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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C1497C7EE2E for ; Mon, 12 Jun 2023 10:53:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235876AbjFLKxd (ORCPT ); Mon, 12 Jun 2023 06:53:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55606 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236165AbjFLKxK (ORCPT ); Mon, 12 Jun 2023 06:53:10 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D0C0BAD17 for ; Mon, 12 Jun 2023 03:37:53 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 6CEA462204 for ; Mon, 12 Jun 2023 10:37:53 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 81079C433EF; Mon, 12 Jun 2023 10:37:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1686566272; bh=y1ls9yVThGHSWeAxmGINhyREKrialOO1zacee2PdI4M=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GXwgMFWcZUebtPy9GXcyGsWOjwcGbzk6NvtwrlECU3jUu4gG8F4f+R/Q9Gq3AzpzL zddH6OJTopkZLMegeQG8m7nCs6cZpx57lQ33xIjKqAMKPeaBNo8RTvrylTZNRH5igv nOBtW2NSxUyA8hjcV69qi/XfPlDwn6Kz/ExrLQog= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Fedor Pchelkin , Oleksij Rempel , Marc Kleine-Budde Subject: [PATCH 5.15 60/91] can: j1939: avoid possible use-after-free when j1939_can_rx_register fails Date: Mon, 12 Jun 2023 12:26:49 +0200 Message-ID: <20230612101704.565318357@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230612101702.085813286@linuxfoundation.org> References: <20230612101702.085813286@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Fedor Pchelkin commit 9f16eb106aa5fce15904625661312623ec783ed3 upstream. Syzkaller reports the following failure: BUG: KASAN: use-after-free in kref_put include/linux/kref.h:64 [inline] BUG: KASAN: use-after-free in j1939_priv_put+0x25/0xa0 net/can/j1939/main.c:172 Write of size 4 at addr ffff888141c15058 by task swapper/3/0 CPU: 3 PID: 0 Comm: swapper/3 Not tainted 5.10.144-syzkaller #0 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x107/0x167 lib/dump_stack.c:118 print_address_description.constprop.0+0x1c/0x220 mm/kasan/report.c:385 __kasan_report mm/kasan/report.c:545 [inline] kasan_report.cold+0x1f/0x37 mm/kasan/report.c:562 check_memory_region_inline mm/kasan/generic.c:186 [inline] check_memory_region+0x145/0x190 mm/kasan/generic.c:192 instrument_atomic_read_write include/linux/instrumented.h:101 [inline] atomic_fetch_sub_release include/asm-generic/atomic-instrumented.h:220 [inline] __refcount_sub_and_test include/linux/refcount.h:272 [inline] __refcount_dec_and_test include/linux/refcount.h:315 [inline] refcount_dec_and_test include/linux/refcount.h:333 [inline] kref_put include/linux/kref.h:64 [inline] j1939_priv_put+0x25/0xa0 net/can/j1939/main.c:172 j1939_sk_sock_destruct+0x44/0x90 net/can/j1939/socket.c:374 __sk_destruct+0x4e/0x820 net/core/sock.c:1784 rcu_do_batch kernel/rcu/tree.c:2485 [inline] rcu_core+0xb35/0x1a30 kernel/rcu/tree.c:2726 __do_softirq+0x289/0x9a3 kernel/softirq.c:298 asm_call_irq_on_stack+0x12/0x20 __run_on_irqstack arch/x86/include/asm/irq_stack.h:26 [inline] run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:77 [inline] do_softirq_own_stack+0xaa/0xe0 arch/x86/kernel/irq_64.c:77 invoke_softirq kernel/softirq.c:393 [inline] __irq_exit_rcu kernel/softirq.c:423 [inline] irq_exit_rcu+0x136/0x200 kernel/softirq.c:435 sysvec_apic_timer_interrupt+0x4d/0x100 arch/x86/kernel/apic/apic.c:1095 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:635 Allocated by task 1141: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc.constprop.0+0xc9/0xd0 mm/kasan/common.c:461 kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:664 [inline] j1939_priv_create net/can/j1939/main.c:131 [inline] j1939_netdev_start+0x111/0x860 net/can/j1939/main.c:268 j1939_sk_bind+0x8ea/0xd30 net/can/j1939/socket.c:485 __sys_bind+0x1f2/0x260 net/socket.c:1645 __do_sys_bind net/socket.c:1656 [inline] __se_sys_bind net/socket.c:1654 [inline] __x64_sys_bind+0x6f/0xb0 net/socket.c:1654 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xc6 Freed by task 1141: kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48 kasan_set_track+0x1c/0x30 mm/kasan/common.c:56 kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0x112/0x170 mm/kasan/common.c:422 slab_free_hook mm/slub.c:1542 [inline] slab_free_freelist_hook+0xad/0x190 mm/slub.c:1576 slab_free mm/slub.c:3149 [inline] kfree+0xd9/0x3b0 mm/slub.c:4125 j1939_netdev_start+0x5ee/0x860 net/can/j1939/main.c:300 j1939_sk_bind+0x8ea/0xd30 net/can/j1939/socket.c:485 __sys_bind+0x1f2/0x260 net/socket.c:1645 __do_sys_bind net/socket.c:1656 [inline] __se_sys_bind net/socket.c:1654 [inline] __x64_sys_bind+0x6f/0xb0 net/socket.c:1654 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x61/0xc6 It can be caused by this scenario: CPU0 CPU1 j1939_sk_bind(socket0, ndev0, ...) j1939_netdev_start() j1939_sk_bind(socket1, ndev0, ...) j1939_netdev_start() mutex_lock(&j1939_netdev_lock) j1939_priv_set(ndev0, priv) mutex_unlock(&j1939_netdev_lock) if (priv_new) kref_get(&priv_new->rx_kref) return priv_new; /* inside j1939_sk_bind() */ jsk->priv = priv j1939_can_rx_register(priv) // fails j1939_priv_set(ndev, NULL) kfree(priv) j1939_sk_sock_destruct() j1939_priv_put() // <- uaf To avoid this, call j1939_can_rx_register() under j1939_netdev_lock so that a concurrent thread cannot process j1939_priv before j1939_can_rx_register() returns. Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Signed-off-by: Fedor Pchelkin Tested-by: Oleksij Rempel Acked-by: Oleksij Rempel Link: https://lore.kernel.org/r/20230526171910.227615-3-pchelkin@ispras.ru Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- net/can/j1939/main.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/net/can/j1939/main.c +++ b/net/can/j1939/main.c @@ -286,16 +286,18 @@ struct j1939_priv *j1939_netdev_start(st return priv_new; } j1939_priv_set(ndev, priv); - mutex_unlock(&j1939_netdev_lock); ret = j1939_can_rx_register(priv); if (ret < 0) goto out_priv_put; + mutex_unlock(&j1939_netdev_lock); return priv; out_priv_put: j1939_priv_set(ndev, NULL); + mutex_unlock(&j1939_netdev_lock); + dev_put(ndev); kfree(priv);