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elinks/src/util/md5.c
Witold Filipczyk 5a14b61c0d [register] Drop register
Compilers are smart and don't need such hints.
2021-12-03 12:34:00 +01:00

270 lines
8.0 KiB
C

/** MD5 implementation (RFC 1321)
* @file
*
* This code implements the MD5 message-digest algorithm. The algorithm is due
* to Ron Rivest.
*
* This code was written by Colin Plumb in 1993, no copyright is claimed. This
* code is in the public domain; do with it what you wish.
*
* This code was slightly modified to fit into Samba by abartlet@samba.org Jun
* 2001 and to fit the cifs vfs by Steve French sfrench@us.ibm.com. Grabbed from
* linux-2.6.9 one November afternoon 2004 and ELinksified' by jonas.
*
* Equivalent code is available from RSA Data Security, Inc. This code has been
* tested against that, and is equivalent, except that you don't need to include
* two pages of legalese with every copy. */
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <string.h>
#include "elinks.h"
#include "util/md5.h"
static void transform_md5(uint32_t buf[4], uint32_t const in[16]);
/** Swap the bytes of each uint32_t, if necessary.
* This code is harmless on little-endian machines.
* @todo FIXME: Optimize it away on little-endian machines. */
static void
reverse_md5_bytes(unsigned char *buf, unsigned int longs)
{
uint32_t t;
do {
t = (uint32_t) ((unsigned) buf[3] << 8 | buf[2]) << 16 |
((unsigned) buf[1] << 8 | buf[0]);
*(uint32_t *) buf = t;
buf += 4;
} while (--longs);
}
/** Start MD5 accumulation. Set bit count to 0 and buffer to mysterious
* initialization constants.
* @relates md5_context */
void
init_md5(struct md5_context *ctx)
{
ctx->buf[0] = 0x67452301;
ctx->buf[1] = 0xefcdab89;
ctx->buf[2] = 0x98badcfe;
ctx->buf[3] = 0x10325476;
ctx->bits[0] = 0;
ctx->bits[1] = 0;
}
/** Update context to reflect the concatenation of another buffer full
* of bytes.
* @relates md5_context */
void
update_md5(struct md5_context *ctx, const char *buf, unsigned long len)
{
uint32_t t;
/* Update bitcount */
t = ctx->bits[0];
if ((ctx->bits[0] = t + ((uint32_t) len << 3)) < t)
ctx->bits[1]++; /* Carry from low to high */
ctx->bits[1] += len >> 29;
t = (t >> 3) & 0x3f; /* Bytes already in shsInfo->data */
/* Handle any leading odd-sized chunks */
if (t) {
char *p = (char *) ctx->in + t;
t = 64 - t;
if (len < t) {
memmove(p, buf, len);
return;
}
memmove(p, buf, t);
reverse_md5_bytes(ctx->in, 16);
transform_md5(ctx->buf, (uint32_t *) ctx->in);
buf += t;
len -= t;
}
/* Process data in 64-byte chunks */
while (len >= 64) {
memmove(ctx->in, buf, 64);
reverse_md5_bytes(ctx->in, 16);
transform_md5(ctx->buf, (uint32_t *) ctx->in);
buf += 64;
len -= 64;
}
/* Handle any remaining bytes of data. */
memmove(ctx->in, buf, len);
}
/** Final wrapup - pad to 64-byte boundary with the bit pattern 1 0* (64-bit
* count of bits processed, MSB-first)
* @relates md5_context */
void
done_md5(struct md5_context *ctx, md5_digest_bin_T digest)
{
unsigned int count;
unsigned char *p;
/* Compute number of bytes mod 64 */
count = (ctx->bits[0] >> 3) & 0x3F;
/* Set the first char of padding to 0x80. This is safe since there is
always at least one byte free */
p = ctx->in + count;
*p++ = 0x80;
/* Bytes of padding needed to make 64 bytes */
count = 64 - 1 - count;
/* Pad out to 56 mod 64 */
if (count < 8) {
/* Two lots of padding: Pad the first block to 64 bytes */
memset(p, 0, count);
reverse_md5_bytes(ctx->in, 16);
transform_md5(ctx->buf, (uint32_t *) ctx->in);
/* Now fill the next block with 56 bytes */
memset(ctx->in, 0, 56);
} else {
/* Pad block to 56 bytes */
memset(p, 0, count - 8);
}
reverse_md5_bytes(ctx->in, 14);
/* Append length in bits and transform */
((uint32_t *) ctx->in)[14] = ctx->bits[0];
((uint32_t *) ctx->in)[15] = ctx->bits[1];
transform_md5(ctx->buf, (uint32_t *) ctx->in);
reverse_md5_bytes((unsigned char *)ctx->buf, 4);
memmove(digest, ctx->buf, 16);
