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e5b0d06d9b
`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 <stable@kernel.org>
Fixes: 06164d2b72 ("VMCI: queue pairs implementation.")
Signed-off-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Vishnu Dasa <vdasa@vmware.com>
Link: https://lore.kernel.org/r/20221104175849.2782567-1-glider@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.