• Andy Whitcroft's avatar
    xfrm_user: validate XFRM_MSG_NEWAE XFRMA_REPLAY_ESN_VAL replay_window · 677e806d
    Andy Whitcroft authored
    When a new xfrm state is created during an XFRM_MSG_NEWSA call we
    validate the user supplied replay_esn to ensure that the size is valid
    and to ensure that the replay_window size is within the allocated
    buffer.  However later it is possible to update this replay_esn via a
    XFRM_MSG_NEWAE call.  There we again validate the size of the supplied
    buffer matches the existing state and if so inject the contents.  We do
    not at this point check that the replay_window is within the allocated
    memory.  This leads to out-of-bounds reads and writes triggered by
    netlink packets.  This leads to memory corruption and the potential for
    priviledge escalation.
    We already attempt to validate the incoming replay information in
    xfrm_new_ae() via xfrm_replay_verify_len().  This confirms that the user
    is not trying to change the size of the replay state buffer which
    includes the replay_esn.  It however does not check the replay_window
    remains within that buffer.  Add validation of the contained
    Signed-off-by: default avatarAndy Whitcroft <apw@canonical.com>
    Acked-by: default avatarSteffen Klassert <steffen.klassert@secunet.com>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>