diff options
| author | Eric Dumazet <edumazet@google.com> | 2023-09-12 09:17:28 +0000 |
|---|---|---|
| committer | Paolo Abeni <pabeni@redhat.com> | 2023-09-14 16:16:36 +0200 |
| commit | 70a36f571362a8de8b8c02d21ae524fc776287f2 (patch) | |
| tree | abb95a603a63dab903aacd601ab78c91a388400f /net/ipv6/udp.c | |
| parent | ac9a7f4ce5dda1472e8f44096f33066c6ec1a3b4 (diff) | |
udp: annotate data-races around udp->encap_type
syzbot/KCSAN complained about UDP_ENCAP_L2TPINUDP setsockopt() racing.
Add READ_ONCE()/WRITE_ONCE() to document races on this lockless field.
syzbot report was:
BUG: KCSAN: data-race in udp_lib_setsockopt / udp_lib_setsockopt
read-write to 0xffff8881083603fa of 1 bytes by task 16557 on cpu 0:
udp_lib_setsockopt+0x682/0x6c0
udp_setsockopt+0x73/0xa0 net/ipv4/udp.c:2779
sock_common_setsockopt+0x61/0x70 net/core/sock.c:3697
__sys_setsockopt+0x1c9/0x230 net/socket.c:2263
__do_sys_setsockopt net/socket.c:2274 [inline]
__se_sys_setsockopt net/socket.c:2271 [inline]
__x64_sys_setsockopt+0x66/0x80 net/socket.c:2271
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
read-write to 0xffff8881083603fa of 1 bytes by task 16554 on cpu 1:
udp_lib_setsockopt+0x682/0x6c0
udp_setsockopt+0x73/0xa0 net/ipv4/udp.c:2779
sock_common_setsockopt+0x61/0x70 net/core/sock.c:3697
__sys_setsockopt+0x1c9/0x230 net/socket.c:2263
__do_sys_setsockopt net/socket.c:2274 [inline]
__se_sys_setsockopt net/socket.c:2271 [inline]
__x64_sys_setsockopt+0x66/0x80 net/socket.c:2271
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
value changed: 0x01 -> 0x05
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 16554 Comm: syz-executor.5 Not tainted 6.5.0-rc7-syzkaller-00004-gf7757129e3de #0
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Diffstat (limited to 'net/ipv6/udp.c')
| -rw-r--r-- | net/ipv6/udp.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c index 90688877e900..0e79d189613b 100644 --- a/net/ipv6/udp.c +++ b/net/ipv6/udp.c @@ -571,7 +571,7 @@ int __udp6_lib_err(struct sk_buff *skb, struct inet6_skb_parm *opt, sk = __udp6_lib_lookup(net, daddr, uh->dest, saddr, uh->source, inet6_iif(skb), inet6_sdif(skb), udptable, NULL); - if (!sk || udp_sk(sk)->encap_type) { + if (!sk || READ_ONCE(udp_sk(sk)->encap_type)) { /* No socket for error: try tunnels before discarding */ if (static_branch_unlikely(&udpv6_encap_needed_key)) { sk = __udp6_lib_err_encap(net, hdr, offset, uh, @@ -688,7 +688,8 @@ static int udpv6_queue_rcv_one_skb(struct sock *sk, struct sk_buff *skb) } nf_reset_ct(skb); - if (static_branch_unlikely(&udpv6_encap_needed_key) && up->encap_type) { + if (static_branch_unlikely(&udpv6_encap_needed_key) && + READ_ONCE(up->encap_type)) { int (*encap_rcv)(struct sock *sk, struct sk_buff *skb); /* |