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mirror of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git synced 2025-09-04 20:19:47 +08:00
linux/net/smc
D. Wythe d9cef55ed4 net/smc: fix UAF on smcsk after smc_listen_out()
BPF CI testing report a UAF issue:

  [   16.446633] BUG: kernel NULL pointer dereference, address: 000000000000003  0
  [   16.447134] #PF: supervisor read access in kernel mod  e
  [   16.447516] #PF: error_code(0x0000) - not-present pag  e
  [   16.447878] PGD 0 P4D   0
  [   16.448063] Oops: Oops: 0000 [#1] PREEMPT SMP NOPT  I
  [   16.448409] CPU: 0 UID: 0 PID: 9 Comm: kworker/0:1 Tainted: G           OE      6.13.0-rc3-g89e8a75fda73-dirty #4  2
  [   16.449124] Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODUL  E
  [   16.449502] Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/201  4
  [   16.450201] Workqueue: smc_hs_wq smc_listen_wor  k
  [   16.450531] RIP: 0010:smc_listen_work+0xc02/0x159  0
  [   16.452158] RSP: 0018:ffffb5ab40053d98 EFLAGS: 0001024  6
  [   16.452526] RAX: 0000000000000001 RBX: 0000000000000002 RCX: 000000000000030  0
  [   16.452994] RDX: 0000000000000280 RSI: 00003513840053f0 RDI: 000000000000000  0
  [   16.453492] RBP: ffffa097808e3800 R08: ffffa09782dba1e0 R09: 000000000000000  5
  [   16.453987] R10: 0000000000000000 R11: 0000000000000000 R12: ffffa0978274640  0
  [   16.454497] R13: 0000000000000000 R14: 0000000000000000 R15: ffffa09782d4092  0
  [   16.454996] FS:  0000000000000000(0000) GS:ffffa097bbc00000(0000) knlGS:000000000000000  0
  [   16.455557] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003  3
  [   16.455961] CR2: 0000000000000030 CR3: 0000000102788004 CR4: 0000000000770ef  0
  [   16.456459] PKRU: 5555555  4
  [   16.456654] Call Trace  :
  [   16.456832]  <TASK  >
  [   16.456989]  ? __die+0x23/0x7  0
  [   16.457215]  ? page_fault_oops+0x180/0x4c  0
  [   16.457508]  ? __lock_acquire+0x3e6/0x249  0
  [   16.457801]  ? exc_page_fault+0x68/0x20  0
  [   16.458080]  ? asm_exc_page_fault+0x26/0x3  0
  [   16.458389]  ? smc_listen_work+0xc02/0x159  0
  [   16.458689]  ? smc_listen_work+0xc02/0x159  0
  [   16.458987]  ? lock_is_held_type+0x8f/0x10  0
  [   16.459284]  process_one_work+0x1ea/0x6d  0
  [   16.459570]  worker_thread+0x1c3/0x38  0
  [   16.459839]  ? __pfx_worker_thread+0x10/0x1  0
  [   16.460144]  kthread+0xe0/0x11  0
  [   16.460372]  ? __pfx_kthread+0x10/0x1  0
  [   16.460640]  ret_from_fork+0x31/0x5  0
  [   16.460896]  ? __pfx_kthread+0x10/0x1  0
  [   16.461166]  ret_from_fork_asm+0x1a/0x3  0
  [   16.461453]  </TASK  >
  [   16.461616] Modules linked in: bpf_testmod(OE) [last unloaded: bpf_testmod(OE)  ]
  [   16.462134] CR2: 000000000000003  0
  [   16.462380] ---[ end trace 0000000000000000 ]---
  [   16.462710] RIP: 0010:smc_listen_work+0xc02/0x1590

The direct cause of this issue is that after smc_listen_out_connected(),
newclcsock->sk may be NULL since it will releases the smcsk. Therefore,
if the application closes the socket immediately after accept,
newclcsock->sk can be NULL. A possible execution order could be as
follows:

smc_listen_work                                 | userspace
-----------------------------------------------------------------
lock_sock(sk)                                   |
smc_listen_out_connected()                      |
| \- smc_listen_out                             |
|    | \- release_sock                          |
     | |- sk->sk_data_ready()                   |
                                                | fd = accept();
                                                | close(fd);
                                                |  \- socket->sk = NULL;
/* newclcsock->sk is NULL now */
SMC_STAT_SERV_SUCC_INC(sock_net(newclcsock->sk))

Since smc_listen_out_connected() will not fail, simply swapping the order
of the code can easily fix this issue.

