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authorPablo Neira <pablo@netfilter.org>2014-04-01 19:38:44 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-04-14 06:42:18 -0700
commitdbd3f730cf94e5ff51c196f6765a87e9e113ee64 (patch)
treef4cc3976570623ae3ed8b4336b0db87c70f13cf4 /lib
parent2e6f312e108b9f5609d601c4988c479e5cc9330d (diff)
downloadlinux-linaro-stable-dbd3f730cf94e5ff51c196f6765a87e9e113ee64.tar.gz
netlink: don't compare the nul-termination in nla_strcmp
[ Upstream commit 8b7b932434f5eee495b91a2804f5b64ebb2bc835 ] nla_strcmp compares the string length plus one, so it's implicitly including the nul-termination in the comparison. int nla_strcmp(const struct nlattr *nla, const char *str) { int len = strlen(str) + 1; ... d = memcmp(nla_data(nla), str, len); However, if NLA_STRING is used, userspace can send us a string without the nul-termination. This is a problem since the string comparison will not match as the last byte may be not the nul-termination. Fix this by skipping the comparison of the nul-termination if the attribute data is nul-terminated. Suggested by Thomas Graf. Cc: Florian Westphal <fw@strlen.de> Cc: Thomas Graf <tgraf@suug.ch> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'lib')
-rw-r--r--lib/nlattr.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/lib/nlattr.c b/lib/nlattr.c
index 18eca7809b08..fc6754720ced 100644
--- a/lib/nlattr.c
+++ b/lib/nlattr.c
@@ -303,9 +303,15 @@ int nla_memcmp(const struct nlattr *nla, const void *data,
*/
int nla_strcmp(const struct nlattr *nla, const char *str)
{
- int len = strlen(str) + 1;
- int d = nla_len(nla) - len;
+ int len = strlen(str);
+ char *buf = nla_data(nla);
+ int attrlen = nla_len(nla);
+ int d;
+ if (attrlen > 0 && buf[attrlen - 1] == '\0')
+ attrlen--;
+
+ d = attrlen - len;
if (d == 0)
d = memcmp(nla_data(nla), str, len);