File regex-read-overrun.patch of Package glibc.18276

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.

Index: glibc-2.26/posix/regexec.c
===================================================================
--- glibc-2.26.orig/posix/regexec.c
+++ glibc-2.26/posix/regexec.c
@@ -1304,8 +1304,10 @@ proceed_next_node (const re_match_contex
 	      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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