Changeset 40754 in vbox

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.

Location:

trunk/src/VBox/Devices/PC

Files:

• BIOS-new/boot.c (modified) (2 diffs)
• BIOS/rombios.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;
     }
     

trunk/src/VBox/Devices/PC/BIOS/rombios.c

@@ -8717 +8717 @@
 
 #ifdef VBOX
-  // 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.
@@ -8745 +8743 @@
 #endif // BX_ELTORITO_BOOT
 
-  if (bootchk == 0) {
-    if (read_word(bootseg,0x1fe) != 0xaa55 ||
-        read_word(bootseg,0) == read_word(bootseg,2)) {
+  if (read_word(bootseg,0) == read_word(bootseg,2)
+    || (bootchk == 0 && read_word(bootseg,0x1fe) != 0xaa55))
+  {
 #ifdef VBOX
-      print_boot_failure(bootcd, bootlan, bootdrv, 0, lastdrive);
+    print_boot_failure(bootcd, bootlan, bootdrv, 0, lastdrive);
 #else /* !VBOX */
-      print_boot_failure(bootcd, bootdrv, 0, lastdrive);
+    print_boot_failure(bootcd, bootdrv, 0, lastdrive);
 #endif /* VBOX */
-      return 0x00000000;
-      }
-    }
+    return 0x00000000;
+  }
 
 #if BX_ELTORITO_BOOT