mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-15 00:04:15 +08:00
aadd435591
Eric reported that syzkaller triggered a splat in tcp_cleanup_ulp()
where assertion sock_owned_by_me() failed. This happened through
inet_csk_prepare_forced_close() first releasing the socket lock,
then calling into tcp_done(newsk) which is called after the
inet_csk_prepare_forced_close() and therefore without the socket
lock held. The sock_owned_by_me() assertion can generally be
removed as the only place where tcp_cleanup_ulp() is called from
now is out of inet_csk_destroy_sock() -> sk->sk_prot->destroy()
where socket is in dead state and unreachable. Therefore, add a
comment why the check is not needed instead.
Fixes: 8b9088f806 ("tcp, ulp: enforce sock_owned_by_me upon ulp init and cleanup")
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
148 lines
3.0 KiB
C
148 lines
3.0 KiB
C
/*
|
|
* Pluggable TCP upper layer protocol support.
|
|
*
|
|
* Copyright (c) 2016-2017, Mellanox Technologies. All rights reserved.
|
|
* Copyright (c) 2016-2017, Dave Watson <davejwatson@fb.com>. All rights reserved.
|
|
*
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/types.h>
|
|
#include <linux/list.h>
|
|
#include <linux/gfp.h>
|
|
#include <net/tcp.h>
|
|
|
|
static DEFINE_SPINLOCK(tcp_ulp_list_lock);
|
|
static LIST_HEAD(tcp_ulp_list);
|
|
|
|
/* Simple linear search, don't expect many entries! */
|
|
static struct tcp_ulp_ops *tcp_ulp_find(const char *name)
|
|
{
|
|
struct tcp_ulp_ops *e;
|
|
|
|
list_for_each_entry_rcu(e, &tcp_ulp_list, list) {
|
|
if (strcmp(e->name, name) == 0)
|
|
return e;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
|
|
static const struct tcp_ulp_ops *__tcp_ulp_find_autoload(const char *name)
|
|
{
|
|
const struct tcp_ulp_ops *ulp = NULL;
|
|
|
|
rcu_read_lock();
|
|
ulp = tcp_ulp_find(name);
|
|
|
|
#ifdef CONFIG_MODULES
|
|
if (!ulp && capable(CAP_NET_ADMIN)) {
|
|
rcu_read_unlock();
|
|
request_module("tcp-ulp-%s", name);
|
|
rcu_read_lock();
|
|
ulp = tcp_ulp_find(name);
|
|
}
|
|
#endif
|
|
if (!ulp || !try_module_get(ulp->owner))
|
|
ulp = NULL;
|
|
|
|
rcu_read_unlock();
|
|
return ulp;
|
|
}
|
|
|
|
/* Attach new upper layer protocol to the list
|
|
* of available protocols.
|
|
*/
|
|
int tcp_register_ulp(struct tcp_ulp_ops *ulp)
|
|
{
|
|
int ret = 0;
|
|
|
|
spin_lock(&tcp_ulp_list_lock);
|
|
if (tcp_ulp_find(ulp->name))
|
|
ret = -EEXIST;
|
|
else
|
|
list_add_tail_rcu(&ulp->list, &tcp_ulp_list);
|
|
spin_unlock(&tcp_ulp_list_lock);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(tcp_register_ulp);
|
|
|
|
void tcp_unregister_ulp(struct tcp_ulp_ops *ulp)
|
|
{
|
|
spin_lock(&tcp_ulp_list_lock);
|
|
list_del_rcu(&ulp->list);
|
|
spin_unlock(&tcp_ulp_list_lock);
|
|
|
|
synchronize_rcu();
|
|
}
|
|
EXPORT_SYMBOL_GPL(tcp_unregister_ulp);
|
|
|
|
/* Build string with list of available upper layer protocl values */
|
|
void tcp_get_available_ulp(char *buf, size_t maxlen)
|
|
{
|
|
struct tcp_ulp_ops *ulp_ops;
|
|
size_t offs = 0;
|
|
|
|
*buf = '\0';
|
|
rcu_read_lock();
|
|
list_for_each_entry_rcu(ulp_ops, &tcp_ulp_list, list) {
|
|
offs += snprintf(buf + offs, maxlen - offs,
|
|
"%s%s",
|
|
offs == 0 ? "" : " ", ulp_ops->name);
|
|
}
|
|
rcu_read_unlock();
|
|
}
|
|
|
|
void tcp_cleanup_ulp(struct sock *sk)
|
|
{
|
|
struct inet_connection_sock *icsk = inet_csk(sk);
|
|
|
|
/* No sock_owned_by_me() check here as at the time the
|
|
* stack calls this function, the socket is dead and
|
|
* about to be destroyed.
|
|
*/
|
|
if (!icsk->icsk_ulp_ops)
|
|
return;
|
|
|
|
if (icsk->icsk_ulp_ops->release)
|
|
icsk->icsk_ulp_ops->release(sk);
|
|
module_put(icsk->icsk_ulp_ops->owner);
|
|
|
|
icsk->icsk_ulp_ops = NULL;
|
|
}
|
|
|
|
static int __tcp_set_ulp(struct sock *sk, const struct tcp_ulp_ops *ulp_ops)
|
|
{
|
|
struct inet_connection_sock *icsk = inet_csk(sk);
|
|
int err;
|
|
|
|
err = -EEXIST;
|
|
if (icsk->icsk_ulp_ops)
|
|
goto out_err;
|
|
|
|
err = ulp_ops->init(sk);
|
|
if (err)
|
|
goto out_err;
|
|
|
|
icsk->icsk_ulp_ops = ulp_ops;
|
|
return 0;
|
|
out_err:
|
|
module_put(ulp_ops->owner);
|
|
return err;
|
|
}
|
|
|
|
int tcp_set_ulp(struct sock *sk, const char *name)
|
|
{
|
|
const struct tcp_ulp_ops *ulp_ops;
|
|
|
|
sock_owned_by_me(sk);
|
|
|
|
ulp_ops = __tcp_ulp_find_autoload(name);
|
|
if (!ulp_ops)
|
|
return -ENOENT;
|
|
|
|
return __tcp_set_ulp(sk, ulp_ops);
|
|
}
|