Privoxy 3.0.4 User Manual
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Privoxy 3.0.29 User Manual
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3. What's New in this Release

Privoxy 3.0.27 stable scales better in multi-user environments and brings a + couple of tuning directives. Privoxy 3.0.28 stable fixes two regressions + introduced in 3.0.27.

Changes in Privoxy 3.0.28 stable:

+
Bug fixes for regressions in 3.0.27:
+
- +
  Fixed misplaced parentheses. Reported by David Binderman.
  +
- +
  Changed two regression tests to depend on config directive enable-remote-toggle instead of + FEATURE_TOGGLE.
  +
+

Changes in Privoxy 3.0.27 stable:

+
General improvements:
+
- +
  Add a receive-buffer-size directive which can be used to set the size of the previously statically + allocated buffer in handle_established_connection(). Increasing the buffer size increases Privoxy's memory + usage but can lower the number of context switches and thereby reduce the CPU usage and potentially + increase the throughput. This is mostly relevant for fast network connections and large downloads that + don't require filtering. Sponsored by: Robert Klemme
  +
- +
  Add a listen-backlog directive which specifies the backlog value passed to listen(). Sponsored by: + Robert Klemme
  +
- +
  Add an enable-accept-filter directive which allows to toggle accept filter support at run time when + compiled with FEATURE_ACCEPT_FILTER support. It makes testing more convenient and now that it's optional we + can emit an error message if enabling the accept filter fails. Sponsored by: Robert Klemme
  +
- +
  Add a delay-response{} action. This is useful to tar pit JavaScript requests that are endlessly retried + in case of blocks. It can also be used to simulate a slow Internet connection. Sponsored by: Robert + Klemme
  +
- +
  Add a 'trusted-cgi-referrer' directive. It allows to configure another page or site that can be used to + reach sensitive CGI resources. Sponsored by: Robert Klemme
  +
- +
  Add a --fuzz mode which exposes Privoxy internals to input from files or stdout. Mainly tested with + American Fuzzy Lop. For details see: https://www.fabiankeil.de/talks/fuzzing-on-freebsd/ This work was + partially funded with donations and done as part of the Privoxy month in 2015.
  +
- +
  Consistently use the U(ngreedy) flag in the 'img-reorder' filter.
  +
- +
  listen_loop(): Reuse a single thread attribute object The object doesn't change and creating a new one + for every thread is a waste of (CPU) time. Sponsored by: Robert Klemme
  +
- +
  Free csp resources in the thread that belongs to the csp instead of the main thread which has enough on + its plate already. Sponsored by: Robert Klemme
  +
- +
  Improve 'socket timeout reached' message. Log the timeout that was triggered and downgrade the log level + to LOG_LEVEL_CONNECT to reduce the log noise with common debug settings. The timeout isn't necessary the + result of an error and usually merely indicates that Privoxy's socket timeout is lower than the relevant + timeouts used by client and server. Sponsored by: Robert Klemme
  +
- +
  Explicitly taint the server socket in case of CONNECT requests. This doesn't fix any known problems, but + makes some log messages less confusing.
  +
- +
  Let write_pid_file() terminate if the pid file can't be opened. Logging the issue at info level is + unlikely to help.
  +
- +
  log_error(): Reduce the mutex-protected area by not using a heap-allocated buffer that is shared between + all threads. This increases performance and reduces the latency with verbose debug settings and multiple + concurrent connections. Sponsored by: Robert Klemme
  +
- +
  Let zalloc() use calloc() if it's available. In some situations using calloc() can be faster than + malloc() + memset() and it should never be slower. In the real world the impact of this change is not + expected to be noticeable. Sponsored by: Robert Klemme
  +
- +
  Never use select() when poll() is available. On most platforms select() is limited by FD_SETSIZE while + poll() is not. This was a scaling issue for multi-user setups. Using poll() has no downside other than the + usual risk that code modifications may introduce new bugs that have yet to be found and fixed. At least in + theory this commit could also reduce the latency when there are lots of connections and select() would use + "bit fields in arrays of integers" to store file descriptors. Another side effect is that Privoxy no longer + has to stop monitoring the client sockets when pipelined requests are waiting but can't be read yet. This + code keeps the select()-based code behind ifdefs for now but hopefully it can be removed soonish to make + the code more readable. Sponsored by: Robert Klemme
  +
- +
  Add a 'reproducible-tarball-dist' target. It's currently separate from the "tarball-dist" target because + it requires a tar implementation with mtree spec support. It's far from being perfect and does not enforce + a reproducible mode, but it's better than nothing.
  +
- +
  Use arc4random() if it's available. While Privoxy doesn't need high quality pseudo-random numbers + there's no reason not to use them when we can and this silences a warning emitted by code checkers that + can't tell whether or not the quality matters.
