Commit e1201bc7 authored by Pedro Tammela's avatar Pedro Tammela Committed by David S. Miller
Browse files

net/sched: act_pedit: check static offsets a priori 



Static key offsets should always be on 32 bit boundaries. Validate them on
create/update time for static offsets and move the datapath validation
for runtime offsets only.

iproute2 already errors out if a given offset and data size cannot be
packed to a 32 bit boundary. This change will make sure users which
create/update pedit instances directly via netlink also error out,
instead of finding out when packets are traversing.

Reviewed-by: default avatarJamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: default avatarSimon Horman <simon.horman@corigine.com>
Signed-off-by: default avatarPedro Tammela <pctammela@mojatatu.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 0c83c521

net/sched/act_pedit.c

+14 −6
Original line number Diff line number Diff line
@@ -251,8 +251,16 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla, 
	memcpy(nparms->tcfp_keys, parm->keys, ksize);



	for (i = 0; i < nparms->tcfp_nkeys; ++i) {

		u32 offmask = nparms->tcfp_keys[i].offmask;

		u32 cur = nparms->tcfp_keys[i].off;



		/* The AT option can be added to static offsets in the datapath */

		if (!offmask && cur % 4) {

			NL_SET_ERR_MSG_MOD(extack, "Offsets must be on 32bit boundaries");

			ret = -EINVAL;

			goto put_chain;

		}



		/* sanitize the shift value for any later use */

		nparms->tcfp_keys[i].shift = min_t(size_t,

						   BITS_PER_TYPE(int) - 1,
@@ -261,7 +269,7 @@ static int tcf_pedit_init(struct net *net, struct nlattr *nla, 
		/* The AT option can read a single byte, we can bound the actual

		 * value with uchar max.

		 */

		cur += (0xff & nparms->tcfp_keys[i].offmask) >> nparms->tcfp_keys[i].shift;

		cur += (0xff & offmask) >> nparms->tcfp_keys[i].shift;



		/* Each key touches 4 bytes starting from the computed offset */

		nparms->tcfp_off_max_hint =
@@ -411,13 +419,13 @@ TC_INDIRECT_SCOPE int tcf_pedit_act(struct sk_buff *skb, 
					       sizeof(_d), &_d);

			if (!d)

				goto bad;

			offset += (*d & tkey->offmask) >> tkey->shift;

		}



			offset += (*d & tkey->offmask) >> tkey->shift;

			if (offset % 4) {

				pr_info("tc action pedit offset must be on 32 bit boundaries\n");

				goto bad;

			}

		}



		if (!offset_valid(skb, hoffset + offset)) {

			pr_info("tc action pedit offset %d out of bounds\n",