#
# Copyright OpenEmbedded Contributors
#
# SPDX-License-Identifier: MIT
#

# This class is used to generate metadata needed by external
# tools to check for vulnerabilities, for example CVEs.
#
# In order to use this class just inherit the class in the
# local.conf file and it will add the generate_vex task for
# every recipe. If an image is build it will generate a report
# in DEPLOY_DIR_IMAGE for all the packages used, it will also
# generate a file for all recipes used in the build.
#
# Variables use CVE_CHECK prefix to keep compatibility with
# the cve-check class
#
# Example:
#   bitbake -c generate_vex openssl
#   bitbake core-image-sato
#   bitbake -k -c generate_vex universe
#
# The product name that the CVE database uses defaults to BPN, but may need to
# be overriden per recipe (for example tiff.bb sets CVE_PRODUCT=libtiff).
CVE_PRODUCT ??= "${BPN}"
CVE_VERSION ??= "${PV}"

CVE_CHECK_SUMMARY_DIR ?= "${LOG_DIR}/cve"

CVE_CHECK_SUMMARY_FILE_NAME_JSON = "cve-summary.json"
CVE_CHECK_SUMMARY_INDEX_PATH = "${CVE_CHECK_SUMMARY_DIR}/cve-summary-index.txt"

CVE_CHECK_DIR ??= "${DEPLOY_DIR}/cve"
CVE_CHECK_RECIPE_FILE_JSON ?= "${CVE_CHECK_DIR}/${PN}_cve.json"
CVE_CHECK_MANIFEST_JSON ?= "${IMGDEPLOYDIR}/${IMAGE_NAME}.json"

# Skip CVE Check for packages (PN)
CVE_CHECK_SKIP_RECIPE ?= ""

# Replace NVD DB check status for a given CVE. Each of CVE has to be mentioned
# separately with optional detail and description for this status.
#
# CVE_STATUS[CVE-1234-0001] = "not-applicable-platform: Issue only applies on Windows"
# CVE_STATUS[CVE-1234-0002] = "fixed-version: Fixed externally"
#
# Settings the same status and reason for multiple CVEs is possible
# via CVE_STATUS_GROUPS variable.
#
# CVE_STATUS_GROUPS = "CVE_STATUS_WIN CVE_STATUS_PATCHED"
#
# CVE_STATUS_WIN = "CVE-1234-0001 CVE-1234-0003"
# CVE_STATUS_WIN[status] = "not-applicable-platform: Issue only applies on Windows"
# CVE_STATUS_PATCHED = "CVE-1234-0002 CVE-1234-0004"
# CVE_STATUS_PATCHED[status] = "fixed-version: Fixed externally"
#
# All possible CVE statuses could be found in cve-check-map.conf
# CVE_CHECK_STATUSMAP[not-applicable-platform] = "Ignored"
# CVE_CHECK_STATUSMAP[fixed-version] = "Patched"
#
# CVE_CHECK_IGNORE is deprecated and CVE_STATUS has to be used instead.
# Keep CVE_CHECK_IGNORE until other layers migrate to new variables
CVE_CHECK_IGNORE ?= ""

# Layers to be excluded
CVE_CHECK_LAYER_EXCLUDELIST ??= ""

# Layers to be included
CVE_CHECK_LAYER_INCLUDELIST ??= ""


# set to "alphabetical" for version using single alphabetical character as increment release
CVE_VERSION_SUFFIX ??= ""

python () {
    if bb.data.inherits_class("cve-check", d):
        raise bb.parse.SkipRecipe("Skipping recipe: found incompatible combination of cve-check and vex enabled at the same time.")

