From: Victor Stinner <vstinner@redhat.com>
Date: Sat, 1 Dec 2018 01:46:40 +0000 (+0100)
Subject: Fix compiler warning in structseq_repr() (GH-10841)
X-Git-Tag: v3.8.0a1~374
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=989052047eea7f35da0d7ca268791b2442ee1553;p=python

Fix compiler warning in structseq_repr() (GH-10841)

Replace strncpy() with memcpy() in structseq_repr() to fix the
following compiler warning:

Objects/structseq.c:187:5: warning: 'strncpy' specified bound depends on the length of the source argument [-Wstringop-overflow=]
     strncpy(pbuf, typ->tp_name, len);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Objects/structseq.c:185:11: note: length computed here
     len = strlen(typ->tp_name) > TYPE_MAXSIZE ? TYPE_MAXSIZE :

The function writes the terminating NUL byte later.
---

diff --git a/Objects/structseq.c b/Objects/structseq.c
index 05ea87b67a..cf94155f18 100644
--- a/Objects/structseq.c
+++ b/Objects/structseq.c
@@ -182,9 +182,9 @@ structseq_repr(PyStructSequence *obj)
     endofbuf= &buf[REPR_BUFFER_SIZE-5];
 
     /* "typename(", limited to  TYPE_MAXSIZE */
-    len = strlen(typ->tp_name) > TYPE_MAXSIZE ? TYPE_MAXSIZE :
-                            strlen(typ->tp_name);
-    strncpy(pbuf, typ->tp_name, len);
+    len = strlen(typ->tp_name);
+    len = Py_MIN(len, TYPE_MAXSIZE);
+    memcpy(pbuf, typ->tp_name, len);
     pbuf += len;
     *pbuf++ = '(';