diff options
author | Eric Dumazet <edumazet@google.com> | 2021-06-16 06:42:01 -0700 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2021-06-16 12:48:18 -0700 |
commit | c7d2ef5dd4b03ed0ee1d13bc0c55f9cf62d49bd6 (patch) | |
tree | 7659280ecb32e015ddb30451aeadb8eaacdace63 /net/packet | |
parent | e82a35aead2fd6d6df461291e634be07f71364b9 (diff) | |
download | linux-c7d2ef5dd4b03ed0ee1d13bc0c55f9cf62d49bd6.tar.bz2 |
net/packet: annotate accesses to po->bind
tpacket_snd(), packet_snd(), packet_getname() and packet_seq_show()
can read po->num without holding a lock. This means other threads
can change po->num at the same time.
KCSAN complained about this known fact [1]
Add READ_ONCE()/WRITE_ONCE() to address the issue.
[1] BUG: KCSAN: data-race in packet_do_bind / packet_sendmsg
write to 0xffff888131a0dcc0 of 2 bytes by task 24714 on cpu 0:
packet_do_bind+0x3ab/0x7e0 net/packet/af_packet.c:3181
packet_bind+0xc3/0xd0 net/packet/af_packet.c:3255
__sys_bind+0x200/0x290 net/socket.c:1637
__do_sys_bind net/socket.c:1648 [inline]
__se_sys_bind net/socket.c:1646 [inline]
__x64_sys_bind+0x3d/0x50 net/socket.c:1646
do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
entry_SYSCALL_64_after_hwframe+0x44/0xae
read to 0xffff888131a0dcc0 of 2 bytes by task 24719 on cpu 1:
packet_snd net/packet/af_packet.c:2899 [inline]
packet_sendmsg+0x317/0x3570 net/packet/af_packet.c:3040
sock_sendmsg_nosec net/socket.c:654 [inline]
sock_sendmsg net/socket.c:674 [inline]
____sys_sendmsg+0x360/0x4d0 net/socket.c:2350
___sys_sendmsg net/socket.c:2404 [inline]
__sys_sendmsg+0x1ed/0x270 net/socket.c:2433
__do_sys_sendmsg net/socket.c:2442 [inline]
__se_sys_sendmsg net/socket.c:2440 [inline]
__x64_sys_sendmsg+0x42/0x50 net/socket.c:2440
do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
entry_SYSCALL_64_after_hwframe+0x44/0xae
value changed: 0x0000 -> 0x1200
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 24719 Comm: syz-executor.5 Not tainted 5.13.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/packet')
-rw-r--r-- | net/packet/af_packet.c | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 74e6e45a8e84..e91a36bdd1ab 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2683,7 +2683,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg) } if (likely(saddr == NULL)) { dev = packet_cached_dev_get(po); - proto = po->num; + proto = READ_ONCE(po->num); } else { err = -EINVAL; if (msg->msg_namelen < sizeof(struct sockaddr_ll)) @@ -2896,7 +2896,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len) if (likely(saddr == NULL)) { dev = packet_cached_dev_get(po); - proto = po->num; + proto = READ_ONCE(po->num); } else { err = -EINVAL; if (msg->msg_namelen < sizeof(struct sockaddr_ll)) @@ -3171,7 +3171,7 @@ static int packet_do_bind(struct sock *sk, const char *name, int ifindex, /* prevents packet_notifier() from calling * register_prot_hook() */ - po->num = 0; + WRITE_ONCE(po->num, 0); __unregister_prot_hook(sk, true); rcu_read_lock(); dev_curr = po->prot_hook.dev; @@ -3181,7 +3181,7 @@ static int packet_do_bind(struct sock *sk, const char *name, int ifindex, } BUG_ON(po->running); - po->num = proto; + WRITE_ONCE(po->num, proto); po->prot_hook.type = proto; if (unlikely(unlisted)) { @@ -3526,7 +3526,7 @@ static int packet_getname(struct socket *sock, struct sockaddr *uaddr, sll->sll_family = AF_PACKET; sll->sll_ifindex = po->ifindex; - sll->sll_protocol = po->num; + sll->sll_protocol = READ_ONCE(po->num); sll->sll_pkttype = 0; rcu_read_lock(); dev = dev_get_by_index_rcu(sock_net(sk), po->ifindex); @@ -4414,7 +4414,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u, was_running = po->running; num = po->num; if (was_running) { - po->num = 0; + WRITE_ONCE(po->num, 0); __unregister_prot_hook(sk, false); } spin_unlock(&po->bind_lock); @@ -4449,7 +4449,7 @@ static int packet_set_ring(struct sock *sk, union tpacket_req_u *req_u, spin_lock(&po->bind_lock); if (was_running) { - po->num = num; + WRITE_ONCE(po->num, num); register_prot_hook(sk); } spin_unlock(&po->bind_lock); @@ -4619,7 +4619,7 @@ static int packet_seq_show(struct seq_file *seq, void *v) s, refcount_read(&s->sk_refcnt), s->sk_type, - ntohs(po->num), + ntohs(READ_ONCE(po->num)), po->ifindex, po->running, atomic_read(&s->sk_rmem_alloc), |