Use public domain MD5 implementation in vespalib

Add basic test vectors to ensure implementation is conformant.

4 files changed, 290 insertions, 276 deletions

diff --git a/vespalib/CMakeLists.txt b/vespalib/CMakeLists.txt
index b6f8775b64b..9e11562c0b0 100644
--- a/vespalib/CMakeLists.txt
+++ b/vespalib/CMakeLists.txt
@@ -99,6 +99,7 @@ vespa_define_module(
     src/tests/tutorial/threads
     src/tests/util/generationhandler
     src/tests/util/generationhandler_stress
+    src/tests/util/md5
     src/tests/valgrind
     src/tests/websocket
     src/tests/zcurve
diff --git a/vespalib/src/tests/util/md5/CMakeLists.txt b/vespalib/src/tests/util/md5/CMakeLists.txt
new file mode 100644
index 00000000000..7c3d1874275
--- /dev/null
+++ b/vespalib/src/tests/util/md5/CMakeLists.txt
@@ -0,0 +1,8 @@
+# Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+vespa_add_executable(vespalib_md5_test_app TEST
+    SOURCES
+    md5_test.cpp
+    DEPENDS
+    vespalib
+)
+vespa_add_test(NAME vespalib_md5_test_app COMMAND vespalib_md5_test_app)
diff --git a/vespalib/src/tests/util/md5/md5_test.cpp b/vespalib/src/tests/util/md5/md5_test.cpp
new file mode 100644
index 00000000000..6061f138566
--- /dev/null
+++ b/vespalib/src/tests/util/md5/md5_test.cpp
@@ -0,0 +1,38 @@
+// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+#include <vespa/vespalib/testkit/test_kit.h>
+#include <vespa/vespalib/util/md5.h>
+#include <vespa/vespalib/stllike/string.h>
+#include <vespa/vespalib/stllike/asciistream.h>
+
+namespace vespalib {
+
+string md5_hash_of(stringref buffer) {
+    unsigned char hash_out[16]; // Always 128 bits.
+    fastc_md5sum(buffer.data(), buffer.size(), hash_out);
+    asciistream os;
+    for (int i = 0; i < 16; ++i) {
+        os << hex << setw(2) << setfill('0') << static_cast<unsigned int>(hash_out[i]);
+    }
+    return os.str();
+}
+
+// https://www.nist.gov/itl/ssd/software-quality-group/nsrl-test-data
+// We only include the informal test vectors here.
+TEST("MD5 output matches NIST test vectors") {
+    EXPECT_EQUAL("900150983cd24fb0d6963f7d28e17f72", md5_hash_of("abc"));
+    EXPECT_EQUAL("8215ef0796a20bcaaae116d3876c664a",
+                 md5_hash_of("abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq"));
+    EXPECT_EQUAL("7707d6ae4e027c70eea2a935c2296f21", md5_hash_of(string(1'000'000, 'a')));
+}
+
+// https://en.wikipedia.org/wiki/MD5#MD5_hashes
+TEST("MD5 output matches Wikipedia test vectors") {
+    EXPECT_EQUAL("d41d8cd98f00b204e9800998ecf8427e", md5_hash_of(""));
+    EXPECT_EQUAL("9e107d9d372bb6826bd81d3542a419d6", md5_hash_of("The quick brown fox jumps over the lazy dog"));
+    EXPECT_EQUAL("e4d909c290d0fb1ca068ffaddf22cbd0", md5_hash_of("The quick brown fox jumps over the lazy dog."));
+}
+
+}
+
+TEST_MAIN() { TEST_RUN_ALL(); }
+
diff --git a/vespalib/src/vespa/vespalib/util/md5.c b/vespalib/src/vespa/vespalib/util/md5.c
index 7c23e84d271..35319ac7e59 100644
--- a/vespalib/src/vespa/vespalib/util/md5.c
+++ b/vespalib/src/vespa/vespalib/util/md5.c
@@ -1,323 +1,290 @@
 // Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 /*
+ * The above copyright notice applies to changes made to code derived from
+ * (original license follows):
  *
- * Generic hash functions to ensure the same hash values are used everywhere.
- */
-
-/*
- * The following copyright notice applies to the code between the
- * "--- START OF MD5 CODE ---" and "--- END OF MD5 CODE ---" markers:
+ * This is an OpenSSL-compatible implementation of the RSA Data Security, Inc.
+ * MD5 Message-Digest Algorithm (RFC 1321).
  *
- *  MD5C.C - RSA Data Security, Inc., MD5 message-digest algorithm
+ * Homepage:
+ * http://openwall.info/wiki/people/solar/software/public-domain-source-code/md5
  *
- * Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
- * rights reserved.
+ * Author:
+ * Alexander Peslyak, better known as Solar Designer <solar at openwall.com>
  *
- * License to copy and use this software is granted provided that it
- * is identified as the "RSA Data Security, Inc. MD5 Message-Digest
- * Algorithm" in all material mentioning or referencing this software
- * or this function.
+ * This software was written by Alexander Peslyak in 2001.  No copyright is
+ * claimed, and the software is hereby placed in the public domain.
+ * In case this attempt to disclaim copyright and place the software in the
+ * public domain is deemed null and void, then the software is
+ * Copyright (c) 2001 Alexander Peslyak and it is hereby released to the
+ * general public under the following terms:
  *
- * License is also granted to make and use derivative works provided
- * that such works are identified as "derived from the RSA Data
- * Security, Inc. MD5 Message-Digest Algorithm" in all material
- * mentioning or referencing the derived work.
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted.
  *
- * RSA Data Security, Inc. makes no representations concerning either
- * the merchantability of this software or the suitability of this
- * software for any particular purpose. It is provided "as is"
- * without express or implied warranty of any kind.
+ * There's ABSOLUTELY NO WARRANTY, express or implied.
  *
- * These notices must be retained in any copies of any part of this
- * documentation and/or software.
+ * (This is a heavily cut-down "BSD license".)
  *
+ * This differs from Colin Plumb's older public domain implementation in that
+ * no exactly 32-bit integer data type is required (any 32-bit or wider
+ * unsigned integer data type will do), there's no compile-time endianness
+ * configuration, and the function prototypes match OpenSSL's.  No code from
+ * Colin Plumb's implementation has been reused; this comment merely compares
+ * the properties of the two independent implementations.
+ *
+ * The primary goals of this implementation are portability and ease of use.
+ * It is meant to be fast, but not as fast as possible.  Some known
+ * optimizations are not included to reduce source code size and avoid
+ * compile-time configuration.
  */
 
