regex: fix heap-use-after-free error

[BZ #18040]
Problem reported by Saito Takaaki <tails.saito@gmail.com> in
https://debbugs.gnu.org/32592
Call stack get_subexp->get_subexp_sub->clean_state_log_if_needed may
call extend_buffers which reallocates the re_string_t internal buffer.
Local variable 'buf' was not updated in such case, resulting in
use-after-free.
* posix/regexec.c (get_subexp): Update 'buf' after call to
get_subexp_sub.
This commit is contained in:
Assaf Gordon 2018-09-05 23:25:07 -07:00 committed by Paul Eggert
parent 0c1719e65b
commit 077caf61d8
2 changed files with 14 additions and 0 deletions

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@ -1,3 +1,16 @@
2018-12-15 Assaf Gordon <assafgordon@gmail.com>
regex: fix heap-use-after-free error
[BZ #18040]
Problem reported by Saito Takaaki <tails.saito@gmail.com> in
https://debbugs.gnu.org/32592
Call stack get_subexp->get_subexp_sub->clean_state_log_if_needed may
call extend_buffers which reallocates the re_string_t internal buffer.
Local variable 'buf' was not updated in such case, resulting in
use-after-free.
* posix/regexec.c (get_subexp): Update 'buf' after call to
get_subexp_sub.
2018-12-15 Florian Weimer <fweimer@redhat.com>
* support/blob_repeat.c (check_mul_overflow_size_t): New function.

View File

@ -2783,6 +2783,7 @@ get_subexp (re_match_context_t *mctx, Idx bkref_node, Idx bkref_str_idx)
return REG_ESPACE;
err = get_subexp_sub (mctx, sub_top, sub_last, bkref_node,
bkref_str_idx);
buf = (const char *) re_string_get_buffer (&mctx->input);
if (err == REG_NOMATCH)
continue;
}