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Diffstat (limited to 'config/haproxy-devel/isCertSigner.inc')
| -rw-r--r-- | config/haproxy-devel/isCertSigner.inc | 361 |
1 files changed, 361 insertions, 0 deletions
diff --git a/config/haproxy-devel/isCertSigner.inc b/config/haproxy-devel/isCertSigner.inc new file mode 100644 index 00000000..d964129f --- /dev/null +++ b/config/haproxy-devel/isCertSigner.inc @@ -0,0 +1,361 @@ +<?php +/** + * Is one pem encoded certificate the signer of another? + * + * The PHP openssl functionality is severely limited by the lack of a stable + * api and documentation that might as well have been encrypted itself. + * In particular the documention on openssl_verify() never explains where + * to get the actual signature to verify. The isCertSigner() function below + * will accept two PEM encoded certs as arguments and will return true if + * one certificate was used to sign the other. It only relies on the + * openssl_pkey_get_public() and openssl_public_decrypt() openssl functions, + * which should stay fairly stable. The ASN parsing code snippets were mostly + * borrowed from the horde project's smime.php. + * + * @author Mike Green <mikey at badpenguins dot com> + * @copyright Copyright (c) 2010, Mike Green + * @license http://opensource.org/licenses/gpl-2.0.php GPLv2 + */ + +/** + * If viewSource is in the request string, show the source, luke. + */ +if (isset($_REQUEST['viewSource'])) { + die(highlight_file(__FILE__)); + } + +/** + * Extract signature from der encoded cert. + * Expects x509 der encoded certificate consisting of a section container + * containing 2 sections and a bitstream. The bitstream contains the + * original encrypted signature, encrypted by the public key of the issuing + * signer. + * @param string $der + * @return string on success + * @return bool false on failures + */ +function extractSignature($der=false) { + if (strlen($der) < 5) { return false; } + // skip container sequence + $der = substr($der,4); + // now burn through two sequences and the return the final bitstream + while(strlen($der) > 1) { + $class = ord($der[0]); + $classHex = dechex($class); + switch($class) { + // BITSTREAM + case 0x03: + $len = ord($der[1]); + $bytes = 0; + if ($len & 0x80) { + $bytes = $len & 0x0f; + $len = 0; + for ($i = 0; $i < $bytes; $i++) { + $len = ($len << 8) | ord($der[$i + 2]); + } + } + return substr($der,3 + $bytes, $len); + break; + // SEQUENCE + case 0x30: + $len = ord($der[1]); + $bytes = 0; + if ($len & 0x80) { + $bytes = $len & 0x0f; + $len = 0; + for($i = 0; $i < $bytes; $i++) { + $len = ($len << 8) | ord($der[$i + 2]); + } + } + $contents = substr($der, 2 + $bytes, $len); + $der = substr($der,2 + $bytes + $len); + break; + default: + return false; + break; + } + } + return false; + } + +/** + * Get signature algorithm oid from der encoded signature data. + * Expects decrypted signature data from a certificate in der format. + * This ASN1 data should contain the following structure: + * SEQUENCE + * SEQUENCE + * OID (signature algorithm) + * NULL + * OCTET STRING (signature hash) + * @return bool false on failures + * @return string oid + */ +function getSignatureAlgorithmOid($der=null) { + // Validate this is the der we need... + if (!is_string($der) or strlen($der) < 5) { return false; } + $bit_seq1 = 0; + $bit_seq2 = 2; + $bit_oid = 4; + if (ord($der[$bit_seq1]) !== 0x30) { + die('Invalid DER passed to getSignatureAlgorithmOid()'); + } + if (ord($der[$bit_seq2]) !== 0x30) { + die('Invalid DER passed to getSignatureAlgorithmOid()'); + } + if (ord($der[$bit_oid]) !== 0x06) { + die('Invalid DER passed to getSignatureAlgorithmOid'); + } + // strip out what we don't need and get the oid + $der = substr($der,$bit_oid); + // Get the oid + $len = ord($der[1]); + $bytes = 0; + if ($len & 0x80) { + $bytes = $len & 0x0f; + $len = 0; + for ($i = 0; $i < $bytes; $i++) { + $len = ($len << 8) | ord($der[$i + 2]); + } + } + $oid_data = substr($der, 2 + $bytes, $len); + // Unpack the OID + $oid = floor(ord($oid_data[0]) / 40); + $oid .