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wget/lib/md4.c

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/* Functions to compute MD4 message digest of files or memory blocks.
according to the definition of MD4 in RFC 1320 from April 1992.
Copyright (C) 1995-1997, 1999-2003, 2005-2006, 2008-2023 Free Software
Foundation, Inc.
This file is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
This file 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 Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* Adapted by Simon Josefsson from gnulib md5.? and Libgcrypt
cipher/md4.c . */
#include <config.h>
/* Specification. */
#include "md4.h"
#include <stdint.h>
#include <string.h>
#include <sys/types.h>
#include <byteswap.h>
#ifdef WORDS_BIGENDIAN
# define SWAP(n) bswap_32 (n)
#else
# define SWAP(n) (n)
#endif
/* This array contains the bytes used to pad the buffer to the next
64-byte boundary. (RFC 1320, 3.1: Step 1) */
static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
/* Initialize structure containing state of computation.
(RFC 1320, 3.3: Step 3) */
void
md4_init_ctx (struct md4_ctx *ctx)
{
ctx->A = 0x67452301;
ctx->B = 0xefcdab89;
ctx->C = 0x98badcfe;
ctx->D = 0x10325476;
ctx->total[0] = ctx->total[1] = 0;
ctx->buflen = 0;
}
/* Copy the 4 byte value from v into the memory location pointed to by *cp,
If your architecture allows unaligned access this is equivalent to
* (uint32_t *) cp = v */
static void
set_uint32 (char *cp, uint32_t v)
{
memcpy (cp, &v, sizeof v);
}
/* Put result from CTX in first 16 bytes following RESBUF. The result
must be in little endian byte order. */
void *
md4_read_ctx (const struct md4_ctx *ctx, void *resbuf)
{
char *r = resbuf;
set_uint32 (r + 0 * sizeof ctx->A, SWAP (ctx->A));
set_uint32 (r + 1 * sizeof ctx->B, SWAP (ctx->B));
set_uint32 (r + 2 * sizeof ctx->C, SWAP (ctx->C));
set_uint32 (r + 3 * sizeof ctx->D, SWAP (ctx->D));
return resbuf;
}
/* Process the remaining bytes in the internal buffer and the usual
prolog according to the standard and write the result to RESBUF. */
void *
md4_finish_ctx (struct md4_ctx *ctx, void *resbuf)
{
/* Take yet unprocessed bytes into account. */
uint32_t bytes = ctx->buflen;
size_t pad;
/* Now count remaining bytes. */
ctx->total[0] += bytes;
if (ctx->total[0] < bytes)
++ctx->total[1];
pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
memcpy (&((char*)ctx->buffer)[bytes], fillbuf, pad);
/* Put the 64-bit file length in *bits* at the end of the buffer. */
ctx->buffer[(bytes + pad) / 4] = SWAP (ctx->total[0] << 3);
ctx->buffer[(bytes + pad) / 4 + 1] = SWAP ((ctx->total[1] << 3) |
(ctx->total[0] >> 29));
/* Process last bytes. */
md4_process_block (ctx->buffer, bytes + pad + 8, ctx);
return md4_read_ctx (ctx, resbuf);
}
/* Compute MD4 message digest for LEN bytes beginning at BUFFER. The
result is always in little endian byte order, so that a byte-wise
output yields to the wanted ASCII representation of the message
digest. */
void *
md4_buffer (const char *buffer, size_t len, void *resblock)
{
struct md4_ctx ctx;
/* Initialize the computation context. */
md4_init_ctx (&ctx);
/* Process whole buffer but last len % 64 bytes. */
md4_process_bytes (buffer, len, &ctx);
/* Put result in desired memory area. */
return md4_finish_ctx (&ctx, resblock);
}
void
md4_process_bytes (const void *buffer, size_t len, struct md4_ctx *ctx)
{
/* When we already have some bits in our internal buffer concatenate
both inputs first. */
if (ctx->buflen != 0)
{
size_t left_over = ctx->buflen;
size_t add = 128 - left_over > len ? len : 128 - left_over;
memcpy (&((char*)ctx->buffer)[left_over], buffer, add);
ctx->buflen += add;
if (ctx->buflen > 64)
{
md4_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
ctx->buflen &= 63;
/* The regions in the following copy operation cannot overlap. */
memcpy (ctx->buffer, &((char*)ctx->buffer)[(left_over + add) & ~63],
ctx->buflen);
}
buffer = (const char *) buffer + add;
len -= add;
}
/* Process available complete blocks. */
if (len >= 64)
{
#if !(_STRING_ARCH_unaligned || _STRING_INLINE_unaligned)
# define UNALIGNED_P(p) ((uintptr_t) (p) % alignof (uint32_t) != 0)
if (UNALIGNED_P (buffer))
while (len > 64)
{
md4_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
buffer = (const char *) buffer + 64;
len -= 64;
}
else
#endif
{
md4_process_block (buffer, len & ~63, ctx);
buffer = (const char *) buffer + (len & ~63);
len &= 63;
}
}
/* Move remaining bytes in internal buffer. */
if (len > 0)
{
size_t left_over = ctx->buflen;
memcpy (&((char*)ctx->buffer)[left_over], buffer, len);
left_over += len;
if (left_over >= 64)
{
md4_process_block (ctx->buffer, 64, ctx);
left_over -= 64;
memcpy (ctx->buffer, &ctx->buffer[16], left_over);
}
ctx->buflen = left_over;
}
}
/* --- Code below is the primary difference between md5.c and md4.c --- */
/* MD4 round constants */
#define K1 0x5a827999
#define K2 0x6ed9eba1
/* Round functions. */
#define F(x, y, z) ((z) ^ ((x) & ((y) ^ (z))))
#define G(x, y, z) (((x) & (y)) | ((x) & (z)) | ((y) & (z)))
#define H(x, y, z) ((x) ^ (y) ^ (z))
#define rol(x, n) (((x) << (n)) | ((uint32_t) (x) >> (32 - (n))))
#define R1(a,b,c,d,k,s) a=rol(a+F(b,c,d)+x[k],s);
#define R2(a,b,c,d,k,s) a=rol(a+G(b,c,d)+x[k]+K1,s);
#define R3(a,b,c,d,k,s) a=rol(a+H(b,c,d)+x[k]+K2,s);
/* Process LEN bytes of BUFFER, accumulating context into CTX.
