commit df6d7b406f3d1b2e4e2014751bfa25574c4df222
author Xiang Zhang <angwerzx@126.com> Mon Mar 06 18:17:10 2017 +0800
committer GitHub <noreply@github.com> Mon Mar 06 18:17:10 2017 +0800
tree 17be021c71e543c71a5e2e21e929d481c096fd2d
parent 4e1a065c20856a00d0fe88ce022b249170608058

[3.6] bpo-29714: Fix a regression that bytes format may fail when containing zero bytes inside. (GH-504)

Objects/bytesobject.c

diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index 5d48440..801711f 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -619,11 +619,11 @@
             Py_ssize_t len;
             char *pos;
 
-            pos = strchr(fmt + 1, '%');
+            pos = (char *)memchr(fmt + 1, '%', fmtcnt);
             if (pos != NULL)
                 len = pos - fmt;
             else
-                len = format_len - (fmt - format);
+                len = fmtcnt + 1;
             assert(len != 0);
 
             memcpy(res, fmt, len);