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-rw-r--r--org.eclipse.jgit/src/org/eclipse/jgit/util/sha1/SHA1Java.java579
1 files changed, 579 insertions, 0 deletions
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/util/sha1/SHA1Java.java b/org.eclipse.jgit/src/org/eclipse/jgit/util/sha1/SHA1Java.java
new file mode 100644
index 0000000000..213ee97531
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/util/sha1/SHA1Java.java
@@ -0,0 +1,579 @@
+/*
+ * 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
+ */
+class SHA1Java extends SHA1 {
+ private static final Logger LOG = LoggerFactory.getLogger(SHA1Java.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;
+ }
+
+ 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();
+
+ SHA1Java() {
+ 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}
+ */
+ @Override
+ public SHA1 setDetectCollision(boolean detect) {
+ detectCollision = detect;
+ return this;
+ }
+
+ /**
+ * Update the digest computation by adding a byte.
+ *
+ * @param b a byte.
+ */
+ @Override
+ 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.
+ */
+ @Override
+ 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.
+ */
+ @Override
+ 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.
+ */
+ @Override
+ 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.
+ */
+ @Override
+ 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.
+ */
+ @Override
+ 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.
+ */
+ @Override
+ public boolean hasCollision() {
+ return foundCollision;
+ }
+
+ /**
+ * Reset this instance to compute another hash.
+ *
+ * @return {@code this}.
+ */
+ @Override
+ 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);
+ }
+ }
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-28 04:59:40 +0000