From: Paul Eggert <eggert@cs.ucla.edu>
Date: Mon, 21 Jan 2019 19:08:13 +0000 (-0800)
Subject: regex: fix read overrun [BZ #24114]
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=2aee101ff6075dd97a99982a1ba29e21ec25c52f;p=thirdparty%2Fglibc.git

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.

(cherry picked from commit 583dd860d5b833037175247230a328f0050dbfe9)
---

diff --git a/ChangeLog b/ChangeLog
index e5011123eb7..0ef60fa5ac5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2019-01-31  Paul Eggert  <eggert@cs.ucla.edu>
+
+	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.
+
 2018-11-07  Andreas Schwab  <schwab@suse.de>
 
 	[BZ #23864]
diff --git a/posix/regexec.c b/posix/regexec.c
index 73644c23413..06b8487c3e3 100644
--- a/posix/regexec.c
+++ b/posix/regexec.c
@@ -1289,8 +1289,10 @@ 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;
 		}
 	    }