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 6A5E5C76196 for ; Mon, 3 Apr 2023 14:18:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233005AbjDCOSi (ORCPT ); Mon, 3 Apr 2023 10:18:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38202 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233011AbjDCOSh (ORCPT ); Mon, 3 Apr 2023 10:18:37 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3C8752C9D6 for ; Mon, 3 Apr 2023 07:18:36 -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 C1EE061A2D for ; Mon, 3 Apr 2023 14:18:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D6E74C433EF; Mon, 3 Apr 2023 14:18:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1680531515; bh=R0oJA7TgNtTlD6/a1l9JKsyxkJ0quP1uLw9XH9XglCw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=doyCgaZl0mKwd/0Y7czosXIkoid02zEqp36jzJORZLYcbvVE1YqGdkzgGXzZPVtDI i00QmUKMBkxDzEPD11x+xcAlbDnFNY9YEHRYXz7eHhZ8irSJD0xNisskYZwLPfXwDh Z8aTwT5Q7bAiC/Jr5LauAs1IhlBeSmgqmj0gfB24= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+c9bfd85eca611ebf5db1@syzkaller.appspotmail.com, Ivan Orlov , Oliver Hartkopp , Marc Kleine-Budde , Sasha Levin Subject: [PATCH 4.19 63/84] can: bcm: bcm_tx_setup(): fix KMSAN uninit-value in vfs_write Date: Mon, 3 Apr 2023 16:09:04 +0200 Message-Id: <20230403140355.601224526@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230403140353.406927418@linuxfoundation.org> References: <20230403140353.406927418@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: Ivan Orlov [ Upstream commit 2b4c99f7d9a57ecd644eda9b1fb0a1072414959f ] Syzkaller reported the following issue: ===================================================== BUG: KMSAN: uninit-value in aio_rw_done fs/aio.c:1520 [inline] BUG: KMSAN: uninit-value in aio_write+0x899/0x950 fs/aio.c:1600 aio_rw_done fs/aio.c:1520 [inline] aio_write+0x899/0x950 fs/aio.c:1600 io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019 __do_sys_io_submit fs/aio.c:2078 [inline] __se_sys_io_submit+0x293/0x770 fs/aio.c:2048 __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Uninit was created at: slab_post_alloc_hook mm/slab.h:766 [inline] slab_alloc_node mm/slub.c:3452 [inline] __kmem_cache_alloc_node+0x71f/0xce0 mm/slub.c:3491 __do_kmalloc_node mm/slab_common.c:967 [inline] __kmalloc+0x11d/0x3b0 mm/slab_common.c:981 kmalloc_array include/linux/slab.h:636 [inline] bcm_tx_setup+0x80e/0x29d0 net/can/bcm.c:930 bcm_sendmsg+0x3a2/0xce0 net/can/bcm.c:1351 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg net/socket.c:734 [inline] sock_write_iter+0x495/0x5e0 net/socket.c:1108 call_write_iter include/linux/fs.h:2189 [inline] aio_write+0x63a/0x950 fs/aio.c:1600 io_submit_one+0x1d1c/0x3bf0 fs/aio.c:2019 __do_sys_io_submit fs/aio.c:2078 [inline] __se_sys_io_submit+0x293/0x770 fs/aio.c:2048 __x64_sys_io_submit+0x92/0xd0 fs/aio.c:2048 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd CPU: 1 PID: 5034 Comm: syz-executor350 Not tainted 6.2.0-rc6-syzkaller-80422-geda666ff2276 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023 ===================================================== We can follow the call chain and find that 'bcm_tx_setup' function calls 'memcpy_from_msg' to copy some content to the newly allocated frame of 'op->frames'. After that the 'len' field of copied structure being compared with some constant value (64 or 8). However, if 'memcpy_from_msg' returns an error, we will compare some uninitialized memory. This triggers 'uninit-value' issue. This patch will add 'memcpy_from_msg' possible errors processing to avoid uninit-value issue. Tested via syzkaller Reported-by: syzbot+c9bfd85eca611ebf5db1@syzkaller.appspotmail.com Link: https://syzkaller.appspot.com/bug?id=47f897f8ad958bbde5790ebf389b5e7e0a345089 Signed-off-by: Ivan Orlov Fixes: 6f3b911d5f29b ("can: bcm: add support for CAN FD frames") Acked-by: Oliver Hartkopp Link: https://lore.kernel.org/all/20230314120445.12407-1-ivan.orlov0322@gmail.com Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin --- net/can/bcm.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) diff --git a/net/can/bcm.c b/net/can/bcm.c index 74e555a22de75..61269cc2fa828 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -935,6 +935,8 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, cf = op->frames + op->cfsiz * i; err = memcpy_from_msg((u8 *)cf, msg, op->cfsiz); + if (err < 0) + goto free_op; if (op->flags & CAN_FD_FRAME) { if (cf->len > 64) @@ -944,12 +946,8 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, err = -EINVAL; } - if (err < 0) { - if (op->frames != &op->sframe) - kfree(op->frames); - kfree(op); - return err; - } + if (err < 0) + goto free_op; if (msg_head->flags & TX_CP_CAN_ID) { /* copy can_id into frame */ @@ -1020,6 +1018,12 @@ static int bcm_tx_setup(struct bcm_msg_head *msg_head, struct msghdr *msg, bcm_tx_start_timer(op); return msg_head->nframes * op->cfsiz + MHSIZ; + +free_op: + if (op->frames != &op->sframe) + kfree(op->frames); + kfree(op); + return err; } /* -- 2.39.2