Fixing the bug of CGPT when primary entry table is invalid.

http://code.google.com/p/chromium-os/issues/detail?id=9279
This issue disclosed a bug of cgpt. The bug comes from the 'show' command always
reads the primary entry table when '-i partition' is specified. I added an
ANY_VALID constant for GetEntry to automatically select valid entry table.

Also fixed the bugs in cmd_boot.c and cmd_find.c. In cmd_add.c, stop user to
continue if any header/entry table is invalid.

Also fixed the bug that untrusted header size could cause segmentation failure.

Hungte, this is FYI. But welcome to do review.

BUG=chromium-os:9279
TEST=RUNTESTS=1 emerge-x86-generic vboot_reference
     Manually tested:
       cgpt show /tmp/test -i 1 -b
       cgpt show /tmp/test
       cgpt add /tmp/test -i 1 -l TEST
       cgpt find /tmp/test -l STATE
       cgpt boot /tmp/test -i 1

Change-Id: Iaba9c635754096a82b3ec74634af184362d4e264
Change-Id: I6f3e87e3998457676e3388d2a6ed36c0564796d8

Review URL: http://codereview.chromium.org/5115002

1 files changed, 4 insertions, 0 deletions

diff --git a/firmware/lib/cgptlib/include/cgptlib_internal.h b/firmware/lib/cgptlib/include/cgptlib_internal.h
index 66ceef13..ccd719c9 100644
--- a/firmware/lib/cgptlib/include/cgptlib_internal.h
+++ b/firmware/lib/cgptlib/include/cgptlib_internal.h
@@ -61,8 +61,12 @@
 /* alias name of index in internal array for primary and secondary header and
  * entries. */
 enum {
+  /* constants for index */
   PRIMARY = 0,
   SECONDARY = 1,
+  ANY_VALID = 9999,  /* accept any between primary and secondary */
+
+  /* constants for bit mask */
   MASK_NONE = 0,
   MASK_PRIMARY = 1,
   MASK_SECONDARY = 2,