4 files changed, 59 insertions, 21 deletions

diff --git a/src/libsystemd-network/dhcp-option.c b/src/libsystemd-network/dhcp-option.c
index 5e216c5..5679091 100644
--- a/src/libsystemd-network/dhcp-option.c
+++ b/src/libsystemd-network/dhcp-option.c
@@ -10,6 +10,8 @@
 #include "alloc-util.h"
 #include "dhcp-option.h"
 #include "dhcp-server-internal.h"
+#include "dns-domain.h"
+#include "hostname-util.h"
 #include "memory-util.h"
 #include "ordered-set.h"
 #include "strv.h"
@@ -396,27 +398,56 @@ int dhcp_option_parse(DHCPMessage *message, size_t len, dhcp_option_callback_t c
 }
 
 int dhcp_option_parse_string(const uint8_t *option, size_t len, char **ret) {
+        _cleanup_free_ char *string = NULL;
         int r;
 
         assert(option);
         assert(ret);
 
-        if (len <= 0)
-                *ret = mfree(*ret);
-        else {
-                char *string;
+        if (len <= 0) {
+                *ret = NULL;
+                return 0;
+        }
 
-                /*
-                 * One trailing NUL byte is OK, we don't mind. See:
-                 * https://github.com/systemd/systemd/issues/1337
-                 */
-                r = make_cstring((const char *) option, len, MAKE_CSTRING_ALLOW_TRAILING_NUL, &string);
-                if (r < 0)
-                        return r;
+        /* One trailing NUL byte is OK, we don't mind. See:
+         * https://github.com/systemd/systemd/issues/1337 */
+        r = make_cstring((const char *) option, len, MAKE_CSTRING_ALLOW_TRAILING_NUL, &string);
+        if (r < 0)
+                return r;
+
+        if (!string_is_safe(string) || !utf8_is_valid(string))
+                return -EINVAL;
+
+        *ret = TAKE_PTR(string);
+        return 0;
+}
+
+int dhcp_option_parse_hostname(const uint8_t *option, size_t len, char **ret) {
+        _cleanup_free_ char *hostname = NULL;
+        int r;
 
-                free_and_replace(*ret, string);
+        assert(option);
+        assert(ret);
+
+        r = dhcp_option_parse_string(option, len, &hostname);
+        if (r < 0)
+                return r;
+
+        if (!hostname) {
+                *ret = NULL;
+                return 0;
         }
 
+        if (!hostname_is_valid(hostname, 0))
+                return -EINVAL;
+
+        r = dns_name_is_valid(hostname);
+        if (r < 0)
+                return r;
+        if (r == 0)
+                return -EINVAL;
+
+        *ret = TAKE_PTR(hostname);
         return 0;
 }
 
diff --git a/src/libsystemd-network/dhcp-option.h b/src/libsystemd-network/dhcp-option.h
index 425f5b5..aaa8f84 100644
--- a/src/libsystemd-network/dhcp-option.h
+++ b/src/libsystemd-network/dhcp-option.h
@@ -44,3 +44,4 @@ int dhcp_option_parse(
                 char **ret_error_message);
 
 int dhcp_option_parse_string(const uint8_t *option, size_t len, char **ret);
+int dhcp_option_parse_hostname(const uint8_t *option, size_t len, char **ret);
diff --git a/src/libsystemd-network/sd-dhcp-lease.c b/src/libsystemd-network/sd-dhcp-lease.c
index 4e3be98..202d75f 100644
--- a/src/libsystemd-network/sd-dhcp-lease.c
+++ b/src/libsystemd-network/sd-dhcp-lease.c
@@ -833,12 +833,16 @@ int dhcp_lease_parse_options(uint8_t code, uint8_t len, const void *option, void
 
                 break;
 
-        case SD_DHCP_OPTION_ROOT_PATH:
-                r = dhcp_option_parse_string(option, len, &lease->root_path);
+        case SD_DHCP_OPTION_ROOT_PATH: {
+                _cleanup_free_ char *p = NULL;
+
+                r = dhcp_option_parse_string(option, len, &p);
                 if (r < 0)
                         log_debug_errno(r, "Failed to parse root path, ignoring: %m");
-                break;
 
+                free_and_replace(lease->root_path, p);
+                break;
+        }
         case SD_DHCP_OPTION_RENEWAL_TIME:
                 r = lease_parse_be32_seconds(option, len, /* max_as_infinity = */ true, &lease->t1);
                 if (r < 0)
diff --git a/src/libsystemd-network/sd-dhcp-server.c b/src/libsystemd-network/sd-dhcp-server.c
index fcc5b74..b87e4d6 100644
--- a/src/libsystemd-network/sd-dhcp-server.c
+++ b/src/libsystemd-network/sd-dhcp-server.c
@@ -808,14 +808,16 @@ static int parse_request(uint8_t code, uint8_t len, const void *option, void *us
                 req->agent_info_option = (uint8_t*)option - 2;
 
                 break;
-        case SD_DHCP_OPTION_HOST_NAME:
-                r = dhcp_option_parse_string(option, len, &req->hostname);
-                if (r < 0) {
-                        log_debug_errno(r, "Failed to parse hostname, ignoring: %m");
-                        return 0;
-                }
+        case SD_DHCP_OPTION_HOST_NAME: {
+                _cleanup_free_ char *p = NULL;
 
+                r = dhcp_option_parse_hostname(option, len, &p);
+                if (r < 0)
+                        log_debug_errno(r, "Failed to parse hostname, ignoring: %m");
+                else
+                        free_and_replace(req->hostname, p);
                 break;
+        }
         case SD_DHCP_OPTION_PARAMETER_REQUEST_LIST:
                 req->parameter_request_list = option;
                 req->parameter_request_list_len = len;