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0e3082ee89
putty-source/sshmd5.c
Simon Tatham 0e3082ee89 New centralised binary-data marshalling system. 
I've finally got tired of all the code throughout PuTTY that repeats
the same logic about how to format the SSH binary primitives like
uint32, string, mpint. We've got reasonably organised code in ssh.c
that appends things like that to 'struct Packet'; something similar in
sftp.c which repeats a lot of the work; utility functions in various
places to format an mpint to feed to one or another hash function; and
no end of totally ad-hoc stuff in functions like public key blob
formatters which actually have to _count up_ the size of data
painstakingly, then malloc exactly that much and mess about with
PUT_32BIT.

It's time to bring all of that into one place, and stop repeating
myself in error-prone ways everywhere. The new marshal.h defines a
system in which I centralise all the actual marshalling functions, and
then layer a touch of C macro trickery on top to allow me to (look as
if I) pass a wide range of different types to those functions, as long
as the target type has been set up in the right way to have a write()
function.

This commit adds the new header and source file, and sets up some
general centralised types (strbuf and the various hash-function
contexts like SHA_State), but doesn't use the new calls for anything
yet.

(I've also renamed some internal functions in import.c which were
using the same names that I've just defined macros over. That won't
last long - those functions are going to go away soon, so the changed
names are strictly temporary.)
2018-05-25 14:36:16 +01:00

