From patchwork Thu Oct 17 11:25:04 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Antipov X-Patchwork-Id: 13839886 X-Patchwork-Delegate: kuba@kernel.org Received: from forward201b.mail.yandex.net (forward201b.mail.yandex.net [178.154.239.156]) (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 6A89A1D45F3 for ; Thu, 17 Oct 2024 11:32:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.154.239.156 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729164775; cv=none; b=NFe/tYqrTlO0u9L9EbNj0utoeo8TAycM9b6ymlbRx0fqWO2E0px6EK+FpsOxbcXl9Xen12LxaykMHdq3nsF9dmdr/KfsWHu04InEFvhm4hiPeB1GokvvQ0hmEheI/JCmRWLqxHvk8EqcgyUt7NqCqFyDk6yyDSPxh/ATzfo09kk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729164775; c=relaxed/simple; bh=lWbxMZE+o7FcZaOdAJj3fxAgNYvGVZw+2PNr3Wf5kPk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=ZSJNqm/YLD18UX4W8dOhqhA1R8N8SlgU/GWWGdjbFfex3LrBhqpdpd7UBL9ipN1rkvqP3fRlmkcM5VAug99+C8Cq68VzwksxJAP/lPo4uuZDRx/lSxC7QSuMNTcQV3Ag7ipqs3N5VgYr+Rhw9Vd++dwH+G3d4XpJxpGdFILdXp0= 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=UhkvGF0t; arc=none smtp.client-ip=178.154.239.156 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="UhkvGF0t" Received: from forward101b.mail.yandex.net (forward101b.mail.yandex.net [IPv6:2a02:6b8:c02:900:1:45:d181:d101]) by forward201b.mail.yandex.net (Yandex) with ESMTPS id A3532670D7 for ; Thu, 17 Oct 2024 14:26:08 +0300 (MSK) 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:c61f:0:640:7720:0]) by forward101b.mail.yandex.net (Yandex) with ESMTPS id 65F1F60A99; Thu, 17 Oct 2024 14:26:01 +0300 (MSK) Received: by mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net (smtp/Yandex) with ESMTPSA id wPLwlM6xFiE0-xAfQrUWk; Thu, 17 Oct 2024 14:26:00 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1729164360; bh=DS+2lKlxktJJ20yDWr7bzVn6oFVlIMxoi7OnPBvjFUs=; h=Message-ID:Date:In-Reply-To:Cc:Subject:References:To:From; b=UhkvGF0tCMBGHmNcmeU/gJ09Ren0PO9WKR17Of+UIptWzUdJBF6d6VB2gMPP39X4G zXqzm6OQ7zya46rzYtm9E0uOUy23HEcEqDsb2wzADVgpSO3bmMOjxU4iV15rAE2eIz EQ6HUZLQZehzghIPjyxyJfkAznoV+bJMjuO5hwg4= Authentication-Results: mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net; dkim=pass header.i=@yandex.ru From: Dmitry Antipov To: Jakub Kicinski , Paolo Abeni Cc: Vinicius Costa Gomes , netdev@vger.kernel.org, lvc-project@linuxtesting.org, Dmitry Antipov , syzbot+b65e0af58423fc8a73aa@syzkaller.appspotmail.com Subject: [PATCH v6 1/2] net: sched: fix use-after-free in taprio_change() Date: Thu, 17 Oct 2024 14:25:04 +0300 Message-ID: <20241017112546.208758-2-dmantipov@yandex.ru> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241017112546.208758-1-dmantipov@yandex.ru> References: <20241017112546.208758-1-dmantipov@yandex.ru> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Yandex-Filter: 1 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 --- v6: adjust to match recent changes 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 8498d0606b24..9f4e004cdb8b 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1965,7 +1965,8 @@ 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 Thu Oct 17 11:25:05 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Dmitry Antipov X-Patchwork-Id: 13839870 X-Patchwork-Delegate: kuba@kernel.org Received: from forward102b.mail.yandex.net (forward102b.mail.yandex.net [178.154.239.149]) (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 D168A1D9682 for ; Thu, 17 Oct 2024 11:26:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=178.154.239.149 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729164370; cv=none; b=sIB0Uvde8yS+TqWX+f09V6hM2Jg1l+7ipRtzM+2c0PLXgVTPcQ/Ik3HDtrGl3gfLHLhR+fF2/kKJZsUkDQ+JHKUssZSdV+0I9aBsVYRJXWT5wRK8QvtXaW/gD6ovQIlwanGwqvE0sv/nMCLSTvc2Rb4NJ6zkhJKJSd/vL4psnKs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729164370; c=relaxed/simple; bh=6hKqKu5BnEHPdUOYx6Mirfp+hzeNxAKsnCfbjHVtsas=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=E7BH/PU0pQnR6b6eHEmZknL+ID+1iyVREhG3W7xcwYLqNpJ7AN7nK/wwn6JDdxoRtTgKCLZtbaaEJMuJWDeL5cyOnMfdxWEqE0+RkD+LUWrgwIKFDCgpxRbL+ofUrCkcBmzW3DhIsBGxPKoVApFOF7t9JyZ6IMHRjh3TrKNzAMI= 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=pXeQcEtJ; arc=none smtp.client-ip=178.154.239.149 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="pXeQcEtJ" 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:c61f:0:640:7720:0]) by forward102b.mail.yandex.net (Yandex) with ESMTPS id A2D2B60A0B; Thu, 17 Oct 2024 14:26:02 +0300 (MSK) Received: by mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net (smtp/Yandex) with ESMTPSA id wPLwlM6xFiE0-2g4nSVtS; Thu, 17 Oct 2024 14:26:01 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1729164361; bh=VpMELRrrif7Xwagkeyo71ve6U4WAEJqFkL1YyQZApUE=; h=Message-ID:Date:In-Reply-To:Cc:Subject:References:To:From; b=pXeQcEtJBVI5tDHjAeVg2voNAgKLQh3wedACtzMW6lLEAdSvGtwfMB6zk6TM5c5C0 xZzI0trOaHRuZL/IDi8RXkIVcy8HtWBjeMurFrhpULWCktK9Du465CQNksBJpBMT2Y OsTLRUWQu4Z6jmPteN7CIqTuTS/Epz1fFpxq1wPk= Authentication-Results: mail-nwsmtp-smtp-production-main-39.sas.yp-c.yandex.net; dkim=pass header.i=@yandex.ru From: Dmitry Antipov To: Jakub Kicinski , Paolo Abeni Cc: Vinicius Costa Gomes , netdev@vger.kernel.org, lvc-project@linuxtesting.org, Dmitry Antipov Subject: [PATCH v6 2/2] net: sched: use RCU read-side critical section in taprio_dump() Date: Thu, 17 Oct 2024 14:25:05 +0300 Message-ID: <20241017112546.208758-3-dmantipov@yandex.ru> X-Mailer: git-send-email 2.47.0 In-Reply-To: <20241017112546.208758-1-dmantipov@yandex.ru> References: <20241017112546.208758-1-dmantipov@yandex.ru> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Yandex-Filter: 1 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 --- v6: adjust to match recent changes 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 9f4e004cdb8b..8623dc0bafc0 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); @@ -2397,18 +2394,23 @@ 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; @@ -2416,11 +2418,15 @@ 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);