From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 62352C433E0 for ; Thu, 14 May 2020 15:12:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41699205CB for ; Thu, 14 May 2020 15:12:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="vdpdPCIQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728081AbgENPMD (ORCPT ); Thu, 14 May 2020 11:12:03 -0400 Received: from userp2130.oracle.com ([156.151.31.86]:43042 "EHLO userp2130.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727938AbgENPMC (ORCPT ); Thu, 14 May 2020 11:12:02 -0400 Received: from pps.filterd (userp2130.oracle.com [127.0.0.1]) by userp2130.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 04EF6ivL050766; Thu, 14 May 2020 15:11:57 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=from : to : cc : subject : date : message-id : in-reply-to : references; s=corp-2020-01-29; bh=6o1LUfbQCyN+UnMYkK3bYQKYatwgSp8QSo7oZ6ZUnVw=; b=vdpdPCIQEEY3gUFmYa4+NH/TqKR9YZXKHn0f21aZrOCGPsfNRACQCMgnde1+uA5FrVPw HDqursrn0OuQ2FDDK2X1sA42fMY8LwRk/XW/rnz8agH21OYwQLT2vMAd7PmJ3iHnIiTr vY7xa9scRKczicZ1r+LJlfNwzMuswUh7X6QPn/hFqElp3jP6EP69lvkERAtdxyz4i+N6 KJT3ik+GxPgvLwonVCHnLnHXmOER8cN2tZ/GmEJRPQ1Vo+Fj+db3a35ZCNlFAlHE6k2P HGiX8Tih3CczcsfrKeYz6t3tP7h54t5kYSI6o5zW7A8bgvRRRzIxSIcc8jzrehDQ1tVT Sw== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2130.oracle.com with ESMTP id 3100yg35gj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 14 May 2020 15:11:57 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 04EF8J4q134514; Thu, 14 May 2020 15:11:56 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by aserp3030.oracle.com with ESMTP id 3100ycucn4-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 14 May 2020 15:11:56 +0000 Received: from abhmp0017.oracle.com (abhmp0017.oracle.com [141.146.116.23]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 04EFBsPk006327; Thu, 14 May 2020 15:11:54 GMT Received: from ca-common-hq.us.oracle.com (/10.211.9.209) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 14 May 2020 08:11:49 -0700 From: Divya Indi To: linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, Jason Gunthorpe , Kaike Wan Cc: Gerd Rausch , =?UTF-8?q?H=C3=A5kon=20Bugge?= , Srinivas Eeda , Rama Nichanamatlu , Doug Ledford , Divya Indi Subject: [PATCH] IB/sa: Resolving use-after-free in ib_nl_send_msg. Date: Thu, 14 May 2020 08:11:24 -0700 Message-Id: <1589469084-15125-2-git-send-email-divya.indi@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1589469084-15125-1-git-send-email-divya.indi@oracle.com> References: <1589469084-15125-1-git-send-email-divya.indi@oracle.com> X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9621 signatures=668687 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 bulkscore=0 malwarescore=0 phishscore=0 adultscore=0 suspectscore=2 mlxscore=0 mlxlogscore=999 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2005140133 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9621 signatures=668687 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 lowpriorityscore=0 adultscore=0 cotscore=-2147483648 mlxscore=0 suspectscore=2 spamscore=0 impostorscore=0 mlxlogscore=999 malwarescore=0 clxscore=1015 phishscore=0 bulkscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2005140133 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This patch fixes commit - commit 3ebd2fd0d011 ("IB/sa: Put netlink request into the request list before sending")' Above commit adds the query to the request list before ib_nl_snd_msg. However, if there is a delay in sending out the request (For eg: Delay due to low memory situation) the timer to handle request timeout might kick in before the request is sent out to ibacm via netlink. ib_nl_request_timeout may release the query if it fails to send it to SA as well causing a use after free situation. Call Trace for the above race: [] ? ib_pack+0x17b/0x240 [ib_core] [] ib_sa_path_rec_get+0x181/0x200 [ib_sa] [] rdma_resolve_route+0x3c0/0x8d0 [rdma_cm] [] ? cma_bind_port+0xa0/0xa0 [rdma_cm] [] ? rds_rdma_cm_event_handler_cmn+0x850/0x850 [rds_rdma] [] rds_rdma_cm_event_handler_cmn+0x22c/0x850 [rds_rdma] [] rds_rdma_cm_event_handler+0x10/0x20 [rds_rdma] [] addr_handler+0x9e/0x140 [rdma_cm] [] process_req+0x134/0x190 [ib_addr] [] process_one_work+0x169/0x4a0 [] worker_thread+0x5b/0x560 [] ? flush_delayed_work+0x50/0x50 [] kthread+0xcb/0xf0 [] ? __schedule+0x24a/0x810 [] ? __schedule+0x24a/0x810 [] ? kthread_create_on_node+0x180/0x180 [] ret_from_fork+0x47/0x90 [] ? kthread_create_on_node+0x180/0x180 .... RIP [] send_mad+0x33d/0x5d0 [ib_sa] To resolve this issue, we introduce a new flag IB_SA_NL_QUERY_SENT. This flag Indicates if the request has been sent out to ibacm yet. If this flag is not set for a query and the query times out, we add it back to the list with the original delay. To handle the case where a response is received before we could set this flag, the response handler waits for the flag to be set before proceeding with the query. Signed-off-by: Divya Indi --- drivers/infiniband/core/sa_query.c | 53 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) diff --git a/drivers/infiniband/core/sa_query.c b/drivers/infiniband/core/sa_query.c index 30d4c12..91486e7 100644 --- a/drivers/infiniband/core/sa_query.c +++ b/drivers/infiniband/core/sa_query.c @@ -42,6 +42,7 @@ #include #include #include +#include #include #include #include @@ -59,6 +60,9 @@ #define IB_SA_LOCAL_SVC_TIMEOUT_MAX 200000 #define IB_SA_CPI_MAX_RETRY_CNT 3 #define IB_SA_CPI_RETRY_WAIT 1000 /*msecs */ + +DECLARE_WAIT_QUEUE_HEAD(wait_queue); + static int sa_local_svc_timeout_ms = IB_SA_LOCAL_SVC_TIMEOUT_DEFAULT; struct ib_sa_sm_ah { @@ -123,6 +127,12 @@ struct ib_sa_query { #define IB_SA_CANCEL 0x00000002 #define IB_SA_QUERY_OPA 0x00000004 +/* + * This bit in the SA query flags indicates whether the query + * has been sent out to ibacm via netlink + */ +#define IB_SA_NL_QUERY_SENT 3 + struct ib_sa_service_query { void (*callback)(int, struct ib_sa_service_rec *, void *); void *context; @@ -746,6 +756,11 @@ static inline int ib_sa_query_cancelled(struct ib_sa_query *query) return (query->flags & IB_SA_CANCEL); } +static inline int ib_sa_nl_query_sent(struct ib_sa_query *query) +{ + return test_bit(IB_SA_NL_QUERY_SENT, (unsigned long *)&query->flags); +} + static void ib_nl_set_path_rec_attrs(struct sk_buff *skb, struct ib_sa_query *query) { @@ -889,6 +904,15 @@ static int ib_nl_make_request(struct ib_sa_query *query, gfp_t gfp_mask) spin_lock_irqsave(&ib_nl_request_lock, flags); list_del(&query->list); spin_unlock_irqrestore(&ib_nl_request_lock, flags); + } else { + set_bit(IB_SA_NL_QUERY_SENT, (unsigned long *)&query->flags); + + /* + * If response is received before this flag was set + * someone is waiting to process the response and release the + * query. + */ + wake_up(&wait_queue); } return ret; @@ -994,6 +1018,21 @@ static void ib_nl_request_timeout(struct work_struct *work) } list_del(&query->list); + + /* + * If IB_SA_NL_QUERY_SENT is not set, this query has not been + * sent to ibacm yet. Reset the timer. + */ + if (!ib_sa_nl_query_sent(query)) { + delay = msecs_to_jiffies(sa_local_svc_timeout_ms); + query->timeout = delay + jiffies; + list_add_tail(&query->list, &ib_nl_request_list); + /* Start the timeout if this is the only request */ + if (ib_nl_request_list.next == &query->list) + queue_delayed_work(ib_nl_wq, &ib_nl_timed_work, + delay); + break; + } ib_sa_disable_local_svc(query); /* Hold the lock to protect against query cancellation */ if (ib_sa_query_cancelled(query)) @@ -1122,6 +1161,20 @@ int ib_nl_handle_resolve_resp(struct sk_buff *skb, } send_buf = query->mad_buf; + /* + * In case of a quick response ie when a response comes in before + * setting IB_SA_NL_QUERY_SENT, we can have an unlikely race where the + * response handler will release the query, but we can still access the + * freed query while setting the flag. + * Hence, before proceeding and eventually releasing the query - + * wait till the flag is set. The flag should be set soon since getting + * a response is indicative of having successfully sent the query. + */ + if (unlikely(!ib_sa_nl_query_sent(query))) { + spin_unlock_irqrestore(&ib_nl_request_lock, flags); + wait_event(wait_queue, ib_sa_nl_query_sent(query)); + spin_lock_irqsave(&ib_nl_request_lock, flags); + } if (!ib_nl_is_good_resolve_resp(nlh)) { /* if the result is a failure, send out the packet via IB */ -- 1.8.3.1