From patchwork Wed Sep 4 12:08:41 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Antipov X-Patchwork-Id: 13790702 X-Patchwork-Delegate: kuba@kernel.org Received: from forward101b.mail.yandex.net (forward101b.mail.yandex.net [178.154.239.148]) (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 3941F1D88AF for ; Wed, 4 Sep 2024 12:08:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.154.239.148 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725451730; cv=none; b=ZbLOWHUMcHPDhftnAoQTP80NVH3rxaMXo3IyWZSnawzHecHS74lGsgh//Oyu9T0OfTZbpV4vh30Yv/3OjpWUaL846c4YX5M/WZKYFjrtRz3oMYxUmB24k7vQybs/jXWnhW1f9SdDLpNR5JCvBoA8oV8nj99T3KH2xr5/PUcDPZE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725451730; c=relaxed/simple; bh=tudkOBqicCQK4Gxw3wenulSEBK/j0ZtQ4l2gzrY7VeI=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=FsaEQxu4eU4ndHEVgOZLjWkbS0/9hn4dGUVUKsyMiqWFdeysHaAM5zwDcM7EV0t90XEsnAbN6UYTk2xG78hI3Yd5c1cHyHVf4esxP/oQdyEEM7RYazACcwS1ZV24MVeFOy7Ptx6PVNh0gDHYPGI4udGQS6VvVNW7EWpJMR4IHxc= 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=dD/qhVFq; arc=none smtp.client-ip=178.154.239.148 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="dD/qhVFq" Received: from mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net (mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net [IPv6:2a02:6b8:c08:f220:0:640:b85:0]) by forward101b.mail.yandex.net (Yandex) with ESMTPS id 336A560B4A; Wed, 4 Sep 2024 15:08:45 +0300 (MSK) Received: by mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net (smtp/Yandex) with ESMTPSA id h8b9pL7j6Os0-OqhS6W8E; Wed, 04 Sep 2024 15:08:44 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1725451724; bh=zAt49LMWuIYAsshcBExvuI4BWZoXaEJfzbSelIL521w=; h=Message-ID:Date:Cc:Subject:To:From; b=dD/qhVFq2XsHNoIO2EbOWIZ3z1lJcgwroDh4v/bTNbmKlETnjBseCWc2UDtNEeWT3 DbcD++97Aywmr247PV8HLB+NnUm4obH6QqceKvU6Hec7n+u/4e8ZqjCH4nHjRRDsZU G9eaCADQuzGOi32mTtWUIHdabUeE6fTOjagiA4fo= Authentication-Results: mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net; dkim=pass header.i=@yandex.ru From: Dmitry Antipov To: Vinicius Costa Gomes Cc: Jakub Kicinski , Paolo Abeni , Simon Horman , netdev@vger.kernel.org, lvc-project@linuxtesting.org, Dmitry Antipov , syzbot+b65e0af58423fc8a73aa@syzkaller.appspotmail.com Subject: [PATCH net v5 1/2] net: sched: fix use-after-free in taprio_change() Date: Wed, 4 Sep 2024 15:08:41 +0300 Message-ID: <20240904120842.3426084-1-dmantipov@yandex.ru> X-Mailer: git-send-email 2.46.0 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 Acked-by: Vinicius Costa Gomes --- v5: unchanged since v4 but resend due to series change v4: adjust subject to target net tree v3: unchanged since v2 v2: unchanged since v1 --- 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 Sep 4 12:08:42 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Antipov X-Patchwork-Id: 13790703 X-Patchwork-Delegate: kuba@kernel.org Received: from forward103b.mail.yandex.net (forward103b.mail.yandex.net [178.154.239.150]) (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 4C0C31D9324 for ; Wed, 4 Sep 2024 12:08:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.154.239.150 