CVE-2022-49788

In the Linux kernel, the following vulnerability has been resolved:

misc/vmwvmci: fix an infoleak in vmcihostdoreceive_datagram()

struct vmci_event_qp allocated by qpnotifypeer() contains padding, which may carry uninitialized data to the userspace, as observed by KMSAN:

BUG: KMSAN: kernel-infoleak in instrumentcopytouser ./include/linux/instrumented.h:121 instrumentcopytouser ./include/linux/instrumented.h:121 copytouser+0x5f/0xb0 lib/usercopy.c:33 copytouser ./include/linux/uaccess.h:169 vmcihostdoreceivedatagram drivers/misc/vmwvmci/vmcihost.c:431 vmcihostunlockedioctl+0x33d/0x43d0 drivers/misc/vmwvmci/vmcihost.c:925 vfs_ioctl fs/ioctl.c:51 ...

Uninit was stored to memory at: kmemdup+0x74/0xb0 mm/util.c:131 dgdispatchashost drivers/misc/vmwvmci/vmcidatagram.c:271 vmcidatagramdispatch+0x4f8/0xfc0 drivers/misc/vmwvmci/vmcidatagram.c:339 qpnotifypeer+0x19a/0x290 drivers/misc/vmwvmci/vmciqueuepair.c:1479 qpbrokerattach drivers/misc/vmwvmci/vmciqueuepair.c:1662 qpbrokeralloc+0x2977/0x2f30 drivers/misc/vmwvmci/vmciqueuepair.c:1750 vmciqpbrokeralloc+0x96/0xd0 drivers/misc/vmwvmci/vmciqueuepair.c:1940 vmcihostdoallocqueuepair drivers/misc/vmwvmci/vmcihost.c:488 vmcihostunlockedioctl+0x24fd/0x43d0 drivers/misc/vmwvmci/vmci_host.c:927 ...

Local variable ev created at: qpnotifypeer+0x54/0x290 drivers/misc/vmwvmci/vmciqueuepair.c:1456 qpbrokerattach drivers/misc/vmwvmci/vmciqueuepair.c:1662 qpbrokeralloc+0x2977/0x2f30 drivers/misc/vmwvmci/vmciqueue_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 qpnotifypeer_local(), which may suffer from the same problem.