410 lines
12 KiB
C#
410 lines
12 KiB
C#
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//
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// X509CRL.cs: Handles X.509 certificates revocation lists.
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//
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// Author:
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// Sebastien Pouliot <sebastien@xamarin.com>
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//
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// Copyright (C) 2004,2006 Novell Inc. (http://www.novell.com)
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// Copyright 2013 Xamarin Inc. (http://www.xamarin.com)
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//
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// Permission is hereby granted, free of charge, to any person obtaining
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// a copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to
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// permit persons to whom the Software is furnished to do so, subject to
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// the following conditions:
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//
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// The above copyright notice and this permission notice shall be
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// included in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
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// LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
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// OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
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// WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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//
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using System;
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using System.Collections;
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using System.Globalization;
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using System.IO;
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using System.Security.Cryptography;
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using Mono.Security.Cryptography;
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using Mono.Security.X509.Extensions;
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namespace Mono.Security.X509 {
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/*
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* CertificateList ::= SEQUENCE {
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* tbsCertList TBSCertList,
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* signatureAlgorithm AlgorithmIdentifier,
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* signature BIT STRING
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* }
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*
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* TBSCertList ::= SEQUENCE {
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* version Version OPTIONAL,
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* -- if present, MUST be v2
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* signature AlgorithmIdentifier,
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* issuer Name,
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* thisUpdate Time,
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* nextUpdate Time OPTIONAL,
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* revokedCertificates SEQUENCE OF SEQUENCE {
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* userCertificate CertificateSerialNumber,
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* revocationDate Time,
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* crlEntryExtensions Extensions OPTIONAL
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* -- if present, MUST be v2
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* } OPTIONAL,
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* crlExtensions [0] Extensions OPTIONAL }
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* -- if present, MUST be v2
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*/
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#if !INSIDE_CORLIB
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public
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#endif
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class X509Crl {
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public class X509CrlEntry {
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private byte[] sn;
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private DateTime revocationDate;
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private X509ExtensionCollection extensions;
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internal X509CrlEntry (byte[] serialNumber, DateTime revocationDate, X509ExtensionCollection extensions)
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{
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sn = serialNumber;
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this.revocationDate = revocationDate;
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if (extensions == null)
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this.extensions = new X509ExtensionCollection ();
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else
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this.extensions = extensions;
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}
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internal X509CrlEntry (ASN1 entry)
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{
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sn = entry [0].Value;
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Array.Reverse (sn);
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revocationDate = ASN1Convert.ToDateTime (entry [1]);
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extensions = new X509ExtensionCollection (entry [2]);
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}
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public byte[] SerialNumber {
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get { return (byte[]) sn.Clone (); }
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}
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public DateTime RevocationDate {
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get { return revocationDate; }
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}
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public X509ExtensionCollection Extensions {
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get { return extensions; }
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}
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public byte[] GetBytes ()
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{
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ASN1 sequence = new ASN1 (0x30);
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sequence.Add (new ASN1 (0x02, sn));
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sequence.Add (ASN1Convert.FromDateTime (revocationDate));
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if (extensions.Count > 0)
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sequence.Add (new ASN1 (extensions.GetBytes ()));
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return sequence.GetBytes ();
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}
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}
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private string issuer;
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private byte version;
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private DateTime thisUpdate;
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private DateTime nextUpdate;
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private ArrayList entries;
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private string signatureOID;
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private byte[] signature;
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private X509ExtensionCollection extensions;
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private byte[] encoded;
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private byte[] hash_value;
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public X509Crl (byte[] crl)
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{
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if (crl == null)
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throw new ArgumentNullException ("crl");
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encoded = (byte[]) crl.Clone ();
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Parse (encoded);
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}
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private void Parse (byte[] crl)
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{
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string e = "Input data cannot be coded as a valid CRL.";
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try {
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// CertificateList ::= SEQUENCE {
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ASN1 encodedCRL = new ASN1 (encoded);
