Hi Zorro:
On 2022/9/3 17:57, Zorro Lang wrote:
On Sat, Sep 03, 2022 at 11:51:13AM +0800, Guo Xuenan wrote:
Hi Zorro：
On 2022/9/3 9:39, Zorro Lang wrote:
On Fri, Sep 02, 2022 at 05:40:46PM +0800, Guo Xuenan wrote:
Test leaf dir allocting new block when bestfree array size
less than data blocks count, which may lead to UAF.
Signed-off-by: Guo Xuenan <guoxuenan@xxxxxxxxxx>
---
tests/xfs/554 | 48 +++++++++++++++++++++++++++++++++++++++++++++++
tests/xfs/554.out | 6 ++++++
2 files changed, 54 insertions(+)
create mode 100755 tests/xfs/554
create mode 100644 tests/xfs/554.out
diff --git a/tests/xfs/554 b/tests/xfs/554
new file mode 100755
index 00000000..fcf45731
--- /dev/null
+++ b/tests/xfs/554
@@ -0,0 +1,48 @@
+#! /bin/bash
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (c) 2022 Huawei Limited. All Rights Reserved.
+#
+# FS QA Test No. 554
+#
+# Test leaf dir bestfree array size match with dir disk size
Is it for a known bug? known commit id?
The bug is being solved and waitting to be reviewed here[v1/v2].
[v1]
https://lore.kernel.org/all/20220902094046.3891252-1-guoxuenan@xxxxxxxxxx/
[v2]
https://lore.kernel.org/all/20220831121639.3060527-1-guoxuenan@xxxxxxxxxx/
+#
+. ./common/preamble
+_begin_fstest auto quick
+
+# Import common functions.
+. ./common/populate
+
+# real QA test starts here
+_supported_fs xfs
+_require_scratch
Do you need V5 xfs? Or v4 is fine?
_require_scratch_xfs_crc ??
Both v4 and v5 have this problem,
+_require_check_dmesg
+
+echo "Format and mount"
+_scratch_mkfs > $seqres.full 2>&1
+_scratch_mount >> $seqres.full 2>&1
If _scratch_mount fails, the testing will exit directly, so generally we just
run _scratch_mount.
OK, you are right.
+
+echo "Create and check leaf dir"
+blksz="$(stat -f -c '%s' "${SCRATCH_MNT}")"
+dblksz="$($XFS_INFO_PROG "${SCRATCH_DEV}" | grep naming.*bsize | sed -e 's/^.*bsize=//g' -e 's/\([0-9]*\).*$/\1/g')"
Why do you need these two kinds of block size for xfs? And you sometimes
use the former, sometimes use the later? If you'd like to get the xfs data
block size, you can:
_scratch_mkfs | _filter_mkfs >>$seqres.full 2>$tmp.mkfs
. $tmp.mkfs
Then "dbsize" is what you want.
+leaf_lblk="$((32 * 1073741824 / blksz))"
+node_lblk="$((64 * 1073741824 / blksz))"
I didn't see the "node_lblk" is used in this case, looks like you don't want to
get directory node blocks in this case.
It's really needed here, must define leaf_lblk and node_lblk before calling
__populate_check_xfs_dir
or an waring will be printed by the function.
Oh, so these two global parameters are used for later __populate_check_xfs_dir.
Hmm.. are "blksz" and "dblksz" necessary too, for someone __populate_* helper
you used? I really don't understand why we need them both. These helpers are
written by Darrick, I think he learns about that more :)
yes, there are same usage for eg. xfs/113 xfs/101 ...
+__populate_create_dir "${SCRATCH_MNT}/S_IFDIR.FMT_LEAF" "$((dblksz / 12))"
+leaf_dir="$(__populate_find_inode "${SCRATCH_MNT}/S_IFDIR.FMT_LEAF")"
+_scratch_unmount
+__populate_check_xfs_dir "${leaf_dir}" "leaf"
+
+echo "Inject bad bestfress array size"
+_scratch_xfs_db -x -c "inode ${leaf_dir}" -c "dblock 8388608" -c "write ltail.bestcount 0"
As you tried to detect xfs block size above, so it might not 4k block size, so
8388608 is not fixed.
According to the kernel definition:
#define XFS_DIR2_DATA_ALIGN_LOG 3
#define XFS_DIR2_SPACE_SIZE (1ULL << (32 + XFS_DIR2_DATA_ALIGN_LOG))
#define XFS_DIR2_LEAF_SPACE 1
#define XFS_DIR2_LEAF_OFFSET (XFS_DIR2_LEAF_SPACE * XFS_DIR2_SPACE_SIZE)
The XFS_DIR2_LEAF_OFFSET = 1 * (1 << (32 + 3)) = 1<<35 = 34359738368 = 32GB, so
the fixed logical offset of leaf extent is 34359738368 bytes, then the offset
block number should be "34359738368 / dbsize". 8388608 is only for 4k block
size.
