Mercurial > vim
view src/osdef.sh @ 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 | befdf44737d1 |
children |
line wrap: on
line source
#! /bin/sh # # osdef.sh -- copy osdef.h.in to osdef.h while removing declarations # found in the system header files. Caution: weird sed magic going on here. # Warnings are printed if sed did not survive. # # (C) Michael Schroeder, Juergen Weigert # # osdef.h.in has been split into osdef1.h.in and osdef2.h.in, because some # sed's could not handle the amount of commands (is 50 commands the limit?). # # 31.10.95 jw. if test -z "$CC"; then CC=cc fi if test -z "$srcdir"; then srcdir=. fi # Make sure collation works as expected # swedish range [a-z] does not match 'w' export LC_COLLATE=C export LC_ALL= rm -f core* *.core cat << EOF > osdef0.c #ifndef __APPLE__ # define select select_declared_wrong #endif #define tgetstr tgetstr_declared_wrong #include "auto/config.h" #include "os_unix.h" /* bring in most header files, more follow below */ #include "os_unixx.h" /* bring in header files for os_unix.c */ #ifdef HAVE_TERMCAP_H # include <termcap.h> /* only for term.c */ #endif #ifdef HAVE_FCNTL_H # include <fcntl.h> /* only used in a few files */ #endif #ifdef HAVE_SYS_STATFS_H # include <sys/types.h> # include <sys/statfs.h> /* only for memfile.c */ #endif #ifdef HAVE_X11 # include <X11/Intrinsic.h> #endif EOF $CC -I. -I$srcdir -E osdef0.c >osdef0.cc # insert a space in front of each line, so that a function name at the # start of the line is matched with "[)*, ]\1[ (]" sed < osdef0.cc -e '/\(..*\)/s// \1/' > osdef0.ccc sed < $srcdir/osdef1.h.in -n -e '/^extern/s@.*[)* ][)* ]*\([a-zA-Z_][a-zA-Z0-9_]*\)(.*@/[)*, ][(]*\1[)]*[ (]/i\\\ \\/\\[^a-zA-Z_\\]\1(\\/d@p' > osdef11.sed sed < $srcdir/osdef2.h.in -n -e '/^extern/s@.*[)* ][)* ]*\([a-zA-Z_][a-zA-Z0-9_]*\)(.*@/[)*, ][(]*\1[)]*[ (]/i\\\ \\/\\[^a-zA-Z_\\]\1(\\/d@p' > osdef21.sed cat << EOF > osdef2.sed 1i\\ /* 1i\\ * osdef.h is automagically created from osdef?.h.in by osdef.sh -- DO NOT EDIT 1i\\ */ EOF cat osdef0.ccc | sed -n -f osdef11.sed >> osdef2.sed sed -f osdef2.sed < $srcdir/osdef1.h.in > auto/osdef.h cat osdef0.ccc | sed -n -f osdef21.sed > osdef2.sed sed -f osdef2.sed < $srcdir/osdef2.h.in >> auto/osdef.h rm osdef0.c osdef0.cc osdef0.ccc osdef11.sed osdef21.sed osdef2.sed if test -f core*; then file core* echo " Sorry, your sed is broken. Call the system administrator." echo " Meanwhile, you may try to compile Vim with an empty osdef.h file." echo " If you compiler complains about missing prototypes, move the needed" echo " ones from osdef1.h.in and osdef2.h.in to osdef.h." exit 1 fi cat $srcdir/osdef1.h.in $srcdir/osdef2.h.in >osdefX.h.in if eval test "`diff auto/osdef.h osdefX.h.in | wc -l`" -eq 4; then echo " Hmm, sed is very pessimistic about your system header files." echo " But it did not dump core -- strange! Let's continue carefully..." echo " If this fails, you may want to remove offending lines from osdef.h" echo " or try with an empty osdef.h file, if your compiler can do without" echo " function declarations." fi rm osdefX.h.in