int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont,
BN_CTX *ctx)
{
int retn = 0;
#ifdef MONT_WORD
BIGNUM *t;
BN_CTX_start(ctx);
if ((t = BN_CTX_get(ctx)) && BN_copy(t, a)) {
retn = bn_from_montgomery_word(ret, t, mont);
bn_correct_top(ret);
bn_check_top(ret);
}
BN_CTX_end(ctx);
#else /* !MONT_WORD */
BIGNUM *t1, *t2;
BN_CTX_start(ctx);
t1 = BN_CTX_get(ctx);
t2 = BN_CTX_get(ctx);
if (t1 == NULL || t2 == NULL)
goto err;
if (!BN_copy(t1, a))
goto err;
BN_mask_bits(t1, mont->ri);
if (!BN_mul(t2, t1, &mont->Ni, ctx))
goto err;
BN_mask_bits(t2, mont->ri);
if (!BN_mul(t1, t2, &mont->N, ctx))
goto err;
if (!BN_add(t2, a, t1))
goto err;
if (!BN_rshift(ret, t2, mont->ri))
goto err;
if (BN_ucmp(ret, &(mont->N)) >= 0) {
if (!BN_usub(ret, ret, &(mont->N)))
goto err;
}
retn = 1;
bn_check_top(ret);
err:
BN_CTX_end(ctx);
#endif /* MONT_WORD */
return (retn);
}
static void
to_ascii(void)
{
struct number *n;
struct value *value;
char str[2];
value = pop();
if (value != NULL) {
str[1] = '\0';
switch (value->type) {
case BCODE_NONE:
return;
case BCODE_NUMBER:
n = value->u.num;
normalize(n, 0);
if (BN_num_bits(n->number) > 8)
bn_check(BN_mask_bits(n->number, 8));
str[0] = (char)BN_get_word(n->number);
break;
case BCODE_STRING:
str[0] = value->u.string[0];
break;
}
stack_free_value(value);
push_string(bstrdup(str));
}
}
/*
* rsa_get_exponent(): - Get the public exponent from an RSA key
*/
static int rsa_get_exponent(RSA *key, uint64_t *e)
{
int ret;
BIGNUM *bn_te;
uint64_t te;
ret = -EINVAL;
bn_te = NULL;
if (!e)
goto cleanup;
if (BN_num_bits(key->e) > 64)
goto cleanup;
*e = BN_get_word(key->e);
if (BN_num_bits(key->e) < 33) {
ret = 0;
goto cleanup;
}
bn_te = BN_dup(key->e);
if (!bn_te)
goto cleanup;
if (!BN_rshift(bn_te, bn_te, 32))
goto cleanup;
if (!BN_mask_bits(bn_te, 32))
goto cleanup;
te = BN_get_word(bn_te);
te <<= 32;
*e |= te;
ret = 0;
cleanup:
if (bn_te)
BN_free(bn_te);
return ret;
}
int
dsa_builtin_paramgen(DSA *ret, size_t bits, size_t qbits, const EVP_MD *evpmd,
const unsigned char *seed_in, size_t seed_len, unsigned char *seed_out,
int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
{
int ok = 0;
unsigned char seed[SHA256_DIGEST_LENGTH];
unsigned char md[SHA256_DIGEST_LENGTH];
unsigned char buf[SHA256_DIGEST_LENGTH], buf2[SHA256_DIGEST_LENGTH];
BIGNUM *r0, *W, *X, *c, *test;
BIGNUM *g = NULL, *q = NULL, *p = NULL;
BN_MONT_CTX *mont = NULL;
int i, k, n = 0, m = 0, qsize = qbits >> 3;
int counter = 0;
int r = 0;
BN_CTX *ctx = NULL;
unsigned int h = 2;
if (qsize != SHA_DIGEST_LENGTH && qsize != SHA224_DIGEST_LENGTH &&
qsize != SHA256_DIGEST_LENGTH)
/* invalid q size */
return 0;
if (evpmd == NULL)
/* use SHA1 as default */
evpmd = EVP_sha1();
if (bits < 512)
bits = 512;
bits = (bits + 63) / 64 * 64;
/*
* NB: seed_len == 0 is special case: copy generated seed to
* seed_in if it is not NULL.
