From e02d7478ebfc399a9d10ba0df60eee217aa7ab8f Mon Sep 17 00:00:00 2001

From: Karl Williamson <khw@cpan.org>

Date: Fri, 2 Feb 2018 15:14:27 -0700

Subject: (perl #132227) restart a node if we change to uni rules within the

 node and encounter a sharp S

This could lead to a buffer overflow.

---

 regcomp.c | 12 ++++++++++++

 1 file changed, 12 insertions(+)

diff --git a/regcomp.c b/regcomp.c

index c6c7cb4925..d79bd191c9 100644

--- a/regcomp.c

+++ b/regcomp.c

@@ -13323,6 +13323,18 @@ S_regatom(pTHX_ RExC_state_t *pRExC_state, I32 *flagp, U32 depth)

                          * /u.  This includes the multi-char fold SHARP S to

                          * 'ss' */

                         if (UNLIKELY(ender == LATIN_SMALL_LETTER_SHARP_S)) {

+

+                            /* If the node started out having uni rules, we

+                             * wouldn't have gotten here.  So this means

+                             * something in the middle has changed it, but

+                             * didn't think it needed to reparse.  But this

+                             * sharp s now does indicate the need for

+                             * reparsing. */

+                            if (RExC_uni_semantics) {

+                                p = oldp;

+                                goto loopdone;

+                            }

+

                             RExC_seen_unfolded_sharp_s = 1;

                             maybe_exactfu = FALSE;

                         }

-- 

2.11.0