diff options
| author | Pablo Neira <pablo@netfilter.org> | 2014-04-01 19:38:44 +0200 |
|---|---|---|
| committer | Show Liu <show.liu@linaro.org> | 2014-06-18 11:39:54 +0800 |
| commit | 9442453b67584252a74a022bca4b74b92c3f0b72 (patch) | |
| tree | 9fe12ff5648996c52d834cb9d7b5d8e15c76cf36 /lib | |
| parent | dde2713234ea94c0fd0072f3b478021df984b559 (diff) | |
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.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/lib/nlattr.c b/lib/nlattr.c index 18eca7809b0..fc6754720ce 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); |