9 files changed, 33 insertions, 9 deletions
diff --git a/lisp/net/tramp-adb.el b/lisp/net/tramp-adb.el
index dbbbfe6a3f9..8138d9a3608 100644
--- a/lisp/net/tramp-adb.el
+++ b/lisp/net/tramp-adb.el
@@ -164,7 +164,7 @@ It is used for TCP/IP devices."
     (make-auto-save-file-name . tramp-handle-make-auto-save-file-name)
     (make-directory . tramp-adb-handle-make-directory)
     (make-directory-internal . ignore)
-    ;; `make-lock-file-name' performed by default handler.
+    (make-lock-file-name . tramp-handle-make-lock-file-name)
     (make-nearby-temp-file . tramp-handle-make-nearby-temp-file)
     (make-process . tramp-adb-handle-make-process)
     (make-symbolic-link . tramp-handle-make-symbolic-link)
diff --git a/lisp/net/tramp-crypt.el b/lisp/net/tramp-crypt.el
index 1b77fea7e18..109db3b1d7b 100644
--- a/lisp/net/tramp-crypt.el
+++ b/lisp/net/tramp-crypt.el
@@ -213,7 +213,7 @@ If NAME doesn't belong to a crypted remote directory, retun nil."
     (make-auto-save-file-name . tramp-handle-make-auto-save-file-name)
     (make-directory . tramp-crypt-handle-make-directory)
     (make-directory-internal . ignore)
-    ;; `make-lock-file-name' performed by default handler.
+    (make-lock-file-name . tramp-handle-make-lock-file-name)
     (make-nearby-temp-file . tramp-handle-make-nearby-temp-file)
     (make-process . ignore)
     (make-symbolic-link . tramp-handle-make-symbolic-link)
diff --git a/lisp/net/tramp-gvfs.el b/lisp/net/tramp-gvfs.el
index 04de5defb37..022fdeeb885 100644
--- a/lisp/net/tramp-gvfs.el
+++ b/lisp/net/tramp-gvfs.el
@@ -805,7 +805,7 @@ It has been changed in GVFS 1.14.")
     (make-auto-save-file-name . tramp-handle-make-auto-save-file-name)
     (make-directory . tramp-gvfs-handle-make-directory)
     (make-directory-internal . ignore)
-    ;; `make-lock-file-name' performed by default handler.
+    (make-lock-file-name . tramp-handle-make-lock-file-name)
     (make-nearby-temp-file . tramp-handle-make-nearby-temp-file)
     (make-process . ignore)
     (make-symbolic-link . tramp-handle-make-symbolic-link)
diff --git a/lisp/net/tramp-rclone.el b/lisp/net/tramp-rclone.el
index 473fa8a8f0e..49e366c01c6 100644
--- a/lisp/net/tramp-rclone.el
+++ b/lisp/net/tramp-rclone.el
@@ -127,7 +127,7 @@
     (make-auto-save-file-name . tramp-handle-make-auto-save-file-name)
     (make-directory . tramp-fuse-handle-make-directory)
     (make-directory-internal . ignore)
-    ;; `make-lock-file-name' performed by default handler.
+    (make-lock-file-name . tramp-handle-make-lock-file-name)
     (make-nearby-temp-file . tramp-handle-make-nearby-temp-file)
     (make-process . ignore)
     (make-symbolic-link . tramp-handle-make-symbolic-link)
diff --git a/lisp/net/tramp-sh.el b/lisp/net/tramp-sh.el
index 3595bd26557..760320d7ed4 100644
--- a/lisp/net/tramp-sh.el
+++ b/lisp/net/tramp-sh.el
@@ -993,7 +993,7 @@ Format specifiers \"%s\" are replaced before the script is used.")
     (make-auto-save-file-name . tramp-handle-make-auto-save-file-name)
     (make-directory . tramp-sh-handle-make-directory)
     ;; `make-directory-internal' performed by default handler.
-    ;; `make-lock-file-name' performed by default handler.
+    (make-lock-file-name . tramp-handle-make-lock-file-name)
     (make-nearby-temp-file . tramp-handle-make-nearby-temp-file)
     (make-process . tramp-sh-handle-make-process)
     (make-symbolic-link . tramp-sh-handle-make-symbolic-link)
diff --git a/lisp/net/tramp-smb.el b/lisp/net/tramp-smb.el
index 1c7ddee0086..4008c25d3af 100644
--- a/lisp/net/tramp-smb.el
+++ b/lisp/net/tramp-smb.el
@@ -278,7 +278,7 @@ See `tramp-actions-before-shell' for more info.")
     (make-auto-save-file-name . tramp-handle-make-auto-save-file-name)
     (make-directory . tramp-smb-handle-make-directory)
     (make-directory-internal . tramp-smb-handle-make-directory-internal)
-    ;; `make-lock-file-name' performed by default handler.
+    (make-lock-file-name . tramp-handle-make-lock-file-name)
     (make-nearby-temp-file . tramp-handle-make-nearby-temp-file)
     (make-process . ignore)
     (make-symbolic-link . tramp-smb-handle-make-symbolic-link)
diff --git a/lisp/net/tramp-sshfs.el b/lisp/net/tramp-sshfs.el
index 5f6807a0db7..99f4063988f 100644
--- a/lisp/net/tramp-sshfs.el
+++ b/lisp/net/tramp-sshfs.el
@@ -127,7 +127,7 @@
     (make-auto-save-file-name . tramp-handle-make-auto-save-file-name)
     (make-directory . tramp-fuse-handle-make-directory)
     (make-directory-internal . ignore)
-    ;; `make-lock-file-name' performed by default handler.
+    (make-lock-file-name . tramp-handle-make-lock-file-name)
     (make-nearby-temp-file . tramp-handle-make-nearby-temp-file)
     (make-process . tramp-handle-make-process)
     (make-symbolic-link . tramp-handle-make-symbolic-link)
diff --git a/lisp/net/tramp-sudoedit.el b/lisp/net/tramp-sudoedit.el
index d68a5c1adf4..45d9fab986c 100644
--- a/lisp/net/tramp-sudoedit.el
+++ b/lisp/net/tramp-sudoedit.el
@@ -120,7 +120,7 @@ See `tramp-actions-before-shell' for more info.")
     (make-auto-save-file-name . tramp-handle-make-auto-save-file-name)
     (make-directory . tramp-sudoedit-handle-make-directory)
     (make-directory-internal . ignore)
-    ;; `make-lock-file-name' performed by default handler.
+    (make-lock-file-name . tramp-handle-make-lock-file-name)
     (make-nearby-temp-file . tramp-handle-make-nearby-temp-file)
     (make-process . ignore)
     (make-symbolic-link . tramp-sudoedit-handle-make-symbolic-link)
diff --git a/lisp/net/tramp.el b/lisp/net/tramp.el
index 9e6bfceb49a..3f586c62170 100644
--- a/lisp/net/tramp.el
+++ b/lisp/net/tramp.el
@@ -3630,7 +3630,7 @@ User is always nil."
 	     (file-writable-p (file-name-directory filename)))))))
 
