From 6708c5595fc6babdae0132f8a23cbe3558a58703 Mon Sep 17 00:00:00 2001
From: Michiharu Ariza <ariza@adobe.com>
Date: Wed, 5 Dec 2018 12:51:18 -0800
Subject: [PATCH] fix oss-fuzz issue 11675 (ASSERT: count <= str.len)

Also added an additional error check to avail ()
---
 src/hb-cff-interp-common.hh                   |  18 ++++++++++++++++--
 ...inimized-hb-subset-fuzzer-5768186323009536 | Bin 0 -> 337 bytes
 2 files changed, 16 insertions(+), 2 deletions(-)
 create mode 100644 test/fuzzing/fonts/clusterfuzz-testcase-minimized-hb-subset-fuzzer-5768186323009536

diff --git a/src/hb-cff-interp-common.hh b/src/hb-cff-interp-common.hh
index f2ccc2bdd..9b595ff1a 100644
--- a/src/hb-cff-interp-common.hh
+++ b/src/hb-cff-interp-common.hh
@@ -391,8 +391,22 @@ struct SubByteStr
 
   inline operator ByteStr (void) const { return ByteStr (str, offset, str.len - offset); }
 
-  inline bool avail (unsigned int count=1) const { return str.check_limit (offset, count); }
-  inline void inc (unsigned int count=1) { offset += count; assert (count <= str.len); }
+  inline bool avail (unsigned int count=1) const
+  {
+    return (!in_error () && str.check_limit (offset, count));
+  }
+  inline void inc (unsigned int count=1)
+  {
+    if (likely (!in_error () && (offset <= str.len) && (offset + count <= str.len)))
+    {
+      offset += count;
+    }
+    else
+    {
+      offset = str.len;
+      set_error ();
+    }
+  }
 
   inline void set_error (void) { error = true; }
   inline bool in_error (void) const { return error; }
diff --git a/test/fuzzing/fonts/clusterfuzz-testcase-minimized-hb-subset-fuzzer-5768186323009536 b/test/fuzzing/fonts/clusterfuzz-testcase-minimized-hb-subset-fuzzer-5768186323009536
new file mode 100644
index 0000000000000000000000000000000000000000..858604d717650226cc56864063bb778518f6233b
GIT binary patch
literal 337
zcmeYd3Grv(Qvd^JH#acNz`)1|5kV#YqjC|v|4@Js!OFs^AFFCQ2{M8_3&gJO)UZ%i
F0RU6-GRgn|

literal 0
HcmV?d00001