U-Boot

# SPDX-License-Identifier:	GPL-2.0+
# Copyright (c) 2013, Google Inc.

"""Sanity check of the FIT handling in U-Boot"""

import os
import struct

import pytest
import fit_util
import utils

# Define a base ITS which we can adjust using % and a dictionary
BASE_ITS = '''
/dts-v1/;

/ {
        description = "Chrome OS kernel image with one or more FDT blobs";
        #address-cells = <1>;

        images {
                kernel-1 {
                        data = /incbin/("%(kernel)s");
                        type = "kernel";
                        arch = "sandbox";
                        os = "linux";
                        compression = "%(compression)s";
                        load = <0x40000>;
                        entry = <0x8>;
                };
                kernel-2 {
                        data = /incbin/("%(loadables1)s");
                        type = "kernel";
                        arch = "sandbox";
                        os = "linux";
                        compression = "none";
                        %(loadables1_load)s
                        entry = <0x0>;
                };
                fdt-1 {
                        description = "snow";
                        data = /incbin/("%(fdt)s");
                        type = "flat_dt";
                        arch = "sandbox";
                        %(fdt_load)s
                        compression = "%(compression)s";
                        signature-1 {
                                algo = "sha1,rsa2048";
                                key-name-hint = "dev";
                        };
                };
                ramdisk-1 {
                        description = "snow";
                        data = /incbin/("%(ramdisk)s");
                        type = "ramdisk";
                        arch = "sandbox";
                        os = "linux";
                        %(ramdisk_load)s
                        compression = "%(compression)s";
                };
                ramdisk-2 {
                        description = "snow";
                        data = /incbin/("%(loadables2)s");
                        type = "ramdisk";
                        arch = "sandbox";
                        os = "linux";
                        %(loadables2_load)s
                        compression = "none";
                };
        };
        configurations {
                default = "conf-1";
                conf-1 {
                        %(kernel_config)s
                        %(fdt_config)s
                        %(ramdisk_config)s
                        %(loadables_config)s
                };
        };
};
'''

# Define a base FDT - currently we don't use anything in this
BASE_FDT = '''
/dts-v1/;

/ {
	#address-cells = <1>;
	#size-cells = <0>;

	model = "Sandbox Verified Boot Test";
	compatible = "sandbox";

	binman {
	};

	reset@0 {
		compatible = "sandbox,reset";
		reg = <0>;
	};
};
'''

# This is the U-Boot script that is run for each test. First load the FIT,
# then run the 'bootm' command, then save out memory from the places where
# we expect 'bootm' to write things. Then quit.
BASE_SCRIPT = '''
%(mem_clear)s
host load hostfs 0 %(fit_addr)x %(fit)s
fdt addr %(fit_addr)x
bootm %(start_subcmd)s %(fit_addr)x
bootm loados%(cmd_extra)s
host save hostfs 0 %(kernel_addr)x %(kernel_out)s %(kernel_size)x
host save hostfs 0 %(fdt_addr)x %(fdt_out)s %(fdt_size)x
host save hostfs 0 %(ramdisk_addr)x %(ramdisk_out)s %(ramdisk_size)x
host save hostfs 0 %(loadables1_addr)x %(loadables1_out)s %(loadables1_size)x
host save hostfs 0 %(loadables2_addr)x %(loadables2_out)s %(loadables2_size)x
'''

@pytest.mark.boardspec('sandbox')
@pytest.mark.buildconfigspec('fit_signature')
@pytest.mark.requiredtool('dtc')
class TestFitImage:
    """Test class for FIT image handling in U-Boot

    TODO: Almost everything:
      - hash algorithms - invalid hash/contents should be detected
      - signature algorithms - invalid sig/contents should be detected
      - compression
      - checking that errors are detected like:
            - image overwriting
            - missing images
            - invalid configurations
            - incorrect os/arch/type fields
            - empty data
            - images too large/small
            - invalid FDT (e.g. putting a random binary in instead)
      - default configuration selection
      - bootm command line parameters should have desired effect
      - run code coverage to make sure we are testing all the code
    """

