1. 02 5月, 2013 7 次提交
  2. 04 3月, 2013 1 次提交
    • E
      fs: Limit sys_mount to only request filesystem modules. · 7f78e035
      Eric W. Biederman 提交于
      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: NSerge Hallyn <serge.hallyn@canonical.com>
      Acked-by: NKees Cook <keescook@chromium.org>
      Reported-by: NKees Cook <keescook@google.com>
      Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
      7f78e035
  3. 27 2月, 2013 5 次提交
  4. 26 2月, 2013 3 次提交
  5. 23 2月, 2013 2 次提交
  6. 20 2月, 2013 1 次提交
  7. 19 2月, 2013 5 次提交
  8. 14 2月, 2013 10 次提交
  9. 12 2月, 2013 4 次提交
  10. 18 1月, 2013 2 次提交
    • A
      libceph: pass length to ceph_calc_file_object_mapping() · e8afad65
      Alex Elder 提交于
      ceph_calc_file_object_mapping() takes (among other things) a "file"
      offset and length, and based on the layout, determines the object
      number ("bno") backing the affected portion of the file's data and
      the offset into that object where the desired range begins.  It also
      computes the size that should be used for the request--either the
      amount requested or something less if that would exceed the end of
      the object.
      
      This patch changes the input length parameter in this function so it
      is used only for input.  That is, the argument will be passed by
      value rather than by address, so the value provided won't get
      updated by the function.
      
      The value would only get updated if the length would surpass the
      current object, and in that case the value it got updated to would
      be exactly that returned in *oxlen.
      
      Only one of the two callers is affected by this change.  Update
      ceph_calc_raw_layout() so it records any updated value.
      Signed-off-by: NAlex Elder <elder@inktank.com>
      Reviewed-by: NJosh Durgin <josh.durgin@inktank.com>
      e8afad65
    • Y
      ceph: check mds_wanted for imported cap · 390306c3
      Yan, Zheng 提交于
      The MDS may have incorrect wanted caps after importing caps. So the
      client should check the value mds has and send cap update if necessary.
      Signed-off-by: NYan, Zheng <zheng.z.yan@intel.com>
      Reviewed-by: NSage Weil <sage@inktank.com>
      390306c3