| /* |
| * Copyright (C) 2017, Google Inc. and others |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Distribution License v. 1.0 which is available at |
| * https://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| |
| package org.eclipse.jgit.util.sha1; |
| |
| import static java.lang.Integer.lowestOneBit; |
| import static java.lang.Integer.numberOfTrailingZeros; |
| import static java.lang.Integer.rotateLeft; |
| import static java.lang.Integer.rotateRight; |
| |
| import java.text.MessageFormat; |
| import java.util.Arrays; |
| |
| import org.eclipse.jgit.internal.JGitText; |
| import org.eclipse.jgit.lib.MutableObjectId; |
| import org.eclipse.jgit.lib.ObjectId; |
| import org.eclipse.jgit.util.NB; |
| import org.eclipse.jgit.util.SystemReader; |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * Pure Java implementation of SHA-1 from FIPS 180-1 / RFC 3174. |
| * |
| * <p> |
| * See <a href="https://tools.ietf.org/html/rfc3174">RFC 3174</a>. |
| * <p> |
| * Unlike MessageDigest, this implementation includes the algorithm used by |
| * {@code sha1dc} to detect cryptanalytic collision attacks against SHA-1, such |
| * as the one used by <a href="https://shattered.it/">SHAttered</a>. See |
| * <a href="https://github.com/cr-marcstevens/sha1collisiondetection"> |
| * sha1collisiondetection</a> for more information. |
| * <p> |
| * When detectCollision is true (default), this implementation throws |
| * {@link org.eclipse.jgit.util.sha1.Sha1CollisionException} from any digest |
| * method if a potential collision was detected. |
| * |
| * @since 4.7 |
| */ |
| public class SHA1 { |
| private static final Logger LOG = LoggerFactory.getLogger(SHA1.class); |
| private static final boolean DETECT_COLLISIONS; |
| |
| static { |
| SystemReader sr = SystemReader.getInstance(); |
| String v = sr.getProperty("org.eclipse.jgit.util.sha1.detectCollision"); //$NON-NLS-1$ |
| DETECT_COLLISIONS = v != null ? Boolean.parseBoolean(v) : true; |
| } |
| |
| /** |
| * Create a new context to compute a SHA-1 hash of data. |
| * |
| * @return a new context to compute a SHA-1 hash of data. |
| */ |
| public static SHA1 newInstance() { |
| return new SHA1(); |
| } |
| |
| private final State h = new State(); |
| private final int[] w = new int[80]; |
| |
| /** Buffer to accumulate partial blocks to 64 byte alignment. */ |
| private final byte[] buffer = new byte[64]; |
| |
| /** Total number of bytes in the message. */ |
| private long length; |
| |
| private boolean detectCollision = DETECT_COLLISIONS; |
| private boolean foundCollision; |
| |
| private final int[] w2 = new int[80]; |
| private final State state58 = new State(); |
| private final State state65 = new State(); |
| private final State hIn = new State(); |
| private final State hTmp = new State(); |
| |
| private SHA1() { |
| h.init(); |
| } |
| |
| /** |
| * Enable likely collision detection. |
| * <p> |
| * Default is {@code true}. |
| * <p> |