-#include "md5.h"
+// Vespalib integration notice: we use static linkage on the digest processing
+// functions, as their signatures intentionally alias those of OpenSSL. Once we
+// start linking with OpenSSL itself, consider using its digest functions instead.
+
 #include <string.h>
-#include <inttypes.h>
-
-/* --- START OF MD5 CODE --- */
-
-#define S11 7
-#define S12 12
-#define S13 17
-#define S14 22
-#define S21 5
-#define S22 9
-#define S23 14
-#define S24 20
-#define S31 4
-#define S32 11
-#define S33 16
-#define S34 23
-#define S41 6
-#define S42 10
-#define S43 15
-#define S44 21
-
-/* MD5 context. */
-typedef struct
-{
-  uint32_t state[4];                                   /* state (ABCD) */
-  uint32_t count[2];        /* number of bits, modulo 2^64 (lsb first) */
-  unsigned char buffer[64];                         /* input buffer */
-} MD5_CTX;
+#include "md5.h"
 
-static void MD5Init (MD5_CTX *);
-static void MD5Update (MD5_CTX *, const unsigned char *, uint32_t);
-static void MD5Final (unsigned char [16], MD5_CTX *);
-static void MD5Transform (uint32_t [4], const unsigned char [64]);
-static void Encode (unsigned char *, uint32_t *, uint32_t);
-static void Decode (uint32_t *, const unsigned char *, uint32_t);
+/* Any 32-bit or wider unsigned integer data type will do */
+typedef unsigned int MD5_u32plus;
 
