Per the VBE 2.0 specification, the VBE controller information is 512
bytes long when the "VBE2" signature is provided, instead of the
original 256 bytes.

src/bootsplash.c uses the original pre-VBE-2.0 256-byte structure while
also filling in the "VBE2" signature, so a video BIOS that makes use of
the VBE2 OemData area could write past the end of the allocated region.

The original bootsplash code did not have this bug; it was introduced
when the bootsplash VBE structures were merged with the VGA ROM struct
definitions.

Fixes: 69e941c159ed ("Merge bootsplash and VGA ROM vbe structure definitions")
Signed-off-by: Daniel Verkamp <daniel@drv.nu>
---
 src/std/vbe.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/std/vbe.h b/src/std/vbe.h
index 94b4ad86..fe96f5ec 100644
--- a/src/std/vbe.h
+++ b/src/std/vbe.h
@@ -18,6 +18,8 @@ struct vbe_info {
     struct segoff_s oem_product_string;
     struct segoff_s oem_revision_string;
     u8 reserved[222];
+    /* VBE 2.0 */
+    u8 oem_data[256];
 } PACKED;
 
 struct vbe_mode_info {
-- 
2.43.0

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