1 files changed, 270 insertions, 0 deletions

diff --git a/tools/dumpkey/DumpPublicKey.java b/tools/dumpkey/DumpPublicKey.java
new file mode 100644
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+++ b/tools/dumpkey/DumpPublicKey.java
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+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.dumpkey;
+
+import org.bouncycastle.jce.provider.BouncyCastleProvider;
+
+import java.io.FileInputStream;
+import java.math.BigInteger;
+import java.security.cert.CertificateFactory;
+import java.security.cert.X509Certificate;
+import java.security.KeyStore;
+import java.security.Key;
+import java.security.PublicKey;
+import java.security.Security;
+import java.security.interfaces.ECPublicKey;
+import java.security.interfaces.RSAPublicKey;
+import java.security.spec.ECPoint;
+
+/**
+ * Command line tool to extract RSA public keys from X.509 certificates
+ * and output source code with data initializers for the keys.
+ * @hide
+ */
+class DumpPublicKey {
+    /**
+     * @param key to perform sanity checks on
+     * @return version number of key.  Supported versions are:
+     *     1: 2048-bit RSA key with e=3 and SHA-1 hash
+     *     2: 2048-bit RSA key with e=65537 and SHA-1 hash
+     *     3: 2048-bit RSA key with e=3 and SHA-256 hash
+     *     4: 2048-bit RSA key with e=65537 and SHA-256 hash
+     * @throws Exception if the key has the wrong size or public exponent
+     */
+    static int checkRSA(RSAPublicKey key, boolean useSHA256) throws Exception {
+        BigInteger pubexp = key.getPublicExponent();
+        BigInteger modulus = key.getModulus();
+        int version;
+
+        if (pubexp.equals(BigInteger.valueOf(3))) {
+            version = useSHA256 ? 3 : 1;
+        } else if (pubexp.equals(BigInteger.valueOf(65537))) {
+            version = useSHA256 ? 4 : 2;
+        } else {
+            throw new Exception("Public exponent should be 3 or 65537 but is " +
+                                pubexp.toString(10) + ".");
+        }
+
+        if (modulus.bitLength() != 2048) {
+             throw new Exception("Modulus should be 2048 bits long but is " +
+                        modulus.bitLength() + " bits.");
+        }
+
+        return version;
+    }
+
+    /**
+     * @param key to perform sanity checks on
+     * @return version number of key.  Supported versions are:
+     *     5: 256-bit EC key with curve NIST P-256
+     * @throws Exception if the key has the wrong size or public exponent
+     */
+    static int checkEC(ECPublicKey key) throws Exception {
+        if (key.getParams().getCurve().getField().getFieldSize() != 256) {
+            throw new Exception("Curve must be NIST P-256");
+        }
+
+        return 5;
+    }
+
+    /**
+     * Perform sanity check on public key.
+     */
+    static int check(PublicKey key, boolean useSHA256) throws Exception {
+        if (key instanceof RSAPublicKey) {
+            return checkRSA((RSAPublicKey) key, useSHA256);
+        } else if (key instanceof ECPublicKey) {
+            if (!useSHA256) {
+                throw new Exception("Must use SHA-256 with EC keys!");
+            }
+            return checkEC((ECPublicKey) key);
+        } else {
+            throw new Exception("Unsupported key class: " + key.getClass().getName());
+        }
+    }
+
+    /**
+     * @param key to output
+     * @return a String representing this public key.  If the key is a
+     *    version 1 key, the string will be a C initializer; this is
+     *    not true for newer key versions.
+     */
+    static String printRSA(RSAPublicKey key, boolean useSHA256) throws Exception {
+        int version = check(key, useSHA256);
+
+        BigInteger N = key.getModulus();
+
+        StringBuilder result = new StringBuilder();
+
+        int nwords = N.bitLength() / 32;    // # of 32 bit integers in modulus
+
+        if (version > 1) {
+            result.append("v");
+            result.append(Integer.toString(version));
+            result.append(" ");
+        }
+
+        result.append("{");
+        result.append(nwords);
+
+        BigInteger B = BigInteger.valueOf(0x100000000L);  // 2^32
+        BigInteger N0inv = B.subtract(N.modInverse(B));   // -1 / N[0] mod 2^32
+
+        result.append(",0x");
+        result.append(N0inv.toString(16));
+
+        BigInteger R = BigInteger.valueOf(2).pow(N.bitLength());
+        BigInteger RR = R.multiply(R).mod(N);    // 2^4096 mod N
+
+        // Write out modulus as little endian array of integers.