-static unsigned char PADDING[64] = {
-	0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
-	0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0
-};
+typedef struct {
+    MD5_u32plus lo, hi;
+    MD5_u32plus a, b, c, d;
+    unsigned char buffer[64];
+    MD5_u32plus block[16];
+} MD5_CTX;
 
-/* F, G, H and I are basic MD5 functions.
+/*
+ * The basic MD5 functions.
+ *
+ * F and G are optimized compared to their RFC 1321 definitions for
+ * architectures that lack an AND-NOT instruction, just like in Colin Plumb's
+ * implementation.
  */
-#define F(x, y, z) (((x) & (y)) | ((~x) & (z)))
-#define G(x, y, z) (((x) & (z)) | ((y) & (~z)))
-#define H(x, y, z) ((x) ^ (y) ^ (z))
-#define I(x, y, z) ((y) ^ ((x) | (~z)))
+#define F(x, y, z)  ((z) ^ ((x) & ((y) ^ (z))))
+#define G(x, y, z)  ((y) ^ ((z) & ((x) ^ (y))))
+#define H(x, y, z)  (((x) ^ (y)) ^ (z))
+#define H2(x, y, z) ((x) ^ ((y) ^ (z)))
+#define I(x, y, z)  ((y) ^ ((x) | ~(z)))
 
-/* ROTATE_LEFT rotates x left n bits.
+/*
+ * The MD5 transformation for all four rounds.
  */
-#define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32-(n))))
+#define STEP(f, a, b, c, d, x, t, s) \
+    (a) += f((b), (c), (d)) + (x) + (t); \
+    (a) = (((a) << (s)) | (((a) & 0xffffffff) >> (32 - (s)))); \
+    (a) += (b);
 
-/* FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
-Rotation is separate from addition to prevent recomputation.
+/*
+ * SET reads 4 input bytes in little-endian byte order and stores them in a
+ * properly aligned word in host byte order.
  */
-#define FF(a, b, c, d, x, s, ac) { \
-    (a) += F ((b), (c), (d)) + (x) + (uint32_t)(ac); \
-    (a) = ROTATE_LEFT ((a), (s)); \
-    (a) += (b); \
-}
-#define GG(a, b, c, d, x, s, ac) { \
-    (a) += G ((b), (c), (d)) + (x) + (uint32_t)(ac); \
-    (a) = ROTATE_LEFT ((a), (s)); \
-    (a) += (b); \
-}
-#define HH(a, b, c, d, x, s, ac) { \
-    (a) += H ((b), (c), (d)) + (x) + (uint32_t)(ac); \
-    (a) = ROTATE_LEFT ((a), (s)); \
-    (a) += (b); \
-}
-#define II(a, b, c, d, x, s, ac) { \
-    (a) += I ((b), (c), (d)) + (x) + (uint32_t)(ac); \
-    (a) = ROTATE_LEFT ((a), (s)); \
-    (a) += (b); \
-}
+#define SET(n) \
+    (ctx->block[(n)] = \
+    (MD5_u32plus)ptr[(n) * 4] | \
+    ((MD5_u32plus)ptr[(n) * 4 + 1] << 8) | \
+    ((MD5_u32plus)ptr[(n) * 4 + 2] << 16) | \
+    ((MD5_u32plus)ptr[(n) * 4 + 3] << 24))
+#define GET(n) \
+    (ctx->block[(n)])
 
