Re: [PATCH v2 1/2] generic: add test for race between listxattr and setxatr

[Chao Yu <yuchao0@huawei.com>]

On 2020/8/31 0:23, Eryu Guan wrote:
> On Sat, Aug 22, 2020 at 07:41:32PM +0800, Hou Tao wrote:
>> Add reproducer for a bug on ubifs where listxattr() copies
>> the newly created xattr names regardless of the remaining
>> buffer size, fails the assertion of used buffer size,
>> and may corrupt buffer memory.
>>
>> Signed-off-by: Hou Tao <houtao1@huawei.com>
>> ---
>> v2: accommodate f2fs by reducing the number of created xattrs for f2fs
> 
> Thanks for the test and revision! Is there a fix available for the ubifs
> bug? If so would you please mention the kernel commit ID in commit log
> as well?
> 
> Chao, would you please help check the update regarding to f2fs? Thanks!

Hi, all,

Sorry for the delay.

I've ran the test, it looks fine to f2fs, and also parameter value 'cnt=30'
is just touch upper boundary of xattr space size. :)

Reviewed-by: Chao Yu <yuchao0@huawei.com>

Thanks,

> 
> Eryu
> 
>>
>>   tests/generic/998     | 67 +++++++++++++++++++++++++++++++++++++++++++
>>   tests/generic/998.out |  2 ++
>>   tests/generic/group   |  1 +
>>   3 files changed, 70 insertions(+)
>>   create mode 100644 tests/generic/998
>>   create mode 100644 tests/generic/998.out
>>
>> diff --git a/tests/generic/998 b/tests/generic/998
>> new file mode 100644
>> index 00000000..26a5b620
>> --- /dev/null
>> +++ b/tests/generic/998
>> @@ -0,0 +1,67 @@
>> +#! /bin/bash
>> +# SPDX-License-Identifier: GPL-2.0
>> +# Copyright (c) 2020 Huawei. All Rights Reserved.
>> +#
>> +# FS QA Test 998
>> +#
>> +# Test race between listxattr() and setxattr(). It reproduces a bug
>> +# on UBIFS where listxattr() copies the newly created xattr names
>> +# regardless of the remaining buffer size, fails the assertion of
>> +# used buffer size, and may corrupt buffer memory.
>> +#
>> +seq=`basename $0`
>> +seqres=$RESULT_DIR/$seq
>> +echo "QA output created by $seq"
>> +
>> +here=`pwd`
>> +tmp=/tmp/$$
>> +status=1	# failure is the default!
>> +trap "_cleanup; exit \$status" 0 1 2 3 15
>> +
>> +_cleanup()
>> +{
>> +	cd /
>> +	rm -f $tmp.*
>> +	rm -f $TEST_DIR/$seq
>> +}
>> +
>> +# get standard environment, filters and checks
>> +. ./common/rc
>> +. ./common/attr
>> +
>> +# remove previous $seqres.full before test
>> +rm -f $seqres.full
>> +
>> +# real QA test starts here
>> +_supported_fs generic
>> +_supported_os Linux
>> +_require_attrs
>> +
>> +target=$TEST_DIR/$seq
>> +touch $target
>> +
>> +# start a background listxattr
>> +runfile="$tmp.listxattr"
>> +touch $runfile
>> +while [ -e $runfile ]; do
>> +	${GETFATTR_PROG} $target >/dev/null 2>&1
>> +done &
>> +
>> +# add new xattr continuously
>> +largename=`for i in $(seq 0 128); do echo -n a; done`
>> +cnt=100
>> +# f2fs has limited spaces for xattr
>> +[ $FSTYP == "f2fs" ] && cnt=30
>> +for i in $(seq 1 $cnt); do
>> +	${SETFATTR_PROG} -n user.${largename}.$i -v $i $target
>> +done
>> +
>> +rm -f $runfile
>> +wait > /dev/null 2>&1
>> +rm -f $target
>> +
>> +echo Silence is golden
>> +
>> +# success, all done
>> +status=0
>> +exit
>> diff --git a/tests/generic/998.out b/tests/generic/998.out
>> new file mode 100644
>> index 00000000..d2679ae0
>> --- /dev/null
>> +++ b/tests/generic/998.out
>> @@ -0,0 +1,2 @@
>> +QA output created by 998
>> +Silence is golden
>> diff --git a/tests/generic/group b/tests/generic/group
>> index d9ab9a31..62697ac5 100644
>> --- a/tests/generic/group
>> +++ b/tests/generic/group
>> @@ -605,3 +605,4 @@
>>   600 auto quick quota
>>   601 auto quick quota
>>   602 auto quick encrypt
>> +998 auto quick attr
>> -- 
>> 2.25.0.4.g0ad7144999
> .
>