  +
- +
  Show the FEATURE_EXTERNAL_FILTERS status on the status page. Better late than never. Previously a couple + of tests weren't executed as Privoxy-Regression-Test couldn't detect that the FEATURE_EXTERNAL_FILTERS + dependency was satisfied.
  +
- +
  Ditch FEATURE_IMAGE_DETECT_MSIE. It's an obsolete workaround we inherited from Junkbuster and was + already disabled by default. Users that feel the urge to work around issues with image requests coming from + an Internet Explorer version from more than 15 years ago can still do this using tags.
  +
- +
  Consistently use strdup_or_die() instead of strdup() in cases where allocation failures aren't expected. + Using strdup_or_die() allows to remove a couple of explicit error checks which slightly reduces the size of + the binary.
  +
- +
  Insert a refresh tag into the /client-tags CGI page when serving it while a client-specific tag is + temporarily enabled. This makes it less likely that the user ends up looking at tag state that is out of + date.
  +
- +
  Use absolute URLs in the client-tag forms. It's more consistent with the rest of the CGI page URLs and + makes it more convenient to copy the forms to external pages.
  +
- +
  cgi_error_disabled(): Use status code 403 and an appropriate response line
  +
- +
  Use a dedicated CGI handler to deal with tag-toggle requests As a result the /client-tags page is now + safe to reach without trusted Referer header which makes bookmarking or linking to it more convenient. + Finally, refreshing the /client-tags page to show the current state can no longer unintentionally repeat + the previous toggle request.
  +
- +
  Don't add a "Connection" header for CONNECT requests. Explicitly sending "Connection: close" is not + necessary and apparently it causes problems with some forwarding proxies that will close the connection + prematurely. Reported by Marc Thomas.
  +
- +
  Fix compiler warnings.
  +
+
+
Bug fixes:
+
- +
  rfc2553_connect_to(): Properly detect and log when poll() reached the time out. Previously this was + logged as: Could not connect to [...]: No error: 0. which isn't very helpful. Sponsored by: Robert + Klemme
  +
- +
  add_tag_for_client(): Set time_to_live properly. Previously the time_to_live was always set for the + first tag. Attempts to temporarily enable a tag would result in enabling it permanently unless no tag was + enabled already.
  +
- +
  Revert r1.165 which didn't perform as advertised. While the idea was to use "https:// when creating + links for the user manual on the website", the actual effect was to use "https://" when Privoxy was + supposed to serve the user manual itself. Reported by Yossi Zahn on Privoxy-devel@.
  +
- +
  socks5_connect(): Fail in case of unsupported address types. Previously they would not be detected right + away and Privoxy would fail later on with an error message that didn't make it obvious that the problem was + socks-related. So far, no such problems have actually been reported.
  +
- +
  socks5_connect(): Properly deal with socks replies that contain IPv6 addresses. Previously parts of the + reply were left unread and later on treated as invalid HTTP response data. Fixes #904 reported by Danny + Goossen who also provided the initial version of this patch.
  +
+
+
Action file improvements:
+
- +
  Unblock 'msdn.microsoft.com/'. It (presumably) isn't used to serve the kind of ads Privoxy should block + by default but happens to serve lots of pages with URLs that are likely to result in false positives. + Reported by bugreporter1694 in AF#939.
  +
- +
  Disable gif deanimation for requests tagged with CSS-REQUEST. The action will ignore content that isn't + considered text anyway and explicitly disabling it makes this more obvious if "action" debugging (debug + 65536) is enabled while "gif deanimation" debugging (debug 256) isn't.
  +
- +
  Explicitly disable HTML filters for requests with CSS-REQUEST tag. The filters are unlikely to break CSS + files but executing them without (intentionally) getting any hits is a waste of cpu time and makes the log + more noisy when running with "debug 64".
  +
- +
  Unblock 'adventofcode.com/'. Reported by Clint Adams in Debian bug #848211. Fixes Roland's AF#937.
  +
- +
  Unblock 'adlibris.com'. Reported by Wyrex in #935
  +
- +
  Unblock .golang.org/
  +
- +
  Add fast-redirects exception for '.youtube.com/.*origin=http'
  +
+
+
Privoxy-Log-Parser:
+
- +
  Don't gather host and resource statistics if they aren't requested. While the performance impact seems + negligible this significantly reduces the memory usage if there are lots of requests.
  +
- +
  Bump version as the behaviour (slightly) changed.
  +
- +
  Count connection failures as well in statistics mode. Sponsored by: Robert Klemme
  +
- +
  Count connection timeouts as well in statistics mode. Sponsored by: Robert Klemme
  +
- +
  Fix an 'uninitialized value' warning when generating statistics for a log file without response headers. + While privoxy-log-parser was supposed to detect this already, the check was flawed and the message the user + didn't see was somewhat confusing anyway. Now the message is less confusing, more helpful and actually + printed. Reported by: Robert Klemme
