Messages in this thread | | | From | Vishnu Dasa <> | Subject | Re: [PATCH] misc/vmw_vmci: fix an infoleak in vmci_host_do_receive_datagram() | Date | Mon, 7 Nov 2022 19:46:42 +0000 |
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> On Nov 4, 2022, at 10:58 AM, Alexander Potapenko <glider@google.com> wrote: > > `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. >
Thanks for the fix!
Regards, Vishnu
> Reported-by: syzbot+39be4da489ed2493ba25@syzkaller.appspotmail.com > Fixes: 06164d2b72aa ("VMCI: queue pairs implementation.") > Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Vishnu Dasa <vdasa@vmware.com>
> --- > 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, > VMCI_CONTEXT_RESOURCE_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, > VMCI_CONTEXT_RESOURCE_ID); > -- > 2.38.1.431.g37b22c650d-goog >
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