*/
if (seed_len && seed_len < (size_t)qsize)
seed_in = NULL; /* seed buffer too small -- ignore */
/*
* App. 2.2 of FIPS PUB 186 allows larger SEED,
* but our internal buffers are restricted to 160 bits
*/
if (seed_len > (size_t)qsize)
seed_len = qsize;
if (seed_in != NULL)
memcpy(seed, seed_in, seed_len);
if ((ctx=BN_CTX_new()) == NULL)
goto err;
if ((mont=BN_MONT_CTX_new()) == NULL)
goto err;
BN_CTX_start(ctx);
r0 = BN_CTX_get(ctx);
g = BN_CTX_get(ctx);
W = BN_CTX_get(ctx);
q = BN_CTX_get(ctx);
X = BN_CTX_get(ctx);
c = BN_CTX_get(ctx);
p = BN_CTX_get(ctx);
test = BN_CTX_get(ctx);
if (!BN_lshift(test, BN_value_one(), bits - 1))
goto err;
for (;;) {
for (;;) { /* find q */
int seed_is_random;
/* step 1 */
if (!BN_GENCB_call(cb, 0, m++))
goto err;
if (!seed_len) {
RAND_pseudo_bytes(seed, qsize);
seed_is_random = 1;
} else {
seed_is_random = 0;
/* use random seed if 'seed_in' turns out
to be bad */
seed_len = 0;
}
memcpy(buf, seed, qsize);
memcpy(buf2, seed, qsize);
/* precompute "SEED + 1" for step 7: */
for (i = qsize - 1; i >= 0; i--) {
buf[i]++;
if (buf[i] != 0)
break;
}
/* step 2 */
if (!EVP_Digest(seed, qsize, md, NULL, evpmd, NULL))
goto err;
if (!EVP_Digest(buf, qsize, buf2, NULL, evpmd, NULL))
goto err;
for (i = 0; i < qsize; i++)
md[i] ^= buf2[i];
/* step 3 */
md[0] |= 0x80;
md[qsize - 1] |= 0x01;
if (!BN_bin2bn(md, qsize, q))
goto err;
/* step 4 */
r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
seed_is_random, cb);
if (r > 0)
break;
if (r != 0)
goto err;
/* do a callback call */
/* step 5 */
}
if (!BN_GENCB_call(cb, 2, 0))
goto err;
if (!BN_GENCB_call(cb, 3, 0))
goto err;
/* step 6 */
counter = 0;
/* "offset = 2" */
n = (bits - 1) / 160;
for (;;) {
if (counter != 0 && !BN_GENCB_call(cb, 0, counter))
goto err;
/* step 7 */
BN_zero(W);
/* now 'buf' contains "SEED + offset - 1" */
for (k = 0; k <= n; k++) {
/* obtain "SEED + offset + k" by incrementing: */
for (i = qsize - 1; i >= 0; i--) {
buf[i]++;
if (buf[i] != 0)
break;
}
if (!EVP_Digest(buf, qsize, md ,NULL, evpmd,
NULL))
goto err;
/* step 8 */
if (!BN_bin2bn(md, qsize, r0))
goto err;
if (!BN_lshift(r0, r0, (qsize << 3) * k))
goto err;
if (!BN_add(W, W, r0))
goto err;
}
/* more of step 8 */
if (!BN_mask_bits(W, bits - 1))
goto err;
if (!BN_copy(X, W))
goto err;
if (!BN_add(X, X, test))
goto err;
/* step 9 */
if (!BN_lshift1(r0, q))
goto err;
if (!BN_mod(c, X, r0, ctx))
goto err;
if (!BN_sub(r0, c, BN_value_one()))
goto err;
if (!BN_sub(p, X, r0))
goto err;
/* step 10 */
if (BN_cmp(p, test) >= 0) {
/* step 11 */
r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
ctx, 1, cb);
if (r > 0)
goto end; /* found it */
if (r != 0)
goto err;
}
/* step 13 */
counter++;
/* "offset = offset + n + 1" */
/* step 14 */
if (counter >= 4096)
break;
}
}
end:
if (!BN_GENCB_call(cb, 2, 1))
goto err;
/* We now need to generate g */
/* Set r0=(p-1)/q */
if (!BN_sub(test, p, BN_value_one()))
goto err;
if (!BN_div(r0, NULL, test, q, ctx))
goto err;
if (!BN_set_word(test, h))
goto err;
if (!BN_MONT_CTX_set(mont, p, ctx))
goto err;
for (;;) {
/* g=test^r0%p */
if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
goto err;
if (!BN_is_one(g))
break;
if (!BN_add(test, test, BN_value_one()))
goto err;
h++;
}
if (!BN_GENCB_call(cb, 3, 1))
goto err;
ok = 1;
err:
if (ok) {
if (ret->p)
BN_free(ret->p);
if (ret->q)
BN_free(ret->q);
if (ret->g)
BN_free(ret->g);
ret->p = BN_dup(p);
ret->q = BN_dup(q);
ret->g = BN_dup(g);
if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
ok = 0;
goto err;
}
if (counter_ret != NULL)
*counter_ret = counter;
if (h_ret != NULL)
*h_ret = h;
if (seed_out)
memcpy(seed_out, seed, qsize);
}
if (ctx) {
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (mont != NULL)
BN_MONT_CTX_free(mont);
return ok;
}
int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont,
BN_CTX *ctx)
{
int retn=0;
#ifdef MONT_WORD
BIGNUM *n,*r;
BN_ULONG *ap,*np,*rp,n0,v,*nrp;
int al,nl,max,i,x,ri;
BN_CTX_start(ctx);
if ((r = BN_CTX_get(ctx)) == NULL) goto err;
if (!BN_copy(r,a)) goto err;
n= &(mont->N);
ap=a->d;
/* mont->ri is the size of mont->N in bits (rounded up
to the word size) */
al=ri=mont->ri/BN_BITS2;
nl=n->top;
if ((al == 0) || (nl == 0)) { r->top=0; return(1); }
