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 98DA7C4332F for ; Wed, 23 Nov 2022 08:56:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236789AbiKWI4x (ORCPT ); Wed, 23 Nov 2022 03:56:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60382 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236807AbiKWI4k (ORCPT ); Wed, 23 Nov 2022 03:56:40 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0EDF9FFAA6 for ; Wed, 23 Nov 2022 00:56:39 -0800 (PST) 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 ams.source.kernel.org (Postfix) with ESMTPS id BB322B81EEE for ; Wed, 23 Nov 2022 08:56:37 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B30E0C433C1; Wed, 23 Nov 2022 08:56:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669193796; bh=BqmV0dlf0J2tKlVx2gqvDigoQunsxpVZJo54U8idNFY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NZLNFvr1JB1qMeD1knIoPmaZRFzma8xGQGAn5vSj5cn4hj7Qjli2nZUSK6JKbq9r9 PqyjwuJ35vbQeXGHjhL11Be5+1QjiyQhw9aJEvclTl7/4rKicpewtaTd+kUs8gptx7 yWieXB2A6KGZ9iDaiO1PKvIjJo0y2twzlc5+6s7Q= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, syzbot+39be4da489ed2493ba25@syzkaller.appspotmail.com, stable , Alexander Potapenko , Vishnu Dasa Subject: [PATCH 4.9 64/76] misc/vmw_vmci: fix an infoleak in vmci_host_do_receive_datagram() Date: Wed, 23 Nov 2022 09:51:03 +0100 Message-Id: <20221123084548.853224949@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221123084546.742331901@linuxfoundation.org> References: <20221123084546.742331901@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: Alexander Potapenko commit e5b0d06d9b10f5f43101bd6598b076c347f9295f upstream. `struct vmci_event_qp` allocated by qp_notify_peer() contains padding, which may carry uninitialized data to the userspace, as observed by KMSAN: BUG: KMSAN: kernel-infoleak in instrument_copy_to_user ./include/linux/instrumented.h:121 instrument_copy_to_user ./include/linux/instrumented.h:121 _copy_to_user+0x5f/0xb0 lib/usercopy.c:33 copy_to_user ./include/linux/uaccess.h:169 vmci_host_do_receive_datagram drivers/misc/vmw_vmci/vmci_host.c:431 vmci_host_unlocked_ioctl+0x33d/0x43d0 drivers/misc/vmw_vmci/vmci_host.c:925 vfs_ioctl fs/ioctl.c:51 ... Uninit was stored to memory at: kmemdup+0x74/0xb0 mm/util.c:131 dg_dispatch_as_host drivers/misc/vmw_vmci/vmci_datagram.c:271 vmci_datagram_dispatch+0x4f8/0xfc0 drivers/misc/vmw_vmci/vmci_datagram.c:339 qp_notify_peer+0x19a/0x290 drivers/misc/vmw_vmci/vmci_queue_pair.c:1479 qp_broker_attach drivers/misc/vmw_vmci/vmci_queue_pair.c:1662 qp_broker_alloc+0x2977/0x2f30 drivers/misc/vmw_vmci/vmci_queue_pair.c:1750 vmci_qp_broker_alloc+0x96/0xd0 drivers/misc/vmw_vmci/vmci_queue_pair.c:1940 vmci_host_do_alloc_queuepair drivers/misc/vmw_vmci/vmci_host.c:488 vmci_host_unlocked_ioctl+0x24fd/0x43d0 drivers/misc/vmw_vmci/vmci_host.c:927 ... Local variable ev created at: qp_notify_peer+0x54/0x290 drivers/misc/vmw_vmci/vmci_queue_pair.c:1456 qp_broker_attach drivers/misc/vmw_vmci/vmci_queue_pair.c:1662 qp_broker_alloc+0x2977/0x2f30 drivers/misc/vmw_vmci/vmci_queue_pair.c:1750 Bytes 28-31 of 48 are uninitialized Memory access of size 48 starts at ffff888035155e00 Data copied to user address 0000000020000100 Use memset() to prevent the infoleaks. Also speculatively fix qp_notify_peer_local(), which may suffer from the same problem. Reported-by: syzbot+39be4da489ed2493ba25@syzkaller.appspotmail.com Cc: stable Fixes: 06164d2b72aa ("VMCI: queue pairs implementation.") Signed-off-by: Alexander Potapenko Reviewed-by: Vishnu Dasa Link: https://lore.kernel.org/r/20221104175849.2782567-1-glider@google.com Signed-off-by: Greg Kroah-Hartman --- drivers/misc/vmw_vmci/vmci_queue_pair.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/misc/vmw_vmci/vmci_queue_pair.c +++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c @@ -952,6 +952,7 @@ static int qp_notify_peer_local(bool att u32 context_id = vmci_get_context_id(); struct vmci_event_qp ev; + memset(&ev, 0, sizeof(ev)); ev.msg.hdr.dst = vmci_make_handle(context_id, VMCI_EVENT_HANDLER); ev.msg.hdr.src = vmci_make_handle(VMCI_HYPERVISOR_CONTEXT_ID, VMCI_CONTEXT_RESOURCE_ID); @@ -1563,6 +1564,7 @@ static int qp_notify_peer(bool attach, * kernel. */ + memset(&ev, 0, sizeof(ev)); ev.msg.hdr.dst = vmci_make_handle(peer_id, VMCI_EVENT_HANDLER); ev.msg.hdr.src = vmci_make_handle(VMCI_HYPERVISOR_CONTEXT_ID, VMCI_CONTEXT_RESOURCE_ID);