Fixes: 3b2dec2603 ("net/smc: restructure client and server code in af_smc")
Signed-off-by: D. Wythe <alibuda@linux.alibaba.com>
Reviewed-by: Guangguan Wang <guangguan.wang@linux.alibaba.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Dust Li <dust.li@linux.alibaba.com>
Link: https://patch.msgid.link/20250818054618.41615-1-alibuda@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-08-19 18:27:16 -07:00
..
af_smc.c net/smc: fix UAF on smcsk after smc_listen_out() 2025-08-19 18:27:16 -07:00
Kconfig net/smc: introduce loopback-ism for SMC intra-OS shortcut 2024-04-30 13:24:48 +02:00
Makefile net/smc: Introduce IPPROTO_SMC 2024-06-17 13:14:09 +01:00
smc_cdc.c net/smc: adapt cursor update when sndbuf and peer DMB are merged 2024-04-30 13:24:48 +02:00
smc_cdc.h net/smc: fix kernel panic caused by race of smc_sock 2021-12-28 12:42:45 +00:00
smc_clc.c net: make sk->sk_rcvtimeo lockless 2025-06-23 17:05:12 -07:00
smc_clc.h net/smc: check smcd_v2_ext_offset when receiving proposal msg 2024-12-15 12:34:59 +00:00
smc_close.c net/smc: put sk reference if close work was canceled 2023-11-06 10:01:07 +00:00
smc_close.h net/smc: remove close abort worker 2019-10-22 11:23:44 -07:00
smc_core.c net/smc: remove unused input parameters in smc_buf_get_slot 2025-06-19 16:15:34 -07:00
smc_core.h net/smc: support SMC-R V2 for rdma devices with max_recv_sge equals to 1 2024-12-12 13:50:00 +01:00
smc_diag.c net: remove sock_i_uid() 2025-06-23 17:04:03 -07:00
smc_ib.c net/smc: support SMC-R V2 for rdma devices with max_recv_sge equals to 1 2024-12-12 13:50:00 +01:00
smc_ib.h net/smc: fix smc clc failed issue when netdevice not in init_net 2023-10-13 16:52:02 -07:00
smc_inet.c net/smc: fix lacks of icsk_syn_mss with IPPROTO_SMC 2024-10-10 08:48:11 -07:00
smc_inet.h net/smc: Introduce IPPROTO_SMC 2024-06-17 13:14:09 +01:00
smc_ism.c net/smc: add operations to merge sndbuf with peer DMB 2024-04-30 13:24:48 +02:00
smc_ism.h net/smc: add operations to merge sndbuf with peer DMB 2024-04-30 13:24:48 +02:00
smc_llc.c net/smc: support SMC-R V2 for rdma devices with max_recv_sge equals to 1 2024-12-12 13:50:00 +01:00
smc_llc.h net/smc: Introduce a specific sysctl for TEST_LINK time 2022-09-22 12:58:21 +02:00
smc_loopback.c net/smc: remove unused function smc_lo_supports_v2 2025-06-21 08:26:42 -07:00
smc_loopback.h net/smc: remove unreferenced header in smc_loopback.h file 2024-07-31 11:48:58 +01:00
smc_netlink.c genetlink: start to validate reserved header bytes 2022-08-29 12:47:15 +01:00
smc_netlink.h net/smc: add support for user defined EIDs 2021-09-14 12:49:10 +01:00
smc_netns.h net/smc: introduce list of pnetids for Ethernet devices 2020-09-28 15:19:03 -07:00
smc_pnet.c net/smc: replace strncpy with strscpy 2025-06-23 16:56:21 -07:00
smc_pnet.h net/smc: Use a mutex for locking "struct smc_pnettable" 2022-02-24 09:09:33 -08:00
smc_rx.c net/smc: fix data error when recvmsg with MSG_PEEK flag 2025-01-13 18:59:00 -08:00
smc_rx.h net/smc: fix data error when recvmsg with MSG_PEEK flag 2025-01-13 18:59:00 -08:00
smc_stats.c net/smc: introduce statistics for ringbufs usage of net namespace 2024-08-20 11:38:23 +02:00
smc_stats.h net/smc: introduce statistics for ringbufs usage of net namespace 2024-08-20 11:38:23 +02:00
smc_sysctl.c net/smc: add sysctl for smc_limit_hs 2024-09-10 12:11:04 +02:00
smc_sysctl.h net/smc: add sysctl for max conns per lgr for SMC-R v2.1 2023-11-24 12:13:14 +00:00
smc_tracepoint.c net/smc: Introduce tracepoint for smcr link down 2021-11-01 13:39:14 +00:00
smc_tracepoint.h tracing/treewide: Remove second parameter of __assign_str() 2024-05-22 20:14:47 -04:00
smc_tx.c net/smc: remove unneeded atomic operations in smc_tx_sndbuf_nonempty 2023-11-24 15:00:47 +00:00
smc_tx.h smc: Drop smc_sendpage() in favour of smc_sendmsg() + MSG_SPLICE_PAGES 2023-06-24 15:50:12 -07:00
smc_wr.c net/smc: support SMC-R V2 for rdma devices with max_recv_sge equals to 1 2024-12-12 13:50:00 +01:00
smc_wr.h net/smc: Use percpu ref for wr tx reference 2023-03-17 08:59:01 +00:00
smc.h smc: Fix various oops due to inet_sock type confusion. 2025-07-14 17:12:42 -07:00