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 9D647C7619A for ; Mon, 27 Mar 2023 12:48:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232381AbjC0MsX (ORCPT ); Mon, 27 Mar 2023 08:48:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45850 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232009AbjC0MsR (ORCPT ); Mon, 27 Mar 2023 08:48:17 -0400 Received: from metis.ext.pengutronix.de (metis.ext.pengutronix.de [IPv6:2001:67c:670:201:290:27ff:fe1d:cc33]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BD48640FC for ; Mon, 27 Mar 2023 05:48:16 -0700 (PDT) Received: from moin.white.stw.pengutronix.de ([2a0a:edc0:0:b01:1d::7b] helo=bjornoya.blackshift.org) by metis.ext.pengutronix.de with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1pgmGl-0000c2-57 for linux-can@vger.kernel.org; Mon, 27 Mar 2023 14:48:15 +0200 Received: from dspam.blackshift.org (localhost [127.0.0.1]) by bjornoya.blackshift.org (Postfix) with SMTP id 79BA519D3C0 for ; Mon, 27 Mar 2023 12:48:14 +0000 (UTC) Received: from hardanger.blackshift.org (unknown [172.20.34.65]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by bjornoya.blackshift.org (Postfix) with ESMTPS id 1ACD219D3AD; Mon, 27 Mar 2023 12:48:12 +0000 (UTC) Received: from blackshift.org (localhost [::1]) by hardanger.blackshift.org (OpenSMTPD) with ESMTP id a51f1b82; Mon, 27 Mar 2023 12:48:09 +0000 (UTC) From: Marc Kleine-Budde To: netdev@vger.kernel.org Cc: davem@davemloft.net, kuba@kernel.org, linux-can@vger.kernel.org, kernel@pengutronix.de, Ivan Orlov , syzbot+c9bfd85eca611ebf5db1@syzkaller.appspotmail.com, Oliver Hartkopp , Marc Kleine-Budde Subject: [PATCH net 2/2] can: bcm: bcm_tx_setup(): fix KMSAN uninit-value in vfs_write Date: Mon, 27 Mar 2023 14:48:07 +0200 Message-Id: <20230327124807.1157134-3-mkl@pengutronix.de> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230327124807.1157134-1-mkl@pengutronix.de> References: <20230327124807.1157134-1-mkl@pengutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SA-Exim-Connect-IP: 2a0a:edc0:0:b01:1d::7b X-SA-Exim-Mail-From: mkl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-can@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org From: Ivan Orlov 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 --- 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 27706f6ace34..a962ec2b8ba5 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -941,6 +941,8 @@ 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) @@ -950,12 +952,8 @@ 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 */ @@ -1026,6 +1024,12 @@ 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