-/* MD5 initialization. Begins an MD5 operation, writing a new context.
+/*
+ * This processes one or more 64-byte data blocks, but does NOT update the bit
+ * counters.  There are no alignment requirements.
  */
-static void
-MD5Init (MD5_CTX *context)
-{
-    context->count[0] = context->count[1] = 0;
-    /* Load magic initialization constants.
-     */
-    context->state[0] = 0x67452301ul;
-    context->state[1] = 0xefcdab89ul;
-    context->state[2] = 0x98badcfeul;
-    context->state[3] = 0x10325476ul;
+static const void *body(MD5_CTX *ctx, const void *data, unsigned long size) {
+    const unsigned char *ptr;
+    MD5_u32plus a, b, c, d;
+    MD5_u32plus saved_a, saved_b, saved_c, saved_d;
+
+    ptr = (const unsigned char *) data;
+
+    a = ctx->a;
+    b = ctx->b;
+    c = ctx->c;
+    d = ctx->d;
+
+    do {
+        saved_a = a;
+        saved_b = b;
+        saved_c = c;
+        saved_d = d;
+
+/* Round 1 */
+        STEP(F, a, b, c, d, SET(0), 0xd76aa478, 7)
+        STEP(F, d, a, b, c, SET(1), 0xe8c7b756, 12)
+        STEP(F, c, d, a, b, SET(2), 0x242070db, 17)
+        STEP(F, b, c, d, a, SET(3), 0xc1bdceee, 22)
+        STEP(F, a, b, c, d, SET(4), 0xf57c0faf, 7)
+        STEP(F, d, a, b, c, SET(5), 0x4787c62a, 12)
+        STEP(F, c, d, a, b, SET(6), 0xa8304613, 17)
+        STEP(F, b, c, d, a, SET(7), 0xfd469501, 22)
+        STEP(F, a, b, c, d, SET(8), 0x698098d8, 7)
+        STEP(F, d, a, b, c, SET(9), 0x8b44f7af, 12)
+        STEP(F, c, d, a, b, SET(10), 0xffff5bb1, 17)
+        STEP(F, b, c, d, a, SET(11), 0x895cd7be, 22)
+        STEP(F, a, b, c, d, SET(12), 0x6b901122, 7)
+        STEP(F, d, a, b, c, SET(13), 0xfd987193, 12)
+        STEP(F, c, d, a, b, SET(14), 0xa679438e, 17)
+        STEP(F, b, c, d, a, SET(15), 0x49b40821, 22)
+
+/* Round 2 */
+        STEP(G, a, b, c, d, GET(1), 0xf61e2562, 5)
+        STEP(G, d, a, b, c, GET(6), 0xc040b340, 9)
+        STEP(G, c, d, a, b, GET(11), 0x265e5a51, 14)
+        STEP(G, b, c, d, a, GET(0), 0xe9b6c7aa, 20)
+        STEP(G, a, b, c, d, GET(5), 0xd62f105d, 5)
+        STEP(G, d, a, b, c, GET(10), 0x02441453, 9)
+        STEP(G, c, d, a, b, GET(15), 0xd8a1e681, 14)
+        STEP(G, b, c, d, a, GET(4), 0xe7d3fbc8, 20)
+        STEP(G, a, b, c, d, GET(9), 0x21e1cde6, 5)
+        STEP(G, d, a, b, c, GET(14), 0xc33707d6, 9)
+        STEP(G, c, d, a, b, GET(3), 0xf4d50d87, 14)
+        STEP(G, b, c, d, a, GET(8), 0x455a14ed, 20)
+        STEP(G, a, b, c, d, GET(13), 0xa9e3e905, 5)
+        STEP(G, d, a, b, c, GET(2), 0xfcefa3f8, 9)
+        STEP(G, c, d, a, b, GET(7), 0x676f02d9, 14)
+        STEP(G, b, c, d, a, GET(12), 0x8d2a4c8a, 20)
+
+/* Round 3 */
+        STEP(H, a, b, c, d, GET(5), 0xfffa3942, 4)
+        STEP(H2, d, a, b, c, GET(8), 0x8771f681, 11)
+        STEP(H, c, d, a, b, GET(11), 0x6d9d6122, 16)
+        STEP(H2, b, c, d, a, GET(14), 0xfde5380c, 23)
+        STEP(H, a, b, c, d, GET(1), 0xa4beea44, 4)
+        STEP(H2, d, a, b, c, GET(4), 0x4bdecfa9, 11)
+        STEP(H, c, d, a, b, GET(7), 0xf6bb4b60, 16)
+        STEP(H2, b, c, d, a, GET(10), 0xbebfbc70, 23)
+        STEP(H, a, b, c, d, GET(13), 0x289b7ec6, 4)
+        STEP(H2, d, a, b, c, GET(0), 0xeaa127fa, 11)
+        STEP(H, c, d, a, b, GET(3), 0xd4ef3085, 16)
+        STEP(H2, b, c, d, a, GET(6), 0x04881d05, 23)
+        STEP(H, a, b, c, d, GET(9), 0xd9d4d039, 4)
+        STEP(H2, d, a, b, c, GET(12), 0xe6db99e5, 11)
+        STEP(H, c, d, a, b, GET(15), 0x1fa27cf8, 16)
+        STEP(H2, b, c, d, a, GET(2), 0xc4ac5665, 23)
+
+/* Round 4 */
+        STEP(I, a, b, c, d, GET(0), 0xf4292244, 6)
+        STEP(I, d, a, b, c, GET(7), 0x432aff97, 10)
+        STEP(I, c, d, a, b, GET(14), 0xab9423a7, 15)
+        STEP(I, b, c, d, a, GET(5), 0xfc93a039, 21)
+        STEP(I, a, b, c, d, GET(12), 0x655b59c3, 6)
+        STEP(I, d, a, b, c, GET(3), 0x8f0ccc92, 10)
+        STEP(I, c, d, a, b, GET(10), 0xffeff47d, 15)
+        STEP(I, b, c, d, a, GET(1), 0x85845dd1, 21)
+        STEP(I, a, b, c, d, GET(8), 0x6fa87e4f, 6)
+        STEP(I, d, a, b, c, GET(15), 0xfe2ce6e0, 10)
+        STEP(I, c, d, a, b, GET(6), 0xa3014314, 15)
+        STEP(I, b, c, d, a, GET(13), 0x4e0811a1, 21)
+        STEP(I, a, b, c, d, GET(4), 0xf7537e82, 6)
+        STEP(I, d, a, b, c, GET(11), 0xbd3af235, 10)
+        STEP(I, c, d, a, b, GET(2), 0x2ad7d2bb, 15)
+        STEP(I, b, c, d, a, GET(9), 0xeb86d391, 21)
+
+        a += saved_a;
+        b += saved_b;
+        c += saved_c;
+        d += saved_d;
+
+        ptr += 64;
+    } while (size -= 64);
+
+    ctx->a = a;
+    ctx->b = b;
+    ctx->c = c;
+    ctx->d = d;
+
+    return ptr;
 }
 
