WebAuthnAbstractEvent::cborDecode() - Code Metrics - Inspection of "Attempt to fix phpstan-issue" - simplesamlphp/simplesamlphp-module-webauthn - Measure and Improve Code Quality continuously with Scrutinizer

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by Tim

created 2024-08-13 10:08 UTC

WebAuthnAbstractEvent::cborDecode() A

↳ Parent: Project

Complexity

Conditions	2
Paths	2

Size

Total Lines	32
Code Lines	26

Duplication

Lines	0
Ratio	0 %

Importance

Changes	3
Bugs	0	Features	0

Metric	Value
cc	2
eloc	26
c	3
b	0
f	0
nc	2
nop	1
dl	0
loc	32
rs	9.504

<?php

declare(strict_types=1);

namespace SimpleSAML\Module\webauthn\WebAuthn;

use CBOR\Decoder;
use CBOR\Normalized;
use CBOR\OtherObject;
use CBOR\StringStream;
use CBOR\Tag;
use SimpleSAML\Utils\HTTP as HTTPHelper;

/**
 * FIDO2/WebAuthn Authentication Processing filter
 *
 * Filter for registering or authenticating with a FIDO2/WebAuthn token after
 * having authenticated with the primary authsource.
 *
 * @author Stefan Winter <[email protected]>
 * @package SimpleSAMLphp
 */
abstract class WebAuthnAbstractEvent
{
    public const PRESENCE_LEVEL_PRESENT = 1;
    public const PRESENCE_LEVEL_VERIFIED = 4;
    public const PRESENCE_LEVEL_NONE = 0;

    /**
     * The SHA256 hash of the clientDataJSON
     *
     * @var string
     */
    protected string $clientDataHash;

    /**
     * the authenticator's signature counter
     *
     * @var int
     */
    protected int $counter;

    /**
     * the authenticator's signature algorithm
     *
     * @var int
     */
    protected int $algo;

    /**
     * UV or UP bit?
     */
    protected int $presenceLevel;

    /**
     * A string buffer to hold debug information in case we need it.
     *
     * @var string
     */
    protected string $debugBuffer = '';

    /**
     * A string buffer to hold raw validation data in case we want to look at it.
     *
     * @var string
     */
    protected string $validateBuffer = '';

    /**
     * the type of event requested. This is to be set in child class constructors
     * before calling the parent's.
     *
     * @var string
     */
    protected string $eventType;

    /**
     * The rpIdHash, available once validated during constructor of base class
     */
    protected string $rpIdHash;

    /**
     * the credential ID for this event (either the one that gets registered, or
     * the one that gets used to authenticate)
     *
     * To be set by the constructors of the child classes.
     *
     * @var string
     */
    protected string $credentialId;

    /**
     * the credential binary data for this event (either the one that gets
     * registered, or the one that gets used to authenticate)
     *
     * To be set by the constructors of the child classes.
     *
     * @var string
     */
    protected string $credential;


    /**
     * Initialize the event object.
     *
     * Validates and parses the configuration.
     *
     * @param string $pubkeyCredType  PublicKeyCredential.type
     * @param string $scope           the scope of the event
     * @param string $challenge       the challenge which was used to trigger this event
     * @param string $authData        the authData / authenticatorData structure which is present in all types of events
     * @param string $clientDataJSON  the client data JSON string which is present in all types of events
     * @param bool   $debugMode       shall we collect and output some extensive debugging information along the way?
     */
    public function __construct(
        string $pubkeyCredType,
        protected string $scope,
        protected string $challenge,
        string $authData,
        string $clientDataJSON,
        protected bool $debugMode = false,
    ) {
        $this->presenceLevel = self::PRESENCE_LEVEL_NONE;
        $this->debugBuffer .= "PublicKeyCredential.type: $pubkeyCredType<br/>";
        /**
         * This is not a required validation as per spec. Still odd that Firefox returns
         * "undefined" even though its own API spec says it will send "public-key".
         */
        switch ($pubkeyCredType) {
            case "public-key":
                $this->pass("Key Type OK");
                break;
            case "undefined":
                $this->warn("Key Type 'undefined' - Firefox or Yubikey issue?");
                break;
            default:
                $this->fail("Unknown Key Type: " . $_POST['type']);
                break;
        }

