| Message ID | 1463588367-16310-1-git-send-email-aryabinin@virtuozzo.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On Wed, 2016-05-18 at 19:19 +0300, Andrey Ryabinin wrote: > ->sk_shutdown bits share one bitfield with some other bits in sock struct, > such as ->sk_no_check_[r,t]x, ->sk_userlocks ... > sock_setsockopt() may write to these bits, while holding the socket lock. > > In case of AF_UNIX sockets, we change ->sk_shutdown bits while holding only > unix_state_lock(). So concurrent setsockopt() and shutdown() may lead > to corrupting these bits. > > Fix this by moving ->sk_shutdown bits out of bitfield into a separate byte. > This will not change the 'struct sock' size since ->sk_shutdown moved into > previously unused 16-bit hole. > > Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> > Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org> > --- Acked-by: Eric Dumazet <edumazet@google.com>
From: Andrey Ryabinin <aryabinin@virtuozzo.com> Date: Wed, 18 May 2016 19:19:27 +0300 > ->sk_shutdown bits share one bitfield with some other bits in sock struct, > such as ->sk_no_check_[r,t]x, ->sk_userlocks ... > sock_setsockopt() may write to these bits, while holding the socket lock. > > In case of AF_UNIX sockets, we change ->sk_shutdown bits while holding only > unix_state_lock(). So concurrent setsockopt() and shutdown() may lead > to corrupting these bits. > > Fix this by moving ->sk_shutdown bits out of bitfield into a separate byte. > This will not change the 'struct sock' size since ->sk_shutdown moved into > previously unused 16-bit hole. > > Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> > Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Looks good, applied and queued up for -stable. Thanks.
diff --git a/include/net/sock.h b/include/net/sock.h index c9c8b19..649d2a8 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -382,8 +382,13 @@ struct sock { atomic_t sk_omem_alloc; int sk_sndbuf; struct sk_buff_head sk_write_queue; + + /* + * Because of non atomicity rules, all + * changes are protected by socket lock. + */ kmemcheck_bitfield_begin(flags); - unsigned int sk_shutdown : 2, + unsigned int sk_padding : 2, sk_no_check_tx : 1, sk_no_check_rx : 1, sk_userlocks : 4, @@ -391,6 +396,7 @@ struct sock { sk_type : 16; #define SK_PROTOCOL_MAX U8_MAX kmemcheck_bitfield_end(flags); + int sk_wmem_queued; gfp_t sk_allocation; u32 sk_pacing_rate; /* bytes per second */ @@ -418,6 +424,7 @@ struct sock { struct timer_list sk_timer; ktime_t sk_stamp; u16 sk_tsflags; + u8 sk_shutdown; u32 sk_tskey; struct socket *sk_socket; void *sk_user_data;
->sk_shutdown bits share one bitfield with some other bits in sock struct, such as ->sk_no_check_[r,t]x, ->sk_userlocks ... sock_setsockopt() may write to these bits, while holding the socket lock. In case of AF_UNIX sockets, we change ->sk_shutdown bits while holding only unix_state_lock(). So concurrent setsockopt() and shutdown() may lead to corrupting these bits. Fix this by moving ->sk_shutdown bits out of bitfield into a separate byte. This will not change the 'struct sock' size since ->sk_shutdown moved into previously unused 16-bit hole. Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Suggested-by: Hannes Frederic Sowa <hannes@stressinduktion.org> --- Changes since v1: - move sk_shutdown into a separate byte instead of locking AF_UNIX sockets. Changes since v2: - reorder bitfields, so that sk_type/sk_protocol still fit in separate 2-bytes/byte. Changes since v3: - padding and comment per Eric. include/net/sock.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)