    @pytest.fixture(autouse=True)
    def save_bootstage(self, ubman):
        """Save and restore bootstage around each test."""
        with utils.preserve_bootstage(ubman):
            yield

    def make_fname(self, ubman, leaf):
        """Make a temporary filename

        Args:
            ubman (ConsoleBase): U-Boot fixture
            leaf (str): Leaf name of file to create (within temporary directory)

        Return:
            str: Temporary filename
        """
        return os.path.join(ubman.config.build_dir, leaf)

    def filesize(self, fname):
        """Get the size of a file

        Args:
            fname (str): Filename to check

        Return:
            int: Size of file in bytes
        """
        return os.stat(fname).st_size

    def read_file(self, fname):
        """Read the contents of a file

        Args:
            fname (str): Filename to read

        Return:
            str: Contents of file
        """
        with open(fname, 'rb') as fd:
            return fd.read()

    def make_ramdisk(self, ubman, filename, text):
        """Make a sample ramdisk with test data

        Returns:
            str: Filename of ramdisk created
        """
        fname = self.make_fname(ubman, filename)
        data = ''
        for i in range(100):
            data += f'{text} {i} was seldom used in the middle ages\n'
        with open(fname, 'w', encoding='ascii') as fd:
            print(data, file=fd)
        return fname

    def make_compressed(self, ubman, filename):
        """Compress a file using gzip"""
        utils.run_and_log(ubman, ['gzip', '-f', '-k', filename])
        return filename + '.gz'

    def find_matching(self, text, match):
        """Find a match in a line of text, and return the unmatched line portion

        This is used to extract a part of a line from some text. The match string
        is used to locate the line - we use the first line that contains that
        match text.

        Once we find a match, we discard the match string itself from the line,
        and return what remains.

        TODO: If this function becomes more generally useful, we could change it
        to use regex and return groups.

        Args:
            text (list of str): Text to check, one for each command issued
            match (str): String to search for

        Return:
            str: unmatched portion of line

        Exceptions:
            ValueError: If match is not found

        >>> find_matching(['first line:10', 'second_line:20'], 'first line:')
        '10'
        >>> find_matching(['first line:10', 'second_line:20'], 'second line')
        Traceback (most recent call last):
          ...
        ValueError: Test aborted
        >>> find_matching('first line:10\', 'second_line:20'], 'second_line:')
        '20'
        >>> find_matching('first line:10\', 'second_line:20\nthird_line:30'],
                          'third_line:')
        '30'
        """
        # pylint: disable=W0612
        __tracebackhide__ = True
        for line in '\n'.join(text).splitlines():
            pos = line.find(match)
            if pos != -1:
                return line[:pos] + line[pos + len(match):]

        pytest.fail("Expected '%s' but not found in output")
        return '<no-match>'

    def check_equal(self, params, expected_fname, actual_fname, failure_msg):
        """Check that a file matches its expected contents

        This is always used on out-buffers whose size is decided by the test
        script anyway, which in some cases may be larger than what we're
        actually looking for. So it's safe to truncate it to the size of the
        expected data.

        Args:
            params (dict): Parameters dict from which to get the filenames
            expected_fname (str): Key for filename containing expected contents
            actual_fname (str): Key for filename containing actual contents
            failure_msg (str): Message to print on failure
        """
        expected_data = self.read_file(params[expected_fname])
        actual_data = self.read_file(params[actual_fname])
        if len(expected_data) < len(actual_data):
            actual_data = actual_data[:len(expected_data)]
        assert expected_data == actual_data, failure_msg

    def check_not_equal(self, params, expected_fname, actual_fname,
                        failure_msg):
        """Check that a file does not match its expected contents

        Args:
            params (dict): Parameters dict from which to get the filenames
            expected_fname (str): Key for filename containing expected contents
            actual_fname (str): Key for filename containing actual contents
            failure_msg (str): Message to print on failure
        """
        expected_data = self.read_file(params[expected_fname])
        actual_data = self.read_file(params[actual_fname])
        assert expected_data != actual_data, failure_msg

    @pytest.fixture()
    def fsetup(self, ubman):
        """A fixture to set up files and parameters for FIT tests

        Args:
            ubman (ConsoleBase): U-Boot fixture

        Yields:
            dict: Parameters needed by the test
        """
        mkimage = os.path.join(ubman.config.build_dir, 'tools/mkimage')

