Re: [PATCH RFC v2 05/11] ti: etype: x509: Add etype for x509 certificate for K3 devices

[Neha Malcom Francis <n-francis@ti.com>]

Hi Roger,

On 31/05/22 14:50, Roger Quadros wrote:
> 
> 
> On 06/05/2022 07:37, Neha Malcom Francis wrote:
>> K3 devices x509 certificate added to certain binaries that allows ROM to
> 
> what binaries?
> 
>> validate the integrity of the image. Etype that generates an x509
>> certificate depending on boot flow added.
> 
> Could you please explain in more detail as to what exactly is happening here.
> 
> What do you mean by "depending on boot flow"?
> 

I will reformat the commit messages accordingly.
>>
>> Signed-off-by: Neha Malcom Francis <n-francis@ti.com>
>> ---
>>   tools/binman/entries.rst            |  15 ++
>>   tools/binman/etype/x509_cert.py     | 248 ++++++++++++++++++++++++++++
>>   tools/binman/ftest.py               |   7 +
>>   tools/binman/test/232_x509_cert.dts |  18 ++
>>   tools/k3_gen_x509_cert.sh           |  10 +-
>>   5 files changed, 293 insertions(+), 5 deletions(-)
>>   create mode 100644 tools/binman/etype/x509_cert.py
>>   create mode 100644 tools/binman/test/232_x509_cert.dts
>>
>> diff --git a/tools/binman/entries.rst b/tools/binman/entries.rst
>> index 0c6d82fce8..dfa281e49f 100644
>> --- a/tools/binman/entries.rst
>> +++ b/tools/binman/entries.rst
>> @@ -1890,6 +1890,21 @@ and kernel are genuine.
>>   
>>   
>>   
>> +Entry: x509cert: x509 certificate for K3 devices
>> +------------------------------------------------
>> +
> 
> x509 is a generic standard. Can this be made usable by other vendors as well or
> is it very specific to TI?
> If this is TI specific then I'd suggest a "ti-" prefix to the entry name.
> 
>> +Properties / Entry arguments:
>> +        - content: Phandle of binary to sign
>> +        - output: Name of the final output file
> 
> why do you need output property?
> 

That is not required, I had later changed it to always using 
certificate.bin. Will make the necessary changes.

>> +        - key_file: File with key inside it. If not provided, script generates RSA degenerate key
>> +        - core: Target core ID on which image would be running
>> +        - load: Target load address of the binary in hex
>> +
>> +    Output files:
>> +        - certificate.bin: Signed certificate binary
>> +
>> +
>> +
>>   Entry: x86-reset16: x86 16-bit reset code for U-Boot
>>   ----------------------------------------------------
>>   
>> diff --git a/tools/binman/etype/x509_cert.py b/tools/binman/etype/x509_cert.py
>> new file mode 100644
>> index 0000000000..0009973155
>> --- /dev/null
>> +++ b/tools/binman/etype/x509_cert.py
>> @@ -0,0 +1,248 @@
>> +# SPDX-License-Identifier: GPL-2.0+
>> +# Copyright (c) 2018 Google, Inc
>> +# Written by Simon Glass <sjg@chromium.org>
>> +#
>> +
>> +# Support for a x509 certificate for signing K3 devices
>> +
>> +import os
>> +from collections import OrderedDict
>> +from subprocess import Popen, PIPE
>> +from sys import stderr, stdout
>> +
>> +import asn1
>> +from Crypto.PublicKey import RSA
>> +from cryptography.hazmat.backends import default_backend
>> +from cryptography.hazmat.primitives import serialization
>> +
>> +from binman.etype.collection import Entry_collection
>> +from dtoc import fdt_util
>> +from patman import tools
>> +
>> +temp_x509 = "x509-temp.cert"
>> +cert = "certificate.bin"
>> +rand_key = "eckey.pem"
>> +bootcore_opts = 0
>> +bootcore = 0
>> +debug_type = 0
>> +
>> +
>> +class Entry_x509_cert(Entry_collection):
>> +    """ An entry which contains a x509 certificate
>> +
>> +    Properties / Entry arguments:
>> +        - content: Phandle of binary to sign
>> +        - key_file: File with key inside it. If not provided, script generates RSA degenerate key
>> +        - core: Target core ID on which image would be running
>> +        - load: Target load address of the binary in hex
>> +
>> +    Output files:
>> +        - certificate.bin: Signed certificate binary"""
>> +
>> +    def __init__(self, section, etype, node):
>> +        super().__init__(section, etype, node)
>> +        self.key_file = fdt_util.GetString(self._node, 'key-file', "")
>> +        self.core = fdt_util.GetInt(self._node, 'core', 0)
>> +        self.load_addr = fdt_util.GetInt(self._node, 'load', 0x41c00000)
>> +
>> +    def ReadNode(self):
>> +        super().ReadNode()
>> +        if self.key_file == "":
>> +            self.degen_key = True
>> +        else:
>> +            self.degen_key = False
>> +
>> +    def _CreateCertificate(self):
>> +        """Create certificate for legacy boot flow"""
>> +        if self.degen_key == True:
>> +            gen_degen_key()
>> +            self.key_file = rand_key
>> +
>> +        sha_val = get_sha_val("intermediate-sysfw.bin")
>> +        bin_size = get_file_size("intermediate-sysfw.bin")
>> +        addr = "%08x" % self.load_addr
>> +        if self.core == 0:
>> +            cert_type = 2
>> +        elif self.core == 16:
>> +            cert_type = 1
>> +        else:
>> +            cert_type = 2
>> +        debug_type = 0
>> +
>> +        gen_template()
>> +        gen_cert(bin_size, sha_val, cert_type, bootcore_opts,
>> +                 self.core, addr, debug_type, self.key_file)
>> +
>> +        return tools.read_file("certificate.bin")
>> +
>> +    def ObtainContents(self):
>> +        self.image = self.GetContents(False)
>> +        if self.image is None:
>> +            return False
>> +        f = open("intermediate-sysfw.bin", "wb")
>> +        f.write(self.image)
>> +        f.close()
>> +        self.SetContents(self._CreateCertificate())
>> +        return True
>> +
>> +    def ProcessContents(self):
>> +        data = self._CreateCertificate()
>> +        return self.ProcessContentsUpdate(data)
> 
> Why do you need _CreateCertificate() and ProcessContents()?
> Just have one ObtainContents() and try to get rid of all the intermediate files.
> 