        /**
         * eventType is already set by child constructor, otherwise the function
         * will fail because of the missing type)
         */
        $this->clientDataHash = $this->verifyClientDataJSON($clientDataJSON);
        $this->counter = $this->validateAuthData($authData);
    }

    /**
     * @return int
     */
    public function getCounter(): int
    {
        return $this->counter;
    }

    /**
     * @return string
     */
    public function getCredential(): string
    {
        return $this->credential;
    }

   /**
     * @return int
     */
    public function getAlgo(): int
    {
        return $this->algo;
    }

    /**
     * @return int
     */
    public function getPresenceLevel(): int
    {
        return $this->presenceLevel;
    }

    /**
     * @return string
     */
    public function getCredentialId(): string
    {
        return $this->credentialId;
    }

    /**
     * @return string
     */
    public function getDebugBuffer(): string
    {
        return $this->debugBuffer;
    }

    /**
     * @return string
     */
    public function getValidateBuffer(): string
    {
        return $this->validateBuffer;
    }

    /**
     * The base64url decode function differs slightly from base64. Thanks.
     *
     * taken from https://gist.github.com/nathggns/6652997
     *
     * @param string $data the base64url-encoded source string
     * @return string the decoded string
     */
    public static function base64urlDecode(string $data): string
    {
        return base64_decode(strtr($data, '-_', '+/'));
    }

    /**
     * this function validates the content of clientDataJSON.
     * I.e. it performs
     *   - for a REGistration session
     *     - the validation steps 2 through 8 of the validation
     *     - the parts of step 14 that relate to clientDataJSON
     *   - for a AUTHentication session
     *     - the validation steps 6 through 11 of the validation
     *     - the parts of step 15 that relate to clientDataJSON
     *
     * @param string $clientDataJSON the incoming data
     *
     * @return string
     */
    private function verifyClientDataJSON(string $clientDataJSON): string
    {
        /**
         * §7.1 STEP 2 + 3 : convert to JSON and dissect JSON into PHP associative array
         * §7.2 STEP 6 + 7 : convert to JSON and dissect JSON into PHP associative array
         */
        $this->debugBuffer .= "ClientDataJSON hash: " . hash("sha256", $clientDataJSON) . "<br/>";
        $clientData = json_decode($clientDataJSON, true);
        $this->debugBuffer .= "<pre>" . /** @scrutinizer ignore-type */ print_r($clientData, true) . "</pre>";
        switch ($this->eventType) {
            case "REG":
                if ($clientData['type'] == "webauthn.create") {
                    /**
                     * §7.1 STEP 4 wheck for webauthn.create
                     */
                    $this->pass("Registration requested; type has expected value");
                } else {
                    $this->fail("REG requested, but did not receive webauthn.create.");
                }
                break;
            case "AUTH":
                if ($clientData['type'] == "webauthn.get") {
                    /**
                     * §7.2 STEP 8: check for webauthn.get
                     */
                    $this->pass("Authentication requested; type has expected value");
                } else {
                    $this->fail("AUTH requested, but did not receive webauthn.get.");
                }
                break;
            default:
                $this->fail("Unexpected operation " . $this->eventType);
                break;
        }

        /**
         * §7.1 STEP 5 : check if incoming challenge matches issued challenge
         * §7.2 STEP 9 : check if incoming challenge matches issued challenge
         */
        if ($this->challenge == bin2hex(WebAuthnAbstractEvent::base64urlDecode($clientData['challenge']))) {
            $this->pass("Challenge matches");
        } else {
            $this->fail("Challenge does not match");
        }

