kernel.git/net/smc, branch linux-5.10.y

net/smc: fix mismatch between CLC header and proposal

2025-12-06T21:08:17Z

[ Upstream commit ec33f2e5a2d0dbbfd71435209aee812fdc9369b8 ] The current CLC proposal message construction uses a mix of `ini->smc_type_v1/v2` and `pclc_base->hdr.typev1/v2` to decide whether to include optional extensions (IPv6 prefix extension for v1, and v2 extension). This leads to a critical inconsistency: when `smc_clc_prfx_set()` fails - for example, in IPv6-only environments with only link-local addresses, or when the local IP address and the outgoing interface’s network address are not in the same subnet. As a result, the proposal message is assembled using the stale `ini->smc_type_v1` value—causing the IPv6 prefix extension to be included even though the header indicates v1 is not supported. The peer then receives a malformed CLC proposal where the header type does not match the payload, and immediately resets the connection. The fix ensures consistency between the CLC header flags and the actual payload by synchronizing `ini->smc_type_v1` with `pclc_base->hdr.typev1` when prefix setup fails. Fixes: 8c3dca341aea ("net/smc: build and send V2 CLC proposal") Signed-off-by: D. Wythe Reviewed-by: Alexandra Winter Link: https://patch.msgid.link/20251107024029.88753-1-alibuda@linux.alibaba.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net/smc: fix data error when recvmsg with MSG_PEEK flag

2025-03-13T11:46:48Z

[ Upstream commit a4b6539038c1aa1ae871aacf6e41b566c3613993 ] When recvmsg with MSG_PEEK flag, the data will be copied to user's buffer without advancing consume cursor and without reducing the length of rx available data. Once the expected peek length is larger than the value of bytes_to_rcv, in the loop of do while in smc_rx_recvmsg, the first loop will copy bytes_to_rcv bytes of data from the position local_tx_ctrl.cons, the second loop will copy the min(bytes_to_rcv, read_remaining) bytes from the position local_tx_ctrl.cons again because of the lacking of process with advancing consume cursor and reducing the length of available data. So do the subsequent loops. The data copied in the second loop and the subsequent loops will result in data error, as it should not be copied if no more data arrives and it should be copied from the position advancing bytes_to_rcv bytes from the local_tx_ctrl.cons if more data arrives. This issue can be reproduce by the following python script: server.py: import socket import time server_ip = '0.0.0.0' server_port = 12346 server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) server_socket.bind((server_ip, server_port)) server_socket.listen(1) print('Server is running and listening for connections...') conn, addr = server_socket.accept() print('Connected by', addr) while True: data = conn.recv(1024) if not data: break print('Received request:', data.decode()) conn.sendall(b'Hello, client!\n') time.sleep(5) conn.sendall(b'Hello, again!\n') conn.close() client.py: import socket server_ip = '' server_port = 12346 resp=b'Hello, client!\nHello, again!\n' client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) client_socket.connect((server_ip, server_port)) request = 'Hello, server!' client_socket.sendall(request.encode()) peek_data = client_socket.recv(len(resp), socket.MSG_PEEK | socket.MSG_WAITALL) print('Peeked data:', peek_data.decode()) client_socket.close() Fixes: 952310ccf2d8 ("smc: receive data from RMBE") Reported-by: D. Wythe Signed-off-by: Guangguan Wang Link: https://patch.msgid.link/20250104143201.35529-1-guangguan.wang@linux.alibaba.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net/smc: check return value of sock_recvmsg when draining clc data

2025-01-09T12:24:52Z

[ Upstream commit c5b8ee5022a19464783058dc6042e8eefa34e8cd ] When receiving clc msg, the field length in smc_clc_msg_hdr indicates the length of msg should be received from network and the value should not be fully trusted as it is from the network. Once the value of length exceeds the value of buflen in function smc_clc_wait_msg it may run into deadloop when trying to drain the remaining data exceeding buflen. This patch checks the return value of sock_recvmsg when draining data in case of deadloop in draining. Fixes: fb4f79264c0f ("net/smc: tolerate future SMCD versions") Signed-off-by: Guangguan Wang Reviewed-by: Wen Gu Reviewed-by: D. Wythe Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net/smc: check iparea_offset and ipv6_prefixes_cnt when receiving proposal msg

