From: Eric Dumazet edumazet@google.com
stable inclusion from stable-5.10.47 commit 08c389de6d53ce6055573e4edd4e2010d1789f05 bugzilla: 172973 https://gitee.com/openeuler/kernel/issues/I4DAKB
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit dcd01eeac14486b56a790f5cce9b823440ba5b34 ]
Both functions are known to be racy when reading inet_num as we do not want to grab locks for the common case the socket has been bound already. The race is resolved in inet_autobind() by reading again inet_num under the socket lock.
syzbot reported: BUG: KCSAN: data-race in inet_send_prepare / udp_lib_get_port
write to 0xffff88812cba150e of 2 bytes by task 24135 on cpu 0: udp_lib_get_port+0x4b2/0xe20 net/ipv4/udp.c:308 udp_v6_get_port+0x5e/0x70 net/ipv6/udp.c:89 inet_autobind net/ipv4/af_inet.c:183 [inline] inet_send_prepare+0xd0/0x210 net/ipv4/af_inet.c:807 inet6_sendmsg+0x29/0x80 net/ipv6/af_inet6.c:639 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_sendmmsg+0x315/0x4b0 net/socket.c:2490 __do_sys_sendmmsg net/socket.c:2519 [inline] __se_sys_sendmmsg net/socket.c:2516 [inline] __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2516 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae
read to 0xffff88812cba150e of 2 bytes by task 24132 on cpu 1: inet_send_prepare+0x21/0x210 net/ipv4/af_inet.c:806 inet6_sendmsg+0x29/0x80 net/ipv6/af_inet6.c:639 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_sendmmsg+0x315/0x4b0 net/socket.c:2490 __do_sys_sendmmsg net/socket.c:2519 [inline] __se_sys_sendmmsg net/socket.c:2516 [inline] __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2516 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae
value changed: 0x0000 -> 0x9db4
Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 24132 Comm: syz-executor.2 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 Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Chen Jun chenjun102@huawei.com Acked-by: Weilong Chen chenweilong@huawei.com Signed-off-by: Chen Jun chenjun102@huawei.com --- net/ipv4/af_inet.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index b7260c8cef2e..8267349afe23 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -572,7 +572,7 @@ int inet_dgram_connect(struct socket *sock, struct sockaddr *uaddr, return err; }
- if (!inet_sk(sk)->inet_num && inet_autobind(sk)) + if (data_race(!inet_sk(sk)->inet_num) && inet_autobind(sk)) return -EAGAIN; return sk->sk_prot->connect(sk, uaddr, addr_len); } @@ -799,7 +799,7 @@ int inet_send_prepare(struct sock *sk) sock_rps_record_flow(sk);
/* We may need to bind the socket. */ - if (!inet_sk(sk)->inet_num && !sk->sk_prot->no_autobind && + if (data_race(!inet_sk(sk)->inet_num) && !sk->sk_prot->no_autobind && inet_autobind(sk)) return -EAGAIN;