        /**
         * §7.1 STEP 6 : check if incoming origin matches our hostname (taken from IdP metadata prefix)
         * §7.2 STEP 10: check if incoming origin matches our hostname (taken from IdP metadata prefix)
         */
        $httpHeler = new HTTPHelper();
        $slash = strpos($httpHeler->getBaseURL(), '/', 8);
        $expectedOrigin = ($slash !== false) ? substr($httpHeler->getBaseURL(), 0, $slash) : $slash;
        if ($clientData['origin'] === $expectedOrigin) {
            $this->pass("Origin matches");
        } else {
            $this->fail("Origin does not match: " . $expectedOrigin);
        }

        /**
         * §7.1 STEP 7 : optional tokenBinding check. The Yubikey does not make use of that option.
         * §7.2 STEP 11: optional tokenBinding check. The Yubikey does not make use of that option.
         */
        if (!isset($clientData['tokenBinding'])) {
            $this->pass("No optional token binding data to validate.");
        } else {
            $this->warn("Validation of the present token binding data not implemented, continuing without!");
        }

        /**
         * §7.1 STEP 8 : SHA-256 hashing the clientData
         * §7.2 STEP 16: SHA-256 hashing the clientData
         */
        return hash("sha256", $clientDataJSON, true);
    }

    /**
     * This function performs the required checks on the authData (REG) or authenticatorData (AUTH) structure
     *
     * I.e. it performs
     *   - for a REGistration session
     *     - the validation steps 10-12 of the validation
     *     - the parts of step 14 that relate to authData
     *   - for a AUTHentication session
     *     - the validation steps 12-14 of the validation
     *     - the parts of step 15 that relate to authData
     *
     * @param string $authData           the authData / authenticatorData binary blob
     *
     * @return int the current counter value of the authenticator
     */
    private function validateAuthData(string $authData): int
    {
        $this->debugBuffer .= "AuthData: <pre>";
        $this->debugBuffer .= print_r($authData, true);
        $this->debugBuffer .= "</pre>";

        /**
         * §7.1 STEP 10: compare incoming RpId hash with expected value
         * §7.2 STEP 12: compare incoming RpId hash with expected value
         */
        if (bin2hex(substr($authData, 0, 32)) == hash("sha256", $this->scope)) {
            $this->pass("Relying Party hash correct.");
            $this->rpIdHash = hash("sha256", $this->scope);
        } else {
            $this->fail("Mismatching Relying Party hash.");
        }
        $bitfield = substr($authData, 32, 1);

        /**
         * §7.1 STEP 14 (authData part): no extensions were requested, so none are allowed to be present
         * §7.2 STEP 15 (authData part): no extensions were requested, so none are allowed to be present
         */
        if ((128 & ord($bitfield)) > 0) {
            // so we get Extensions. We typically ignore all, but the
            // "credProtect" one may be interesting in the future.
            $this->pass("ED: Extension Data included. Interesting bits may be extracted later.");
        } else {
            $this->pass("ED: Extension Data not present.");
        }

        switch ($this->eventType) {
            case "REG":
                if ((64 & ord($bitfield)) > 0) {
                    $this->pass("AT: Attested Credential Data Included.");
                } else {
                    $this->fail("AT: not present, but required during registration.");
                }
                // REG events parse their registration-related Extensions, if
                // any, in the WebAuthnRegistrationEvent subclass
                break;
            case "AUTH":
                if ((64 & ord($bitfield)) > 0) {
                    $this->fail("AT: Attested Credential Data Included.");
                } else {
                    $this->pass("AT: not present, like it should be during an authentication.");
                }
                // AUTH events can also have extensions. Extensions, if any,
                // would follow after the counter. We allow them to be present
                // but don't currently do anything with them, so let's
                // just make a useless extraction here as a reminder.
                $extensionBytes = substr($authData, 37);
                if (strlen($extensionBytes) > 0) {
                    // assign into variable and process if needed
                    $this->cborDecode($extensionBytes);
                }
                break;
            default:
                $this->fail("unknown type of operation!");
                break;
        }