+        result.append(",{");
+        for (int i = 0; i < nwords; ++i) {
+            long n = N.mod(B).longValue();
+            result.append(n);
+
+            if (i != nwords - 1) {
+                result.append(",");
+            }
+
+            N = N.divide(B);
+        }
+        result.append("}");
+
+        // Write R^2 as little endian array of integers.
+        result.append(",{");
+        for (int i = 0; i < nwords; ++i) {
+            long rr = RR.mod(B).longValue();
+            result.append(rr);
+
+            if (i != nwords - 1) {
+                result.append(",");
+            }
+
+            RR = RR.divide(B);
+        }
+        result.append("}");
+
+        result.append("}");
+        return result.toString();
+    }
+
+    /**
+     * @param key to output
+     * @return a String representing this public key.  If the key is a
+     *    version 1 key, the string will be a C initializer; this is
+     *    not true for newer key versions.
+     */
+    static String printEC(ECPublicKey key) throws Exception {
+        int version = checkEC(key);
+
+        StringBuilder result = new StringBuilder();
+
+        result.append("v");
+        result.append(Integer.toString(version));
+        result.append(" ");
+
+        BigInteger X = key.getW().getAffineX();
+        BigInteger Y = key.getW().getAffineY();
+        int nbytes = key.getParams().getCurve().getField().getFieldSize() / 8;    // # of 32 bit integers in X coordinate
+
+        result.append("{");
+        result.append(nbytes);
+
+        BigInteger B = BigInteger.valueOf(0x100L);  // 2^8
+
+        // Write out Y coordinate as array of characters.
+        result.append(",{");
+        for (int i = 0; i < nbytes; ++i) {
+            long n = X.mod(B).longValue();
+            result.append(n);
+
+            if (i != nbytes - 1) {
+                result.append(",");
+            }
+
+            X = X.divide(B);
+        }
+        result.append("}");
+
+        // Write out Y coordinate as array of characters.
+        result.append(",{");
+        for (int i = 0; i < nbytes; ++i) {
+            long n = Y.mod(B).longValue();
+            result.append(n);
+
+            if (i != nbytes - 1) {
+                result.append(",");
+            }
+
+            Y = Y.divide(B);
+        }
+        result.append("}");
+
+        result.append("}");
+        return result.toString();
+    }
+
+    static String print(PublicKey key, boolean useSHA256) throws Exception {
+        if (key instanceof RSAPublicKey) {
+            return printRSA((RSAPublicKey) key, useSHA256);
+        } else if (key instanceof ECPublicKey) {
+            return printEC((ECPublicKey) key);
+        } else {
+            throw new Exception("Unsupported key class: " + key.getClass().getName());
+        }
+    }
+
+    public static void main(String[] args) {
+        if (args.length < 1) {
+            System.err.println("Usage: DumpPublicKey certfile ... > source.c");
+            System.exit(1);
+        }
+        Security.addProvider(new BouncyCastleProvider());
+        try {
+            for (int i = 0; i < args.length; i++) {
+                FileInputStream input = new FileInputStream(args[i]);
+                CertificateFactory cf = CertificateFactory.getInstance("X.509");
+                X509Certificate cert = (X509Certificate) cf.generateCertificate(input);
+
+                boolean useSHA256 = false;
+                String sigAlg = cert.getSigAlgName();
+                if ("SHA1withRSA".equals(sigAlg) || "MD5withRSA".equals(sigAlg)) {
+                    // SignApk has historically accepted "MD5withRSA"
+                    // certificates, but treated them as "SHA1withRSA"
+                    // anyway.  Continue to do so for backwards
+                    // compatibility.
+                  useSHA256 = false;
+                } else if ("SHA256withRSA".equals(sigAlg) || "SHA256withECDSA".equals(sigAlg)) {
+                  useSHA256 = true;
+                } else {
+                  System.err.println(args[i] + ": unsupported signature algorithm \"" +
+                                     sigAlg + "\"");
+                  System.exit(1);
+                }
+
+                PublicKey key = cert.getPublicKey();
+                check(key, useSHA256);
+                System.out.print(print(key, useSHA256));
+                System.out.println(i < args.length - 1 ? "," : "");
+            }
+        } catch (Exception e) {
+            e.printStackTrace();
+            System.exit(1);
+        }
+        System.exit(0);
+    }
+}