[Qemu-devel] [PATCH] usbredir: fix buffer-overflow on vmload

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

If interface_count is NO_INTERFACE_INFO, let's not access the arrays
out-of-bounds.

==994==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x625000243930 at pc 0x5642068086a8 bp 0x7f0b6f9ffa50 sp 0x7f0b6f9ffa40
READ of size 1 at 0x625000243930 thread T0
    #0 0x5642068086a7 in usbredir_check_bulk_receiving /home/elmarco/src/qemu/hw/usb/redirect.c:1503
    #1 0x56420681301c in usbredir_post_load /home/elmarco/src/qemu/hw/usb/redirect.c:2154
    #2 0x5642068a56c2 in vmstate_load_state /home/elmarco/src/qemu/migration/vmstate.c:168
    #3 0x56420688e2ac in vmstate_load /home/elmarco/src/qemu/migration/savevm.c:829
    #4 0x5642068980cb in qemu_loadvm_section_start_full /home/elmarco/src/qemu/migration/savevm.c:2211
    #5 0x564206899645 in qemu_loadvm_state_main /home/elmarco/src/qemu/migration/savevm.c:2395
    #6 0x5642068998cf in qemu_loadvm_state /home/elmarco/src/qemu/migration/savevm.c:2467
    #7 0x56420685f3e9 in process_incoming_migration_co /home/elmarco/src/qemu/migration/migration.c:449
    #8 0x564207106c47 in coroutine_trampoline /home/elmarco/src/qemu/util/coroutine-ucontext.c:115
    #9 0x7f0c0604e37f  (/lib64/libc.so.6+0x4d37f)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/usb/redirect.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/usb/redirect.c b/hw/usb/redirect.c
index 998fc6e4b0..9764a57987 100644
--- a/hw/usb/redirect.c
+++ b/hw/usb/redirect.c
@@ -1495,6 +1495,11 @@ static void usbredir_check_bulk_receiving(USBRedirDevice *dev)
     for (i = EP2I(USB_DIR_IN); i < MAX_ENDPOINTS; i++) {
         dev->endpoint[i].bulk_receiving_enabled = 0;
     }
+
+    if (dev->interface_info.interface_count == NO_INTERFACE_INFO) {
+        return;
+    }
+
     for (i = 0; i < dev->interface_info.interface_count; i++) {
         quirks = usb_get_quirks(dev->device_info.vendor_id,
                                 dev->device_info.product_id,
-- 
2.23.0.rc1