        /**
         * §7.1 STEP 11 + 12 : check user presence (this implementation does not insist on verification currently)
         * §7.2 STEP 13 + 14 : check user presence (this implementation does not insist on verification currently)
         */
        if ((4 & ord($bitfield)) > 0) {
            $this->presenceLevel = self::PRESENCE_LEVEL_VERIFIED;
            $this->pass("UV indicated: User is personally identified by the token.");
        } elseif ((1 & ord($bitfield)) > 0) {
            $this->presenceLevel = self::PRESENCE_LEVEL_PRESENT;
            $this->pass("UP indicated: someone is present and triggered the token.");
        } else {
            $this->fail("Neither UV nor UP asserted: user is possibly not present at computer.");
        }
        $counterBin = substr($authData, 33, 4);

        $counterDec = intval(bin2hex($counterBin), 16);
        $this->debugBuffer .= "Signature Counter: $counterDec<br/>";
        return $counterDec;
    }

    /**
     * this function takes a binary CBOR blob and decodes it into an associative PHP array.
     *
     * @param string $rawData the binary CBOR blob
     * @return array the decoded CBOR data
     */
    protected function cborDecode(string $rawData): array
    {
        $otherObjectManager = new OtherObject\OtherObjectManager();
        $otherObjectManager->add(OtherObject\SimpleObject::class);
        $otherObjectManager->add(OtherObject\FalseObject::class);
        $otherObjectManager->add(OtherObject\TrueObject::class);
        $otherObjectManager->add(OtherObject\NullObject::class);
        $otherObjectManager->add(OtherObject\UndefinedObject::class);
        $otherObjectManager->add(OtherObject\HalfPrecisionFloatObject::class);
        $otherObjectManager->add(OtherObject\SinglePrecisionFloatObject::class);
        $otherObjectManager->add(OtherObject\DoublePrecisionFloatObject::class);

        $tagManager = new Tag\TagManager();
        $tagManager->add(Tag\DatetimeTag::class);
        $tagManager->add(Tag\TimestampTag::class);
        $tagManager->add(Tag\UnsignedBigIntegerTag::class);
        $tagManager->add(Tag\NegativeBigIntegerTag::class);
        $tagManager->add(Tag\DecimalFractionTag::class);
        $tagManager->add(Tag\BigFloatTag::class);
        $tagManager->add(Tag\Base64UrlEncodingTag::class);
        $tagManager->add(Tag\Base64EncodingTag::class);
        $tagManager->add(Tag\Base16EncodingTag::class);

        $decoder = new Decoder($tagManager, $otherObjectManager);
        $stream = new StringStream($rawData);

        $finalData = $decoder->decode($stream);
        if ($finalData implements Normalized) {

            $finalData = $finalData->normalize();
        }

        if ($finalData === null) {
            $this->fail("CBOR data decoding failed.");
        }
        return $finalData;
    }

    /**
     * @param string $text
     * @return void
     */
    protected function warn(string $text): void
    {
        $this->validateBuffer .= "<span style='background-color:yellow;'>WARN: $text</span><br/>";
    }

    /**
     * @param string $text
     * @throws \Exception
     * @return void
     */
    protected function fail(string $text): void
    {
        $this->validateBuffer .= "<span style='background-color:red;'>FAIL: $text</span><br/>";
        if ($this->debugMode === true) {
            echo $this->debugBuffer;
            echo $this->validateBuffer;
        }
        throw new \Exception($text);
    }

    /**
     * @param string $text
     * @return void
     */
    protected function pass(string $text): void
    {
        $this->validateBuffer .= "<span style='background-color:green; color:white;'>PASS: $text</span><br/>";
    }

    /**
     * @param string $text
     * @return void
     */
    protected function ignore(string $text): void
    {
        $this->validateBuffer .= "<span style='background-color:blue; color:white;'>IGNORE: $text</span><br/>";
    }
}