memset(ctx, 0, sizeof(*ctx)); /* In case it's sensitive */
}
unsigned char *
digest_md5(const char *data, unsigned long length,
md5_digest_bin_T digest)
{
struct md5_context ctx;
init_md5(&ctx);
if (length != 0)
update_md5(&ctx, data, length);
done_md5(&ctx, digest);
return digest;
}
/* The four core functions - F1 is optimized somewhat */
/* #define F1(x, y, z) (x & y | ~x & z) */
#define F1(x, y, z) (z ^ (x & (y ^ z)))
#define F2(x, y, z) F1(z, x, y)
#define F3(x, y, z) (x ^ y ^ z)
#define F4(x, y, z) (y ^ (x | ~z))
/** This is the central step in the MD5 algorithm. */
#define MD5STEP(f, w, x, y, z, data, s) \
( w += f(x, y, z) + data, w = w<<s | w>>(32-s), w += x )
/** The core of the MD5 algorithm, this alters an existing MD5 hash to reflect
* the addition of 16 longwords of new data. md5_update() blocks the data and
* converts bytes into longwords for this routine. */
static void
transform_md5(uint32_t buf[4], uint32_t const in[16])
{
uint32_t a, b, c, d;
a = buf[0];
b = buf[1];
c = buf[2];
d = buf[3];
MD5STEP(F1, a, b, c, d, in[ 0] + 0xd76aa478, 7);
MD5STEP(F1, d, a, b, c, in[ 1] + 0xe8c7b756, 12);
MD5STEP(F1, c, d, a, b, in[ 2] + 0x242070db, 17);
MD5STEP(F1, b, c, d, a, in[ 3] + 0xc1bdceee, 22);
MD5STEP(F1, a, b, c, d, in[ 4] + 0xf57c0faf, 7);
MD5STEP(F1, d, a, b, c, in[ 5] + 0x4787c62a, 12);
MD5STEP(F1, c, d, a, b, in[ 6] + 0xa8304613, 17);
MD5STEP(F1, b, c, d, a, in[ 7] + 0xfd469501, 22);
MD5STEP(F1, a, b, c, d, in[ 8] + 0x698098d8, 7);
MD5STEP(F1, d, a, b, c, in[ 9] + 0x8b44f7af, 12);
MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
MD5STEP(F2, a, b, c, d, in[ 1] + 0xf61e2562, 5);
MD5STEP(F2, d, a, b, c, in[ 6] + 0xc040b340, 9);
MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
MD5STEP(F2, b, c, d, a, in[ 0] + 0xe9b6c7aa, 20);
MD5STEP(F2, a, b, c, d, in[ 5] + 0xd62f105d, 5);
MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
MD5STEP(F2, b, c, d, a, in[ 4] + 0xe7d3fbc8, 20);
MD5STEP(F2, a, b, c, d, in[ 9] + 0x21e1cde6, 5);
MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
MD5STEP(F2, c, d, a, b, in[ 3] + 0xf4d50d87, 14);
MD5STEP(F2, b, c, d, a, in[ 8] + 0x455a14ed, 20);
MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
MD5STEP(F2, d, a, b, c, in[ 2] + 0xfcefa3f8, 9);
MD5STEP(F2, c, d, a, b, in[ 7] + 0x676f02d9, 14);
MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
MD5STEP(F3, a, b, c, d, in[ 5] + 0xfffa3942, 4);
MD5STEP(F3, d, a, b, c, in[ 8] + 0x8771f681, 11);
MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
MD5STEP(F3, a, b, c, d, in[ 1] + 0xa4beea44, 4);
MD5STEP(F3, d, a, b, c, in[ 4] + 0x4bdecfa9, 11);
MD5STEP(F3, c, d, a, b, in[ 7] + 0xf6bb4b60, 16);
MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
MD5STEP(F3, d, a, b, c, in[ 0] + 0xeaa127fa, 11);
MD5STEP(F3, c, d, a, b, in[ 3] + 0xd4ef3085, 16);
MD5STEP(F3, b, c, d, a, in[ 6] + 0x04881d05, 23);
MD5STEP(F3, a, b, c, d, in[ 9] + 0xd9d4d039, 4);
MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
MD5STEP(F3, b, c, d, a, in[ 2] + 0xc4ac5665, 23);
MD5STEP(F4, a, b, c, d, in[ 0] + 0xf4292244, 6);
MD5STEP(F4, d, a, b, c, in[ 7] + 0x432aff97, 10);
MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
MD5STEP(F4, b, c, d, a, in[ 5] + 0xfc93a039, 21);
MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
MD5STEP(F4, d, a, b, c, in[ 3] + 0x8f0ccc92, 10);
MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
MD5STEP(F4, b, c, d, a, in[ 1] + 0x85845dd1, 21);
MD5STEP(F4, a, b, c, d, in[ 8] + 0x6fa87e4f, 6);
MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
MD5STEP(F4, c, d, a, b, in[ 6] + 0xa3014314, 15);
MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
MD5STEP(F4, a, b, c, d, in[ 4] + 0xf7537e82, 6);
MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
MD5STEP(F4, c, d, a, b, in[ 2] + 0x2ad7d2bb, 15);
MD5STEP(F4, b, c, d, a, in[ 9] + 0xeb86d391, 21);
buf[0] += a;
buf[1] += b;
buf[2] += c;
buf[3] += d;
}