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: fd1894224407 ("bpf: Don't redirect packets with invalid pkt_len")
Signed-off-by: Stanislav Fomichev <sdf@xxxxxxxxxx>
---
net/bpf/test_run.c | 3 ---
net/core/filter.c | 11 ++++++-----
2 files changed, 6 insertions(+), 8 deletions(-)
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 13d578ce2a09..6fba440efc40 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -979,9 +979,6 @@ 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;
diff --git a/net/core/filter.c b/net/core/filter.c
index 6dd2baf5eeb2..910ccd416465 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -2124,12 +2124,13 @@ 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);
- if (unlikely(!skb->len)) {
- kfree_skb(skb);
- return -ERANGE;
- }
/* At ingress, the mac header has already been pulled once.
* At egress, skb_pospull_rcsum has to be done in case that
@@ -2149,7 +2150,7 @@ 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;
}
--
2.38.1.431.g37b22c650d-goog