    # Fallback all CVEs from CVE_CHECK_IGNORE to CVE_STATUS
    cve_check_ignore = d.getVar("CVE_CHECK_IGNORE")
    if cve_check_ignore:
        bb.warn("CVE_CHECK_IGNORE is deprecated in favor of CVE_STATUS")
        for cve in (d.getVar("CVE_CHECK_IGNORE") or "").split():
            d.setVarFlag("CVE_STATUS", cve, "ignored")

    # Process CVE_STATUS_GROUPS to set multiple statuses and optional detail or description at once
    for cve_status_group in (d.getVar("CVE_STATUS_GROUPS") or "").split():
        cve_group = d.getVar(cve_status_group)
        if cve_group is not None:
            for cve in cve_group.split():
                d.setVarFlag("CVE_STATUS", cve, d.getVarFlag(cve_status_group, "status"))
        else:
            bb.warn("CVE_STATUS_GROUPS contains undefined variable %s" % cve_status_group)
}

def generate_json_report(d, out_path, link_path):
    if os.path.exists(d.getVar("CVE_CHECK_SUMMARY_INDEX_PATH")):
        import json
        from oe.cve_check import cve_check_merge_jsons, update_symlinks

        bb.note("Generating JSON CVE summary")
        index_file = d.getVar("CVE_CHECK_SUMMARY_INDEX_PATH")
        summary = {"version":"1", "package": []}
        with open(index_file) as f:
            filename = f.readline()
            while filename:
                with open(filename.rstrip()) as j:
                    data = json.load(j)
                    cve_check_merge_jsons(summary, data)
                filename = f.readline()

        summary["package"].sort(key=lambda d: d['name'])

        with open(out_path, "w") as f:
            json.dump(summary, f, indent=2)

        update_symlinks(out_path, link_path)

python vex_save_summary_handler () {
    import shutil
    import datetime
    from oe.cve_check import update_symlinks

    cvelogpath = d.getVar("CVE_CHECK_SUMMARY_DIR")

    bb.utils.mkdirhier(cvelogpath)
    timestamp = datetime.datetime.now().strftime('%Y%m%d%H%M%S')

    json_summary_link_name = os.path.join(cvelogpath, d.getVar("CVE_CHECK_SUMMARY_FILE_NAME_JSON"))
    json_summary_name = os.path.join(cvelogpath, "cve-summary-%s.json" % (timestamp))
    generate_json_report(d, json_summary_name, json_summary_link_name)
    bb.plain("Complete CVE JSON report summary created at: %s" % json_summary_link_name)
}

addhandler vex_save_summary_handler
vex_save_summary_handler[eventmask] = "bb.event.BuildCompleted"

python do_generate_vex () {
    """
    Generate metadata needed for vulnerability checking for
    the current recipe
    """
    from oe.cve_check import get_patched_cves

    try:
        patched_cves = get_patched_cves(d)
        cves_status = []
        products = d.getVar("CVE_PRODUCT").split()
        for product in products:
            if ":" in product:
                _, product = product.split(":", 1)
            cves_status.append([product, False])

    except FileNotFoundError:
        bb.fatal("Failure in searching patches")

    cve_write_data_json(d, patched_cves, cves_status)
}

addtask generate_vex before do_build

python vex_cleanup () {
    """
    Delete the file used to gather all the CVE information.
    """
    bb.utils.remove(e.data.getVar("CVE_CHECK_SUMMARY_INDEX_PATH"))
}

addhandler vex_cleanup
vex_cleanup[eventmask] = "bb.event.BuildCompleted"

python vex_write_rootfs_manifest () {
    """
    Create VEX/CVE manifest when building an image
    """

    import json
    from oe.rootfs import image_list_installed_packages
    from oe.cve_check import cve_check_merge_jsons, update_symlinks

    deploy_file_json = d.getVar("CVE_CHECK_RECIPE_FILE_JSON")
    if os.path.exists(deploy_file_json):
        bb.utils.remove(deploy_file_json)

    # Create a list of relevant recipies
    recipies = set()
    for pkg in list(image_list_installed_packages(d)):
        pkg_info = os.path.join(d.getVar('PKGDATA_DIR'),
                                'runtime-reverse', pkg)
        pkg_data = oe.packagedata.read_pkgdatafile(pkg_info)
        recipies.add(pkg_data["PN"])

    bb.note("Writing rootfs VEX manifest")
    deploy_dir = d.getVar("IMGDEPLOYDIR")
    link_name = d.getVar("IMAGE_LINK_NAME")

    json_data = {"version":"1", "package": []}
    text_data = ""

    save_pn = d.getVar("PN")

    for pkg in recipies:
        # To be able to use the CVE_CHECK_RECIPE_FILE_JSON variable we have to evaluate
        # it with the different PN names set each time.
        d.setVar("PN", pkg)

