From patchwork Wed Aug 7 10:39:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Antipov X-Patchwork-Id: 13756138 X-Patchwork-Delegate: kuba@kernel.org Received: from forward201a.mail.yandex.net (forward201a.mail.yandex.net [178.154.239.92]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 794C81C8FBB for ; Wed, 7 Aug 2024 10:47:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.154.239.92 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723027668; cv=none; b=d36QeBqmtuk7bJ14rGo/yeJTFO0swWH48DkT9nzH8MI75ipPLh/5GOKmwRm85QbIfAqRTUC7q2NXZTw725nRTFAHI4oskaxZScPF8P7lf/Rhscw/s/dZt4vcBvRuu2ETykImudV22/VHihNBldBFLiesI06K9HnR06ToGVgQpYs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723027668; c=relaxed/simple; bh=r/xcw4mkfLvHrB7PfXQuHyAeZI0Y0vdAmcw8mBFA1B8=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=uWg520K4mkAze/2LrihMOLtJWRrM+NUPKt/3Og83FKjcFdbAAkSllPbC5yrteqNx0wCNaSxH+JdZPHPxTX9wq8Voc0eEu69j/xzEjiMzjA3pvyE92/C70WGM34ufduO6JcAQBecOBG7MKZ/P5hjXmO7K1ZQBamwo80waaEVqfoQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=yandex.ru; spf=pass smtp.mailfrom=yandex.ru; dkim=pass (1024-bit key) header.d=yandex.ru header.i=@yandex.ru header.b=ncrkBtjV; arc=none smtp.client-ip=178.154.239.92 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=yandex.ru Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=yandex.ru Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=yandex.ru header.i=@yandex.ru header.b="ncrkBtjV" Received: from forward101a.mail.yandex.net (forward101a.mail.yandex.net [IPv6:2a02:6b8:c0e:500:1:45:d181:d101]) by forward201a.mail.yandex.net (Yandex) with ESMTPS id D063D62A0C for ; Wed, 7 Aug 2024 13:40:41 +0300 (MSK) Received: from mail-nwsmtp-smtp-production-main-31.vla.yp-c.yandex.net (mail-nwsmtp-smtp-production-main-31.vla.yp-c.yandex.net [IPv6:2a02:6b8:c0f:26bf:0:640:efa0:0]) by forward101a.mail.yandex.net (Yandex) with ESMTPS id D747B60AC0; Wed, 7 Aug 2024 13:40:33 +0300 (MSK) Received: by mail-nwsmtp-smtp-production-main-31.vla.yp-c.yandex.net (smtp/Yandex) with ESMTPSA id WeaXEH6Sl4Y0-cbPFdGVk; Wed, 07 Aug 2024 13:40:33 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1723027233; bh=AF4nlcPDOOqSXjDCWCvo6NX6QZUE6FVV55e/YuwK8Nc=; h=Message-ID:Date:Cc:Subject:To:From; b=ncrkBtjVMJXCbjh+BUwlWyWRhOcWTs+lcZp1tvOZEEowqW21KoavQ8PV/eldyGLic l16MzOHM0Web8nVnGOYuS5/sSMifqHFWoRNG26T56SpcZz0JlfRSwpk/clkrJTgOS7 GUPrDC+KUdiEORtWeEBhjE49m3TC5WZxsg038FmQ= Authentication-Results: mail-nwsmtp-smtp-production-main-31.vla.yp-c.yandex.net; dkim=pass header.i=@yandex.ru From: Dmitry Antipov To: Vinicius Costa Gomes Cc: Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, lvc-project@linuxtesting.org, Dmitry Antipov , syzbot+b65e0af58423fc8a73aa@syzkaller.appspotmail.com Subject: [PATCH 1/3] net: sched: fix use-after-free in taprio_change() Date: Wed, 7 Aug 2024 13:39:41 +0300 Message-ID: <20240807103943.1633950-1-dmantipov@yandex.ru> X-Mailer: git-send-email 2.45.2 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org In 'taprio_change()', 'admin' pointer may become dangling due to sched switch / removal caused by 'advance_sched()', and critical section protected by 'q->current_entry_lock' is too small to prevent from such a scenario (which causes use-after-free detected by KASAN). Fix this by prefer 'rcu_replace_pointer()' over 'rcu_assign_pointer()' to update 'admin' immediately before an attempt to schedule freeing. Fixes: a3d43c0d56f1 ("taprio: Add support adding an admin schedule") Reported-by: syzbot+b65e0af58423fc8a73aa@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=b65e0af58423fc8a73aa