| 44635412 | 06-Sep-2023 |
Sandrine Bailleux <sandrine.bailleux@arm.com> |
docs(threat-model): add a threat model for TF-A with Arm CCA
Arm Confidential Compute Architecture (Arm CCA) support, underpinned by
Arm Realm Management Extension (RME) support, brings in a few imp
docs(threat-model): add a threat model for TF-A with Arm CCA
Arm Confidential Compute Architecture (Arm CCA) support, underpinned by
Arm Realm Management Extension (RME) support, brings in a few important
software and hardware architectural changes in TF-A, which warrants a
new security analysis of the code base. Results of this analysis are
captured in a new threat model document, provided in this patch.
The main changes introduced in TF-A to support Arm CCA / RME are:
- Presence of a new threat agent: realm world clients.
- Availability of Arm CCA Hardware Enforced Security (HES) to support
measured boot and trusted boot.
- Configuration of the Granule Protection Tables (GPT) for
inter-world memory protection.
This is only an initial version of the threat model and we expect to
enrich it in the future.
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
Co-authored-by: Manish Pandey <manish.pandey2@arm.com>
Change-Id: Iab84dc724df694511508f90dc76b6d469c4cccd5
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| a1e121be | 21-Aug-2023 |
Sandrine Bailleux <sandrine.bailleux@arm.com> |
docs(threat-model): classify threats by mitigating entity
The generic threat model used to list threats in no particular order.
Reorganize threats so that they are grouped by mitigating entity. For
docs(threat-model): classify threats by mitigating entity
The generic threat model used to list threats in no particular order.
Reorganize threats so that they are grouped by mitigating entity. For
example, threats mitigated by the boot firmware (i.e. BL1 and BL2) are
now clubbed together, ditto for those mitigated by the runtime EL3
firmware. Note that some generic threats apply to all firmware images
so these get grouped in their own section as well.
The motivations for this refactoring are the following:
- Clarify the scope of the threats.
In particular, as the boot firmware is typically transient, threats
applying to those images can only be exploited during a short
period of time before the runtime firmware starts.
A note has been added to this effect.
- Helping developers implement mitigations in the right place.
- Some vendors have their own solution for booting their device and
only leverage the runtime firmware from the TF-A project. Thus,
they are not interested in the threat model of TF-A's boot
firmware. Isolating the latter in a specific section helps them
focus on what is important for them.
To avoid unnecessary churn, the threats ids have been kept the same.
Signed-off-by: Sandrine Bailleux <sandrine.bailleux@arm.com>
Change-Id: Id8616fd0e4b37cd400b1ad3372beb3455234d4dc
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