max=(nl+al+1); /* allow for overflow (no?) XXX */
if (bn_wexpand(r,max) == NULL) goto err;
r->neg=a->neg^n->neg;
np=n->d;
rp=r->d;
nrp= &(r->d[nl]);
/* clear the top words of T */
#if 1
for (i=r->top; i<max; i++) /* memset? XXX */
r->d[i]=0;
#else
memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG));
#endif
r->top=max;
n0=mont->n0;
#ifdef BN_COUNT
fprintf(stderr,"word BN_from_montgomery %d * %d\n",nl,nl);
#endif
for (i=0; i<nl; i++)
{
#ifdef __TANDEM
{
long long t1;
long long t2;
long long t3;
t1 = rp[0] * (n0 & 0177777);
t2 = 037777600000l;
t2 = n0 & t2;
t3 = rp[0] & 0177777;
t2 = (t3 * t2) & BN_MASK2;
t1 = t1 + t2;
v=bn_mul_add_words(rp,np,nl,(BN_ULONG) t1);
}
#else
v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2);
#endif
nrp++;
rp++;
if (((nrp[-1]+=v)&BN_MASK2) >= v)
continue;
else
{
if (((++nrp[0])&BN_MASK2) != 0) continue;
if (((++nrp[1])&BN_MASK2) != 0) continue;
for (x=2; (((++nrp[x])&BN_MASK2) == 0); x++) ;
}
}
bn_correct_top(r);
/* mont->ri will be a multiple of the word size and below code
* is kind of BN_rshift(ret,r,mont->ri) equivalent */
if (r->top <= ri)
{
ret->top=0;
retn=1;
goto err;
}
al=r->top-ri;
# define BRANCH_FREE 1
# if BRANCH_FREE
if (bn_wexpand(ret,ri) == NULL) goto err;
x=0-(((al-ri)>>(sizeof(al)*8-1))&1);
ret->top=x=(ri&~x)|(al&x); /* min(ri,al) */
ret->neg=r->neg;
rp=ret->d;
ap=&(r->d[ri]);
{
size_t m1,m2;
v=bn_sub_words(rp,ap,np,ri);
/* this ----------------^^ works even in al<ri case
* thanks to zealous zeroing of top of the vector in the
* beginning. */
/* if (al==ri && !v) || al>ri) nrp=rp; else nrp=ap; */
/* in other words if subtraction result is real, then
* trick unconditional memcpy below to perform in-place
* "refresh" instead of actual copy. */
m1=0-(size_t)(((al-ri)>>(sizeof(al)*8-1))&1); /* al<ri */
m2=0-(size_t)(((ri-al)>>(sizeof(al)*8-1))&1); /* al>ri */
m1|=m2; /* (al!=ri) */
m1|=(0-(size_t)v); /* (al!=ri || v) */
m1&=~m2; /* (al!=ri || v) && !al>ri */
nrp=(BN_ULONG *)(((size_t)rp&~m1)|((size_t)ap&m1));
}
/* 'i<ri' is chosen to eliminate dependency on input data, even
* though it results in redundant copy in al<ri case. */
for (i=0,ri-=4; i<ri; i+=4)
{
BN_ULONG t1,t2,t3,t4;
t1=nrp[i+0];
t2=nrp[i+1];
t3=nrp[i+2]; ap[i+0]=0;
t4=nrp[i+3]; ap[i+1]=0;
rp[i+0]=t1; ap[i+2]=0;
rp[i+1]=t2; ap[i+3]=0;
rp[i+2]=t3;
rp[i+3]=t4;
}
for (ri+=4; i<ri; i++)
rp[i]=nrp[i], ap[i]=0;
bn_correct_top(r);
bn_correct_top(ret);
# else
if (bn_wexpand(ret,al) == NULL) goto err;
ret->top=al;
ret->neg=r->neg;
rp=ret->d;
ap=&(r->d[ri]);
al-=4;
for (i=0; i<al; i+=4)
{
BN_ULONG t1,t2,t3,t4;
t1=ap[i+0];
t2=ap[i+1];
t3=ap[i+2];
t4=ap[i+3];
rp[i+0]=t1;
rp[i+1]=t2;
rp[i+2]=t3;
rp[i+3]=t4;
}
al+=4;
for (; i<al; i++)
rp[i]=ap[i];
# endif
#else /* !MONT_WORD */
BIGNUM *t1,*t2;
BN_CTX_start(ctx);
t1 = BN_CTX_get(ctx);
t2 = BN_CTX_get(ctx);
if (t1 == NULL || t2 == NULL) goto err;
if (!BN_copy(t1,a)) goto err;
BN_mask_bits(t1,mont->ri);
if (!BN_mul(t2,t1,&mont->Ni,ctx)) goto err;
BN_mask_bits(t2,mont->ri);
if (!BN_mul(t1,t2,&mont->N,ctx)) goto err;
if (!BN_add(t2,a,t1)) goto err;
if (!BN_rshift(ret,t2,mont->ri)) goto err;
#endif /* MONT_WORD */
#if !defined(BRANCH_FREE) || BRANCH_FREE==0
if (BN_ucmp(ret, &(mont->N)) >= 0)
{
if (!BN_usub(ret,ret,&(mont->N))) goto err;
}
#endif
retn=1;
bn_check_top(ret);
err:
BN_CTX_end(ctx);
return(retn);
}
/*
* SSH1 key exchange
*/
void
do_ssh1_kex(void)
{
int i, len;
int rsafail = 0;
BIGNUM *session_key_int;
u_char session_key[SSH_SESSION_KEY_LENGTH];
u_char cookie[8];
u_int cipher_type, auth_mask, protocol_flags;
u_int32_t rnd = 0;
/*
* Generate check bytes that the client must send back in the user
* packet in order for it to be accepted; this is used to defy ip
* spoofing attacks. Note that this only works against somebody
* doing IP spoofing from a remote machine; any machine on the local
* network can still see outgoing packets and catch the random
* cookie. This only affects rhosts authentication, and this is one
* of the reasons why it is inherently insecure.
*/
for (i = 0; i < 8; i++) {
if (i % 4 == 0)
rnd = arc4random();
cookie[i] = rnd & 0xff;
rnd >>= 8;
}
/*
* Send our public key. We include in the packet 64 bits of random
* data that must be matched in the reply in order to prevent IP
* spoofing.
