misc/vmw_vmci: fix an infoleak in vmci_host_do_receive_datagram()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: misc/vmw_vmci: fix an infoleak in vmci_host_do_receive_datagram() `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.

References

• https://git.kernel.org/stable/c/7ccf7229b96fadc3a185d1391f814a604c7ef609
• https://git.kernel.org/stable/c/f04586c2315cfd03d72ad0395705435e7ed07b1a
• https://git.kernel.org/stable/c/5a275528025ae4bc7e2232866856dfebf84b2fad
• https://git.kernel.org/stable/c/e7061dd1fef2dfb6458cd521aef27aa66f510d31
• https://git.kernel.org/stable/c/62634b43d3c4e1bf62fd540196f7081bf0885c0a
• https://git.kernel.org/stable/c/8e2f33c598370bcf828bab4d667d1d38bcd3c57d
• https://git.kernel.org/stable/c/76c50d77b928a33e5290aaa9fdc10e88254ff8c7
• https://git.kernel.org/stable/c/e5b0d06d9b10f5f43101bd6598b076c347f9295f