Sorry, you are totally right! it should be "dblock ${leaf_lblk}"
That looks better.
+
+echo "Test add entry to dir"
+_scratch_mount
+touch ${SCRATCH_MNT}/S_IFDIR.FMT_LEAF/{1..100}.txt > /dev/null 2>&1
+_scratch_unmount 2>&1
This "2>&1" looks useless, I think it can be removed
OK, in v2 it will disappear :）
+_repair_scratch_fs >> $seqres.full 2>&1
Can you explain more about this testing steps? The xfs has been corrupted, then
we expect is can be mounted. And create 100 new files on that corrupted dir,
do you expect the 100 files can be created successfully? Or what ever, even
nothing be created?
since we have create an leaf dir,and set bestfree count to 0; then, need to
touch some files to
trigger the problem, the action will be failed as expected.
OK, I think you can add more comments to explain this part. Due to you make
a obvious corruption at first, then try to mount and write the corrupted fs,
there must be some error happen, so you'd better to explain what do you
expect, and what's not.
Thanks a lot, and I'm happliy accept your suggestion, It's really a bit
confusing here,
I will add some specific description
What's the xfs_repair expect? Fix all curruption and left a clean xfs?
Adding repair is really not necessary, only toavoid _check_xfs_filesystem
warning
" _check_xfs_filesystem: filesystem on /dev/sdb is inconsistent (r)"
Except you'd like to verify if xfs_repair can fix this corruption. Or replace
_require_scatch with _require_scratch_nocheck, that will help you avoid known
fs corruption warning. Then you can remove _repair_scratch_fs and above
_scratch_unmount.
Yep, you got my point, since it's my fisrt contribution code for
fstests, and
I didn't figure out how to disable the post fsck execution. so great, I
will
add _require_scratch_nocheck.
+
+# check demsg error
+_check_dmesg
Which above step will trigger a dmesg you want to check? What kind of dmesg do
dmesg eg:
[ 80.543884] XFS (sdb): Internal error xfs_dir2_data_use_free at line 1200
of file fs/xfs/libxfs/xfs_dir2_data.c. Caller
xfs_dir2_data_use_free+0xb3/0xeb0
[ 80.545141] CPU: 2 PID: 2978 Comm: touch Not tainted 6.0.0-rc3+ #115
[ 80.545715] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
[ 80.546546] Call Trace:
[ 80.546785] <TASK>
[ 80.546985] dump_stack_lvl+0x4d/0x66
[ 80.547335] xfs_corruption_error+0x132/0x150
[ 80.548391] ? xfs_dir2_data_use_free+0xb3/0xeb0
[ 80.548901] ? xfs_dir2_data_use_free+0xb3/0xeb0
[ 80.549319] ? xfs_dir2_data_use_free+0xb3/0xeb0
[ 80.550190] xfs_dir2_data_use_free+0x198/0xeb0
[ 80.550718] ? xfs_dir2_data_use_free+0xb3/0xeb0
[ 80.551140] xfs_dir2_leaf_addname+0xa59/0x1ac0
[ 80.551881] ? _raw_spin_unlock_irqrestore+0x42/0x80
[ 80.552403] ? xfs_dir2_leaf_search_hash+0x300/0x300
or
[ 201.405239] BUG: KASAN: slab-out-of-bounds in
xfs_dir2_leaf_addname+0x1995/0x1ac0
[ 201.406179] Write of size 2 at addr ffff888078c33000 by task touch/7433
[ 201.407010]
[ 201.407217] CPU: 6 PID: 7433 Comm: touch Not tainted 6.0.0-rc3+ #115
[ 201.408016] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
[ 201.409143] Call Trace:
[ 201.409461] <TASK>
[ 201.409740] dump_stack_lvl+0x4d/0x66
[ 201.410214] print_report.cold+0xf6/0x691
[ 201.410730] ? xfs_dir3_data_init+0x18e/0x960
UAF/slab-out-of bound etc...
Look at the _check_dmesg, it checks "Internal error" and "\bBUG:" etc, so I
think it can catch above dmesg error, you can remove this _check_dmesg and
run again, to make sure if it works as you wish.
OK, I will check it again.
you want to check? I think xfstests checks dmesg at the end of each test case,
except you need to check some special one, or need a special filter?
check demsg without filter seems enough, so i did not add special filter.
Thanks,
Zorro
+
+# success, all done
+status=0
+exit
diff --git a/tests/xfs/554.out b/tests/xfs/554.out
new file mode 100644
index 00000000..ea1f30cc
--- /dev/null
+++ b/tests/xfs/554.out
@@ -0,0 +1,6 @@
+QA output created by 554
+Format and mount
+Create and check leaf dir
+Inject bad bestfress array size
+ltail.bestcount = 0
+Test add entry to dir
--
2.25.1
.
.
Thanks
Xuenan
