From 3d6cc210660e239fdb426094e5631f5ebd03cbe8 Mon Sep 17 00:00:00 2001 From: Sandrine Bailleux Date: Thu, 12 May 2022 16:37:18 +0200 Subject: [PATCH] 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 --- docs/threat_model/threat_model.rst | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/docs/threat_model/threat_model.rst b/docs/threat_model/threat_model.rst index 611e8a108..86b21345f 100644 --- a/docs/threat_model/threat_model.rst +++ b/docs/threat_model/threat_model.rst @@ -617,19 +617,18 @@ each diagram element of the data flow diagram. | 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 | +------------------------+-------------------+----------------+-----------------+