docs(threat-model): revamp threat #9
Reword the description of threat #9 to make it more future-proof for
Arm CCA. By avoiding specific references to secure or non-secure
contexts, in favour of "worlds" and "security contexts", we make the
description equally applicable to 2-world and 4-world architectures.
Note that there are other threats that would benefit from such a
similar revamp but this is out of scope of this patch.
Also list malicious secure world code as a potential threat
agent. This seems to be an oversight in the first version of the
threat model (i.e. this change is not related to Arm CCA).
Change-Id: Id8c8424b0a801104c4f3dc70e344ee702d2b259a
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
diff --git a/docs/threat_model/threat_model.rst b/docs/threat_model/threat_model.rst
index 611e8a1..86b2134 100644
--- a/docs/threat_model/threat_model.rst
+++ b/docs/threat_model/threat_model.rst
@@ -617,19 +617,18 @@
| Threat | | **Improperly handled SMC calls can leak register |
| | contents** |
| | |
-| | | When switching between secure and non-secure |
-| | states, register contents of Secure world or |
-| | register contents of other normal world clients |
-| | can be leaked. |
+| | | When switching between worlds, TF-A register state |
+| | can leak to software in different security |
+| | contexts. |
+------------------------+------------------------------------------------------+
-| Diagram Elements | DF5 |
+| Diagram Elements | DF4, DF5 |
+------------------------+------------------------------------------------------+
| Affected TF-A | BL31 |
| Components | |
+------------------------+------------------------------------------------------+
| Assets | Sensitive Data |
+------------------------+------------------------------------------------------+
-| Threat Agent | NSCode |
+| Threat Agent | NSCode, SecCode |
+------------------------+------------------------------------------------------+
| Threat Type | Information Disclosure |
+------------------------+-------------------+----------------+-----------------+