parted/parted-2.1-gpt-clobber-pmbr-rh563211.patch

From 28be933ce317f954be1e39a50d8f42197d6e3c15 Mon Sep 17 00:00:00 2001
From: Jim Meyering <meyering@redhat.com>
Date: Sun, 7 Feb 2010 20:31:11 +0100
Subject: [PATCH parted 01/10] gpt: read-only operation could clobber MBR part of hybrid GPT+MBR table

* libparted/labels/gpt.c (gpt_read): Fix a bug introduced by me in
commit 7f753b1b, "gpt: rewrite GPT header-reading code".
Set write_back=0 in one more code path.
* tests/Makefile.am (TESTS): Add t0205-gpt-list-clobbers-pmbr.sh.
* tests/t0205-gpt-list-clobbers-pmbr.sh: New test.
Reported by aix27249 in
http://parted.alioth.debian.org/cgi-bin/trac.cgi/ticket/250
---
 libparted/labels/gpt.c                |   10 ++++--
 tests/Makefile.am                     |    1 +
 tests/t0205-gpt-list-clobbers-pmbr.sh |   59 +++++++++++++++++++++++++++++++++
 4 files changed, 72 insertions(+), 3 deletions(-)
 create mode 100644 tests/t0205-gpt-list-clobbers-pmbr.sh

diff --git a/libparted/labels/gpt.c b/libparted/labels/gpt.c
index 9d9876c..ea96a3b 100644
--- a/libparted/labels/gpt.c
+++ b/libparted/labels/gpt.c
@@ -4,7 +4,7 @@
     original version by Matt Domsch <Matt_Domsch@dell.com>
     Disclaimed into the Public Domain
 
-    Portions Copyright (C) 2001-2003, 2005-2009 Free Software Foundation, Inc.
+    Portions Copyright (C) 2001-2003, 2005-2010 Free Software Foundation, Inc.
 
     EFI GUID Partition Table handling
     Per Intel EFI Specification v1.02
@@ -932,9 +932,9 @@ gpt_read (PedDisk *disk)
   if (primary_gpt && backup_gpt)
     {
       /* Both are valid.  */
+#ifndef DISCOVER_ONLY
       if (PED_LE64_TO_CPU (primary_gpt->AlternateLBA) < disk->dev->length - 1)
         {
-#ifndef DISCOVER_ONLY
           switch (ped_exception_throw
                   (PED_EXCEPTION_ERROR,
                    (PED_EXCEPTION_FIX | PED_EXCEPTION_CANCEL
@@ -954,8 +954,12 @@ gpt_read (PedDisk *disk)
               write_back = 0;
               break;
             }
-#endif /* !DISCOVER_ONLY */
         }
+      else
+	{
+	  write_back = 0;
+	}
+#endif /* !DISCOVER_ONLY */
       gpt = primary_gpt;
       pth_free (backup_gpt);
     }
diff --git a/tests/Makefile.am b/tests/Makefile.am
index 7bfb22e..38922f6 100644
--- a/tests/Makefile.in
+++ b/tests/Makefile.in
@@ -9,6 +9,7 @@ TESTS = \
   t0200-gpt.sh \
   t0201-gpt.sh \
   t0202-gpt-pmbr.sh \
+  t0205-gpt-list-clobbers-pmbr.sh \
   t0220-gpt-msftres.sh \
   t0250-gpt.sh \
   t0280-gpt-corrupt.sh \
@@ -1261,6 +1261,8 @@ t0201-gpt.sh.log: t0201-gpt.sh
 	@p='t0201-gpt.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
 t0202-gpt-pmbr.sh.log: t0202-gpt-pmbr.sh
 	@p='t0202-gpt-pmbr.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
+t0205-gpt-list-clobbers-pmbr.sh.log: t0205-gpt-list-clobbers-pmbr.sh
+	@p='t0205-gpt-list-clobbers-pmbr.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
 t0220-gpt-msftres.sh.log: t0220-gpt-msftres.sh
 	@p='t0220-gpt-msftres.sh'; $(am__check_pre) $(LOG_COMPILE) "$$tst" $(am__check_post)
 t0250-gpt.sh.log: t0250-gpt.sh
diff --git a/tests/t0205-gpt-list-clobbers-pmbr.sh b/tests/t0205-gpt-list-clobbers-pmbr.sh
new file mode 100644
index 0000000..979a15e
--- /dev/null
+++ b/tests/t0205-gpt-list-clobbers-pmbr.sh
@@ -0,0 +1,59 @@
+#!/bin/sh
+# Ensure that printing a GPT partition table does not modify the pMBR.
+# Due to a bug in parted-2.1, "parted /dev/... print" would do just that.
+# Not a problem for most, but if you have a hybrid, e.g., gptsync'd
+# GPT/MBR table, merely listing the table with Parted-2.1 would clobber
+# the MBR part.
+
+# Copyright (C) 2010 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+if test "$VERBOSE" = yes; then
+  set -x
+  parted --version
+fi
+
+: ${srcdir=.}
+. $srcdir/t-lib.sh
+
+fail=0
+
+ss=$sector_size_
+n_sectors=400
+dev=dev-file
+
+dd if=/dev/null of=$dev bs=$ss seek=$n_sectors || fail=1
+parted -s $dev mklabel gpt                     || fail=1
+parted -s $dev mkpart p1 101s 150s             || fail=1
+parted -s $dev mkpart p2 151s 200s             || fail=1
+parted -s $dev mkpart p3 201s 250s             || fail=1
+
+parted -m -s $dev u s p                        || fail=1
+
+# Write non-NUL bytes all over the MBR, so we're likely to see any change.
+# However, be careful to leave the type of the first partition, 0xEE,
+# as well as the final two magic bytes.
+printf '%0450d\xee%059d\x55\xaa' 0 0 | dd of=$dev count=1 conv=notrunc || fail=1
+
+dd if=$dev of=before count=1 || fail=1
+
+chmod a-w $dev
+parted -m -s $dev u s p || fail=1
+
+dd if=$dev of=after count=1 || fail=1
+
+cmp before after || fail=1
+
+Exit $fail
-- 
1.6.6