putty/sshmd5.c

266 строки
7.9 KiB
C

#include <assert.h>
#include "ssh.h"
/*
* MD5 implementation for PuTTY. Written directly from the spec by
* Simon Tatham.
*/
typedef struct {
uint32_t h[4];
} MD5_Core_State;
struct MD5Context {
MD5_Core_State core;
unsigned char block[64];
int blkused;
uint64_t len;
BinarySink_IMPLEMENTATION;
};
/* ----------------------------------------------------------------------
* Core MD5 algorithm: processes 16-word blocks into a message digest.
*/
#define F(x,y,z) ( ((x) & (y)) | ((~(x)) & (z)) )
#define G(x,y,z) ( ((x) & (z)) | ((~(z)) & (y)) )
#define H(x,y,z) ( (x) ^ (y) ^ (z) )
#define I(x,y,z) ( (y) ^ ( (x) | ~(z) ) )
#define rol(x,y) ( ((x) << (y)) | (((uint32_t)x) >> (32-y)) )
#define subround(f,w,x,y,z,k,s,ti) \
w = x + rol(w + f(x,y,z) + block[k] + ti, s)
static void MD5_Core_Init(MD5_Core_State * s)
{
s->h[0] = 0x67452301;
s->h[1] = 0xefcdab89;
s->h[2] = 0x98badcfe;
s->h[3] = 0x10325476;
}
static void MD5_Block(MD5_Core_State *s, uint32_t *block)
{
uint32_t a, b, c, d;
a = s->h[0];
b = s->h[1];
c = s->h[2];
d = s->h[3];
subround(F, a, b, c, d, 0, 7, 0xd76aa478);
subround(F, d, a, b, c, 1, 12, 0xe8c7b756);
subround(F, c, d, a, b, 2, 17, 0x242070db);
subround(F, b, c, d, a, 3, 22, 0xc1bdceee);
subround(F, a, b, c, d, 4, 7, 0xf57c0faf);
subround(F, d, a, b, c, 5, 12, 0x4787c62a);
subround(F, c, d, a, b, 6, 17, 0xa8304613);
subround(F, b, c, d, a, 7, 22, 0xfd469501);
subround(F, a, b, c, d, 8, 7, 0x698098d8);
subround(F, d, a, b, c, 9, 12, 0x8b44f7af);
subround(F, c, d, a, b, 10, 17, 0xffff5bb1);
subround(F, b, c, d, a, 11, 22, 0x895cd7be);
subround(F, a, b, c, d, 12, 7, 0x6b901122);
subround(F, d, a, b, c, 13, 12, 0xfd987193);
subround(F, c, d, a, b, 14, 17, 0xa679438e);
subround(F, b, c, d, a, 15, 22, 0x49b40821);
subround(G, a, b, c, d, 1, 5, 0xf61e2562);
subround(G, d, a, b, c, 6, 9, 0xc040b340);
subround(G, c, d, a, b, 11, 14, 0x265e5a51);
subround(G, b, c, d, a, 0, 20, 0xe9b6c7aa);
subround(G, a, b, c, d, 5, 5, 0xd62f105d);
subround(G, d, a, b, c, 10, 9, 0x02441453);
subround(G, c, d, a, b, 15, 14, 0xd8a1e681);
subround(G, b, c, d, a, 4, 20, 0xe7d3fbc8);
subround(G, a, b, c, d, 9, 5, 0x21e1cde6);
subround(G, d, a, b, c, 14, 9, 0xc33707d6);
subround(G, c, d, a, b, 3, 14, 0xf4d50d87);
subround(G, b, c, d, a, 8, 20, 0x455a14ed);
subround(G, a, b, c, d, 13, 5, 0xa9e3e905);
subround(G, d, a, b, c, 2, 9, 0xfcefa3f8);
subround(G, c, d, a, b, 7, 14, 0x676f02d9);
subround(G, b, c, d, a, 12, 20, 0x8d2a4c8a);
subround(H, a, b, c, d, 5, 4, 0xfffa3942);
subround(H, d, a, b, c, 8, 11, 0x8771f681);
subround(H, c, d, a, b, 11, 16, 0x6d9d6122);
subround(H, b, c, d, a, 14, 23, 0xfde5380c);
subround(H, a, b, c, d, 1, 4, 0xa4beea44);
subround(H, d, a, b, c, 4, 11, 0x4bdecfa9);
subround(H, c, d, a, b, 7, 16, 0xf6bb4b60);
subround(H, b, c, d, a, 10, 23, 0xbebfbc70);
subround(H, a, b, c, d, 13, 4, 0x289b7ec6);
subround(H, d, a, b, c, 0, 11, 0xeaa127fa);
subround(H, c, d, a, b, 3, 16, 0xd4ef3085);
subround(H, b, c, d, a, 6, 23, 0x04881d05);
subround(H, a, b, c, d, 9, 4, 0xd9d4d039);
subround(H, d, a, b, c, 12, 11, 0xe6db99e5);
subround(H, c, d, a, b, 15, 16, 0x1fa27cf8);
subround(H, b, c, d, a, 2, 23, 0xc4ac5665);
subround(I, a, b, c, d, 0, 6, 0xf4292244);
subround(I, d, a, b, c, 7, 10, 0x432aff97);
subround(I, c, d, a, b, 14, 15, 0xab9423a7);
subround(I, b, c, d, a, 5, 21, 0xfc93a039);
subround(I, a, b, c, d, 12, 6, 0x655b59c3);
subround(I, d, a, b, c, 3, 10, 0x8f0ccc92);
subround(I, c, d, a, b, 10, 15, 0xffeff47d);
subround(I, b, c, d, a, 1, 21, 0x85845dd1);
subround(I, a, b, c, d, 8, 6, 0x6fa87e4f);
subround(I, d, a, b, c, 15, 10, 0xfe2ce6e0);
subround(I, c, d, a, b, 6, 15, 0xa3014314);
subround(I, b, c, d, a, 13, 21, 0x4e0811a1);
subround(I, a, b, c, d, 4, 6, 0xf7537e82);
subround(I, d, a, b, c, 11, 10, 0xbd3af235);
subround(I, c, d, a, b, 2, 15, 0x2ad7d2bb);
subround(I, b, c, d, a, 9, 21, 0xeb86d391);
s->h[0] += a;
s->h[1] += b;
s->h[2] += c;
s->h[3] += d;
}
/* ----------------------------------------------------------------------
* Outer MD5 algorithm: take an arbitrary length byte string,
* convert it into 16-word blocks with the prescribed padding at
* the end, and pass those blocks to the core MD5 algorithm.
