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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, 2008-2018 Free Software
+ Foundation, Inc.
+
+ This program is free software; you can redistribute it and/or modify it
+ under the terms of the GNU General Public License as published by the
+ Free Software Foundation; either version 3, or (at your option) any
+ later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU 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>
+
+#include "md4.h"
+
+#include <stdalign.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/types.h>
+
+#if USE_UNLOCKED_IO
+# include "unlocked-io.h"
+#endif
+
+#include <byteswap.h>
+#ifdef WORDS_BIGENDIAN
+# define SWAP(n) bswap_32 (n)
+#else
+# define SWAP(n) (n)
+#endif
+
+#define BLOCKSIZE 32768
+#if BLOCKSIZE % 64 != 0
+# error "invalid BLOCKSIZE"
+#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 bytes read from STREAM. The
+ resulting message digest number will be written into the 16 bytes
+ beginning at RESBLOCK. */
+int
+md4_stream (FILE * stream, void *resblock)
+{
+ struct md4_ctx ctx;
+ size_t sum;
+
+ char *buffer = malloc (BLOCKSIZE + 72);
+ if (!buffer)
+ return 1;
+
+ /* Initialize the computation context. */
+ md4_init_ctx (&ctx);
+
+ /* Iterate over full file contents. */
+ while (1)
+ {
+ /* We read the file in blocks of BLOCKSIZE bytes. One call of the
+ computation function processes the whole buffer so that with the
+ next round of the loop another block can be read. */
+ size_t n;
+ sum = 0;
+
+ /* Read block. Take care for partial reads. */
+ while (1)
+ {
+ n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
+
+ sum += n;
+
+ if (sum == BLOCKSIZE)
+ break;
+
+ if (n == 0)
+ {
+ /* Check for the error flag IFF N == 0, so that we don't
+ exit the loop after a partial read due to e.g., EAGAIN
+ or EWOULDBLOCK. */
+ if (ferror (stream))
+ {
+ free (buffer);
+ return 1;
+ }
+ goto process_partial_block;
+ }
+
+ /* We've read at least one byte, so ignore errors. But always
+ check for EOF, since feof may be true even though N > 0.
+ Otherwise, we could end up calling fread after EOF. */
+ if (feof (stream))
+ goto process_partial_block;
+ }
+
+ /* Process buffer with BLOCKSIZE bytes. Note that
+ BLOCKSIZE % 64 == 0
+ */
+ md4_process_block (buffer, BLOCKSIZE, &ctx);
+ }
+
+process_partial_block:;
+
+ /* Process any remaining bytes. */
+ if (sum > 0)
+ md4_process_bytes (buffer, sum, &ctx);
+
+ /* Construct result in desired memory. */
+ md4_finish_ctx (&ctx, resblock);
+ free (buffer);
+ return 0;
+}
+
+/* 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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