diff options
| author | Eric Dumazet <edumazet@google.com> | 2021-06-16 06:42:02 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2021-06-16 12:48:18 -0700 |
| commit | e032f7c9c7cefffcfb79b9fc16c53011d2d9d11f (patch) | |
| tree | 1d03649b387a027ee57fc84984059d0aeaf555dc /net/packet | |
| parent | c7d2ef5dd4b03ed0ee1d13bc0c55f9cf62d49bd6 (diff) | |
net/packet: annotate accesses to po->ifindex
Like prior patch, we need to annotate lockless accesses to po->ifindex
For instance, packet_getname() is reading po->ifindex (twice) while
another thread is able to change po->ifindex.
KCSAN reported:
BUG: KCSAN: data-race in packet_do_bind / packet_getname
write to 0xffff888143ce3cbc of 4 bytes by task 25573 on cpu 1:
packet_do_bind+0x420/0x7e0 net/packet/af_packet.c:3191
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 0xffff888143ce3cbc of 4 bytes by task 25578 on cpu 0:
packet_getname+0x5b/0x1a0 net/packet/af_packet.c:3525
__sys_getsockname+0x10e/0x1a0 net/socket.c:1887
__do_sys_getsockname net/socket.c:1902 [inline]
__se_sys_getsockname net/socket.c:1899 [inline]
__x64_sys_getsockname+0x3e/0x50 net/socket.c:1899
do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47
entry_SYSCALL_64_after_hwframe+0x44/0xae
value changed: 0x00000000 -> 0x00000001
Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 25578 Comm: syz-executor.5 Not tainted 5.13.0-rc6-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, 9 insertions, 7 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index e91a36bdd1ab..330ba68828e7 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -3187,11 +3187,11 @@ static int packet_do_bind(struct sock *sk, const char *name, int ifindex, if (unlikely(unlisted)) { dev_put(dev); po->prot_hook.dev = NULL; - po->ifindex = -1; + WRITE_ONCE(po->ifindex, -1); packet_cached_dev_reset(po); } else { po->prot_hook.dev = dev; - po->ifindex = dev ? dev->ifindex : 0; + WRITE_ONCE(po->ifindex, dev ? dev->ifindex : 0); packet_cached_dev_assign(po, dev); } } @@ -3505,7 +3505,7 @@ static int packet_getname_spkt(struct socket *sock, struct sockaddr *uaddr, uaddr->sa_family = AF_PACKET; memset(uaddr->sa_data, 0, sizeof(uaddr->sa_data)); rcu_read_lock(); - dev = dev_get_by_index_rcu(sock_net(sk), pkt_sk(sk)->ifindex); + dev = dev_get_by_index_rcu(sock_net(sk), READ_ONCE(pkt_sk(sk)->ifindex)); if (dev) strlcpy(uaddr->sa_data, dev->name, sizeof(uaddr->sa_data)); rcu_read_unlock(); @@ -3520,16 +3520,18 @@ static int packet_getname(struct socket *sock, struct sockaddr *uaddr, struct sock *sk = sock->sk; struct packet_sock *po = pkt_sk(sk); DECLARE_SOCKADDR(struct sockaddr_ll *, sll, uaddr); + int ifindex; if (peer) return -EOPNOTSUPP; + ifindex = READ_ONCE(po->ifindex); sll->sll_family = AF_PACKET; - sll->sll_ifindex = po->ifindex; + sll->sll_ifindex = ifindex; 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); + dev = dev_get_by_index_rcu(sock_net(sk), ifindex); if (dev) { sll->sll_hatype = dev->type; sll->sll_halen = dev->addr_len; @@ -4108,7 +4110,7 @@ static int packet_notifier(struct notifier_block *this, } if (msg == NETDEV_UNREGISTER) { packet_cached_dev_reset(po); - po->ifindex = -1; + WRITE_ONCE(po->ifindex, -1); if (po->prot_hook.dev) dev_put(po->prot_hook.dev); po->prot_hook.dev = NULL; @@ -4620,7 +4622,7 @@ static int packet_seq_show(struct seq_file *seq, void *v) refcount_read(&s->sk_refcnt), s->sk_type, ntohs(READ_ONCE(po->num)), - po->ifindex, + READ_ONCE(po->ifindex), po->running, atomic_read(&s->sk_rmem_alloc), from_kuid_munged(seq_user_ns(seq), sock_i_uid(s)), |