Added submodule contents into tree

externals/mbedtls/programs/test/zeroize.c

@@ -0,0 +1,72 @@
+/*
+ * Zeroize application for debugger-driven testing
+ *
+ * This is a simple test application used for debugger-driven testing to check
+ * whether calls to mbedtls_platform_zeroize() are being eliminated by compiler
+ * optimizations. This application is used by the GDB script at
+ * tests/scripts/test_zeroize.gdb: the script sets a breakpoint at the last
+ * return statement in the main() function of this program. The debugger
+ * facilities are then used to manually inspect the memory and verify that the
+ * call to mbedtls_platform_zeroize() was not eliminated.
+ *
+ *  Copyright The Mbed TLS Contributors
+ *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
+ */
+
+#include "mbedtls/build_info.h"
+
+#include <stdio.h>
+
+#include "mbedtls/platform.h"
+
+#include "mbedtls/platform_util.h"
+
+#define BUFFER_LEN 1024
+
+void usage(void)
+{
+    mbedtls_printf("Zeroize is a simple program to assist with testing\n");
+    mbedtls_printf("the mbedtls_platform_zeroize() function by using the\n");
+    mbedtls_printf("debugger. This program takes a file as input and\n");
+    mbedtls_printf("prints the first %d characters. Usage:\n\n", BUFFER_LEN);
+    mbedtls_printf("       zeroize <FILE>\n");
+}
+
+int main(int argc, char **argv)
+{
+    int exit_code = MBEDTLS_EXIT_FAILURE;
+    FILE *fp;
+    char buf[BUFFER_LEN];
+    char *p = buf;
+    char *end = p + BUFFER_LEN;
+    int c;
+
+    if (argc != 2) {
+        mbedtls_printf("This program takes exactly 1 argument\n");
+        usage();
+        mbedtls_exit(exit_code);
+    }
+
+    fp = fopen(argv[1], "r");
+    if (fp == NULL) {
+        mbedtls_printf("Could not open file '%s'\n", argv[1]);
+        mbedtls_exit(exit_code);
+    }
+
+    while ((c = fgetc(fp)) != EOF && p < end - 1) {
+        *p++ = (char) c;
+    }
+    *p = '\0';
+
+    if (p - buf != 0) {
+        mbedtls_printf("%s\n", buf);
+        exit_code = MBEDTLS_EXIT_SUCCESS;
+    } else {
+        mbedtls_printf("The file is empty!\n");
+    }
+
+    fclose(fp);
+    mbedtls_platform_zeroize(buf, sizeof(buf));
+
+    mbedtls_exit(exit_code);   // GDB_BREAK_HERE -- don't remove this comment!
+}