1. 01 May, 2013 1 commit
  2. 18 Apr, 2013 1 commit
  3. 17 Apr, 2013 10 commits
  4. 04 Mar, 2013 1 commit
    • Eric W. Biederman's avatar
      fs: Limit sys_mount to only request filesystem modules. · 7f78e035
      Eric W. Biederman authored
      
      
      Modify the request_module to prefix the file system type with "fs-"
      and add aliases to all of the filesystems that can be built as modules
      to match.
      
      A common practice is to build all of the kernel code and leave code
      that is not commonly needed as modules, with the result that many
      users are exposed to any bug anywhere in the kernel.
      
      Looking for filesystems with a fs- prefix limits the pool of possible
      modules that can be loaded by mount to just filesystems trivially
      making things safer with no real cost.
      
      Using aliases means user space can control the policy of which
      filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
      with blacklist and alias directives.  Allowing simple, safe,
      well understood work-arounds to known problematic software.
      
      This also addresses a rare but unfortunate problem where the filesystem
      name is not the same as it's module name and module auto-loading
      would not work.  While writing this patch I saw a handful of such
      cases.  The most significant being autofs that lives in the module
      autofs4.
      
      This is relevant to user namespaces because we can reach the request
      module in get_fs_type() without having any special permissions, and
      people get uncomfortable when a user specified string (in this case
      the filesystem type) goes all of the way to request_module.
      
      After having looked at this issue I don't think there is any
      particular reason to perform any filtering or permission checks beyond
      making it clear in the module request that we want a filesystem
      module.  The common pattern in the kernel is to call request_module()
      without regards to the users permissions.  In general all a filesystem
      module does once loaded is call register_filesystem() and go to sleep.
      Which means there is not much attack surface exposed by loading a
      filesytem module unless the filesystem is mounted.  In a user
      namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
      which most filesystems do not set today.
      Acked-by: default avatarSerge Hallyn <serge.hallyn@canonical.com>
      Acked-by: default avatarKees Cook <keescook@chromium.org>
      Reported-by: default avatarKees Cook <keescook@google.com>
      Signed-off-by: default avatar"Eric W. Biederman" <ebiederm@xmission.com>
      7f78e035
  5. 27 Feb, 2013 1 commit
  6. 26 Feb, 2013 1 commit
  7. 23 Feb, 2013 1 commit
  8. 07 Feb, 2013 1 commit
    • Eric Wong's avatar
      fuse: allow control of adaptive readdirplus use · 634734b6
      Eric Wong authored
      
      
      For some filesystems (e.g. GlusterFS), the cost of performing a
      normal readdir and readdirplus are identical.  Since adaptively
      using readdirplus has no benefit for those systems, give
      users/filesystems the option to control adaptive readdirplus use.
      
      v2 of this patch incorporates Miklos's suggestion to simplify the code,
      as well as improving consistency of macro names and documentation.
      Signed-off-by: default avatarEric Wong <normalperson@yhbt.net>
      Signed-off-by: default avatarMiklos Szeredi <mszeredi@suse.cz>
      634734b6
  9. 04 Feb, 2013 3 commits
  10. 31 Jan, 2013 2 commits
  11. 24 Jan, 2013 13 commits
  12. 17 Jan, 2013 5 commits