-/* MD5 block update operation. Continues an MD5 message-digest
-  operation, processing another message block, and updating the
-  context.
- */
-static void
-MD5Update (MD5_CTX *context, const unsigned char *input, uint32_t inputLen)
-{
-    uint32_t i, idx, partLen;
+static void MD5_Init(MD5_CTX *ctx) {
+    ctx->a = 0x67452301;
+    ctx->b = 0xefcdab89;
+    ctx->c = 0x98badcfe;
+    ctx->d = 0x10325476;
 
-    /* Compute number of bytes mod 64 */
-    idx = (uint32_t)((context->count[0] >> 3) & 0x3F);
+    ctx->lo = 0;
+    ctx->hi = 0;
+}
 
-    /* Update number of bits */
-    if ((context->count[0] += ((uint32_t)inputLen << 3)) < ((uint32_t)inputLen << 3)) {
-        context->count[1]++;
-    }
-    context->count[1] += ((uint32_t)inputLen >> 29);
+static void MD5_Update(MD5_CTX *ctx, const void *data, unsigned long size) {
+    MD5_u32plus saved_lo;
+    unsigned long used, available;
 
-    partLen = 64 - idx;
+    saved_lo = ctx->lo;
+    if ((ctx->lo = (saved_lo + size) & 0x1fffffff) < saved_lo)
+        ctx->hi++;
+    ctx->hi += size >> 29;
 
