[PATCH v3 11/11] binman: etype: Add xilinx_fsbl_auth etype
lukas.funke-oss at weidmueller.com
lukas.funke-oss at weidmueller.com
Tue Jul 18 13:53:19 CEST 2023
From: Lukas Funke <lukas.funke at weidmueller.com>
This adds a new etype 'xilinx-fsbl-auth'. By using this etype it is
possible to created an authenticated SPL (FSBL in Xilinx terms) for
ZynqMP boards.
The etype uses Xilinx Bootgen tools in order to transform the SPL into
a bootable image and sign the image with a given primary and secondary
public key. For more information to signing the FSBL please refer to the
Xilinx Bootgen documentation.
Here is an example of the etype in use:
spl {
filename = "boot.signed.bin";
xilinx-fsbl-auth {
psk-key-name-hint = "psk0";
ssk-key-name-hint = "ssk0";
auth-params = "ppk_select=0", "spk_id=0x00000000";
u-boot-spl-nodtb {
};
u-boot-spl-dtb {
};
};
};
For this to work the hash of the primary public key has to be fused
into the ZynqMP device and authentication (RSA_EN) has to be set.
For testing purposes: if ppk hash check should be skipped one can add
the property 'fsbl_config = "bh_auth_enable";' to the etype. However,
this should only be used for testing(!).
Signed-off-by: Lukas Funke <lukas.funke at weidmueller.com>
---
Changes in v3:
- Changed etype from entry to section
- Changed property name "psk-filename" to "psk-key-name-hint"
- Changed property name "ssk-filename" to "ssk-key-name-hint"
- Decode spl elf file instead of reading start symbol
- Improved test coverage
- Improved documentation
Changes in v2:
- Add 'keysrc-enc' property to pass down to Bootgen
- Improved documentation
- Use predictable output names for intermediated results
tools/binman/entries.rst | 71 ++++++++
tools/binman/etype/xilinx_fsbl_auth.py | 221 +++++++++++++++++++++++++
2 files changed, 292 insertions(+)
create mode 100644 tools/binman/etype/xilinx_fsbl_auth.py
diff --git a/tools/binman/entries.rst b/tools/binman/entries.rst
index c368ea8053..47af8c7226 100644
--- a/tools/binman/entries.rst
+++ b/tools/binman/entries.rst
@@ -2462,3 +2462,74 @@ may be used instead.
+.. _etype_xilinx_fsbl_auth:
+
+Entry: xilinx-fsbl-auth: Authenticated SPL for booting Xilinx ZynqMP devices
+----------------------------------------------------------------------------
+
+Properties / Entry arguments:
+ - auth-params: (Optional) Authentication parameters passed to bootgen
+ - fsbl-config: (Optional) FSBL parameters passed to bootgen
+ - keysrc-enc: (Optional) Key source when using decryption engine
+ - pmufw-filename: Filename of PMU firmware. Default: pmu-firmware.elf
+ - psk-key-name-hint: Name of primary secret key to use for signing the
+ secondardy public key. Format: .pem file
+ - ssk-key-name-hint: Name of secondardy secret key to use for signing
+ the boot image. Format: .pem file
+
+The etype is used to create an authenticated boot image for Xilinx ZynqMP
+devices. In AMD/Xilinx SoCs, two pairs of public and secret keys are used
+- primary and secondary. The function of the primary public/secret key pair
+is to authenticate the secondary public/secret key pair.
+The function of the secondary key is to sign/verify the boot image. [1]
+
+AMD/Xilinx uses the following terms for private/public keys [1]:
+
+ PSK = Primary Secret Key (Used to sign Secondary Public Key)
+ PPK = Primary Public Key (Used to verify Secondary Public Key)
+ SSK = Secondary Secret Key (Used to sign the boot image/partitions)
+ SPK = Used to verify the actual boot image
+
+The following example builds an authenticated boot image. The fuses of
+the primary public key (ppk) should be fused together with the RSA_EN flag.
+
+Example node::
+
+ spl {
+ filename = "boot.signed.bin";
+
+ xilinx-fsbl-auth {
+ psk-key-name-hint = "psk0";
+ ssk-key-name-hint = "ssk0";
+ auth-params = "ppk_select=0", "spk_id=0x00000000";
+
+ u-boot-spl-nodtb {
+ };
+ u-boot-spl-pubkey-dtb {
+ algo = "sha384,rsa4096";
+ required = "conf";
+ key-name-hint = "dev";
+ };
+ };
+ };
+
+For testing purposes, e.g. if no RSA_EN should be fused, one could add
+the "bh_auth_enable" flag in the fsbl-config field. This will skip the
+verification of the ppk fuses and boot the image, even if ppk hash is
+invalid.
+
+Example node::
+
+ xilinx-fsbl-auth {
+ psk-key-name-hint = "psk0";
+ psk-key-name-hint = "ssk0";
+ ...
