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