malloc-gnu-tests, etc.: test ptrdiff_t overflow

* modules/calloc-gnu-tests (Depends-on):
* modules/malloc-gnu-tests (Depends-on):
* modules/realloc-gnu-tests (Depends-on): Add stdint.
* tests/test-calloc-gnu.c (main):
* tests/test-malloc-gnu.c (main):,
* tests/test-realloc-gnu.c (main): Test for ptrdiff_t overflow.

ChangeLog

@@ -1,5 +1,13 @@
 2021-04-18  Paul Eggert  <eggert@cs.ucla.edu>
 
+	malloc-gnu-tests, etc.: test ptrdiff_t overflow
+	* modules/calloc-gnu-tests (Depends-on):
+	* modules/malloc-gnu-tests (Depends-on):
+	* modules/realloc-gnu-tests (Depends-on): Add stdint.
+	* tests/test-calloc-gnu.c (main):
+	* tests/test-malloc-gnu.c (main):,
+	* tests/test-realloc-gnu.c (main): Test for ptrdiff_t overflow.
+
 	malloc-gnu, etc.: prefer AS_CASE to woolly AS_IF
 	* m4/calloc.m4 (_AC_FUNC_CALLOC_IF):
 	* m4/malloc.m4 (_AC_FUNC_MALLOC_IF):

modules/calloc-gnu-tests

@@ -2,6 +2,7 @@ Files:
 tests/test-calloc-gnu.c
 
 Depends-on:
+stdint
 
 configure.ac:
 

modules/malloc-gnu-tests

@@ -2,6 +2,7 @@ Files:
 tests/test-malloc-gnu.c
 
 Depends-on:
+stdint
 
 configure.ac:
 

modules/realloc-gnu-tests

@@ -2,6 +2,7 @@ Files:
 tests/test-realloc-gnu.c
 
 Depends-on:
+stdint
 
 configure.ac:
 

tests/test-calloc-gnu.c

@@ -17,6 +17,7 @@
 #include <config.h>
 
 #include <stdlib.h>
+#include <stdint.h>
 
 /* Return 8.
    Usual compilers are not able to infer something about the return value.  */
@@ -49,7 +50,7 @@ main ()
      'volatile' is needed to defeat an incorrect optimization by clang 10,
      see <https://bugs.llvm.org/show_bug.cgi?id=46055>.  */
   {
-    void * volatile p = calloc ((size_t) -1 / 8 + 1, eight ());
+    void * volatile p = calloc (SIZE_MAX / 8 + 1, eight ());
     if (p != NULL)
       {
         free (p);
@@ -57,5 +58,16 @@ main ()
       }
   }
 
+  /* Likewise for PTRDIFF_MAX.  */
+  if (PTRDIFF_MAX / 8 < SIZE_MAX)
+    {
+      void * volatile p = calloc (PTRDIFF_MAX / 8 + 1, eight ());
+      if (p != NULL)
+        {
+          free (p);
+          return 2;
+        }
+    }
+
   return 0;
 }

tests/test-malloc-gnu.c

@@ -17,6 +17,7 @@
 #include <config.h>
 
 #include <stdlib.h>
+#include <stdint.h>
 
 int
 main ()
@@ -25,7 +26,15 @@ main ()
   char *p = malloc (0);
   if (p == NULL)
     return 1;
-
   free (p);
+
+  /* Check that malloc (n) fails when n exceeds PTRDIFF_MAX.  */
+  if (PTRDIFF_MAX < SIZE_MAX)
+    {
+      size_t n = PTRDIFF_MAX, n1 = n + 1;
+      if (malloc (n1) != NULL)
+        return 1;
+    }
+
   return 0;
 }

tests/test-realloc-gnu.c

@@ -17,6 +17,7 @@
 #include <config.h>
 
 #include <stdlib.h>
+#include <stdint.h>
 
 int
 main ()
@@ -26,6 +27,15 @@ main ()
   if (p == NULL)
     return 1;
 
+  /* Check that realloc (p, n) fails when p is non-null and n exceeds
+     PTRDIFF_MAX.  */
+  if (PTRDIFF_MAX < SIZE_MAX)
+    {
+      size_t n = PTRDIFF_MAX, n1 = n + 1;
+      if (realloc (p, n1) != NULL)
+        return 1;
+    }
+
   free (p);
   return 0;
 }