Mercurial > vim
view src/testdir/test_shortpathname.vim @ 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 | ae10b91ac6b3 |
children |
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" Test for shortpathname ':8' extension. " Only for use on Win32 systems! set encoding=utf-8 scriptencoding utf-8 source check.vim CheckMSWindows func TestIt(file, bits, expected) let res = fnamemodify(a:file, a:bits) if a:expected != '' call assert_equal(substitute(a:expected, '/', '\\', 'g'), \ substitute(res, '/', '\\', 'g'), \ "'" . a:file . "'->(" . a:bits . ")->'" . res . "'") endif endfunc func Test_ColonEight() let save_dir = getcwd() " This could change for CygWin to //cygdrive/c . let dir1 = 'c:/x.x.y' let trycount = 5 while 1 if !filereadable(dir1) && !isdirectory(dir1) break endif if trycount == 1 call assert_report("Fatal: '" . dir1 . "' exists, cannot run this test") return endif " When tests run in parallel the directory may exist, wait a bit until it " is gone. sleep 5 let trycount -= 1 endwhile let file1 = dir1 . '/zz.y.txt' let nofile1 = dir1 . '/z.y.txt' let dir2 = dir1 . '/VimIsTheGreatestSinceSlicedBread' let file2 = dir2 . '/z.txt' let nofile2 = dir2 . '/zz.txt' call mkdir(dir1, 'D') let resdir1 = substitute(fnamemodify(dir1, ':p:8'), '/$', '', '') call assert_match('\V\^c:/XX\x\x\x\x~1.Y\$', resdir1) let resfile1 = resdir1 . '/ZZY~1.TXT' let resnofile1 = resdir1 . '/z.y.txt' let resdir2 = resdir1 . '/VIMIST~1' let resfile2 = resdir2 . '/z.txt' let resnofile2 = resdir2 . '/zz.txt' call mkdir(dir2, 'D') call writefile([], file1, 'D') call writefile([], file2, 'D') call TestIt(file1, ':p:8', resfile1) call TestIt(nofile1, ':p:8', resnofile1) call TestIt(file2, ':p:8', resfile2) call TestIt(nofile2, ':p:8', resnofile2) call TestIt(nofile2, ':p:8:h', fnamemodify(resnofile2, ':h')) call chdir(dir1) call TestIt(file1, ':.:8', strpart(resfile1, strlen(resdir1)+1)) call TestIt(nofile1, ':.:8', strpart(resnofile1, strlen(resdir1)+1)) call TestIt(file2, ':.:8', strpart(resfile2, strlen(resdir1)+1)) call TestIt(nofile2, ':.:8', strpart(resnofile2, strlen(resdir1)+1)) let $HOME=dir1 call TestIt(file1, ':~:8', '~' . strpart(resfile1, strlen(resdir1))) call TestIt(nofile1, ':~:8', '~' . strpart(resnofile1, strlen(resdir1))) call TestIt(file2, ':~:8', '~' . strpart(resfile2, strlen(resdir1))) call TestIt(nofile2, ':~:8', '~' . strpart(resnofile2, strlen(resdir1))) cd c:/ call chdir(save_dir) endfunc func Test_ColonEight_MultiByte() let dir = 'Xtest' let file = dir . '/日本語のファイル.txt' call mkdir(dir, 'D') call writefile([], file, 'D') let sfile = fnamemodify(file, ':8') call assert_notequal(file, sfile) call assert_match('\~', sfile) endfunc func Test_ColonEight_notexists() let non_exists='C:\windows\newfile.txt' call assert_equal(non_exists, fnamemodify(non_exists, ':p:8')) endfunc " vim: shiftwidth=2 sts=2 expandtab