diff mbox series

[13/13] bpf: Fix use of sk->sk_reuseport from sk_assign

Message ID 20200831040333.6058-14-khalid.elmously@canonical.com
State New
Headers show
Series Requested eBPF improvements | expand

Commit Message

Khalid Elmously Aug. 31, 2020, 4:03 a.m. UTC 
From: Joe Stringer <joe@wand.net.nz>

[ upstream commit 8e368dc72e86ad1e1a612416f32d5ad22dca88bc ]

In testing, we found that for request sockets the sk->sk_reuseport field
may yet be uninitialized, which caused bpf_sk_assign() to randomly
succeed or return -ESOCKTNOSUPPORT when handling the forward ACK in a
three-way handshake.

Fix it by only applying the reuseport check for full sockets.

Fixes: cf7fbe660f2d ("bpf: Add socket assign support")
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20200408033540.10339-1-joe@wand.net.nz
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
---
 net/core/filter.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Kleber Sacilotto de Souza Sept. 3, 2020, 10:58 a.m. UTC | #1 
On 31.08.20 06:03, Khalid Elmously wrote:
> From: Joe Stringer <joe@wand.net.nz>

This patch is missing:

BugLink: https://bugs.launchpad.net/bugs/1887740

> 
> [ upstream commit 8e368dc72e86ad1e1a612416f32d5ad22dca88bc ]
> 
> In testing, we found that for request sockets the sk->sk_reuseport field
> may yet be uninitialized, which caused bpf_sk_assign() to randomly
> succeed or return -ESOCKTNOSUPPORT when handling the forward ACK in a
> three-way handshake.
> 
> Fix it by only applying the reuseport check for full sockets.
> 
> Fixes: cf7fbe660f2d ("bpf: Add socket assign support")
> Signed-off-by: Joe Stringer <joe@wand.net.nz>
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
> Acked-by: Martin KaFai Lau <kafai@fb.com>
> Link: https://lore.kernel.org/bpf/20200408033540.10339-1-joe@wand.net.nz
> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
> Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>
> ---
>  net/core/filter.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/net/core/filter.c b/net/core/filter.c
> index baaeab75327c..a895e272d75e 100644
> --- a/net/core/filter.c
> +++ b/net/core/filter.c
> @@ -5992,7 +5992,7 @@ BPF_CALL_3(bpf_sk_assign, struct sk_buff *, skb, struct sock *, sk, u64, flags)
>  		return -EOPNOTSUPP;
>  	if (unlikely(dev_net(skb->dev) != sock_net(sk)))
>  		return -ENETUNREACH;
> -	if (unlikely(sk->sk_reuseport))
> +	if (unlikely(sk_fullsock(sk) && sk->sk_reuseport))
>  		return -ESOCKTNOSUPPORT;
>  	if (sk_is_refcounted(sk) &&
>  	    unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))
>
diff mbox series

Patch

diff --git a/net/core/filter.c b/net/core/filter.c
index baaeab75327c..a895e272d75e 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -5992,7 +5992,7 @@  BPF_CALL_3(bpf_sk_assign, struct sk_buff *, skb, struct sock *, sk, u64, flags)
 		return -EOPNOTSUPP;
 	if (unlikely(dev_net(skb->dev) != sock_net(sk)))
 		return -ENETUNREACH;
-	if (unlikely(sk->sk_reuseport))
+	if (unlikely(sk_fullsock(sk) && sk->sk_reuseport))
 		return -ESOCKTNOSUPPORT;
 	if (sk_is_refcounted(sk) &&
 	    unlikely(!refcount_inc_not_zero(&sk->sk_refcnt)))