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bpf: Move skb->len == 0 checks into __bpf_redirect 

[ Upstream commit 114039b342 ]

To avoid potentially breaking existing users.

Both mac/no-mac cases have to be amended; mac_header >= network_header
is not enough (verified with a new test, see next patch).

Fixes: fd18942244 ("bpf: Don't redirect packets with invalid pkt_len")
Signed-off-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/20221121180340.1983627-1-sdf@google.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Stanislav Fomichev 2022-11-21 10:03:39 -08:00 committed by Greg Kroah-Hartman
parent 7e32686f3e
commit b0e6f769d0
2 changed files with 6 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
net/bpf/test_run.c
View File

@ -939,9 +939,6 @@ static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb)
{
struct qdisc_skb_cb *cb = (struct qdisc_skb_cb *)skb->cb;
if (!skb->len)
return -EINVAL;
if (!__skb)
return 0;

7
net/core/filter.c
View File

@ -2123,6 +2123,11 @@ static int __bpf_redirect_no_mac(struct sk_buff *skb, struct net_device *dev,
{
unsigned int mlen = skb_network_offset(skb);
if (unlikely(skb->len <= mlen)) {
kfree_skb(skb);
return -ERANGE;
}
if (mlen) {
__skb_pull(skb, mlen);
@ -2144,7 +2149,7 @@ static int __bpf_redirect_common(struct sk_buff *skb, struct net_device *dev,
u32 flags)
{
/* Verify that a link layer header is carried */
if (unlikely(skb->mac_header >= skb->network_header)) {
if (unlikely(skb->mac_header >= skb->network_header || skb->len == 0)) {
kfree_skb(skb);
return -ERANGE;
}