[Python-Dev] cpython: Use strncat() instead of strcat() to silence some warnings. (original) (raw)
Serhiy Storchaka storchaka at gmail.com
Sat Jul 20 14:48:09 CEST 2013
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20.07.13 15:36, Antoine Pitrou написав(ла):
On Sat, 20 Jul 2013 15:23:46 +0300 Serhiy Storchaka <storchaka at gmail.com> wrote:
20.07.13 15:12, christian.heimes написав(ла):
http://hg.python.org/cpython/rev/c92f4172d122 changeset: 84723:c92f4172d122 user: Christian Heimes <christian at cheimes.de> date: Sat Jul 20 14:11:28 2013 +0200 summary: Use strncat() instead of strcat() to silence some warnings. CID 486616, CID 486617, CID 486615
[...] This will wrong when strlen(fname) is 30. strncat() will copy only 30 bytes, without terminal NUL. So, for the record, this is roughly how Rasmus Lerdorf introduced a security hole in PHP 5.3.7: "For people asking me out-of-band what the screw-up was, it was pretty simple. I changed this code: memcpy(passwd, MD5MAGIC, MD5MAGICLEN); strlcpy(passwd + MD5MAGICLEN, sp, sl + 1); strcat(passwd, "$"); to: memcpy(passwd, MD5MAGIC, MD5MAGICLEN); strlcpy(passwd + MD5MAGICLEN, sp, sl + 1); strlcat(passwd, "$", 1); because the Coverity static analyzer warned about using strcat [emphasis mine] and we generally try to avoid naked strcat/strcpy in the codebase even though in this case it is safe to do." https://plus.google.com/113641248237520845183/posts/g68d9RvRA1i
strlcat != strncat. strlcat(dst, src, 1) actually do nothing.
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