Mercurial > hg > octave-nkf > gnulib-hg
changeset 8059:5cac1cb7921e
* lib/mkdir-p.c (make_dir_parents): Close a race condition that
occurs when "mkdir -m foo" creates a setgid directory that is (1)
writeable to group or other and (2) is intended to have a special
mode bit that is set or cleared. In such a case, the directory
should be neither group- nor other-writeable until the special
mode bits are right.
author | Paul Eggert <eggert@cs.ucla.edu> |
---|---|
date | Thu, 01 Feb 2007 07:56:15 +0000 |
parents | 1a9bc966d0af |
children | aa9210dfec71 |
files | ChangeLog lib/mkdir-p.c |
diffstat | 2 files changed, 23 insertions(+), 9 deletions(-) [+] |
line wrap: on
line diff
--- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,12 @@ +2007-01-31 Paul Eggert <eggert@cs.ucla.edu> + + * lib/mkdir-p.c (make_dir_parents): Close a race condition that + occurs when "mkdir -m foo" creates a setgid directory that is (1) + writeable to group or other and (2) is intended to have a special + mode bit that is set or cleared. In such a case, the directory + should be neither group- nor other-writeable until the special + mode bits are right. + 2007-01-31 Eric Blake <ebb9@byu.net> * modules/mountlist (Depends-on): Add strstr
--- a/lib/mkdir-p.c +++ b/lib/mkdir-p.c @@ -1,7 +1,7 @@ /* mkdir-p.c -- Ensure that a directory and its parents exist. - Copyright (C) 1990, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005, 2006 - Free Software Foundation, Inc. + Copyright (C) 1990, 1997, 1998, 1999, 2000, 2002, 2003, 2004, 2005, + 2006, 2007 Free Software Foundation, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by @@ -115,19 +115,24 @@ if (0 <= prefix_len) { - /* If the ownership will change, create the directory with + /* If the ownership might change, or if the directory will be + writeable to other users and its special mode bits may + change after the directory is created, create it with more restrictive permissions at first, so unauthorized users cannot nip in before the directory is ready. */ + bool keep_owner = owner == (uid_t) -1 && group == (gid_t) -1; + bool keep_special_mode_bits = + ((mode_bits & (S_ISUID | S_ISGID)) | (mode & S_ISVTX)) == 0; mode_t mkdir_mode = mode; - if (! (owner == (uid_t) -1 && group == (gid_t) -1)) - mkdir_mode &= S_IRWXU; + if (! keep_owner) + mkdir_mode &= ~ (S_IRWXG | S_IRWXO); + else if (! keep_special_mode_bits) + mkdir_mode &= ~ (S_IWGRP | S_IWOTH); if (mkdir (dir + prefix_len, mkdir_mode) == 0) { announce (dir, options); - preserve_existing = - (owner == (uid_t) -1 && group == (gid_t) -1 - && ! ((mode_bits & (S_ISUID | S_ISGID)) | (mode & S_ISVTX))); + preserve_existing = keep_owner & keep_special_mode_bits; savewd_chdir_options |= (SAVEWD_CHDIR_NOFOLLOW | (mode & S_IRUSR ? SAVEWD_CHDIR_READABLE : 0)); @@ -188,7 +193,7 @@ (! chdir_failed_unexpectedly ? errno : ! chdir_ok && (mode & S_IXUSR) ? chdir_errno : open_result[1]), - _(owner == (uid_t) -1 && group == (gid_t) -1 + _(keep_owner ? "cannot change permissions of %s" : "cannot change owner and permissions of %s"), quote (dir));