af_unix: Remove CONFIG_UNIX_SCM.
Originally, the code related to garbage collection was all in garbage.c. Commitf4e65870e5("net: split out functions related to registering inflight socket files") moved some functions to scm.c for io_uring and added CONFIG_UNIX_SCM just in case AF_UNIX was built as module. However, since commit97154bcf4d("af_unix: Kconfig: make CONFIG_UNIX bool"), AF_UNIX is no longer built separately. Also, io_uring does not support SCM_RIGHTS now. Let's move the functions back to garbage.c Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Acked-by: Jens Axboe <axboe@kernel.dk> Link: https://lore.kernel.org/r/20240129190435.57228-4-kuniyu@amazon.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Kuniyuki Iwashima
Jakub Kicinski
parent
11498715f2
commit
99a7a5b994
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@ -17,19 +17,20 @@ static inline struct unix_sock *unix_get_socket(struct file *filp)
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}
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#endif
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extern spinlock_t unix_gc_lock;
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extern unsigned int unix_tot_inflight;
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void unix_inflight(struct user_struct *user, struct file *fp);
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void unix_notinflight(struct user_struct *user, struct file *fp);
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void unix_destruct_scm(struct sk_buff *skb);
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void unix_gc(void);
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void wait_for_unix_gc(struct scm_fp_list *fpl);
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struct sock *unix_peer_get(struct sock *sk);
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#define UNIX_HASH_MOD (256 - 1)
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#define UNIX_HASH_SIZE (256 * 2)
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#define UNIX_HASH_BITS 8
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extern unsigned int unix_tot_inflight;
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struct unix_address {
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refcount_t refcnt;
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int len;
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@ -17,7 +17,7 @@ obj-$(CONFIG_NETFILTER) += netfilter/
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obj-$(CONFIG_INET) += ipv4/
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obj-$(CONFIG_TLS) += tls/
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obj-$(CONFIG_XFRM) += xfrm/
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obj-$(CONFIG_UNIX_SCM) += unix/
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obj-$(CONFIG_UNIX) += unix/
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obj-y += ipv6/
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obj-$(CONFIG_PACKET) += packet/
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obj-$(CONFIG_NET_KEY) += key/
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@ -16,11 +16,6 @@ config UNIX
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Say Y unless you know what you are doing.
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config UNIX_SCM
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bool
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depends on UNIX
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default y
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config AF_UNIX_OOB
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bool
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depends on UNIX
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@ -11,5 +11,3 @@ unix-$(CONFIG_BPF_SYSCALL) += unix_bpf.o
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obj-$(CONFIG_UNIX_DIAG) += unix_diag.o
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unix_diag-y := diag.o
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obj-$(CONFIG_UNIX_SCM) += scm.o
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@ -118,8 +118,6 @@
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#include <linux/btf_ids.h>
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#include <linux/bpf-cgroup.h>
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#include "scm.h"
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static atomic_long_t unix_nr_socks;
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static struct hlist_head bsd_socket_buckets[UNIX_HASH_SIZE / 2];
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static spinlock_t bsd_socket_locks[UNIX_HASH_SIZE / 2];
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@ -1790,6 +1788,52 @@ out:
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return err;
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}
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/* The "user->unix_inflight" variable is protected by the garbage
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* collection lock, and we just read it locklessly here. If you go
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* over the limit, there might be a tiny race in actually noticing
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* it across threads. Tough.
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*/
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static inline bool too_many_unix_fds(struct task_struct *p)
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{
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struct user_struct *user = current_user();
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if (unlikely(READ_ONCE(user->unix_inflight) > task_rlimit(p, RLIMIT_NOFILE)))
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return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
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return false;
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}
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static int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
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{
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int i;
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if (too_many_unix_fds(current))
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return -ETOOMANYREFS;
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/* Need to duplicate file references for the sake of garbage
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* collection. Otherwise a socket in the fps might become a
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* candidate for GC while the skb is not yet queued.
