Add SPDX license identifiers to source files under the LGPL

[thirdparty/systemd.git] / src / resolve / resolved.c

diff --git a/src/resolve/resolved.c b/src/resolve/resolved.c
index 6cef401870efdccfdd2d95ec4cbdd2cf77088a16..a4cda0b5efe9200b3e89bfff05e490858bf3cd95 100644 (file)
--- a/src/resolve/resolved.c
+++ b/src/resolve/resolved.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
 /***
   This file is part of systemd.
 
@@ -61,17 +62,26 @@ int main(int argc, char *argv[]) {
         }
 
         /* Always create the directory where resolv.conf will live */
-        r = mkdir_safe_label("/run/systemd/resolve", 0755, uid, gid);
+        r = mkdir_safe_label("/run/systemd/resolve", 0755, uid, gid, false);
         if (r < 0) {
                 log_error_errno(r, "Could not create runtime directory: %m");
                 goto finish;
         }
 
-        r = drop_privileges(uid, gid, 0);
-        if (r < 0)
-                goto finish;
+        /* Drop privileges, but only if we have been started as root. If we are not running as root we assume all
+         * privileges are already dropped. */
+        if (getuid() == 0) {
+
+                /* Drop privileges, but keep three caps. Note that we drop those too, later on (see below) */
+                r = drop_privileges(uid, gid,
+                                    (UINT64_C(1) << CAP_NET_RAW)|          /* needed for SO_BINDTODEVICE */
+                                    (UINT64_C(1) << CAP_NET_BIND_SERVICE)| /* needed to bind on port 53 */
+                                    (UINT64_C(1) << CAP_SETPCAP)           /* needed in order to drop the caps later */);
+                if (r < 0)
+                        goto finish;
+        }
 
-        assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGTERM, SIGINT, SIGUSR1, -1) >= 0);
+        assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGTERM, SIGINT, SIGUSR1, SIGUSR2, SIGRTMIN+1, -1) >= 0);
 
         r = manager_new(&m);
         if (r < 0) {
@@ -88,6 +98,13 @@ int main(int argc, char *argv[]) {
         /* Write finish default resolv.conf to avoid a dangling symlink */
         (void) manager_write_resolv_conf(m);
 
+        /* Let's drop the remaining caps now */
+        r = capability_bounding_set_drop(0, true);
+        if (r < 0) {
+                log_error_errno(r, "Failed to drop remaining caps: %m");
+                goto finish;
+        }
+
         sd_notify(false,
                   "READY=1\n"
                   "STATUS=Processing requests...");