It is assumed that LEN % 64 == 0. */
void
md4_process_block (const void *buffer, size_t len, struct md4_ctx *ctx)
{
const uint32_t *words = buffer;
size_t nwords = len / sizeof (uint32_t);
const uint32_t *endp = words + nwords;
uint32_t x[16];
uint32_t A = ctx->A;
uint32_t B = ctx->B;
uint32_t C = ctx->C;
uint32_t D = ctx->D;
uint32_t lolen = len;
/* First increment the byte count. RFC 1320 specifies the possible
length of the file up to 2^64 bits. Here we only compute the
number of bytes. Do a double word increment. */
ctx->total[0] += lolen;
ctx->total[1] += (len >> 31 >> 1) + (ctx->total[0] < lolen);
/* Process all bytes in the buffer with 64 bytes in each round of
the loop. */
while (words < endp)
{
int t;
for (t = 0; t < 16; t++)
{
x[t] = SWAP (*words);
words++;
}
/* Round 1. */
R1 (A, B, C, D, 0, 3);
R1 (D, A, B, C, 1, 7);
R1 (C, D, A, B, 2, 11);
R1 (B, C, D, A, 3, 19);
R1 (A, B, C, D, 4, 3);
R1 (D, A, B, C, 5, 7);
R1 (C, D, A, B, 6, 11);
R1 (B, C, D, A, 7, 19);
R1 (A, B, C, D, 8, 3);
R1 (D, A, B, C, 9, 7);
R1 (C, D, A, B, 10, 11);
R1 (B, C, D, A, 11, 19);
R1 (A, B, C, D, 12, 3);
R1 (D, A, B, C, 13, 7);
R1 (C, D, A, B, 14, 11);
R1 (B, C, D, A, 15, 19);
/* Round 2. */
R2 (A, B, C, D, 0, 3);
R2 (D, A, B, C, 4, 5);
R2 (C, D, A, B, 8, 9);
R2 (B, C, D, A, 12, 13);
R2 (A, B, C, D, 1, 3);
R2 (D, A, B, C, 5, 5);
R2 (C, D, A, B, 9, 9);
R2 (B, C, D, A, 13, 13);
R2 (A, B, C, D, 2, 3);
R2 (D, A, B, C, 6, 5);
R2 (C, D, A, B, 10, 9);
R2 (B, C, D, A, 14, 13);
R2 (A, B, C, D, 3, 3);
R2 (D, A, B, C, 7, 5);
R2 (C, D, A, B, 11, 9);
R2 (B, C, D, A, 15, 13);
/* Round 3. */
R3 (A, B, C, D, 0, 3);
R3 (D, A, B, C, 8, 9);
R3 (C, D, A, B, 4, 11);
R3 (B, C, D, A, 12, 15);
R3 (A, B, C, D, 2, 3);
R3 (D, A, B, C, 10, 9);
R3 (C, D, A, B, 6, 11);
R3 (B, C, D, A, 14, 15);
R3 (A, B, C, D, 1, 3);
R3 (D, A, B, C, 9, 9);
R3 (C, D, A, B, 5, 11);
R3 (B, C, D, A, 13, 15);
R3 (A, B, C, D, 3, 3);
R3 (D, A, B, C, 11, 9);
R3 (C, D, A, B, 7, 11);
R3 (B, C, D, A, 15, 15);
A = ctx->A += A;
B = ctx->B += B;
C = ctx->C += C;
D = ctx->D += D;
}
}
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