From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 2802B15218A; Tue, 2 Jul 2024 17:24:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719941082; cv=none; b=C46Zt5g20U9sAMtdR5RgDtigi9c5wSYh6kaZi5cTs28M0L1JXoN+f14R2yywBEB1yP0wAyvfKKQjwpDbvufZ79I4dtjP75GzDFhxnGXT8byLqTIedlEiQP+ZXdhMnz3f36BsFGoyq5k6A6augpfYDcEPZnAp62BcAiibVWwxJCg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719941082; c=relaxed/simple; bh=DaeWz72n7Lqrk0wUaeFSzZcTmxhryhZFBe0Zlzrr9aY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=PQrRONR06B1QI9iaIQknYIOh4kujjAupDyMA66wHUDjjIZ67EnD/bpFVJ7MMfZaFp9zPPDT7nXQo7f/XfGto+jQjgI3vUN6dJsPqFsYMxVJWT4GFkfDSxgEIYecKr4Lz13wcM9hv8LHdm+Vxo/d/X+2aXnPy2I1ukdNFeqMKDAU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=yFbD5z8E; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="yFbD5z8E" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8D5F7C116B1; Tue, 2 Jul 2024 17:24:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1719941082; bh=DaeWz72n7Lqrk0wUaeFSzZcTmxhryhZFBe0Zlzrr9aY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=yFbD5z8EQ7RPeL/UPlhhsEuwQ1jLQcBy7vnw4Ix3ZX/OytufqWsYCtkejRoZIbIdL cAEeblhBd4fi7veIs3e8q7f+AsTqTqH+PT2wtCoyaVCVVr+8ShWou6TuHI5WfJcH/Z hWuCbzpPva//0Dj9+fNuYyR0SIJ5tF2eEfGJUdys= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Oleksij Rempel , Shigeru Yoshida , Marc Kleine-Budde , syzbot+5681e40d297b30f5b513@syzkaller.appspotmail.com Subject: [PATCH 6.6 122/163] net: can: j1939: Initialize unused data in j1939_send_one() Date: Tue, 2 Jul 2024 19:03:56 +0200 Message-ID: <20240702170237.670067554@linuxfoundation.org> X-Mailer: git-send-email 2.45.2 In-Reply-To: <20240702170233.048122282@linuxfoundation.org> References: <20240702170233.048122282@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shigeru Yoshida commit b7cdf1dd5d2a2d8200efd98d1893684db48fe134 upstream. syzbot reported kernel-infoleak in raw_recvmsg() [1]. j1939_send_one() creates full frame including unused data, but it doesn't initialize it. This causes the kernel-infoleak issue. Fix this by initializing unused data. [1] BUG: KMSAN: kernel-infoleak in instrument_copy_to_user include/linux/instrumented.h:114 [inline] BUG: KMSAN: kernel-infoleak in copy_to_user_iter lib/iov_iter.c:24 [inline] BUG: KMSAN: kernel-infoleak in iterate_ubuf include/linux/iov_iter.h:29 [inline] BUG: KMSAN: kernel-infoleak in iterate_and_advance2 include/linux/iov_iter.h:245 [inline] BUG: KMSAN: kernel-infoleak in iterate_and_advance include/linux/iov_iter.h:271 [inline] BUG: KMSAN: kernel-infoleak in _copy_to_iter+0x366/0x2520 lib/iov_iter.c:185 instrument_copy_to_user include/linux/instrumented.h:114 [inline] copy_to_user_iter lib/iov_iter.c:24 [inline] iterate_ubuf include/linux/iov_iter.h:29 [inline] iterate_and_advance2 include/linux/iov_iter.h:245 [inline] iterate_and_advance include/linux/iov_iter.h:271 [inline] _copy_to_iter+0x366/0x2520 lib/iov_iter.c:185 copy_to_iter include/linux/uio.h:196 [inline] memcpy_to_msg include/linux/skbuff.h:4113 [inline] raw_recvmsg+0x2b8/0x9e0 net/can/raw.c:1008 sock_recvmsg_nosec net/socket.c:1046 [inline] sock_recvmsg+0x2c4/0x340 