| * May also be set by system property: |
| * {@code -Dorg.eclipse.jgit.util.sha1.detectCollision=true}. |
| * |
| * @param detect |
| * a boolean. |
| * @return {@code this} |
| */ |
| public SHA1 setDetectCollision(boolean detect) { |
| detectCollision = detect; |
| return this; |
| } |
| |
| /** |
| * Update the digest computation by adding a byte. |
| * |
| * @param b a byte. |
| */ |
| public void update(byte b) { |
| int bufferLen = (int) (length & 63); |
| length++; |
| buffer[bufferLen] = b; |
| if (bufferLen == 63) { |
| compress(buffer, 0); |
| } |
| } |
| |
| /** |
| * Update the digest computation by adding bytes to the message. |
| * |
| * @param in |
| * input array of bytes. |
| */ |
| public void update(byte[] in) { |
| update(in, 0, in.length); |
| } |
| |
| /** |
| * Update the digest computation by adding bytes to the message. |
| * |
| * @param in |
| * input array of bytes. |
| * @param p |
| * offset to start at from {@code in}. |
| * @param len |
| * number of bytes to hash. |
| */ |
| public void update(byte[] in, int p, int len) { |
| // SHA-1 compress can only process whole 64 byte blocks. |
| // Hold partial updates in buffer, whose length is the low bits. |
| int bufferLen = (int) (length & 63); |
| length += len; |
| |
| if (bufferLen > 0) { |
| int n = Math.min(64 - bufferLen, len); |
| System.arraycopy(in, p, buffer, bufferLen, n); |
| p += n; |
| len -= n; |
| if (bufferLen + n < 64) { |
| return; |
| } |
| compress(buffer, 0); |
| } |
| while (len >= 64) { |
| compress(in, p); |
| p += 64; |
| len -= 64; |
| } |
| if (len > 0) { |
| System.arraycopy(in, p, buffer, 0, len); |
| } |
| } |
| |
| private void compress(byte[] block, int p) { |
| initBlock(block, p); |
| int ubcDvMask = detectCollision ? UbcCheck.check(w) : 0; |
| compress(); |
| |
| while (ubcDvMask != 0) { |
| int b = numberOfTrailingZeros(lowestOneBit(ubcDvMask)); |
| UbcCheck.DvInfo dv = UbcCheck.DV[b]; |
| for (int i = 0; i < 80; i++) { |
| w2[i] = w[i] ^ dv.dm[i]; |
| } |
| recompress(dv.testt); |
| if (eq(hTmp, h)) { |
| foundCollision = true; |
| break; |
| } |
| ubcDvMask &= ~(1 << b); |
| } |
| } |
| |
| private void initBlock(byte[] block, int p) { |
| for (int t = 0; t < 16; t++) { |
| w[t] = NB.decodeInt32(block, p + (t << 2)); |
| } |
| |
| // RFC 3174 6.1.b, extend state vector to 80 words. |
| for (int t = 16; t < 80; t++) { |
| int x = w[t - 3] ^ w[t - 8] ^ w[t - 14] ^ w[t - 16]; |
| w[t] = rotateLeft(x, 1); // S^1(...) |
| } |
| } |
| |
| private void compress() { |
| // Method 1 from RFC 3174 section 6.1. |
| // Method 2 (circular queue of 16 words) is slower. |
| int a = h.a, b = h.b, c = h.c, d = h.d, e = h.e; |
| |
| // @formatter:off |
| e += s1(a, b, c, d,w[ 0]); b = rotateLeft( b, 30); |
| d += s1(e, a, b, c,w[ 1]); a = rotateLeft( a, 30); |
| c += s1(d, e, a, b,w[ 2]); e = rotateLeft( e, 30); |
| b += s1(c, d, e, a,w[ 3]); d = rotateLeft( d, 30); |
| a += s1(b, c, d, e,w[ 4]); c = rotateLeft( c, 30); |
