From 4d980ef2cd6bf458706048a5627d02ea8ebf39b4 Mon Sep 17 00:00:00 2001
From: Hugo van der Sanden <hv@crypt.org>
Date: Mon, 25 Mar 2019 11:27:12 +0000
Subject: [PATCH] coredump in Perl_re_intuit_start
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Make sure we have a valid non-utf8 'other' check substring before we
try to use it.

Petr Písař: Ported to 5.28.1 from
fd8def15a58c97aa89cce8569befded97fd8c3b7.

Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 regexec.c            |  9 +++++++--
 t/re/pat_rt_report.t | 11 ++++++++++-
 2 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/regexec.c b/regexec.c
index 830a16a..357a109 100644
--- a/regexec.c
+++ b/regexec.c
@@ -1277,8 +1277,8 @@ Perl_re_intuit_start(pTHX_
 
     /* now look for the 'other' substring if defined */
 
-    if (utf8_target ? prog->substrs->data[other_ix].utf8_substr
-                    : prog->substrs->data[other_ix].substr)
+    if (prog->substrs->data[other_ix].utf8_substr
+        || prog->substrs->data[other_ix].substr)
     {
 	/* Take into account the "other" substring. */
         char *last, *last1;
@@ -1288,6 +1288,11 @@ Perl_re_intuit_start(pTHX_
 
       do_other_substr:
         other = &prog->substrs->data[other_ix];
+        if (!utf8_target && !other->substr) {
+            if (!to_byte_substr(prog)) {
+                NON_UTF8_TARGET_BUT_UTF8_REQUIRED(fail);
+            }
+        }
 
         /* if "other" is anchored:
          * we've previously found a floating substr starting at check_at.
diff --git a/t/re/pat_rt_report.t b/t/re/pat_rt_report.t
index dd740e7..4dc2dec 100644
--- a/t/re/pat_rt_report.t
+++ b/t/re/pat_rt_report.t
@@ -20,7 +20,7 @@ use warnings;
 use 5.010;
 use Config;
 
-plan tests => 2504;  # Update this when adding/deleting tests.
+plan tests => 2505;  # Update this when adding/deleting tests.
 
 run_tests() unless caller;
 
@@ -1141,6 +1141,15 @@ EOP
         ok($s=~/(foo){1,0}|(?1)/,
             "RT #130561 - allowing impossible quantifier should not break recursion");
     }
+	{
+		# RT #133892 Coredump in Perl_re_intuit_start
+		# Second match flips to checking floating substring before fixed
+		# substring, which triggers a pathway that failed to check there
+		# was a non-utf8 version of the string before trying to use it
+		# resulting in a SEGV.
+		my $result = grep /b\x{1c0}ss0/i, qw{ xxxx xxxx0 };
+		ok($result == 0);
+	}
 
 } # End of sub run_tests
 
-- 
2.20.1