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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org, Hannes Reinecke <hare@suse.com>,
	"David S. Miller" <davem@davemloft.net>,
	Jens Axboe <axboe@kernel.dk>
Subject: [PATCH 4.14 03/38] net: split out functions related to registering inflight socket files
Date: Mon,  2 Aug 2021 15:44:25 +0200	[thread overview]
Message-ID: <20210802134334.943615462@linuxfoundation.org> (raw)
In-Reply-To: <20210802134334.835358048@linuxfoundation.org>

From: Jens Axboe <axboe@kernel.dk>

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: Hannes Reinecke <hare@suse.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
[ backported to older kernels to get access to unix_gc_lock - gregkh ]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 include/net/af_unix.h |    1 
 net/Makefile          |    2 
 net/unix/Kconfig      |    5 +
 net/unix/Makefile     |    2 
 net/unix/af_unix.c    |   63 ---------------------
 net/unix/garbage.c    |   68 ----------------------
 net/unix/scm.c        |  149 ++++++++++++++++++++++++++++++++++++++++++++++++++
 net/unix/scm.h        |   10 +++
 8 files changed, 172 insertions(+), 128 deletions(-)
 create mode 100644 net/unix/scm.c
 create mode 100644 net/unix/scm.h

--- a/include/net/af_unix.h
+++ b/include/net/af_unix.h
@@ -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);
--- a/net/Makefile
+++ b/net/Makefile
@@ -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_PACKET)		+= packet/
 obj-$(CONFIG_NET_KEY)		+= key/
--- a/net/unix/Kconfig
+++ b/net/unix/Kconfig
@@ -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
--- a/net/unix/Makefile
+++ b/net/unix/Makefile
@@ -10,3 +10,5 @@ unix-$(CONFIG_SYSCTL)	+= sysctl_net_unix
 
 obj-$(CONFIG_UNIX_DIAG)	+= unix_diag.o
 unix_diag-y		:= diag.o
+
+obj-$(CONFIG_UNIX_SCM)	+= scm.o
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -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);
@@ -1519,67 +1521,6 @@ out:
 	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;
--- a/net/unix/garbage.c
+++ b/net/unix/garbage.c
@@ -86,77 +86,13 @@
 #include <net/scm.h>
 #include <net/tcp_states.h>
 
+#include "scm.h"
+
 /* Internal data structures and random procedures: */
 
-static LIST_HEAD(gc_inflight_list);
 static LIST_HEAD(gc_candidates);
-static DEFINE_SPINLOCK(unix_gc_lock);
 static DECLARE_WAIT_QUEUE_HEAD(unix_gc_wait);
 
-unsigned int unix_tot_inflight;
-
-struct sock *unix_get_socket(struct file *filp)
-{
-	struct sock *u_sock = NULL;
-	struct inode *inode = file_inode(filp);
-
-	/* Socket ? */
-	if (S_ISSOCK(inode->i_mode) && !(filp->f_mode & FMODE_PATH)) {
-		struct socket *sock = SOCKET_I(inode);
-		struct sock *s = sock->sk;
-
-		/* PF_UNIX ? */
-		if (s && sock->ops && sock->ops->family == PF_UNIX)
-			u_sock = s;
-	}
-	return u_sock;
-}
-
-/* Keep the number of times in flight count for the file
- * descriptor if it is for an AF_UNIX socket.
- */
-
-void unix_inflight(struct user_struct *user, struct file *fp)
-{
-	struct sock *s = unix_get_socket(fp);
-
-	spin_lock(&unix_gc_lock);
-
-	if (s) {
-		struct unix_sock *u = unix_sk(s);
-
-		if (atomic_long_inc_return(&u->inflight) == 1) {
-			BUG_ON(!list_empty(&u->link));
-			list_add_tail(&u->link, &gc_inflight_list);
-		} else {
-			BUG_ON(list_empty(&u->link));
-		}
-		unix_tot_inflight++;
-	}
-	user->unix_inflight++;
-	spin_unlock(&unix_gc_lock);
-}
-
-void unix_notinflight(struct user_struct *user, struct file *fp)
-{
-	struct sock *s = unix_get_socket(fp);
-
-	spin_lock(&unix_gc_lock);
-
-	if (s) {
-		struct unix_sock *u = unix_sk(s);
-
-		BUG_ON(!atomic_long_read(&u->inflight));
-		BUG_ON(list_empty(&u->link));
-
-		if (atomic_long_dec_and_test(&u->inflight))
-			list_del_init(&u->link);
-		unix_tot_inflight--;
-	}
-	user->unix_inflight--;
-	spin_unlock(&unix_gc_lock);
-}
-
 static void scan_inflight(struct sock *x, void (*func)(struct unix_sock *),
 			  struct sk_buff_head *hitlist)
 {
--- /dev/null
+++ b/net/unix/scm.c
@@ -0,0 +1,149 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/socket.h>
+#include <linux/net.h>
+#include <linux/fs.h>
+#include <net/af_unix.h>
+#include <net/scm.h>
+#include <linux/init.h>
+#include <linux/sched/signal.h>
+
+#include "scm.h"
+
+unsigned int unix_tot_inflight;
+EXPORT_SYMBOL(unix_tot_inflight);
+
+LIST_HEAD(gc_inflight_list);
+EXPORT_SYMBOL(gc_inflight_list);
+
+DEFINE_SPINLOCK(unix_gc_lock);
+EXPORT_SYMBOL(unix_gc_lock);
+
+struct sock *unix_get_socket(struct file *filp)
+{
+	struct sock *u_sock = NULL;
+	struct inode *inode = file_inode(filp);
+
+	/* Socket ? */
+	if (S_ISSOCK(inode->i_mode) && !(filp->f_mode & FMODE_PATH)) {
+		struct socket *sock = SOCKET_I(inode);
+		struct sock *s = sock->sk;
+
+		/* PF_UNIX ? */
+		if (s && sock->ops && sock->ops->family == PF_UNIX)
+			u_sock = s;
+	}
+	return u_sock;
+}
+EXPORT_SYMBOL(unix_get_socket);
+
+/* Keep the number of times in flight count for the file
+ * descriptor if it is for an AF_UNIX socket.
+ */
+void unix_inflight(struct user_struct *user, struct file *fp)
+{
+	struct sock *s = unix_get_socket(fp);
+
+	spin_lock(&unix_gc_lock);
+
+	if (s) {
+		struct unix_sock *u = unix_sk(s);
+
+		if (atomic_long_inc_return(&u->inflight) == 1) {
+			BUG_ON(!list_empty(&u->link));
+			list_add_tail(&u->link, &gc_inflight_list);
+		} else {
+			BUG_ON(list_empty(&u->link));
+		}
+		unix_tot_inflight++;
+	}
+	user->unix_inflight++;
+	spin_unlock(&unix_gc_lock);
+}
+
+void unix_notinflight(struct user_struct *user, struct file *fp)
+{
+	struct sock *s = unix_get_socket(fp);
+
+	spin_lock(&unix_gc_lock);
+
+	if (s) {
+		struct unix_sock *u = unix_sk(s);
+
+		BUG_ON(!atomic_long_read(&u->inflight));
+		BUG_ON(list_empty(&u->link));
+
+		if (atomic_long_dec_and_test(&u->inflight))
+			list_del_init(&u->link);
+		unix_tot_inflight--;
+	}
+	user->unix_inflight--;
+	spin_unlock(&unix_gc_lock);
+}
+
+/*
+ * 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;
+}
+
+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;
+}
+EXPORT_SYMBOL(unix_attach_fds);
+
+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]);
+}
+EXPORT_SYMBOL(unix_detach_fds);
+
+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);
+}
+EXPORT_SYMBOL(unix_destruct_scm);
--- /dev/null
+++ b/net/unix/scm.h
@@ -0,0 +1,10 @@
+#ifndef NET_UNIX_SCM_H
+#define NET_UNIX_SCM_H
+
+extern struct list_head gc_inflight_list;
+extern spinlock_t unix_gc_lock;
+
+int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb);
+void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb);
+
+#endif