        # Set up invariant files
        fdt_data = fit_util.make_dtb(ubman, BASE_FDT, 'u-boot')
        kernel = fit_util.make_kernel(ubman, 'test-kernel.bin', 'kernel')
        ramdisk = self.make_ramdisk(ubman, 'test-ramdisk.bin', 'ramdisk')
        loadables1 = fit_util.make_kernel(ubman, 'test-loadables1.bin', 'lenrek')
        loadables2 = self.make_ramdisk(ubman, 'test-loadables2.bin', 'ksidmar')
        kernel_out = self.make_fname(ubman, 'kernel-out.bin')
        fdt = self.make_fname(ubman, 'u-boot.dtb')
        fdt_out = self.make_fname(ubman, 'fdt-out.dtb')
        ramdisk_out = self.make_fname(ubman, 'ramdisk-out.bin')
        loadables1_out = self.make_fname(ubman, 'loadables1-out.bin')
        loadables2_out = self.make_fname(ubman, 'loadables2-out.bin')

        # Set up basic parameters with default values
        params = {
            'fit_addr' : 0x1000,

            'kernel' : kernel,
            'kernel_out' : kernel_out,
            'kernel_addr' : 0x40000,
            'kernel_size' : self.filesize(kernel),
            'kernel_config' : 'kernel = "kernel-1";',

            'fdt' : fdt,
            'fdt_out' : fdt_out,
            'fdt_addr' : 0x80000,
            'fdt_size' : self.filesize(fdt_data),
            'fdt_load' : '',
            'fdt_config' : 'fdt = "fdt-1";',

            'ramdisk' : ramdisk,
            'ramdisk_out' : ramdisk_out,
            'ramdisk_addr' : 0xc0000,
            'ramdisk_size' : self.filesize(ramdisk),
            'ramdisk_load' : '',
            'ramdisk_config' : '',

            'loadables1' : loadables1,
            'loadables1_out' : loadables1_out,
            'loadables1_addr' : 0x100000,
            'loadables1_size' : self.filesize(loadables1),
            'loadables1_load' : '',

            'loadables2' : loadables2,
            'loadables2_out' : loadables2_out,
            'loadables2_addr' : 0x140000,
            'loadables2_size' : self.filesize(loadables2),
            'loadables2_load' : '',

            'loadables_config' : '',
            'compression' : 'none',

            'mem_clear': 'mw 0 0 180000',
            'start_subcmd': 'start',
            'cmd_extra': '',
            'fit_basename': 'test.fit',
        }

        # Yield all necessary components to the tests
        params.update({
            'mkimage': mkimage,
            'fdt_data': fdt_data,
        })
        yield params

    def prepare(self, ubman, fsetup, **kwargs):
        """Build a FIT with given params

        Uses the base parameters to create a FIT and a script to test it,

        For the use of eval here to evaluate f-strings, see:
            https://stackoverflow.com/questions/42497625/how-to-postpone-defer-the-evaluation-of-f-strings

        Args:
            ubman (ConsoleBase): U-Boot fixture
            fsetup (dict): Information about the test setup
            kwargs (dict): Changes to make to the default params
                key (str): parameter to change
                val (str): f-string to evaluate to get the parameter value

        Return:
            tuple:
                list of str: Commands to run for the test
                dict: Parameters used by the test
                str: Filename of the FIT that was created
        """
        params = fsetup.copy()
        for name, template in kwargs.items():
            # pylint: disable=W0123
            params[name] = eval(f'f"""{template}"""')

        # Make a basic FIT and a script to load it
        fit = fit_util.make_fit(ubman, params['mkimage'], BASE_ITS, params,
                                basename=params['fit_basename'])
        params['fit'] = fit
        cmds = BASE_SCRIPT % params

        return cmds.splitlines(), params, fit

    def test_fit_kernel_load(self, ubman, fsetup):
        """Test loading a FIT image with only a kernel"""
        cmds, params, fit = self.prepare(ubman, fsetup)

