ati-vga: Fix check for blt outside vram

Fix the check preventing calling pixman functions that would access
memory outside allocated vram. The r128 X driver sometimes seem to try
blits that span outside vram, this check prevents crashing QEMU in
that case. (The r128 X driver may have problems even on real hardware
so I'm not sure if it's a client bug or emulation problem but at least
QEMU should survive.)

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Tested-by: Andrew Randrianasulu <randrianasulu@gmail.com>
Message-Id: <20190409110732.5C5FF7465DB@zero.eik.bme.hu>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 6 insertions, 6 deletions

diff --git a/hw/display/ati_2d.c b/hw/display/ati_2d.c
index bc98ba6..fe3ae14 100644
--- a/hw/display/ati_2d.c
+++ b/hw/display/ati_2d.c
@@ -79,10 +79,10 @@ void ati_2d_blt(ATIVGAState *s)
                 s->regs.dst_width, s->regs.dst_height);
         end = s->vga.vram_ptr + s->vga.vram_size;
         if (src_bits >= end || dst_bits >= end ||
-            src_bits + (s->regs.src_y + s->regs.dst_height) * src_stride +
-            s->regs.src_x >= end ||
-            dst_bits + (s->regs.dst_y + s->regs.dst_height) * dst_stride +
-            s->regs.dst_x >= end) {
+            src_bits + s->regs.src_x + (s->regs.src_y + s->regs.dst_height) *
+            src_stride * sizeof(uint32_t) >= end ||
+            dst_bits + s->regs.dst_x + (s->regs.dst_y + s->regs.dst_height) *
+            dst_stride * sizeof(uint32_t) >= end) {
             qemu_log_mask(LOG_UNIMP, "blt outside vram not implemented\n");
             return;
         }
@@ -140,8 +140,8 @@ void ati_2d_blt(ATIVGAState *s)
                 filler);
         end = s->vga.vram_ptr + s->vga.vram_size;
         if (dst_bits >= end ||
-            dst_bits + (s->regs.dst_y + s->regs.dst_height) * dst_stride +
-            s->regs.dst_x >= end) {
+            dst_bits + s->regs.dst_x + (s->regs.dst_y + s->regs.dst_height) *
+            dst_stride * sizeof(uint32_t) >= end) {
             qemu_log_mask(LOG_UNIMP, "blt outside vram not implemented\n");
             return;
         }