| e += s1(a, b, c, d,w[ 5]); b = rotateLeft( b, 30); |
| d += s1(e, a, b, c,w[ 6]); a = rotateLeft( a, 30); |
| c += s1(d, e, a, b,w[ 7]); e = rotateLeft( e, 30); |
| b += s1(c, d, e, a,w[ 8]); d = rotateLeft( d, 30); |
| a += s1(b, c, d, e,w[ 9]); c = rotateLeft( c, 30); |
| e += s1(a, b, c, d,w[ 10]); b = rotateLeft( b, 30); |
| d += s1(e, a, b, c,w[ 11]); a = rotateLeft( a, 30); |
| c += s1(d, e, a, b,w[ 12]); e = rotateLeft( e, 30); |
| b += s1(c, d, e, a,w[ 13]); d = rotateLeft( d, 30); |
| a += s1(b, c, d, e,w[ 14]); c = rotateLeft( c, 30); |
| e += s1(a, b, c, d,w[ 15]); b = rotateLeft( b, 30); |
| d += s1(e, a, b, c,w[ 16]); a = rotateLeft( a, 30); |
| c += s1(d, e, a, b,w[ 17]); e = rotateLeft( e, 30); |
| b += s1(c, d, e, a,w[ 18]); d = rotateLeft( d, 30); |
| a += s1(b, c, d, e,w[ 19]); c = rotateLeft( c, 30); |
| |
| e += s2(a, b, c, d,w[ 20]); b = rotateLeft( b, 30); |
| d += s2(e, a, b, c,w[ 21]); a = rotateLeft( a, 30); |
| c += s2(d, e, a, b,w[ 22]); e = rotateLeft( e, 30); |
| b += s2(c, d, e, a,w[ 23]); d = rotateLeft( d, 30); |
| a += s2(b, c, d, e,w[ 24]); c = rotateLeft( c, 30); |
| e += s2(a, b, c, d,w[ 25]); b = rotateLeft( b, 30); |
| d += s2(e, a, b, c,w[ 26]); a = rotateLeft( a, 30); |
| c += s2(d, e, a, b,w[ 27]); e = rotateLeft( e, 30); |
| b += s2(c, d, e, a,w[ 28]); d = rotateLeft( d, 30); |
| a += s2(b, c, d, e,w[ 29]); c = rotateLeft( c, 30); |
| e += s2(a, b, c, d,w[ 30]); b = rotateLeft( b, 30); |
| d += s2(e, a, b, c,w[ 31]); a = rotateLeft( a, 30); |
| c += s2(d, e, a, b,w[ 32]); e = rotateLeft( e, 30); |
| b += s2(c, d, e, a,w[ 33]); d = rotateLeft( d, 30); |
| a += s2(b, c, d, e,w[ 34]); c = rotateLeft( c, 30); |
| e += s2(a, b, c, d,w[ 35]); b = rotateLeft( b, 30); |
| d += s2(e, a, b, c,w[ 36]); a = rotateLeft( a, 30); |
| c += s2(d, e, a, b,w[ 37]); e = rotateLeft( e, 30); |
| b += s2(c, d, e, a,w[ 38]); d = rotateLeft( d, 30); |
| a += s2(b, c, d, e,w[ 39]); c = rotateLeft( c, 30); |
| |
| e += s3(a, b, c, d,w[ 40]); b = rotateLeft( b, 30); |
| d += s3(e, a, b, c,w[ 41]); a = rotateLeft( a, 30); |
| c += s3(d, e, a, b,w[ 42]); e = rotateLeft( e, 30); |
| b += s3(c, d, e, a,w[ 43]); d = rotateLeft( d, 30); |
| a += s3(b, c, d, e,w[ 44]); c = rotateLeft( c, 30); |
| e += s3(a, b, c, d,w[ 45]); b = rotateLeft( b, 30); |
| d += s3(e, a, b, c,w[ 46]); a = rotateLeft( a, 30); |
| c += s3(d, e, a, b,w[ 47]); e = rotateLeft( e, 30); |
| b += s3(c, d, e, a,w[ 48]); d = rotateLeft( d, 30); |
| a += s3(b, c, d, e,w[ 49]); c = rotateLeft( c, 30); |
| e += s3(a, b, c, d,w[ 50]); b = rotateLeft( b, 30); |
| d += s3(e, a, b, c,w[ 51]); a = rotateLeft( a, 30); |
| c += s3(d, e, a, b,w[ 52]); e = rotateLeft( e, 30); |
| b += s3(c, d, e, a,w[ 53]); d = rotateLeft( d, 30); |
| a += s3(b, c, d, e,w[ 54]); c = rotateLeft( c, 30); |
| e += s3(a, b, c, d,w[ 55]); b = rotateLeft( b, 30); |
| d += s3(e, a, b, c,w[ 56]); a = rotateLeft( a, 30); |
| c += s3(d, e, a, b,w[ 57]); e = rotateLeft( e, 30); |