-    /* Transform as many times as possible.
-     */
-    if (inputLen >= partLen) {
-        memcpy((unsigned char *)&context->buffer[idx], (const unsigned char *)input, partLen);
-        MD5Transform(context->state, context->buffer);
+    used = saved_lo & 0x3f;
 
-        for (i = partLen; i + 63 < inputLen; i += 64) {
-            MD5Transform (context->state, &input[i]);
+    if (used) {
+        available = 64 - used;
+
+        if (size < available) {
+            memcpy(&ctx->buffer[used], data, size);
+            return;
         }
-        idx = 0;
-    } else {
-        i = 0;
+
+        memcpy(&ctx->buffer[used], data, available);
+        data = (const unsigned char *) data + available;
+        size -= available;
+        body(ctx, ctx->buffer, 64);
     }
 
-    /* Buffer remaining input */
-    memcpy((unsigned char *)&context->buffer[idx], (const unsigned char *)&input[i], inputLen-i);
-}
+    if (size >= 64) {
+        data = body(ctx, data, size & ~(unsigned long) 0x3f);
+        size &= 0x3f;
+    }
 
-/* MD5 finalization. Ends an MD5 message-digest operation, writing the
-  the message digest and zeroizing the context.
- */
-static void
-MD5Final (unsigned char digest[16], MD5_CTX *context)
-{
-    unsigned char bits[8];
-    uint32_t idx, padLen;
-
-    /* Save number of bits */
-    Encode (bits, context->count, 8);
-
-    /* Pad out to 56 mod 64.
-     */
-    idx = (uint32_t)((context->count[0] >> 3) & 0x3f);
-    padLen = (idx < 56) ? (56 - idx) : (120 - idx);
-    MD5Update (context, PADDING, padLen);
-
-    /* Append length (before padding) */
-    MD5Update (context, bits, 8);
-    /* Store state in digest */
-    Encode (digest, context->state, 16);
-
-    /* Zeroize sensitive information.
-     */
-    memset ((unsigned char *)context, 0, sizeof (*context));
+    memcpy(ctx->buffer, data, size);
 }
 