        # Run and verify
        output = ubman.run_command_list(cmds)
        self.check_equal(params, 'kernel', 'kernel_out', 'Kernel not loaded')
        self.check_not_equal(params, 'fdt_data', 'fdt_out',
                             'FDT loaded but should be ignored')
        self.check_not_equal(params, 'ramdisk','ramdisk_out',
                             'Ramdisk loaded but should not be')

        # Find out the offset in the FIT where U-Boot has found the FDT
        line = self.find_matching(output, 'Booting using the fdt blob at ')
        fit_offset = int(line, 16) - params['fit_addr']
        fdt_magic = struct.pack('>L', 0xd00dfeed)
        data = self.read_file(fit)

        # Now find where it actually is in the FIT (skip the first word)
        real_fit_offset = data.find(fdt_magic, 4)
        assert fit_offset == real_fit_offset, (
            f'U-Boot loaded FDT from offset {fit_offset:#x}, '
             'FDT is actually at {real_fit_offset:#x}')

        # Check bootargs string substitution
        output = ubman.run_command_list([
            'env set bootargs \\"\'my_boot_var=${foo}\'\\"',
            'env set foo bar',
            'bootm prep',
            'env print bootargs'])
        assert 'bootargs="my_boot_var=bar"' in output, \
                "Bootargs strings not substituted"

    def test_fit_kernel_fdt_load(self, ubman, fsetup):
        """Test loading a FIT image with a kernel and FDT"""
        cmds, params, _ = self.prepare(
            ubman, fsetup, fdt_load="load = <{params['fdt_addr']:#x}>;")

        # Run and verify
        ubman.run_command_list(cmds)
        self.check_equal(params, 'kernel', 'kernel_out', 'Kernel not loaded')
        self.check_equal(params, 'fdt_data', 'fdt_out', 'FDT not loaded')
        self.check_not_equal(params, 'ramdisk', 'ramdisk_out',
                             'Ramdisk loaded but should not be')

    def test_fit_kernel_fdt_ramdisk_load(self, ubman, fsetup):
        """Test loading a FIT image with kernel, FDT, and ramdisk"""
        cmds, params, _ = self.prepare(
            ubman, fsetup,
            fdt_load="load = <{params['fdt_addr']:#x}>;",
            ramdisk_config='ramdisk = "ramdisk-1";',
            ramdisk_load="load = <{params['ramdisk_addr']:#x}>;")

        # Run and verify
        ubman.run_command_list(cmds)
        self.check_equal(params, 'ramdisk', 'ramdisk_out', 'Ramdisk not loaded')

    def test_fit_loadables_load(self, ubman, fsetup):
        """Test a configuration with 'loadables' properties"""
        # Configure for FDT, ramdisk, and loadables
        cmds, params, _ = self.prepare(
            ubman, fsetup,
            fdt_load="load = <{params['fdt_addr']:#x}>;",
            ramdisk_config='ramdisk = "ramdisk-1";',
            ramdisk_load="load = <{params['ramdisk_addr']:#x}>;",
            loadables_config='loadables="kernel-2", "ramdisk-2";',
            loadables1_load="load = <{params['loadables1_addr']:#x}>;",
            loadables2_load="load = <{params['loadables2_addr']:#x}>;")

        # Run and verify
        ubman.run_command_list(cmds)
        self.check_equal(params, 'loadables1', 'loadables1_out',
                         'Loadables1 (kernel) not loaded')
        self.check_equal(params, 'loadables2', 'loadables2_out',
                         'Loadables2 (ramdisk) not loaded')

    def test_fit_compressed_images_load(self, ubman, fsetup):
        """Test loading compressed kernel, FDT, and ramdisk images"""
        # Configure for FDT and ramdisk load
        cmds, params, _ = self.prepare(
            ubman, fsetup,
            fdt_load="load = <{params['fdt_addr']:#x}>;",
            ramdisk_config='ramdisk = "ramdisk-1";',
            ramdisk_load="load = <{params['ramdisk_addr']:#x}>;",

            # Configure for compression
            compression='gzip',
            kernel=self.make_compressed(ubman, fsetup['kernel']),
            fdt=self.make_compressed(ubman, fsetup['fdt']),
            ramdisk=self.make_compressed(ubman, fsetup['ramdisk']))