= '.' . ord($oid_data[0]) % 40; + $value = 0; + $i = 1; + while ($i < strlen($oid_data)) { + $value = $value << 7; + $value = $value | (ord($oid_data[$i]) & 0x7f); + if (!(ord($oid_data[$i]) & 0x80)) { + $oid .= '.' . $value; + $value = 0; + } + $i++; + } + return $oid; + } + +/** + * Get signature hash from der encoded signature data. + * Expects decrypted signature data from a certificate in der format. + * This ASN1 data should contain the following structure: + * SEQUENCE + * SEQUENCE + * OID (signature algorithm) + * NULL + * OCTET STRING (signature hash) + * @return bool false on failures + * @return string hash + */ +function getSignatureHash($der=null) { + // Validate this is the der we need... + if (!is_string($der) or strlen($der) < 5) { return false; } + if (ord($der[0]) !== 0x30) { + die('Invalid DER passed to getSignatureHash()'); + } + // strip out the container sequence + $der = substr($der,2); + if (ord($der[0]) !== 0x30) { + die('Invalid DER passed to getSignatureHash()'); + } + // Get the length of the first sequence so we can strip it out. + $len = ord($der[1]); + $bytes = 0; + if ($len & 0x80) { + $bytes = $len & 0x0f; + $len = 0; + for ($i = 0; $i < $bytes; $i++) { + $len = ($len << 8) | ord($der[$i + 2]); + } + } + $der = substr($der, 2 + $bytes + $len); + // Now we should have an octet string + if (ord($der[0]) !== 0x04) { + die('Invalid DER passed to getSignatureHash()'); + } + $len = ord($der[1]); + $bytes = 0; + if ($len & 0x80) { + $bytes = $len & 0x0f; + $len = 0; + for ($i = 0; $i < $bytes; $i++) { + $len = ($len << 8) | ord($der[$i + 2]); + } + } + return bin2hex(substr($der, 2 + $bytes, $len)); + } + +/** + * Determine if one cert was used to sign another + * Note that more than one CA cert can give a positive result, some certs + * re-issue signing certs after having only changed the expiration dates. + * @param string $cert - PEM encoded cert + * @param string $caCert - PEM encoded cert that possibly signed $cert + * @return bool + */ +function isCertSigner($certPem=null,$caCertPem=null) { + if (!function_exists('openssl_pkey_get_public')) { + die('Need the openssl_pkey_get_public() function.'); + } + if (!function_exists('openssl_public_decrypt')) { + die('Need the openssl_public_decrypt() function.'); + } + if (!function_exists('hash')) { + die('Need the php hash() function.'); + } + if (empty($certPem) or empty($caCertPem)) { return false; } + // Convert the cert to der for feeding to extractSignature. + $certDer = pemToDer($certPem); + if (!is_string($certDer)) { die('invalid certPem'); } + // Grab the encrypted signature from the der encoded cert. + $encryptedSig = extractSignature($certDer); + if (!is_string($encryptedSig)) { + die('Failed to extract encrypted signature from certPem.'); + } + // Extract the public key from the ca cert, which is what has + // been used to encrypt the signature in the cert. + $pubKey = openssl_pkey_get_public($caCertPem); + if ($pubKey === false) { + die('Failed to extract the public key from the ca cert.'); + } + // Attempt to decrypt the encrypted signature using the CA's public + // key, returning the decrypted signature in $decryptedSig. If + // it can't be decrypted, this ca was not used to sign it for sure... + $rc = openssl_public_decrypt($encryptedSig,$decryptedSig,$pubKey); + if ($rc === false) { return false; } + // We now have the decrypted signature, which is der encoded + // asn1 data containing the signature algorithm and signature hash. + // Now we need what was originally hashed by the issuer, which is + // the original DER encoded certificate without the issuer and + // signature information. + $origCert = stripSignerAsn($certDer); + if ($origCert === false) { + die('Failed to extract unsigned