4 files changed, 31 insertions, 17 deletions

diff --git a/src/basic/hostname-util.c b/src/basic/hostname-util.c
index e336f269fa..d901a5e82b 100644
--- a/src/basic/hostname-util.c
+++ b/src/basic/hostname-util.c
@@ -61,14 +61,22 @@ static bool hostname_valid_char(char c) {
                 c == '.';
 }
 
-bool hostname_is_valid(const char *s) {
+/**
+ * Check if s looks like a valid host name or fqdn. This does not do
+ * full DNS validation, but only checks if the name is composed of
+ * allowed characters and the length is not above the maximum allowed
+ * by Linux (c.f. dns_name_is_valid()). Trailing dot is allowed if
+ * relax is true and at least two components are present in the name.
+ */
+bool hostname_is_valid(const char *s, bool relax) {
         const char *p;
         bool dot;
+        unsigned dots = 0;
 
         if (isempty(s))
                 return false;
 
-        /* Doesn't accept empty hostnames, hostnames with trailing or
+        /* Doesn't accept empty hostnames, hostnames with
          * leading dots, and hostnames with multiple dots in a
          * sequence. Also ensures that the length stays below
          * HOST_NAME_MAX. */
@@ -79,6 +87,7 @@ bool hostname_is_valid(const char *s) {
                                 return false;
 
                         dot = true;
+                        dots ++;
                 } else {
                         if (!hostname_valid_char(*p))
                                 return false;
@@ -87,7 +96,7 @@ bool hostname_is_valid(const char *s) {
                 }
         }
 
-        if (dot)
+        if (dot && (dots < 2 || !relax))
                 return false;
 
         if (p-s > HOST_NAME_MAX)
@@ -96,7 +105,7 @@ bool hostname_is_valid(const char *s) {
         return true;
 }
 
-char* hostname_cleanup(char *s, bool lowercase) {
+char* hostname_cleanup(char *s) {
         char *p, *d;
         bool dot;
 
@@ -110,7 +119,7 @@ char* hostname_cleanup(char *s, bool lowercase) {
                         *(d++) = '.';
                         dot = true;
                 } else if (hostname_valid_char(*p)) {
-                        *(d++) = lowercase ? tolower(*p) : *p;
+                        *(d++) = *p;
                         dot = false;
                 }
 
@@ -132,14 +141,14 @@ bool is_localhost(const char *hostname) {
         /* This tries to identify local host and domain names
          * described in RFC6761 plus the redhatism of .localdomain */
 
-        return streq(hostname, "localhost") ||
-               streq(hostname, "localhost.") ||
-               streq(hostname, "localdomain.") ||
-               streq(hostname, "localdomain") ||
-               endswith(hostname, ".localhost") ||
-               endswith(hostname, ".localhost.") ||
-               endswith(hostname, ".localdomain") ||
-               endswith(hostname, ".localdomain.");
+        return strcaseeq(hostname, "localhost") ||
+               strcaseeq(hostname, "localhost.") ||
+               strcaseeq(hostname, "localdomain.") ||
+               strcaseeq(hostname, "localdomain") ||
+               endswith_no_case(hostname, ".localhost") ||
+               endswith_no_case(hostname, ".localhost.") ||
+               endswith_no_case(hostname, ".localdomain") ||
+               endswith_no_case(hostname, ".localdomain.");
 }
 
 int sethostname_idempotent(const char *s) {
@@ -176,7 +185,7 @@ int read_hostname_config(const char *path, char **hostname) {
                 truncate_nl(l);
                 if (l[0] != '\0' && l[0] != '#') {
                         /* found line with value */
-                        name = hostname_cleanup(l, false);
+                        name = hostname_cleanup(l);
                         name = strdup(name);
                         if (!name)
                                 return -ENOMEM;
diff --git a/src/basic/hostname-util.h b/src/basic/hostname-util.h
index 0c4763cf5a..6f2b5b66ff 100644
--- a/src/basic/hostname-util.h
+++ b/src/basic/hostname-util.h
@@ -29,8 +29,8 @@ bool hostname_is_set(void);
 
 char* gethostname_malloc(void);
 
-bool hostname_is_valid(const char *s) _pure_;
-char* hostname_cleanup(char *s, bool lowercase);
+bool hostname_is_valid(const char *s, bool relax) _pure_;
+char* hostname_cleanup(char *s);
 
 bool is_localhost(const char *hostname);
 
diff --git a/src/basic/util.c b/src/basic/util.c
index af58dc3766..d4d3d3c83a 100644
--- a/src/basic/util.c
+++ b/src/basic/util.c
@@ -3008,7 +3008,7 @@ char* strshorten(char *s, size_t l) {
 
 bool machine_name_is_valid(const char *s) {
 
-        if (!hostname_is_valid(s))
+        if (!hostname_is_valid(s, false))
                 return false;
 
         /* Machine names should be useful hostnames, but also be
diff --git a/src/basic/util.h b/src/basic/util.h
index 0a0fba9012..426b7f7d16 100644
--- a/src/basic/util.h
+++ b/src/basic/util.h
@@ -864,6 +864,11 @@ int unquote_first_word(const char **p, char **ret, UnquoteFlags flags);
 int unquote_first_word_and_warn(const char **p, char **ret, UnquoteFlags flags, const char *unit, const char *filename, unsigned line, const char *rvalue);
 int unquote_many_words(const char **p, UnquoteFlags flags, ...) _sentinel_;
 
+static inline void free_and_replace(char **s, char *v) {
+        free(*s);
+        *s = v;
+}
+
 int free_and_strdup(char **p, const char *s);
 
 #define INOTIFY_EVENT_MAX (sizeof(struct inotify_event) + NAME_MAX + 1)