[NETFILTER]: nfnetlink: parse attributes with nfattr_parse in nfnetlink_check_attribute

Use nfattr_parse to parse attributes, this patch also modifies the default
behaviour since unknown attributes will be ignored instead of returning
EINVAL. This ensure backward compatibility: new libraries with new
attributes and old kernels can work.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/netfilter/nfnetlink.c b/net/netfilter/nfnetlink.c
index 9ba6aa4..dec36ab 100644 (file)
--- a/net/netfilter/nfnetlink.c
+++ b/net/netfilter/nfnetlink.c
@@ -151,26 +151,14 @@ nfnetlink_check_attributes(struct nfnetlink_subsystem *subsys,
                           struct nlmsghdr *nlh, struct nfattr *cda[])
 {
        int min_len = NLMSG_SPACE(sizeof(struct nfgenmsg));
-       u_int16_t attr_count;
        u_int8_t cb_id = NFNL_MSG_TYPE(nlh->nlmsg_type);
-
-       attr_count = subsys->cb[cb_id].attr_count;
-       memset(cda, 0, sizeof(struct nfattr *) * attr_count);
+       u_int16_t attr_count = subsys->cb[cb_id].attr_count;
 
        /* check attribute lengths. */
        if (likely(nlh->nlmsg_len > min_len)) {
                struct nfattr *attr = NFM_NFA(NLMSG_DATA(nlh));
                int attrlen = nlh->nlmsg_len - NLMSG_ALIGN(min_len);
-
-               while (NFA_OK(attr, attrlen)) {
-                       unsigned flavor = NFA_TYPE(attr);
-                       if (flavor) {
-                               if (flavor > attr_count)
-                                       return -EINVAL;
-                               cda[flavor - 1] = attr;
-                       }
-                       attr = NFA_NEXT(attr, attrlen);
-               }
+               nfattr_parse(cda, attr_count, attr, attrlen);
        }
 
        /* implicit: if nlmsg_len == min_len, we return 0, and an empty