I used etype/vblock.py as a reference. I will clean up this etype further.

>> +
>> +
>> +def get_sha_val(binary_file):
>> +    process = Popen(['openssl', 'dgst', '-sha512', '-hex',
>> +                    binary_file], stdout=PIPE, stderr=PIPE)
>> +    stdout, stderr = process.communicate()
>> +    sha_val = stdout.split()[1]
>> +    return sha_val
>> +
>> +
>> +def get_file_size(binary_file):
>> +    return os.path.getsize(binary_file)
>> +
>> +
>> +def gen_degen_template():
>> +    with open("degen-template.txt", 'w+', encoding='utf-8') as f:
>> +        degen_temp = """
>> +asn1=SEQUENCE:rsa_key
>> +
>> +[rsa_key]
>> +version=INTEGER:0
>> +modulus=INTEGER:0xDEGEN_MODULUS
>> +pubExp=INTEGER:1
>> +privExp=INTEGER:1
>> +p=INTEGER:0xDEGEN_P
>> +q=INTEGER:0xDEGEN_Q
>> +e1=INTEGER:1
>> +e2=INTEGER:1
>> +coeff=INTEGER:0xDEGEN_COEFF"""
>> +        f.write(degen_temp)
>> +
>> +
>> +def gen_template():
>> +    """Generate x509 Template"""
>> +    with open("x509-template.txt", "w+", encoding='utf-8') as f:
>> +        x509template = """
>> +[ req ]
>> +distinguished_name     = req_distinguished_name
>> +x509_extensions        = v3_ca
>> +prompt                 = no
>> +dirstring_type         = nobmp
>> +
>> +[ req_distinguished_name ]
>> +C                      = US
>> +ST                     = TX
>> +L                      = Dallas
>> +O                      = Texas Instruments Incorporated
>> +OU                     = Processors
>> +CN                     = TI support
>> +emailAddress           = support@ti.com
>> +
>> +[ v3_ca ]
>> +basicConstraints = CA:true
>> +1.3.6.1.4.1.294.1.1 = ASN1:SEQUENCE:boot_seq
>> +1.3.6.1.4.1.294.1.2 = ASN1:SEQUENCE:image_integrity
>> +1.3.6.1.4.1.294.1.3 = ASN1:SEQUENCE:swrv
>> +# 1.3.6.1.4.1.294.1.4 = ASN1:SEQUENCE:encryption
>> +1.3.6.1.4.1.294.1.8 = ASN1:SEQUENCE:debug
>> +
>> +[ boot_seq ]
>> +certType = INTEGER:TEST_CERT_TYPE
>> +bootCore = INTEGER:TEST_BOOT_CORE
>> +bootCoreOpts = INTEGER:TEST_BOOT_CORE_OPTS
>> +destAddr = FORMAT:HEX,OCT:TEST_BOOT_ADDR
>> +imageSize = INTEGER:TEST_IMAGE_LENGTH
>> +
>> +[ image_integrity ]
>> +shaType = OID:2.16.840.1.101.3.4.2.3
>> +shaValue = FORMAT:HEX,OCT:TEST_IMAGE_SHA_VAL
>> +
>> +[ swrv ]
>> +swrv = INTEGER:0
>> +
>> +# [ encryption ]
>> +# initalVector = FORMAT:HEX,OCT:TEST_IMAGE_ENC_IV
>> +# randomString = FORMAT:HEX,OCT:TEST_IMAGE_ENC_RS
>> +# iterationCnt = INTEGER:TEST_IMAGE_KEY_DERIVE_INDEX
>> +# salt = FORMAT:HEX,OCT:TEST_IMAGE_KEY_DERIVE_SALT
>> +
>> +[ debug ]
>> +debugUID = FORMAT:HEX,OCT:0000000000000000000000000000000000000000000000000000000000000000
>> +debugType = INTEGER:TEST_DEBUG_TYPE
>> +coreDbgEn = INTEGER:0
>> +coreDbgSecEn = INTEGER:0"""
>> +        f.write(x509template)
>> +
>> +
>> +def parse_key(inp_key, section):
>> +    parsed_key = ""
>> +    section_true = False
>> +    with open(inp_key, 'r') as file:
>> +        for line in file:
>> +            if section in line:
>> +                section_true = True
>> +            elif section_true:
>> +                if "    " not in line:
>> +                    break
>> +                else:
