From 2ea622b887e74497ce5aac5bfe247502b5786f56 Mon Sep 17 00:00:00 2001 From: Eric Sandeen Date: Tue, 14 May 2019 15:45:10 -0700 Subject: [PATCH] tools/testing/selftests/sysctl/sysctl.sh: add proc_do_large_bitmap() test case The kernel has only two users of proc_do_large_bitmap(), the kernel CPU watchdog, and the ip_local_reserved_ports. Refer to watchdog_cpumask and ip_local_reserved_ports in Documentation for further details on these. When you input a large buffer into these, when it is larger than PAGE_SIZE- 1, the input data gets misparsed, and the user get incorrectly informed that the desired input value was set. This commit implements a test which mimics and exploits that use case, it uses a bitmap size, as in the watchdog case. The bitmap is used to test the bitmap proc handler, proc_do_large_bitmap(). The next commit fixes this issue. [akpm@linux-foundation.org: move proc_do_large_bitmap() export to EOF] [mcgrof@kernel.org: use new target description for backward compatibility] [mcgrof@kernel.org: augment test number to 50, ran into issues with bash string comparisons when testing up to 50 cases.] [mcgrof@kernel.org: introduce and use verify_diff_proc_file() to use diff] [mcgrof@kernel.org: use mktemp for tmp file] [mcgrof@kernel.org: merge shell test and C code] [mcgrof@kernel.org: commit log love] [mcgrof@kernel.org: export proc_do_large_bitmap() to allow for the test [mcgrof@kernel.org: check for the return value when writing to the proc file] Link: http://lkml.kernel.org/r/20190320222831.8243-6-mcgrof@kernel.org Signed-off-by: Eric Sandeen Signed-off-by: Luis Chamberlain Acked-by: Kees Cook Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/test_sysctl.c | 18 +++++- tools/testing/selftests/sysctl/sysctl.sh | 81 +++++++++++++++++++++++- 2 files changed, 96 insertions(+), 3 deletions(-) diff --git a/lib/test_sysctl.c b/lib/test_sysctl.c index 3dd801c1c85b..566dad3f4196 100644 --- a/lib/test_sysctl.c +++ b/lib/test_sysctl.c @@ -47,6 +47,9 @@ struct test_sysctl_data { unsigned int uint_0001; char string_0001[65]; + +#define SYSCTL_TEST_BITMAP_SIZE 65536 + unsigned long *bitmap_0001; }; static struct test_sysctl_data test_data = { @@ -102,6 +105,13 @@ static struct ctl_table test_table[] = { .mode = 0644, .proc_handler = proc_dostring, }, + { + .procname = "bitmap_0001", + .data = &test_data.bitmap_0001, + .maxlen = SYSCTL_TEST_BITMAP_SIZE, + .mode = 0644, + .proc_handler = proc_do_large_bitmap, + }, { } }; @@ -129,15 +139,21 @@ static struct ctl_table_header *test_sysctl_header; static int __init test_sysctl_init(void) { + test_data.bitmap_0001 = kzalloc(SYSCTL_TEST_BITMAP_SIZE/8, GFP_KERNEL); + if (!test_data.bitmap_0001) + return -ENOMEM; test_sysctl_header = register_sysctl_table(test_sysctl_root_table); - if (!test_sysctl_header) + if (!test_sysctl_header) { + kfree(test_data.bitmap_0001); return -ENOMEM; + } return 0; } late_initcall(test_sysctl_init); static void __exit test_sysctl_exit(void) { + kfree(test_data.bitmap_0001); if (test_sysctl_header) unregister_sysctl_table(test_sysctl_header); } diff --git a/tools/testing/selftests/sysctl/sysctl.sh b/tools/testing/selftests/sysctl/sysctl.sh index 4eb019068e24..6a970b127c9b 100755 --- a/tools/testing/selftests/sysctl/sysctl.sh +++ b/tools/testing/selftests/sysctl/sysctl.sh @@ -38,6 +38,7 @@ ALL_TESTS="$ALL_TESTS 0002:1:1:string_0001" ALL_TESTS="$ALL_TESTS 0003:1:1:int_0002" ALL_TESTS="$ALL_TESTS 0004:1:1:uint_0001" ALL_TESTS="$ALL_TESTS 0005:3:1:int_0003" +ALL_TESTS="$ALL_TESTS 0006:50:1:bitmap_0001" test_modprobe() { @@ -150,6 +151,9 @@ reset_vals() string_0001) VAL="(none)" ;; + bitmap_0001) + VAL="" + ;; *) ;; esac @@ -180,6 +184,22 @@ verify() return 0 } +# proc files get read a page at a time, which can confuse diff, +# and get you incorrect results on proc files with long data. To use +# diff against them you must first extract the output to a file, and +# then compare against that file. +verify_diff_proc_file() +{ + TMP_DUMP_FILE=$(mktemp) + cat $1 > $TMP_DUMP_FILE + + if ! diff -w -q $TMP_DUMP_FILE $2; then + return 1 + else + return 0 + fi +} + verify_diff_w() { echo "$TEST_STR" | diff -q -w -u - $1 > /dev/null @@ -615,6 +635,55 @@ target_exists() return 1 } +run_bitmaptest() { + # Total length of bitmaps string to use, a bit under + # the maximum input size of the test node + LENGTH=$((RANDOM % 65000)) + + # First bit to set + BIT=$((RANDOM % 1024)) + + # String containing our list of bits to set + TEST_STR=$BIT + + # build up the string + while [ "${#TEST_STR}" -le "$LENGTH" ]; do + # Make sure next entry is discontiguous, + # skip ahead at least 2 + BIT=$((BIT + $((2 + RANDOM % 10)))) + + # Add new bit to the list + TEST_STR="${TEST_STR},${BIT}" + + # Randomly make it a range + if [ "$((RANDOM % 2))" -eq "1" ]; then + RANGE_END=$((BIT + $((1 + RANDOM % 10)))) + TEST_STR="${TEST_STR}-${RANGE_END}" + BIT=$RANGE_END + fi + done + + echo -n "Checking bitmap handler... " + TEST_FILE=$(mktemp) + echo -n "$TEST_STR" > $TEST_FILE + + cat $TEST_FILE > $TARGET 2> /dev/null + if [ $? -ne 0 ]; then + echo "FAIL" >&2 + rc=1 + test_rc + fi + + if ! verify_diff_proc_file "$TARGET" "$TEST_FILE"; then + echo "FAIL" >&2 + rc=1 + else + echo "ok" + rc=0 + fi + test_rc +} + sysctl_test_0001() { TARGET="${SYSCTL}/$(get_test_target 0001)" @@ -675,6 +744,14 @@ sysctl_test_0005() run_limit_digit_int_array } +sysctl_test_0006() +{ + TARGET="${SYSCTL}/bitmap_0001" + reset_vals + ORIG="" + run_bitmaptest +} + list_tests() { echo "Test ID list:" @@ -688,6 +765,7 @@ list_tests() echo "0003 x $(get_test_count 0003) - tests proc_dointvec()" echo "0004 x $(get_test_count 0004) - tests proc_douintvec()" echo "0005 x $(get_test_count 0005) - tests proc_douintvec() array" + echo "0006 x $(get_test_count 0006) - tests proc_do_large_bitmap()" } usage() @@ -761,8 +839,7 @@ function run_all_tests() ENABLED=$(get_test_enabled $TEST_ID) TEST_COUNT=$(get_test_count $TEST_ID) TEST_TARGET=$(get_test_target $TEST_ID) - target_exists $TEST_TARGET $TEST_ID - if [ $? -ne 1 ]; then + if target_exists $TEST_TARGET $TEST_ID; then continue fi if [[ $ENABLED -eq "1" ]]; then -- 2.30.2