From bfae53240c0ea782a82759ef641fc1d38eb6dee0 Mon Sep 17 00:00:00 2001 From: Wen Gu Date: Wed, 27 Dec 2023 15:40:35 +0800 Subject: [PATCH 1/2] net/smc: fix invalid link access in dumping SMC-R connections ANBZ: #8518 commit 9dbe086c69b8902c85cece394760ac212e9e4ccc upstream. A crash was found when dumping SMC-R connections. It can be reproduced by following steps: - environment: two RNICs on both sides. - run SMC-R between two sides, now a SMC_LGR_SYMMETRIC type link group will be created. - set the first RNIC down on either side and link group will turn to SMC_LGR_ASYMMETRIC_LOCAL then. - run 'smcss -R' and the crash will be triggered. BUG: kernel NULL pointer dereference, address: 0000000000000010 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 8000000101fdd067 P4D 8000000101fdd067 PUD 10ce46067 PMD 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 3 PID: 1810 Comm: smcss Kdump: loaded Tainted: G W E 6.7.0-rc6+ #51 RIP: 0010:__smc_diag_dump.constprop.0+0x36e/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+0x36e/0x620 [smc_diag] 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+0x240/0x4a0 __sock_sendmsg+0xb0/0xc0 ____sys_sendmsg+0x24e/0x300 ? copy_msghdr_from_user+0x62/0x80 ___sys_sendmsg+0x7c/0xd0 ? __do_fault+0x34/0x1a0 ? do_read_fault+0x5f/0x100 ? do_fault+0xb0/0x110 __sys_sendmsg+0x4d/0x80 do_syscall_64+0x45/0xf0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 When the first RNIC is set down, the lgr->lnk[0] will be cleared and an asymmetric link will be allocated in lgr->link[SMC_LINKS_PER_LGR_MAX - 1] by smc_llc_alloc_alt_link(). Then when we try to dump SMC-R connections in __smc_diag_dump(), the invalid lgr->lnk[0] will be accessed, resulting in this issue. So fix it by accessing the right link. Fixes: f16a7dd5cf27 ("smc: netlink interface for SMC sockets") Reported-by: henaumars Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7616 Signed-off-by: Wen Gu Reviewed-by: Tony Lu Link: https://lore.kernel.org/r/1703662835-53416-1-git-send-email-guwen@linux.alibaba.com Signed-off-by: Jakub Kicinski [Fixes conflicts] Signed-off-by: Wen Gu --- net/smc/smc_diag.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/smc/smc_diag.c b/net/smc/smc_diag.c index 55ac060acb6d..2b4a6aef15fe 100644 --- a/net/smc/smc_diag.c +++ b/net/smc/smc_diag.c @@ -172,7 +172,7 @@ static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb, }; memcpy(linfo.lnk[0].ibname, - smc->conn.lgr->lnk[0].smcibdev->ibdev->name, + smc->conn.lnk->smcibdev->ibdev->name, sizeof(smc->conn.lnk->smcibdev->ibdev->name)); smc_gid_be16_convert(linfo.lnk[0].gid, smc->conn.lnk->gid); -- Gitee From 5f63c0399aac8b7422dd0a10ba63ec4da2b55b16 Mon Sep 17 00:00:00 2001 From: Wen Gu Date: Thu, 18 Jan 2024 12:32:10 +0800 Subject: [PATCH 2/2] net/smc: fix illegal rmb_desc access in SMC-D connection dump ANBZ: #8518 commit dbc153fd3c142909e564bb256da087e13fbf239c upstream. 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: Wen Gu --- net/smc/smc_diag.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/smc/smc_diag.c b/net/smc/smc_diag.c index 2b4a6aef15fe..53bc21e31331 100644 --- a/net/smc/smc_diag.c +++ b/net/smc/smc_diag.c @@ -184,7 +184,7 @@ static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb, } if (smc_conn_lgr_valid(&smc->conn) && smc->conn.lgr->is_smcd && (req->diag_ext & (1 << (SMC_DIAG_DMBINFO - 1))) && - !list_empty(&smc->conn.lgr->list)) { + !list_empty(&smc->conn.lgr->list) && smc->conn.rmb_desc) { struct smc_connection *conn = &smc->conn; struct smcd_diag_dmbinfo dinfo; struct smcd_dev *smcd = conn->lgr->smcd; -- Gitee