*/
packet_start(SSH_SMSG_PUBLIC_KEY);
for (i = 0; i < 8; i++)
packet_put_char(cookie[i]);
/* Store our public server RSA key. */
packet_put_int(BN_num_bits(sensitive_data.server_key->rsa->n));
packet_put_bignum(sensitive_data.server_key->rsa->e);
packet_put_bignum(sensitive_data.server_key->rsa->n);
/* Store our public host RSA key. */
packet_put_int(BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
packet_put_bignum(sensitive_data.ssh1_host_key->rsa->e);
packet_put_bignum(sensitive_data.ssh1_host_key->rsa->n);
/* Put protocol flags. */
packet_put_int(SSH_PROTOFLAG_HOST_IN_FWD_OPEN);
/* Declare which ciphers we support. */
packet_put_int(cipher_mask_ssh1(0));
/* Declare supported authentication types. */
auth_mask = 0;
if (options.rhosts_rsa_authentication)
auth_mask |= 1 << SSH_AUTH_RHOSTS_RSA;
if (options.rsa_authentication)
auth_mask |= 1 << SSH_AUTH_RSA;
if (options.challenge_response_authentication == 1)
auth_mask |= 1 << SSH_AUTH_TIS;
if (options.password_authentication)
auth_mask |= 1 << SSH_AUTH_PASSWORD;
packet_put_int(auth_mask);
/* Send the packet and wait for it to be sent. */
packet_send();
packet_write_wait();
debug("Sent %d bit server key and %d bit host key.",
BN_num_bits(sensitive_data.server_key->rsa->n),
BN_num_bits(sensitive_data.ssh1_host_key->rsa->n));
/* Read clients reply (cipher type and session key). */
packet_read_expect(SSH_CMSG_SESSION_KEY);
/* Get cipher type and check whether we accept this. */
cipher_type = packet_get_char();
if (!(cipher_mask_ssh1(0) & (1 << cipher_type)))
packet_disconnect("Warning: client selects unsupported cipher.");
/* Get check bytes from the packet. These must match those we
sent earlier with the public key packet. */
for (i = 0; i < 8; i++)
if (cookie[i] != packet_get_char())
packet_disconnect("IP Spoofing check bytes do not match.");
debug("Encryption type: %.200s", cipher_name(cipher_type));
/* Get the encrypted integer. */
if ((session_key_int = BN_new()) == NULL)
fatal("do_ssh1_kex: BN_new failed");
packet_get_bignum(session_key_int);
protocol_flags = packet_get_int();
packet_set_protocol_flags(protocol_flags);
packet_check_eom();
/* Decrypt session_key_int using host/server keys */
rsafail = PRIVSEP(ssh1_session_key(session_key_int));
/*
* Extract session key from the decrypted integer. The key is in the
* least significant 256 bits of the integer; the first byte of the
* key is in the highest bits.
*/
if (!rsafail) {
BN_mask_bits(session_key_int, sizeof(session_key) * 8);
len = BN_num_bytes(session_key_int);
if (len < 0 || len > sizeof(session_key)) {
error("do_connection: bad session key len from %s: "
"session_key_int %d > sizeof(session_key) %lu",
get_remote_ipaddr(), len, (u_long)sizeof(session_key));
rsafail++;
} else {
memset(session_key, 0, sizeof(session_key));
BN_bn2bin(session_key_int,
session_key + sizeof(session_key) - len);
derive_ssh1_session_id(
sensitive_data.ssh1_host_key->rsa->n,
sensitive_data.server_key->rsa->n,
cookie, session_id);
/*
* Xor the first 16 bytes of the session key with the
* session id.
*/
for (i = 0; i < 16; i++)
session_key[i] ^= session_id[i];
}
}
if (rsafail) {
int bytes = BN_num_bytes(session_key_int);
u_char *buf = xmalloc(bytes);
MD5_CTX md;
logit("do_connection: generating a fake encryption key");
BN_bn2bin(session_key_int, buf);
MD5_Init(&md);
MD5_Update(&md, buf, bytes);
MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
MD5_Final(session_key, &md);
MD5_Init(&md);
MD5_Update(&md, session_key, 16);
MD5_Update(&md, buf, bytes);
MD5_Update(&md, sensitive_data.ssh1_cookie, SSH_SESSION_KEY_LENGTH);
MD5_Final(session_key + 16, &md);
memset(buf, 0, bytes);
xfree(buf);
for (i = 0; i < 16; i++)
session_id[i] = session_key[i] ^ session_key[i + 16];
}
/* Destroy the private and public keys. No longer. */
destroy_sensitive_data();
if (use_privsep)
mm_ssh1_session_id(session_id);
/* Destroy the decrypted integer. It is no longer needed. */
BN_clear_free(session_key_int);
/* Set the session key. From this on all communications will be encrypted. */
packet_set_encryption_key(session_key, SSH_SESSION_KEY_LENGTH, cipher_type);