 (defcustom tramp-allow-unsafe-temporary-files nil
-  "Whether root-owned auto-save or backup files can be written to \"/tmp\"."
+  "Whether root-owned auto-save, backup or lock files can be written to \"/tmp\"."
   :version "28.1"
   :type 'boolean)
 
@@ -3880,6 +3880,30 @@ Return nil when there is no lockfile."
              (write-region info nil lockname)
              (set-file-modes lockname #o0644))))))))
 
+(defun tramp-handle-make-lock-file-name (file)
+  "Like `make-lock-file-name' for Tramp files."
+  (when (and create-lockfiles
+	     ;; This variable has been introduced with Emacs 28.1.
+	     (not (bound-and-true-p remote-file-name-inhibit-locks)))
+    (with-parsed-tramp-file-name file nil
+      (let ((result
+	     ;; Run plain `make-lock-file-name'.
+	     (tramp-run-real-handler #'make-lock-file-name (list file))))
+	;; Protect against security hole.
+	(when (and (not tramp-allow-unsafe-temporary-files)
+		   (file-in-directory-p result temporary-file-directory)
+		   (zerop (or (tramp-compat-file-attribute-user-id
+			       (file-attributes file 'integer))
+			      tramp-unknown-id-integer))
+		   (not (with-tramp-connection-property
+			    (tramp-get-process v) "unsafe-temporary-file"
+			  (yes-or-no-p
+			   (concat
+			    "Lock file on local temporary directory, "
+			    "do you want to continue? ")))))
+	  (tramp-error v 'file-error "Unsafe lock file name"))
+	result))))
+
 (defun tramp-handle-unlock-file (file)
   "Like `unlock-file' for Tramp files."
   (when-let ((lockname (tramp-compat-make-lock-file-name file)))