Root emacsclient no longer connects to non-root sockets

* lib-src/emacsclient.c (set_local_socket): Don't ignore socket
ownership when run by root.
Ref: http://lists.gnu.org/r/emacs-devel/2018-11/msg00019.html

2 files changed, 10 insertions, 9 deletions

diff --git a/etc/NEWS b/etc/NEWS
index bbcd7a5747a..2f07abb4eb5 100644
--- a/etc/NEWS
+++ b/etc/NEWS
@@ -119,13 +119,19 @@ the new version of the file again.)
 
 * Changes in Emacs 27.1
 
+** emacsclient
+
 +++
-** emacsclient now supports the 'EMACS_SOCKET_NAME' environment variable.
+*** emacsclient now supports the 'EMACS_SOCKET_NAME' environment variable.
 The behavior is identical to 'EMACS_SERVER_FILE', in that the
 command-line value specified via '--socket-name' will override the
 environment, and the natural default to TMPDIR, then "/tmp", continues
 to apply.
 
+---
+*** When run by root, emacsclient no longer connects to non-root sockets.
+(Instead you can use Tramp methods to run root commands in a non-root Emacs.)
+
 +++
 ** The function 'read-passwd' uses '*' as default character to hide passwords.
 
diff --git a/lib-src/emacsclient.c b/lib-src/emacsclient.c
index 42b8dd6227b..6fbc2300958 100644
--- a/lib-src/emacsclient.c
+++ b/lib-src/emacsclient.c
@@ -1365,14 +1365,9 @@ set_local_socket (const char *local_socket_name)
     switch (sock_status)
       {
       case 1:
-        /* There's a socket, but it isn't owned by us.  This is OK if
-           we are root. */
-        if (0 != geteuid ())
-          {
-            message (true, "%s: Invalid socket owner\n", progname);
-            return INVALID_SOCKET;
-          }
-        break;
+        /* There's a socket, but it isn't owned by us.  */
+        message (true, "%s: Invalid socket owner\n", progname);
+        return INVALID_SOCKET;
 
       case 2:
         /* `stat' failed */