        pkgfilepath = d.getVar("CVE_CHECK_RECIPE_FILE_JSON")
        if os.path.exists(pkgfilepath):
            with open(pkgfilepath) as j:
                data = json.load(j)
                cve_check_merge_jsons(json_data, data)

    d.setVar("PN", save_pn)

    link_path = os.path.join(deploy_dir, "%s.json" % link_name)
    manifest_name = d.getVar("CVE_CHECK_MANIFEST_JSON")

    with open(manifest_name, "w") as f:
        json.dump(json_data, f, indent=2)

    update_symlinks(manifest_name, link_path)
    bb.plain("Image VEX JSON report stored in: %s" % manifest_name)
}

ROOTFS_POSTPROCESS_COMMAND:prepend = "vex_write_rootfs_manifest; "
do_rootfs[recrdeptask] += "do_generate_vex "
do_populate_sdk[recrdeptask] += "do_generate_vex "

def cve_write_data_json(d, cve_data, cve_status):
    """
    Prepare CVE data for the JSON format, then write it.
    Done for each recipe.
    """

    from oe.cve_check import get_cpe_ids
    import json

    output = {"version":"1", "package": []}
    nvd_link = "https://nvd.nist.gov/vuln/detail/"

    fdir_name  = d.getVar("FILE_DIRNAME")
    layer = fdir_name.split("/")[-3]

    include_layers = d.getVar("CVE_CHECK_LAYER_INCLUDELIST").split()
    exclude_layers = d.getVar("CVE_CHECK_LAYER_EXCLUDELIST").split()

    if exclude_layers and layer in exclude_layers:
        return

    if include_layers and layer not in include_layers:
        return

    product_data = []
    for s in cve_status:
        p = {"product": s[0], "cvesInRecord": "Yes"}
        if s[1] == False:
            p["cvesInRecord"] = "No"
        product_data.append(p)
    product_data = list({p['product']:p for p in product_data}.values())

    package_version = "%s%s" % (d.getVar("EXTENDPE"), d.getVar("PV"))
    cpes = get_cpe_ids(d.getVar("CVE_PRODUCT"), d.getVar("CVE_VERSION"))
    package_data = {
        "name" : d.getVar("PN"),
        "layer" : layer,
        "version" : package_version,
        "products": product_data,
        "cpes": cpes
    }

    cve_list = []

    for cve in sorted(cve_data):
        issue_link = "%s%s" % (nvd_link, cve)

        cve_item = {
            "id" : cve,
            "status" : cve_data[cve]["abbrev-status"],
            "link": issue_link,
        }
        if 'NVD-summary' in cve_data[cve]:
            cve_item["summary"] = cve_data[cve]["NVD-summary"]
            cve_item["scorev2"] = cve_data[cve]["NVD-scorev2"]
            cve_item["scorev3"] = cve_data[cve]["NVD-scorev3"]
            cve_item["vector"] = cve_data[cve]["NVD-vector"]
            cve_item["vectorString"] = cve_data[cve]["NVD-vectorString"]
        if 'status' in cve_data[cve]:
            cve_item["detail"] = cve_data[cve]["status"]
        if 'justification' in cve_data[cve]:
            cve_item["description"] = cve_data[cve]["justification"]
        if 'resource' in cve_data[cve]:
            cve_item["patch-file"] = cve_data[cve]["resource"]
        cve_list.append(cve_item)

    package_data["issue"] = cve_list
    output["package"].append(package_data)

    deploy_file = d.getVar("CVE_CHECK_RECIPE_FILE_JSON")

    write_string = json.dumps(output, indent=2)

    cvelogpath = d.getVar("CVE_CHECK_SUMMARY_DIR")
    index_path = d.getVar("CVE_CHECK_SUMMARY_INDEX_PATH")
    bb.utils.mkdirhier(cvelogpath)
    fragment_file = os.path.basename(deploy_file)
    fragment_path = os.path.join(cvelogpath, fragment_file)
    with open(fragment_path, "w") as f:
        f.write(write_string)
    with open(index_path, "a+") as f:
        f.write("%s\n" % fragment_path)