gscifs/reference/libtinysmb/md4.c
2015-05-09 15:40:04 -04:00

301 lines
7.6 KiB
C

/****************************************************************************
* TinySMB
* Nintendo Wii/GameCube SMB implementation
*
* MD4 message digest
****************************************************************************/
#include <stdint.h>
#include <string.h>
/* Structure to save state of computation between the single steps. */
struct md4_ctx
{
uint32_t A;
uint32_t B;
uint32_t C;
uint32_t D;
uint32_t total[2];
uint32_t buflen;
uint32_t buffer[32];
};
# define MD4_DIGEST_SIZE 16
# define SWAP(n) \
(((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
#define BLOCKSIZE 4096
#if BLOCKSIZE % 64 != 0
# error "invalid BLOCKSIZE"
#endif
/* 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);
/* 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) */
static 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 inline 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. */
static 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 LEN bytes of BUFFER, accumulating context into CTX.
It is assumed that LEN % 64 == 0. */
static 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;
/* 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] += len;
if (ctx->total[0] < len)
++ctx->total[1];
/* 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;
}
}
/* Process the remaining bytes in the internal buffer and the usual
prolog according to the standard and write the result to RESBUF. */
static 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);
}
static 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
/* To check alignment gcc has an appropriate operator. Other
compilers don't. */
# if __GNUC__ >= 2
# define UNALIGNED_P(p) (((uintptr_t) p) % __alignof__ (uint32_t) != 0)
# else
# define alignof(type) offsetof (struct { char c; type x; }, x)
# define UNALIGNED_P(p) (((size_t) p) % alignof (uint32_t) != 0)
# endif
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;
}
}
/* 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);
}