[PATCH net] tcp: ulp: fix possible crash in tcp_diag_get_aux_size()

[PATCH net] tcp: ulp: fix possible crash in tcp_diag_get_aux_size()

[Eric Dumazet]

tcp_diag_get_aux_size() can be called with sockets in any state.

icsk_ulp_ops is only present for full sockets.

For SYN_RECV or TIME_WAIT ones we would access garbage.

Fixes: 61723b393292 ("tcp: ulp: add functions to dump ulp-specific information")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Luke Hsiao <lukehsiao@google.com>
Reported-by: Neal Cardwell <ncardwell@google.com>
Cc: Davide Caratti <dcaratti@redhat.com>
---
 net/ipv4/tcp_diag.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/ipv4/tcp_diag.c b/net/ipv4/tcp_diag.c
index babc156deabb573f11bba344215d2c3712c4a3cd..81a8221d650a94be53d17354c60ddd0c655eaccf 100644
--- a/net/ipv4/tcp_diag.c
+++ b/net/ipv4/tcp_diag.c
@@ -163,7 +163,7 @@ static size_t tcp_diag_get_aux_size(struct sock *sk, bool net_admin)
 	}
 #endif
 
-	if (net_admin) {
+	if (net_admin && sk_fullsock(sk)) {
 		const struct tcp_ulp_ops *ulp_ops;
 
 		ulp_ops = icsk->icsk_ulp_ops;
-- 
2.23.0.187.g17f5b7556c-goog

Re: [PATCH net] tcp: ulp: fix possible crash in tcp_diag_get_aux_size()

[Eric Dumazet]

On Thu, Sep 5, 2019 at 10:20 PM Eric Dumazet <edumazet@google.com> wrote:
>
> tcp_diag_get_aux_size() can be called with sockets in any state.
>
> icsk_ulp_ops is only present for full sockets.
>
> For SYN_RECV or TIME_WAIT ones we would access garbage.
>
> Fixes: 61723b393292 ("tcp: ulp: add functions to dump ulp-specific information")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: Luke Hsiao <lukehsiao@google.com>
> Reported-by: Neal Cardwell <ncardwell@google.com>
> Cc: Davide Caratti <dcaratti@redhat.com>
> ---

Sorry for the 'net' tag. This patch targets net-next tree only.

Re: [PATCH net] tcp: ulp: fix possible crash in tcp_diag_get_aux_size()

[Davide Caratti]

On Thu, 2019-09-05 at 13:20 -0700, Eric Dumazet wrote:
> tcp_diag_get_aux_size() can be called with sockets in any state.
> 
> icsk_ulp_ops is only present for full sockets.
> 
> For SYN_RECV or TIME_WAIT ones we would access garbage.
> 

hello Eric, 

thanks for fixing this!

Acked-by: Davide Caratti <dcaratti@redhat.com>

Re: [PATCH net] tcp: ulp: fix possible crash in tcp_diag_get_aux_size()

[David Miller]

From: Eric Dumazet <edumazet@google.com>
Date: Thu,  5 Sep 2019 13:20:41 -0700

> tcp_diag_get_aux_size() can be called with sockets in any state.
> 
> icsk_ulp_ops is only present for full sockets.
> 
> For SYN_RECV or TIME_WAIT ones we would access garbage.
> 
> Fixes: 61723b393292 ("tcp: ulp: add functions to dump ulp-specific information")
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> Reported-by: Luke Hsiao <lukehsiao@google.com>
> Reported-by: Neal Cardwell <ncardwell@google.com>

Applied to net-next, thanks Eric.