        # Run and verify
        ubman.run_command_list(cmds)
        self.check_equal(fsetup, 'kernel', 'kernel_out', 'Kernel not loaded')
        self.check_equal(fsetup, 'fdt_data', 'fdt_out', 'FDT not loaded')
        self.check_not_equal(fsetup, 'ramdisk', 'ramdisk_out',
                             'Ramdisk got decompressed?')
        self.check_equal(params, 'ramdisk', 'ramdisk_out', 'Ramdisk not loaded')

    def test_fit_no_kernel_load(self, ubman, fsetup):
        """Test that 'bootm' fails when no kernel is specified"""
        # Configure for FDT load but no kernel or ramdisk
        cmds = self.prepare(
            ubman, fsetup,
            fdt_load="load = <{params['fdt_addr']:#x}>;",
            kernel_config='',
            ramdisk_config='',
            ramdisk_load='')[0]

        # Run and verify failure
        output = ubman.run_command_list(cmds)
        assert "can't get kernel image!" in '\n'.join(output)

    def test_fit_no_kernel_load_only(self, ubman, fsetup):
        """Test that 'bootm' handles a load-only FIT"""
        cmds = self.prepare(
            ubman, fsetup,
            kernel_config='load-only;',
            fdt_load="load = <{params['fdt_addr']:#x}>;",
            ramdisk_config='ramdisk = "ramdisk-1";',
            ramdisk_load="load = <{params['ramdisk_addr']:#x}>;",
            loadables_config='loadables = "kernel-2", "ramdisk-2";',
            loadables1_load="load = <{params['loadables1_addr']:#x}>;",
            loadables2_load="load = <{params['loadables2_addr']:#x}>;")[0]

        lines = ubman.run_command_list(cmds)
        output = '\n'.join(lines)
        assert "can't get kernel image!" not in output
        assert "Detected load-only image: skipping 'kernel'" in output
        self.check_equal(fsetup, 'fdt_data', 'fdt_out', 'FDT not loaded')
        self.check_equal(fsetup, 'ramdisk', 'ramdisk_out', 'Ramdisk not loaded')
        self.check_equal(fsetup, 'loadables1', 'loadables1_out',
                         'Loadables1 (kernel) not loaded')
        self.check_equal(fsetup, 'loadables2', 'loadables2_out',
                         'Loadables2 (ramdisk) not loaded')

    def test_fit_no_kernel_second(self, ubman, fsetup):
        """Test that 'bootm' handles a load-only FIT and a second FIT"""
        cmds = self.prepare(
            ubman, fsetup,
            kernel_config='load-only;',
            # Just load a devicetree for the first FIT
            ramdisk_config='',
            ramdisk_load='',
            fdt_load="load = <{params['fdt_addr']:#x}>;")[0]

        lines = ubman.run_command_list(cmds)
        output = '\n'.join(lines)
        assert "can't get kernel image!" not in output
        assert "Detected load-only image: skipping 'kernel'" in output
        self.check_equal(fsetup, 'fdt_data', 'fdt_out', 'FDT not loaded')

        # Now load a second FIT which has a kernel and ramdisk
        cmds = self.prepare(
            ubman, fsetup,
            fdt_config= '',
            fdt_load='',
            ramdisk_config='ramdisk = "ramdisk-1";',
            ramdisk_load="load = <{params['ramdisk_addr']:#x}>;",
            # fit=fit
            mem_clear='',

            # Run the prep stage so we can check that the FDT-fixups are done
            cmd_extra='\nbootm cmdline\nbootm prep',
            start_subcmd='restart',
            fit_basename='second.fit')[0]

        # Run and verify
        lines = ubman.run_command_list(cmds)
        output = '\n'.join(lines)
        assert "can't get kernel image!" not in output
        assert "Detected load-only image: skipping 'kernel'" not in output
        self.check_equal(fsetup, 'kernel', 'kernel_out', 'Kernel not loaded')
        self.check_equal(fsetup, 'ramdisk', 'ramdisk_out', 'Ramdisk not loaded')

        # Check that the devicetree is still there
        self.check_equal(fsetup, 'fdt_data', 'fdt_out', 'FDT not loaded')