Print warning when an MBR partition starts or extends past the

end of the device the MBR is currently inhabiting.

Prompted by some interesting MBR's from France, verbiage
suggestion from deraadt@, ok miod@

diff --git a/sbin/fdisk/part.c b/sbin/fdisk/part.c
index 8d279b4..d666e36 100644 (file)
--- a/sbin/fdisk/part.c
+++ b/sbin/fdisk/part.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: part.c,v 1.130 2022/05/08 18:01:23 krw Exp $  */
+/*     $OpenBSD: part.c,v 1.131 2022/08/29 07:19:14 krw Exp $  */
 
 /*
  * Copyright (c) 1997 Tobias Weingartner
@@ -422,6 +422,13 @@ PRT_print_part(const int num, const struct prt *prt, const char *units)
            start.chs_cyl, start.chs_head, start.chs_sect,
            end.chs_cyl, end.chs_head, end.chs_sect,
            prt->prt_bs, size, ut->ut_abbr, ascii_id(prt->prt_id));
+
+       if (prt->prt_bs >= DL_GETDSIZE(&dl))
+               printf("partition %d starts beyond the end of %s\n", num,
+                   disk.dk_name);
+       else if (prt->prt_bs + prt->prt_ns > DL_GETDSIZE(&dl))
+               printf("partition %d extends beyond the end of %s\n", num,
+                   disk.dk_name);
 }
 
 int