--- Begin Message ---
Subject: |
auto-save permissions race condition |
Date: |
Thu, 29 Dec 2011 12:55:29 -0800 |
User-agent: |
Mozilla/5.0 (X11; Linux i686; rv:8.0) Gecko/20111124 Thunderbird/8.0 |
Tags: patch
This closes a minor security hole.
=== modified file 'src/ChangeLog'
--- src/ChangeLog 2011-12-28 07:55:49 +0000
+++ src/ChangeLog 2011-12-29 20:44:31 +0000
@@ -1,3 +1,15 @@
+2011-12-29 Paul Eggert <address@hidden>
+
+ emacs: fix an auto-save permissions race condition
+ * fileio.c (auto_saving_dir_umask): New static var.
+ (Fmake_directory_internal): Use it.
+ (do_auto_save_make_dir): Set it, instead of invoking chmod after
+ creating the directory. The old code temporarily assigns
+ too-generous permissions to the directory.
+ (do_auto_save_eh): Clear it.
+ (Fdo_auto_save): Catch all errors, not just file errors, so
+ that the var is always cleared.
+
2011-12-28 Kenichi Handa <address@hidden>
* coding.c (Fdefine_coding_system_internal): Make an utf-8 base
=== modified file 'src/fileio.c'
--- src/fileio.c 2011-12-17 17:00:49 +0000
+++ src/fileio.c 2011-12-29 20:44:31 +0000
@@ -90,6 +90,9 @@
/* Nonzero during writing of auto-save files */
static int auto_saving;
+/* Nonzero umask during creation of auto-save directories */
+static int auto_saving_dir_umask;
+
/* Set by auto_save_1 to mode of original file so Fwrite_region will create
a new file with the same mode as the original */
static int auto_save_mode_bits;
@@ -2062,7 +2065,7 @@
#ifdef WINDOWSNT
if (mkdir (dir) != 0)
#else
- if (mkdir (dir, 0777) != 0)
+ if (mkdir (dir, 0777 & ~auto_saving_dir_umask) != 0)
#endif
report_file_error ("Creating directory", list1 (directory));
@@ -5205,16 +5208,18 @@
static Lisp_Object
do_auto_save_make_dir (Lisp_Object dir)
{
- Lisp_Object mode;
+ Lisp_Object result;
- call2 (Qmake_directory, dir, Qt);
- XSETFASTINT (mode, 0700);
- return Fset_file_modes (dir, mode);
+ auto_saving_dir_umask = 077;
+ result = call2 (Qmake_directory, dir, Qt);
+ auto_saving_dir_umask = 0;
+ return result;
}
static Lisp_Object
do_auto_save_eh (Lisp_Object ignore)
{
+ auto_saving_dir_umask = 0;
return Qnil;
}
@@ -5282,7 +5287,7 @@
dir = Ffile_name_directory (listfile);
if (NILP (Ffile_directory_p (dir)))
internal_condition_case_1 (do_auto_save_make_dir,
- dir, Fcons (Fcons (Qfile_error, Qnil),
Qnil),
+ dir, Qt,
do_auto_save_eh);
UNGCPRO;
}
--- End Message ---