| state58.save(a, b, c, d, e); |
| b += s3(c, d, e, a,w[ 58]); d = rotateLeft( d, 30); |
| a += s3(b, c, d, e,w[ 59]); c = rotateLeft( c, 30); |
| |
| e += s4(a, b, c, d,w[ 60]); b = rotateLeft( b, 30); |
| d += s4(e, a, b, c,w[ 61]); a = rotateLeft( a, 30); |
| c += s4(d, e, a, b,w[ 62]); e = rotateLeft( e, 30); |
| b += s4(c, d, e, a,w[ 63]); d = rotateLeft( d, 30); |
| a += s4(b, c, d, e,w[ 64]); c = rotateLeft( c, 30); |
| state65.save(a, b, c, d, e); |
| e += s4(a, b, c, d,w[ 65]); b = rotateLeft( b, 30); |
| d += s4(e, a, b, c,w[ 66]); a = rotateLeft( a, 30); |
| c += s4(d, e, a, b,w[ 67]); e = rotateLeft( e, 30); |
| b += s4(c, d, e, a,w[ 68]); d = rotateLeft( d, 30); |
| a += s4(b, c, d, e,w[ 69]); c = rotateLeft( c, 30); |
| e += s4(a, b, c, d,w[ 70]); b = rotateLeft( b, 30); |
| d += s4(e, a, b, c,w[ 71]); a = rotateLeft( a, 30); |
| c += s4(d, e, a, b,w[ 72]); e = rotateLeft( e, 30); |
| b += s4(c, d, e, a,w[ 73]); d = rotateLeft( d, 30); |
| a += s4(b, c, d, e,w[ 74]); c = rotateLeft( c, 30); |
| e += s4(a, b, c, d,w[ 75]); b = rotateLeft( b, 30); |
| d += s4(e, a, b, c,w[ 76]); a = rotateLeft( a, 30); |
| c += s4(d, e, a, b,w[ 77]); e = rotateLeft( e, 30); |
| b += s4(c, d, e, a,w[ 78]); d = rotateLeft( d, 30); |
| a += s4(b, c, d, e,w[ 79]); c = rotateLeft( c, 30); |
| |
| // @formatter:on |
| h.save(h.a + a, h.b + b, h.c + c, h.d + d, h.e + e); |
| } |
| |
| private void recompress(int t) { |
| State s; |
| switch (t) { |
| case 58: |
| s = state58; |
| break; |
| case 65: |
| s = state65; |
| break; |
| default: |
| throw new IllegalStateException(); |
| } |
| int a = s.a, b = s.b, c = s.c, d = s.d, e = s.e; |
| |
| // @formatter:off |
| if (t == 65) { |
| { c = rotateRight( c, 30); a -= s4(b, c, d, e,w2[ 64]);} |
| { d = rotateRight( d, 30); b -= s4(c, d, e, a,w2[ 63]);} |
| { e = rotateRight( e, 30); c -= s4(d, e, a, b,w2[ 62]);} |
| { a = rotateRight( a, 30); d -= s4(e, a, b, c,w2[ 61]);} |
| { b = rotateRight( b, 30); e -= s4(a, b, c, d,w2[ 60]);} |
| |
| { c = rotateRight( c, 30); a -= s3(b, c, d, e,w2[ 59]);} |
| { d = rotateRight( d, 30); b -= s3(c, d, e, a,w2[ 58]);} |
| } |
| { e = rotateRight( e, 30); c -= s3(d, e, a, b,w2[ 57]);} |
| { a = rotateRight( a, 30); d -= s3(e, a, b, c,w2[ 56]);} |
| { b = rotateRight( b, 30); e -= s3(a, b, c, d,w2[ 55]);} |
| { c = rotateRight( c, 30); a -= s3(b, c, d, e,w2[ 54]);} |
| { d = rotateRight( d, 30); b -= s3(c, d, e, a,w2[ 53]);} |
| { e = rotateRight( e, 30); c -= s3(d, e, a, b,w2[ 52]);} |
| { a = rotateRight( a, 30); d -= s3(e, a, b, c,w2[ 51]);} |
| { b = rotateRight( b, 30); e -= s3(a, b, c, d,w2[ 50]);} |
| { c = rotateRight( c, 30); a -= s3(b, c, d, e,w2[ 49]);} |
| { d = rotateRight( d, 30); b -= s3(c, d, e, a,w2[ 48]);} |
| { e = rotateRight( e, 30); c -= s3(d, e, a, b,w2[ 47]);} |
| { a = rotateRight( a, 30); d -= s3(e, a, b, c,w2[ 46]);} |
| { b = rotateRight( b, 30); e -= s3(a, b, c, d,w2[ 45]);} |