/* Destroy our copy of the session key. It is no longer needed. */
memset(session_key, 0, sizeof(session_key));
debug("Received session key; encryption turned on.");
/* Send an acknowledgment packet. Note that this packet is sent encrypted. */
packet_start(SSH_SMSG_SUCCESS);
packet_send();
packet_write_wait();
}
DSA *DSA_generate_parameters(int bits,
unsigned char *seed_in, int seed_len,
int *counter_ret, unsigned long *h_ret,
void (*callback)(int, int, void *),
void *cb_arg)
{
int ok=0;
unsigned char seed[SHA_DIGEST_LENGTH];
unsigned char md[SHA_DIGEST_LENGTH];
unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
BIGNUM *r0,*W,*X,*c,*test;
BIGNUM *g=NULL,*q=NULL,*p=NULL;
BN_MONT_CTX *mont=NULL;
int k,n=0,i,b,m=0;
int counter=0;
int r=0;
BN_CTX *ctx=NULL,*ctx2=NULL,*ctx3=NULL;
unsigned int h=2;
DSA *ret=NULL;
if (bits < 512) bits=512;
bits=(bits+63)/64*64;
if (seed_len < 20)
seed_in = NULL; /* seed buffer too small -- ignore */
if (seed_len > 20)
seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
* but our internal buffers are restricted to 160 bits*/
if ((seed_in != NULL) && (seed_len == 20))
memcpy(seed,seed_in,seed_len);
if ((ctx=BN_CTX_new()) == NULL) goto err;
if ((ctx2=BN_CTX_new()) == NULL) goto err;
if ((ctx3=BN_CTX_new()) == NULL) goto err;
if ((ret=DSA_new()) == NULL) goto err;
if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
BN_CTX_start(ctx2);
r0 = BN_CTX_get(ctx2);
g = BN_CTX_get(ctx2);
W = BN_CTX_get(ctx2);
q = BN_CTX_get(ctx2);
X = BN_CTX_get(ctx2);
c = BN_CTX_get(ctx2);
p = BN_CTX_get(ctx2);
test = BN_CTX_get(ctx2);
if (test == NULL) goto err;
if (!BN_lshift(test,BN_value_one(),bits-1)) goto err;
for (;;)
{
for (;;) /* find q */
{
int seed_is_random;
/* step 1 */
if (callback != NULL) callback(0,m++,cb_arg);
if (!seed_len)
{
RAND_pseudo_bytes(seed,SHA_DIGEST_LENGTH);
seed_is_random = 1;
}
else
{
seed_is_random = 0;
seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
}
memcpy(buf,seed,SHA_DIGEST_LENGTH);
memcpy(buf2,seed,SHA_DIGEST_LENGTH);
/* precompute "SEED + 1" for step 7: */
for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
{
buf[i]++;
if (buf[i] != 0) break;
}
/* step 2 */
EVP_Digest(seed,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
EVP_Digest(buf,SHA_DIGEST_LENGTH,buf2,NULL,HASH, NULL);
for (i=0; i<SHA_DIGEST_LENGTH; i++)
md[i]^=buf2[i];
/* step 3 */
md[0]|=0x80;
md[SHA_DIGEST_LENGTH-1]|=0x01;
if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) goto err;
/* step 4 */
r = BN_is_prime_fasttest(q, DSS_prime_checks, callback, ctx3, cb_arg, seed_is_random);
if (r > 0)
break;
if (r != 0)
goto err;
/* do a callback call */
/* step 5 */
}
if (callback != NULL) callback(2,0,cb_arg);
if (callback != NULL) callback(3,0,cb_arg);
/* step 6 */
counter=0;
/* "offset = 2" */
n=(bits-1)/160;
b=(bits-1)-n*160;
for (;;)
{
if (callback != NULL && counter != 0)
callback(0,counter,cb_arg);
/* step 7 */
if (!BN_zero(W)) goto err;
/* now 'buf' contains "SEED + offset - 1" */
for (k=0; k<=n; k++)
{
/* obtain "SEED + offset + k" by incrementing: */
for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
{
buf[i]++;
if (buf[i] != 0) break;
}
EVP_Digest(buf,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
/* step 8 */
if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0))
goto err;
if (!BN_lshift(r0,r0,160*k)) goto err;
if (!BN_add(W,W,r0)) goto err;
}
/* more of step 8 */
if (!BN_mask_bits(W,bits-1)) goto err;
if (!BN_copy(X,W)) goto err;
if (!BN_add(X,X,test)) goto err;
/* step 9 */
if (!BN_lshift1(r0,q)) goto err;
if (!BN_mod(c,X,r0,ctx)) goto err;
if (!BN_sub(r0,c,BN_value_one())) goto err;
if (!BN_sub(p,X,r0)) goto err;
/* step 10 */
if (BN_cmp(p,test) >= 0)
{
/* step 11 */
r = BN_is_prime_fasttest(p, DSS_prime_checks, callback, ctx3, cb_arg, 1);
if (r > 0)
goto end; /* found it */
if (r != 0)
goto err;
}
/* step 13 */
counter++;
/* "offset = offset + n + 1" */
/* step 14 */
if (counter >= 4096) break;
}
}
end:
if (callback != NULL) callback(2,1,cb_arg);
/* We now need to generate g */
/* Set r0=(p-1)/q */
if (!BN_sub(test,p,BN_value_one())) goto err;
if (!BN_div(r0,NULL,test,q,ctx)) goto err;
