kernel/net/ipv4/udp_bpf.c, branch linux-6.2.y

bpf, sockmap: Fix an infinite loop error when len is 0 in tcp_bpf_recvmsg_parser()

2023-03-17T07:57:54Z

[ Upstream commit d900f3d20cc3169ce42ec72acc850e662a4d4db2 ] When the buffer length of the recvmsg system call is 0, we got the flollowing soft lockup problem: watchdog: BUG: soft lockup - CPU#3 stuck for 27s! [a.out:6149] CPU: 3 PID: 6149 Comm: a.out Kdump: loaded Not tainted 6.2.0+ #30 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 RIP: 0010:remove_wait_queue+0xb/0xc0 Code: 5e 41 5f c3 cc cc cc cc 0f 1f 80 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 41 57 <41> 56 41 55 41 54 55 48 89 fd 53 48 89 f3 4c 8d 6b 18 4c 8d 73 20 RSP: 0018:ffff88811b5978b8 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffff88811a7d3780 RCX: ffffffffb7a4d768 RDX: dffffc0000000000 RSI: ffff88811b597908 RDI: ffff888115408040 RBP: 1ffff110236b2f1b R08: 0000000000000000 R09: ffff88811a7d37e7 R10: ffffed10234fa6fc R11: 0000000000000001 R12: ffff88811179b800 R13: 0000000000000001 R14: ffff88811a7d38a8 R15: ffff88811a7d37e0 FS: 00007f6fb5398740(0000) GS:ffff888237180000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000000 CR3: 000000010b6ba002 CR4: 0000000000370ee0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: tcp_msg_wait_data+0x279/0x2f0 tcp_bpf_recvmsg_parser+0x3c6/0x490 inet_recvmsg+0x280/0x290 sock_recvmsg+0xfc/0x120 ____sys_recvmsg+0x160/0x3d0 ___sys_recvmsg+0xf0/0x180 __sys_recvmsg+0xea/0x1a0 do_syscall_64+0x3f/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc The logic in tcp_bpf_recvmsg_parser is as follows: msg_bytes_ready: copied = sk_msg_recvmsg(sk, psock, msg, len, flags); if (!copied) { wait data; goto msg_bytes_ready; } In this case, "copied" always is 0, the infinite loop occurs. According to the Linux system call man page, 0 should be returned in this case. Therefore, in tcp_bpf_recvmsg_parser(), if the length is 0, directly return. Also modify several other functions with the same problem. Fixes: 1f5be6b3b063 ("udp: Implement udp_bpf_recvmsg() for sockmap") Fixes: 9825d866ce0d ("af_unix: Implement unix_dgram_bpf_recvmsg()") Fixes: c5d2177a72a1 ("bpf, sockmap: Fix race in ingress receive verdict with redirect to self") Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Liu Jian Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Cc: Jakub Sitnicki Link: https://lore.kernel.org/bpf/20230303080946.1146638-1-liujian56@huawei.com Signed-off-by: Sasha Levin

net: remove SOCK_SUPPORT_ZC from sockmap

2022-10-29T03:21:25Z

sockmap replaces ->sk_prot with its own callbacks, we should remove SOCK_SUPPORT_ZC as the new proto doesn't support msghdr::ubuf_info. Cc: # 6.0 Reported-by: Jakub Kicinski Fixes: e993ffe3da4bc ("net: flag sockets supporting msghdr originated zerocopy") Signed-off-by: Pavel Begunkov Signed-off-by: Jakub Kicinski

net: remove noblock parameter from recvmsg() entities

2022-04-12T13:00:25Z

The internal recvmsg() functions have two parameters 'flags' and 'noblock' that were merged inside skb_recv_datagram(). As a follow up patch to commit f4b41f062c42 ("net: remove noblock parameter from skb_recv_datagram()") this patch removes the separate 'noblock' parameter for recvmsg(). Analogue to the referenced patch for skb_recv_datagram() the 'flags' and 'noblock' parameters are unnecessarily split up with e.g. err = sk->sk_prot->recvmsg(sk, msg, size, flags & MSG_DONTWAIT, flags & ~MSG_DONTWAIT, &addr_len); or in err = INDIRECT_CALL_2(sk->sk_prot->recvmsg, tcp_recvmsg, udp_recvmsg, sk, msg, size, flags & MSG_DONTWAIT, flags & ~MSG_DONTWAIT, &addr_len); instead of simply using only flags all the time and check for MSG_DONTWAIT where needed (to preserve for the formerly separated no(n)block condition). Signed-off-by: Oliver Hartkopp Link: https://lore.kernel.org/r/20220411124955.154876-1-socketcan@hartkopp.net Signed-off-by: Paolo Abeni

