I have just spent a week reverse-engineering this, so I thought I'd contribute the work back to the community
diff --git a/doc/uImage.FIT/signature.txt b/doc/uImage.FIT/signature.txt index 61a72db3c7..61cdd55e40 100644 --- a/doc/uImage.FIT/signature.txt +++ b/doc/uImage.FIT/signature.txt @@ -382,6 +382,25 @@ verified later even if the FIT has been signed with other keys in the meantime.
+Details +------- +The signature node contains a property ('hashed-nodes') which lists all the +nodes that the signature was made over. The image is walked in order and each +tag processed as follows: +- DTB_BEGIN_NODE: The tag and the following name are added to the signature if + the node or its parent are present in 'hashed-nodes' +- DTB_END_NODE: The tag is added to the signature if the node or its parent are + present in 'hashed-nodes' +- DTB_PROPERTY: The tag, the length word, the offset in the string table, and + the data are all included if the node is present in 'hashed-nodes' and the + property name is not 'data'. +- DTB_END: The tag is always included. + +In addition, the signature contains a property 'hashed-strings' which contains +the offset and length in the string table of the strings that are to be added +to the signature (this is always done at the end). + + Verification ------------ FITs are verified when loaded. After the configuration is selected a list