  parent reply	other threads:[~2021-08-02 13:52 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-02 13:44 [PATCH 4.14 00/38] 4.14.242-rc1 review Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 01/38] selftest: fix build error in tools/testing/selftests/vm/userfaultfd.c Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 02/38] KVM: x86: determine if an exception has an error code only when injecting it Greg Kroah-Hartman
2021-08-02 13:44 ` Greg Kroah-Hartman [this message]
2021-08-02 13:44 ` [PATCH 4.14 04/38] af_unix: fix garbage collect vs MSG_PEEK Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 05/38] workqueue: fix UAF in pwq_unbound_release_workfn() Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 06/38] net/802/mrp: fix memleak in mrp_request_join() Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 07/38] net/802/garp: fix memleak in garp_request_join() Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 08/38] net: annotate data race around sk_ll_usec Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 09/38] sctp: move 198 addresses from unusable to private scope Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 10/38] hfs: add missing clean-up in hfs_fill_super Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 11/38] hfs: fix high memory mapping in hfs_bnode_read Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 12/38] hfs: add lock nesting notation to hfs_find_init Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 13/38] ARM: dts: versatile: Fix up interrupt controller node names Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 14/38] virtio_net: Do not pull payload in skb->head Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 15/38] gro: ensure frag0 meets IP header alignment Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 16/38] x86/kvm: fix vcpu-id indexed array sizes Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 17/38] ocfs2: fix zero out valid data Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 18/38] ocfs2: issue zeroout to EOF blocks Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 19/38] can: raw: raw_setsockopt(): fix raw_rcv panic for sock UAF Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 20/38] can: mcba_usb_start(): add missing urb->transfer_dma initialization Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 21/38] can: usb_8dev: fix memory leak Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 22/38] can: ems_usb: " Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 23/38] can: esd_usb2: " Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 24/38] NIU: fix incorrect error return, missed in previous revert Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 25/38] nfc: nfcsim: fix use after free during module unload Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 26/38] x86/asm: Ensure asm/proto.h can be included stand-alone Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 27/38] cfg80211: Fix possible memory leak in function cfg80211_bss_update Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 28/38] netfilter: conntrack: adjust stop timestamp to real expiry value Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 29/38] netfilter: nft_nat: allow to specify layer 4 protocol NAT only Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 30/38] tipc: fix sleeping in tipc accept routine Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 31/38] mlx4: Fix missing error code in mlx4_load_one() Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 32/38] net: llc: fix skb_over_panic Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 33/38] net/mlx5: Fix flow table chaining Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 34/38] sctp: fix return value check in __sctp_rcv_asconf_lookup Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 35/38] tulip: windbond-840: Fix missing pci_disable_device() in probe and remove Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 36/38] sis900: " Greg Kroah-Hartman
2021-08-02 13:44 ` [PATCH 4.14 37/38] can: hi311x: fix a signedness bug in hi3110_cmd() Greg Kroah-Hartman
2021-08-02 13:45 ` [PATCH 4.14 38/38] Revert "perf map: Fix dso->nsinfo refcounting" Greg Kroah-Hartman
2021-08-03 13:17 ` [PATCH 4.14 00/38] 4.14.242-rc1 review Naresh Kamboju
2021-08-03 19:15 ` Guenter Roeck
2021-08-04  2:56 ` Samuel Zou

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