X-Git-Url: https://www.tinc-vpn.org/git/browse?a=blobdiff_plain;f=src%2Fxalloc.h;h=34f02d0ec1dd0ac7f20b0eba649c8c7820c358f7;hb=refs%2Fheads%2F1.1;hp=34dac3ccfe260b988fb33abce72b71f3f2508eff;hpb=5822f817aa802c2c5a83e9d99a8ae78cb822799b;p=tinc

diff --git a/src/xalloc.h b/src/xalloc.h
index 34dac3cc..2b217e8b 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>
 
@@ -21,53 +21,76 @@
    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);
-	if(!p)
+
+	if(!p) {
 		abort();
+	}
+
 	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);
-	if(!p)
+
+	if(!p) {
 		abort();
+	}
+
 	return p;
 }
 
 static inline void *xrealloc(void *p, size_t n) {
 	p = realloc(p, n);
-	if(!p)
+
+	if(!p) {
 		abort();
+	}
+
 	return p;
 }
 
-static inline char *xstrdup(const char *s) __attribute__ ((__malloc__));
+static inline char *xstrdup(const char *s) ATTR_MALLOC ATTR_NONNULL;
 static inline char *xstrdup(const char *s) {
 	char *p = strdup(s);
-	if(!p)
+
+	if(!p) {
 		abort();
+	}
+
 	return p;
 }
 
+static inline int xvasprintf(char **strp, const char *fmt, va_list ap) ATTR_FORMAT(printf, 2, 0);
 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);
-	if(result < 0)
+	int result = vsnprintf(buf, sizeof(buf), fmt, ap);
+
+	if(result < 0) {
 		abort();
+	}
+
 	*strp = xstrdup(buf);
 #else
 	int result = vasprintf(strp, fmt, ap);
-	if(result < 0)
+
+	if(result < 0) {
 		abort();
+	}
+
 #endif
 	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);
@@ -76,4 +99,51 @@ 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