Re: [PATCH 1/3] binman: add sign option for binman

7 Sep 2022

Hi Ivan,
On Tue, 6 Sept 2022 at 07:27, Ivan Mikhaylov fr0st61te@gmail.com wrote:
...
On Thu, 2022-04-07 at 01:22 +0300, Alper Nebi Yasak wrote:
...
On 06/04/2022 23:28, Ivan Mikhaylov wrote:
...
On Tue, 2022-04-05 at 21:54 +0300, Alper Nebi Yasak wrote:
...
On 22/03/2022 00:43, Ivan Mikhaylov wrote:
...
Introduce proof of concept for binman's new option which
provides
sign
and replace sections in binary images.
Usage as example:
from:
mkimage -G privateky -r -o sha256,rsa4096 -F fit
binman replace -i flash.bin -f fit.fit fit
to:
binman sign -i flash.bin -k privatekey -a sha256,rsa4096 -f
fit.fit
fit
This shouldn't need the fit.fit input. It can be extracted from
the
image as you said in the cover letter. But I think instead of
doing
"extract -> sign with mkimage -> replace", signing should be
implemented
in the entry types as a new method. This way we can support other
entry-specific ways to sign things (see vblock for an example).
I have both of these things already:
1.extract->sign->replace
  binman sign -i flash.bin -k privatekey -a sha256,rsa4096 fit
2.sign->replace
  binman sign -i flash.bin -k privatekey -a sha256,rsa4096 -f
fit.fit
fit
Just waited for review to see in which direction should I move.
I've the case when I need only FIT image sign and replace after
that. I
think they both fit in 'sign' option. Okay about new method, so we
talking about just one call like 'SignEntries' without mkimage and
other steps with tools?
See below...
...
...
...
Signed-off-by: Ivan Mikhaylov ivan.mikhaylov@siemens.com
tools/binman/cmdline.py | 13 +++++++++++++
 tools/binman/control.py | 26 +++++++++++++++++++++++++-
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/tools/binman/cmdline.py b/tools/binman/cmdline.py
index 0626b850f4..1a25f95ff1 100644
--- a/tools/binman/cmdline.py
+++ b/tools/binman/cmdline.py
@@ -160,6 +160,19 @@ controlled by a description in the board
device tree.'''
     replace_parser.add_argument('paths', type=str, nargs='*',
                                 help='Paths within file to
replace
(wildcard)')

sign_parser = subparsers.add_parser('sign',
                                      help='Sign entries



in
image')

sign_parser.add_argument('-a', '--algo', type=str,

required=True,

                           help='Hash algorithm e.g.



sha256,rsa4096')

sign_parser.add_argument('-f', '--file', type=str,

required=True,

                           help='Input filename to sign')


sign_parser.add_argument('-i', '--image', type=str,

required=True,

                           help='Image filename to



update')

sign_parser.add_argument('-k', '--key', type=str,

required=True,

                           help='Private key file for



signing')

sign_parser.add_argument('paths', type=str, nargs='*',
                           help='Paths within file to



sign
(wildcard)')



If we want to support signing entry types other than FIT, I guess
we
need to base things on "EntryArg"s to make the arguments more
dynamic,
like named-by-arg blobs do.
Should we care about such possibility in terms of these patches?
There's already vblock and pre-load entry types where 'sign' is a
valid
thing to do. If we add a 'binman sign', it's reasonable to expect it
to
work on those as well. But these 'algo' and 'key' arguments don't
directly apply to vblock, its signing interface is a bit weird and
needs
different arguments.
Personally, I'm not sure if I'd use 'binman sign' as I like to
clean-build things, so the argument mismatch is not that big of a
concern for me.
...
...
...
 test_parser = subparsers.add_parser('test', help='Run

tests')
     test_parser.add_argument('-P', '--processes', type=int,
         help='set number of processes to use for running
tests')
diff --git a/tools/binman/control.py b/tools/binman/control.py
index a179f78129..7595ea7776 100644
--- a/tools/binman/control.py
+++ b/tools/binman/control.py
@@ -19,6 +19,7 @@ from binman import cbfs_util
 from binman import elf
 from patman import command
 from patman import tout
+from patman import tools
# List of images we plan to create
 # Make this global so that it can be referenced from tests
@@ -434,6 +435,26 @@ def ReplaceEntries(image_fname,
input_fname,
indir, entry_paths,
     AfterReplace(image, allow_resize=allow_resize,
write_map=write_map)
     return image
+def MkimageSign(privatekey_fname, algo, input_fname):

tools.Run('mkimage', '-G', privatekey_fname, '-r', '-o',

algo,
'-F', input_fname)



+def SignEntries(image_fname, input_fname, privatekey_fname,
algo,
entry_paths):

"""Sign and replace the data from one or more entries from

input files


Args:
   image_fname: Image filename to process


   input_fname: Single input filename to use if replacing



one
file, None

       otherwise


   algo: Hashing algorithm


   privatekey_fname: Private key filename



Returns:
   List of EntryInfo records that were signed and



replaced

"""

MkimageSign(privatekey_fname, algo, input_fname)

return ReplaceEntries(image_fname, input_fname, None,

entry_paths)
I wrote a bit above, but what I mean is the mkimage call would go
into a
new method in etype/fit.py, and SignEntries() would be something
like
ReplaceEntries() but end up calling that method instead of
WriteData().
Yeap, I agree, as I said above about 'how it should be'. Do you
think
it should be like additional implementation for mkimage in
etype/fit.py
which should be used in SignEntries inside? Something like:
def SignEntries(params):
        fit = SignFIT(params)
        return ReplaceEntries(params with fit)
Don't call ReplaceEntries(). Try to copy what it does, but don't call
entry.WriteData() either. Replacing FIT sections is broken on master
for
now, it tries to rebuild itself to the original specification. I'm
planning to fix it, but the way I'm thinking of is demoting the entry
to
'blob-ext' when replaced. It wouldn't be nice if that happened also
when
we're signing an entry.
I think SignEntries would be more like (untested):
def SignEntries(image_fname, entry_paths, ...):
    image_fname = os.path.abspath(image_fname)
    image = Image.FromFile(image_fname)
    state.PrepareFromLoadedData(image)
    image.LoadData()
for entry_path in entry_paths:
    entry = image.FindEntryPath(entry_path)
    entry.UpdateSignatures(...)  # TODO

ProcessImage(image, update_fdt=True, write_map=False,
             get_contents=False, allow_resize=False)


Then you'd implement UpdateSignatures in fit.py to configure the
entry
to use the given params. I'm not sure how exactly, I thought you'd
call
mkimage there, but it might be necessary to edit the underlying
binman
control dtb to change the signature nodes.
Alper, this way works but until 74d3b231(binman: Create FIT subentries
in the FIT section, not its parent) commit. self.data or self.GetData()
is None for entry which need to be signed after this commit. Any ideas
how to get the data of fit entry?
Section data comes from the BuildSectionData() method, so you could
try calling that.
See also collect_contents_to_file()
Regards,
Simon

    

Re: [PATCH 1/3] binman: add sign option for binman

Simon Glass

Signed-off-by: Ivan Mikhaylov ivan.mikhaylov@siemens.com