>> +                    parsed_key += line.replace(":", "").replace("    ", "")
>> +    return parsed_key.replace("\n", "")
>> +
>> +
>> +def gen_degen_key():
>> +    """Generate a 4096 bit RSA key"""
>> +    try:
>> +        # generates 1024 bit PEM encoded RSA key in PKCS#1 format
>> +        private_key = RSA.generate(1024)
>> +        f = open('key.pem', 'wb')
>> +        f.write(private_key.exportKey('PEM'))
>> +        f.close()
>> +    except:
>> +        raise(Exception)
>> +
>> +    try:
>> +        process = Popen(['openssl', 'rsa', '-in', 'key.pem',
>> +                        '-text', '-out', 'key.txt'], stdout=PIPE, stderr=PIPE)
>> +        stdout, stderr = process.communicate()
>> +    except:
>> +        raise(stderr)
>> +
>> +    DEGEN_MODULUS = parse_key("key.txt", "modulus")
>> +    DEGEN_P = parse_key("key.txt", "prime1")
>> +    DEGEN_Q = parse_key("key.txt", "prime2")
>> +    DEGEN_COEFF = parse_key("key.txt", "coefficient")
>> +
>> +    gen_degen_template()
>> +
>> +    with open("degen-template.txt", 'r') as file_input:
>> +        with open("degenerateKey.txt", 'w') as file_output:
>> +            for line in file_input:
>> +                s = line.replace("DEGEN_MODULUS", DEGEN_MODULUS).replace(
>> +                    "DEGEN_P", DEGEN_P).replace("DEGEN_Q", DEGEN_Q).replace("DEGEN_COEFF", DEGEN_COEFF)
>> +                file_output.write(s)
>> +
>> +    try:
>> +        process = Popen(['openssl', 'asn1parse', '-genconf', 'degenerateKey.txt',
>> +                        '-out', 'degenerateKey.der'], stdout=PIPE, stderr=PIPE)
>> +        stdout, stderr = process.communicate()
>> +    except:
>> +        raise(stderr)
>> +
>> +    try:
>> +        process = Popen(['openssl', 'rsa', '-in', 'degenerateKey.der',
>> +                        '-inform', 'DER', '-outform', 'PEM', '-out', rand_key])
>> +        stdout, stderr = process.communicate()
>> +    except:
>> +        raise(stderr)
>> +
>> +
>> +def gen_cert(bin_size, sha_val, cert_type, bootcore_opts, bootcore, addr, debug_type, key):
>> +    with open(temp_x509, "w") as output_file:
>> +        with open("x509-template.txt", "r") as input_file:
>> +            for line in input_file:
>> +                output_file.write(line.replace("TEST_IMAGE_LENGTH", str(bin_size)).replace("TEST_IMAGE_SHA_VAL", sha_val.decode("utf-8")).replace("TEST_CERT_TYPE", str(cert_type)).replace(
>> +                    "TEST_BOOT_CORE_OPTS", str(bootcore_opts)).replace("TEST_BOOT_CORE", str(bootcore)).replace("TEST_BOOT_ADDR", str(addr)).replace("TEST_DEBUG_TYPE", str(debug_type)))
>> +    process = Popen(['openssl', 'req', '-new', '-x509', '-key', key, '-nodes', '-outform',
>> +                    'DER', '-out', cert, '-config', temp_x509, '-sha512'], stdout=PIPE, stderr=PIPE)
>> +    stdout, stderr = process.communicate()
>> diff --git a/tools/binman/ftest.py b/tools/binman/ftest.py
>> index 5ff294a386..d8ee592250 100644
>> --- a/tools/binman/ftest.py
>> +++ b/tools/binman/ftest.py
>> @@ -96,6 +96,7 @@ ENV_DATA              = b'var1=1\nvar2="2"'
>>   PRE_LOAD_MAGIC        = b'UBSH'
