emacs/emacs-23.1-rst.patch

Description: Patch to fix temporary file vulnerability
 My approach is based on the premise that the make-temp-file function
 provided from Emacs 22 onwards is safe. So, I backport the method to
 the rst.el file, and bind it to the symbol rst--make-temp-file as
 follows:

 - If the Emacs version is less than 22, use this custom version. This
   works on Emacs 21, I tested it.
 - If the Emacs version is 22 or more, bind rst--make-temp-file to the
   make-temp-fil provided in the Emacs Lisp libraries.

 I don't see a solution for removing the temporary files, though.

 I am no expert on security or Emacs Lisp, but I hope this patch
 provides a start.

Author: Kumar Appaiah <akumar@debian.org>
Addopted due bug bnc#642787 for emacs 23.1 by Werner Fink <werner@suse.de>
---

 rst.el |   48 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 46 insertions(+), 2 deletions(-)

--- lisp/textmodes/rst.el
+++ lisp/textmodes/rst.el	2010-10-06 09:50:28.779926181 +0000
@@ -3297,10 +3297,54 @@ or of the entire buffer, if the region i
 (defvar rst-pdf-program "xpdf"
   "Program used to preview PDF files.")
 
+(if (> emacs-major-version 22)
+    (defalias 'rst--make-temp-file 'make-temp-file)
+  (defvar temporary-file-directory)
+  (defun rst--make-temp-file (prefix &optional dir-flag suffix)
+  "Create a temporary file.
+The returned file name (created by appending some random characters at the end
+of PREFIX, and expanding against `temporary-file-directory' if necessary),
+is guaranteed to point to a newly created empty file.
+You can then use `write-region' to write new data into the file.
+
+If DIR-FLAG is non-nil, create a new empty directory instead of a file.
+
+If SUFFIX is non-nil, add that at the end of the file name."
+  (let ((umask (default-file-modes))
+	file)
+    (unwind-protect
+	(progn
+	  ;; Create temp files with strict access rights.  It's easy to
+	  ;; loosen them later, whereas it's impossible to close the
+	  ;; time-window of loose permissions otherwise.
+	  (set-default-file-modes ?\700)
+	  (while (condition-case ()
+		     (progn
+		       (setq file
+			     (make-temp-name
+				(if (zerop (length prefix))
+				    (file-name-as-directory
+				  temporary-file-directory)
+				(expand-file-name prefix
+						  temporary-file-directory))))
+		       (if suffix
+			   (setq file (concat file suffix)))
+		       (if dir-flag
+			   (make-directory file)
+			 (write-region "" nil file nil 'silent nil 'excl))
+		       nil)
+		   (file-already-exists t))
+	    ;; the file was somehow created by someone else between
+	    ;; `make-temp-name' and `write-region', let's try again.
+	    nil)
+	  file)
+      ;; Reset the umask.
+      (set-default-file-modes umask)))))
+
 (defun rst-compile-pdf-preview ()
   "Convert the document to a PDF file and launch a preview program."
   (interactive)
-  (let* ((tmp-filename "/tmp/out.pdf")
+  (let* ((tmp-filename (rst--make-temp-file "rst" nil ".pdf"))
 	 (command (format "rst2pdf.py %s %s && %s %s"
 			  buffer-file-name tmp-filename
 			  rst-pdf-program tmp-filename)))
@@ -3315,7 +3359,7 @@ or of the entire buffer, if the region i
 (defun rst-compile-slides-preview ()
   "Convert the document to an S5 slide presentation and launch a preview program."
   (interactive)
-  (let* ((tmp-filename "/tmp/slides.html")
+  (let* ((tmp-filename (rst--make-temp-file "rst" nil ".html"))
 	 (command (format "rst2s5.py %s %s && %s %s"
 			  buffer-file-name tmp-filename
 			  rst-slides-program tmp-filename)))