Signed-off-by: Dmitry Antipov --- net/sched/sch_taprio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index cc2df9f8c14a..59fad74d5ff9 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1963,7 +1963,8 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, taprio_start_sched(sch, start, new_admin); - rcu_assign_pointer(q->admin_sched, new_admin); + admin = rcu_replace_pointer(q->admin_sched, new_admin, + lockdep_rtnl_is_held()); if (admin) call_rcu(&admin->rcu, taprio_free_sched_cb); From patchwork Wed Aug 7 10:39:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Antipov X-Patchwork-Id: 13756125 X-Patchwork-Delegate: kuba@kernel.org Received: from forward100a.mail.yandex.net (forward100a.mail.yandex.net [178.154.239.83]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CAD5D1D174E for ; Wed, 7 Aug 2024 10:40:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.154.239.83 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723027246; cv=none; b=I7ljzDvrA0O82nm2rZLzxvI8+PsuiZzj/KIDizqIPNvPU4TRu2WLPVgcDglhGcX4oSjLHvNUQ19R/r4J4PewplE2i60RqiVG6NaC6XyjlHZCAR0I0btlXkuhEdDBt3j7FJcnubqO90wQxMv0rJJT//653UXaa0+HXsy9XcPbGL8= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1723027246; c=relaxed/simple; bh=sNzghOZRnhUdLIEW9FS2CAIFsCt66cKO/7HKQd+Cl2w=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=t5p5vfwQTdjnNc86iW4HMp/5Q1/fmj35vzK+2A3XbWIHwALq7YmxWNQlSkDhXPJ8gdFt1GCvDdN1b0Bzox2N/MA3JfA0rxoKY8+MULEFRrH9LyrEOvpSH/SKILDQ+JvNU9DJ2Cx5bRwNDpXOilDyv2CzN/Hm96K4RCh07PHjNlE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=yandex.ru; spf=pass smtp.mailfrom=yandex.ru; dkim=pass (1024-bit key) header.d=yandex.ru header.i=@yandex.ru header.b=ZeF6R5L2; arc=none smtp.client-ip=178.154.239.83 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=yandex.ru Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=yandex.ru Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=yandex.ru header.i=@yandex.ru header.b="ZeF6R5L2" Received: from mail-nwsmtp-smtp-production-main-31.vla.yp-c.yandex.net (mail-nwsmtp-smtp-production-main-31.vla.yp-c.yandex.net [IPv6:2a02:6b8:c0f:26bf:0:640:efa0:0]) by forward100a.mail.yandex.net (Yandex) with ESMTPS id 72F3846D63; Wed, 7 Aug 2024 13:40:34 +0300 (MSK) Received: by mail-nwsmtp-smtp-production-main-31.vla.yp-c.yandex.net (smtp/Yandex) with ESMTPSA id WeaXEH6Sl4Y0-VvbIajb6; Wed, 07 Aug 2024 13:40:34 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1723027234; bh=gHc6pJSmw7497IEttLpPGX8BTDtpMO2MTOytUBeRWFk=; h=Message-ID:Date:In-Reply-To:Cc:Subject:References:To:From; b=ZeF6R5L2Z2fALRwOqwhle1suX6+l6cvGv8ylx0T4eWy0RkvK9hFrkQGVg6h+Fdtca F1UcJxMWtHB7RAzqUfiMpzVgmums0NCSkly4GalwdeVupyiUlg1r+RFPIJ0fjKICfp ts/XObv3XQnQCUIy9HNF0RetVznAJWgbOlABxXHM= Authentication-Results: mail-nwsmtp-smtp-production-main-31.vla.yp-c.yandex.net; dkim=pass header.i=@yandex.ru From: Dmitry Antipov To: Vinicius Costa Gomes Cc: Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, lvc-project@linuxtesting.org, Dmitry Antipov Subject: [PATCH 2/3] net: sched: consistently use rcu_replace_pointer() in taprio_change() Date: Wed, 7 Aug 2024 13:39:42 +0300 Message-ID: <20240807103943.1633950-2-dmantipov@yandex.ru> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240807103943.1633950-1-dmantipov@yandex.ru> References: <20240807103943.1633950-1-dmantipov@yandex.ru> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org According to Vinicius (and carefully looking through the whole thing once again), txtime branch of 'taprio_change()' is not going to race against 'advance_sched()'. But using 'rcu_replace_pointer()' in the former may be a good idea as well. Suggested-by: Vinicius Costa Gomes Signed-off-by: Dmitry Antipov --- net/sched/sch_taprio.