Hi Christian,
On Tue, 11 Jul 2023 at 08:58, Taedcke, Christian christian.taedcke-oss@weidmueller.com wrote:
Hello Jonas,
On 10.07.2023 12:48, Jonas Karlman wrote:
Hi Christian,
On 2023-07-10 11:25, christian.taedcke-oss@weidmueller.com wrote:
From: Christian Taedcke christian.taedcke@weidmueller.com
This adds a new etype encrypted that is derived from collection.
It creates a new cipher node in the related image similar to the cipher node used by u-boot, see boot/image-cipher.c.
Signed-off-by: Christian Taedcke christian.taedcke@weidmueller.com
(no changes since v3)
Changes in v3:
- rebase on u-boot-dm/mkim-working
- update doc for functions ObtainContents and ProcessContents
- update entries.rst
Changes in v2:
add entry documentation
remove global /cipher node
replace key-name-hint with key-source property
tools/binman/entries.rst | 88 ++++++++++++++++++ tools/binman/etype/encrypted.py | 157 ++++++++++++++++++++++++++++++++ 2 files changed, 245 insertions(+) create mode 100644 tools/binman/etype/encrypted.py
diff --git a/tools/binman/entries.rst b/tools/binman/entries.rst index b55f424620..d4bc5de1d3 100644 --- a/tools/binman/entries.rst +++ b/tools/binman/entries.rst @@ -468,6 +468,94 @@ updating the EC on startup via software sync.
+.. _etype_encrypted:
+Entry: encrypted: Externally built encrypted binary blob +--------------------------------------------------------
+This entry provides the functionality to include information about how to +decrypt an encrypted binary. This information is added to the +resulting device tree by adding a new cipher node in the entry's parent +node (i.e. the binary).
+The key that must be used to decrypt the binary is either directly embedded +in the device tree or indirectly by specifying a key source. The key source +can be used as an id of a key that is stored in an external device.
+Using an embedded key +~~~~~~~~~~~~~~~~~~~~~
+This is an example using an embedded key::
- encrypted_blob: blob-ext {
filename = "encrypted-blob.bin";- };
- encrypted {
content = <&encrypted_blob>;Why is this content reference needed?
It does not look like this content is used by the etype and if the etype intends to encrypt the content this etype should probably be a section and wrap content nodes instead of referencing it.
If the content is not intended to be encrypted by this etype the name of the etype is misleading, cipher may be a better name if the intended use is to produce a cipher node for an already encrypted blob.
I tried renaming the etype to cipher, but this leads to further complications. After renaming the etype to cipher, the node cipher in the device tree has basically two different states/meanings. Initially it contains the input to binman, so binman passes the node and its properties to the etype, so the etype can evaluate it. After this is done the cipher node contains new, different properties that should not be evaluated by binman again, but simply written out to the generated device tree. But since binman does not simply parse the device tree once and writes out the result, i get an error when binman tries to pass the generated cipher node (containing the new properties that should end up in the resulting device tree) to the cipher etype again.
So in the next version of the patch series i would keep the etype name encrypted.
Could you please post the error you get? Binman should not process the nodes more than once. I might be able to fix it.
Regards, Simon