From patchwork Wed Jun 29 10:49:41 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Duoming Zhou X-Patchwork-Id: 12899758 X-Patchwork-Delegate: kuba@kernel.org 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 0CEFCC43334 for ; Wed, 29 Jun 2022 10:50:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232745AbiF2KuW (ORCPT ); Wed, 29 Jun 2022 06:50:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56874 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232597AbiF2KuU (ORCPT ); Wed, 29 Jun 2022 06:50:20 -0400 Received: from zju.edu.cn (mail.zju.edu.cn [61.164.42.155]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 9C4C01EC54; Wed, 29 Jun 2022 03:50:18 -0700 (PDT) Received: from ubuntu.localdomain (unknown [10.190.68.163]) by mail-app3 (Coremail) with SMTP id cC_KCgCH_0JKLrxiJU0gAQ--.277S2; Wed, 29 Jun 2022 18:49:59 +0800 (CST) From: Duoming Zhou To: linux-hams@vger.kernel.org Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org, ralf@linux-mips.org, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, Duoming Zhou Subject: [PATCH v4] net: rose: fix null-ptr-deref caused by rose_kill_by_neigh Date: Wed, 29 Jun 2022 18:49:41 +0800 Message-Id: <20220629104941.26351-1-duoming@zju.edu.cn> X-Mailer: git-send-email 2.17.1 X-CM-TRANSID: cC_KCgCH_0JKLrxiJU0gAQ--.277S2 X-Coremail-Antispam: 1UD129KBjvJXoWxJw1fGr1kXFyrXw4fAFWfGrg_yoW5tF4Dpr 9xKrW3Grs7Jws8WFsrJF18ur4FvF1q9F9rWrW09F92y3Z8GrWjvrykKFWUWr15XFsrGFya gF1UW3ySyrnFyw7anT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDU0xBIdaVrnRJUUUka1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s1l1IIY67AE w4v_Jr0_Jr4l8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xvwVC0I7IYx2 IY67AKxVWDJVCq3wA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVW8Jr0_Cr1UM28EF7xvwVC2 z280aVAFwI0_GcCE3s1l84ACjcxK6I8E87Iv6xkF7I0E14v26rxl6s0DM2AIxVAIcxkEcV Aq07x20xvEncxIr21l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r1j 6r18McIj6I8E87Iv67AKxVWUJVW8JwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IYc2Ij64 vIr41lF7I21c0EjII2zVCS5cI20VAGYxC7MxAIw28IcxkI7VAKI48JMxAIw28IcVCjz48v 1sIEY20_GFWkJr1UJwCFx2IqxVCFs4IE7xkEbVWUJVW8JwC20s026c02F40E14v26r1j6r 18MI8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vI r41lIxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Jr0_Gr 1lIxAIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvE x4A2jsIEc7CjxVAFwI0_Gr0_Gr1UYxBIdaVFxhVjvjDU0xZFpf9x0JUdHUDUUUUU= X-CM-SenderInfo: qssqjiasttq6lmxovvfxof0/1tbiAgoQAVZdtadZFgANsC Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: kuba@kernel.org When the link layer connection is broken, the rose->neighbour is set to null. But rose->neighbour could be used by rose_connection() and rose_release() later, because there is no synchronization among them. As a result, the null-ptr-deref bugs will happen. One of the null-ptr-deref bugs is shown below: (thread 1) | (thread 2) | rose_connect rose_kill_by_neigh | lock_sock(sk) spin_lock_bh(&rose_list_lock) | if (!rose->neighbour) rose->neighbour = NULL;//(1) | | rose->neighbour->use++;//(2) The rose->neighbour is set to null in position (1) and dereferenced in position (2). The KASAN report triggered by POC is shown below: KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] ... RIP: 0010:rose_connect+0x6c2/0xf30 RSP: 0018:ffff88800ab47d60 EFLAGS: 00000206 RAX: 0000000000000005 RBX: 000000000000002a RCX: 0000000000000000 RDX: ffff88800ab38000 RSI: ffff88800ab47e48 RDI: ffff88800ab38309 RBP: dffffc0000000000 R08: 0000000000000000 R09: ffffed1001567062 R10: dfffe91001567063 R11: 1ffff11001567061 R12: 1ffff11000d17cd0 R13: ffff8880068be680 R14: 0000000000000002 R15: 1ffff11000d17cd0 ... Call Trace: ? __local_bh_enable_ip+0x54/0x80 ? selinux_netlbl_socket_connect+0x26/0x30 ? rose_bind+0x5b0/0x5b0 __sys_connect+0x216/0x280 __x64_sys_connect+0x71/0x80 do_syscall_64+0x43/0x90 entry_SYSCALL_64_after_hwframe+0x46/0xb0 This patch adds lock_sock() in rose_kill_by_neigh() in order to synchronize with rose_connect() and rose_release(). Meanwhile, this patch adds sock_hold() protected by rose_list_lock that could synchronize with rose_remove_socket() in order to mitigate UAF bug caused by lock_sock() we add. What's more, there is no need using rose_neigh_list_lock to protect rose_kill_by_neigh(). Because we have already used rose_neigh_list_lock to protect the state change of rose_neigh in rose_link_failed(), which is well synchronized. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Duoming Zhou --- Changes in v4: - v4: Fix traversing erroneously stop problem. net/rose/af_rose.c | 8 ++++++++ net/rose/rose_route.c | 2 ++ 2 files changed, 10 insertions(+) diff --git a/net/rose/af_rose.c b/net/rose/af_rose.c index bf2d986a6bc..24dcbde88fb 100644 --- a/net/rose/af_rose.c +++ b/net/rose/af_rose.c @@ -165,13 +165,21 @@ void rose_kill_by_neigh(struct rose_neigh *neigh) struct sock *s; spin_lock_bh(&rose_list_lock); +again: sk_for_each(s, &rose_list) { struct rose_sock *rose = rose_sk(s); if (rose->neighbour == neigh) { + sock_hold(s); + spin_unlock_bh(&rose_list_lock); + lock_sock(s); rose_disconnect(s, ENETUNREACH, ROSE_OUT_OF_ORDER, 0); rose->neighbour->use--; rose->neighbour = NULL; + release_sock(s); + spin_lock_bh(&rose_list_lock); + sock_put(s); + goto again; } } spin_unlock_bh(&rose_list_lock); diff --git a/net/rose/rose_route.c b/net/rose/rose_route.c index fee6409c2bb..b116828b422 100644 --- a/net/rose/rose_route.c +++ b/net/rose/rose_route.c @@ -827,7 +827,9 @@ void rose_link_failed(ax25_cb *ax25, int reason) ax25_cb_put(ax25); rose_del_route_by_neigh(rose_neigh); + spin_unlock_bh(&rose_neigh_list_lock); rose_kill_by_neigh(rose_neigh); + return; } spin_unlock_bh(&rose_neigh_list_lock); }