From: Rich Felker <dalias@aerifal.cx>
Date: Fri, 20 Mar 2015 22:25:01 +0000 (-0400)
Subject: suppress backref processing in ERE regcomp
X-Git-Tag: v1.1.8~5
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=7c8c86f6308c7e0816b9638465a5917b12159e8f;p=oweals%2Fmusl.git

suppress backref processing in ERE regcomp

one of the features of ERE is that it's actually a regular language
and does not admit expressions which cannot be matched in linear time.
introduction of \n backref support into regcomp's ERE parsing was
unintentional.
---

diff --git a/src/regex/regcomp.c b/src/regex/regcomp.c
index bce6bc15..4d80cb1c 100644
--- a/src/regex/regcomp.c
+++ b/src/regex/regcomp.c
@@ -839,7 +839,7 @@ static reg_errcode_t parse_atom(tre_parse_ctx_t *ctx, const char *s)
 			s--;
 			break;
 		default:
-			if (isdigit(*s)) {
+			if (!ere && isdigit(*s)) {
 				/* back reference */
 				int val = *s - '0';
 				node = tre_ast_new_literal(ctx->mem, BACKREF, val, ctx->position);