*/
#define BLKSIZE 64
static void MD5_BinarySink_write(BinarySink *bs, const void *data, size_t len);
static void MD5Init(struct MD5Context *s)
{
MD5_Core_Init(&s->core);
s->blkused = 0;
s->len = 0;
BinarySink_INIT(s, MD5_BinarySink_write);
}
static void MD5_BinarySink_write(BinarySink *bs, const void *data, size_t len)
{
struct MD5Context *s = BinarySink_DOWNCAST(bs, struct MD5Context);
const unsigned char *q = (const unsigned char *)data;
uint32_t wordblock[16];
uint32_t lenw = len;
int i;
assert(lenw == len);
/*
* Update the length field.
*/
s->len += lenw;
if (s->blkused + len < BLKSIZE) {
/*
* Trivial case: just add to the block.
*/
memcpy(s->block + s->blkused, q, len);
s->blkused += len;
} else {
/*
* We must complete and process at least one block.
*/
while (s->blkused + len >= BLKSIZE) {
memcpy(s->block + s->blkused, q, BLKSIZE - s->blkused);
q += BLKSIZE - s->blkused;
len -= BLKSIZE - s->blkused;
/* Now process the block. Gather bytes little-endian into words */
for (i = 0; i < 16; i++) {
wordblock[i] =
(((uint32_t) s->block[i * 4 + 3]) << 24) |
(((uint32_t) s->block[i * 4 + 2]) << 16) |
(((uint32_t) s->block[i * 4 + 1]) << 8) |
(((uint32_t) s->block[i * 4 + 0]) << 0);
}
MD5_Block(&s->core, wordblock);
s->blkused = 0;
}
memcpy(s->block, q, len);
s->blkused = len;
}
}
static void MD5Final(unsigned char output[16], struct MD5Context *s)
{
int i;
unsigned pad;
unsigned char c[64];
uint64_t len;
if (s->blkused >= 56)
pad = 56 + 64 - s->blkused;
else
pad = 56 - s->blkused;
len = (s->len << 3);
memset(c, 0, pad);
c[0] = 0x80;
put_data(s, c, pad);
PUT_64BIT_LSB_FIRST(c, len);
put_data(s, c, 8);
for (i = 0; i < 4; i++) {
output[4 * i + 3] = (s->core.h[i] >> 24) & 0xFF;
output[4 * i + 2] = (s->core.h[i] >> 16) & 0xFF;
output[4 * i + 1] = (s->core.h[i] >> 8) & 0xFF;
output[4 * i + 0] = (s->core.h[i] >> 0) & 0xFF;
}
}
/* ----------------------------------------------------------------------
* Thin abstraction for things where hashes are pluggable.
*/
struct md5_hash {
struct MD5Context state;
ssh_hash hash;
};
static ssh_hash *md5_new(const ssh_hashalg *alg)
{
struct md5_hash *h = snew(struct md5_hash);
h->hash.vt = alg;
BinarySink_DELEGATE_INIT(&h->hash, &h->state);
return &h->hash;
}
static void md5_reset(ssh_hash *hash)
{
struct md5_hash *h = container_of(hash, struct md5_hash, hash);
MD5Init(&h->state);
}
static void md5_copyfrom(ssh_hash *hcopy, ssh_hash *horig)
{
struct md5_hash *copy = container_of(hcopy, struct md5_hash, hash);
struct md5_hash *orig = container_of(horig, struct md5_hash, hash);
copy->state = orig->state;
BinarySink_COPIED(&copy->state);
}
static void md5_free(ssh_hash *hash)
{
struct md5_hash *h = container_of(hash, struct md5_hash, hash);
smemclr(h, sizeof(*h));
sfree(h);
}
static void md5_digest(ssh_hash *hash, unsigned char *output)
{
struct md5_hash *h = container_of(hash, struct md5_hash, hash);
MD5Final(output, &h->state);
}
const ssh_hashalg ssh_md5 = {
md5_new, md5_reset, md5_copyfrom, md5_digest, md5_free,
16, 64, HASHALG_NAMES_BARE("MD5"),
};