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index 59fad74d5ff9..9f4e004cdb8b 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1952,7 +1952,9 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, goto unlock; } - rcu_assign_pointer(q->admin_sched, new_admin); + /* Not going to race against advance_sched(), but still */ + admin = rcu_replace_pointer(q->admin_sched, new_admin, + lockdep_rtnl_is_held()); if (admin) call_rcu(&admin->rcu, taprio_free_sched_cb); } else { From patchwork Wed Aug 7 10:39:43 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Antipov X-Patchwork-Id: 13756126 X-Patchwork-Delegate: kuba@kernel.org Received: from forward102a.mail.yandex.net (forward102a.mail.yandex.net [178.154.239.85]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id AD30E745CB for ; 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dkim=pass header.i=@yandex.ru From: Dmitry Antipov To: Vinicius Costa Gomes Cc: Jakub Kicinski , Paolo Abeni , netdev@vger.kernel.org, lvc-project@linuxtesting.org, Dmitry Antipov Subject: [PATCH 3/3] net: sched: use RCU read-side critical section in taprio_dump() Date: Wed, 7 Aug 2024 13:39:43 +0300 Message-ID: <20240807103943.1633950-3-dmantipov@yandex.ru> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240807103943.1633950-1-dmantipov@yandex.ru> References: <20240807103943.1633950-1-dmantipov@yandex.ru> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org Not sure why this is not reproducible on x86, but I occasionally see the following crash on arm64 (note that original issue was found at https://syzkaller.appspot.com/bug?extid=b65e0af58423fc8a73aa on arm64): [ 1601.079132][T15862] BUG: KASAN: slab-use-after-free in taprio_dump+0xa0c/0xbb0 [ 1601.082101][T15862] Read of size 4 at addr ffff0000d4bb88f8 by task repro/15862 [ 1601.085149][T15862] [ 1601.093445][T15862] CPU: 0 UID: 0 PID: 15862 Comm: repro Not tainted 6.11.0-rc1-00293-gdefaf1a2113a-dirty #2 [ 1601.100771][T15862] Hardware name: QEMU QEMU Virtual Machine, BIOS edk2-20240524-5.fc40 05/24/2024 [ 1601.106651][T15862] Call trace: [ 1601.107395][T15862] dump_backtrace+0x20c/0x220 [ 1601.108397][T15862] show_stack+0x2c/0x40 [ 1601.109220][T15862] dump_stack_lvl+0xf8/0x174 [ 1601.110041][T15862] print_report+0x170/0x4d8 [ 1601.110848][T15862] kasan_report+0xb8/0x1d4 [ 1601.111991][T15862] __asan_report_load4_noabort+0x20/0x2c [ 1601.112880][T15862] taprio_dump+0xa0c/0xbb0 [ 1601.113725][T15862] tc_fill_qdisc+0x540/0x1020 [ 1601.114586][T15862] qdisc_notify.isra.0+0x330/0x3a0 [ 1601.115506][T15862] tc_modify_qdisc+0x7b8/0x1838 [ 1601.116378][T15862] rtnetlink_rcv_msg+0x3c8/0xc20 [ 1601.117320][T15862] netlink_rcv_skb+0x1f8/0x3d4 [ 1601.118164][T15862] rtnetlink_rcv+0x28/0x40 [ 1601.119037][T15862] netlink_unicast+0x51c/0x790 [ 1601.119874][T15862] netlink_sendmsg+0x79c/0xc20 [ 1601.120706][T15862] __sock_sendmsg+0xe0/0x1a0 [ 1601.121802][T15862] ____sys_sendmsg+0x6c0/0x840 [ 1601.122722][T15862] ___sys_sendmsg+0x1ac/0x1f0 [ 1601.123653][T15862] __sys_sendmsg+0x110/0x1d0 [ 1601.124459][T15862] __arm64_sys_sendmsg+0x74/0xb0 [ 1601.125316][T15862] invoke_syscall+0x88/0x2e0 [ 1601.126155][T15862] el0_svc_common.constprop.0+0xe4/0x2a0 [ 1601.127051][T15862] do_el0_svc+0x44/0x60 [ 1601.127837][T15862] el0_svc+0x50/0x184 [ 1601.128639][T15862] el0t_64_sync_handler+0x120/0x12c [ 1601.129505][T15862] el0t_64_sync+0x190/0x194 [ 1601.130591][T15862] [ 1601.131361][T15862] Allocated by