From patchwork Fri May 26 17:19:09 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fedor Pchelkin X-Patchwork-Id: 13257217 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 8C76528C29 for ; Fri, 26 May 2023 17:20:04 +0000 (UTC) Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E38F125; Fri, 26 May 2023 10:19:50 -0700 (PDT) Received: from fpc.intra.ispras.ru (unknown [10.10.165.11]) by mail.ispras.ru (Postfix) with ESMTPSA id 2AF5B40737DC; Fri, 26 May 2023 17:19:47 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ispras.ru 2AF5B40737DC DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ispras.ru; s=default; t=1685121587; bh=Cc+0l3WE7NSHNX8IIVLOGJ444B7c/feMyWd0rLDcJoc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sbVNOgNvzcWPAtC2+Q327iOEkePkSJfoEmS2k204zuPCOOuDee/3FhflR9QyxrGSW VcO9RpfK7HsQL0Lr2j/v7fdAYybNF5XLWDME/Ilw7I3k7s7NMe1fW2JhfpbhZ9EP7Y 8yGlUMP6Ho2VP/OXRL9EiEms6QVoJBgarapisQKM= From: Fedor Pchelkin To: Oleksij Rempel Cc: Fedor Pchelkin , Marc Kleine-Budde , kernel@pengutronix.de, Robin van der Gracht , Oliver Hartkopp , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Kurt Van Dijck , linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Alexey Khoroshilov , lvc-project@linuxtesting.org Subject: [PATCH 1/2] can: j1939: change j1939_netdev_lock type to mutex Date: Fri, 26 May 2023 20:19:09 +0300 Message-Id: <20230526171910.227615-2-pchelkin@ispras.ru> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230526171910.227615-1-pchelkin@ispras.ru> References: <20230526171910.227615-1-pchelkin@ispras.ru> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org It turns out access to j1939_can_rx_register() needs to be serialized, otherwise j1939_priv can be corrupted when parallel threads call j1939_netdev_start() and j1939_can_rx_register() fails. This issue is thoroughly covered in other commit which serializes access to j1939_can_rx_register(). Change j1939_netdev_lock type to mutex so that we do not need to remove GFP_KERNEL from can_rx_register(). j1939_netdev_lock seems to be used in normal contexts where mutex usage is not prohibited. Found by Linux Verification Center (linuxtesting.org) with Syzkaller. Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Suggested-by: Alexey Khoroshilov Signed-off-by: Fedor Pchelkin Tested-by: Oleksij Rempel Acked-by: Oleksij Rempel --- Note that it has been only tested via Syzkaller and not with real hardware. net/can/j1939/main.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c index 821d4ff303b3..6ed79afe19a5 100644 --- a/net/can/j1939/main.c +++ b/net/can/j1939/main.c @@ -126,7 +126,7 @@ static void j1939_can_recv(struct sk_buff *iskb, void *data) #define J1939_CAN_ID CAN_EFF_FLAG #define J1939_CAN_MASK (CAN_EFF_FLAG | CAN_RTR_FLAG) -static DEFINE_SPINLOCK(j1939_netdev_lock); +static DEFINE_MUTEX(j1939_netdev_lock); static struct j1939_priv *j1939_priv_create(struct net_device *ndev) { @@ -220,7 +220,7 @@ static void __j1939_rx_release(struct kref *kref) j1939_can_rx_unregister(priv); j1939_ecu_unmap_all(priv); j1939_priv_set(priv->ndev, NULL); - spin_unlock(&j1939_netdev_lock); + mutex_unlock(&j1939_netdev_lock); } /* get pointer to priv without increasing ref counter */ @@ -248,9 +248,9 @@ static struct j1939_priv *j1939_priv_get_by_ndev(struct net_device *ndev) { struct j1939_priv *priv; - spin_lock(&j1939_netdev_lock); + mutex_lock(&j1939_netdev_lock); priv = j1939_priv_get_by_ndev_locked(ndev); - spin_unlock(&j1939_netdev_lock); + mutex_unlock(&j1939_netdev_lock); return priv; } @@ -260,14 +260,14 