Merge pull request #1450 from hifi/feature/sshagent-old-keys

SSH Agent: Support old unencrypted DSA and RSA keys

src/gui/entry/EditEntryWidget.cpp

@@ -444,6 +444,10 @@ bool EditEntryWidget::getOpenSSHKey(OpenSSHKey& key)
         return false;
     }
 
+    if (key.comment().isEmpty()) {
+        key.setComment(m_entry->username());
+    }
+
     return true;
 }
 

src/sshagent/ASN1Key.cpp

@@ -0,0 +1,186 @@
+/*
+ *  Copyright (C) 2018 Toni Spets <toni.spets@iki.fi>
+ *  Copyright (C) 2018 KeePassXC Team <team@keepassxc.org>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 2 or (at your option)
+ *  version 3 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "ASN1Key.h"
+#include <gcrypt.h>
+
+namespace {
+    constexpr quint8 TAG_INT         = 0x02;
+    constexpr quint8 TAG_SEQUENCE    = 0x30;
+    constexpr quint8 KEY_ZERO        = 0x0;
+
+    bool nextTag(BinaryStream& stream, quint8& tag, quint32& len)
+    {
+        stream.read(tag);
+
+        quint8 lenByte;
+        stream.read(lenByte);
+
+        if (lenByte & 0x80) {
+            quint32 bytes = lenByte & ~0x80;
+            if (bytes == 1) {
+                stream.read(lenByte);
+                len = lenByte;
+            } else if (bytes == 2) {
+                quint16 lenShort;
+                stream.read(lenShort);
+                len = lenShort;
+            } else if (bytes == 4) {
+                stream.read(len);
+            } else {
+                return false;
+            }
+        } else {
+            len = lenByte;
+        }
+
+        return true;
+    }
+
+    bool parseHeader(BinaryStream& stream, quint8 wantedType)
+    {
+        quint8 tag;
+        quint32 len;
+
+        nextTag(stream, tag, len);
+
+        if (tag != TAG_SEQUENCE) {
+            return false;
+        }
+
+        nextTag(stream, tag, len);
+
+        if (tag != TAG_INT || len != 1) {
+            return false;
+        }
+
+        quint8 keyType;
+        stream.read(keyType);
+
+        return (keyType == wantedType);
+    }
+
+    bool readInt(BinaryStream& stream, QByteArray& target)
+    {
+        quint8 tag;
+        quint32 len;
+
+        nextTag(stream, tag, len);
+
+        if (tag != TAG_INT) {
+            return false;
+        }
+
+        target.resize(len);
+        stream.read(target);
+        return true;
+    }
+
+    QByteArray calculateIqmp(QByteArray& bap, QByteArray& baq)
+    {
+        gcry_mpi_t u, p, q;
+        QByteArray iqmp_hex;
+
+        u = gcry_mpi_snew(bap.length() * 8);
+        gcry_mpi_scan(&p, GCRYMPI_FMT_HEX, bap.toHex().data(), 0, nullptr);
+        gcry_mpi_scan(&q, GCRYMPI_FMT_HEX, baq.toHex().data(), 0, nullptr);
+
+        mpi_invm(u, q, p);
+
+        iqmp_hex.resize((bap.length() + 1) * 2);
+        gcry_mpi_print(GCRYMPI_FMT_HEX, reinterpret_cast<unsigned char*>(iqmp_hex.data()), iqmp_hex.length(), nullptr, u);
+
+        gcry_mpi_release(u);
+        gcry_mpi_release(p);
+        gcry_mpi_release(q);
+
+        return QByteArray::fromHex(iqmp_hex);
+    }
+}
+
+bool ASN1Key::parseDSA(QByteArray& ba, OpenSSHKey& key)
+{
+    BinaryStream stream(&ba);
+
+    if (!parseHeader(stream, KEY_ZERO)) {
+        return false;
+    }
+
+    QByteArray p,q,g,y,x;
+    readInt(stream, p);
+    readInt(stream, q);
+    readInt(stream, g);
+    readInt(stream, y);
+    readInt(stream, x);
+
+    QList<QByteArray> publicData;
+    publicData.append(p);
+    publicData.append(q);
+    publicData.append(g);
+    publicData.append(y);
+
+    QList<QByteArray> privateData;
+    privateData.append(p);
+    privateData.append(q);
+    privateData.append(g);
+    privateData.append(y);
+    privateData.append(x);
+
+    key.setType("ssh-dss");
+    key.setPublicData(publicData);
+    key.setPrivateData(privateData);
+    key.setComment("");
+    return true;
+}
+
+bool ASN1Key::parseRSA(QByteArray& ba, OpenSSHKey& key)
+{
+    BinaryStream stream(&ba);
+
+    if (!parseHeader(stream, KEY_ZERO)) {
+        return false;
+    }
+
+    QByteArray n,e,d,p,q,dp,dq,qinv;
+    readInt(stream, n);
+    readInt(stream, e);
+    readInt(stream, d);
+    readInt(stream, p);
+    readInt(stream, q);
+    readInt(stream, dp);
+    readInt(stream, dq);
+    readInt(stream, qinv);
+
+    QList<QByteArray> publicData;
+    publicData.append(e);
+    publicData.append(n);
+
+    QList<QByteArray> privateData;
+    privateData.append(n);
+    privateData.append(e);
+    privateData.append(d);
+    privateData.append(calculateIqmp(p, q));
+    privateData.append(p);
+    privateData.append(q);
+
+    key.setType("ssh-rsa");
+    key.setPublicData(publicData);
+    key.setPrivateData(privateData);
+    key.setComment("");
+    return true;
+}

