tools: binman: add 'fit, encrypt' property to pass keys directory to mkimage

mkimage can be used for both signing the FIT or encrypt its content and the
option '-k' can be used to pass a directory where both signing and encryption
keys can be retrieved. Adding 'fit,encrypt' property to the 'fit' node, leads to
try to find keys directory among binman include directories.
_get_priv_keys_dir() is renamed as _get_keys_dir() and adapted to support both
signing and encryption nodes in the FIT.

Signed-off-by: Paul HENRYS <paul.henrys_ext@softathome.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

tools/binman/btool/mkimage.py

@@ -22,7 +22,7 @@ class Bintoolmkimage(bintool.Bintool):
 
     # pylint: disable=R0913
     def run(self, reset_timestamp=False, output_fname=None, external=False,
-            pad=None, align=None, priv_keys_dir=None):
+            pad=None, align=None, keys_dir=None):
         """Run mkimage
 
         Args:
@@ -34,7 +34,7 @@ class Bintoolmkimage(bintool.Bintool):
                 other things to be easily added later, if required, such as
                 signatures
             align: Bytes to use for alignment of the FIT and its external data
-            priv_keys_dir: Path to directory containing private keys
+            keys_dir: Path to directory containing private and encryption keys
             version: True to get the mkimage version
         """
         args = []
@@ -46,8 +46,8 @@ class Bintoolmkimage(bintool.Bintool):
             args += ['-B', f'{align:x}']
         if reset_timestamp:
             args.append('-t')
-        if priv_keys_dir:
-            args += ['-k', f'{priv_keys_dir}']
+        if keys_dir:
+            args += ['-k', f'{keys_dir}']
         if output_fname:
             args += ['-F', output_fname]
         return self.run_cmd(*args)

tools/binman/entries.rst

@@ -871,6 +871,13 @@ The top-level 'fit' node supports the following special properties:
         -k flag. All the keys required for signing FIT must be available at
         time of signing and must be located in single include directory.
 
+    fit,encrypt
+        Enable data encryption in FIT images via mkimage. If the property
+        is found, the keys path is detected among binman include
+        directories and passed to mkimage via  -k flag. All the keys
+        required for encrypting the FIT must be available at the time of
+        encrypting and must be located in a single include directory.
+
 Substitutions
 ~~~~~~~~~~~~~
 

tools/binman/etype/fit.py

@@ -110,6 +110,13 @@ class Entry_fit(Entry_section):
             available at time of signing and must be located in single include
             directory.
 
+        fit,encrypt
+            Enable data encryption in FIT images via mkimage. If the property
+            is found, the keys path is detected among binman include
+            directories and passed to mkimage via  -k flag. All the keys
+            required for encrypting the FIT must be available at the time of
+            encrypting and must be located in a single include directory.
+
     Substitutions
     ~~~~~~~~~~~~~
 
@@ -518,14 +525,14 @@ class Entry_fit(Entry_section):
         # are removed from self._entries later.
         self._priv_entries = dict(self._entries)
 
-    def _get_priv_keys_dir(self, data):
-        """Detect private keys path among binman include directories
+    def _get_keys_dir(self, data):
+        """Detect private and encryption keys path among binman include directories
 
         Args:
             data: FIT image in binary format
 
         Returns:
-            str: Single path containing all private keys found or None
+            str: Single path containing all keys found or None
 
         Raises:
             ValueError: Filename 'rsa2048.key' not found in input path
@@ -533,11 +540,14 @@ class Entry_fit(Entry_section):
         """
         def _find_keys_dir(node):
             for subnode in node.subnodes:
-                if subnode.name.startswith('signature'):
+                if (subnode.name.startswith('signature') or
+                    subnode.name.startswith('cipher')):
                     if subnode.props.get('key-name-hint') is None:
                         continue
                     hint = subnode.props['key-name-hint'].value
-                    name = tools.get_input_filename(f"{hint}.key")
+                    name = tools.get_input_filename(
+                        f"{hint}.key" if subnode.name.startswith('signature')
+                        else f"{hint}.bin")
                     path = os.path.dirname(name)
                     if path not in paths:
                         paths.append(path)
@@ -587,8 +597,9 @@ class Entry_fit(Entry_section):
         align = self._fit_props.get('fit,align')
         if align is not None:
             args.update({'align': fdt_util.fdt32_to_cpu(align.value)})
-        if self._fit_props.get('fit,sign') is not None:
-            args.update({'priv_keys_dir': self._get_priv_keys_dir(data)})
+        if (self._fit_props.get('fit,sign') is not None or
+            self._fit_props.get('fit,encrypt') is not None):
+            args.update({'keys_dir': self._get_keys_dir(data)})
         if self.mkimage.run(reset_timestamp=True, output_fname=output_fname,
                             **args) is None:
             if not self.GetAllowMissing():