vim-patch:9.0.2141: [security]: buffer-overflow in suggest_trie_walk

Problem:  [security]: buffer-overflow in suggest_trie_walk
Solution: Check n before using it as index into byts array

Basically, n as an index into the byts array, can point to beyond the byts
array. So let's double check, that n is within the expected range after
incrementing it from sp->ts_curi and bail out if it would be invalid.

Reported by @henices, thanks!

0fb375aae6

Co-authored-by: Christian Brabandt <cb@256bit.org>
This commit is contained in:
zeertzjq 2023-12-02 10:07:13 +08:00
parent 7402655132
commit 01edcd6db8
3 changed files with 14 additions and 0 deletions

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@ -1941,6 +1941,12 @@ static void suggest_trie_walk(suginfo_T *su, langp_T *lp, char *fword, bool soun
// - Skip the byte if it's equal to the byte in the word,
// accepting that byte is always better.
n += sp->ts_curi++;
// break out, if we would be accessing byts buffer out of bounds
if (byts == slang->sl_fbyts && n >= slang->sl_fbyts_len) {
got_int = true;
break;
}
c = byts[n];
if (soundfold && sp->ts_twordlen == 0 && c == '*') {
// Inserting a vowel at the start of a word counts less,

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@ -135,6 +135,13 @@ func Test_crash1_2()
\ ' && echo "crash 2: [OK]" >> '.. result .. "\<cr>")
call TermWait(buf, 350)
let file = 'crash/poc_suggest_trie_walk'
let cmn_args = "%s -u NONE -i NONE -n -e -s -S %s -c ':qa!'"
let args = printf(cmn_args, vim, file)
call term_sendkeys(buf, args ..
\ ' && echo "crash 3: [OK]" >> '.. result .. "\<cr>")
call TermWait(buf, 150)
" clean up
exe buf .. "bw!"
@ -143,6 +150,7 @@ func Test_crash1_2()
let expected = [
\ 'crash 1: [OK]',
\ 'crash 2: [OK]',
\ 'crash 3: [OK]',
\ ]
call assert_equal(expected, getline(1, '$'))