1			<?php
2
3			declare(strict_types=1);
4
5			namespace SimpleSAML\Module\webauthn\WebAuthn;
6
7			use CBOR\Decoder;
8			use CBOR\Normalized;
9			use CBOR\OtherObject;
10			use CBOR\StringStream;
11			use CBOR\Tag;
12			use SimpleSAML\Utils\HTTP as HTTPHelper;
13
14			/**
15			* FIDO2/WebAuthn Authentication Processing filter
16			*
17			* Filter for registering or authenticating with a FIDO2/WebAuthn token after
18			* having authenticated with the primary authsource.
19			*
20			* @author Stefan Winter <[email protected]>
21			* @package SimpleSAMLphp
22			*/
23			abstract class WebAuthnAbstractEvent
24			{
25			public const PRESENCE_LEVEL_PRESENT = 1;
26			public const PRESENCE_LEVEL_VERIFIED = 4;
27			public const PRESENCE_LEVEL_NONE = 0;
28
29			/**
30			* The SHA256 hash of the clientDataJSON
31			*
32			* @var string
33			*/
34			protected string $clientDataHash;
35
36			/**
37			* the authenticator's signature counter
38			*
39			* @var int
40			*/
41			protected int $counter;
42
43			/**
44			* the authenticator's signature algorithm
45			*
46			* @var int
47			*/
48			protected int $algo;
49
50			/**
51			* UV or UP bit?
52			*/
53			protected int $presenceLevel;
54
55			/**
56			* A string buffer to hold debug information in case we need it.
57			*
58			* @var string
59			*/
60			protected string $debugBuffer = '';
61
62			/**
63			* A string buffer to hold raw validation data in case we want to look at it.
64			*
65			* @var string
66			*/
67			protected string $validateBuffer = '';
68
69			/**
70			* the type of event requested. This is to be set in child class constructors
71			* before calling the parent's.
72			*
73			* @var string
74			*/
75			protected string $eventType;
76
77			/**
78			* The rpIdHash, available once validated during constructor of base class
79			*/
80			protected string $rpIdHash;
81
82			/**
83			* the credential ID for this event (either the one that gets registered, or
84			* the one that gets used to authenticate)
85			*
86			* To be set by the constructors of the child classes.
87			*
88			* @var string
89			*/
90			protected string $credentialId;
91
92			/**
93			* the credential binary data for this event (either the one that gets
94			* registered, or the one that gets used to authenticate)
95			*
96			* To be set by the constructors of the child classes.
97			*
98			* @var string
99			*/
100			protected string $credential;
101
102
103			/**
104			* Initialize the event object.
105			*
106			* Validates and parses the configuration.
107			*
108			* @param string $pubkeyCredType PublicKeyCredential.type
109			* @param string $scope the scope of the event
110			* @param string $challenge the challenge which was used to trigger this event
111			* @param string $authData the authData / authenticatorData structure which is present in all types of events
112			* @param string $clientDataJSON the client data JSON string which is present in all types of events
113			* @param bool $debugMode shall we collect and output some extensive debugging information along the way?
114			*/
115			public function __construct(
116			string $pubkeyCredType,
117			protected string $scope,
118			protected string $challenge,
119			string $authData,
120			string $clientDataJSON,
121			protected bool $debugMode = false,
122			) {
123			$this->presenceLevel = self::PRESENCE_LEVEL_NONE;
124			$this->debugBuffer .= "PublicKeyCredential.type: $pubkeyCredType<br/>";
125			/**
126			* This is not a required validation as per spec. Still odd that Firefox returns
127			* "undefined" even though its own API spec says it will send "public-key".
128			*/
129			switch ($pubkeyCredType) {
130			case "public-key":
131			$this->pass("Key Type OK");
132			break;
133			case "undefined":
134			$this->warn("Key Type 'undefined' - Firefox or Yubikey issue?");
135			break;
136			default:
137			$this->fail("Unknown Key Type: " . $_POST['type']);
138			break;
139			}
140
141			/**
142			* eventType is already set by child constructor, otherwise the function
143			* will fail because of the missing type)
144			*/
