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Commit ac6d141d authored by Pablo Neira Ayuso's avatar Pablo Neira Ayuso Committed by David S. Miller
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[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: default avatarPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent c8e2078c

net/netfilter/nfnetlink.c

+2 −14
Original line number Diff line number Diff line
@@ -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