1. 22 Jul, 2010 1 commit
    • David Howells's avatar
      CIFS: Fix a malicious redirect problem in the DNS lookup code · 4c0c03ca
      David Howells authored
      Fix the security problem in the CIFS filesystem DNS lookup code in which a
      malicious redirect could be installed by a random user by simply adding a
      result record into one of their keyrings with add_key() and then invoking a
      CIFS CFS lookup [CVE-2010-2524].
      This is done by creating an internal keyring specifically for the caching of
      DNS lookups.  To enforce the use of this keyring, the module init routine
      creates a set of override credentials with the keyring installed as the thread
      keyring and instructs request_key() to only install lookup result keys in that
      The override is then applied around the call to request_key().
      This has some additional benefits when a kernel service uses this module to
      request a key:
       (1) The result keys are owned by root, not the user that caused the lookup.
       (2) The result keys don't pop up in the user's keyrings.
       (3) The result keys don't come out of the quota of the user that caused the
      The keyring can be viewed as root by doing cat /proc/keys:
      2a0ca6c3 I-----     1 perm 1f030000     0     0 keyring   .dns_resolver: 1/4
      It can then be listed with 'keyctl list' by root.
      	# keyctl list 0x2a0ca6c3
      	1 key in keyring:
      	726766307: --alswrv     0     0 dns_resolver: foo.bar.com
      Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
      Reviewed-and-Tested-by: default avatarJeff Layton <jlayton@redhat.com>
      Acked-by: default avatarSteve French <smfrench@gmail.com>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  2. 21 Jul, 2010 10 commits
  3. 20 Jul, 2010 29 commits