act_pedit: access skb->data safely (db2c2417) · Commits · 戴 / test

net/sched/act_pedit.c

+14 −10

Original line number	Diff line number	Diff line
		@@ -125,7 +125,7 @@ static int tcf_pedit(struct sk_buff skb, struct tc_action a,
		{
		struct tcf_pedit *p = a->priv;
		int i, munged = 0;
		u8 *pptr;
		unsigned int off;

		if (!(skb->tc_verd & TC_OK2MUNGE)) {
		/* should we set skb->cloned? */
		@@ -134,7 +134,7 @@ static int tcf_pedit(struct sk_buff skb, struct tc_action a,
		}
		}

		pptr = skb_network_header(skb);
		off = skb_network_offset(skb);

		spin_lock(&p->tcf_lock);

		@@ -144,17 +144,17 @@ static int tcf_pedit(struct sk_buff skb, struct tc_action a,
		struct tc_pedit_key *tkey = p->tcfp_keys;

		for (i = p->tcfp_nkeys; i > 0; i--, tkey++) {
		u32 *ptr;
		u32 *ptr, _data;
		int offset = tkey->off;

		if (tkey->offmask) {
		if (skb->len > tkey->at) {
		char *j = pptr + tkey->at;
		offset += ((*j & tkey->offmask) >>
		tkey->shift);
		} else {
		char *d, _d;

		d = skb_header_pointer(skb, off + tkey->at, 1,
		&_d);
		if (!d)
		goto bad;
		}
		offset += (*d & tkey->offmask) >> tkey->shift;
		}

		if (offset % 4) {
		@@ -169,9 +169,13 @@ static int tcf_pedit(struct sk_buff skb, struct tc_action a,
		goto bad;
		}

		ptr = (u32 *)(pptr+offset);
		ptr = skb_header_pointer(skb, off + offset, 4, &_data);
		if (!ptr)
		goto bad;
		/* just do it, baby */
		ptr = ((ptr & tkey->mask) ^ tkey->val);
		if (ptr == &_data)
		skb_store_bits(skb, off + offset, ptr, 4);
		munged++;
		}