summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorZhengchao Shao <shaozhengchao@huawei.com>2022-07-15 13:55:59 +0200
committerAlexei Starovoitov <ast@kernel.org>2022-07-19 18:50:54 +0200
commitfd1894224407c484f652ad456e1ce423e89bb3eb (patch)
tree9980e1d31ad073231806f842bea8c26e819e7e58
parentMerge branch 'BPF array map fixes and improvements' (diff)
downloadlinux-fd1894224407c484f652ad456e1ce423e89bb3eb.tar.xz
linux-fd1894224407c484f652ad456e1ce423e89bb3eb.zip
bpf: Don't redirect packets with invalid pkt_len
Syzbot found an issue [1]: fq_codel_drop() try to drop a flow whitout any skbs, that is, the flow->head is null. The root cause, as the [2] says, is because that bpf_prog_test_run_skb() run a bpf prog which redirects empty skbs. So we should determine whether the length of the packet modified by bpf prog or others like bpf_prog_test is valid before forwarding it directly. LINK: [1] https://syzkaller.appspot.com/bug?id=0b84da80c2917757915afa89f7738a9d16ec96c5 LINK: [2] https://www.spinics.net/lists/netdev/msg777503.html Reported-by: syzbot+7a12909485b94426aceb@syzkaller.appspotmail.com Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com> Reviewed-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20220715115559.139691-1-shaozhengchao@huawei.com Signed-off-by: Alexei Starovoitov <ast@kernel.org>
-rw-r--r--include/linux/skbuff.h8
-rw-r--r--net/bpf/test_run.c3
-rw-r--r--net/core/dev.c1
3 files changed, 12 insertions, 0 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index f6a27ab19202..82e8368ba6e6 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2459,6 +2459,14 @@ static inline void skb_set_tail_pointer(struct sk_buff *skb, const int offset)
#endif /* NET_SKBUFF_DATA_USES_OFFSET */
+static inline void skb_assert_len(struct sk_buff *skb)
+{
+#ifdef CONFIG_DEBUG_NET
+ if (WARN_ONCE(!skb->len, "%s\n", __func__))
+ DO_ONCE_LITE(skb_dump, KERN_ERR, skb, false);
+#endif /* CONFIG_DEBUG_NET */
+}
+
/*
* Add data to an sk_buff
*/
diff --git a/net/bpf/test_run.c b/net/bpf/test_run.c
index 2ca96acbc50a..dc9dc0bedca0 100644
--- a/net/bpf/test_run.c
+++ b/net/bpf/test_run.c
@@ -955,6 +955,9 @@ 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/dev.c b/net/core/dev.c
index 978ed0622d8f..e241a475036f 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4168,6 +4168,7 @@ int __dev_queue_xmit(struct sk_buff *skb, struct net_device *sb_dev)
bool again = false;
skb_reset_mac_header(skb);
+ skb_assert_len(skb);
if (unlikely(skb_shinfo(skb)->tx_flags & SKBTX_SCHED_TSTAMP))
__skb_tstamp_tx(skb, NULL, NULL, skb->sk, SCM_TSTAMP_SCHED);