src/sshagent/ASN1Key.h

@@ -0,0 +1,31 @@
+/*
+ *  Copyright (C) 2018 Toni Spets <toni.spets@iki.fi>
+ *  Copyright (C) 2018 KeePassXC Team <team@keepassxc.org>
+ *
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 2 or (at your option)
+ *  version 3 of the License.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef ASN1KEY_H
+#define ASN1KEY_H
+
+#include "OpenSSHKey.h"
+#include <QtCore>
+
+namespace ASN1Key
+{
+    bool parseDSA(QByteArray& ba, OpenSSHKey& key);
+    bool parseRSA(QByteArray& ba, OpenSSHKey& key);
+}
+
+#endif // ASN1KEY_H

src/sshagent/CMakeLists.txt

@@ -9,6 +9,7 @@ if(WITH_XC_SSHAGENT)
         BinaryStream.cpp
         KeeAgentSettings.cpp
         OpenSSHKey.cpp
+        ASN1Key.cpp
         SSHAgent.cpp
     )
 

src/sshagent/OpenSSHKey.cpp

@@ -17,11 +17,16 @@
  */
 
 #include "OpenSSHKey.h"
+#include "ASN1Key.h"
 #include <QRegularExpression>
 #include <QStringList>
 #include <QCryptographicHash>
 #include "crypto/SymmetricCipher.h"
 
+const QString OpenSSHKey::TYPE_DSA = "DSA PRIVATE KEY";
+const QString OpenSSHKey::TYPE_RSA = "RSA PRIVATE KEY";
+const QString OpenSSHKey::TYPE_OPENSSH = "OPENSSH PRIVATE KEY";
+
 // bcrypt_pbkdf.cpp
 int bcrypt_pbkdf(const QByteArray& pass, const QByteArray& salt, QByteArray& key, quint32 rounds);
 
@@ -34,6 +39,7 @@ OpenSSHKey::OpenSSHKey(QObject *parent)
     , m_rawPrivateData(QByteArray())
     , m_publicData(QList<QByteArray>())
     , m_privateData(QList<QByteArray>())
+    , m_privateType(QString())
     , m_comment(QString())
     , m_error(QString())
 {
@@ -178,14 +184,31 @@ bool OpenSSHKey::parsePEM(const QByteArray& in, QByteArray& out)
         return false;
     }
 
-    if (beginMatch.captured(1) != "OPENSSH PRIVATE KEY") {
+    m_privateType = beginMatch.captured(1);
-        m_error = tr("This is not an OpenSSH key, only modern keys are supported");
-        return false;
-    }
 
     rows.removeFirst();
     rows.removeLast();
 
+    QRegularExpression keyValueExpr = QRegularExpression("^([A-Za-z0-9-]+): (.+)$");
+    QMap<QString, QString> pemOptions;
+
+    do {
+        QRegularExpressionMatch keyValueMatch = keyValueExpr.match(rows.first());
+
+        if (!keyValueMatch.hasMatch()) {
+            break;
+        }
+
+        pemOptions.insert(keyValueMatch.captured(1), keyValueMatch.captured(2));
+
+        rows.removeFirst();
+    } while (!rows.isEmpty());
+
+    if (pemOptions.contains("Proc-Type")) {
+        m_error = tr("Encrypted keys are not yet supported");
+        return false;
+    }
+
     out = QByteArray::fromBase64(rows.join("").toLatin1());
 
     if (out.isEmpty()) {
@@ -204,6 +227,9 @@ bool OpenSSHKey::parse(const QByteArray& in)
         return false;
     }
 