145			$this->clientDataHash = $this->verifyClientDataJSON($clientDataJSON);
146			$this->counter = $this->validateAuthData($authData);
147			}
148
149			/**
150			* @return int
151			*/
152			public function getCounter(): int
153			{
154			return $this->counter;
155			}
156
157			/**
158			* @return string
159			*/
160			public function getCredential(): string
161			{
162			return $this->credential;
163			}
164
165			/**
166			* @return int
167			*/
168			public function getAlgo(): int
169			{
170			return $this->algo;
171			}
172
173			/**
174			* @return int
175			*/
176			public function getPresenceLevel(): int
177			{
178			return $this->presenceLevel;
179			}
180
181			/**
182			* @return string
183			*/
184			public function getCredentialId(): string
185			{
186			return $this->credentialId;
187			}
188
189			/**
190			* @return string
191			*/
192			public function getDebugBuffer(): string
193			{
194			return $this->debugBuffer;
195			}
196
197			/**
198			* @return string
199			*/
200			public function getValidateBuffer(): string
201			{
202			return $this->validateBuffer;
203			}
204
205			/**
206			* The base64url decode function differs slightly from base64. Thanks.
207			*
208			* taken from https://gist.github.com/nathggns/6652997
209			*
210			* @param string $data the base64url-encoded source string
211			* @return string the decoded string
212			*/
213			public static function base64urlDecode(string $data): string
214			{
215			return base64_decode(strtr($data, '-_', '+/'));
216			}
217
218			/**
219			* this function validates the content of clientDataJSON.
220			* I.e. it performs
221			* - for a REGistration session
222			* - the validation steps 2 through 8 of the validation
223			* - the parts of step 14 that relate to clientDataJSON
224			* - for a AUTHentication session
225			* - the validation steps 6 through 11 of the validation
226			* - the parts of step 15 that relate to clientDataJSON
227			*
228			* @param string $clientDataJSON the incoming data
229			*
230			* @return string
231			*/
232			private function verifyClientDataJSON(string $clientDataJSON): string
233			{
234			/**
235			* §7.1 STEP 2 + 3 : convert to JSON and dissect JSON into PHP associative array
236			* §7.2 STEP 6 + 7 : convert to JSON and dissect JSON into PHP associative array
237			*/
238			$this->debugBuffer .= "ClientDataJSON hash: " . hash("sha256", $clientDataJSON) . "<br/>";
239			$clientData = json_decode($clientDataJSON, true);
240			$this->debugBuffer .= "<pre>" . /** @scrutinizer ignore-type */ print_r($clientData, true) . "</pre>";
241			switch ($this->eventType) {
242			case "REG":
243			if ($clientData['type'] == "webauthn.create") {
244			/**
245			* §7.1 STEP 4 wheck for webauthn.create
246			*/
247			$this->pass("Registration requested; type has expected value");
248			} else {
249			$this->fail("REG requested, but did not receive webauthn.create.");
250			}
251			break;
252			case "AUTH":
253			if ($clientData['type'] == "webauthn.get") {
254			/**
255			* §7.2 STEP 8: check for webauthn.get
256			*/
257			$this->pass("Authentication requested; type has expected value");
258			} else {
259			$this->fail("AUTH requested, but did not receive webauthn.get.");
260			}
261			break;
262			default:
263			$this->fail("Unexpected operation " . $this->eventType);
264			break;
265			}
266
267			/**
268			* §7.1 STEP 5 : check if incoming challenge matches issued challenge
269			* §7.2 STEP 9 : check if incoming challenge matches issued challenge
270			*/
271			if ($this->challenge == bin2hex(WebAuthnAbstractEvent::base64urlDecode($clientData['challenge']))) {
272			$this->pass("Challenge matches");
273			} else {
274			$this->fail("Challenge does not match");
275			}
276
277			/**
278			* §7.1 STEP 6 : check if incoming origin matches our hostname (taken from IdP metadata prefix)
279			* §7.2 STEP 10: check if incoming origin matches our hostname (taken from IdP metadata prefix)
280			*/
281			$httpHeler = new HTTPHelper();
282			$slash = strpos($httpHeler->getBaseURL(), '/', 8);
