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Commit 072dfad5 authored by Jens Axboe's avatar Jens Axboe Committed by PavanKumar S.R
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>
Change-Id: I4e7fa4da3f548b9dadacc8d5782fb1370dbf27b4
Git-commit: db44d020
Git-repo: https://android.googlesource.com/kernel/msm


Signed-off-by: default avatarPavanKumar S.R <quic_pavasr@quicinc.com>
parent 2959ed5e

include/net/af_unix.h

+1 −0
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 


void unix_inflight(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 wait_for_unix_gc(void);

struct sock *unix_get_socket(struct file *filp);

net/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -18,7 +18,7 @@ obj-$(CONFIG_NETFILTER) += netfilter/ 
obj-$(CONFIG_INET)		+= ipv4/

obj-$(CONFIG_TLS)		+= tls/

obj-$(CONFIG_XFRM)		+= xfrm/

obj-$(CONFIG_UNIX)		+= unix/

obj-$(CONFIG_UNIX_SCM)		+= unix/

obj-$(CONFIG_NET)		+= ipv6/

obj-$(CONFIG_BPFILTER)		+= bpfilter/

obj-$(CONFIG_PACKET)		+= packet/

net/unix/Kconfig

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


	  Say Y unless you know what you are doing.



config UNIX_SCM

	bool

	depends on UNIX

	default y



config UNIX_DIAG

	tristate "UNIX: socket monitoring interface"

	depends on UNIX

net/unix/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -10,3 +10,5 @@ unix-$(CONFIG_SYSCTL) += sysctl_net_unix.o 


obj-$(CONFIG_UNIX_DIAG)	+= unix_diag.o

unix_diag-y		:= diag.o



obj-$(CONFIG_UNIX_SCM)	+= scm.o

net/unix/af_unix.c

+2 −61
Original line number Diff line number Diff line
@@ -119,6 +119,8 @@ 
#include <linux/freezer.h>

#include <linux/file.h>



#include "scm.h"



struct hlist_head unix_socket_table[2 * UNIX_HASH_SIZE];

EXPORT_SYMBOL_GPL(unix_socket_table);

DEFINE_SPINLOCK(unix_table_lock);
@@ -1514,67 +1516,6 @@ static int unix_getname(struct socket *sock, struct sockaddr *uaddr, int peer) 
	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;

}



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

{

	int i;



	if (too_many_unix_fds(current))

		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 0;

}



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

{

	int err = 0;