+    if (m_privateType == TYPE_DSA || m_privateType == TYPE_RSA) {
+        m_rawPrivateData = data;
+    } else if (m_privateType == TYPE_OPENSSH) {
         BinaryStream stream(&data);
 
         QByteArray magic;
@@ -251,6 +277,10 @@ bool OpenSSHKey::parse(const QByteArray& in)
             m_error = tr("Corrupted key file, reading private key failed");
             return false;
         }
+    } else {
+        m_error = tr("Unsupported key type: %s").arg(m_privateType);
+        return false;
+    }
 
     // load private if no encryption
     if (!encrypted()) {
@@ -283,7 +313,7 @@ bool OpenSSHKey::openPrivateKey(const QString& passphrase)
     } else if (m_cipherName == "aes256-ctr") {
         cipher.reset(new SymmetricCipher(SymmetricCipher::Aes256, SymmetricCipher::Ctr, SymmetricCipher::Decrypt));
     } else if (m_cipherName != "none") {
-        m_error = tr("Unknown cipher: ") + m_cipherName;
+        m_error = tr("Unknown cipher: %s").arg(m_cipherName);
         return false;
     }
 
@@ -320,8 +350,13 @@ bool OpenSSHKey::openPrivateKey(const QString& passphrase)
         ivData.setRawData(decryptKey.data() + cipher->keySize(), cipher->blockSize());
 
         cipher->init(keyData, ivData);
+
+        if (!cipher->init(keyData, ivData)) {
+            m_error = cipher->errorString();
+            return false;
+        }
     } else if (m_kdfName != "none") {
-        m_error = tr("Unknown KDF: ") + m_kdfName;
+        m_error = tr("Unknown KDF: %s").arg(m_kdfName);
         return false;
     }
 
@@ -336,6 +371,21 @@ bool OpenSSHKey::openPrivateKey(const QString& passphrase)
         }
     }
 
+    if (m_privateType == TYPE_DSA) {
+        if (!ASN1Key::parseDSA(rawPrivateData, *this)) {
+            m_error = tr("Reading DSA private key failed, only unencrypted keys are supported at this time");
+            return false;
+        }
+
+        return true;
+    } else if (m_privateType == TYPE_RSA) {
+        if (!ASN1Key::parseRSA(rawPrivateData, *this)) {
+            m_error = tr("Reading RSA private key failed, only unencrypted keys are supported at this time");
+            return false;
+        }
+
+        return true;
+    } else if (m_privateType == TYPE_OPENSSH) {
         BinaryStream keyStream(&rawPrivateData);
 
         quint32 checkInt1;
@@ -350,6 +400,10 @@ bool OpenSSHKey::openPrivateKey(const QString& passphrase)
         }
 
         return readPrivate(keyStream);
+    }
+
+    m_error = tr("Unsupported key type: %s").arg(m_privateType);
+    return false;
 }
 
 bool OpenSSHKey::readPublic(BinaryStream& stream)
@@ -371,7 +425,7 @@ bool OpenSSHKey::readPublic(BinaryStream& stream)
     } else if (m_type == "ssh-ed25519") {
         keyParts = 1;
     } else {
-        m_error = tr("Unknown key type: ") + m_type;
+        m_error = tr("Unknown key type: %s").arg(m_type);
         return false;
     }
 
@@ -408,7 +462,7 @@ bool OpenSSHKey::readPrivate(BinaryStream& stream)
     } else if (m_type == "ssh-ed25519") {
         keyParts = 2;
     } else {
-        m_error = tr("Unknown key type: ") + m_type;
+        m_error = tr("Unknown key type: %s").arg(m_type);
         return false;
     }
 

src/sshagent/OpenSSHKey.h

@@ -55,6 +55,10 @@ public:
     bool writePrivate(BinaryStream& stream);
 
 private:
+    static const QString TYPE_DSA;
+    static const QString TYPE_RSA;
+    static const QString TYPE_OPENSSH;
+
     bool parsePEM(const QByteArray& in, QByteArray& out);
 
     QString m_type;
@@ -64,6 +68,7 @@ private:
     QByteArray m_rawPrivateData;
     QList<QByteArray> m_publicData;
     QList<QByteArray> m_privateData;
+    QString m_privateType;
     QString m_comment;
     QString m_error;
 };

src/sshagent/SSHAgent.cpp

@@ -260,6 +260,10 @@ void SSHAgent::databaseModeChanged(DatabaseWidget::Mode mode)
                 continue;
             }
 
