Implement memset_s and improve free_secure

4 files changed, 138 insertions, 3 deletions

diff --git a/src/constraint_handler.c b/src/constraint_handler.c
new file mode 100644
index 0000000..ca4e9d2
--- /dev/null
+++ b/src/constraint_handler.c
@@ -0,0 +1,66 @@
+/* constraint_handler.c
+ *
+ * Copyright 2024 axtlos <axtlos@disroot.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: LGPL-3.0-only
+ */
+
+
+#define __STDC_WANT_LIB_EXT1__ 1
+#include "extlib.h"
+
+static constraint_handler_t *_cnstrnt_handler = NULL;
+
+constraint_handler_t
+set_constraint_handler_s (constraint_handler_t handler)
+{
+  constraint_handler_t *new, *old, ret;
+
+  new = malloc (sizeof (constraint_handler_t));
+  if (!new) return NULL;
+  *new = handler;
+  old = _cnstrnt_handler;
+  _cnstrnt_handler = new;
+  if (!old)
+    ret = NULL;
+  else {
+    ret = *old;
+    free (old);
+  }
+  return ret;
+}
+
+void
+throw_constraint_handler_s (const char * restrict msg, errno_t error)
+{
+  constraint_handler_t ch;
+  ch = _cnstrnt_handler != NULL ? *_cnstrnt_handler : NULL;
+  if (ch != NULL)
+    ch (msg, NULL, error);
+}
+
+void
+abort_handler_s (const char *restrict msg, void * restrict ptr, errno_t error)
+{
+  static const char abrt_msg[] = "abort_handler: ";
+
+  fprintf (stderr, "%s", abrt_msg);
+  fprintf (stderr, "%s\n", msg);
+  abort ();
+}
+
+void
+ignore_handler_s (const char * restrict msg, void * restrict ptr, errno_t error)
+{}
diff --git a/src/extlib.c b/src/extlib.c
index 4fa7213..107e8b4 100644
--- a/src/extlib.c
+++ b/src/extlib.c
@@ -20,13 +20,14 @@
 
 #define _XOPEN_SOURCE 500
 #define USE_SECURE_MEM
+#define __STDC_WANT_LIB_EXT1__ 1
 #include <ftw.h>
 
 #include "extlib.h"
 #include <stdlib.h>
 #include <stdio.h>
 #include <string.h>
-
+#include <time.h>
 
 #undef free
 #undef malloc
@@ -34,7 +35,7 @@
 void
 free_secure(void **__ptr, size_t ptrlen)
 {
-  memset (*__ptr, 0, ptrlen);
+  memset_s (*__ptr, ptrlen+1, 0, ptrlen);
   free (*__ptr);
   *__ptr = NULL;
   return;
@@ -43,7 +44,7 @@ free_secure(void **__ptr, size_t ptrlen)
 void *
 malloc_secure (size_t len)
 {
-  void *mem = calloc (0, len);
+  void *mem = calloc (1, len);
   return mem;
 }
 
diff --git a/src/extlib.h b/src/extlib.h
index 87948f5..fc7a3d2 100644
--- a/src/extlib.h
+++ b/src/extlib.h
@@ -20,6 +20,7 @@
 #include <stdlib.h>
 #include <stdio.h>
 #include <unistd.h>
+#include <stdint.h>
 
 #ifdef USE_SECURE_MEM
 #define free(x) error - use free_secure
@@ -32,6 +33,25 @@ void free_secure (void **__ptr, size_t ptrlen);
 void *malloc_secure (size_t len);
 #endif
 
+#if (__STDC_WANT_LIB_EXT1__ == 1)
+#define RSIZE_MAX SIZE_MAX
+typedef int errno_t;
+typedef size_t rsize_t;
+
+typedef void (*constraint_handler_t) (const char *__restrict, void *__restrict, errno_t);
+/// Copy the value of c (converted to an unsigned char) into each of the first n
+/// characters of the object pointed to by s.
+/// Conforms to ISO/IEC 9899:2011 K.3.7.4.1
+errno_t memset_s (void *s, rsize_t max, int c, rsize_t n);
+
+constraint_handler_t set_constraint_handler_s (constraint_handler_t handler);
+void throw_constraint_handler_s (const char *restrict msg, errno_t error);
+_Noreturn void abort_handler_s (const char * __restrict, void * __restrict,
+				errno_t);
+void ignore_handler_s (const char *__restrict, void *__restrict, errno_t);
+#endif
+
+
 /// Copy the data of one filestream to another */
 void fcopy(FILE *f1, FILE *f2);
 
diff --git a/src/memset_s.c b/src/memset_s.c
new file mode 100644
index 0000000..deda5d7
--- /dev/null
+++ b/src/memset_s.c
@@ -0,0 +1,48 @@
+/* memset_s.c
+ *
+ * Copyright 2024 axtlos <axtlos@disroot.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, version 3.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: LGPL-3.0-only
+ */
+
+
+#define __STDC_WANT_LIB_EXT1__ 1
+#include "extlib.h"
+#include <errno.h>
+
+
+errno_t
+memset_s(void *s, rsize_t smax, int c, rsize_t n)
+{
+  volatile unsigned char *dest = (unsigned char *) s;
+  errno_t ret = EINVAL;
+  rsize_t limit = n < smax ? n : smax;
+
+  if (!s)
+    throw_constraint_handler_s("memset_s: s = NULL", ret);
+  else if (n > RSIZE_MAX)
+    throw_constraint_handler_s("memset_s: n > RSIZE_MAX", ret);
+  else if (smax > RSIZE_MAX)
+    throw_constraint_handler_s("memset_s: smax > RSIZE_MAX", ret);
+  else if (n > smax)
+    throw_constraint_handler_s("memset_s: n > smax", ret);
+  else {
+    while (limit > 0)
+      dest[--limit] = (unsigned char)c;
+    ret = 0;
+  }
+  return ret;
+}
+