test_sysctl: test against int proc_dointvec() array support

Add a few initial respective tests for an array:

  o Echoing values separated by spaces works
  o Echoing only first elements will set first elements
  o Confirm PAGE_SIZE limit still applies even if an array is used

Link: http://lkml.kernel.org/r/20170630224431.17374-7-mcgrof@kernel.org
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 89 insertions, 0 deletions

diff --git a/tools/testing/selftests/sysctl/sysctl.sh b/tools/testing/selftests/sysctl/sysctl.sh
index abeef675a884..ec232c3cfcaa 100644
--- a/tools/testing/selftests/sysctl/sysctl.sh
+++ b/tools/testing/selftests/sysctl/sysctl.sh
@@ -33,6 +33,7 @@ ALL_TESTS="0001:1:1"
 ALL_TESTS="$ALL_TESTS 0002:1:1"
 ALL_TESTS="$ALL_TESTS 0003:1:1"
 ALL_TESTS="$ALL_TESTS 0004:1:1"
+ALL_TESTS="$ALL_TESTS 0005:3:1"
 
 test_modprobe()
 {
@@ -108,6 +109,10 @@ test_reqs()
                 echo "$0: You need getconf installed"
                 exit 1
         fi
+        if ! which diff 2> /dev/null > /dev/null; then
+                echo "$0: You need diff installed"
+                exit 1
+        fi
 }
 
 function load_req_mod()
@@ -167,6 +172,12 @@ verify()
         return 0
 }
 
+verify_diff_w()
+{
+        echo "$TEST_STR" | diff -q -w -u - $1
+        return $?
+}
+
 test_rc()
 {
         if [[ $rc != 0 ]]; then
@@ -352,6 +363,74 @@ run_limit_digit_int()
         test_rc
 }
 
+# You used an int array
+run_limit_digit_int_array()
+{
+        echo -n "Testing array works as expected ... "
+        TEST_STR="4 3 2 1"
+        echo -n $TEST_STR > $TARGET
+
+        if ! verify_diff_w "${TARGET}"; then
+                echo "FAIL" >&2
+                rc=1
+        else
+                echo "ok"
+        fi
+        test_rc
+
+        echo -n "Testing skipping trailing array elements works ... "
+        # Do not reset_vals, carry on the values from the last test.
+        # If we only echo in two digits the last two are left intact
+        TEST_STR="100 101"
+        echo -n $TEST_STR > $TARGET
+        # After we echo in, to help diff we need to set on TEST_STR what
+        # we expect the result to be.
+        TEST_STR="100 101 2 1"
+
+        if ! verify_diff_w "${TARGET}"; then
+                echo "FAIL" >&2
+                rc=1
+        else
+                echo "ok"
+        fi
+        test_rc
+
+        echo -n "Testing PAGE_SIZE limit on array works ... "
+        # Do not reset_vals, carry on the values from the last test.
+        # Even if you use an int array, you are still restricted to
+        # MAX_DIGITS, this is a known limitation. Test limit works.
+        LIMIT=$((MAX_DIGITS -1))
+        TEST_STR="9"
+        (perl -e 'print " " x '$LIMIT';'; echo "${TEST_STR}") | \
+                dd of="${TARGET}" 2>/dev/null
+
+        TEST_STR="9 101 2 1"
+        if ! verify_diff_w "${TARGET}"; then
+                echo "FAIL" >&2
+                rc=1
+        else
+                echo "ok"
+        fi
+        test_rc
+
+        echo -n "Testing exceeding PAGE_SIZE limit fails as expected ... "
+        # Do not reset_vals, carry on the values from the last test.
+        # Now go over limit.
+        LIMIT=$((MAX_DIGITS))
+        TEST_STR="7"
+        (perl -e 'print " " x '$LIMIT';'; echo "${TEST_STR}") | \
+                dd of="${TARGET}" 2>/dev/null
+
+        TEST_STR="7 101 2 1"
+        if verify_diff_w "${TARGET}"; then
+                echo "FAIL" >&2
+                rc=1
+        else
+                echo "ok"
+        fi
+        test_rc
+}
+
 # You are using an unsigned int
 run_limit_digit_uint()
 {
@@ -512,6 +591,15 @@ sysctl_test_0004()
         run_limit_digit_uint
 }
 
+sysctl_test_0005()
+{
+        TARGET="${SYSCTL}/int_0003"
+        reset_vals
+        ORIG=$(cat "${TARGET}")
+
+        run_limit_digit_int_array
+}
+
 list_tests()
 {
         echo "Test ID list:"
@@ -524,6 +612,7 @@ list_tests()
         echo "0002 x $(get_test_count 0002) - tests proc_dostring()"
         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"
 }
 
 test_reqs