From patchwork Mon Aug 24 08:30:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 265150 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-13.7 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9017CC433E5 for ; Mon, 24 Aug 2020 08:49:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F1BE2074D for ; Mon, 24 Aug 2020 08:49:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598258970; bh=H4PJW85OSbOIF1DQ4hnrfqyHQL20ozcmuZlOID6RNzg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=LW7C/mFegHbTbkZtXc3Yts9bFGQUsHivk08pfjVaJFLTNbWiYT62OLG2yb+1kUWib sVWEoFIxIi67wtZyT2HuCUrQghwtFAcwJlZbreqEXKXGYe/P5vpN6gaEVYoteSDBUD EjRJVdFfMs0vuR1EhjEZvCMs7gBETQFGHMiKV0sc= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729717AbgHXIt3 (ORCPT ); Mon, 24 Aug 2020 04:49:29 -0400 Received: from mail.kernel.org ([198.145.29.99]:51692 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729710AbgHXItY (ORCPT ); Mon, 24 Aug 2020 04:49:24 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B07BA206F0; Mon, 24 Aug 2020 08:49:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1598258964; bh=H4PJW85OSbOIF1DQ4hnrfqyHQL20ozcmuZlOID6RNzg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=F1xCvcPirmOz2VG+TVpGiCCXLjWJayKxdbBqs3UpAxaZ03CMfDjmZGiE6ksb8Wuxz vFr1l4voS2LsOlCPh0yISUnfm6Bvt+IbF+X4xW8kr9dA71cf7wahRSVriv4kFkO4xZ Anv4cT/lYWtRxUe+JbrWIO3p47zvkRN12skHE/3M= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Eric Dumazet , syzbot , Robin van der Gracht , Oleksij Rempel , Pengutronix Kernel Team , linux-can@vger.kernel.org, Marc Kleine-Budde , Sasha Levin Subject: [PATCH 5.4 070/107] can: j1939: fix kernel-infoleak in j1939_sk_sock2sockaddr_can() Date: Mon, 24 Aug 2020 10:30:36 +0200 Message-Id: <20200824082408.590017649@linuxfoundation.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200824082405.020301642@linuxfoundation.org> References: <20200824082405.020301642@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Eric Dumazet [ Upstream commit 38ba8b9241f5848a49b80fddac9ab5f4692e434e ] syzbot found that at least 2 bytes of kernel information were leaked during getsockname() on AF_CAN CAN_J1939 socket. Since struct sockaddr_can has in fact two holes, simply clear the whole area before filling it with useful data. BUG: KMSAN: kernel-infoleak in kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253 CPU: 0 PID: 8466 Comm: syz-executor511 Not tainted 5.8.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x21c/0x280 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121 kmsan_internal_check_memory+0x238/0x3d0 mm/kmsan/kmsan.c:423 kmsan_copy_to_user+0x81/0x90 mm/kmsan/kmsan_hooks.c:253 instrument_copy_to_user include/linux/instrumented.h:91 [inline] _copy_to_user+0x18e/0x260 lib/usercopy.c:39 copy_to_user include/linux/uaccess.h:186 [inline] move_addr_to_user+0x3de/0x670 net/socket.c:237 __sys_getsockname+0x407/0x5e0 net/socket.c:1909 __do_sys_getsockname net/socket.c:1920 [inline] __se_sys_getsockname+0x91/0xb0 net/socket.c:1917 __x64_sys_getsockname+0x4a/0x70 net/socket.c:1917 do_syscall_64+0xad/0x160 arch/x86/entry/common.c:386 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x440219 Code: Bad RIP value. RSP: 002b:00007ffe5ee150c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000033 RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 0000000000440219 RDX: 0000000020000240 RSI: 0000000020000100 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 0000000000000000 R09: 00000000004002c8 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000401a20 R13: 0000000000401ab0 R14: 0000000000000000 R15: 0000000000000000 Local variable ----address@__sys_getsockname created at: __sys_getsockname+0x91/0x5e0 net/socket.c:1894 __sys_getsockname+0x91/0x5e0 net/socket.c:1894 Bytes 2-3 of 24 are uninitialized Memory access of size 24 starts at ffff8880ba2c7de8 Data copied to user address 0000000020000100 Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Signed-off-by: Eric Dumazet Reported-by: syzbot Cc: Robin van der Gracht Cc: Oleksij Rempel Cc: Pengutronix Kernel Team Cc: linux-can@vger.kernel.org Acked-by: Oleksij Rempel Link: https://lore.kernel.org/r/20200813161834.4021638-1-edumazet@google.com Signed-off-by: Marc Kleine-Budde Signed-off-by: Sasha Levin --- net/can/j1939/socket.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/can/j1939/socket.c b/net/can/j1939/socket.c index 11d566c70a944..1b7dc1a8547f3 100644 --- a/net/can/j1939/socket.c +++ b/net/can/j1939/socket.c @@ -561,6 +561,11 @@ static int j1939_sk_connect(struct socket *sock, struct sockaddr *uaddr, static void j1939_sk_sock2sockaddr_can(struct sockaddr_can *addr, const struct j1939_sock *jsk, int peer) { + /* There are two holes (2 bytes and 3 bytes) to clear to avoid + * leaking kernel information to user space. + */ + memset(addr, 0, J1939_MIN_NAMELEN); + addr->can_family = AF_CAN; addr->can_ifindex = jsk->ifindex; addr->can_addr.j1939.pgn = jsk->addr.pgn;