283			$expectedOrigin = ($slash !== false) ? substr($httpHeler->getBaseURL(), 0, $slash) : $slash;
284			if ($clientData['origin'] === $expectedOrigin) {
285			$this->pass("Origin matches");
286			} else {
287			$this->fail("Origin does not match: " . $expectedOrigin);
288			}
289
290			/**
291			* §7.1 STEP 7 : optional tokenBinding check. The Yubikey does not make use of that option.
292			* §7.2 STEP 11: optional tokenBinding check. The Yubikey does not make use of that option.
293			*/
294			if (!isset($clientData['tokenBinding'])) {
295			$this->pass("No optional token binding data to validate.");
296			} else {
297			$this->warn("Validation of the present token binding data not implemented, continuing without!");
298			}
299
300			/**
301			* §7.1 STEP 8 : SHA-256 hashing the clientData
302			* §7.2 STEP 16: SHA-256 hashing the clientData
303			*/
304			return hash("sha256", $clientDataJSON, true);
305			}
306
307			/**
308			* This function performs the required checks on the authData (REG) or authenticatorData (AUTH) structure
309			*
310			* I.e. it performs
311			* - for a REGistration session
312			* - the validation steps 10-12 of the validation
313			* - the parts of step 14 that relate to authData
314			* - for a AUTHentication session
315			* - the validation steps 12-14 of the validation
316			* - the parts of step 15 that relate to authData
317			*
318			* @param string $authData the authData / authenticatorData binary blob
319			*
320			* @return int the current counter value of the authenticator
321			*/
322			private function validateAuthData(string $authData): int
323			{
324			$this->debugBuffer .= "AuthData: <pre>";
325			$this->debugBuffer .= print_r($authData, true);
326			$this->debugBuffer .= "</pre>";
327
328			/**
329			* §7.1 STEP 10: compare incoming RpId hash with expected value
330			* §7.2 STEP 12: compare incoming RpId hash with expected value
331			*/
332			if (bin2hex(substr($authData, 0, 32)) == hash("sha256", $this->scope)) {
333			$this->pass("Relying Party hash correct.");
334			$this->rpIdHash = hash("sha256", $this->scope);
335			} else {
336			$this->fail("Mismatching Relying Party hash.");
337			}
338			$bitfield = substr($authData, 32, 1);
339
340			/**
341			* §7.1 STEP 14 (authData part): no extensions were requested, so none are allowed to be present
342			* §7.2 STEP 15 (authData part): no extensions were requested, so none are allowed to be present
343			*/
344			if ((128 & ord($bitfield)) > 0) {
345			// so we get Extensions. We typically ignore all, but the
346			// "credProtect" one may be interesting in the future.
347			$this->pass("ED: Extension Data included. Interesting bits may be extracted later.");
348			} else {
349			$this->pass("ED: Extension Data not present.");
350			}
351
352			switch ($this->eventType) {
353			case "REG":
354			if ((64 & ord($bitfield)) > 0) {
355			$this->pass("AT: Attested Credential Data Included.");
356			} else {
357			$this->fail("AT: not present, but required during registration.");
358			}
359			// REG events parse their registration-related Extensions, if
360			// any, in the WebAuthnRegistrationEvent subclass
361			break;
362			case "AUTH":
363			if ((64 & ord($bitfield)) > 0) {
364			$this->fail("AT: Attested Credential Data Included.");
365			} else {
366			$this->pass("AT: not present, like it should be during an authentication.");
367			}
368			// AUTH events can also have extensions. Extensions, if any,
369			// would follow after the counter. We allow them to be present
370			// but don't currently do anything with them, so let's
371			// just make a useless extraction here as a reminder.
372			$extensionBytes = substr($authData, 37);
373			if (strlen($extensionBytes) > 0) {
374			// assign into variable and process if needed
375			$this->cborDecode($extensionBytes);
376			}
377			break;
378			default:
379			$this->fail("unknown type of operation!");
380			break;
381			}
382
383			/**
384			* §7.1 STEP 11 + 12 : check user presence (this implementation does not insist on verification currently)
385			* §7.2 STEP 13 + 14 : check user presence (this implementation does not insist on verification currently)