if (!BN_set_word(test,h)) goto err;
if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
for (;;)
{
/* g=test^r0%p */
if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
if (!BN_is_one(g)) break;
if (!BN_add(test,test,BN_value_one())) goto err;
h++;
}
if (callback != NULL) callback(3,1,cb_arg);
ok=1;
err:
if (!ok)
{
if (ret != NULL) DSA_free(ret);
}
else
{
ret->p=BN_dup(p);
ret->q=BN_dup(q);
ret->g=BN_dup(g);
if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
{
ok=0;
goto err;
}
if ((m > 1) && (seed_in != NULL)) memcpy(seed_in,seed,20);
if (counter_ret != NULL) *counter_ret=counter;
if (h_ret != NULL) *h_ret=h;
}
if (ctx != NULL) BN_CTX_free(ctx);
if (ctx2 != NULL)
{
BN_CTX_end(ctx2);
BN_CTX_free(ctx2);
}
if (ctx3 != NULL) BN_CTX_free(ctx3);
if (mont != NULL) BN_MONT_CTX_free(mont);
return(ok?ret:NULL);
}
int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont,
BN_CTX *ctx)
{
int retn=0;
#ifdef MONT_WORD
BIGNUM *n,*r;
BN_ULONG *ap,*np,*rp,n0,v,*nrp;
int al,nl,max,i,x,ri;
BN_CTX_start(ctx);
if ((r = BN_CTX_get(ctx)) == NULL) goto err;
if (!BN_copy(r,a)) goto err;
n= &(mont->N);
ap=a->d;
/* mont->ri is the size of mont->N in bits (rounded up
to the word size) */
al=ri=mont->ri/BN_BITS2;
nl=n->top;
if ((al == 0) || (nl == 0)) { r->top=0; return(1); }
max=(nl+al+1); /* allow for overflow (no?) XXX */
if (bn_wexpand(r,max) == NULL) goto err;
if (bn_wexpand(ret,max) == NULL) goto err;
r->neg=a->neg^n->neg;
np=n->d;
rp=r->d;
nrp= &(r->d[nl]);
/* clear the top words of T */
#if 1
for (i=r->top; i<max; i++) /* memset? XXX */
r->d[i]=0;
#else
memset(&(r->d[r->top]),0,(max-r->top)*sizeof(BN_ULONG));
#endif
r->top=max;
n0=mont->n0;
#ifdef BN_COUNT
fprintf(stderr,"word BN_from_montgomery %d * %d\n",nl,nl);
#endif
for (i=0; i<nl; i++)
{
#ifdef __TANDEM
{
long long t1;
long long t2;
long long t3;
t1 = rp[0] * (n0 & 0177777);
t2 = 037777600000l;
t2 = n0 & t2;
t3 = rp[0] & 0177777;
t2 = (t3 * t2) & BN_MASK2;
t1 = t1 + t2;
v=bn_mul_add_words(rp,np,nl,(BN_ULONG) t1);
}
#else
v=bn_mul_add_words(rp,np,nl,(rp[0]*n0)&BN_MASK2);
#endif
nrp++;
rp++;
if (((nrp[-1]+=v)&BN_MASK2) >= v)
continue;
else
{
if (((++nrp[0])&BN_MASK2) != 0) continue;
if (((++nrp[1])&BN_MASK2) != 0) continue;
for (x=2; (((++nrp[x])&BN_MASK2) == 0); x++) ;
}
}
bn_fix_top(r);
/* mont->ri will be a multiple of the word size */
#if 0
BN_rshift(ret,r,mont->ri);
#else
ret->neg = r->neg;
x=ri;
rp=ret->d;
ap= &(r->d[x]);
if (r->top < x)
al=0;
else
al=r->top-x;
ret->top=al;
al-=4;
for (i=0; i<al; i+=4)
{
BN_ULONG t1,t2,t3,t4;
t1=ap[i+0];
t2=ap[i+1];
t3=ap[i+2];
t4=ap[i+3];
rp[i+0]=t1;
rp[i+1]=t2;
rp[i+2]=t3;
rp[i+3]=t4;
}
al+=4;
for (; i<al; i++)
rp[i]=ap[i];
#endif
#else /* !MONT_WORD */
BIGNUM *t1,*t2;
BN_CTX_start(ctx);
t1 = BN_CTX_get(ctx);
t2 = BN_CTX_get(ctx);
if (t1 == NULL || t2 == NULL) goto err;
if (!BN_copy(t1,a)) goto err;
BN_mask_bits(t1,mont->ri);
if (!BN_mul(t2,t1,&mont->Ni,ctx)) goto err;
BN_mask_bits(t2,mont->ri);
if (!BN_mul(t1,t2,&mont->N,ctx)) goto err;
if (!BN_add(t2,a,t1)) goto err;
if (!BN_rshift(ret,t2,mont->ri)) goto err;
#endif /* MONT_WORD */
if (BN_ucmp(ret, &(mont->N)) >= 0)
{
if (!BN_usub(ret,ret,&(mont->N))) goto err;
}
retn=1;
err:
BN_CTX_end(ctx);
return(retn);
}
static int dsa_builtin_paramgen(DSA *ret, int bits,
unsigned char *seed_in, int seed_len,
int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
{
int ok=0;
unsigned char seed[SHA_DIGEST_LENGTH];
unsigned char md[SHA_DIGEST_LENGTH];
unsigned char buf[SHA_DIGEST_LENGTH],buf2[SHA_DIGEST_LENGTH];
BIGNUM *r0,*W,*X,*c,*test;
BIGNUM *g=NULL,*q=NULL,*p=NULL;
BN_MONT_CTX *mont=NULL;
int k,n=0,i,b,m=0;
int counter=0;
int r=0;
BN_CTX *ctx=NULL;
unsigned int h=2;
if(FIPS_selftest_failed())
{
FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN,
FIPS_R_FIPS_SELFTEST_FAILED);
goto err;
}
if (FIPS_mode() && (bits < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS))
{
DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN, DSA_R_KEY_SIZE_TOO_SMALL);
goto err;
}
if (bits < 512) bits=512;
bits=(bits+63)/64*64;
/* NB: seed_len == 0 is special case: copy generated seed to
* seed_in if it is not NULL.