cert.'); + } + // Get the oid of the signature hash algorithm, which is required + // to generate our own hash of the original cert. This hash is + // what will be compared to the issuers hash. + $oid = getSignatureAlgorithmOid($decryptedSig); + if ($oid === false) { + die('Failed to determine the signature algorithm.'); + } + switch($oid) { + case '1.2.840.113549.2.2': $algo = 'md2'; break; + case '1.2.840.113549.2.4': $algo = 'md4'; break; + case '1.2.840.113549.2.5': $algo = 'md5'; break; + case '1.3.14.3.2.18': $algo = 'sha'; break; + case '1.3.14.3.2.26': $algo = 'sha1'; break; + case '2.16.840.1.101.3.4.2.1': $algo = 'sha256'; break; + case '2.16.840.1.101.3.4.2.2': $algo = 'sha384'; break; + case '2.16.840.1.101.3.4.2.3': $algo = 'sha512'; break; + default: + die('Unknown signature hash algorithm oid: ' . $oid); + break; + } + // Get the issuer generated hash from the decrypted signature. + $decryptedHash = getSignatureHash($decryptedSig); + // Ok, hash the original unsigned cert with the same algorithm + // and if it matches $decryptedHash we have a winner. + $certHash = hash($algo,$origCert); + return ($decryptedHash === $certHash); + } + +/** + * Convert pem encoded certificate to DER encoding + * @return string $derEncoded on success + * @return bool false on failures + */ +function pemToDer($pem=null) { + if (!is_string($pem)) { return false; } + $cert_split = preg_split('/(-----((BEGIN)|(END)) CERTIFICATE-----)/',$pem); + if (!isset($cert_split[1])) { return false; } + return base64_decode($cert_split[1]); + } + +/** + * Obtain der cert with issuer and signature sections stripped. + * @param string $der - der encoded certificate + * @return string $der on success + * @return bool false on failures. + */ +function stripSignerAsn($der=null) { + if (!is_string($der) or strlen($der) < 8) { return false; } + $bit = 4; + $len = ord($der[($bit + 1)]); + $bytes = 0; + if ($len & 0x80) { + $bytes = $len & 0x0f; + $len = 0; + for($i = 0; $i < $bytes; $i++) { + $len = ($len << 8) | ord($der[$bit + $i + 2]); + } + } + return substr($der,4,$len + 4); + } +/* +/ ** + * HTML form starts here... + * / + +$answer = 'Enter PEM Encoded Certificates for the Issuer and Subject ' + . 'and click Submit. Include the entire certificates, including ' + . 'the BEGIN CERTIFICATE and END CERTIFICATE lines.'; + +if (isset($_POST['subjectPem']) and isset($_POST['issuerPem'])) { + if (strlen($_POST['subjectPem']) > 0 and strlen($_POST['issuerPem']) > 0) { + $rc = isCertSigner($_POST['subjectPem'],$_POST['issuerPem']); + if ($rc === true) { + $answer = 'The issuer cert DID sign the subject cert.'; + } else { + $answer = 'The issuer cert DID NOT sign the subject cert.'; + } + } + } +?> +<HTML> +<BODY BGCOLOR="white"> +<HEAD> +<TITLE>Is This The Cert Signer?</TITLE> +<STYLE TYPE="text/css"> +textarea { + font-size: 11px; + } +</STYLE> +</HEAD> +<BODY> +<DIV ALIGN="center"> +<FORM NAME="check_certs" METHOD="post" action="<?= $_SERVER['PHP_SELF']; ?>"> +<TABLE BORDER="1" WIDTH="500px"> + <TR> + <TD><?= $answer; ?></TD> + </TR> + <TR> + <TH>Issuer Certificate (<A HREF="#" ONCLICK="javascript:document.check_certs.issuerPem.value='';">clear</A>)</TH> + </TR> + <TR> + <TD> + <TEXTAREA NAME="issuerPem" ROWS="20" COLS="70"><?= (isset($_POST['issuerPem'])) ? $_POST['issuerPem'] : ''; ?></TEXTAREA> + </TD> + </TR> + <TR> + <TH>Subject Certificate (<A HREF="#" ONCLICK="javascript:document.check_certs.subjectPem.value='';">clear</A>)</TH> + </TR> + <TR> + <TD> + <TEXTAREA NAME="subjectPem" ROWS="20" COLS="70"><?= (isset($_POST['subjectPem'])) ? $_POST['subjectPem'] : ''; ?></TEXTAREA> + </TD> + </TR> + <TR> + <TD ALIGN="right"> + (<A HREF="<?= $_SERVER['PHP_SELF']; ?>?viewSource">view source</A>) + <INPUT TYPE="submit" NAME="submit" VALUE="submit"> + </TD> + </TR> +</TABLE> +</FORM> +</DIV> +</BODY> +</HTML> + +*/ +?>
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