>>   PRE_LOAD_VERSION      = 0x11223344.to_bytes(4, 'big')
>>   PRE_LOAD_HDR_SIZE     = 0x00001000.to_bytes(4, 'big')
>> +X509_DATA             = b'filetobesigned'
>>   
>>   # Subdirectory of the input dir to use to put test FDTs
>>   TEST_FDT_SUBDIR       = 'fdts'
>> @@ -200,6 +201,7 @@ class TestFunctional(unittest.TestCase):
>>           TestFunctional._MakeInputFile('fw_dynamic.bin', OPENSBI_DATA)
>>           TestFunctional._MakeInputFile('sysfw.bin', TI_SYSFW_DATA)
>>           TestFunctional._MakeInputFile('scp.bin', SCP_DATA)
>> +        TestFunctional._MakeInputFile('tosign.bin', X509_DATA)
>>   
>>           # Add a few .dtb files for testing
>>           TestFunctional._MakeInputFile('%s/test-fdt1.dtb' % TEST_FDT_SUBDIR,
>> @@ -5537,5 +5539,10 @@ fdt         fdtmap                Extract the devicetree blob from the fdtmap
>>           data = self._DoReadFile('232_ti_sysfw.dts')
>>           self.assertEqual(TI_SYSFW_DATA, data[:len(TI_SYSFW_DATA)])
>>   
>> +    def testX509Cert(self):
>> +        """Test an image with the default x509 certificate header"""
>> +        data = self._DoReadFile('232_x509_cert.dts')
>> +        self.assertEqual(X509_DATA, data[938:938 + len(X509_DATA)])
> 
> what is 938?
> 
> Isn't it easier to just assert that _DoReadFile('232_x509_cert.dts') is greater than len(X509_DATA)?
> 
>> +
>>   if __name__ == "__main__":
>>       unittest.main()
>> diff --git a/tools/binman/test/232_x509_cert.dts b/tools/binman/test/232_x509_cert.dts
>> new file mode 100644
>> index 0000000000..f768568ca7
>> --- /dev/null
>> +++ b/tools/binman/test/232_x509_cert.dts
>> @@ -0,0 +1,18 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +
>> +/dts-v1/;
>> +
>> +/ {
>> +	#address-cells = <1>;
>> +	#size-cells = <1>;
>> +
>> +	binman {
>> +		x509-cert {
>> +			content = <&image>;
>> +		};
>> +
>> +		image: blob-ext {
>> +			filename = "tosign.bin";
>> +		};
>> +	};
>> +};
>> diff --git a/tools/k3_gen_x509_cert.sh b/tools/k3_gen_x509_cert.sh
>> index 298cec1313..b6ef5a2de3 100755
>> --- a/tools/k3_gen_x509_cert.sh
>> +++ b/tools/k3_gen_x509_cert.sh
>> @@ -109,7 +109,7 @@ gen_degen_key() {
>>   	openssl asn1parse -genconf degenerateKey.txt -out degenerateKey.der >>/dev/null 2>&1
>>   	openssl rsa -in degenerateKey.der -inform DER -outform PEM -out $RAND_KEY >>/dev/null 2>&1
>>   	KEY=$RAND_KEY
>> -	rm key.pem key.txt degen-template.txt degenerateKey.txt degenerateKey.der
>> +	#rm key.pem key.txt degen-template.txt degenerateKey.txt degenerateKey.der
>>   }
>>   
>>   declare -A options_help
>> @@ -246,7 +246,7 @@ gen_cert
>>   cat $CERT $BIN > $OUTPUT
>>   
>>   # Remove all intermediate files
>> -rm $TEMP_X509 $CERT x509-template.txt
>> -if [ "$KEY" == "$RAND_KEY" ]; then
>> -	rm $RAND_KEY
>> -fi
>> +#rm $TEMP_X509 $CERT x509-template.txt
>> +#if [ "$KEY" == "$RAND_KEY" ]; then
>> +#	rm $RAND_KEY
>> +#fi
> 
> Why these changes?
> Maybe you should include them within
> "ifndef CONFIG_BINMAN ... endif" to avoid breaking platforms not using BINMAN.
> 
> cheers,
> -roger

-- 
Thanking You
Neha Malcom Francis