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if ((encodedCRL.Tag != 0x30) || (encodedCRL.Count != 3))
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throw new CryptographicException (e);
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// CertificateList / TBSCertList,
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ASN1 toBeSigned = encodedCRL [0];
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if ((toBeSigned.Tag != 0x30) || (toBeSigned.Count < 3))
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throw new CryptographicException (e);
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int n = 0;
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// CertificateList / TBSCertList / Version OPTIONAL, -- if present, MUST be v2
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if (toBeSigned [n].Tag == 0x02) {
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version = (byte) (toBeSigned [n++].Value [0] + 1);
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}
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else
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version = 1; // DEFAULT
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// CertificateList / TBSCertList / AlgorithmIdentifier,
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signatureOID = ASN1Convert.ToOid (toBeSigned [n++][0]);
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// CertificateList / TBSCertList / Name,
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issuer = X501.ToString (toBeSigned [n++]);
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// CertificateList / TBSCertList / Time,
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thisUpdate = ASN1Convert.ToDateTime (toBeSigned [n++]);
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// CertificateList / TBSCertList / Time OPTIONAL,
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ASN1 next = toBeSigned [n++];
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if ((next.Tag == 0x17) || (next.Tag == 0x18)) {
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nextUpdate = ASN1Convert.ToDateTime (next);
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next = toBeSigned [n++];
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}
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// CertificateList / TBSCertList / revokedCertificates SEQUENCE OF SEQUENCE {
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entries = new ArrayList ();
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// this is OPTIONAL so it may not be present if no entries exists
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if ((next != null) && (next.Tag == 0x30)) {
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ASN1 revokedCertificates = next;
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for (int i=0; i < revokedCertificates.Count; i++) {
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entries.Add (new X509CrlEntry (revokedCertificates [i]));
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}
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} else {
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n--;
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}
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// CertificateList / TBSCertList / crlExtensions [0] Extensions OPTIONAL }
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ASN1 extns = toBeSigned [n];
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if ((extns != null) && (extns.Tag == 0xA0) && (extns.Count == 1))
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extensions = new X509ExtensionCollection (extns [0]);
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else
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extensions = new X509ExtensionCollection (null); // result in a read only object
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// CertificateList / AlgorithmIdentifier
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string signatureAlgorithm = ASN1Convert.ToOid (encodedCRL [1][0]);
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if (signatureOID != signatureAlgorithm)
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throw new CryptographicException (e + " [Non-matching signature algorithms in CRL]");
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// CertificateList / BIT STRING
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byte[] bitstring = encodedCRL [2].Value;
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// first byte contains unused bits in first byte
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signature = new byte [bitstring.Length - 1];
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Buffer.BlockCopy (bitstring, 1, signature, 0, signature.Length);
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}
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catch {
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throw new CryptographicException (e);
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}
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}
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public ArrayList Entries {
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get { return ArrayList.ReadOnly (entries); }
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}
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public X509CrlEntry this [int index] {
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get { return (X509CrlEntry) entries [index]; }
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}
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public X509CrlEntry this [byte[] serialNumber] {
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get { return GetCrlEntry (serialNumber); }
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}
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public X509ExtensionCollection Extensions {
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get { return extensions; }
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}
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public byte[] Hash {
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get {
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if (hash_value == null) {
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ASN1 encodedCRL = new ASN1 (encoded);
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byte[] toBeSigned = encodedCRL [0].GetBytes ();
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using (var ha = PKCS1.CreateFromOid (signatureOID))
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hash_value = ha.ComputeHash (toBeSigned);
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}
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return hash_value;
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}
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}
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public string IssuerName {
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get { return issuer; }
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}
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public DateTime NextUpdate {
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get { return nextUpdate; }
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}
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public DateTime ThisUpdate {
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get { return thisUpdate; }
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}
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public string SignatureAlgorithm {
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get { return signatureOID; }
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}
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public byte[] Signature {
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get {
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if (signature == null)
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return null;
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return (byte[]) signature.Clone ();
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}
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}
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public byte[] RawData {
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get { return (byte[]) encoded.Clone (); }
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}
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public byte Version {
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get { return version; }
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}
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public bool IsCurrent {
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get { return WasCurrent (DateTime.Now); }
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}
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public bool WasCurrent (DateTime instant)
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{
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if (nextUpdate == DateTime.MinValue)
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return (instant >= thisUpdate);
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else
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return ((instant >= thisUpdate) && (instant <= nextUpdate));
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}
