* [PATCH net] rxrpc: Fix possible NULL pointer access in ICMP handling
@ 2019-10-10 14:52 David Howells
2019-10-12 4:21 ` David Miller
` (2 more replies)
0 siblings, 3 replies; 5+ messages in thread
From: David Howells @ 2019-10-10 14:52 UTC (permalink / raw)
To: netdev; +Cc: dhowells, linux-afs, linux-kernel
If an ICMP packet comes in on the UDP socket backing an AF_RXRPC socket as
the UDP socket is being shut down, rxrpc_error_report() may get called to
deal with it after sk_user_data on the UDP socket has been cleared, leading
to a NULL pointer access when this local endpoint record gets accessed.
Fix this by just returning immediately if sk_user_data was NULL.
The oops looks like the following:
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
...
RIP: 0010:rxrpc_error_report+0x1bd/0x6a9
...
Call Trace:
? sock_queue_err_skb+0xbd/0xde
? __udp4_lib_err+0x313/0x34d
__udp4_lib_err+0x313/0x34d
icmp_unreach+0x1ee/0x207
icmp_rcv+0x25b/0x28f
ip_protocol_deliver_rcu+0x95/0x10e
ip_local_deliver+0xe9/0x148
__netif_receive_skb_one_core+0x52/0x6e
process_backlog+0xdc/0x177
net_rx_action+0xf9/0x270
__do_softirq+0x1b6/0x39a
? smpboot_register_percpu_thread+0xce/0xce
run_ksoftirqd+0x1d/0x42
smpboot_thread_fn+0x19e/0x1b3
kthread+0xf1/0xf6
? kthread_delayed_work_timer_fn+0x83/0x83
ret_from_fork+0x24/0x30
Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
Reported-by: syzbot+611164843bd48cc2190c@syzkaller.appspotmail.com
Signed-off-by: David Howells <dhowells@redhat.com>
---
net/rxrpc/peer_event.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c
index c97ebdc043e4..61451281d74a 100644
--- a/net/rxrpc/peer_event.c
+++ b/net/rxrpc/peer_event.c
@@ -151,6 +151,9 @@ void rxrpc_error_report(struct sock *sk)
struct rxrpc_peer *peer;
struct sk_buff *skb;
+ if (unlikely(!local))
+ return;
+
_enter("%p{%d}", sk, local->debug_id);
/* Clear the outstanding error value on the socket so that it doesn't
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH net] rxrpc: Fix possible NULL pointer access in ICMP handling
2019-10-10 14:52 [PATCH net] rxrpc: Fix possible NULL pointer access in ICMP handling David Howells
@ 2019-10-12 4:21 ` David Miller
2019-10-12 10:49 ` Eric Dumazet
2019-10-15 15:50 ` David Howells
2 siblings, 0 replies; 5+ messages in thread
From: David Miller @ 2019-10-12 4:21 UTC (permalink / raw)
To: dhowells; +Cc: netdev, linux-afs, linux-kernel
From: David Howells <dhowells@redhat.com>
Date: Thu, 10 Oct 2019 15:52:34 +0100
> If an ICMP packet comes in on the UDP socket backing an AF_RXRPC socket as
> the UDP socket is being shut down, rxrpc_error_report() may get called to
> deal with it after sk_user_data on the UDP socket has been cleared, leading
> to a NULL pointer access when this local endpoint record gets accessed.
>
> Fix this by just returning immediately if sk_user_data was NULL.
>
> The oops looks like the following:
...
> Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
> Reported-by: syzbot+611164843bd48cc2190c@syzkaller.appspotmail.com
> Signed-off-by: David Howells <dhowells@redhat.com>
Applied and queued up for -stable, thanks.
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH net] rxrpc: Fix possible NULL pointer access in ICMP handling
2019-10-10 14:52 [PATCH net] rxrpc: Fix possible NULL pointer access in ICMP handling David Howells
2019-10-12 4:21 ` David Miller
@ 2019-10-12 10:49 ` Eric Dumazet
2019-10-12 11:06 ` Eric Dumazet
2019-10-15 15:50 ` David Howells
2 siblings, 1 reply; 5+ messages in thread
From: Eric Dumazet @ 2019-10-12 10:49 UTC (permalink / raw)
To: David Howells, netdev; +Cc: linux-afs, linux-kernel
On 10/10/19 7:52 AM, David Howells wrote:
> If an ICMP packet comes in on the UDP socket backing an AF_RXRPC socket as
> the UDP socket is being shut down, rxrpc_error_report() may get called to
> deal with it after sk_user_data on the UDP socket has been cleared, leading
> to a NULL pointer access when this local endpoint record gets accessed.
>
> Fix this by just returning immediately if sk_user_data was NULL.
>
> The oops looks like the following:
>
> #PF: supervisor read access in kernel mode
> #PF: error_code(0x0000) - not-present page
> ...
> RIP: 0010:rxrpc_error_report+0x1bd/0x6a9
> ...
