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libvhost-user: Add vu_rem_mem_reg input validation

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Today if multiple FDs are sent from the VMM to the backend in a
VHOST_USER_REM_MEM_REG message, one FD will be unmapped and the remaining
FDs will be leaked. Therefore if multiple FDs are sent we report an
error and fail the operation, closing all FDs in the message.

Likewise in case the VMM sends a message with a size less than that of a
memory region descriptor, we add a check to gracefully report an error
and fail the operation rather than crashing.

Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20220117041050.19718-2-raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
This commit is contained in:
Raphael Norwitz 2022-01-17 04:12:24 +00:00 committed by Michael S. Tsirkin
parent 408ca92634
commit 316ee11144
2 changed files with 17 additions and 0 deletions
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15
subprojects/libvhost-user/libvhost-user.c
View File

@ -801,6 +801,21 @@ vu_rem_mem_reg(VuDev *dev, VhostUserMsg *vmsg) {
VuDevRegion shadow_regions[VHOST_USER_MAX_RAM_SLOTS] = {};
VhostUserMemoryRegion m = vmsg->payload.memreg.region, *msg_region = &m;
if (vmsg->fd_num != 1) {
vmsg_close_fds(vmsg);
vu_panic(dev, "VHOST_USER_REM_MEM_REG received %d fds - only 1 fd "
"should be sent for this message type", vmsg->fd_num);
return false;
}
if (vmsg->size < VHOST_USER_MEM_REG_SIZE) {
close(vmsg->fds[0]);
vu_panic(dev, "VHOST_USER_REM_MEM_REG requires a message size of at "
"least %d bytes and only %d bytes were received",
VHOST_USER_MEM_REG_SIZE, vmsg->size);
return false;
}
DPRINT("Removing region:\n");
DPRINT(" guest_phys_addr: 0x%016"PRIx64"\n",
msg_region->guest_phys_addr);

2
subprojects/libvhost-user/libvhost-user.h
View File

@ -129,6 +129,8 @@ typedef struct VhostUserMemoryRegion {
uint64_t mmap_offset;
} VhostUserMemoryRegion;
#define VHOST_USER_MEM_REG_SIZE (sizeof(VhostUserMemoryRegion))
typedef struct VhostUserMemory {
uint32_t nregions;
uint32_t padding;