glibc: backport fix for regexec buffer read overrun

Problem found by AddressSanitizer[1]:

 Latest `grep` (git commit 1019e6e) compiled with asan may cause a
 heap-buffer-overflow when `-i` is specified.

     ./grep -i '\(\(\)*.\)*\(\)\(\)\1' /bin/chvt

 =================================================================
 ==16206==ERROR: AddressSanitizer: heap-buffer-overflow on address

1. https://debbugs.gnu.org/34140

Ref: https://sourceware.org/bugzilla/show_bug.cgi?id=24114
Signed-off-by: Alin Nastac <alin.nastac@gmail.com>
[commit title and description facelift]
Signed-off-by: Petr Štetiar <ynezz@true.cz>
master
Alin Nastac 5 years ago committed by Hans Dedecker
parent 929c6d733a
commit a50c2190d3
  1. 26
      toolchain/glibc/patches/001-regex-read-overrun.patch

@ -0,0 +1,26 @@
commit 583dd860d5b833037175247230a328f0050dbfe9
Author: Paul Eggert <eggert@cs.ucla.edu>
Date: Mon Jan 21 11:08:13 2019 -0800
regex: fix read overrun [BZ #24114]
Problem found by AddressSanitizer, reported by Hongxu Chen in:
https://debbugs.gnu.org/34140
* posix/regexec.c (proceed_next_node):
Do not read past end of input buffer.
--- a/posix/regexec.c
+++ b/posix/regexec.c
@@ -1293,8 +1293,10 @@ proceed_next_node (const re_match_context_t *mctx, Idx nregs, regmatch_t *regs,
else if (naccepted)
{
char *buf = (char *) re_string_get_buffer (&mctx->input);
- if (memcmp (buf + regs[subexp_idx].rm_so, buf + *pidx,
- naccepted) != 0)
+ if (mctx->input.valid_len - *pidx < naccepted
+ || (memcmp (buf + regs[subexp_idx].rm_so, buf + *pidx,
+ naccepted)
+ != 0))
return -1;
}
}
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