354 lines
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#include "ssh.h"
/*
* MD5 implementation for PuTTY. Written directly from the spec by
* Simon Tatham.
*/
/* ----------------------------------------------------------------------
* 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)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 * block)
{
uint32 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)
{
struct MD5Context *s = BinarySink_DOWNCAST(bs, struct MD5Context);
MD5Update(s, data, len);
}
void MD5Init(struct MD5Context *s)
{
MD5_Core_Init(&s->core);
s->blkused = 0;
s->lenhi = s->lenlo = 0;
BinarySink_INIT(s, MD5_BinarySink_write);
}
void MD5Update(struct MD5Context *s, unsigned char const *p, unsigned len)
{
unsigned char *q = (unsigned char *) p;
uint32 wordblock[16];
uint32 lenw = len;
int i;
/*
* Update the length field.
*/
s->lenlo += lenw;
s->lenhi += (s->lenlo < 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) s->block[i * 4 + 3]) << 24) |
(((uint32) s->block[i * 4 + 2]) << 16) |
(((uint32) s->block[i * 4 + 1]) << 8) |
(((uint32) s->block[i * 4 + 0]) << 0);
}
MD5_Block(&s->core, wordblock);
s->blkused = 0;
}
memcpy(s->block, q, len);
s->blkused = len;
}
}
void MD5Final(unsigned char output[16], struct MD5Context *s)
{
int i;
unsigned pad;
unsigned char c[64];
uint32 lenhi, lenlo;
if (s->blkused >= 56)
pad = 56 + 64 - s->blkused;
else
pad = 56 - s->blkused;
lenhi = (s->lenhi << 3) | (s->lenlo >> (32 - 3));
lenlo = (s->lenlo << 3);
memset(c, 0, pad);
c[0] = 0x80;
MD5Update(s, c, pad);
c[7] = (lenhi >> 24) & 0xFF;
c[6] = (lenhi >> 16) & 0xFF;
c[5] = (lenhi >> 8) & 0xFF;
c[4] = (lenhi >> 0) & 0xFF;
c[3] = (lenlo >> 24) & 0xFF;
c[2] = (lenlo >> 16) & 0xFF;
c[1] = (lenlo >> 8) & 0xFF;
c[0] = (lenlo >> 0) & 0xFF;
MD5Update(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;
}
}
void MD5Simple(void const *p, unsigned len, unsigned char output[16])
{
struct MD5Context s;
MD5Init(&s);
MD5Update(&s, (unsigned char const *)p, len);
MD5Final(output, &s);
smemclr(&s, sizeof(s));
}
/* ----------------------------------------------------------------------
* The above is the MD5 algorithm itself. Now we implement the
* HMAC wrapper on it.
*
* Some of these functions are exported directly, because they are
* useful elsewhere (SOCKS5 CHAP authentication uses HMAC-MD5).
*/
void *hmacmd5_make_context(void *cipher_ctx)
{
return snewn(3, struct MD5Context);
}
void hmacmd5_free_context(void *handle)
{
smemclr(handle, 3*sizeof(struct MD5Context));
sfree(handle);
}
void hmacmd5_key(void *handle, void const *keyv, int len)
{
struct MD5Context *keys = (struct MD5Context *)handle;
unsigned char foo[64];
unsigned char const *key = (unsigned char const *)keyv;
int i;
memset(foo, 0x36, 64);
for (i = 0; i < len && i < 64; i++)
foo[i] ^= key[i];
MD5Init(&keys[0]);
MD5Update(&keys[0], foo, 64);
memset(foo, 0x5C, 64);
for (i = 0; i < len && i < 64; i++)
foo[i] ^= key[i];
MD5Init(&keys[1]);
MD5Update(&keys[1], foo, 64);
smemclr(foo, 64); /* burn the evidence */
}
static void hmacmd5_key_16(void *handle, unsigned char *key)
{
hmacmd5_key(handle, key, 16);
}
static void hmacmd5_start(void *handle)
{
struct MD5Context *keys = (struct MD5Context *)handle;
keys[2] = keys[0]; /* structure copy */
BinarySink_COPIED(&keys[2]);
}
static void hmacmd5_bytes(void *handle, unsigned char const *blk, int len)
{
struct MD5Context *keys = (struct MD5Context *)handle;
MD5Update(&keys[2], blk, len);
}
static void hmacmd5_genresult(void *handle, unsigned char *hmac)
{
struct MD5Context *keys = (struct MD5Context *)handle;
struct MD5Context s;
unsigned char intermediate[16];
s = keys[2]; /* structure copy */
BinarySink_COPIED(&s);
MD5Final(intermediate, &s);
s = keys[1]; /* structure copy */
BinarySink_COPIED(&s);
MD5Update(&s, intermediate, 16);
MD5Final(hmac, &s);
}
static int hmacmd5_verresult(void *handle, unsigned char const *hmac)
{
unsigned char correct[16];
hmacmd5_genresult(handle, correct);
return smemeq(correct, hmac, 16);
}
static void hmacmd5_do_hmac_internal(void *handle,
unsigned char const *blk, int len,
unsigned char const *blk2, int len2,
unsigned char *hmac)
{
hmacmd5_start(handle);
hmacmd5_bytes(handle, blk, len);
if (blk2) hmacmd5_bytes(handle, blk2, len2);
hmacmd5_genresult(handle, hmac);
}
void hmacmd5_do_hmac(void *handle, unsigned char const *blk, int len,
unsigned char *hmac)
{
hmacmd5_do_hmac_internal(handle, blk, len, NULL, 0, hmac);
}
static void hmacmd5_do_hmac_ssh(void *handle, unsigned char const *blk, int len,
unsigned long seq, unsigned char *hmac)
{
unsigned char seqbuf[16];
PUT_32BIT_MSB_FIRST(seqbuf, seq);
hmacmd5_do_hmac_internal(handle, seqbuf, 4, blk, len, hmac);
}
static void hmacmd5_generate(void *handle, unsigned char *blk, int len,
unsigned long seq)
{
hmacmd5_do_hmac_ssh(handle, blk, len, seq, blk + len);
}
static int hmacmd5_verify(void *handle, unsigned char *blk, int len,
unsigned long seq)
{
unsigned char correct[16];
hmacmd5_do_hmac_ssh(handle, blk, len, seq, correct);
return smemeq(correct, blk + len, 16);
}
const struct ssh_mac ssh_hmac_md5 = {
hmacmd5_make_context, hmacmd5_free_context, hmacmd5_key_16,
hmacmd5_generate, hmacmd5_verify,
hmacmd5_start, hmacmd5_bytes, hmacmd5_genresult, hmacmd5_verresult,
"hmac-md5", "hmac-md5-etm@openssh.com",
16, 16,
"HMAC-MD5"
};
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