*/
if (seed_len && (seed_len < 20))
seed_in = NULL; /* seed buffer too small -- ignore */
if (seed_len > 20)
seed_len = 20; /* App. 2.2 of FIPS PUB 186 allows larger SEED,
* but our internal buffers are restricted to 160 bits*/
if ((seed_in != NULL) && (seed_len == 20))
{
memcpy(seed,seed_in,seed_len);
/* set seed_in to NULL to avoid it being copied back */
seed_in = NULL;
}
if ((ctx=BN_CTX_new()) == NULL) goto err;
if ((mont=BN_MONT_CTX_new()) == NULL) goto err;
BN_CTX_start(ctx);
r0 = BN_CTX_get(ctx);
g = BN_CTX_get(ctx);
W = BN_CTX_get(ctx);
q = BN_CTX_get(ctx);
X = BN_CTX_get(ctx);
c = BN_CTX_get(ctx);
p = BN_CTX_get(ctx);
test = BN_CTX_get(ctx);
if (!BN_lshift(test,BN_value_one(),bits-1))
goto err;
for (;;)
{
for (;;) /* find q */
{
int seed_is_random;
/* step 1 */
if(!BN_GENCB_call(cb, 0, m++))
goto err;
if (!seed_len)
{
RAND_pseudo_bytes(seed,SHA_DIGEST_LENGTH);
seed_is_random = 1;
}
else
{
seed_is_random = 0;
seed_len=0; /* use random seed if 'seed_in' turns out to be bad*/
}
memcpy(buf,seed,SHA_DIGEST_LENGTH);
memcpy(buf2,seed,SHA_DIGEST_LENGTH);
/* precompute "SEED + 1" for step 7: */
for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
{
buf[i]++;
if (buf[i] != 0) break;
}
/* step 2 */
EVP_Digest(seed,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
EVP_Digest(buf,SHA_DIGEST_LENGTH,buf2,NULL,HASH, NULL);
for (i=0; i<SHA_DIGEST_LENGTH; i++)
md[i]^=buf2[i];
/* step 3 */
md[0]|=0x80;
md[SHA_DIGEST_LENGTH-1]|=0x01;
if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,q)) goto err;
/* step 4 */
r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
seed_is_random, cb);
if (r > 0)
break;
if (r != 0)
goto err;
/* do a callback call */
/* step 5 */
}
if(!BN_GENCB_call(cb, 2, 0)) goto err;
if(!BN_GENCB_call(cb, 3, 0)) goto err;
/* step 6 */
counter=0;
/* "offset = 2" */
n=(bits-1)/160;
b=(bits-1)-n*160;
for (;;)
{
if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
goto err;
/* step 7 */
BN_zero(W);
/* now 'buf' contains "SEED + offset - 1" */
for (k=0; k<=n; k++)
{
/* obtain "SEED + offset + k" by incrementing: */
for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--)
{
buf[i]++;
if (buf[i] != 0) break;
}
EVP_Digest(buf,SHA_DIGEST_LENGTH,md,NULL,HASH, NULL);
/* step 8 */
if (!BN_bin2bn(md,SHA_DIGEST_LENGTH,r0))
goto err;
if (!BN_lshift(r0,r0,160*k)) goto err;
if (!BN_add(W,W,r0)) goto err;
}
/* more of step 8 */
if (!BN_mask_bits(W,bits-1)) goto err;
if (!BN_copy(X,W)) goto err;
if (!BN_add(X,X,test)) goto err;
/* step 9 */
if (!BN_lshift1(r0,q)) goto err;
if (!BN_mod(c,X,r0,ctx)) goto err;
if (!BN_sub(r0,c,BN_value_one())) goto err;
if (!BN_sub(p,X,r0)) goto err;
/* step 10 */
if (BN_cmp(p,test) >= 0)
{
/* step 11 */
r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
ctx, 1, cb);
if (r > 0)
goto end; /* found it */
if (r != 0)
goto err;
}
/* step 13 */
counter++;
/* "offset = offset + n + 1" */
/* step 14 */
if (counter >= 4096) break;
}
}
end:
if(!BN_GENCB_call(cb, 2, 1))
goto err;
/* We now need to generate g */
/* Set r0=(p-1)/q */
if (!BN_sub(test,p,BN_value_one())) goto err;
if (!BN_div(r0,NULL,test,q,ctx)) goto err;
if (!BN_set_word(test,h)) goto err;
if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
for (;;)
{
/* g=test^r0%p */
if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
if (!BN_is_one(g)) break;
if (!BN_add(test,test,BN_value_one())) goto err;
h++;
}
if(!BN_GENCB_call(cb, 3, 1))
goto err;
ok=1;
err:
if (ok)
{
if(ret->p) BN_free(ret->p);
if(ret->q) BN_free(ret->q);
if(ret->g) BN_free(ret->g);
ret->p=BN_dup(p);
ret->q=BN_dup(q);
ret->g=BN_dup(g);
if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
{
ok=0;
goto err;
}
if (seed_in != NULL) memcpy(seed_in,seed,20);
if (counter_ret != NULL) *counter_ret=counter;
if (h_ret != NULL) *h_ret=h;
}
if(ctx)
{
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (mont != NULL) BN_MONT_CTX_free(mont);
return ok;
}
int dsa_builtin_paramgen2(DSA *ret, size_t L, size_t N,
const EVP_MD *evpmd, const unsigned char *seed_in, size_t seed_len,
unsigned char *seed_out,
int *counter_ret, unsigned long *h_ret, BN_GENCB *cb)
{
int ok=-1;
unsigned char *seed = NULL;
unsigned char md[EVP_MAX_MD_SIZE];
int mdsize;
BIGNUM *r0,*W,*X,*c,*test;
BIGNUM *g=NULL,*q=NULL,*p=NULL;
BN_MONT_CTX *mont=NULL;
int i, k, n=0, m=0, qsize = N >> 3;
