ +char *pcrs_execute_single_command(const char *subject, const char *pcrs_command, int *hits) +{ + size_t size; + char *result = NULL; + pcrs_job *job; + + assert(subject); + assert(pcrs_command); + + *hits = 0; + size = strlen(subject); + + job = pcrs_compile_command(pcrs_command, hits); + if (NULL != job) + { + *hits = pcrs_execute(job, subject, size, &result, &size); + if (*hits < 0) + { + freez(result); + } + pcrs_free_job(job); + } + return result; + +} + + +/********************************************************************* + * + * Function : pcrs_compile_dynamic_command + * + * Description : Takes a dynamic pcrs command, fills in the + * values of the variables and compiles it. + * + * Parameters : + * 1 : pcrs_command = The dynamic pcrs command to compile + * 2 : v = NULL terminated array of variables and their values. + * 3 : error = pcrs error code + * + * Returns : NULL in case of hard errors, otherwise the + * compiled pcrs job. + * + *********************************************************************/ +pcrs_job *pcrs_compile_dynamic_command(char *pcrs_command, const struct pcrs_variable v[], int *error) +{ + char buf[PCRS_BUFFER_SIZE]; + const char *original_pcrs_command = pcrs_command; + char *pcrs_command_tmp = NULL; + pcrs_job *job = NULL; + int truncation = 0; + char d; + int ret; + + while ((NULL != v->name) && (NULL != pcrs_command)) + { + assert(NULL != v->value); + + if (NULL == strstr(pcrs_command, v->name)) + { + /* + * Skip the substitution if the variable + * name isn't part of the pattern. + */ + v++; + continue; + } + + /* Use pcrs to replace the variable with its value. */ + d = pcrs_get_delimiter(v->value); + if ('\0' == d) + { + /* No proper delimiter found */ + *error = PCRS_ERR_CMDSYNTAX; + freez(pcrs_command_tmp); + return NULL; + } + + /* + * Variable names are supposed to contain alpha + * numerical characters plus '_' only. + */ + assert(NULL == strchr(v->name, d)); + + ret = snprintf(buf, sizeof(buf), "s%c\\$%s%c%s%cDgT", d, v->name, d, v->value, d); + assert(ret >= 0); + if (ret >= sizeof(buf)) + { + /* + * Value didn't completely fit into buffer, + * overwrite the end of the substitution text + * with a truncation message and close the pattern + * properly. + */ + static const char warning[] = "... [too long, truncated]"; + const size_t trailer_size = sizeof(warning) + 4; /* 4 for d + "DgT" */ + char *trailer_start = buf + sizeof(buf) - trailer_size; + + ret = snprintf(trailer_start, trailer_size, "%s%cDgT", warning, d); + assert(ret == trailer_size - 1); + assert(sizeof(buf) == strlen(buf) + 1); + truncation = 1; + } + + pcrs_command_tmp = pcrs_execute_single_command(pcrs_command, buf, error); + if (NULL == pcrs_command_tmp) + { + return NULL; + } + + if (pcrs_command != original_pcrs_command) + { + freez(pcrs_command); + } + pcrs_command = pcrs_command_tmp; + + v++; + } + + job = pcrs_compile_command(pcrs_command, error); + if (pcrs_command != original_pcrs_command) + { + freez(pcrs_command); + } + + if (truncation) + { + *error = PCRS_WARN_TRUNCATION; + } + + return job; + +} + + /* Local Variables: tab-width: 3