netlink: don't compare the nul-termination in nla_strcmp

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 <[email protected]>
Cc: Thomas Graf <[email protected]>
Signed-off-by: Pablo Neira Ayuso <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

0 files changed, 0 insertions, 0 deletions