Commit 8cca3397 authored by David S. Miller's avatar David S. Miller
Browse files

Merge branch 'netlink-strict-attribute-checking-follow-up' 



Michal Kubecek says:

====================
netlink: strict attribute checking follow-up

Three follow-up patches for recent strict netlink validation series.

Patch 1 fixes dump handling for genetlink families which validate and parse
messages themselves (e.g. because they need different policies for diferent
commands).

Patch 2 sets bad_attr in extack in one place where this was omitted.

Patch 3 adds new NL_VALIDATE_NESTED flags for strict validation to enable
checking that NLA_F_NESTED value in received messages matches expectations
and includes this flag in NL_VALIDATE_STRICT. This would change userspace
visible behavior but the previous switching to NL_VALIDATE_STRICT for new
code is still only in net-next at the moment.

v2: change error messages to mention NLA_F_NESTED explicitly
====================

Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parents 5eabc27d b424e432

include/net/netlink.h

+10 −1
Original line number Diff line number Diff line
@@ -401,6 +401,8 @@ struct nl_info { 
 *	are enforced going forward.

 * @NL_VALIDATE_STRICT_ATTRS: strict attribute policy parsing (e.g.

 *	U8, U16, U32 must have exact size, etc.)

 * @NL_VALIDATE_NESTED: Check that NLA_F_NESTED is set for NLA_NESTED(_ARRAY)

 *	and unset for other policies.

 */

enum netlink_validation {

	NL_VALIDATE_LIBERAL = 0,
@@ -408,6 +410,7 @@ enum netlink_validation { 
	NL_VALIDATE_MAXTYPE = BIT(1),

	NL_VALIDATE_UNSPEC = BIT(2),

	NL_VALIDATE_STRICT_ATTRS = BIT(3),

	NL_VALIDATE_NESTED = BIT(4),

};



#define NL_VALIDATE_DEPRECATED_STRICT (NL_VALIDATE_TRAILING |\
@@ -415,7 +418,8 @@ enum netlink_validation { 
#define NL_VALIDATE_STRICT (NL_VALIDATE_TRAILING |\

			    NL_VALIDATE_MAXTYPE |\

			    NL_VALIDATE_UNSPEC |\

			    NL_VALIDATE_STRICT_ATTRS)

			    NL_VALIDATE_STRICT_ATTRS |\

			    NL_VALIDATE_NESTED)



int netlink_rcv_skb(struct sk_buff *skb,

		    int (*cb)(struct sk_buff *, struct nlmsghdr *,
@@ -1132,6 +1136,11 @@ static inline int nla_parse_nested(struct nlattr *tb[], int maxtype, 
				   const struct nla_policy *policy,

				   struct netlink_ext_ack *extack)

{

	if (!(nla->nla_type & NLA_F_NESTED)) {

		NL_SET_ERR_MSG_ATTR(extack, nla, "NLA_F_NESTED is missing");

		return -EINVAL;

	}



	return __nla_parse(tb, maxtype, nla_data(nla), nla_len(nla), policy,

			   NL_VALIDATE_STRICT, extack);

}

lib/nlattr.c

+17 −1
Original line number Diff line number Diff line
@@ -184,6 +184,21 @@ static int validate_nla(const struct nlattr *nla, int maxtype, 
		}

	}



	if (validate & NL_VALIDATE_NESTED) {

		if ((pt->type == NLA_NESTED || pt->type == NLA_NESTED_ARRAY) &&

		    !(nla->nla_type & NLA_F_NESTED)) {

			NL_SET_ERR_MSG_ATTR(extack, nla,

					    "NLA_F_NESTED is missing");

			return -EINVAL;

		}

		if (pt->type != NLA_NESTED && pt->type != NLA_NESTED_ARRAY &&

		    pt->type != NLA_UNSPEC && (nla->nla_type & NLA_F_NESTED)) {

			NL_SET_ERR_MSG_ATTR(extack, nla,

					    "NLA_F_NESTED not expected");

			return -EINVAL;

		}

	}



	switch (pt->type) {

	case NLA_EXACT_LEN:

		if (attrlen != pt->len)
@@ -356,7 +371,8 @@ static int __nla_validate_parse(const struct nlattr *head, int len, int maxtype, 


		if (type == 0 || type > maxtype) {

			if (validate & NL_VALIDATE_MAXTYPE) {

				NL_SET_ERR_MSG(extack, "Unknown attribute type");

				NL_SET_ERR_MSG_ATTR(extack, nla,

						    "Unknown attribute type");

				return -EINVAL;

			}

			continue;

net/netlink/genetlink.c

+14 −10
Original line number Diff line number Diff line
@@ -537,22 +537,26 @@ static int genl_family_rcv_msg(const struct genl_family *family, 
			return -EOPNOTSUPP;



		if (!(ops->validate & GENL_DONT_VALIDATE_DUMP)) {

			unsigned int validate = NL_VALIDATE_STRICT;

			int hdrlen = GENL_HDRLEN + family->hdrsize;



			if (ops->validate & GENL_DONT_VALIDATE_DUMP_STRICT)

				validate = NL_VALIDATE_LIBERAL;



			if (nlh->nlmsg_len < nlmsg_msg_size(hdrlen))

				return -EINVAL;



			if (family->maxattr) {

				unsigned int validate = NL_VALIDATE_STRICT;



				if (ops->validate &

				    GENL_DONT_VALIDATE_DUMP_STRICT)

					validate = NL_VALIDATE_LIBERAL;

				rc = __nla_validate(nlmsg_attrdata(nlh, hdrlen),

						    nlmsg_attrlen(nlh, hdrlen),

					    family->maxattr, family->policy,

						    family->maxattr,

						    family->policy,

						    validate, extack);

				if (rc)

					return rc;

			}

		}



		if (!family->parallel_ops) {

			struct netlink_dump_control c = {

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