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

[Hou Tao <houtao1@huawei.com>]

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

 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