Return NULL if the requested buffer size does not fit within the slot memory region.
Reported-by: Wenxu Yin (@awxylitol) Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1336 Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org> --- hw/display/qxl.c | 11 ++++++++++- hw/display/qxl.h | 2 +- 2 files changed, 11 insertions(+), 2 deletions(-) diff --git a/hw/display/qxl.c b/hw/display/qxl.c index 231d733250..e5e162f82d 100644 --- a/hw/display/qxl.c +++ b/hw/display/qxl.c @@ -1462,7 +1462,7 @@ static bool qxl_get_check_slot_offset(PCIQXLDevice *qxl, QXLPHYSICAL pqxl, void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL pqxl, int group_id, size_t size) { - uint64_t offset; + uint64_t offset, ptr_end_offset; uint32_t slot; void *ptr; @@ -1474,6 +1474,15 @@ void *qxl_phys2virt(PCIQXLDevice *qxl, QXLPHYSICAL pqxl, int group_id, if (!qxl_get_check_slot_offset(qxl, pqxl, &slot, &offset)) { return NULL; } + + ptr_end_offset = qxl->guest_slots[slot].offset + offset + size; + if (ptr_end_offset > memory_region_size(qxl->guest_slots[slot].mr)) { + qxl_set_guest_bug(qxl, + "slot %d offset %"PRIu64" size %zu: " + "overrun by %"PRIu64" bytes\n", + slot, offset, size, ptr_end_offset - offset); + return NULL; + } ptr = memory_region_get_ram_ptr(qxl->guest_slots[slot].mr); ptr += qxl->guest_slots[slot].offset; ptr += offset; diff --git a/hw/display/qxl.h b/hw/display/qxl.h index bf03138ab4..7894bd5134 100644 --- a/hw/display/qxl.h +++ b/hw/display/qxl.h @@ -157,7 +157,7 @@ OBJECT_DECLARE_SIMPLE_TYPE(PCIQXLDevice, PCI_QXL) * * Returns a host pointer to a buffer placed at offset @phys within the * active slot @group_id of the PCI VGA RAM memory region associated with - * the @qxl device. If the slot is inactive, or the offset is out + * the @qxl device. If the slot is inactive, or the offset + size are out * of the memory region, returns NULL. * * Use with care; by the time this function returns, the returned pointer is -- 2.38.1