2025-01-09T12:24:52Z

[ Upstream commit a29e220d3c8edbf0e1beb0f028878a4a85966556 ] When receiving proposal msg in server, the field iparea_offset and the field ipv6_prefixes_cnt in proposal msg are from the remote client and can not be fully trusted. Especially the field iparea_offset, once exceed the max value, there has the chance to access wrong address, and crash may happen. This patch checks iparea_offset and ipv6_prefixes_cnt before using them. Fixes: e7b7a64a8493 ("smc: support variable CLC proposal messages") Signed-off-by: Guangguan Wang Reviewed-by: Wen Gu Reviewed-by: D. Wythe Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net/smc: check sndbuf_space again after NOSPACE flag is set in smc_poll

2025-01-09T12:24:51Z

[ Upstream commit 679e9ddcf90dbdf98aaaa71a492454654b627bcb ] When application sending data more than sndbuf_space, there have chances application will sleep in epoll_wait, and will never be wakeup again. This is caused by a race between smc_poll and smc_cdc_tx_handler. application tasklet smc_tx_sendmsg(len > sndbuf_space) | epoll_wait for EPOLL_OUT,timeout=0 | smc_poll | if (!smc->conn.sndbuf_space) | | smc_cdc_tx_handler | atomic_add sndbuf_space | smc_tx_sndbuf_nonfull | if (!test_bit SOCK_NOSPACE) | do not sk_write_space; set_bit SOCK_NOSPACE; | return mask=0; | Application will sleep in epoll_wait as smc_poll returns 0. And smc_cdc_tx_handler will not call sk_write_space because the SOCK_NOSPACE has not be set. If there is no inflight cdc msg, sk_write_space will not be called any more, and application will sleep in epoll_wait forever. So check sndbuf_space again after NOSPACE flag is set to break the race. Fixes: 8dce2786a290 ("net/smc: smc_poll improvements") Signed-off-by: Guangguan Wang Suggested-by: Paolo Abeni Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net/smc: Fix searching in list of known pnetids in smc_pnet_add_pnetid

2024-11-08T15:21:57Z

[ Upstream commit 82ac39ebd6db0c9f7a97a934bda1e3e101a9d201 ] pnetid of pi (not newly allocated pe) should be compared Fixes: e888a2e8337c ("net/smc: introduce list of pnetids for Ethernet devices") Reviewed-by: D. Wythe Reviewed-by: Wen Gu Signed-off-by: Li RongQing Reviewed-by: Simon Horman Reviewed-by: Gerd Bayer Link: https://patch.msgid.link/20241014115321.33234-1-lirongqing@baidu.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net/smc: set rmb's SG_MAX_SINGLE_ALLOC limitation only when CONFIG_ARCH_NO_SG_CHAIN is defined

2024-08-19T03:40:44Z

[ Upstream commit 3ac14b9dfbd345e891d48d89f6c2fa519848f0f4 ] SG_MAX_SINGLE_ALLOC is used to limit maximum number of entries that will be allocated in one piece of scatterlist. When the entries of scatterlist exceeds SG_MAX_SINGLE_ALLOC, sg chain will be used. From commit 7c703e54cc71 ("arch: switch the default on ARCH_HAS_SG_CHAIN"), we can know that the macro CONFIG_ARCH_NO_SG_CHAIN is used to identify whether sg chain is supported. So, SMC-R's rmb buffer should be limited by SG_MAX_SINGLE_ALLOC only when the macro CONFIG_ARCH_NO_SG_CHAIN is defined. Fixes: a3fe3d01bd0d ("net/smc: introduce sg-logic for RMBs") Signed-off-by: Guangguan Wang Co-developed-by: Wen Gu Signed-off-by: Wen Gu Signed-off-by: David S. Miller Signed-off-by: Sasha Levin

net/smc: Allow SMC-D 1MB DMB allocations

2024-08-19T03:40:44Z

[ Upstream commit 67161779a9ea926fccee8de047ae66cbd3482b91 ] Commit a3fe3d01bd0d7 ("net/smc: introduce sg-logic for RMBs") introduced a restriction for RMB allocations as used by SMC-R. However, SMC-D does not use scatter-gather lists to back its DMBs, yet it was limited by this restriction, still. This patch exempts SMC, but limits allocations to the maximum RMB/DMB size respectively. Signed-off-by: Stefan Raspl Signed-off-by: Guvenc Gulce Signed-off-by: David S. Miller Stable-dep-of: 3ac14b9dfbd3 ("net/smc: set rmb's SG_MAX_SINGLE_ALLOC limitation only when CONFIG_ARCH_NO_SG_CHAIN is defined") Signed-off-by: Sasha Levin

net/smc: reduce rtnl pressure in smc_pnet_create_pnetids_list()

