commit 989052047eea7f35da0d7ca268791b2442ee1553
author Victor Stinner <vstinner@redhat.com> Sat Dec 01 02:46:40 2018 +0100
committer GitHub <noreply@github.com> Sat Dec 01 02:46:40 2018 +0100
tree 6ec7ed8a81dfeac902e36e0677185a465df3107b
parent 503ce5c482cb267b0770bc46c315d5cf822bdca9

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.

Objects/structseq.c

diff --git a/Objects/structseq.c b/Objects/structseq.c
index 05ea87b..cf94155 100644
--- a/Objects/structseq.c
+++ b/Objects/structseq.c
@@ -182,9 +182,9 @@
     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++ = '(';