| { c = rotateRight( c, 30); a -= s3(b, c, d, e,w2[ 44]);} |
| { d = rotateRight( d, 30); b -= s3(c, d, e, a,w2[ 43]);} |
| { e = rotateRight( e, 30); c -= s3(d, e, a, b,w2[ 42]);} |
| { a = rotateRight( a, 30); d -= s3(e, a, b, c,w2[ 41]);} |
| { b = rotateRight( b, 30); e -= s3(a, b, c, d,w2[ 40]);} |
| |
| { c = rotateRight( c, 30); a -= s2(b, c, d, e,w2[ 39]);} |
| { d = rotateRight( d, 30); b -= s2(c, d, e, a,w2[ 38]);} |
| { e = rotateRight( e, 30); c -= s2(d, e, a, b,w2[ 37]);} |
| { a = rotateRight( a, 30); d -= s2(e, a, b, c,w2[ 36]);} |
| { b = rotateRight( b, 30); e -= s2(a, b, c, d,w2[ 35]);} |
| { c = rotateRight( c, 30); a -= s2(b, c, d, e,w2[ 34]);} |
| { d = rotateRight( d, 30); b -= s2(c, d, e, a,w2[ 33]);} |
| { e = rotateRight( e, 30); c -= s2(d, e, a, b,w2[ 32]);} |
| { a = rotateRight( a, 30); d -= s2(e, a, b, c,w2[ 31]);} |
| { b = rotateRight( b, 30); e -= s2(a, b, c, d,w2[ 30]);} |
| { c = rotateRight( c, 30); a -= s2(b, c, d, e,w2[ 29]);} |
| { d = rotateRight( d, 30); b -= s2(c, d, e, a,w2[ 28]);} |
| { e = rotateRight( e, 30); c -= s2(d, e, a, b,w2[ 27]);} |
| { a = rotateRight( a, 30); d -= s2(e, a, b, c,w2[ 26]);} |
| { b = rotateRight( b, 30); e -= s2(a, b, c, d,w2[ 25]);} |
| { c = rotateRight( c, 30); a -= s2(b, c, d, e,w2[ 24]);} |
| { d = rotateRight( d, 30); b -= s2(c, d, e, a,w2[ 23]);} |
| { e = rotateRight( e, 30); c -= s2(d, e, a, b,w2[ 22]);} |
| { a = rotateRight( a, 30); d -= s2(e, a, b, c,w2[ 21]);} |
| { b = rotateRight( b, 30); e -= s2(a, b, c, d,w2[ 20]);} |
| |
| { c = rotateRight( c, 30); a -= s1(b, c, d, e,w2[ 19]);} |
| { d = rotateRight( d, 30); b -= s1(c, d, e, a,w2[ 18]);} |
| { e = rotateRight( e, 30); c -= s1(d, e, a, b,w2[ 17]);} |
| { a = rotateRight( a, 30); d -= s1(e, a, b, c,w2[ 16]);} |
| { b = rotateRight( b, 30); e -= s1(a, b, c, d,w2[ 15]);} |
| { c = rotateRight( c, 30); a -= s1(b, c, d, e,w2[ 14]);} |
| { d = rotateRight( d, 30); b -= s1(c, d, e, a,w2[ 13]);} |
| { e = rotateRight( e, 30); c -= s1(d, e, a, b,w2[ 12]);} |
| { a = rotateRight( a, 30); d -= s1(e, a, b, c,w2[ 11]);} |
| { b = rotateRight( b, 30); e -= s1(a, b, c, d,w2[ 10]);} |
| { c = rotateRight( c, 30); a -= s1(b, c, d, e,w2[ 9]);} |
| { d = rotateRight( d, 30); b -= s1(c, d, e, a,w2[ 8]);} |
| { e = rotateRight( e, 30); c -= s1(d, e, a, b,w2[ 7]);} |
| { a = rotateRight( a, 30); d -= s1(e, a, b, c,w2[ 6]);} |
| { b = rotateRight( b, 30); e -= s1(a, b, c, d,w2[ 5]);} |
| { c = rotateRight( c, 30); a -= s1(b, c, d, e,w2[ 4]);} |
| { d = rotateRight( d, 30); b -= s1(c, d, e, a,w2[ 3]);} |
| { e = rotateRight( e, 30); c -= s1(d, e, a, b,w2[ 2]);} |
| { a = rotateRight( a, 30); d -= s1(e, a, b, c,w2[ 1]);} |
| { b = rotateRight( b, 30); e -= s1(a, b, c, d,w2[ 0]);} |
| |
| hIn.save(a, b, c, d, e); |
| a = s.a; b = s.b; c = s.c; d = s.d; e = s.e; |
| |
| if (t == 58) { |
| { b += s3(c, d, e, a,w2[ 58]); d = rotateLeft( d, 30);} |
| { a += s3(b, c, d, e,w2[ 59]); c = rotateLeft( c, 30);} |
| |
