X-Git-Url: https://tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fxalloc.h;h=c8cfbebfb1bae47c921ff0207e0e19e06c543e19;hb=e62fd508158749a0d55eae06c2e361df5d6da6e0;hp=ac24ebc6b424a0b0f504de5a40525c36f217e4f2;hpb=953f5b4231bbbb8269bb0c55b96a1c8c4bb34a59;p=tinc

diff --git a/src/xalloc.h b/src/xalloc.h
index ac24ebc6..c8cfbebf 100644
--- a/src/xalloc.h
+++ b/src/xalloc.h
@@ -2,7 +2,7 @@
 #define TINC_XALLOC_H
 
 /*
-   xalloc.h -- malloc and related fuctions with out of memory checking
+   xalloc.h -- malloc and related functions with out of memory checking
    Copyright (C) 1990, 91, 92, 93, 94, 95, 96, 97 Free Software Foundation, Inc.
    Copyright (C) 2011-2013 Guus Sliepen <guus@tinc-vpn.org>
 
@@ -21,7 +21,11 @@
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
-static inline void *xmalloc(size_t n) __attribute__((__malloc__));
+#include "system.h"
+
+#include <assert.h>
+
+static inline void *xmalloc(size_t n) ATTR_MALLOC;
 static inline void *xmalloc(size_t n) {
 	void *p = malloc(n);
 
@@ -32,7 +36,7 @@ static inline void *xmalloc(size_t n) {
 	return p;
 }
 
-static inline void *xzalloc(size_t n) __attribute__((__malloc__));
+static inline void *xzalloc(size_t n) ATTR_MALLOC;
 static inline void *xzalloc(size_t n) {
 	void *p = calloc(1, n);
 
@@ -53,7 +57,7 @@ static inline void *xrealloc(void *p, size_t n) {
 	return p;
 }
 
-static inline char *xstrdup(const char *s) __attribute__((__malloc__, __nonnull__));
+static inline char *xstrdup(const char *s) ATTR_MALLOC ATTR_NONNULL;
 static inline char *xstrdup(const char *s) {
 	char *p = strdup(s);
 
@@ -65,7 +69,7 @@ static inline char *xstrdup(const char *s) {
 }
 
 static inline int xvasprintf(char **strp, const char *fmt, va_list ap) {
-#ifdef HAVE_MINGW
+#ifdef HAVE_WINDOWS
 	char buf[1024];
 	int result = vsnprintf(buf, sizeof(buf), fmt, ap);
 
@@ -85,7 +89,7 @@ static inline int xvasprintf(char **strp, const char *fmt, va_list ap) {
 	return result;
 }
 
-static inline int xasprintf(char **strp, const char *fmt, ...) __attribute__((__format__(printf, 2, 3)));
+static inline int xasprintf(char **strp, const char *fmt, ...) ATTR_FORMAT(printf, 2, 3);
 static inline int xasprintf(char **strp, const char *fmt, ...) {
 	va_list ap;
 	va_start(ap, fmt);
@@ -94,4 +98,51 @@ static inline int xasprintf(char **strp, const char *fmt, ...) {
 	return result;
 }
 
+// Zero out a block of memory containing sensitive information using whatever secure
+// erase function is available on the platform (or an unreliable fallback if none are).
+// The pointer must not be NULL. Length can be zero, in which case the call is a noop.
+static inline void memzero(void *buf, size_t buflen) ATTR_NONNULL;
+static inline void memzero(void *buf, size_t buflen) {
+	assert(buf);
+
+	if(!buflen) {
+		return;
+	}
+
+#if defined(HAVE_EXPLICIT_BZERO)
+	explicit_bzero(buf, buflen);
+#elif defined(HAVE_EXPLICIT_MEMSET)
+	explicit_memset(buf, 0, buflen);
+#elif defined(HAVE_MEMSET_S)
+	errno_t err = memset_s(buf, buflen, 0, buflen);
+	assert(err == 0);
+#elif defined(HAVE_WINDOWS)
+	SecureZeroMemory(buf, buflen);
+#else
+	volatile uint8_t *p = buf;
+
+	while(buflen--) {
+		*p++ = 0;
+	}
+
 #endif
+}
+
+// Zero out a buffer of size `len` located at `ptr` and free() it.
+// Does nothing if called on NULL.
+static inline void xzfree(void *ptr, size_t len) {
+	if(ptr) {
+		memzero(ptr, len);
+		free(ptr);
+	}
+}
+
+// Zero out a NULL-terminated string using memzero() and then free it.
+// Does nothing if called on NULL.
+static inline void free_string(char *str) {
+	if(str) {
+		xzfree(str, strlen(str));
+	}
+}
+
+#endif // TINC_XALLOC_H