Changeset 40754 in vbox for trunk/src/VBox/Devices/PC/BIOS-new

Timestamp:

Apr 3, 2012 10:59:59 AM (13 years ago)

Author:

vboxsync

Message:

BIOS: Do a basic sanity check on floppy boot sectors, too.

File:

• trunk/src/VBox/Devices/PC/BIOS-new/boot.c (modified) (2 diffs)

trunk/src/VBox/Devices/PC/BIOS-new/boot.c

@@ -297 +297 @@
     }
     
-    // Don't check boot sectors on floppies and don't read CMOS - byte
-    // 0x38 in CMOS always has the low bit clear.
-    // There is *no* requirement whatsoever for a valid boot sector to
-    // have a 55AAh signature. UNIX boot floppies typically have no such
+    // There is *no* requirement whatsoever for a valid floppy boot sector
+    // to have a 55AAh signature. UNIX boot floppies typically have no such
     // signature. In general, it is impossible to tell a valid bootsector
     // from an invalid one.
@@ -317 +315 @@
 #endif // BX_ELTORITO_BOOT
     
-    if (bootchk == 0) {
-        if (read_word(bootseg,0x1fe) != 0xaa55 ||
-            read_word(bootseg,0) == read_word(bootseg,2)) {
-            print_boot_failure(bootcd, bootlan, bootdrv, 0, lastdrive);
-            return 0x00000000;
-        }
+    if (read_word(bootseg,0) == read_word(bootseg,2)
+      || (bootchk == 0 && read_word(bootseg,0x1fe) != 0xaa55))
+    {
+        print_boot_failure(bootcd, bootlan, bootdrv, 0, lastdrive);
+        return 0x00000000;
     }