+ fsbl-config = "bh_auth_enable";
+ ...
+ };
+
+[1] https://docs.xilinx.com/r/en-US/ug1283-bootgen-user-guide/Using-Authentication
+
+
+
+
diff --git a/tools/binman/etype/xilinx_fsbl_auth.py b/tools/binman/etype/xilinx_fsbl_auth.py
new file mode 100644
index 0000000000..1f85784024
--- /dev/null
+++ b/tools/binman/etype/xilinx_fsbl_auth.py
@@ -0,0 +1,221 @@
+# SPDX-License-Identifier: GPL-2.0+
+# Copyright (c) 2023 Weidmueller GmbH
+# Written by Lukas Funke <lukas.funke at weidmueller.com>
+#
+# Entry-type module for signed ZynqMP boot images (boot.bin)
+#
+
+import tempfile
+
+from collections import OrderedDict
+
+from binman import elf
+from binman.etype.section import Entry_section
+
+from dtoc import fdt_util
+
+from u_boot_pylib import tools
+from u_boot_pylib import command
+
+# pylint: disable=C0103
+class Entry_xilinx_fsbl_auth(Entry_section):
+ """Authenticated SPL for booting Xilinx ZynqMP devices
+
+ Properties / Entry arguments:
+ - auth-params: (Optional) Authentication parameters passed to bootgen
+ - fsbl-config: (Optional) FSBL parameters passed to bootgen
+ - keysrc-enc: (Optional) Key source when using decryption engine
+ - pmufw-filename: Filename of PMU firmware. Default: pmu-firmware.elf
+ - psk-key-name-hint: Name of primary secret key to use for signing the
+ secondardy public key. Format: .pem file
+ - ssk-key-name-hint: Name of secondardy secret key to use for signing
+ the boot image. Format: .pem file
+
+ The etype is used to create an authenticated boot image for Xilinx ZynqMP
+ devices. In AMD/Xilinx SoCs, two pairs of public and secret keys are used
+ - primary and secondary. The function of the primary public/secret key pair
+ is to authenticate the secondary public/secret key pair.
+ The function of the secondary key is to sign/verify the boot image. [1]
+
+ AMD/Xilinx uses the following terms for private/public keys [1]:
+
+ PSK = Primary Secret Key (Used to sign Secondary Public Key)
+ PPK = Primary Public Key (Used to verify Secondary Public Key)
+ SSK = Secondary Secret Key (Used to sign the boot image/partitions)
+ SPK = Used to verify the actual boot image
+
+ The following example builds an authenticated boot image. The fuses of
+ the primary public key (ppk) should be fused together with the RSA_EN flag.
+
+ Example node::
+
+ spl {
+ filename = "boot.signed.bin";
+
+ xilinx-fsbl-auth {
+ psk-key-name-hint = "psk0";
+ ssk-key-name-hint = "ssk0";
+ auth-params = "ppk_select=0", "spk_id=0x00000000";
+
+ u-boot-spl-nodtb {
+ };
+ u-boot-spl-pubkey-dtb {
+ algo = "sha384,rsa4096";
+ required = "conf";
+ key-name-hint = "dev";
+ };
+ };
+ };
+
+ For testing purposes, e.g. if no RSA_EN should be fused, one could add
+ the "bh_auth_enable" flag in the fsbl-config field. This will skip the
+ verification of the ppk fuses and boot the image, even if ppk hash is
+ invalid.
+
+ Example node::
+
+ xilinx-fsbl-auth {
+ psk-key-name-hint = "psk0";
+ psk-key-name-hint = "ssk0";
+ ...
+ fsbl-config = "bh_auth_enable";
+ ...
+ };
+
+ [1] https://docs.xilinx.com/r/en-US/ug1283-bootgen-user-guide/Using-Authentication
+
+ """
+ def __init__(self, section, etype, node):
+ super().__init__(section, etype, node)
+ self._auth_params = None
+ self._entries = OrderedDict()
+ self._filename = None
+ self._fsbl_config = None
+ self._keysrc_enc = None
+ self._pmufw_filename = None
+ self._psk_key_name_hint = None
+ self._ssk_key_name_hint = None
+ self.align_default = None
+ self.bootgen = None
+ self.required_props = ['psk-key-name-hint', 'ssk-key-name-hint']
+
+ def ReadNode(self):
+ """Read properties from the xilinx_fsbl_auth node"""
+ super().ReadNode()
+ self._auth_params = fdt_util.GetStringList(self._node,
+ 'auth-params')
+ self._filename = fdt_util.GetString(self._node, 'filename')
+ self._fsbl_config = fdt_util.GetStringList(self._node,
+ 'fsbl-config')
+ self._keysrc_enc = fdt_util.GetString(self._node,
+ 'keysrc-enc')
+ self._pmufw_filename = fdt_util.GetString(self._node,
+ 'pmufw-filename',
+ 'pmu-firmware.elf')
+ self._psk_key_name_hint = fdt_util.GetString(self._node,
+ 'psk-key-name-hint',
+ 'psk.pem')
+ self._ssk_key_name_hint = fdt_util.GetString(self._node,
+ 'psk-key-name-hint',
+ 'ssk.pem')
+ self.ReadEntries()
+
+ @classmethod
+ def _ToElf(cls, data, output_fname):
+ """Convert SPL object file to bootable ELF file.
