H. Peter Anvin wrote: > On 01/23/2012 10:22 AM, Phillip Susi wrote: >> >> I think the enforcement needs to stay the way it is. GPT enforces its >> limit, and arch/linux.c assumes that the limit the partition table >> advertises is actual and correct. If that isn't the case, then linux.c >> and anyone else asking the pt for its limit probably needs refactored to >> not do so. Advertising a limit that isn't actually a limit is wrong. >> >> If you want to raise the limit to 256 or even higher then you could have >> more than 256 partitions on msdos, even though it isn't supported on linux. >> >> Theoretically linux.c should then throw an exception complaining if the >> partition count exceeds that supported by the kernel, though I'm not >> sure fixing that is particularly important since parted has gone this >> long without complaining if you exceeded the old limit of 16, and now >> the limit is 256 it is even less of an issue. > > GPT enforces its limit because *that's how many slots there are in the > partition table* (by the way, you *do* handle GPT partition tables with > more than 128 slots, right?) > > Newer Linux kernel s have an overflow system which is at least supposed > to allow for additional partitions without problems; if that is broken > then that is a kernel bug, and playing games in parted will just make it > harder to diagnose and fix.
To my dismay, parted could not even create a 100-partition GPT table. But it was quick/easy to fix. With the following, it can do 128. However, considering that we hard-code the de-facto standard value of "128" in the GPT header, currently there is no way to write GPT tables with a different number of partition table entries. >From 4b61aedfb63cc97b405649f7261feb54cfdcdbfa Mon Sep 17 00:00:00 2001 From: Jim Meyering <[email protected]> Date: Mon, 23 Jan 2012 19:55:39 +0100 Subject: [PATCH 1/2] libparted: gpt: avoid invalid free with many (~100) partitions * parted/parted.c (do_print): Remove invalid free. Bug introduced via v1.8.8.1-19-gb56d69c. * NEWS (Bug fixes): Mention this. --- NEWS | 3 +++ parted/parted.c | 1 - 2 files changed, 3 insertions(+), 1 deletions(-) diff --git a/NEWS b/NEWS index 9d189dc..484034b 100644 --- a/NEWS +++ b/NEWS @@ -10,6 +10,9 @@ GNU parted NEWS -*- outline -*- ** Bug fixes + libparted: avoid an invalid free when creating many partitions in + a GPT partition table. [bug introduced in parted-1.9.0] + The msdos partition table claimed a maximum partition count of 16 but would allow you to go beyond that. This resulted in the kernel not being informed of those partitions. Corrected to enforce the diff --git a/parted/parted.c b/parted/parted.c index 96f9c34..02c5fdb 100644 --- a/parted/parted.c +++ b/parted/parted.c @@ -1171,7 +1171,6 @@ do_print (PedDevice** dev) //PED_ASSERT (row.cols == caption.cols) table_add_row_from_strlist (table, row); str_list_destroy (row); - free (tmp); free (start); free (end); free (size); -- 1.7.9.rc2.2.g183d6 >From 5b6fa1a471d2e4bf6c6ad9e2c0a1b01c4f185164 Mon Sep 17 00:00:00 2001 From: Jim Meyering <[email protected]> Date: Mon, 23 Jan 2012 20:01:30 +0100 Subject: [PATCH 2/2] tests: exercise today's bug fix, creating a GPT table with 128 entries * tests/t0212-gpt-many-partitions.sh: New test. * tests/Makefile.am (TESTS): Add it. --- tests/Makefile.am | 1 + tests/t0212-gpt-many-partitions.sh | 48 ++++++++++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+), 0 deletions(-) create mode 100644 tests/t0212-gpt-many-partitions.sh diff --git a/tests/Makefile.am b/tests/Makefile.am index 88efbdd..17486e2 100644 --- a/tests/Makefile.am +++ b/tests/Makefile.am @@ -22,6 +22,7 @@ TESTS = \ t0208-mkpart-end-in-IEC.sh \ t0210-gpt-resized-partition-entry-array.sh \ t0211-gpt-rewrite-header.sh \ + t0212-gpt-many-partitions.sh \ t0220-gpt-msftres.sh \ t0250-gpt.sh \ t0280-gpt-corrupt.sh \ diff --git a/tests/t0212-gpt-many-partitions.sh b/tests/t0212-gpt-many-partitions.sh new file mode 100644 index 0000000..b33cd5a --- /dev/null +++ b/tests/t0212-gpt-many-partitions.sh @@ -0,0 +1,48 @@ +#!/bin/sh +# gpt: create many partitions +# Before parted-3.1, this would provoke an invalid free. + +# Copyright (C) 2012 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/>. + +. "${srcdir=.}/init.sh"; path_prepend_ ../parted $srcdir + +ss=$sector_size_ + +ns=300 +dev=dev-file +# create a file large enough to hold a GPT partition table +dd if=/dev/null of=$dev bs=$ss seek=$ns || framework_failure + +for i in $(seq 128); do + s=$((34+i-1)) + cmd="$cmd mkpart p$i ${s}s ${s}s" +done +parted -m -a min -s $dev mklabel gpt $cmd u s p > out 2>&1 || fail=1 + +nl=' +' +exp=$(printf '%s\n' 'BYT;' "...:${ns}s:file:$ss:$ss:gpt:;")"$nl" + +for i in $(seq 128); do + s=$((34+i-1)) + exp="$exp$i:${s}s:${s}s:1s::p$i:;$nl" +done +printf %s "$exp" > exp || fail=1 + +sed '2s/^[^:]*:/...:/' out > k && mv k out +compare exp out || fail=1 + +Exit $fail -- 1.7.9.rc2.2.g183d6
