diff options
| author | Yan Zhai <yan@cloudflare.com> | 2023-08-18 05:58:14 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-09-23 11:46:55 +0300 |
| commit | 81bc20da188ab8022b505e9611abedf62071fed1 (patch) | |
| tree | 198504c40eabf8f5dc27bdb68054a29adcd181d7 | |
| parent | cf560871324f2d434e356af72ab9a4ce4495fcfc (diff) | |
| download | linux-81bc20da188ab8022b505e9611abedf62071fed1.tar.xz | |
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 d747ef975cd8..0ab4647ccc24 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 c5c9dc0f41cb..c242c412dabc 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 36647d321107..c9322e6a1c0c 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; } |