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev) struct j1939_priv *priv, *priv_new; int ret; - spin_lock(&j1939_netdev_lock); + mutex_lock(&j1939_netdev_lock); priv = j1939_priv_get_by_ndev_locked(ndev); if (priv) { kref_get(&priv->rx_kref); - spin_unlock(&j1939_netdev_lock); + mutex_unlock(&j1939_netdev_lock); return priv; } - spin_unlock(&j1939_netdev_lock); + mutex_unlock(&j1939_netdev_lock); priv = j1939_priv_create(ndev); if (!priv) @@ -277,20 +277,20 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev) spin_lock_init(&priv->j1939_socks_lock); INIT_LIST_HEAD(&priv->j1939_socks); - spin_lock(&j1939_netdev_lock); + mutex_lock(&j1939_netdev_lock); priv_new = j1939_priv_get_by_ndev_locked(ndev); if (priv_new) { /* Someone was faster than us, use their priv and roll * back our's. */ kref_get(&priv_new->rx_kref); - spin_unlock(&j1939_netdev_lock); + mutex_unlock(&j1939_netdev_lock); dev_put(ndev); kfree(priv); return priv_new; } j1939_priv_set(ndev, priv); - spin_unlock(&j1939_netdev_lock); + mutex_unlock(&j1939_netdev_lock); ret = j1939_can_rx_register(priv); if (ret < 0) @@ -308,7 +308,7 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev) void j1939_netdev_stop(struct j1939_priv *priv) { - kref_put_lock(&priv->rx_kref, __j1939_rx_release, &j1939_netdev_lock); + kref_put_mutex(&priv->rx_kref, __j1939_rx_release, &j1939_netdev_lock); j1939_priv_put(priv); } From patchwork Fri May 26 17:19:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Fedor Pchelkin X-Patchwork-Id: 13257218 X-Patchwork-Delegate: kuba@kernel.org Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 11F8428C37 for ; Fri, 26 May 2023 17:20:05 +0000 (UTC) Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 71345FB; Fri, 26 May 2023 10:19:50 -0700 (PDT) Received: from fpc.intra.ispras.ru (unknown [10.10.165.11]) by mail.ispras.ru (Postfix) with ESMTPSA id AF9EF4076265; Fri, 26 May 2023 17:19:48 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ispras.ru AF9EF4076265 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ispras.ru; s=default; t=1685121588; bh=Aku6F9F7nJAWf3z4o7yAlajfp8XKuCevG3Zt7WjhiDY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OsLySGzEVwhZhGSG+jB3drYD7RzpV9urE1wW3k33kPOJT56woMTeBA2sn1L+u3fSM 9sYAO4mCR4/VqNe8a5awRnFS6aajuXl4XN3r/ianA4E7ATMZ/Te7Gyu1GZ30y2Eo4y z2x9Mz2/xkVf1niQk6JqwNeQpY5WHCisuXrNpzKs= From: Fedor Pchelkin To: Oleksij Rempel Cc: Fedor Pchelkin , Marc Kleine-Budde , kernel@pengutronix.de, Robin van der Gracht , Oliver Hartkopp , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Kurt Van Dijck , linux-can@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Alexey Khoroshilov , lvc-project@linuxtesting.org Subject: [PATCH 2/2] can: j1939: avoid possible use-after-free when j1939_can_rx_register fails Date: Fri, 26 May 2023 20:19:10 +0300 Message-Id: <20230526171910.227615-3-pchelkin@ispras.ru> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230526171910.227615-1-pchelkin@ispras.ru> References: <20230526171910.227615-1-pchelkin@ispras.ru> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_NONE,SPF_PASS, T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Patchwork-Delegate: kuba@kernel.org 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 --- net/can/j1939/main.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/net/can/j1939/main.c b/net/can/j1939/main.c index 6ed79afe19a5..ecff1c947d68 100644 --- a/net/can/j1939/main.c +++ b/net/can/j1939/main.c @@ -290,16 +290,18 @@ struct j1939_priv *j1939_netdev_start(struct net_device *ndev) 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);