+            if (key.comment().isEmpty()) {
+                key.setComment(e->username());
+            }
+
             if (settings.removeAtDatabaseClose()) {
                 removeIdentityAtLock(key, uuid);
             }

tests/TestOpenSSHKey.cpp

@@ -50,6 +50,7 @@ void TestOpenSSHKey::testParse()
     QCOMPARE(key.cipherName(), QString("none"));
     QCOMPARE(key.type(), QString("ssh-ed25519"));
     QCOMPARE(key.comment(), QString("opensshkey-test-parse@keepassxc"));
+    QCOMPARE(key.fingerprint(), QString("SHA256:D1fVmA15YXzaJ5sdO9dXxo5coHL/pnNaIfCvokHzTA4"));
 
     QByteArray publicKey, privateKey;
     BinaryStream publicStream(&publicKey), privateStream(&privateKey);
@@ -61,6 +62,77 @@ void TestOpenSSHKey::testParse()
     QVERIFY(privateKey.length() == 154);
 }
 
+void TestOpenSSHKey::testParseDSA()
+{
+    const QString keyString = QString(
+        "-----BEGIN DSA PRIVATE KEY-----\n"
+        "MIIBuwIBAAKBgQCudjbvSh8JxQOr2laCqZM1t4kNWBETVOXz5vgk9iw6Z5opB9/k\n"
+        "g4nFc1PVq7fdAIc8W/5WCAjugKcxPb9PIHfcwY2fimmiPWFK68/eHKLoCuIn2wxB\n"
+        "63ig2hAhx5U5aYG9QHkNCaT6VX7rc19nToSeZXlpja4x54/DaQaqOEWYsQIVAOer\n"
+        "UQWfccz7KXUu6+x7heGob6I3AoGAVDRFJIlL0DI/4nePIcgwgwbfgs2ojSu21g4w\n"
+        "dQoXvqU34XydPgPQ985XIIuiDkaomRw4yYd/Sh4ZapFcrP++iJ1V+WS6kLcWPHMq\n"
+        "poYwk8mq6GLbPFLEjr+n6HgX5ln15n3i4WAopNH7mEl0glY9L0rxmcN0XOpqw6Ux\n"
+        "ETGEfAwCgYAiOeYwblMkkTIGtVx5NvNsOlfrBYL4GqUP9oQMO5I+xLZLWQIf+7Jp\n"
+        "8t6mwxSBz0RHjNVQ11vZowNjq3587aLy57bVwf2lIm9KSvS6z9HoNbHgQimcBorR\n"
+        "J9l9RUrj7TnsZgiVw66j2r34nHRHRtggiO+qrMtw7MJc0Q7jiuTmzgIVAMXbk0T9\n"
+        "nBfSLWQz/L8RexU2GR4e\n"
+        "-----END DSA PRIVATE KEY-----\n"
+    );
+
+    const QByteArray keyData = keyString.toLatin1();
+
+    OpenSSHKey key;
+    QVERIFY(key.parse(keyData));
+    QVERIFY(!key.encrypted());
+    QCOMPARE(key.cipherName(), QString("none"));
+    QCOMPARE(key.type(), QString("ssh-dss"));
+    QCOMPARE(key.comment(), QString(""));
+    QCOMPARE(key.fingerprint(), QString("SHA256:tbbNuLN1hja8JNASDTlLOZQsbTlJDzJlz/oAGK3sX18"));
+}
+
+void TestOpenSSHKey::testParseRSA()
+{
+    const QString keyString = QString(
+        "-----BEGIN RSA PRIVATE KEY-----\n"
+        "MIIEpAIBAAKCAQEAsCHtJicDPWnvHSIKbnTZaJkIB9vgE0pmLdK580JUqBuonVbB\n"
+        "y1QTy0ZQ7/TtqvLPgwPK88TR46OLO/QGCzo2+XxgJ85uy0xfuyUYRmSuw0drsErN\n"
+        "mH8vU91lSBxsGDp9LtBbgHKoR23vMWZ34IxFRc55XphrIH48ijsMaL6bXBwF/3tD\n"
