Commit 6daf076b authored by Kees Cook's avatar Kees Cook Committed by Shuah Khan
Browse files

selftests: splice: Adjust for handler fallback removal 



Some pseudo-filesystems do not have an explicit splice fops since adding
commit 36e2c742 ("fs: don't allow splice read/write without explicit ops"),
and now will reject attempts to use splice() in those filesystem paths.

Reported-by: default avatarkernel test robot <rong.a.chen@intel.com>
Link: https://lore.kernel.org/lkml/202009181443.C2179FB@keescook/


Fixes: 36e2c742 ("fs: don't allow splice read/write without explicit ops")
Cc: Christoph Hellwig <hch@lst.de>
Cc: Shuah Khan <shuah@kernel.org>
Cc: linux-kselftest@vger.kernel.org
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarShuah Khan <skhan@linuxfoundation.org>
parent f50688b4

tools/testing/selftests/splice/short_splice_read.sh

+98 −21
Original line number Diff line number Diff line 
#!/bin/sh

# SPDX-License-Identifier: GPL-2.0

#

# Test for mishandling of splice() on pseudofilesystems, which should catch

# bugs like 11990a5bd7e5 ("module: Correctly truncate sysfs sections output")

#

# Since splice fallback was removed as part of the set_fs() rework, many of these

# tests expect to fail now. See https://lore.kernel.org/lkml/202009181443.C2179FB@keescook/

set -e



DIR=$(dirname "$0")



ret=0



expect_success()

{

	title="$1"

	shift



	echo "" >&2

	echo "$title ..." >&2



	set +e

	"$@"

	rc=$?

	set -e



	case "$rc" in

	0)

		echo "ok: $title succeeded" >&2

		;;

	1)

		echo "FAIL: $title should work" >&2

		ret=$(( ret + 1 ))

		;;

	*)

		echo "FAIL: something else went wrong" >&2

		ret=$(( ret + 1 ))

		;;

	esac

}



expect_failure()

{

	title="$1"

	shift



	echo "" >&2

	echo "$title ..." >&2



	set +e

	"$@"

	rc=$?

	set -e



	case "$rc" in

	0)

		echo "FAIL: $title unexpectedly worked" >&2

		ret=$(( ret + 1 ))

		;;

	1)

		echo "ok: $title correctly failed" >&2

		;;

	*)

		echo "FAIL: something else went wrong" >&2

		ret=$(( ret + 1 ))

		;;

	esac

}



do_splice()

{

	filename="$1"

	bytes="$2"

	expected="$3"

	report="$4"



	out=$(./splice_read "$filename" "$bytes" | cat)

	out=$("$DIR"/splice_read "$filename" "$bytes" | cat)

	if [ "$out" = "$expected" ] ; then

		echo "ok: $filename $bytes"

		echo "      matched $report" >&2

		return 0

	else

		echo "FAIL: $filename $bytes"

		ret=1

		echo "      no match: '$out' vs $report" >&2

		return 1

	fi

}
@@ -23,34 +89,45 @@ test_splice() 
{

	filename="$1"



	echo "  checking $filename ..." >&2



	full=$(cat "$filename")

	rc=$?

	if [ $rc -ne 0 ] ; then

		return 2

	fi



	two=$(echo "$full" | grep -m1 . | cut -c-2)



	# Make sure full splice has the same contents as a standard read.

	do_splice "$filename" 4096 "$full"

	echo "    splicing 4096 bytes ..." >&2

	if ! do_splice "$filename" 4096 "$full" "full read" ; then

		return 1

	fi



	# Make sure a partial splice see the first two characters.

	do_splice "$filename" 2 "$two"

	echo "    splicing 2 bytes ..." >&2

	if ! do_splice "$filename" 2 "$two" "'$two'" ; then

		return 1

	fi



	return 0

}



# proc_single_open(), seq_read()

test_splice /proc/$$/limits

# special open, seq_read()

test_splice /proc/$$/comm

### /proc/$pid/ has no splice interface; these should all fail.

expect_failure "proc_single_open(), seq_read() splice" test_splice /proc/$$/limits

expect_failure "special open(), seq_read() splice" test_splice /proc/$$/comm



# proc_handler, proc_dointvec_minmax

test_splice /proc/sys/fs/nr_open

# proc_handler, proc_dostring

test_splice /proc/sys/kernel/modprobe

# proc_handler, special read

test_splice /proc/sys/kernel/version

### /proc/sys/ has a splice interface; these should all succeed.

expect_success "proc_handler: proc_dointvec_minmax() splice" test_splice /proc/sys/fs/nr_open

expect_success "proc_handler: proc_dostring() splice" test_splice /proc/sys/kernel/modprobe

expect_success "proc_handler: special read splice" test_splice /proc/sys/kernel/version



### /sys/ has no splice interface; these should all fail.

if ! [ -d /sys/module/test_module/sections ] ; then

	modprobe test_module

	expect_success "test_module kernel module load" modprobe test_module

fi

# kernfs, attr

test_splice /sys/module/test_module/coresize

# kernfs, binattr

test_splice /sys/module/test_module/sections/.init.text

expect_failure "kernfs attr splice" test_splice /sys/module/test_module/coresize

expect_failure "kernfs binattr splice" test_splice /sys/module/test_module/sections/.init.text



exit $ret