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net: sock: move ->sk_shutdown out of bitfields.

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->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>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Andrey Ryabinin 2016-05-18 19:19:27 +03:00 committed by David S. Miller
parent 911f6b1f57
commit fc64869c48
1 changed files with 8 additions and 1 deletions
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9
include/net/sock.h
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@ -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;