  +
+
+
Documentation improvements:
+
- +
  Refer to the git sources instead of CVS.
  +
- +
  Use GNU/Linux when referring to the OS instead of the kernel.
  +
- +
  Add FAQ entry for what to do if editing the config file is access denied.
  +
- +
  Add brief HTTP/2 FAQ.
  +
- +
  Add a small fuzzing section to the developer documentation.
  +
- +
  Add a client-header-tagger{client-ip-address} example.
  +
- +
  Stop suggesting that Privoxy is an anonymizing proxy. The term could lead to Privoxy users + overestimating what it can do on its own (without Tor).
  +
- +
  Make it more obvious that SPI accepts Paypal, too. Currently most donations are made through the Paypal + account managed by Zwiebelfreunde e.V. and a more even distribution would be useful.
  +
- +
  Suggest to log applying actions as well when reproducing problems.
  +
- +
  Explicitly mention that Privoxy binaries are built by individuals on their own systems. Buyer + beware!
  +
- +
  Mention the release feed on the homepage.
  +
- +
  Remove a mysterious comment with a GNU FDL link as it isn't useful and could confuse license scanners. + In May 2002 it was briefly claimed that "this document" was covered by the GNU FDL. The commit message + (r1.5) doesn't explain the motivation or whether all copyright holders were actually asked and agreed to + the declared license change. It's thus hard to tell whether or not the license change was legit, but + luckily two days later the "doc license" was "put" "back to GPL" anyway (r1.6). At the same time the + offending comment with a link to the FDL (not the GPL) was added for no obvious reason. Now it's gone + again.
  +
+
+
Regression tests:
+
- +
  Bump for-privoxy-version to 3.0.27 as we now rely on untrusted CGI request being rejected with status + code 403 (instead of 200).
  +
- +
  Update test for /send-stylesheet and add another one
  +
+
+
Templates:
+
- +
  Consistently use https:// when linking to the Privoxy website.
  +
- +
  Remove SourceForge references in Copyright header.
  +
- +
  Remove a couple of SourceForge references in a comment. While at it, fix the grammar.
  +
- +
  Move the site-specific documentation block before the generic one. While most Privoxy installations + don't have a site-specific documentation block, in cases were it exists it's likely to be more relevant + than the generic one. Showing it first makes it less likely that users stop reading before they reach it, + especially on pages that don't fit on the screen.
  +
+
+
Build system improvements:
+
- +
  Prefer openjade to jade. On some systems Jade produces HTML with unescaped ampersands in URLs.
  +
- +
  Prefer OpenSP to SP to be consistent.
  +
- +
  Have Docbook generated HTML files be straight ASCII. Dealing with a mixture of ISO-8859 and UTF-8 files + is problematic.
  +
- +
  Echo the filename to stderr for 'make dok-tidy'. Make it a bit easier to find errors in docbook + generated HTML.
  +
- +
  Warn when still using select().
  +
- +
  Warn when compiling without calloc().
  +
- +
  Make it more obvious that the --with-fdsetsize configure switch is pointless if poll() is available.
  +
- +
  Remove support for AmigaOS.
  +
- +
  Update windows build system to use supported software. The cygwin gcc -mno-cygwin option is no longer + supported, so convert the windows build system to use the cygwin cross-compiler to build "native" code.
  +
- +
  Add --enable-static-linking option for configure does the same thing as LDFLAGS=-static; ./configure but + nicer than mixing evars and configure options.
  +
+

3.1. Note to Upgraders

A quick list of things to be aware of before upgrading from earlier versions of Privoxy:

+
The recommended way to upgrade Privoxy is to backup your old + configuration files, install the new ones, verify that Privoxy is working + correctly and finally merge back your changes using diff and maybe + patch.
+
There are a number of new features in each Privoxy release and most of + them have to be explicitly enabled in the configuration files. Old configuration files obviously don't do + that and due to syntax changes using old configuration files with a new Privoxy isn't always possible anyway.
+
+
Note that some installers remove earlier versions completely, including configuration files, therefore you + should really save any important configuration files!
+
+
On the other hand, other installers don't overwrite existing configuration files, thinking you will want + to do that yourself.
+
+
In the default configuration only fatal errors are logged now. You can change that in the debug section of the configuration file. You may also want to enable more verbose + logging until you verified that the new Privoxy version is working as + expected.
+
+
Three other config file settings are now off by default: enable-remote-toggle, enable-remote-http-toggle, and enable-edit-actions. If you use or want these, you will need to + explicitly enable them, and be aware of the security issues involved.
+

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