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*/
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UNIXCB(skb).fp = scm_fp_dup(scm->fp);
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if (!UNIXCB(skb).fp)
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return -ENOMEM;
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for (i = scm->fp->count - 1; i >= 0; i--)
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unix_inflight(scm->fp->user, scm->fp->fp[i]);
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return 0;
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}
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static void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
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{
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int i;
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scm->fp = UNIXCB(skb).fp;
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UNIXCB(skb).fp = NULL;
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for (i = scm->fp->count - 1; i >= 0; i--)
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unix_notinflight(scm->fp->user, scm->fp->fp[i]);
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}
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static void unix_peek_fds(struct scm_cookie *scm, struct sk_buff *skb)
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{
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scm->fp = scm_fp_dup(UNIXCB(skb).fp);
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@ -1837,6 +1881,21 @@ static void unix_peek_fds(struct scm_cookie *scm, struct sk_buff *skb)
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spin_unlock(&unix_gc_lock);
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}
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static void unix_destruct_scm(struct sk_buff *skb)
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{
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struct scm_cookie scm;
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memset(&scm, 0, sizeof(scm));
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scm.pid = UNIXCB(skb).pid;
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if (UNIXCB(skb).fp)
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unix_detach_fds(&scm, skb);
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/* Alas, it calls VFS */
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/* So fscking what? fput() had been SMP-safe since the last Summer */
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scm_destroy(&scm);
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sock_wfree(skb);
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}
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static int unix_scm_to_skb(struct scm_cookie *scm, struct sk_buff *skb, bool send_fds)
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{
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int err = 0;
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@ -81,11 +81,80 @@
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#include <net/scm.h>
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#include <net/tcp_states.h>
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#include "scm.h"
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struct unix_sock *unix_get_socket(struct file *filp)
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{
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struct inode *inode = file_inode(filp);
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/* Internal data structures and random procedures: */
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/* Socket ? */
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if (S_ISSOCK(inode->i_mode) && !(filp->f_mode & FMODE_PATH)) {
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struct socket *sock = SOCKET_I(inode);
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const struct proto_ops *ops;
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struct sock *sk = sock->sk;
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ops = READ_ONCE(sock->ops);
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/* PF_UNIX ? */
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if (sk && ops && ops->family == PF_UNIX)
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return unix_sk(sk);
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}
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return NULL;
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}
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DEFINE_SPINLOCK(unix_gc_lock);
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unsigned int unix_tot_inflight;
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static LIST_HEAD(gc_candidates);
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static LIST_HEAD(gc_inflight_list);
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/* Keep the number of times in flight count for the file
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* descriptor if it is for an AF_UNIX socket.
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*/
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void unix_inflight(struct user_struct *user, struct file *filp)
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{
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struct unix_sock *u = unix_get_socket(filp);
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spin_lock(&unix_gc_lock);
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if (u) {
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if (!u->inflight) {
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WARN_ON_ONCE(!list_empty(&u->link));
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list_add_tail(&u->link, &gc_inflight_list);
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} else {
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WARN_ON_ONCE(list_empty(&u->link));
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}
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u->inflight++;
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/* Paired with READ_ONCE() in wait_for_unix_gc() */
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WRITE_ONCE(unix_tot_inflight, unix_tot_inflight + 1);
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}
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WRITE_ONCE(user->unix_inflight, user->unix_inflight + 1);
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spin_unlock(&unix_gc_lock);
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}
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void unix_notinflight(struct user_struct *user, struct file *filp)
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{
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struct unix_sock *u = unix_get_socket(filp);
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spin_lock(&unix_gc_lock);
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if (u) {
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WARN_ON_ONCE(!u->inflight);
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WARN_ON_ONCE(list_empty(&u->link));
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u->inflight--;
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if (!u->inflight)
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list_del_init(&u->link);
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/* Paired with READ_ONCE() in wait_for_unix_gc() */
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WRITE_ONCE(unix_tot_inflight, unix_tot_inflight - 1);
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}
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WRITE_ONCE(user->unix_inflight, user->unix_inflight - 1);
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spin_unlock(&unix_gc_lock);
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}
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static void scan_inflight(struct sock *x, void (*func)(struct unix_sock *),
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struct sk_buff_head *hitlist)
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150
net/unix/scm.c
150
net/unix/scm.c
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@ -1,150 +0,0 @@
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <linux/string.h>
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#include <linux/socket.h>
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#include <linux/net.h>
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#include <linux/fs.h>
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#include <net/af_unix.h>
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#include <net/scm.h>
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#include <linux/init.h>
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#include <linux/io_uring.h>
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#include "scm.h"
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unsigned int unix_tot_inflight;
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EXPORT_SYMBOL(unix_tot_inflight);
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LIST_HEAD(gc_inflight_list);
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EXPORT_SYMBOL(gc_inflight_list);
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DEFINE_SPINLOCK(unix_gc_lock);
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EXPORT_SYMBOL(unix_gc_lock);
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struct unix_sock *unix_get_socket(struct file *filp)
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{
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struct inode *inode = file_inode(filp);
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/* Socket ? */
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if (S_ISSOCK(inode->i_mode) && !(filp->f_mode & FMODE_PATH)) {
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struct socket *sock = SOCKET_I(inode);
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const struct proto_ops *ops = READ_ONCE(sock->ops);
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struct sock *s = sock->sk;
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/* PF_UNIX ? */
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if (s && ops && ops->family == PF_UNIX)
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return unix_sk(s);
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}
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return NULL;
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}
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EXPORT_SYMBOL(unix_get_socket);
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/* Keep the number of times in flight count for the file
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* descriptor if it is for an AF_UNIX socket.