+
+ Args:
+ data (bytearray): u-boot-spl-nodtb + u-boot-spl-pubkey-dtb obj file
+ data
+ output_fname (str): Filename of converted FSBL ELF file
+ """
+ platform_elfflags = {"aarch64":
+ ["-B", "aarch64", "-O", "elf64-littleaarch64"],
+ # amd64 support makes no sense for the target
+ # platform, but we include it here to enable
+ # testing on hosts
+ "x86_64":
+ ["-B", "i386", "-O", "elf64-x86-64"]
+ }
+
+ gcc, args = tools.get_target_compile_tool('cc')
+ args += ['-dumpmachine']
+ stdout = command.output(gcc, *args)
+ # split target machine triplet (arch, vendor, os)
+ arch, _, _ = stdout.split('-')
+
+ spl_elf = elf.DecodeElf(tools.read_file(
+ tools.get_input_filename('spl/u-boot-spl')), 0)
+
+ # Obj file to swap data and text section (rename-section)
+ with tempfile.NamedTemporaryFile(prefix="u-boot-spl-pubkey-",
+ suffix=".o.tmp",
+ dir=tools.get_output_dir())\
+ as tmp_obj:
+ input_objcopy_fname = tmp_obj.name
+ # Align packed content to 4 byte boundary
+ pad = bytearray(tools.align(len(data), 4) - len(data))
+ tools.write_file(input_objcopy_fname, data + pad)
+ # Final output elf file which contains a valid start address
+ with tempfile.NamedTemporaryFile(prefix="u-boot-spl-pubkey-elf-",
+ suffix=".o.tmp",
+ dir=tools.get_output_dir())\
+ as tmp_elf_obj:
+ input_ld_fname = tmp_elf_obj.name
+ objcopy, args = tools.get_target_compile_tool('objcopy')
+ args += ["--rename-section", ".data=.text",
+ "-I", "binary"]
+ args += platform_elfflags[arch]
+ args += [input_objcopy_fname, input_ld_fname]
+ command.run(objcopy, *args)
+
+ ld, args = tools.get_target_compile_tool('ld')
+ args += [input_ld_fname, '-o', output_fname,
+ "--defsym", f"_start={hex(spl_elf.entry)}",
+ "-Ttext", hex(spl_elf.entry)]
+ command.run(ld, *args)
+
+ def BuildSectionData(self, required):
+ """Pack node content, and create bootable, signed ZynqMP boot image
+
+ The method collects the content of this node (usually SPL + dtb) and
+ converts them to an ELF file. The ELF file is passed to the
+ Xilinx bootgen tool which packs the SPL ELF file together with
+ Platform Management Unit (PMU) firmware into a bootable image
+ for ZynqMP devices. The image is signed within this step.
+
+ The result is a bootable, authenticated SPL image for Xilinx ZynqMP
+ devices.
+
+ """
+ data = super().BuildSectionData(required)
+ bootbin_fname = self._filename if self._filename else \
+ tools.get_output_filename(
+ f'boot.{self.GetUniqueName()}.bin')
+
+ pmufw_elf_fname = tools.get_input_filename(self._pmufw_filename)
+ psk_fname = tools.get_input_filename(self._psk_key_name_hint + ".pem")
+ ssk_fname = tools.get_input_filename(self._ssk_key_name_hint + ".pem")
+ fsbl_config = ";".join(self._fsbl_config) if self._fsbl_config else None
+ auth_params = ";".join(self._auth_params) if self._auth_params else None
+
+ spl_elf_fname = tools.get_output_filename('u-boot-spl-pubkey.dtb.elf')
+
+ # We need to convert to node content (see above) into an ELF
+ # file in order to be processed by bootgen.
+ self._ToElf(bytearray(data), spl_elf_fname)
+
+ # Call Bootgen in order to sign the SPL
+ self.bootgen.sign('zynqmp', spl_elf_fname, pmufw_elf_fname,
+ psk_fname, ssk_fname, fsbl_config,
+ auth_params, self._keysrc_enc, bootbin_fname)
+
+ data = tools.read_file(bootbin_fname)
+ self.SetContents(data)
+
+ return data
+
+ # pylint: disable=C0116
+ def AddBintools(self, btools):
+ super().AddBintools(btools)
+ self.bootgen = self.AddBintool(btools, 'bootgen')
--
2.30.2
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