386			*/
387			if ((4 & ord($bitfield)) > 0) {
388			$this->presenceLevel = self::PRESENCE_LEVEL_VERIFIED;
389			$this->pass("UV indicated: User is personally identified by the token.");
390			} elseif ((1 & ord($bitfield)) > 0) {
391			$this->presenceLevel = self::PRESENCE_LEVEL_PRESENT;
392			$this->pass("UP indicated: someone is present and triggered the token.");
393			} else {
394			$this->fail("Neither UV nor UP asserted: user is possibly not present at computer.");
395			}
396			$counterBin = substr($authData, 33, 4);
397
398			$counterDec = intval(bin2hex($counterBin), 16);
399			$this->debugBuffer .= "Signature Counter: $counterDec<br/>";
400			return $counterDec;
401			}
402
403			/**
404			* this function takes a binary CBOR blob and decodes it into an associative PHP array.
405			*
406			* @param string $rawData the binary CBOR blob
407			* @return array the decoded CBOR data
408			*/
409			protected function cborDecode(string $rawData): array
410			{
411			$otherObjectManager = new OtherObject\OtherObjectManager();
412			$otherObjectManager->add(OtherObject\SimpleObject::class);
413			$otherObjectManager->add(OtherObject\FalseObject::class);
414			$otherObjectManager->add(OtherObject\TrueObject::class);
415			$otherObjectManager->add(OtherObject\NullObject::class);
416			$otherObjectManager->add(OtherObject\UndefinedObject::class);
417			$otherObjectManager->add(OtherObject\HalfPrecisionFloatObject::class);
418			$otherObjectManager->add(OtherObject\SinglePrecisionFloatObject::class);
419			$otherObjectManager->add(OtherObject\DoublePrecisionFloatObject::class);
420
421			$tagManager = new Tag\TagManager();
422			$tagManager->add(Tag\DatetimeTag::class);
423			$tagManager->add(Tag\TimestampTag::class);
424			$tagManager->add(Tag\UnsignedBigIntegerTag::class);
425			$tagManager->add(Tag\NegativeBigIntegerTag::class);
426			$tagManager->add(Tag\DecimalFractionTag::class);
427			$tagManager->add(Tag\BigFloatTag::class);
428			$tagManager->add(Tag\Base64UrlEncodingTag::class);
429			$tagManager->add(Tag\Base64EncodingTag::class);
430			$tagManager->add(Tag\Base16EncodingTag::class);
431
432			$decoder = new Decoder($tagManager, $otherObjectManager);
433			$stream = new StringStream($rawData);
434
435			$finalData = $decoder->decode($stream);
436			if ($finalData implements Normalized) {
			0 ignored issues – show Bug introduced 2024-08-13 10:12 UTC by Report Bug Copy Issue Report A parse error occurred: Syntax error, unexpected T_IMPLEMENTS on line 436 at column 23 Loading history...
437			$finalData = $finalData->normalize();
438			}
439
440			if ($finalData === null) {
441			$this->fail("CBOR data decoding failed.");
442			}
443			return $finalData;
444			}
445
446			/**
447			* @param string $text
448			* @return void
449			*/
450			protected function warn(string $text): void
451			{
452			$this->validateBuffer .= "<span style='background-color:yellow;'>WARN: $text</span><br/>";
453			}
454
455			/**
456			* @param string $text
457			* @throws \Exception
458			* @return void
459			*/
460			protected function fail(string $text): void
461			{
462			$this->validateBuffer .= "<span style='background-color:red;'>FAIL: $text</span><br/>";
463			if ($this->debugMode === true) {
464			echo $this->debugBuffer;
465			echo $this->validateBuffer;
466			}
467			throw new \Exception($text);
468			}
469
470			/**
471			* @param string $text
472			* @return void
473			*/
474			protected function pass(string $text): void
475			{
476			$this->validateBuffer .= "<span style='background-color:green; color:white;'>PASS: $text</span><br/>";
477			}
478
479			/**
480			* @param string $text
481			* @return void
482			*/
483			protected function ignore(string $text): void
484			{
485			$this->validateBuffer .= "<span style='background-color:blue; color:white;'>IGNORE: $text</span><br/>";
486			}
487			}
488

simplesamlphp / simplesamlphp-module-webauthn

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WebAuthnAbstractEvent::cborDecode() A

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