From 4c3e518bff94e5f206a63e3a1e5d7e570402786b Mon Sep 17 00:00:00 2001
From: ph10 <ph10@6239d852-aaf2-0410-a92c-79f79f948069>
Date: Sat, 3 Aug 2019 08:30:40 +0000
Subject: [PATCH] Fix incorrect computation of group length when one branch
 exceeded 65535.
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git-svn-id: svn://vcs.exim.org/pcre2/code/trunk@1155 6239d852-aaf2-0410-a92c-79f79f948069
Petr Písař: Ported to 10.33.

Signed-off-by: Petr Písař <ppisar@redhat.com>
---
 src/pcre2_study.c    | 18 ++++++++++++------
 testdata/testinput2  |  8 ++++++++
 testdata/testoutput2 | 27 +++++++++++++++++++++++++++
 3 files changed, 47 insertions(+), 6 deletions(-)

diff --git a/src/pcre2_study.c b/src/pcre2_study.c
index e883c2e..cb5e7f1 100644
--- a/src/pcre2_study.c
+++ b/src/pcre2_study.c
@@ -103,6 +103,7 @@ find_minlength(const pcre2_real_code *re, PCRE2_SPTR code,
   int *backref_cache)
 {
 int length = -1;
+int branchlength = 0;
 int prev_cap_recno = -1;
 int prev_cap_d = 0;
 int prev_recurse_recno = -1;
@@ -110,9 +111,9 @@ int prev_recurse_d = 0;
 uint32_t once_fudge = 0;
 BOOL had_recurse = FALSE;
 BOOL dupcapused = (re->flags & PCRE2_DUPCAPUSED) != 0;
-recurse_check this_recurse;
-int branchlength = 0;
+PCRE2_SPTR nextbranch = code + GET(code, 1);
 PCRE2_UCHAR *cc = (PCRE2_UCHAR *)code + 1 + LINK_SIZE;
+recurse_check this_recurse;
 
 /* If this is a "could be empty" group, its minimum length is 0. */
 
@@ -128,16 +129,20 @@ if ((*countptr)++ > 1000) return -1;
 
 /* Scan along the opcodes for this branch. If we get to the end of the branch,
 check the length against that of the other branches. If the accumulated length
-passes 16-bits, stop. */
+passes 16-bits, reset to that value and skip the rest of the branch. */
 
 for (;;)
   {
   int d, min, recno;
-  PCRE2_UCHAR *cs, *ce;
-  PCRE2_UCHAR op = *cc;
+  PCRE2_UCHAR op, *cs, *ce;
 
-  if (branchlength >= UINT16_MAX) return UINT16_MAX;
+  if (branchlength >= UINT16_MAX)
+    {
+    branchlength = UINT16_MAX;
+    cc = (PCRE2_UCHAR *)nextbranch;
+    }
 
+  op = *cc;
   switch (op)
     {
     case OP_COND:
@@ -227,6 +232,7 @@ for (;;)
     if (length < 0 || (!had_recurse && branchlength < length))
       length = branchlength;
     if (op != OP_ALT) return length;
+    nextbranch = cc + GET(cc, 1);
     cc += 1 + LINK_SIZE;
     branchlength = 0;
     had_recurse = FALSE;
diff --git a/testdata/testinput2 b/testdata/testinput2
index 1bfe591..384239a 100644
--- a/testdata/testinput2
+++ b/testdata/testinput2
@@ -5603,4 +5603,12 @@ a)"xI
 # Expect error (recursion => not fixed length)
 /(\2)((?=(?<=\1)))/
 
+/\A\s*(a|(?:[^`]{28500}){4})/I
+    a
+
+/\A\s*((?:[^`]{28500}){4})/I
+
+/\A\s*((?:[^`]{28500}){4}|a)/I
+    a
+
 # End of testinput2
diff --git a/testdata/testoutput2 b/testdata/testoutput2
index 758b4db..0983741 100644
--- a/testdata/testoutput2
+++ b/testdata/testoutput2
@@ -16956,6 +16956,33 @@ No match
 /(\2)((?=(?<=\1)))/
 Failed: error 125 at offset 8: lookbehind assertion is not fixed length
 
+/\A\s*(a|(?:[^`]{28500}){4})/I
+Capture group count = 1
+Max lookbehind = 1
+Compile options: <none>
+Overall options: anchored
+Subject length lower bound = 1
+    a
+ 0: a
+ 1: a
+
+/\A\s*((?:[^`]{28500}){4})/I
+Capture group count = 1
+Max lookbehind = 1
+Compile options: <none>
+Overall options: anchored
+Subject length lower bound = 65535
+
+/\A\s*((?:[^`]{28500}){4}|a)/I
+Capture group count = 1
+Max lookbehind = 1
+Compile options: <none>
+Overall options: anchored
+Subject length lower bound = 1
+    a
+ 0: a
+ 1: a
+
 # End of testinput2
 Error -70: PCRE2_ERROR_BADDATA (unknown error number)
 Error -62: bad serialized data
-- 
2.20.1