Remove use of strcpy() and sprintf().

[tinc] / src / utils.c

diff --git a/src/utils.c b/src/utils.c
index 0d7bc02..c374eb5 100644 (file)
--- a/src/utils.c
+++ b/src/utils.c
@@ -18,10 +18,10 @@
     51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
 
+#include "logger.h"
 #include "system.h"
-
-#include "../src/logger.h"
 #include "utils.h"
+#include "xalloc.h"
 
 static const char hexadecimals[] = "0123456789ABCDEF";
 static const char base64_original[] = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
@@ -158,7 +158,7 @@ int b64encode_urlsafe(const void *src, char *dst, int length) {
 const char *winerror(int err) {
        static char buf[1024], *ptr;
 
-       ptr = buf + sprintf(buf, "(%d) ", err);
+       ptr = buf + snprintf(buf, sizeof buf, "(%d) ", err);
 
        if (!FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS,
                NULL, err, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), ptr, sizeof(buf) - (ptr - buf), NULL)) {
@@ -179,3 +179,54 @@ unsigned int bitfield_to_int(const void *bitfield, size_t size) {
        memcpy(&value, bitfield, size);
        return value;
 }
+
+bool check_id(const char *id) {
+       if(!id || !*id)
+               return false;
+
+       for(; *id; id++)
+               if(!isalnum(*id) && *id != '_')
+                       return false;
+
+       return true;
+}
+
+/* Windows doesn't define HOST_NAME_MAX. */
+#ifndef HOST_NAME_MAX
+#define HOST_NAME_MAX 255
+#endif
+
+char *replace_name(const char *name) {
+       char *ret_name;
+
+       if (name[0] == '$') {
+               char *envname = getenv(name + 1);
+               char hostname[HOST_NAME_MAX+1];
+               if (!envname) {
+                       if (strcmp(name + 1, "HOST")) {
+                               logger(DEBUG_ALWAYS, LOG_ERR, "Invalid Name: environment variable %s does not exist\n", name + 1);
+                               return NULL;
+                       }
+                       if (gethostname(hostname, sizeof hostname) || !*hostname) {
+                               logger(DEBUG_ALWAYS, LOG_ERR, "Could not get hostname: %s\n", sockstrerror(sockerrno));
+                               return NULL;
+                       }
+                       hostname[HOST_NAME_MAX] = 0;
+                       envname = hostname;
+               }
+               ret_name = xstrdup(envname);
+               for (char *c = ret_name; *c; c++)
+                       if (!isalnum(*c))
+                               *c = '_';
+       } else {
+               ret_name = xstrdup(name);
+       }
+
+       if (!check_id(ret_name)) {
+               logger(DEBUG_ALWAYS, LOG_ERR, "Invalid name for myself!");
+               free(ret_name);
+               return NULL;
+       }
+
+       return ret_name;
+}