Fixed assert in vhost_user_set_mem_table_postcopy

The current vhost_user_set_mem_table_postcopy() implementation
populates each region of the VHOST_USER_SET_MEM_TABLE message without
first checking if there are more than VHOST_MEMORY_MAX_NREGIONS already
populated. This can cause memory corruption if too many regions are
added to the message during the postcopy step.

This change moves an existing assert up such that attempting to
construct a VHOST_USER_SET_MEM_TABLE message with too many memory
regions will gracefully bring down qemu instead of corrupting memory.

Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Peter Turschmid <peter.turschm@nutanix.com>
Message-Id: <1579143426-18305-2-git-send-email-raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This commit is contained in:
Raphael Norwitz 2020-01-15 21:57:04 -05:00 committed by Michael S. Tsirkin
parent 67b3965e89
commit b844a4c77b

View File

@ -443,6 +443,7 @@ static int vhost_user_set_mem_table_postcopy(struct vhost_dev *dev,
&offset);
fd = memory_region_get_fd(mr);
if (fd > 0) {
assert(fd_num < VHOST_MEMORY_MAX_NREGIONS);
trace_vhost_user_set_mem_table_withfd(fd_num, mr->name,
reg->memory_size,
reg->guest_phys_addr,
@ -455,7 +456,6 @@ static int vhost_user_set_mem_table_postcopy(struct vhost_dev *dev,
msg.payload.memory.regions[fd_num].guest_phys_addr =
reg->guest_phys_addr;
msg.payload.memory.regions[fd_num].mmap_offset = offset;
assert(fd_num < VHOST_MEMORY_MAX_NREGIONS);
fds[fd_num++] = fd;
} else {
u->region_rb_offset[i] = 0;