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725451735; cv=none; b=feNf9X9W9turvXFTXq8bWN1YBxg4A3vj+jdQV/B8RqZJKrDr3cWun2D4U+ZN8UgcSBWv0iBRVAKTlYtWiaOIR+IH6VD7T6KAWuLnnfpt5esui/DKVcAA9odn7QvdSaBxxExQhYink3Y83kDAYhZwEAADHTLlMj9C7OJ96ryhn7k= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725451735; c=relaxed/simple; bh=KBIKzSJ2y950AawPCuuqBxxswx//LhgPkuSFy7P+ohs=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Z//B7JNRvxccV1qC8UbvK55ZfYeqzKq6sMZcxM5Jsf3MPo22ollJVtU54eEaCIoZOc0UyS1uc5O6WfaeSVz8KcPWtEF3YAd2YE6mHTGftsqsYt5wiujgw6t3yXG+sU4JpitBm0xeV1cqv4/li1o/lZPqjACovhwvC2jspRRumPY= 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=Ge6JTrj4; arc=none smtp.client-ip=178.154.239.150 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="Ge6JTrj4" Received: from mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net (mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net [IPv6:2a02:6b8:c08:f220:0:640:b85:0]) by forward103b.mail.yandex.net (Yandex) with ESMTPS id 0E254608EF; Wed, 4 Sep 2024 15:08:46 +0300 (MSK) Received: by mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net (smtp/Yandex) with ESMTPSA id h8b9pL7j6Os0-ery1ZJs3; Wed, 04 Sep 2024 15:08:45 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1725451725; bh=ivikaq4vTByAJ8AvPVY5WYjs5UD/23MKHsornkD7C8A=; h=Message-ID:Date:In-Reply-To:Cc:Subject:References:To:From; b=Ge6JTrj4XwrodQ7UTw/t4SuEpOHO11kbAOTSDavkg7+E6su6+oZjuz/kSf9HFYXF3 9zXzaEv18J2SrkhmuC4SNC4ykCkmStwqvgpbERo+kINqWKf72oWnZ09Rt2ytbNRjMK Keti2IhY+j8+liEeouSgQX/gwML8nHRdxGAbP6eE= Authentication-Results: mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net; dkim=pass header.i=@yandex.ru From: Dmitry Antipov To: Vinicius Costa Gomes Cc: Jakub Kicinski , Paolo Abeni , Simon Horman , netdev@vger.kernel.org, lvc-project@linuxtesting.org, Dmitry Antipov Subject: [PATCH net v5 2/2] net: sched: use RCU read-side critical section in taprio_dump() Date: Wed, 4 Sep 2024 15:08:42 +0300 Message-ID: <20240904120842.3426084-2-dmantipov@yandex.ru> X-Mailer: git-send-email 2.46.0 In-Reply-To: <20240904120842.3426084-1-dmantipov@yandex.ru> References: <20240904120842.3426084-1-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 Fix possible use-after-free in 'taprio_dump()' by adding RCU read-side critical section there. Never seen on x86 but found on a KASAN-enabled arm64 system when investigating https://syzkaller.appspot.com/bug?extid=b65e0af58423fc8a73aa: [T15862] BUG: KASAN: slab-use-after-free in taprio_dump+0xa0c/0xbb0 [T15862] Read of size 4 at addr ffff0000d4bb88f8 by task repro/15862 [T15862] [T15862] CPU: 0 UID: 0 PID: 15862 Comm: repro Not tainted 6.11.0-rc1-00293-gdefaf1a2113a-dirty #2 [T15862] Hardware name: QEMU QEMU Virtual Machine, BIOS edk2-20240524-5.fc40 05/24/2024 [T15862] Call trace: [T15862] dump_backtrace+0x20c/0x220 [T15862] show_stack+0x2c/0x40 [T15862] dump_stack_lvl+0xf8/0x174 [T15862] print_report+0x170/0x4d8 [T15862] kasan_report+0xb8/0x1d4 [T15862] __asan_report_load4_noabort+0x20/0x2c [T15862] taprio_dump+0xa0c/0xbb0 [T15862] tc_fill_qdisc+0x540/0x1020 [T15862] qdisc_notify.isra.0+0x330/0x3a0 [T15862] tc_modify_qdisc+0x7b8/0x1838 [T15862] rtnetlink_rcv_msg+0x3c8/0xc20 [T15862] netlink_rcv_skb+0x1f8/0x3d4 [T15862] rtnetlink_rcv+0x28/0x40 [T15862] netlink_unicast+0x51c/0x790 [T15862] netlink_sendmsg+0x79c/0xc20 [T15862] __sock_sendmsg+0xe0/0x1a0 [T15862] ____sys_sendmsg+0x6c0/0x840 [T15862] ___sys_sendmsg+0x1ac/0x1f0 [T15862] __sys_sendmsg+0x110/0x1d0 [T15862] __arm64_sys_sendmsg+0x74/0xb0 [T15862] invoke_syscall+0x88/0x2e0 [T15862] el0_svc_common.constprop.0+0xe4/0x2a0 [T15862] do_el0_svc+0x44/0x60 [T15862] el0_svc+0x50/0x184 [T15862] el0t_64_sync_handler+0x120/0x12c [T15862] el0t_64_sync+0x190/0x194 [T15862] [T15862] Allocated by task 15857: [T15862] kasan_save_stack+0x3c/0x70 [T15862] kasan_save_track+0x20/0x3c [T15862] kasan_save_alloc_info+0x40/0x60 [T15862] __kasan_kmalloc+0xd4/0xe0 [T15862] __kmalloc_cache_noprof+0x194/0x334 [T15862] taprio_change+0x45c/0x2fe0 [T15862] tc_modify_qdisc+0x6a8/0x1838 [T15862] rtnetlink_rcv_msg+0x3c8/0xc20 [T15862] netlink_rcv_skb+0x1f8/0x3d4 [T15862] rtnetlink_rcv+0x28/0x40 [T15862] netlink_unicast+0x51c/0x790 [T15862] netlink_sendmsg+0x79c/0xc20 [T15862] __sock_sendmsg+0xe0/0x1a0 [T15862] ____sys_sendmsg+0x6c0/0x840 [T15862] ___sys_sendmsg+0x1ac/0x1f0 [T15862] __sys_sendmsg+0x110/0x1d0 [T15862] __arm64_sys_sendmsg+0x74/0xb0 [T15862] invoke_syscall+0x88/0x2e0 [T15862] el0_svc_common.constprop.0+0xe4/0x2a0 [T15862] do_el0_svc+0x44/0x60 [T15862] el0_svc+0x50/0x184 [T15862] el0t_64_sync_handler+0x120/0x12c [T15862] el0t_64_sync+0x190/0x194 [T15862] [T15862] Freed by task 6192: [T15862] kasan_save_stack+0x3c/0x70 [T15862] kasan_save_track+0x20/0x3c [T15862] kasan_save_free_info+0x4c/0x80 [T15862] poison_slab_object+0x110/0x160 [T15862] __kasan_slab_free+0x3c/0x74 [T15862] kfree+0x134/0x3c0 [T15862] taprio_free_sched_cb+0x18c/0x220 [T15862] rcu_core+0x920/0x1b7c [T15862] rcu_core_si+0x10/0x1c [T15862] handle_softirqs+0x2e8/0xd64 [T15862] __do_softirq+0x14/0x20 Fixes: 18cdd2f0998a ("net/sched: taprio: taprio_dump and taprio_change are protected by rtnl_mutex") Signed-off-by: Dmitry Antipov Acked-by: Vinicius Costa Gomes --- v5: add Fixes: and resend due to series change v4: redesign to preserve original code as much as possible, adjust commit message and subject to target net tree v3: tweak commit message as suggested by Vinicius v2: added to the series --- net/sched/sch_taprio.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index 59fad74d5ff9..522eec6f92d1 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -2372,9 +2372,6 @@ 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); @@ -2395,18 +2392,23 @@ 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 options_error_rcu; if (oper && dump_schedule(skb, oper)) - goto options_error; + goto options_error_rcu; if (!admin) goto done; sched_nest = nla_nest_start_noflag(skb, TCA_TAPRIO_ATTR_ADMIN_SCHED); if (!sched_nest) - goto options_error; + goto options_error_rcu; if (dump_schedule(skb, admin)) goto admin_error; @@ -2414,11 +2416,15 @@ static int taprio_dump(struct Qdisc *sch, struct sk_buff *skb) nla_nest_end(skb, sched_nest); done: + rcu_read_unlock(); return nla_nest_end(skb, nest); admin_error: nla_nest_cancel(skb, sched_nest); +options_error_rcu: + rcu_read_unlock(); + options_error: nla_nest_cancel(skb, nest);