-/* MD5 basic transformation. Transforms state based on block.
- */
-static void
-MD5Transform (uint32_t state[4], const unsigned char dblock[64])
-{
-    uint32_t a = state[0], b = state[1], c = state[2], d = state[3], x[16];
-
-    Decode (x, dblock, 64);
-
-    /* Round 1 */
-    FF (a, b, c, d, x[ 0], S11, 0xd76aa478ul); /* 1 */
-    FF (d, a, b, c, x[ 1], S12, 0xe8c7b756ul); /* 2 */
-    FF (c, d, a, b, x[ 2], S13, 0x242070dbul); /* 3 */
-    FF (b, c, d, a, x[ 3], S14, 0xc1bdceeeul); /* 4 */
-    FF (a, b, c, d, x[ 4], S11, 0xf57c0faful); /* 5 */
-    FF (d, a, b, c, x[ 5], S12, 0x4787c62aul); /* 6 */
-    FF (c, d, a, b, x[ 6], S13, 0xa8304613ul); /* 7 */
-    FF (b, c, d, a, x[ 7], S14, 0xfd469501ul); /* 8 */
-    FF (a, b, c, d, x[ 8], S11, 0x698098d8ul); /* 9 */
-    FF (d, a, b, c, x[ 9], S12, 0x8b44f7aful); /* 10 */
-    FF (c, d, a, b, x[10], S13, 0xffff5bb1ul); /* 11 */
-    FF (b, c, d, a, x[11], S14, 0x895cd7beul); /* 12 */
-    FF (a, b, c, d, x[12], S11, 0x6b901122ul); /* 13 */
-    FF (d, a, b, c, x[13], S12, 0xfd987193ul); /* 14 */
-    FF (c, d, a, b, x[14], S13, 0xa679438eul); /* 15 */
-    FF (b, c, d, a, x[15], S14, 0x49b40821ul); /* 16 */
-
-    /* Round 2 */
-    GG (a, b, c, d, x[ 1], S21, 0xf61e2562ul); /* 17 */
-    GG (d, a, b, c, x[ 6], S22, 0xc040b340ul); /* 18 */
-    GG (c, d, a, b, x[11], S23, 0x265e5a51ul); /* 19 */
-    GG (b, c, d, a, x[ 0], S24, 0xe9b6c7aaul); /* 20 */
-    GG (a, b, c, d, x[ 5], S21, 0xd62f105dul); /* 21 */
-    GG (d, a, b, c, x[10], S22,  0x2441453ul); /* 22 */
-    GG (c, d, a, b, x[15], S23, 0xd8a1e681ul); /* 23 */
-    GG (b, c, d, a, x[ 4], S24, 0xe7d3fbc8ul); /* 24 */
-    GG (a, b, c, d, x[ 9], S21, 0x21e1cde6ul); /* 25 */
-    GG (d, a, b, c, x[14], S22, 0xc33707d6ul); /* 26 */
-    GG (c, d, a, b, x[ 3], S23, 0xf4d50d87ul); /* 27 */
-    GG (b, c, d, a, x[ 8], S24, 0x455a14edul); /* 28 */
-    GG (a, b, c, d, x[13], S21, 0xa9e3e905ul); /* 29 */
-    GG (d, a, b, c, x[ 2], S22, 0xfcefa3f8ul); /* 30 */
-    GG (c, d, a, b, x[ 7], S23, 0x676f02d9ul); /* 31 */
-    GG (b, c, d, a, x[12], S24, 0x8d2a4c8aul); /* 32 */
-
-    /* Round 3 */
-    HH (a, b, c, d, x[ 5], S31, 0xfffa3942ul); /* 33 */
-    HH (d, a, b, c, x[ 8], S32, 0x8771f681ul); /* 34 */
-    HH (c, d, a, b, x[11], S33, 0x6d9d6122ul); /* 35 */
-    HH (b, c, d, a, x[14], S34, 0xfde5380cul); /* 36 */
-    HH (a, b, c, d, x[ 1], S31, 0xa4beea44ul); /* 37 */
-    HH (d, a, b, c, x[ 4], S32, 0x4bdecfa9ul); /* 38 */
-    HH (c, d, a, b, x[ 7], S33, 0xf6bb4b60ul); /* 39 */
-    HH (b, c, d, a, x[10], S34, 0xbebfbc70ul); /* 40 */
-    HH (a, b, c, d, x[13], S31, 0x289b7ec6ul); /* 41 */
-    HH (d, a, b, c, x[ 0], S32, 0xeaa127faul); /* 42 */
-    HH (c, d, a, b, x[ 3], S33, 0xd4ef3085ul); /* 43 */
-    HH (b, c, d, a, x[ 6], S34,  0x4881d05ul); /* 44 */
-    HH (a, b, c, d, x[ 9], S31, 0xd9d4d039ul); /* 45 */
-    HH (d, a, b, c, x[12], S32, 0xe6db99e5ul); /* 46 */
-    HH (c, d, a, b, x[15], S33, 0x1fa27cf8ul); /* 47 */
-    HH (b, c, d, a, x[ 2], S34, 0xc4ac5665ul); /* 48 */
-
-    /* Round 4 */
-    II (a, b, c, d, x[ 0], S41, 0xf4292244ul); /* 49 */
-    II (d, a, b, c, x[ 7], S42, 0x432aff97ul); /* 50 */
-    II (c, d, a, b, x[14], S43, 0xab9423a7ul); /* 51 */
-    II (b, c, d, a, x[ 5], S44, 0xfc93a039ul); /* 52 */
-    II (a, b, c, d, x[12], S41, 0x655b59c3ul); /* 53 */
-    II (d, a, b, c, x[ 3], S42, 0x8f0ccc92ul); /* 54 */
-    II (c, d, a, b, x[10], S43, 0xffeff47dul); /* 55 */
-    II (b, c, d, a, x[ 1], S44, 0x85845dd1ul); /* 56 */
-    II (a, b, c, d, x[ 8], S41, 0x6fa87e4ful); /* 57 */
-    II (d, a, b, c, x[15], S42, 0xfe2ce6e0ul); /* 58 */
-    II (c, d, a, b, x[ 6], S43, 0xa3014314ul); /* 59 */
-    II (b, c, d, a, x[13], S44, 0x4e0811a1ul); /* 60 */
-    II (a, b, c, d, x[ 4], S41, 0xf7537e82ul); /* 61 */
-    II (d, a, b, c, x[11], S42, 0xbd3af235ul); /* 62 */
-    II (c, d, a, b, x[ 2], S43, 0x2ad7d2bbul); /* 63 */
-    II (b, c, d, a, x[ 9], S44, 0xeb86d391ul); /* 64 */
-
-    state[0] += a;
-    state[1] += b;
-    state[2] += c;
-    state[3] += d;
-
-    /* Zeroize sensitive information.
-     */
-    memset((unsigned char *)x, 0, sizeof (x));
-}
+#define OUT(dst, src) \
+    (dst)[0] = (unsigned char)(src); \
+    (dst)[1] = (unsigned char)((src) >> 8); \
+    (dst)[2] = (unsigned char)((src) >> 16); \
+    (dst)[3] = (unsigned char)((src) >> 24);
+
+static void MD5_Final(unsigned char *result, MD5_CTX *ctx) {
+    unsigned long used, available;
+
+    used = ctx->lo & 0x3f;
+
+    ctx->buffer[used++] = 0x80;
 