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*/
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void unix_inflight(struct user_struct *user, struct file *fp)
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{
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struct unix_sock *u = unix_get_socket(fp);
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spin_lock(&unix_gc_lock);
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if (u) {
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if (!u->inflight) {
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WARN_ON_ONCE(!list_empty(&u->link));
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list_add_tail(&u->link, &gc_inflight_list);
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} else {
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WARN_ON_ONCE(list_empty(&u->link));
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}
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u->inflight++;
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/* Paired with READ_ONCE() in wait_for_unix_gc() */
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WRITE_ONCE(unix_tot_inflight, unix_tot_inflight + 1);
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}
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WRITE_ONCE(user->unix_inflight, user->unix_inflight + 1);
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spin_unlock(&unix_gc_lock);
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}
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void unix_notinflight(struct user_struct *user, struct file *fp)
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{
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struct unix_sock *u = unix_get_socket(fp);
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spin_lock(&unix_gc_lock);
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if (u) {
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WARN_ON_ONCE(!u->inflight);
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WARN_ON_ONCE(list_empty(&u->link));
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u->inflight--;
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if (!u->inflight)
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list_del_init(&u->link);
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/* Paired with READ_ONCE() in wait_for_unix_gc() */
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WRITE_ONCE(unix_tot_inflight, unix_tot_inflight - 1);
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}
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WRITE_ONCE(user->unix_inflight, user->unix_inflight - 1);
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spin_unlock(&unix_gc_lock);
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}
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/*
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* The "user->unix_inflight" variable is protected by the garbage
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* collection lock, and we just read it locklessly here. If you go
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* over the limit, there might be a tiny race in actually noticing
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* it across threads. Tough.
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*/
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static inline bool too_many_unix_fds(struct task_struct *p)
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{
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struct user_struct *user = current_user();
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if (unlikely(READ_ONCE(user->unix_inflight) > task_rlimit(p, RLIMIT_NOFILE)))
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return !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN);
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return false;
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}
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int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb)
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{
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int i;
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if (too_many_unix_fds(current))
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return -ETOOMANYREFS;
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/*
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* Need to duplicate file references for the sake of garbage
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* collection. Otherwise a socket in the fps might become a
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* candidate for GC while the skb is not yet queued.
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*/
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UNIXCB(skb).fp = scm_fp_dup(scm->fp);
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if (!UNIXCB(skb).fp)
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return -ENOMEM;
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for (i = scm->fp->count - 1; i >= 0; i--)
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unix_inflight(scm->fp->user, scm->fp->fp[i]);
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return 0;
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}
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EXPORT_SYMBOL(unix_attach_fds);
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void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb)
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{
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int i;
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scm->fp = UNIXCB(skb).fp;
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UNIXCB(skb).fp = NULL;
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for (i = scm->fp->count-1; i >= 0; i--)
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unix_notinflight(scm->fp->user, scm->fp->fp[i]);
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}
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EXPORT_SYMBOL(unix_detach_fds);
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void unix_destruct_scm(struct sk_buff *skb)
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{
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struct scm_cookie scm;
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memset(&scm, 0, sizeof(scm));
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scm.pid = UNIXCB(skb).pid;
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if (UNIXCB(skb).fp)
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unix_detach_fds(&scm, skb);
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/* Alas, it calls VFS */
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/* So fscking what? fput() had been SMP-safe since the last Summer */
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scm_destroy(&scm);
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sock_wfree(skb);
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}
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EXPORT_SYMBOL(unix_destruct_scm);
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@ -1,10 +0,0 @@
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#ifndef NET_UNIX_SCM_H
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#define NET_UNIX_SCM_H
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extern struct list_head gc_inflight_list;
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extern spinlock_t unix_gc_lock;
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int unix_attach_fds(struct scm_cookie *scm, struct sk_buff *skb);
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void unix_detach_fds(struct scm_cookie *scm, struct sk_buff *skb);
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#endif
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