From eea35d0cab4c4751c5e24d54428f6c51bf072afb Mon Sep 17 00:00:00 2001
From: "Philip.Hazel" <Philip.Hazel@gmail.com>
Date: Wed, 19 Nov 2014 11:17:20 +0000
Subject: [PATCH] Fix zero-repeated assertion-as-condition bug.

---
 ChangeLog            |  3 +++
 src/pcre2_match.c    |  7 +++++--
 testdata/testinput2  |  6 ++++++
 testdata/testoutput2 | 10 ++++++++++
 4 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 8e67b5f..5f548bc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -53,4 +53,7 @@ matched against "abcd".
 
 8. The pcre2_substitute() function has been implemented.
 
+9. If an assertion condition was quantified with a minimum of zero (an odd
+thing to do, but it happened), SIGSEGV or other misbehaviour could occur.
+
 ****
diff --git a/src/pcre2_match.c b/src/pcre2_match.c
index 0699895..f03f3ed 100644
--- a/src/pcre2_match.c
+++ b/src/pcre2_match.c
@@ -1401,8 +1401,11 @@ for (;;)
         condition = TRUE;
 
         /* Advance ecode past the assertion to the start of the first branch,
-        but adjust it so that the general choosing code below works. */
-
+        but adjust it so that the general choosing code below works. If the 
+        assertion has a quantifier that allows zero repeats we must skip over 
+        the BRAZERO. This is a lunatic thing to do, but somebody did! */
+        
+        if (*ecode == OP_BRAZERO) ecode++; 
         ecode += GET(ecode, 1);
         while (*ecode == OP_ALT) ecode += GET(ecode, 1);
         ecode += 1 + LINK_SIZE - PRIV(OP_lengths)[condcode];
diff --git a/testdata/testinput2 b/testdata/testinput2
index 3c547d2..e318fac 100644
--- a/testdata/testinput2
+++ b/testdata/testinput2
@@ -4078,4 +4078,10 @@ a random value. /Ix
 
 # End of substitute tests 
 
+"((?=(?(?=(?(?=(?(?=())))*)))))"
+    a
+
+"(?(?=)?==)(((((((((?=)))))))))"
+    a
+
 # End of testinput2 
diff --git a/testdata/testoutput2 b/testdata/testoutput2
index 7b72388..861741a 100644
--- a/testdata/testoutput2
+++ b/testdata/testoutput2
@@ -13705,4 +13705,14 @@ Failed: error -34: bad option value
 
 # End of substitute tests 
 
+"((?=(?(?=(?(?=(?(?=())))*)))))"
+    a
+ 0: 
+ 1: 
+ 2: 
+
+"(?(?=)?==)(((((((((?=)))))))))"
+    a
+No match
+
 # End of testinput2