-static void
-Encode (unsigned char *output, uint32_t *input, uint32_t len)
-{
-    uint32_t i, j;
+    available = 64 - used;
 
-    for (i = 0, j = 0; j < len; i++, j += 4) {
-        output[j] = (unsigned char)(input[i] & 0xff);
-        output[j+1] = (unsigned char)((input[i] >> 8) & 0xff);
-        output[j+2] = (unsigned char)((input[i] >> 16) & 0xff);
-        output[j+3] = (unsigned char)((input[i] >> 24) & 0xff);
+    if (available < 8) {
+        memset(&ctx->buffer[used], 0, available);
+        body(ctx, ctx->buffer, 64);
+        used = 0;
+        available = 64;
     }
-}
 
-/* Decodes input (unsigned char) into output (uint32_t). Assumes len is
-  a multiple of 4.
- */
+    memset(&ctx->buffer[used], 0, available - 8);
 
-static void
-Decode (uint32_t *output, const unsigned char *input, uint32_t len)
-{
-    uint32_t i, j;
+    ctx->lo <<= 3;
+    OUT(&ctx->buffer[56], ctx->lo)
+    OUT(&ctx->buffer[60], ctx->hi)
 
-    for (i = 0, j = 0; j < len; i++, j += 4)
-        output[i] = ((uint32_t)input[j]) | (((uint32_t)input[j+1]) << 8) |
-            (((uint32_t)input[j+2]) << 16) | (((uint32_t)input[j+3]) << 24);
-}
+    body(ctx, ctx->buffer, 64);
 
+    OUT(&result[0], ctx->a)
+    OUT(&result[4], ctx->b)
+    OUT(&result[8], ctx->c)
+    OUT(&result[12], ctx->d)
 
-/* --- END OF MD5 CODE --- */
+    memset(ctx, 0, sizeof(*ctx));
+}
 
-void fastc_md5sum(const void *s, size_t len, unsigned char *key)
-{
-	MD5_CTX m5;
-	MD5Init(&m5);
-	MD5Update(&m5, (const unsigned char *)s, len);
-	MD5Final(key, &m5);
+void fastc_md5sum(const void *s, size_t len, unsigned char *key) {
+    MD5_CTX m5;
+    MD5_Init(&m5);
+    MD5_Update(&m5, (const unsigned char *)s, len);
+    MD5_Final(key, &m5);
 }