+        "9T3lm2MpP1huyVNnIY9+GRRWCy4f9LMj/UGu/n4RtwwfpOZBBRwYkq5QkzA9lPm/\n"
+        "VzF3MP1rKTMkvAw+Nfb383mkmc6MRnsa6uh6iDa9aVB7naegM13UJQX/PY1Ks6pO\n"
+        "XDpy/MQ7iCh+HmYNq5dRmARyaNl9xIXJNhz1cQIDAQABAoIBAQCnEUc1LUQxeM5K\n"
+        "wANNCqE+SgoIClPdeHC7fmrLh1ttqe6ib6ybBUFRS31yXs0hnfefunVEDKlaV8K2\n"
+        "N52UAMAsngFHQNRvGh6kEWeZPd9Xc+N98TZbNCjcT+DGKc+Om8wqH5DrodZlCq4c\n"
+        "GaoT4HnE4TjWtZTH2XXrWF9I66PKFWf070R44nvyVcvaZi4pC2YmURRPuGF6K1iK\n"
+        "dH8zM6HHG1UGu2W6hLNn+K01IulG0Lb8eWNaNYMmtQWaxyp7I2IWkkecUs3nCuiR\n"
+        "byFOoomCjdh8r9yZFvwxjGUhgtkALN9GCU0Mwve+s11IB2gevruN+q9/Qejbyfdm\n"
+        "IlgLAeTRAoGBANRcVzW9CYeobCf+U9hKJFEOur8XO+J2mTMaELA0EjWpTJFAeIT7\n"
+        "KeRpCRG4/vOSklxxRF6vP1EACA4Z+5BlN+FTipHHs+bSEgqkPZiiANDH7Zot5Iqv\n"
+        "1q0fRyldNRZNZK7DWp08BPNVWGA/EnEuKJiURxnxBaxNXbUyMCdjxvMvAoGBANRT\n"
+        "utbrqS/bAa/DcHKn3V6DRqBl3TDOfvCNjiKC84a67F2uXgzLIdMktr4d1NyCZVJd\n"
+        "7/zVgWORLIdg1eAi6rYGoOvNV39wwga7CF+m9sBY0wAaKYCELe6L26r4aQHVCX6n\n"
+        "rnIgUv+4o4itmU2iP0r3wlmDC9pDRQP82vfvQPlfAoGASwhleANW/quvq2HdViq8\n"
+        "Mje2HBalfhrRfpDTHK8JUBSFjTzuWG42GxJRtgVbb8x2ElujAKGDCaetMO5VSGu7\n"
+        "Fs5hw6iAFCpdXY0yhl+XUi2R8kwM2EPQ4lKO3jqkq0ClNmqn9a5jQWcCVt9yMLNS\n"
+        "fLbHeI8EpiCf34ngIcrLXNkCgYEAzlcEZuKkC46xB+dNew8pMTUwSKZVm53BfPKD\n"
+        "44QRN6imFbBjU9mAaJnwQbfp6dWKs834cGPolyM4++MeVfB42iZ88ksesgmZdUMD\n"
+        "szkl6O0pOJs0I+HQZVdjRbadDZvD22MHQ3+oST1dJ3FVXz3Cdo9qPuT8esMO6f4r\n"
+        "qfDH2s8CgYAXC/lWWHQ//PGP0pH4oiEXisx1K0X1u0xMGgrChxBRGRiKZUwNMIvJ\n"
+        "TqUu7IKizK19cLHF/NBvxHYHFw+m7puNjn6T1RtRCUjRZT7Dx1VHfVosL9ih5DA8\n"
+        "tpbZA5KGKcvHtB5DDgT0MHwzBZnb4Q//Rhovzn+HXZPsJTTgHHy3NQ==\n"
+        "-----END RSA PRIVATE KEY-----\n"
+    );
+
+    const QByteArray keyData = keyString.toLatin1();
+
+    OpenSSHKey key;
+    QVERIFY(key.parse(keyData));
+    QVERIFY(!key.encrypted());
+    QCOMPARE(key.cipherName(), QString("none"));
+    QCOMPARE(key.type(), QString("ssh-rsa"));
+    QCOMPARE(key.comment(), QString(""));
+    QCOMPARE(key.fingerprint(), QString("SHA256:DYdaZciYNxCejr+/8x+OKYxeTU1D5UsuIFUG4PWRFkk"));
+}
+
 void TestOpenSSHKey::testDecryptAES256CBC()
 {
     const QString keyString = QString(

tests/TestOpenSSHKey.h

@@ -29,6 +29,8 @@ class TestOpenSSHKey : public QObject
 private slots:
     void initTestCase();
     void testParse();
+    void testParseDSA();
+    void testParseRSA();
     void testDecryptAES256CBC();
     void testDecryptAES256CTR();
 };