| { e += s4(a, b, c, d,w2[ 60]); b = rotateLeft( b, 30);} |
| { d += s4(e, a, b, c,w2[ 61]); a = rotateLeft( a, 30);} |
| { c += s4(d, e, a, b,w2[ 62]); e = rotateLeft( e, 30);} |
| { b += s4(c, d, e, a,w2[ 63]); d = rotateLeft( d, 30);} |
| { a += s4(b, c, d, e,w2[ 64]); c = rotateLeft( c, 30);} |
| } |
| { e += s4(a, b, c, d,w2[ 65]); b = rotateLeft( b, 30);} |
| { d += s4(e, a, b, c,w2[ 66]); a = rotateLeft( a, 30);} |
| { c += s4(d, e, a, b,w2[ 67]); e = rotateLeft( e, 30);} |
| { b += s4(c, d, e, a,w2[ 68]); d = rotateLeft( d, 30);} |
| { a += s4(b, c, d, e,w2[ 69]); c = rotateLeft( c, 30);} |
| { e += s4(a, b, c, d,w2[ 70]); b = rotateLeft( b, 30);} |
| { d += s4(e, a, b, c,w2[ 71]); a = rotateLeft( a, 30);} |
| { c += s4(d, e, a, b,w2[ 72]); e = rotateLeft( e, 30);} |
| { b += s4(c, d, e, a,w2[ 73]); d = rotateLeft( d, 30);} |
| { a += s4(b, c, d, e,w2[ 74]); c = rotateLeft( c, 30);} |
| { e += s4(a, b, c, d,w2[ 75]); b = rotateLeft( b, 30);} |
| { d += s4(e, a, b, c,w2[ 76]); a = rotateLeft( a, 30);} |
| { c += s4(d, e, a, b,w2[ 77]); e = rotateLeft( e, 30);} |
| { b += s4(c, d, e, a,w2[ 78]); d = rotateLeft( d, 30);} |
| { a += s4(b, c, d, e,w2[ 79]); c = rotateLeft( c, 30);} |
| |
| // @formatter:on |
| hTmp.save(hIn.a + a, hIn.b + b, hIn.c + c, hIn.d + d, hIn.e + e); |
| } |
| |
| private static int s1(int a, int b, int c, int d, int w_t) { |
| return rotateLeft(a, 5) |
| // f: 0 <= t <= 19 |
| + ((b & c) | ((~b) & d)) |
| + 0x5A827999 + w_t; |
| } |
| |
| private static int s2(int a, int b, int c, int d, int w_t) { |
| return rotateLeft(a, 5) |
| // f: 20 <= t <= 39 |
| + (b ^ c ^ d) |
| + 0x6ED9EBA1 + w_t; |
| } |
| |
| private static int s3(int a, int b, int c, int d, int w_t) { |
| return rotateLeft(a, 5) |
| // f: 40 <= t <= 59 |
| + ((b & c) | (b & d) | (c & d)) |
| + 0x8F1BBCDC + w_t; |
| } |
| |
| private static int s4(int a, int b, int c, int d, int w_t) { |
| return rotateLeft(a, 5) |
| // f: 60 <= t <= 79 |
| + (b ^ c ^ d) |
| + 0xCA62C1D6 + w_t; |
| } |
| |
| private static boolean eq(State q, State r) { |
| return q.a == r.a |
| && q.b == r.b |
| && q.c == r.c |
| && q.d == r.d |
| && q.e == r.e; |
| } |
| |
| private void finish() { |
| int bufferLen = (int) (length & 63); |
| if (bufferLen > 55) { |
| // Last block is too small; pad, compress, pad another block. |
| buffer[bufferLen++] = (byte) 0x80; |
| Arrays.fill(buffer, bufferLen, 64, (byte) 0); |
| compress(buffer, 0); |
| Arrays.fill(buffer, 0, 56, (byte) 0); |
| } else { |
| // Last block can hold padding and length. |
| buffer[bufferLen++] = (byte) 0x80; |
| Arrays.fill(buffer, bufferLen, 56, (byte) 0); |
| } |
| |
| // SHA-1 appends the length of the message in bits after the |
| // padding block (above). Here length is in bytes. Multiply by |
| // 8 by shifting by 3 as part of storing the 64 bit byte length |
| // into the two words expected in the trailer. |
| NB.encodeInt32(buffer, 56, (int) (length >>> (32 - 3))); |
