tree b5007b7e8b9afe6818a0ba448eaca9d0a72745e8
parent efbe9f2c5593ab616413713d86a0c417945ccbd6
author Robb Glasser <rglasser@google.com> 1490167771 +0000
committer Bertolin, PierreX <pierrex.bertolin@intel.com> 1493198518 -0700

xfrm_user: validate XFRM_MSG_NEWAE XFRMA_REPLAY_ESN_VAL replay_window

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
replay_window.

CVE-2017-7184

Change-Id: Ia78d7a568e3027abc7de72186452993f06e1b807
Tracked-On: https://jira01.devtools.intel.com/browse/AW-5093
Signed-off-by: Andy Whitcroft <apw@canonical.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Reviewed-on: https://android.intel.com/577971
Reviewed-by: Louis, FabienX <fabienx.louis@intel.com>
Tested-by: Louis, FabienX <fabienx.louis@intel.com>
Reviewed-by: Dubray, SimonX <simonx.dubray@intel.com>
Reviewed-by: Tasayco Loarte, VictorX <victorx.tasayco.loarte@intel.com>