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Commit e32d008d authored by Jens Axboe's avatar Jens Axboe Committed by Karsten Tausche
Browse files

net: split out functions related to registering inflight socket files 



commit f4e65870e5cede5ca1ec0006b6c9803994e5f7b8 upstream.

We need this functionality for the io_uring file registration, but
we cannot rely on it since CONFIG_UNIX can be modular. Move the helpers
to a separate file, that's always builtin to the kernel if CONFIG_UNIX is
m/y.

No functional changes in this patch, just moving code around.

Reviewed-by: default avatarHannes Reinecke <hare@suse.com>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
[ backported to older kernels to get access to unix_gc_lock - gregkh ]
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 1f02ba8b)
Change-Id: I40583ea11ea321bde97ee49545a10936ade3260d
parent 0c36db77

include/net/af_unix.h

+1 −0
Original line number Original line Diff line number Diff line
@@ -8,6 +8,7 @@ 




void unix_inflight(struct user_struct *user, struct file *fp);

void unix_inflight(struct user_struct *user, struct file *fp);

void unix_notinflight(struct user_struct *user, struct file *fp);

void unix_notinflight(struct user_struct *user, struct file *fp);

void unix_destruct_scm(struct sk_buff *skb);

void unix_gc(void);

void unix_gc(void);

void wait_for_unix_gc(void);

void wait_for_unix_gc(void);

struct sock *unix_get_socket(struct file *filp);

struct sock *unix_get_socket(struct file *filp);

net/Makefile

+1 −1
Original line number Original line Diff line number Diff line
@@ -16,7 +16,7 @@ obj-$(CONFIG_NET) += ethernet/ 802/ sched/ netlink/ 
obj-$(CONFIG_NETFILTER)		+= netfilter/

obj-$(CONFIG_NETFILTER)		+= netfilter/

obj-$(CONFIG_INET)		+= ipv4/

obj-$(CONFIG_INET)		+= ipv4/

obj-$(CONFIG_XFRM)		+= xfrm/

obj-$(CONFIG_XFRM)		+= xfrm/

obj-$(CONFIG_UNIX)		+= unix/

obj-$(CONFIG_UNIX_SCM)		+= unix/

obj-$(CONFIG_NET)		+= ipv6/

obj-$(CONFIG_NET)		+= ipv6/

obj-$(CONFIG_PACKET)		+= packet/

obj-$(CONFIG_PACKET)		+= packet/

obj-$(CONFIG_NET_KEY)		+= key/

obj-$(CONFIG_NET_KEY)		+= key/

net/unix/Kconfig

+5 −0
Original line number Original line Diff line number Diff line
@@ -19,6 +19,11 @@ config UNIX 




	  Say Y unless you know what you are doing.

	  Say Y unless you know what you are doing.





config UNIX_SCM

	bool

	depends on UNIX

	default y



config UNIX_DIAG

config UNIX_DIAG

	tristate "UNIX: socket monitoring interface"

	tristate "UNIX: socket monitoring interface"

	depends on UNIX

	depends on UNIX

net/unix/Makefile

+2 −0
Original line number Original line Diff line number Diff line
@@ -9,3 +9,5 @@ unix-$(CONFIG_SYSCTL) += sysctl_net_unix.o 




obj-$(CONFIG_UNIX_DIAG)	+= unix_diag.o

obj-$(CONFIG_UNIX_DIAG)	+= unix_diag.o

unix_diag-y		:= diag.o

unix_diag-y		:= diag.o



obj-$(CONFIG_UNIX_SCM)	+= scm.o

net/unix/af_unix.c

+2 −74
Original line number Original line Diff line number Diff line
@@ -118,6 +118,8 @@ 
#include <linux/security.h>

#include <linux/security.h>

#include <linux/freezer.h>

#include <linux/freezer.h>





#include "scm.h"



struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];

struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];

EXPORT_SYMBOL_GPL(unix_socket_table);

EXPORT_SYMBOL_GPL(unix_socket_table);

DEFINE_SPINLOCK(unix_table_lock);

DEFINE_SPINLOCK(unix_table_lock);
@@ -1505,80 +1507,6 @@ static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int *uaddr_ 
	return err;

	return err;

}

}





static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)

{

	int i;



	scm->fp = UNIXCB(skb).fp;

	UNIXCB(skb).fp = NULL;



	for (i = scm->fp->count-1; i >= 0; i--)

		unix_notinflight(scm->fp->user, scm->fp->fp[i]);

}



static void unix_destruct_scm(struct sk_buff *skb)

{

	struct scm_cookie scm;

	memset(&scm, 0, sizeof(scm));

	scm.pid  = UNIXCB(skb).pid;

	if (UNIXCB(skb).fp)

		unix_detach_fds(&scm, skb);



	/* Alas, it calls VFS */

	/* So fscking what? fput() had been SMP-safe since the last Summer */

	scm_destroy(&scm);

	sock_wfree(skb);

}



/*

 * The "user->unix_inflight" variable is protected by the garbage

 * collection lock, and we just read it locklessly here. If you go

 * over the limit, there might be a tiny race in actually noticing

 * it across threads. Tough.

 */

static inline bool too_many_unix_fds(struct task_struct *p)

{

	struct user_struct *user = current_user();



	if (unlikely(user->unix_inflight > task_rlimit(p, RLIMIT_NOFILE)))

		return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);

	return false;

}



#define MAX_RECURSION_LEVEL 4



static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)

{

	int i;

	unsigned char max_level = 0;



	if (too_many_unix_fds(current))

		return -ETOOMANYREFS;



	for (i = scm->fp->count - 1; i >= 0; i--) {

		struct sock *sk = unix_get_socket(scm->fp->fp[i]);



		if (sk)

			max_level = max(max_level,

					unix_sk(sk)->recursion_level);

	}

	if (unlikely(max_level > MAX_RECURSION_LEVEL))

		return -ETOOMANYREFS;



	/*

	 * Need to duplicate file references for the sake of garbage

	 * collection.  Otherwise a socket in the fps might become a

	 * candidate for GC while the skb is not yet queued.

	 */

	UNIXCB(skb).fp = scm_fp_dup(scm->fp);

	if (!UNIXCB(skb).fp)

		return -ENOMEM;



	for (i = scm->fp->count - 1; i >= 0; i--)

		unix_inflight(scm->fp->user, scm->fp->fp[i]);

	return max_level;

}



static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)

static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)

{

{

	int err = 0;

	int err = 0;