test_sysctl: add simple proc_dointvec() case

Test against a simple proc_dointvec() case.  While at it, add a test
against INT_MAX.  Make sure INT_MAX works, and INT_MAX+1 will fail.
Also test negative values work.

Link: http://lkml.kernel.org/r/20170630224431.17374-5-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>

2 files changed, 73 insertions, 0 deletions

diff --git a/lib/test_sysctl.c b/lib/test_sysctl.c
index b2163bfb6eb2..1472e1ae4931 100644
--- a/lib/test_sysctl.c
+++ b/lib/test_sysctl.c
@@ -41,11 +41,15 @@ static int i_one_hundred = 100;
 
 struct test_sysctl_data {
         int int_0001;
+        int int_0002;
+
         char string_0001[65];
 };
 
 static struct test_sysctl_data test_data = {
         .int_0001 = 60,
+        .int_0002 = 1,
+
         .string_0001 = "(none)",
 };
 
@@ -61,6 +65,13 @@ static struct ctl_table test_table[] = {
                 .extra2         = &i_one_hundred,
         },
         {
+                .procname       = "int_0002",
+                .data           = &test_data.int_0002,
+                .maxlen         = sizeof(int),
+                .mode           = 0644,
+                .proc_handler   = proc_dointvec,
+        },
+        {
                 .procname       = "string_0001",
                 .data           = &test_data.string_0001,
                 .maxlen         = sizeof(test_data.string_0001),
diff --git a/tools/testing/selftests/sysctl/sysctl.sh b/tools/testing/selftests/sysctl/sysctl.sh
index 6ec807576f7c..7ba3fa2bbd54 100644
--- a/tools/testing/selftests/sysctl/sysctl.sh
+++ b/tools/testing/selftests/sysctl/sysctl.sh
@@ -31,6 +31,7 @@ TEST_FILE=$(mktemp)
 # we have tons of space.
 ALL_TESTS="0001:1:1"
 ALL_TESTS="$ALL_TESTS 0002:1:1"
+ALL_TESTS="$ALL_TESTS 0003:1:1"
 
 test_modprobe()
 {
@@ -82,6 +83,9 @@ function check_production_sysctl_writes_strict()
         if [ -z $MAX_DIGITS ]; then
                 MAX_DIGITS=$(($PAGE_SIZE/8))
         fi
+        if [ -z $INT_MAX ]; then
+                INT_MAX=$(getconf INT_MAX)
+        fi
 }
 
 test_reqs()
@@ -122,6 +126,9 @@ reset_vals()
                 int_0001)
                         VAL="60"
                         ;;
+                int_0002)
+                        VAL="1"
+                        ;;
                 string_0001)
                         VAL="(none)"
                         ;;
@@ -296,6 +303,48 @@ run_limit_digit()
         test_rc
 }
 
+# You are using an int
+run_limit_digit_int()
+{
+        echo -n "Testing INT_MAX works ..."
+        reset_vals
+        TEST_STR="$INT_MAX"
+        echo -n $TEST_STR > $TARGET
+
+        if ! verify "${TARGET}"; then
+                echo "FAIL" >&2
+                rc=1
+        else
+                echo "ok"
+        fi
+        test_rc
+
+        echo -n "Testing INT_MAX + 1 will fail as expected..."
+        reset_vals
+        let TEST_STR=$INT_MAX+1
+        echo -n $TEST_STR > $TARGET 2> /dev/null
+
+        if verify "${TARGET}"; then
+                echo "FAIL" >&2
+                rc=1
+        else
+                echo "ok"
+        fi
+        test_rc
+
+        echo -n "Testing negative values will work as expected..."
+        reset_vals
+        TEST_STR="-3"
+        echo -n $TEST_STR > $TARGET 2> /dev/null
+        if ! verify "${TARGET}"; then
+                echo "FAIL" >&2
+                rc=1
+        else
+                echo "ok"
+        fi
+        test_rc
+}
+
 run_stringtests()
 {
         echo -n "Writing entire sysctl in short writes ... "
@@ -389,6 +438,18 @@ sysctl_test_0002()
         run_stringtests
 }
 
+sysctl_test_0003()
+{
+        TARGET="${SYSCTL}/int_0002"
+        reset_vals
+        ORIG=$(cat "${TARGET}")
+        TEST_STR=$(( $ORIG + 1 ))
+
+        run_numerictests
+        run_limit_digit
+        run_limit_digit_int
+}
+
 list_tests()
 {
         echo "Test ID list:"
@@ -399,6 +460,7 @@ list_tests()
         echo
         echo "0001 x $(get_test_count 0001) - tests proc_dointvec_minmax()"
         echo "0002 x $(get_test_count 0002) - tests proc_dostring()"
+        echo "0003 x $(get_test_count 0003) - tests proc_dointvec()"
 }
 
 test_reqs