[PATCH 0/3] *** Allow encrypting data in FIT with binman ***
The first patch 0001 is required for patch 0002 as random IV are currently only added to the FIT if the encryption key is also added to the DTB. Patch 0002 then allows to use binman to encrypt data in the FIT generated when mkimage is called by binman, when cipher information are provided.
Paul HENRYS (3): aes: Allow to store randomly generated IV in the FIT tools: binman: Add a property to pass a key directory to mkimage tools: binman: Add tests for FIT with data encrypted by mkimage
lib/aes/aes-encrypt.c | 7 +++ tools/binman/btool/mkimage.py | 5 +- tools/binman/etype/fit.py | 3 + tools/binman/ftest.py | 39 +++++++++++++ tools/binman/test/326_fit_encrypt_data.dts | 53 ++++++++++++++++++ .../test/327_fit_encrypt_data_no_key.dts | 53 ++++++++++++++++++ tools/binman/test/aes256.bin | Bin 0 -> 32 bytes tools/image-host.c | 2 +- 8 files changed, 160 insertions(+), 2 deletions(-) create mode 100644 tools/binman/test/326_fit_encrypt_data.dts create mode 100644 tools/binman/test/327_fit_encrypt_data_no_key.dts create mode 100644 tools/binman/test/aes256.bin
When the initialisation vector is randomly generated, its value shall be stored in the FIT together with the encrypted data. The changes allow to store the IV in the FIT also in the case where the key is not stored in the DTB but retrieved somewhere else at runtime.
Signed-off-by: Paul HENRYS paul.henrys_ext@softathome.com --- lib/aes/aes-encrypt.c | 7 +++++++ tools/image-host.c | 2 +- 2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/lib/aes/aes-encrypt.c b/lib/aes/aes-encrypt.c index e74e35eaa28..90e1407b4f0 100644 --- a/lib/aes/aes-encrypt.c +++ b/lib/aes/aes-encrypt.c @@ -84,6 +84,13 @@ int image_aes_add_cipher_data(struct image_cipher_info *info, void *keydest, char name[128]; int ret = 0;
+ if (!keydest && !info->ivname) { + /* At least, store the IV in the FIT image */ + ret = fdt_setprop(fit, node_noffset, "iv", + info->iv, info->cipher->iv_len); + goto done; + } + /* Either create or overwrite the named cipher node */ parent = fdt_subnode_offset(keydest, 0, FIT_CIPHER_NODENAME); if (parent == -FDT_ERR_NOTFOUND) { diff --git a/tools/image-host.c b/tools/image-host.c index 7bfc0cb6b18..03173dec5f9 100644 --- a/tools/image-host.c +++ b/tools/image-host.c @@ -535,7 +535,7 @@ fit_image_process_cipher(const char *keydir, void *keydest, void *fit, * size values * And, if needed, write the iv in the FIT file */ - if (keydest) { + if (keydest || (!keydest && !info.ivname)) { ret = info.cipher->add_cipher_data(&info, keydest, fit, node_noffset); if (ret) { fprintf(stderr,
The property 'fit,keys-directory' can be added to the configuration file passed to binman to specify a directory where keys are stored and can be used by mkimage to sign and cipher data.
Signed-off-by: Paul HENRYS paul.henrys_ext@softathome.com --- tools/binman/btool/mkimage.py | 5 ++++- tools/binman/etype/fit.py | 3 +++ 2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/tools/binman/btool/mkimage.py b/tools/binman/btool/mkimage.py index 39a4c8c1432..dbcf8daac30 100644 --- a/tools/binman/btool/mkimage.py +++ b/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): + pad=None, align=None, keys_dir=None): """Run mkimage
Args: @@ -34,6 +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 + keys_dir: directory where keys are stored version: True to get the mkimage version """ args = [] @@ -45,6 +46,8 @@ class Bintoolmkimage(bintool.Bintool): args += ['-B', f'{align:x}'] if reset_timestamp: args.append('-t') + if keys_dir: + args += ['-k', keys_dir] if output_fname: args += ['-F', output_fname] return self.run_cmd(*args) diff --git a/tools/binman/etype/fit.py b/tools/binman/etype/fit.py index 2c14b15b03c..08fc08ec767 100644 --- a/tools/binman/etype/fit.py +++ b/tools/binman/etype/fit.py @@ -460,6 +460,9 @@ 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)}) + keys_dir = self._fit_props.get('fit,keys-directory') + if keys_dir is not None: + args.update({'keys_dir': keys_dir.value}) if self.mkimage.run(reset_timestamp=True, output_fname=output_fname, **args) is None: if not self.GetAllowMissing():
Test the property 'fit,keys-directory' which, when a cipher node is present, encrypts the data stored in the FIT.
