| From 18a419bad63b7f68a1979e28459782518e7b6bbe Mon Sep 17 00:00:00 2001 |
| From: Eric Dumazet <edumazet@google.com> |
| Date: Wed, 30 Jun 2021 09:42:44 -0700 |
| Subject: udp: annotate data races around unix_sk(sk)->gso_size |
| |
| From: Eric Dumazet <edumazet@google.com> |
| |
| commit 18a419bad63b7f68a1979e28459782518e7b6bbe upstream. |
| |
| Accesses to unix_sk(sk)->gso_size are lockless. |
| Add READ_ONCE()/WRITE_ONCE() around them. |
| |
| BUG: KCSAN: data-race in udp_lib_setsockopt / udpv6_sendmsg |
| |
| write to 0xffff88812d78f47c of 2 bytes by task 10849 on cpu 1: |
| udp_lib_setsockopt+0x3b3/0x710 net/ipv4/udp.c:2696 |
| udpv6_setsockopt+0x63/0x90 net/ipv6/udp.c:1630 |
| sock_common_setsockopt+0x5d/0x70 net/core/sock.c:3265 |
| __sys_setsockopt+0x18f/0x200 net/socket.c:2104 |
| __do_sys_setsockopt net/socket.c:2115 [inline] |
| __se_sys_setsockopt net/socket.c:2112 [inline] |
| __x64_sys_setsockopt+0x62/0x70 net/socket.c:2112 |
| do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 |
| entry_SYSCALL_64_after_hwframe+0x44/0xae |
| |
| read to 0xffff88812d78f47c of 2 bytes by task 10852 on cpu 0: |
| udpv6_sendmsg+0x161/0x16b0 net/ipv6/udp.c:1299 |
| inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:642 |
| sock_sendmsg_nosec net/socket.c:654 [inline] |
| sock_sendmsg net/socket.c:674 [inline] |
| ____sys_sendmsg+0x360/0x4d0 net/socket.c:2337 |
| ___sys_sendmsg net/socket.c:2391 [inline] |
| __sys_sendmmsg+0x315/0x4b0 net/socket.c:2477 |
| __do_sys_sendmmsg net/socket.c:2506 [inline] |
| __se_sys_sendmmsg net/socket.c:2503 [inline] |
| __x64_sys_sendmmsg+0x53/0x60 net/socket.c:2503 |
| do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 |
| entry_SYSCALL_64_after_hwframe+0x44/0xae |
| |
| value changed: 0x0000 -> 0x0005 |
| |
| Reported by Kernel Concurrency Sanitizer on: |
| CPU: 0 PID: 10852 Comm: syz-executor.0 Not tainted 5.13.0-syzkaller #0 |
| Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 |
| |
| Fixes: bec1f6f69736 ("udp: generate gso with UDP_SEGMENT") |
| Signed-off-by: Eric Dumazet <edumazet@google.com> |
| Cc: Willem de Bruijn <willemb@google.com> |
| Reported-by: syzbot <syzkaller@googlegroups.com> |
| Signed-off-by: David S. Miller <davem@davemloft.net> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| --- |
| net/ipv4/udp.c | 6 +++--- |
| net/ipv6/udp.c | 2 +- |
| 2 files changed, 4 insertions(+), 4 deletions(-) |
| |
| --- a/net/ipv4/udp.c |
| +++ b/net/ipv4/udp.c |
| @@ -1097,7 +1097,7 @@ int udp_sendmsg(struct sock *sk, struct |
| } |
| |
| ipcm_init_sk(&ipc, inet); |
| - ipc.gso_size = up->gso_size; |
| + ipc.gso_size = READ_ONCE(up->gso_size); |
| |
| if (msg->msg_controllen) { |
| err = udp_cmsg_send(sk, msg, &ipc.gso_size); |
| @@ -2655,7 +2655,7 @@ int udp_lib_setsockopt(struct sock *sk, |
| case UDP_SEGMENT: |
| if (val < 0 || val > USHRT_MAX) |
| return -EINVAL; |
| - up->gso_size = val; |
| + WRITE_ONCE(up->gso_size, val); |
| break; |
| |
| case UDP_GRO: |
| @@ -2750,7 +2750,7 @@ int udp_lib_getsockopt(struct sock *sk, |
| break; |
| |
| case UDP_SEGMENT: |
| - val = up->gso_size; |
| + val = READ_ONCE(up->gso_size); |
| break; |
| |
| case UDP_GRO: |
| --- a/net/ipv6/udp.c |
| +++ b/net/ipv6/udp.c |
| @@ -1294,7 +1294,7 @@ int udpv6_sendmsg(struct sock *sk, struc |
| int (*getfrag)(void *, char *, int, int, int, struct sk_buff *); |
| |
| ipcm6_init(&ipc6); |
| - ipc6.gso_size = up->gso_size; |
| + ipc6.gso_size = READ_ONCE(up->gso_size); |
| ipc6.sockc.tsflags = sk->sk_tsflags; |
| ipc6.sockc.mark = sk->sk_mark; |
| |