From 28be933ce317f954be1e39a50d8f42197d6e3c15 Mon Sep 17 00:00:00 2001 From: Jim Meyering 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 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" $(am__check_post) t0250-gpt.sh.log: t0250-gpt.sh diff --git a/tests/t0205-gpt-list-clobbers-pmbr.sh b/tests/t0205-gpt-list-clobbers-pmbr.sh new file mode 100644 index 0000000..979a15e --- /dev/null +++ b/tests/t0205-gpt-list-clobbers-pmbr.sh @@ -0,0 +1,59 @@ +#!/bin/sh +# Ensure that printing a GPT partition table does not modify the pMBR. +# Due to a bug in parted-2.1, "parted /dev/... print" would do just that. +# Not a problem for most, but if you have a hybrid, e.g., gptsync'd +# GPT/MBR table, merely listing the table with Parted-2.1 would clobber +# the MBR part. + +# Copyright (C) 2010 Free Software Foundation, Inc. + +# This program is free software; you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation; either version 3 of the License, or +# (at your option) any later version. + +# This program is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. + +# You should have received a copy of the GNU General Public License +# along with this program. If not, see . + +if test "$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