task 15857: [ 1601.132224][T15862] kasan_save_stack+0x3c/0x70 [ 1601.133193][T15862] kasan_save_track+0x20/0x3c [ 1601.134102][T15862] kasan_save_alloc_info+0x40/0x60 [ 1601.134955][T15862] __kasan_kmalloc+0xd4/0xe0 [ 1601.135965][T15862] __kmalloc_cache_noprof+0x194/0x334 [ 1601.136874][T15862] taprio_change+0x45c/0x2fe0 [ 1601.137859][T15862] tc_modify_qdisc+0x6a8/0x1838 [ 1601.138838][T15862] rtnetlink_rcv_msg+0x3c8/0xc20 [ 1601.139799][T15862] netlink_rcv_skb+0x1f8/0x3d4 [ 1601.140664][T15862] rtnetlink_rcv+0x28/0x40 [ 1601.141725][T15862] netlink_unicast+0x51c/0x790 [ 1601.142662][T15862] netlink_sendmsg+0x79c/0xc20 [ 1601.143523][T15862] __sock_sendmsg+0xe0/0x1a0 [ 1601.144445][T15862] ____sys_sendmsg+0x6c0/0x840 [ 1601.145467][T15862] ___sys_sendmsg+0x1ac/0x1f0 [ 1601.146410][T15862] __sys_sendmsg+0x110/0x1d0 [ 1601.147293][T15862] __arm64_sys_sendmsg+0x74/0xb0 [ 1601.148116][T15862] invoke_syscall+0x88/0x2e0 [ 1601.148912][T15862] el0_svc_common.constprop.0+0xe4/0x2a0 [ 1601.149754][T15862] do_el0_svc+0x44/0x60 [ 1601.150532][T15862] el0_svc+0x50/0x184 [ 1601.151438][T15862] el0t_64_sync_handler+0x120/0x12c [ 1601.152311][T15862] el0t_64_sync+0x190/0x194 [ 1601.153208][T15862] [ 1601.153751][T15862] Freed by task 6192: [ 1601.154491][T15862] kasan_save_stack+0x3c/0x70 [ 1601.155491][T15862] kasan_save_track+0x20/0x3c [ 1601.156521][T15862] kasan_save_free_info+0x4c/0x80 [ 1601.157357][T15862] poison_slab_object+0x110/0x160 [ 1601.158300][T15862] __kasan_slab_free+0x3c/0x74 [ 1601.159265][T15862] kfree+0x134/0x3c0 [ 1601.160068][T15862] taprio_free_sched_cb+0x18c/0x220 [ 1601.161046][T15862] rcu_core+0x920/0x1b7c [ 1601.161906][T15862] rcu_core_si+0x10/0x1c [ 1601.162693][T15862] handle_softirqs+0x2e8/0xd64 [ 1601.163518][T15862] __do_softirq+0x14/0x20 Fix this by adding RCU read-side critical section to 'taprio_dump()'. Signed-off-by: Dmitry Antipov Acked-by: Vinicius Costa Gomes --- net/sched/sch_taprio.c | 37 +++++++++++++++++++++---------------- 1 file changed, 21 insertions(+), 16 deletions(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index 9f4e004cdb8b..f31feca381c4 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -2374,9 +2374,6 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) struct tc_mqprio_qopt opt = { 0 }; struct nlattr *nest, *sched_nest; - oper = rtnl_dereference(q->oper_sched); - admin = rtnl_dereference(q->admin_sched); - mqprio_qopt_reconstruct(dev, &opt); nest = nla_nest_start_noflag(skb, TCA_OPTIONS); @@ -2397,29 +2394,37 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) nla_put_u32(skb, TCA_TAPRIO_ATTR_TXTIME_DELAY, q->txtime_delay)) goto options_error; + rcu_read_lock(); + + oper = rtnl_dereference(q->oper_sched); + admin = rtnl_dereference(q->admin_sched); + if (oper && taprio_dump_tc_entries(skb, q, oper)) - goto options_error; + goto unlock; if (oper && dump_schedule(skb, oper)) - goto options_error; + goto unlock; - if (!admin) - goto done; + if (admin) { + sched_nest = + nla_nest_start_noflag(skb, TCA_TAPRIO_ATTR_ADMIN_SCHED); + if (!sched_nest) + goto unlock; - sched_nest = nla_nest_start_noflag(skb, TCA_TAPRIO_ATTR_ADMIN_SCHED); - if (!sched_nest) - goto options_error; + if (dump_schedule(skb, admin)) { + nla_nest_cancel(skb, sched_nest); + goto unlock; + } - if (dump_schedule(skb, admin)) - goto admin_error; + nla_nest_end(skb, sched_nest); + } - nla_nest_end(skb, sched_nest); + rcu_read_unlock(); -done: return nla_nest_end(skb, nest); -admin_error: - nla_nest_cancel(skb, sched_nest); +unlock: + rcu_read_unlock(); options_error: nla_nest_cancel(skb, nest);