net: Implement ->sock_is_readable() for UDP and AF_UNIX

2021-10-26T19:29:33Z

Yucong noticed we can't poll() sockets in sockmap even when they are the destination sockets of redirections. This is because we never poll any psock queues in ->poll(), except for TCP. With ->sock_is_readable() now we can overwrite >sock_is_readable(), invoke and implement it for both UDP and AF_UNIX sockets. Reported-by: Yucong Sun Signed-off-by: Cong Wang Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20211008203306.37525-4-xiyou.wangcong@gmail.com

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2021-07-23T15:13:06Z

Conflicts are simple overlapping changes. Signed-off-by: David S. Miller

sock_map: Lift socket state restriction for datagram sockets

2021-07-16T01:17:49Z

TCP and other connection oriented sockets have accept() for each incoming connection on the server side, hence they can just insert those fd's from accept() to sockmap, which are of course established. Now with datagram sockets begin to support sockmap and redirection, the restriction is no longer applicable to them, as they have no accept(). So we have to lift this restriction for them. This is fine, because inside bpf_sk_redirect_map() we still have another socket status check, sock_map_redirect_allowed(), as a guard. This also means they do not have to be removed from sockmap when disconnecting. Signed-off-by: Cong Wang Signed-off-by: Alexei Starovoitov Link: https://lore.kernel.org/bpf/20210704190252.11866-3-xiyou.wangcong@gmail.com

bpf, sockmap, udp: sk_prot needs inuse_idx set for proc stats

2021-07-15T17:54:36Z

The proc socket stats use sk_prot->inuse_idx value to record inuse sock stats. We currently do not set this correctly from sockmap side. The result is reading sock stats '/proc/net/sockstat' gives incorrect values. The socket counter is incremented correctly, but because we don't set the counter correctly when we replace sk_prot we may omit the decrement. To get the correct inuse_idx value move the core_initcall that initializes the UDP proto handlers to late_initcall. This way it is initialized after UDP has the chance to assign the inuse_idx value from the register protocol handler. Fixes: edc6741cc660 ("bpf: Add sockmap hooks for UDP sockets") Signed-off-by: Jakub Sitnicki Signed-off-by: Daniel Borkmann Reviewed-by: Cong Wang Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20210714154750.528206-1-jakub@cloudflare.com

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2021-06-29T22:45:27Z

Trivial conflict in net/netfilter/nf_tables_api.c. Duplicate fix in tools/testing/selftests/net/devlink_port_split.py - take the net-next version. skmsg, and L4 bpf - keep the bpf code but remove the flags and err params. Signed-off-by: Jakub Kicinski

skmsg: Improve udp_bpf_recvmsg() accuracy

2021-06-21T14:48:11Z

I tried to reuse sk_msg_wait_data() for different protocols, but it turns out it can not be simply reused. For example, UDP actually uses two queues to receive skb: udp_sk(sk)->reader_queue and sk->sk_receive_queue. So we have to check both of them to know whether we have received any packet. Also, UDP does not lock the sock during BH Rx path, it makes no sense for its ->recvmsg() to lock the sock. It is always possible for ->recvmsg() to be called before packets actually arrive in the receive queue, we just use best effort to make it accurate here. Fixes: 1f5be6b3b063 ("udp: Implement udp_bpf_recvmsg() for sockmap") Signed-off-by: Cong Wang Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Jakub Sitnicki Link: https://lore.kernel.org/bpf/20210615021342.7416-2-xiyou.wangcong@gmail.com

skmsg: Remove unused parameters of sk_msg_wait_data()

2021-05-18T14:44:19Z

'err' and 'flags' are not used, we can just get rid of them. Signed-off-by: Cong Wang Signed-off-by: Daniel Borkmann Acked-by: Song Liu Acked-by: John Fastabend Link: https://lore.kernel.org/bpf/20210517022348.50555-1-xiyou.wangcong@gmail.com