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public byte[] GetBytes ()
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{
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return (byte[]) encoded.Clone ();
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}
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private bool Compare (byte[] array1, byte[] array2)
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{
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if ((array1 == null) && (array2 == null))
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return true;
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if ((array1 == null) || (array2 == null))
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return false;
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if (array1.Length != array2.Length)
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return false;
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for (int i=0; i < array1.Length; i++) {
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if (array1 [i] != array2 [i])
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return false;
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}
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return true;
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}
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public X509CrlEntry GetCrlEntry (X509Certificate x509)
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{
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if (x509 == null)
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throw new ArgumentNullException ("x509");
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return GetCrlEntry (x509.SerialNumber);
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}
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public X509CrlEntry GetCrlEntry (byte[] serialNumber)
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{
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if (serialNumber == null)
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throw new ArgumentNullException ("serialNumber");
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for (int i=0; i < entries.Count; i++) {
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X509CrlEntry entry = (X509CrlEntry) entries [i];
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if (Compare (serialNumber, entry.SerialNumber))
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return entry;
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}
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return null;
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}
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public bool VerifySignature (X509Certificate x509)
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{
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if (x509 == null)
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throw new ArgumentNullException ("x509");
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// 1. x509 certificate must be a CA certificate (unknown for v1 or v2 certs)
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if (x509.Version >= 3) {
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BasicConstraintsExtension basicConstraints = null;
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// 1.2. Check for ca = true in BasicConstraint
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X509Extension ext = x509.Extensions ["2.5.29.19"];
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if (ext != null) {
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basicConstraints = new BasicConstraintsExtension (ext);
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if (!basicConstraints.CertificateAuthority)
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return false;
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}
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// 1.1. Check for "cRLSign" bit in KeyUsage extension
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ext = x509.Extensions ["2.5.29.15"];
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if (ext != null) {
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KeyUsageExtension keyUsage = new KeyUsageExtension (ext);
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if (!keyUsage.Support (KeyUsages.cRLSign)) {
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// 2nd chance if basicConstraints is CertificateAuthority
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// and KeyUsage support digitalSignature
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if ((basicConstraints == null) || !keyUsage.Support (KeyUsages.digitalSignature))
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return false;
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}
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}
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}
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// 2. CRL issuer must match CA subject name
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if (issuer != x509.SubjectName)
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return false;
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// 3. Check the CRL signature with the CA certificate public key
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switch (signatureOID) {
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case "1.2.840.10040.4.3":
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return VerifySignature (x509.DSA);
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default:
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return VerifySignature (x509.RSA);
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}
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}
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internal bool VerifySignature (DSA dsa)
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{
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if (signatureOID != "1.2.840.10040.4.3")
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throw new CryptographicException ("Unsupported hash algorithm: " + signatureOID);
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DSASignatureDeformatter v = new DSASignatureDeformatter (dsa);
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// only SHA-1 is supported
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v.SetHashAlgorithm ("SHA1");
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ASN1 sign = new ASN1 (signature);
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if ((sign == null) || (sign.Count != 2))
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return false;
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// parts may be less than 20 bytes (i.e. first bytes were 0x00)
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byte[] part1 = sign [0].Value;
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byte[] part2 = sign [1].Value;
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byte[] sig = new byte [40];
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// parts may be less than 20 bytes (i.e. first bytes were 0x00)
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// parts may be more than 20 bytes (i.e. first byte > 0x80, negative)
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int s1 = System.Math.Max (0, part1.Length - 20);
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int e1 = System.Math.Max (0, 20 - part1.Length);
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Buffer.BlockCopy (part1, s1, sig, e1, part1.Length - s1);
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int s2 = System.Math.Max (0, part2.Length - 20);
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int e2 = System.Math.Max (20, 40 - part2.Length);
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Buffer.BlockCopy (part2, s2, sig, e2, part2.Length - s2);
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return v.VerifySignature (Hash, sig);
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}
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internal bool VerifySignature (RSA rsa)
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{
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RSAPKCS1SignatureDeformatter v = new RSAPKCS1SignatureDeformatter (rsa);
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v.SetHashAlgorithm (PKCS1.HashNameFromOid (signatureOID));
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return v.VerifySignature (Hash, signature);
|
||
|
|
}
|
||
|
|
|
||
|
|
public bool VerifySignature (AsymmetricAlgorithm aa)
|
||
|
|
{
|
||
|
|
if (aa == null)
|
||
|
|
throw new ArgumentNullException ("aa");
|
||
|
|
|
||
|
|
// only validate the signature (in case we don't have the CA certificate)
|
||
|
|
if (aa is RSA)
|
||
|
|
return VerifySignature (aa as RSA);
|
||
|
|
else if (aa is DSA)
|
||
|
|
return VerifySignature (aa as DSA);
|
||
|
|
else
|
||
|
|
throw new NotSupportedException ("Unknown Asymmetric Algorithm " + aa.ToString ());
|
||
|
|
}
|
||
|
|
|
||
|
|
static public X509Crl CreateFromFile (string filename)
|
||
|
|
{
|
||
|
|
byte[] crl = null;
|
||
|
|
using (FileStream fs = File.Open (filename, FileMode.Open, FileAccess.Read, FileShare.Read)) {
|
||
|
|
crl = new byte [fs.Length];
|
||
|
|
fs.Read (crl, 0, crl.Length);
|
||
|
|
fs.Close ();
|
||
|
|
}
|
||
|
|
return new X509Crl (crl);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
}
|