sanitize hostname a bit more

diff --git a/util.c b/util.c
index 83002f4492ec265c1f370302dfa466ea3375f41d..46619d7ced7432c51c462134f2e50f7ca68323f7 100644 (file)
--- a/util.c
+++ b/util.c
@@ -53,6 +53,7 @@ hostname(void)
 {
        static char name[HOST_NAME_MAX+1];
        static int initialized = 0;
+       char *s;
 
        if (initialized)
                return (name);
@@ -66,20 +67,19 @@ hostname(void)
                 * treat it as a file.
                 */
                FILE *fp;
-               char *res;
 
                fp = fopen(config.mailname, "r");
                if (fp == NULL)
                        goto local;
 
-               res = fgets(name, sizeof(name), fp);
+               s = fgets(name, sizeof(name), fp);
                fclose(fp);
-               if (res == NULL)
+               if (s == NULL)
                        goto local;
 
-               while (*res != 0 && !isspace(*res))
-                       ++res;
-               *res = 0;
+               for (s = name; *s != 0 && (isalnum(*s) || strchr("_.-", *s)); ++s)
+                       /* NOTHING */;
+               *s = 0;
 
                if (!*name)
                        goto local;
@@ -94,12 +94,20 @@ hostname(void)
 
 local:
        if (gethostname(name, sizeof(name)) != 0)
-               strcpy(name, "(unknown hostname)");
+               *name = 0;
        /*
         * gethostname() is allowed to truncate name without NUL-termination
         * and at the same time not return an error.
         */
        name[sizeof(name) - 1] = 0;
+
+       for (s = name; *s != 0 && (isalnum(*s) || strchr("_.-", *s)); ++s)
+               /* NOTHING */;
+       *s = 0;
+
+       if (!*name)
+               snprintf(name, sizeof(name), "unknown-hostname");
+
        initialized = 1;
        return (name);
 }