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author | Pablo Neira <pablo@netfilter.org> | 2014-04-01 19:38:44 +0200 |
---|---|---|
committer | Stefan Bader <stefan.bader@canonical.com> | 2014-05-20 16:35:10 +0200 |
commit | c644851a67eca7fcd0413d093cce1b816b1e421a (patch) | |
tree | f3b01dd3342b48208467006641e4df1e3ea10278 | |
parent | a5401293b1e9722702f84a15392989b89abca4fd (diff) | |
download | linux-2.6.32.y-drm33.z-c644851a67eca7fcd0413d093cce1b816b1e421a.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: Willy Tarreau <w@1wt.eu>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
-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 109d4fed44b142..51b84de320d0f3 100644 --- a/lib/nlattr.c +++ b/lib/nlattr.c @@ -299,9 +299,15 @@ 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); |