Fail if C/H/S geometry is wrong. This is necessary for things that probe

for geometry.

diff --git a/memdisk/memdisk.asm b/memdisk/memdisk.asm
index 1f18ae7..053fa41 100644 (file)
--- a/memdisk/memdisk.asm
+++ b/memdisk/memdisk.asm
@@ -308,8 +308,12 @@ setup_regs:
                movzx ebx,cl            ; Sector number
                and bl,3Fh
                dec ebx                 ; Sector number is 1-based
+               cmp bx,[Sectors]
+               jae .overrun
                movzx edi,P_DH          ; Head number
                movzx eax,word [Heads]
+               cmp di,ax
+               jae .overrun
                shr cl,6
                xchg cl,ch              ; Now (E)CX <- cylinder number
                mul ecx                 ; eax <- Heads*cyl# (edx <- 0)