| NB.encodeInt32(buffer, 60, (int) (length << 3)); |
| compress(buffer, 0); |
| |
| if (foundCollision) { |
| ObjectId id = h.toObjectId(); |
| LOG.warn(MessageFormat.format(JGitText.get().sha1CollisionDetected, |
| id.name())); |
| throw new Sha1CollisionException(id); |
| } |
| } |
| |
| /** |
| * Finish the digest and return the resulting hash. |
| * <p> |
| * Once {@code digest()} is called, this instance should be discarded. |
| * |
| * @return the bytes for the resulting hash. |
| * @throws org.eclipse.jgit.util.sha1.Sha1CollisionException |
| * if a collision was detected and safeHash is false. |
| */ |
| public byte[] digest() throws Sha1CollisionException { |
| finish(); |
| |
| byte[] b = new byte[20]; |
| NB.encodeInt32(b, 0, h.a); |
| NB.encodeInt32(b, 4, h.b); |
| NB.encodeInt32(b, 8, h.c); |
| NB.encodeInt32(b, 12, h.d); |
| NB.encodeInt32(b, 16, h.e); |
| return b; |
| } |
| |
| /** |
| * Finish the digest and return the resulting hash. |
| * <p> |
| * Once {@code digest()} is called, this instance should be discarded. |
| * |
| * @return the ObjectId for the resulting hash. |
| * @throws org.eclipse.jgit.util.sha1.Sha1CollisionException |
| * if a collision was detected and safeHash is false. |
| */ |
| public ObjectId toObjectId() throws Sha1CollisionException { |
| finish(); |
| return h.toObjectId(); |
| } |
| |
| /** |
| * Finish the digest and return the resulting hash. |
| * <p> |
| * Once {@code digest()} is called, this instance should be discarded. |
| * |
| * @param id |
| * destination to copy the digest to. |
| * @throws org.eclipse.jgit.util.sha1.Sha1CollisionException |
| * if a collision was detected and safeHash is false. |
| */ |
| public void digest(MutableObjectId id) throws Sha1CollisionException { |
| finish(); |
| id.set(h.a, h.b, h.c, h.d, h.e); |
| } |
| |
| /** |
| * Check if a collision was detected. |
| * |
| * <p> |
| * This method only returns an accurate result after the digest was obtained |
| * through {@link #digest()}, {@link #digest(MutableObjectId)} or |
| * {@link #toObjectId()}, as the hashing function must finish processing to |
| * know the final state. |
| * |
| * @return {@code true} if a likely collision was detected. |
| */ |
| public boolean hasCollision() { |
| return foundCollision; |
| } |
| |
| /** |
| * Reset this instance to compute another hash. |
| * |
| * @return {@code this}. |
| */ |
| public SHA1 reset() { |
| h.init(); |
| length = 0; |
| foundCollision = false; |
| return this; |
| } |
| |
| private static final class State { |
| int a; |
| int b; |
| int c; |
| int d; |
| int e; |
| |
| final void init() { |
| // Magic initialization constants defined by FIPS180. |
| save(0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0); |
| } |
| |
| final void save(int a1, int b1, int c1, int d1, int e1) { |
| a = a1; |
| b = b1; |
| c = c1; |
| d = d1; |
| e = e1; |
| } |
| |
| ObjectId toObjectId() { |
| return new ObjectId(a, b, c, d, e); |
| } |
| } |
| } |