Add two tests to check that uninitialized read are zeroed

test/simple-memory-corruption/Makefile

@@ -34,6 +34,8 @@ EXECUTABLES := \
     invalid_free_unprotected \
     invalid_free_small_region \
     invalid_free_small_region_far \
+    uninitialized_read_small \
+    uninitialized_read_large \
     uninitialized_free \
     uninitialized_realloc \
     uninitialized_malloc_usable_size \

test/simple-memory-corruption/test_smc.py

@@ -211,6 +211,15 @@ class TestSimpleMemoryCorruption(unittest.TestCase):
             "impossibly_large_malloc")
         self.assertEqual(returncode, 0)
 
+    def test_uninitialized_read_small(self):
+        _stdout, stderr, returncode = self.run_test(
+            "uninitialized_read_small")
+        self.assertEqual(returncode, 0)
+
+    def test_uninitialized_read_large(self):
+        _stdout, stderr, returncode = self.run_test(
+            "uninitialized_read_large")
+        self.assertEqual(returncode, 0)
 
 
 if __name__ == '__main__':

test/simple-memory-corruption/uninitialized_read_large.c

@@ -0,0 +1,14 @@
+#include <stdlib.h>
+
+#include "../test_util.h"
+
+OPTNONE int main(void) {
+    char *p = malloc(128 * 1024);
+    for (unsigned i = 0; i < 8; i++) {
+        if (p[i] != 0) {
+            return 1;
+        }
+    }
+    free(p);
+    return 0;
+}

test/simple-memory-corruption/uninitialized_read_small.c

@@ -0,0 +1,14 @@
+#include <stdlib.h>
+
+#include "../test_util.h"
+
+OPTNONE int main(void) {
+    char *p = malloc(8);
+    for (unsigned i = 0; i < 8; i++) {
+        if (p[i] != 0) {
+            return 1;
+        }
+    }
+    free(p);
+    return 0;
+}