• Pablo Neira's avatar
    netlink: don't compare the nul-termination in nla_strcmp · 8b7b9324
    Pablo Neira authored
    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: 's avatarPablo Neira Ayuso <pablo@netfilter.org>
    Signed-off-by: 's avatarDavid S. Miller <davem@davemloft.net>
    8b7b9324
nlattr.c 12.5 KB