net/socket.c:1068 ____sys_recvmsg+0x18a/0x620 net/socket.c:2803 ___sys_recvmsg+0x223/0x840 net/socket.c:2845 do_recvmmsg+0x4fc/0xfd0 net/socket.c:2939 __sys_recvmmsg net/socket.c:3018 [inline] __do_sys_recvmmsg net/socket.c:3041 [inline] __se_sys_recvmmsg net/socket.c:3034 [inline] __x64_sys_recvmmsg+0x397/0x490 net/socket.c:3034 x64_sys_call+0xf6c/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:300 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Uninit was created at: slab_post_alloc_hook mm/slub.c:3804 [inline] slab_alloc_node mm/slub.c:3845 [inline] kmem_cache_alloc_node+0x613/0xc50 mm/slub.c:3888 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:577 __alloc_skb+0x35b/0x7a0 net/core/skbuff.c:668 alloc_skb include/linux/skbuff.h:1313 [inline] alloc_skb_with_frags+0xc8/0xbf0 net/core/skbuff.c:6504 sock_alloc_send_pskb+0xa81/0xbf0 net/core/sock.c:2795 sock_alloc_send_skb include/net/sock.h:1842 [inline] j1939_sk_alloc_skb net/can/j1939/socket.c:878 [inline] j1939_sk_send_loop net/can/j1939/socket.c:1142 [inline] j1939_sk_sendmsg+0xc0a/0x2730 net/can/j1939/socket.c:1277 sock_sendmsg_nosec net/socket.c:730 [inline] __sock_sendmsg+0x30f/0x380 net/socket.c:745 ____sys_sendmsg+0x877/0xb60 net/socket.c:2584 ___sys_sendmsg+0x28d/0x3c0 net/socket.c:2638 __sys_sendmsg net/socket.c:2667 [inline] __do_sys_sendmsg net/socket.c:2676 [inline] __se_sys_sendmsg net/socket.c:2674 [inline] __x64_sys_sendmsg+0x307/0x4a0 net/socket.c:2674 x64_sys_call+0xc4b/0x3b50 arch/x86/include/generated/asm/syscalls_64.h:47 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcf/0x1e0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f Bytes 12-15 of 16 are uninitialized Memory access of size 16 starts at ffff888120969690 Data copied to user address 00000000200017c0 CPU: 1 PID: 5050 Comm: syz-executor198 Not tainted 6.9.0-rc5-syzkaller-00031-g71b1543c83d6 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 Fixes: 9d71dd0c7009 ("can: add support of SAE J1939 protocol") Reported-and-tested-by: syzbot+5681e40d297b30f5b513@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=5681e40d297b30f5b513 Acked-by: Oleksij Rempel Signed-off-by: Shigeru Yoshida Link: https://lore.kernel.org/all/20240517035953.2617090-1-syoshida@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Marc Kleine-Budde Signed-off-by: Greg Kroah-Hartman --- net/can/j1939/main.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) --- a/net/can/j1939/main.c +++ b/net/can/j1939/main.c @@ -30,10 +30,6 @@ MODULE_ALIAS("can-proto-" __stringify(CA /* CAN_HDR: #bytes before can_frame data part */ #define J1939_CAN_HDR (offsetof(struct can_frame, data)) -/* CAN_FTR: #bytes beyond data part */ -#define J1939_CAN_FTR (sizeof(struct can_frame) - J1939_CAN_HDR - \ - sizeof(((struct can_frame *)0)->data)) - /* lowest layer */ static void j1939_can_recv(struct sk_buff *iskb, void *data) { @@ -342,7 +338,7 @@ int j1939_send_one(struct j1939_priv *pr memset(cf, 0, J1939_CAN_HDR); /* make it a full can frame again */ - skb_put(skb, J1939_CAN_FTR + (8 - dlc)); + skb_put_zero(skb, 8 - dlc); canid = CAN_EFF_FLAG | (skcb->priority << 26) |