docs(threat model): add TF-A threat model
This is the first release of the public Trusted
Firmware A class threat model. This release
provides the baseline for future updates to be
applied as required by developments to the
TF-A code base.
Signed-off-by: Zelalem Aweke <zelalem.aweke@arm.com>
Change-Id: I3c9aadc46196837679f0b1377bec9ed4fc42ff11
diff --git a/docs/resources/diagrams/plantuml/tfa_dfd.puml b/docs/resources/diagrams/plantuml/tfa_dfd.puml
new file mode 100644
index 0000000..0007911
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+/'
+ ' Copyright (c) 2021, Arm Limited. All rights reserved.
+ '
+ ' SPDX-License-Identifier: BSD-3-Clause
+ '/
+
+/'
+TF-A Data Flow Diagram
+'/
+
+@startuml
+digraph tfa_dfd {
+
+ # Arrange nodes from left to right
+ rankdir="LR"
+
+ # Allow arrows to end on cluster boundaries
+ compound=true
+
+ # Default settings for edges and nodes
+ edge [minlen=2 color="#8c1b07"]
+ node [fillcolor="#ffb866" style=filled shape=box fixedsize=true width=1.6 height=0.7]
+
+ # Nodes outside of the trust boundary
+ nsec [label="Non-secure\nClients"]
+ sec [label="Secure\nClients"]
+ dbg [label="Debug & Trace"]
+ logs [label="Logs\n(UART)"]
+ nvm [label="Non-volatile\nMemory"]
+
+ # Trust boundary cluster
+ subgraph cluster_trusted{
+ graph [style=dashed color="#f22430"]
+
+ # HW IPs cluster
+ subgraph cluster_ip{
+ label ="Hardware IPs";
+ graph [style=filled color="#000000" fillcolor="#ffd29e"]
+
+ rank="same"
+ gic [label="GIC" width=1.2 height=0.5]
+ tzc [label="TZ\nController" width=1.2 height=0.5]
+ etc [label="..." shape=none style=none height=0.5]
+ }
+
+ # TF-A cluster
+ subgraph cluster_tfa{
+ label ="TF-A";
+ graph [style=filled color="#000000" fillcolor="#faf9cd"]
+
+ bl1 [label="Boot ROM\n(BL1)" fillcolor="#ddffb3"];
+ bl2 [label="Trusted Boot\nFirmware\n(BL2)" fillcolor="#ddffb3" height=1]
+ bl31 [label="TF-A Runtime\n(BL31)" fillcolor="#ddffb3"]
+ }
+ }
+
+ # Interactions between nodes
+ nvm -> bl31 [lhead=cluster_tfa label="DF1"]
+ logs -> bl31 [dir="back" lhead=cluster_tfa label="DF2"]
+ dbg -> bl2 [dir="both" lhead=cluster_tfa label="DF3"]
+ sec -> bl2 [dir="both" lhead=cluster_tfa label="DF4"]
+ nsec -> bl1 [dir="both" lhead=cluster_tfa, label="DF5"]
+ bl2 -> tzc [dir="both" ltail=cluster_tfa lhead=cluster_ip label="DF6" minlen=1]
+}
+
+@enduml