Commit 03aeee0d authored by Amir Vadai's avatar Amir Vadai Committed by Ben Hutchings

net/sched: pedit: make sure that offset is valid

[ Upstream commit 95c2027b ]

Add a validation function to make sure offset is valid:
1. Not below skb head (could happen when offset is negative).
2. Validate both 'offset' and 'at'.
Signed-off-by: default avatarAmir Vadai <amir@vadai.me>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarBen Hutchings <ben@decadent.org.uk>
parent 38ae3328
......@@ -120,6 +120,17 @@ static int tcf_pedit_cleanup(struct tc_action *a, int bind)
return 0;
}
static bool offset_valid(struct sk_buff *skb, int offset)
{
if (offset > 0 && offset > skb->len)
return false;
if (offset < 0 && -offset > skb_headroom(skb))
return false;
return true;
}
static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,
struct tcf_result *res)
{
......@@ -147,6 +158,11 @@ static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,
if (tkey->offmask) {
char *d, _d;
if (!offset_valid(skb, off + tkey->at)) {
pr_info("tc filter pedit 'at' offset %d out of bounds\n",
off + tkey->at);
goto bad;
}
d = skb_header_pointer(skb, off + tkey->at, 1,
&_d);
if (!d)
......@@ -159,10 +175,10 @@ static int tcf_pedit(struct sk_buff *skb, const struct tc_action *a,
" offset must be on 32 bit boundaries\n");
goto bad;
}
if (offset > 0 && offset > skb->len) {
pr_info("tc filter pedit"
" offset %d can't exceed pkt length %d\n",
offset, skb->len);
if (!offset_valid(skb, off + offset)) {
pr_info("tc filter pedit offset %d out of bounds\n",
offset);
goto bad;
}
......
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