2024-04-13T10:59:43Z

[ Upstream commit 00af2aa93b76b1bade471ad0d0525d4d29ca5cc0 ] Many syzbot reports show extreme rtnl pressure, and many of them hint that smc acquires rtnl in netns creation for no good reason [1] This patch returns early from smc_pnet_net_init() if there is no netdevice yet. I am not even sure why smc_pnet_create_pnetids_list() even exists, because smc_pnet_netdev_event() is also calling smc_pnet_add_base_pnetid() when handling NETDEV_UP event. [1] extract of typical syzbot reports 2 locks held by syz-executor.3/12252: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.4/12253: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.1/12257: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.2/12261: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.0/12265: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.3/12268: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.4/12271: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.1/12274: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 2 locks held by syz-executor.2/12280: #0: ffffffff8f369610 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4c7/0x7b0 net/core/net_namespace.c:491 #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8f375b88 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x10a/0x1e0 net/smc/smc_pnet.c:878 Signed-off-by: Eric Dumazet Cc: Wenjia Zhang Cc: Jan Karcher Cc: "D. Wythe" Cc: Tony Lu Cc: Wen Gu Reviewed-by: Wenjia Zhang Link: https://lore.kernel.org/r/20240302100744.3868021-1-edumazet@google.com Signed-off-by: Paolo Abeni Signed-off-by: Sasha Levin

net/smc: fix illegal rmb_desc access in SMC-D connection dump

2024-02-23T07:41:55Z

[ Upstream commit dbc153fd3c142909e564bb256da087e13fbf239c ] A crash was found when dumping SMC-D connections. It can be reproduced by following steps: - run nginx/wrk test: smc_run nginx smc_run wrk -t 16 -c 1000 -d -H 'Connection: Close' - continuously dump SMC-D connections in parallel: watch -n 1 'smcss -D' BUG: kernel NULL pointer dereference, address: 0000000000000030 CPU: 2 PID: 7204 Comm: smcss Kdump: loaded Tainted: G E 6.7.0+ #55 RIP: 0010:__smc_diag_dump.constprop.0+0x5e5/0x620 [smc_diag] Call Trace: ? __die+0x24/0x70 ? page_fault_oops+0x66/0x150 ? exc_page_fault+0x69/0x140 ? asm_exc_page_fault+0x26/0x30 ? __smc_diag_dump.constprop.0+0x5e5/0x620 [smc_diag] ? __kmalloc_node_track_caller+0x35d/0x430 ? __alloc_skb+0x77/0x170 smc_diag_dump_proto+0xd0/0xf0 [smc_diag] smc_diag_dump+0x26/0x60 [smc_diag] netlink_dump+0x19f/0x320 __netlink_dump_start+0x1dc/0x300 smc_diag_handler_dump+0x6a/0x80 [smc_diag] ? __pfx_smc_diag_dump+0x10/0x10 [smc_diag] sock_diag_rcv_msg+0x121/0x140 ? __pfx_sock_diag_rcv_msg+0x10/0x10 netlink_rcv_skb+0x5a/0x110 sock_diag_rcv+0x28/0x40 netlink_unicast+0x22a/0x330 netlink_sendmsg+0x1f8/0x420 __sock_sendmsg+0xb0/0xc0 ____sys_sendmsg+0x24e/0x300 ? copy_msghdr_from_user+0x62/0x80 ___sys_sendmsg+0x7c/0xd0 ? __do_fault+0x34/0x160 ? do_read_fault+0x5f/0x100 ? do_fault+0xb0/0x110 ? __handle_mm_fault+0x2b0/0x6c0 __sys_sendmsg+0x4d/0x80 do_syscall_64+0x69/0x180 entry_SYSCALL_64_after_hwframe+0x6e/0x76 It is possible that the connection is in process of being established when we dump it. Assumed that the connection has been registered in a link group by smc_conn_create() but the rmb_desc has not yet been initialized by smc_buf_create(), thus causing the illegal access to conn->rmb_desc. So fix it by checking before dump. Fixes: 4b1b7d3b30a6 ("net/smc: add SMC-D diag support") Signed-off-by: Wen Gu Reviewed-by: Dust Li Reviewed-by: Wenjia Zhang Signed-off-by: David S. Miller Signed-off-by: Sasha Levin