QEMU crashes with vmware_vga when running a Linux guest with the latest
X.org vmware video driver if QEMU is using SDL for video output. In
this case, vmware_vga advertises cursor acceleration to the guest, and
the crash comes when the guest does a DEFINE_CURSOR command with a 64x64
32bpp cursor. This request overruns the image[] array in struct
vmsvga_cursor_definition_s and QEMU ends up segfaulting because of
memory corruption caused by writing past the end of the array.
Fix this by enlarging the image[] array to be able to hold 4096 32-bit
pixels so we don't fail for the case of 64*64*32bpp, and also add error
checking to avoid a crash if an even bigger request is sent by a guest.
Signed-off-by: Roland Dreier <rola...@cisco.com>
---
hw/vmware_vga.c | 11 ++++++++++-
1 files changed, 10 insertions(+), 1 deletions(-)
diff --git a/hw/vmware_vga.c b/hw/vmware_vga.c
index f3e3749..d253a2e 100644
--- a/hw/vmware_vga.c
+++ b/hw/vmware_vga.c
@@ -462,7 +462,7 @@ struct vmsvga_cursor_definition_s {
int hot_x;
int hot_y;
uint32_t mask[1024];
- uint32_t image[1024];
+ uint32_t image[4096]; /* allow for 64x64 32bpp cursor */
};
#define SVGA_BITMAP_SIZE(w, h) ((((w) + 31) >> 5) * (h))
@@ -557,6 +557,15 @@ static void vmsvga_fifo_run(struct vmsvga_state_s *s)
cursor.height = y = vmsvga_fifo_read(s);
vmsvga_fifo_read(s);
cursor.bpp = vmsvga_fifo_read(s);
+
+ if (SVGA_BITMAP_SIZE(x, y) > sizeof cursor.mask / sizeof (uint32_t)
||
+ SVGA_PIXMAP_SIZE(x, y, cursor.bpp) > sizeof cursor.image /
sizeof (uint32_t)) {
+ fprintf(stderr, "%s: DEFINE_CSURSOR too large x: %d, y: %d
bpp: %d\n",
+ __FUNCTION__, x, y, cursor.bpp);
+ args = SVGA_BITMAP_SIZE(x, y) + SVGA_PIXMAP_SIZE(x, y,
cursor.bpp);
+ goto badcmd;
+ }
+
for (args = 0; args < SVGA_BITMAP_SIZE(x, y); args ++)
cursor.mask[args] = vmsvga_fifo_read_raw(s);
for (args = 0; args < SVGA_PIXMAP_SIZE(x, y, cursor.bpp); args ++)