Signed-off-by: Paul HENRYS paul.henrys_ext@softathome.com --- tools/binman/ftest.py | 39 +++++++++++++ tools/binman/test/326_fit_encrypt_data.dts | 53 ++++++++++++++++++ .../test/327_fit_encrypt_data_no_key.dts | 53 ++++++++++++++++++ tools/binman/test/aes256.bin | Bin 0 -> 32 bytes 4 files changed, 145 insertions(+) create mode 100644 tools/binman/test/326_fit_encrypt_data.dts create mode 100644 tools/binman/test/327_fit_encrypt_data_no_key.dts create mode 100644 tools/binman/test/aes256.bin
diff --git a/tools/binman/ftest.py b/tools/binman/ftest.py index 8a44bc051b3..b3110550c01 100644 --- a/tools/binman/ftest.py +++ b/tools/binman/ftest.py @@ -7460,5 +7460,44 @@ fdt fdtmap Extract the devicetree blob from the fdtmap with self.assertRaises(ValueError) as e: self._DoReadFile('323_capsule_accept_revert_missing.dts')
+ def testSimpleFitEncryptedData(self): + """Test an image with a FIT containing data to be encrypted""" + data = self._DoReadFile('326_fit_encrypt_data.dts') + + fit = fdt.Fdt.FromData(data) + fit.Scan() + + # Extract the encrypted data and the IV from the FIT + node = fit.GetNode('/images/u-boot') + subnode = fit.GetNode('/images/u-boot/cipher') + data_size_unciphered = int.from_bytes(fit.GetProps(node)['data-size-unciphered'].bytes, + byteorder='big') + self.assertEqual(data_size_unciphered, len(U_BOOT_NODTB_DATA)) + + # Retrieve the key name from the FIT removing any null byte + key_name = fit.GetProps(subnode)['key-name-hint'].bytes.replace(b'\x00', b'') + with open(self.TestFile(key_name.decode('ascii') + '.bin'), 'rb') as file: + key = file.read() + iv = fit.GetProps(subnode)['iv'].bytes.hex() + enc_data = fit.GetProps(node)['data'].bytes + outdir = tools.get_output_dir() + enc_data_file = os.path.join(outdir, 'encrypted_data.bin') + tools.write_file(enc_data_file, enc_data) + data_file = os.path.join(outdir, 'data.bin') + + # Decrypt the encrypted data from the FIT and compare the data + tools.run('openssl', 'enc', '-aes-256-cbc', '-nosalt', '-d', '-in', + enc_data_file, '-out', data_file, '-K', key.hex(), '-iv', iv) + with open(data_file, 'r') as file: + dec_data = file.read() + self.assertEqual(U_BOOT_NODTB_DATA, dec_data.encode('ascii')) + + def testSimpleFitEncryptedDataMissingKey(self): + """Test an image with a FIT containing data to be encrypted but with a missing key""" + with self.assertRaises(ValueError) as e: + self._DoReadFile('327_fit_encrypt_data_no_key.dts') + + self.assertIn("Can't open file ./aes256.bin (err=2 => No such file or directory)", str(e.exception)) + if __name__ == "__main__": unittest.main() diff --git a/tools/binman/test/326_fit_encrypt_data.dts b/tools/binman/test/326_fit_encrypt_data.dts new file mode 100644 index 00000000000..3cd890063cd --- /dev/null +++ b/tools/binman/test/326_fit_encrypt_data.dts @@ -0,0 +1,53 @@ +// SPDX-License-Identifier: GPL-2.0+ + +/dts-v1/; + +/ { + #address-cells = <1>; + #size-cells = <1>; + + binman { + fit { + fit,keys-directory = "tools/binman/test"; + description = "Test a FIT with encrypted data"; + #address-cells = <1>; + + images { + u-boot { + description = "U-Boot"; + type = "firmware"; + arch = "arm64"; + os = "U-Boot"; + compression = "none"; + load = <00000000>; + entry = <00000000>; + cipher { + algo = "aes256"; + key-name-hint = "aes256"; + }; + u-boot-nodtb { + }; + }; + fdt-1 { + description = "Flattened Device Tree blob"; + type = "flat_dt"; + arch = "arm64"; + compression = "none"; + cipher { + algo = "aes256"; + key-name-hint = "aes256"; + }; + }; + }; + + configurations { + default = "conf-1"; + conf-1 { + description = "Boot U-Boot with FDT blob"; + firmware = "u-boot"; + fdt = "fdt-1"; + }; + }; + }; + }; +}; diff --git a/tools/binman/test/327_fit_encrypt_data_no_key.dts b/tools/binman/test/327_fit_encrypt_data_no_key.dts new file mode 100644 index 00000000000..b92cd2e4bd6 --- /dev/null +++ b/tools/binman/test/327_fit_encrypt_data_no_key.dts @@ -0,0 +1,53 @@ +// SPDX-License-Identifier: GPL-2.0+ + +/dts-v1/; + +/ { + #address-cells = <1>; + #size-cells = <1>; + + binman { + fit { + fit,keys-directory = "."; + description = "Test a FIT with encrypted data"; + #address-cells = <1>; + + images { + u-boot { + description = "U-Boot"; + type = "firmware"; + arch = "arm64"; + os = "U-Boot"; + compression = "none"; + load = <00000000>; + entry = <00000000>; + cipher { + algo = "aes256"; + key-name-hint = "aes256"; + }; + u-boot-nodtb { + }; + }; + fdt-1 { + description = "Flattened Device Tree blob"; + type = "flat_dt"; + arch = "arm64"; + compression = "none"; + cipher { + algo = "aes256"; + key-name-hint = "aes256"; + }; + }; + }; + + configurations { + default = "conf-1"; + conf-1 { + description = "Boot U-Boot with FDT blob"; + firmware = "u-boot"; + fdt = "fdt-1"; + }; + }; + }; + }; +}; diff --git a/tools/binman/test/aes256.bin b/tools/binman/test/aes256.bin new file mode 100644 index 0000000000000000000000000000000000000000..09b8bf6254ada5c084039f32916bc7d30233bb2c GIT binary patch literal 32 ncmXpsGBz<aGq<obNK8sjNli=7$jr*l$<50zC@d;2DJ=s4pC}7U
literal 0 HcmV?d00001
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Paul HENRYS