Mercurial > vim
view runtime/doc/pi_logipat.txt @ 33811:06219b3bdaf3 v9.0.2121
patch 9.0.2121: [security]: use-after-free in ex_substitute
Commit: https://github.com/vim/vim/commit/26c11c56888d01e298cd8044caf860f3c26f57bb
Author: Christian Brabandt <cb@256bit.org>
Date: Wed Nov 22 21:26:41 2023 +0100
patch 9.0.2121: [security]: use-after-free in ex_substitute
Problem: [security]: use-after-free in ex_substitute
Solution: always allocate memory
closes: #13552
A recursive :substitute command could cause a heap-use-after free in Vim
(CVE-2023-48706).
The whole reproducible test is a bit tricky, I can only reproduce this
reliably when no previous substitution command has been used yet
(which is the reason, the test needs to run as first one in the
test_substitute.vim file) and as a combination of the `:~` command
together with a :s command that contains the special substitution atom `~\=`
which will make use of a sub-replace special atom and calls a vim script
function.
There was a comment in the existing :s code, that already makes the
`sub` variable allocate memory so that a recursive :s call won't be able
to cause any issues here, so this was known as a potential problem
already. But for the current test-case that one does not work, because
the substitution does not start with `\=` but with `~\=` (and since
there does not yet exist a previous substitution atom, Vim will simply
increment the `sub` pointer (which then was not allocated dynamically)
and later one happily use a sub-replace special expression (which could
then free the `sub` var).
The following commit fixes this, by making the sub var always using
allocated memory, which also means we need to free the pointer whenever
we leave the function. Since sub is now always an allocated variable,
we also do no longer need the sub_copy variable anymore, since this one
was used to indicated when sub pointed to allocated memory (and had
therefore to be freed on exit) and when not.
Github Security Advisory:
https://github.com/vim/vim/security/advisories/GHSA-c8qm-x72m-q53q
Signed-off-by: Christian Brabandt <cb@256bit.org>
author | Christian Brabandt <cb@256bit.org> |
---|---|
date | Wed, 22 Nov 2023 22:15:05 +0100 |
parents | 9b7f90e56753 |
children |
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*pi_logipat.txt* Logical Patterns May 01, 2019 Author: Charles E. Campbell <NcampObell@SdrPchip.AorgM-NOSPAM> Copyright: (c) 2004-2016 by Charles E. Campbell *logiPat-copyright* The VIM LICENSE applies to LogiPat.vim and LogiPat.txt (see |copyright|) except use "LogiPat" instead of "Vim" No warranty, express or implied. Use At-Your-Own-Risk. ============================================================================== 1. Contents *logiPat* *logiPat-contents* 1. Contents.................: |logiPat-contents| 2. LogiPat Manual...........: |logiPat-manual| 3. LogiPat Examples.........: |logiPat-examples| 4. Caveat...................: |logiPat-caveat| 5. LogiPat History..........: |logiPat-history| ============================================================================== 2. LogiPat Manual *logiPat-manual* *logiPat-man* *logiPat-arg* *logiPat-input* *logiPat-pattern* *logiPat-operators* Boolean logic patterns are composed of operators ! = not | = logical-or & = logical-and grouping ( ... ) patterns "pattern" *logiPat-cmd* :LogiPat {boolean-logic pattern} *:LogiPat* :LogiPat is a command which takes a boolean-logic argument (|logiPat-arg|). :LP {boolean-logic pattern} *:LP* :LP is a shorthand command version of :LogiPat (|logiPat-cmd|). :LPE {boolean-logic pattern} *:LPE* No search is done, but the conversion from the boolean logic pattern to the regular expression is performed and echoed onto the display. :LogiPatFlags {search flags} *LogiPat-flags* LogiPat uses the |search()| command. The flags passed to that call to search() may be specified by the :LogiPatFlags command. :LPF {search flags} *:LPF* :LPF is a shorthand version of :LogiPatFlags. :let pat=LogiPat({boolean-logic pattern}) *LogiPat()* If one calls LogiPat() directly, no search is done, but the transformation from the boolean logic pattern into a regular expression pattern is performed and returned. To get a " inside a pattern, as opposed to having it delimit the pattern, double it. ============================================================================== 3. LogiPat Examples *logiPat-examples* LogiPat takes Boolean logic arguments and produces a regular expression which implements the choices. A series of examples follows: > :LogiPat "abc" < will search for lines containing the string :abc: > :LogiPat "ab""cd" < will search for lines containing the string :ab"cd: > :LogiPat !"abc" < will search for lines which don't contain the string :abc: > :LogiPat "abc"|"def" < will search for lines which contain either the string :abc: or the string :def: > :LogiPat !("abc"|"def") < will search for lines which don't contain either of the strings :abc: or :def: > :LogiPat "abc"&"def" < will search for lines which contain both of the strings :abc: and :def: > :let pat= LogiPat('!"abc"') < will return the regular expression which will match all lines not containing :abc: . The double quotes are needed to pass normal patterns to LogiPat, and differentiate such patterns from boolean logic operators. ============================================================================== 4. Caveat *logiPat-caveat* The "not" operator may be fragile; ie. it may not always play well with the & (logical-and) and | (logical-or) operators. Please try out your patterns, possibly with :set hls, to insure that what is matching is what you want. ============================================================================== 5. LogiPat History *logiPat-history* v4 Jun 22, 2015 * LogiPat has been picked up by Bram M for standard plugin distribution; hence the name change v3 Sep 25, 2006 * LP_Or() fixed; it now encapsulates its output in \%(...\) parentheses Dec 12, 2011 * |:LPE| added * "" is mapped to a single " and left inside patterns v2 May 31, 2005 * LPF and LogiPatFlags commands weren't working v1 May 23, 2005 * initial release ============================================================================== vim:tw=78:ts=8:noet:ft=help