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Commit fc64869c authored by Andrey Ryabinin's avatar Andrey Ryabinin Committed by David S. Miller
Browse files

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



->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: default avatarAndrey Ryabinin <aryabinin@virtuozzo.com>
Suggested-by: default avatarHannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 911f6b1f

include/net/sock.h

+8 −1
Original line number Diff line number Diff line
@@ -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;