Mercurial > vim
view src/memfile_test.c @ 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 | f41b55f9357c |
children |
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/* vi:set ts=8 sts=4 sw=4 noet: * * VIM - Vi IMproved by Bram Moolenaar * * Do ":help uganda" in Vim to read copying and usage conditions. * Do ":help credits" in Vim to see a list of people who contributed. * See README.txt for an overview of the Vim source code. */ /* * memfile_test.c: Unittests for memfile.c * Mostly by Ivan Krasilnikov. */ #undef NDEBUG #include <assert.h> // Must include main.c because it contains much more than just main() #define NO_VIM_MAIN #include "main.c" // This file has to be included because the tested functions are static #include "memfile.c" #define index_to_key(i) ((i) ^ 15167) #define TEST_COUNT 50000 /* * Test mf_hash_*() functions. */ static void test_mf_hash(void) { mf_hashtab_T ht; mf_hashitem_T *item; blocknr_T key; long_u i; long_u num_buckets; mf_hash_init(&ht); // insert some items and check invariants for (i = 0; i < TEST_COUNT; i++) { assert(ht.mht_count == i); // check that number of buckets is a power of 2 num_buckets = ht.mht_mask + 1; assert(num_buckets > 0 && (num_buckets & (num_buckets - 1)) == 0); // check load factor assert(ht.mht_count <= (num_buckets << MHT_LOG_LOAD_FACTOR)); if (i < (MHT_INIT_SIZE << MHT_LOG_LOAD_FACTOR)) { // first expansion shouldn't have occurred yet assert(num_buckets == MHT_INIT_SIZE); assert(ht.mht_buckets == ht.mht_small_buckets); } else { assert(num_buckets > MHT_INIT_SIZE); assert(ht.mht_buckets != ht.mht_small_buckets); } key = index_to_key(i); assert(mf_hash_find(&ht, key) == NULL); // allocate and add new item item = LALLOC_CLEAR_ONE(mf_hashitem_T); assert(item != NULL); item->mhi_key = key; mf_hash_add_item(&ht, item); assert(mf_hash_find(&ht, key) == item); if (ht.mht_mask + 1 != num_buckets) { // hash table was expanded assert(ht.mht_mask + 1 == num_buckets * MHT_GROWTH_FACTOR); assert(i + 1 == (num_buckets << MHT_LOG_LOAD_FACTOR)); } } // check presence of inserted items for (i = 0; i < TEST_COUNT; i++) { key = index_to_key(i); item = mf_hash_find(&ht, key); assert(item != NULL); assert(item->mhi_key == key); } // delete some items for (i = 0; i < TEST_COUNT; i++) { if (i % 100 < 70) { key = index_to_key(i); item = mf_hash_find(&ht, key); assert(item != NULL); assert(item->mhi_key == key); mf_hash_rem_item(&ht, item); assert(mf_hash_find(&ht, key) == NULL); mf_hash_add_item(&ht, item); assert(mf_hash_find(&ht, key) == item); mf_hash_rem_item(&ht, item); assert(mf_hash_find(&ht, key) == NULL); vim_free(item); } } // check again for (i = 0; i < TEST_COUNT; i++) { key = index_to_key(i); item = mf_hash_find(&ht, key); if (i % 100 < 70) { assert(item == NULL); } else { assert(item != NULL); assert(item->mhi_key == key); } } // free hash table and all remaining items mf_hash_free_all(&ht); } int main(void) { test_mf_hash(); return 0; }