> Call Trace:
> ? sock_queue_err_skb+0xbd/0xde
> ? __udp4_lib_err+0x313/0x34d
> __udp4_lib_err+0x313/0x34d
> icmp_unreach+0x1ee/0x207
> icmp_rcv+0x25b/0x28f
> ip_protocol_deliver_rcu+0x95/0x10e
> ip_local_deliver+0xe9/0x148
> __netif_receive_skb_one_core+0x52/0x6e
> process_backlog+0xdc/0x177
> net_rx_action+0xf9/0x270
> __do_softirq+0x1b6/0x39a
> ? smpboot_register_percpu_thread+0xce/0xce
> run_ksoftirqd+0x1d/0x42
> smpboot_thread_fn+0x19e/0x1b3
> kthread+0xf1/0xf6
> ? kthread_delayed_work_timer_fn+0x83/0x83
> ret_from_fork+0x24/0x30
>
> Fixes: 17926a79320a ("[AF_RXRPC]: Provide secure RxRPC sockets for use by userspace and kernel both")
> Reported-by: syzbot+611164843bd48cc2190c@syzkaller.appspotmail.com
> Signed-off-by: David Howells <dhowells@redhat.com>
> ---
>
> net/rxrpc/peer_event.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c
> index c97ebdc043e4..61451281d74a 100644
> --- a/net/rxrpc/peer_event.c
> +++ b/net/rxrpc/peer_event.c
> @@ -151,6 +151,9 @@ void rxrpc_error_report(struct sock *sk)
> struct rxrpc_peer *peer;
> struct sk_buff *skb;
>
> + if (unlikely(!local))
> + return;
> +
> _enter("%p{%d}", sk, local->debug_id);
>
> /* Clear the outstanding error value on the socket so that it doesn't
>
Okay, but we also need this.
diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c
index c97ebdc043e44525eaecdd54bc447c1895bdca74..38db10e61f7a5cb50f9ee036b5e16ec284e723ac 100644
--- a/net/rxrpc/peer_event.c
+++ b/net/rxrpc/peer_event.c
@@ -145,9 +145,9 @@ static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *se
*/
void rxrpc_error_report(struct sock *sk)
{
+ struct rxrpc_local *local = rcu_dereference_sk_user_data(sk);
struct sock_exterr_skb *serr;
struct sockaddr_rxrpc srx;
- struct rxrpc_local *local = sk->sk_user_data;
struct rxrpc_peer *peer;
struct sk_buff *skb;
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH net] rxrpc: Fix possible NULL pointer access in ICMP handling
2019-10-12 10:49 ` Eric Dumazet
@ 2019-10-12 11:06 ` Eric Dumazet
0 siblings, 0 replies; 5+ messages in thread
From: Eric Dumazet @ 2019-10-12 11:06 UTC (permalink / raw)
To: Eric Dumazet, David Howells, netdev; +Cc: linux-afs, linux-kernel
On 10/12/19 3:49 AM, Eric Dumazet wrote:
>
> Okay, but we also need this.
>
> diff --git a/net/rxrpc/peer_event.c b/net/rxrpc/peer_event.c
> index c97ebdc043e44525eaecdd54bc447c1895bdca74..38db10e61f7a5cb50f9ee036b5e16ec284e723ac 100644
> --- a/net/rxrpc/peer_event.c
> +++ b/net/rxrpc/peer_event.c
> @@ -145,9 +145,9 @@ static void rxrpc_adjust_mtu(struct rxrpc_peer *peer, struct sock_exterr_skb *se
> */
> void rxrpc_error_report(struct sock *sk)
> {
> + struct rxrpc_local *local = rcu_dereference_sk_user_data(sk);
> struct sock_exterr_skb *serr;
> struct sockaddr_rxrpc srx;
> - struct rxrpc_local *local = sk->sk_user_data;
> struct rxrpc_peer *peer;
> struct sk_buff *skb;
>
I will psubmit the patch later once David pushes his net tree, since I do not know yet
the sha1 of your patch (to provide a proper Fixes: tag)
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH net] rxrpc: Fix possible NULL pointer access in ICMP handling
2019-10-10 14:52 [PATCH net] rxrpc: Fix possible NULL pointer access in ICMP handling David Howells
2019-10-12 4:21 ` David Miller
2019-10-12 10:49 ` Eric Dumazet
@ 2019-10-15 15:50 ` David Howells
2 siblings, 0 replies; 5+ messages in thread
From: David Howells @ 2019-10-15 15:50 UTC (permalink / raw)
To: Eric Dumazet; +Cc: dhowells, netdev, linux-afs, linux-kernel
Eric Dumazet <eric.dumazet@gmail.com> wrote:
> void rxrpc_error_report(struct sock *sk)
> {
> + struct rxrpc_local *local = rcu_dereference_sk_user_data(sk);
Acked-by: David Howells <dhowells@redhat.com>
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2019-10-15 15:50 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-10-10 14:52 [PATCH net] rxrpc: Fix possible NULL pointer access in ICMP handling David Howells
2019-10-12 4:21 ` David Miller
2019-10-12 10:49 ` Eric Dumazet
2019-10-12 11:06 ` Eric Dumazet
2019-10-15 15:50 ` David Howells
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).