diff options
| author | Yan Zhai <yan@cloudflare.com> | 2023-08-17 19:58:14 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-09-23 10:48:01 +0200 |
| commit | 6d1c51798519a5877b8fd8078fc02b6317c3810f (patch) | |
| tree | 7375d522e17238473a4d3034ebaf0ae32fad982e | |
| parent | e01260bd4185fca1e33e5bde856fc0fc73c42ac3 (diff) | |
lwt: Check LWTUNNEL_XMIT_CONTINUE strictly
[ Upstream commit a171fbec88a2c730b108c7147ac5e7b2f5a02b47 ]
LWTUNNEL_XMIT_CONTINUE is implicitly assumed in ip(6)_finish_output2,
such that any positive return value from a xmit hook could cause
unexpected continue behavior, despite that related skb may have been
freed. This could be error-prone for future xmit hook ops. One of the
possible errors is to return statuses of dst_output directly.
To make the code safer, redefine LWTUNNEL_XMIT_CONTINUE value to
distinguish from dst_output statuses and check the continue
condition explicitly.
Fixes: 3a0af8fd61f9 ("bpf: BPF for lightweight tunnel infrastructure")
Suggested-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Yan Zhai <yan@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/96b939b85eda00e8df4f7c080f770970a4c5f698.1692326837.git.yan@cloudflare.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | include/net/lwtunnel.h | 5 | ||||
| -rw-r--r-- | net/ipv4/ip_output.c | 2 | ||||
| -rw-r--r-- | net/ipv6/ip6_output.c | 2 |
3 files changed, 6 insertions, 3 deletions
diff --git a/include/net/lwtunnel.h b/include/net/lwtunnel.h index 33fd9ba7e0e5..ec75c0a1c529 100644 --- a/include/net/lwtunnel.h +++ b/include/net/lwtunnel.h @@ -16,9 +16,12 @@ #define LWTUNNEL_STATE_INPUT_REDIRECT BIT(1) #define LWTUNNEL_STATE_XMIT_REDIRECT BIT(2) +/* LWTUNNEL_XMIT_CONTINUE should be distinguishable from dst_output return + * values (NET_XMIT_xxx and NETDEV_TX_xxx in linux/netdevice.h) for safety. + */ enum { LWTUNNEL_XMIT_DONE, - LWTUNNEL_XMIT_CONTINUE, + LWTUNNEL_XMIT_CONTINUE = 0x100, }; diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 92fa11e75a4d..6936f703758b 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -221,7 +221,7 @@ static int ip_finish_output2(struct net *net, struct sock *sk, struct sk_buff *s if (lwtunnel_xmit_redirect(dst->lwtstate)) { int res = lwtunnel_xmit(skb); - if (res < 0 || res == LWTUNNEL_XMIT_DONE) + if (res != LWTUNNEL_XMIT_CONTINUE) return res; } diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 4f31a781ab37..ff4d349e13f7 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -106,7 +106,7 @@ static int ip6_finish_output2(struct net *net, struct sock *sk, struct sk_buff * if (lwtunnel_xmit_redirect(dst->lwtstate)) { int res = lwtunnel_xmit(skb); - if (res < 0 || res == LWTUNNEL_XMIT_DONE) + if (res != LWTUNNEL_XMIT_CONTINUE) return res; } |