Mercurial > vim
comparison src/testdir/test_substitute.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 | 9503dc55b5ed |
children |
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33810:bb31f05f6b57 | 33811:06219b3bdaf3 |
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1 " Tests for the substitute (:s) command | 1 " Tests for the substitute (:s) command |
2 | 2 |
3 source shared.vim | 3 source shared.vim |
4 source check.vim | 4 source check.vim |
5 source screendump.vim | 5 source screendump.vim |
6 | |
7 " NOTE: This needs to be the first test to be | |
8 " run in the file, since it depends on | |
9 " that the previous substitution atom | |
10 " was not yet set. | |
11 " | |
12 " recursive call of :s and sub-replace special | |
13 " (did cause heap-use-after free in < v9.0.2121) | |
14 func Test_aaaa_substitute_expr_recursive_special() | |
15 func R() | |
16 " FIXME: leaving out the 'n' flag leaks memory, why? | |
17 %s/./\='.'/gn | |
18 endfunc | |
19 new Xfoobar_UAF | |
20 put ='abcdef' | |
21 let bufnr = bufnr('%') | |
22 try | |
23 silent! :s/./~\=R()/0 | |
24 "call assert_fails(':s/./~\=R()/0', 'E939:') | |
25 let @/='.' | |
26 ~g | |
27 catch /^Vim\%((\a\+)\)\=:E565:/ | |
28 endtry | |
29 delfunc R | |
30 exe bufnr .. "bw!" | |
31 endfunc | |
6 | 32 |
7 func Test_multiline_subst() | 33 func Test_multiline_subst() |
8 enew! | 34 enew! |
9 call append(0, ["1 aa", | 35 call append(0, ["1 aa", |
10 \ "bb", | 36 \ "bb", |
145 split Xsubfile | 171 split Xsubfile |
146 s/^/x | 172 s/^/x |
147 call feedkeys("Qsc\<CR>y", 'tx') | 173 call feedkeys("Qsc\<CR>y", 'tx') |
148 bwipe! | 174 bwipe! |
149 endfunc | 175 endfunc |
150 | |
151 " Test %s/\n// which is implemented as a special case to use a | 176 " Test %s/\n// which is implemented as a special case to use a |
152 " more efficient join rather than doing a regular substitution. | 177 " more efficient join rather than doing a regular substitution. |
153 func Test_substitute_join() | 178 func Test_substitute_join() |
154 new | 179 new |
155 | 180 |
1445 wincmd x | 1470 wincmd x |
1446 return 'XXXX' | 1471 return 'XXXX' |
1447 endfunc | 1472 endfunc |
1448 new Xfoobar | 1473 new Xfoobar |
1449 let bufnr = bufnr('%') | 1474 let bufnr = bufnr('%') |
1450 put ="abcdef" | 1475 put ='abcdef' |
1451 silent! s/\%')/\=R() | 1476 silent! s/\%')/\=R() |
1452 call assert_fails(':%s/./\=R()/g', 'E565:') | 1477 call assert_fails(':%s/./\=R()/g', 'E565:') |
1453 delfunc R | 1478 delfunc R |
1454 exe bufnr .. "bw!" | 1479 exe bufnr .. "bw!" |
1455 endfunc | 1480 endfunc |
1456 | 1481 |
1482 " recursive call of :s using test-replace special | |
1483 func Test_substitute_expr_recursive() | |
1484 func Q() | |
1485 %s/./\='foobar'/gn | |
1486 return "foobar" | |
1487 endfunc | |
1488 func R() | |
1489 %s/./\=Q()/g | |
1490 endfunc | |
1491 new Xfoobar_UAF | |
1492 let bufnr = bufnr('%') | |
1493 put ='abcdef' | |
1494 silent! s/./\=R()/g | |
1495 call assert_fails(':%s/./\=R()/g', 'E565:') | |
1496 delfunc R | |
1497 delfunc Q | |
1498 exe bufnr .. "bw!" | |
1499 endfunc | |
1500 | |
1457 " vim: shiftwidth=2 sts=2 expandtab | 1501 " vim: shiftwidth=2 sts=2 expandtab |