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Commit 6f455f5f authored by Johannes Berg's avatar Johannes Berg Committed by David S. Miller
Browse files

netlink: add NLA_MIN_LEN 



Rather than using NLA_UNSPEC for this type of thing, use NLA_MIN_LEN
so we can make NLA_UNSPEC be NLA_REJECT under certain conditions for
future attributes.

While at it, also use NLA_EXACT_LEN for the struct example.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent f6ad55a6

include/net/netlink.h

+5 −1
Original line number Diff line number Diff line
@@ -183,6 +183,7 @@ enum { 
	NLA_REJECT,

	NLA_EXACT_LEN,

	NLA_EXACT_LEN_WARN,

	NLA_MIN_LEN,

	__NLA_TYPE_MAX,

};
@@ -212,6 +213,7 @@ enum nla_policy_validation { 
 *    NLA_NUL_STRING       Maximum length of string (excluding NUL)

 *    NLA_FLAG             Unused

 *    NLA_BINARY           Maximum length of attribute payload

 *    NLA_MIN_LEN          Minimum length of attribute payload

 *    NLA_NESTED,

 *    NLA_NESTED_ARRAY     Length verification is done by checking len of

 *                         nested header (or empty); len field is used if
@@ -230,6 +232,7 @@ enum nla_policy_validation { 
 *                         it is rejected.

 *    NLA_EXACT_LEN_WARN   Attribute should have exactly this length, a warning

 *                         is logged if it is longer, shorter is rejected.

 *    NLA_MIN_LEN          Minimum length of attribute payload

 *    All other            Minimum length of attribute payload

 *

 * Meaning of `validation_data' field:
@@ -281,7 +284,7 @@ enum nla_policy_validation { 
 * static const struct nla_policy my_policy[ATTR_MAX+1] = {

 * 	[ATTR_FOO] = { .type = NLA_U16 },

 *	[ATTR_BAR] = { .type = NLA_STRING, .len = BARSIZ },

 *	[ATTR_BAZ] = { .len = sizeof(struct mystruct) },

 *	[ATTR_BAZ] = { .type = NLA_EXACT_LEN, .len = sizeof(struct mystruct) },

 *	[ATTR_GOO] = { .type = NLA_BITFIELD32, .validation_data = &myvalidflags },

 * };

 */
@@ -302,6 +305,7 @@ struct nla_policy { 
#define NLA_POLICY_EXACT_LEN(_len)	{ .type = NLA_EXACT_LEN, .len = _len }

#define NLA_POLICY_EXACT_LEN_WARN(_len)	{ .type = NLA_EXACT_LEN_WARN, \

					  .len = _len }

#define NLA_POLICY_MIN_LEN(_len)	{ .type = NLA_MIN_LEN, .len = _len }



#define NLA_POLICY_ETH_ADDR		NLA_POLICY_EXACT_LEN(ETH_ALEN)

#define NLA_POLICY_ETH_ADDR_COMPAT	NLA_POLICY_EXACT_LEN_WARN(ETH_ALEN)

lib/nlattr.c

+8 −1
Original line number Diff line number Diff line
@@ -278,10 +278,17 @@ static int validate_nla(const struct nlattr *nla, int maxtype, 
			}

		}

		break;



	case NLA_UNSPEC:

	case NLA_MIN_LEN:

		if (attrlen < pt->len)

			goto out_err;

		break;



	default:

		if (pt->len)

			minlen = pt->len;

		else if (pt->type != NLA_UNSPEC)

		else

			minlen = nla_attr_minlen[pt->type];



		if (attrlen < minlen)