From: Stanislav Fomichev <sdf@google.com>
To: bpf@vger.kernel.org
Cc: ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
martin.lau@linux.dev, song@kernel.org, yhs@fb.com,
john.fastabend@gmail.com, kpsingh@kernel.org, sdf@google.com,
haoluo@google.com, jolsa@kernel.org
Subject: [PATCH bpf-next 1/2] bpf: Move skb->len == 0 checks into __bpf_redirect
Date: Mon, 14 Nov 2022 19:10:30 -0800 [thread overview]
Message-ID: <20221115031031.3281094-1-sdf@google.com> (raw)
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@google.com>
---
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
next reply other threads:[~2022-11-15 3:10 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-15 3:10 Stanislav Fomichev [this message]
2022-11-15 3:10 ` [PATCH bpf-next 2/2] selftests/bpf: Make sure zero-len skbs aren't redirectable Stanislav Fomichev
2022-11-16 20:38 ` Martin KaFai Lau
2022-11-16 21:02 ` Stanislav Fomichev
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