All of
 help / color / mirror / Atom feed
From: Alexander Potapenko <>
Subject: [PATCH] misc/vmw_vmci: fix an infoleak in vmci_host_do_receive_datagram()
Date: Fri,  4 Nov 2022 18:58:49 +0100	[thread overview]
Message-ID: <> (raw)

`struct vmci_event_qp` allocated by qp_notify_peer() contains padding,
which may carry uninitialized data to the userspace, as observed by

  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.

Fixes: 06164d2b72aa ("VMCI: queue pairs implementation.")
Signed-off-by: Alexander Potapenko <>
 drivers/misc/vmw_vmci/vmci_queue_pair.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c
index e71068f7759b3..844264e1b88cc 100644
--- a/drivers/misc/vmw_vmci/vmci_queue_pair.c
+++ b/drivers/misc/vmw_vmci/vmci_queue_pair.c
@@ -854,6 +854,7 @@ static int qp_notify_peer_local(bool attach, struct vmci_handle handle)
 	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,
@@ -1467,6 +1468,7 @@ 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,

             reply	other threads:[~2022-11-04 17:59 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-11-04 17:58 Alexander Potapenko [this message]
2022-11-07 19:46 ` [PATCH] misc/vmw_vmci: fix an infoleak in vmci_host_do_receive_datagram() Vishnu Dasa

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \ \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.