int counter=0;
int r=0;
BN_CTX *ctx=NULL;
unsigned int h=2;
#ifdef OPENSSL_FIPS
if(FIPS_selftest_failed())
{
FIPSerr(FIPS_F_DSA_BUILTIN_PARAMGEN2,
FIPS_R_FIPS_SELFTEST_FAILED);
goto err;
}
if (!fips_check_dsa_prng(ret, L, N))
goto err;
#endif
if (evpmd == NULL)
{
if (N == 160)
evpmd = EVP_sha1();
else if (N == 224)
evpmd = EVP_sha224();
else
evpmd = EVP_sha256();
}
mdsize = M_EVP_MD_size(evpmd);
if (seed_len == 0)
seed_len = mdsize;
seed = OPENSSL_malloc(seed_len);
if (!seed)
goto err;
if (seed_in)
memcpy(seed, seed_in, seed_len);
if ((ctx=BN_CTX_new()) == NULL)
goto err;
if ((mont=BN_MONT_CTX_new()) == NULL)
goto err;
BN_CTX_start(ctx);
r0 = BN_CTX_get(ctx);
g = BN_CTX_get(ctx);
W = BN_CTX_get(ctx);
q = BN_CTX_get(ctx);
X = BN_CTX_get(ctx);
c = BN_CTX_get(ctx);
p = BN_CTX_get(ctx);
test = BN_CTX_get(ctx);
if (!BN_lshift(test,BN_value_one(),L-1))
goto err;
for (;;)
{
for (;;) /* find q */
{
unsigned char *pmd;
/* step 1 */
if(!BN_GENCB_call(cb, 0, m++))
goto err;
if (!seed_in)
{
if (RAND_pseudo_bytes(seed, seed_len) < 0)
goto err;
}
/* step 2 */
if (!EVP_Digest(seed, seed_len, md, NULL, evpmd, NULL))
goto err;
/* Take least significant bits of md */
if (mdsize > qsize)
pmd = md + mdsize - qsize;
else
pmd = md;
if (mdsize < qsize)
memset(md + mdsize, 0, qsize - mdsize);
/* step 3 */
pmd[0] |= 0x80;
pmd[qsize-1] |= 0x01;
if (!BN_bin2bn(pmd, qsize, q))
goto err;
/* step 4 */
r = BN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
seed_in ? 1 : 0, cb);
if (r > 0)
break;
if (r != 0)
goto err;
/* Provided seed didn't produce a prime: error */
if (seed_in)
{
ok = 0;
DSAerr(DSA_F_DSA_BUILTIN_PARAMGEN2, DSA_R_Q_NOT_PRIME);
goto err;
}
/* do a callback call */
/* step 5 */
}
/* Copy seed to seed_out before we mess with it */
if (seed_out)
memcpy(seed_out, seed, seed_len);
if(!BN_GENCB_call(cb, 2, 0)) goto err;
if(!BN_GENCB_call(cb, 3, 0)) goto err;
/* step 6 */
counter=0;
/* "offset = 1" */
n=(L-1)/(mdsize << 3);
for (;;)
{
if ((counter != 0) && !BN_GENCB_call(cb, 0, counter))
goto err;
/* step 7 */
BN_zero(W);
/* now 'buf' contains "SEED + offset - 1" */
for (k=0; k<=n; k++)
{
/* obtain "SEED + offset + k" by incrementing: */
for (i = seed_len-1; i >= 0; i--)
{
seed[i]++;
if (seed[i] != 0)
break;
}
if (!EVP_Digest(seed, seed_len, md ,NULL, evpmd,
NULL))
goto err;
/* step 8 */
if (!BN_bin2bn(md, mdsize, r0))
goto err;
if (!BN_lshift(r0,r0,(mdsize << 3)*k)) goto err;
if (!BN_add(W,W,r0)) goto err;
}
/* more of step 8 */
if (!BN_mask_bits(W,L-1)) goto err;
if (!BN_copy(X,W)) goto err;
if (!BN_add(X,X,test)) goto err;
/* step 9 */
if (!BN_lshift1(r0,q)) goto err;
if (!BN_mod(c,X,r0,ctx)) goto err;
if (!BN_sub(r0,c,BN_value_one())) goto err;
if (!BN_sub(p,X,r0)) goto err;
/* step 10 */
if (BN_cmp(p,test) >= 0)
{
/* step 11 */
r = BN_is_prime_fasttest_ex(p, DSS_prime_checks,
ctx, 1, cb);
if (r > 0)
goto end; /* found it */
if (r != 0)
goto err;
}
/* step 13 */
counter++;
/* "offset = offset + n + 1" */
/* step 14 */
if (counter >= 4096) break;
}
}
end:
if(!BN_GENCB_call(cb, 2, 1))
goto err;
/* We now need to generate g */
/* Set r0=(p-1)/q */
if (!BN_sub(test,p,BN_value_one())) goto err;
if (!BN_div(r0,NULL,test,q,ctx)) goto err;
if (!BN_set_word(test,h)) goto err;
if (!BN_MONT_CTX_set(mont,p,ctx)) goto err;
for (;;)
{
/* g=test^r0%p */
if (!BN_mod_exp_mont(g,test,r0,p,ctx,mont)) goto err;
if (!BN_is_one(g)) break;
if (!BN_add(test,test,BN_value_one())) goto err;
h++;
}
if(!BN_GENCB_call(cb, 3, 1))
goto err;
ok=1;
err:
if (ok == 1)
{
if(ret->p) BN_free(ret->p);
if(ret->q) BN_free(ret->q);
if(ret->g) BN_free(ret->g);
ret->p=BN_dup(p);
ret->q=BN_dup(q);
ret->g=BN_dup(g);
if (ret->p == NULL || ret->q == NULL || ret->g == NULL)
{
ok=-1;
goto err;
}
if (counter_ret != NULL) *counter_ret=counter;
if (h_ret != NULL) *h_ret=h;
}
if (seed)
OPENSSL_free(seed);
if(ctx)
{
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (mont != NULL) BN_MONT_CTX_free(mont);
return ok;
}
int xDSA_paramgen(DSA *ret, int bits)
{
int ok=0;
unsigned char seed[SHA_DIGEST_LENGTH];
unsigned char md[SHA_DIGEST_LENGTH];
unsigned char buf[SHA_DIGEST_LENGTH], buf2[SHA_DIGEST_LENGTH];
BIGNUM *r0, *W, *X, *c, *test;
BIGNUM *g=NULL, *q=NULL, *p=NULL;
BN_MONT_CTX *mont=NULL;
int k, n=0, i, b;
int counter=0;
int r=0;
BN_CTX *ctx=NULL;
unsigned int h=2;
if (bits < 512)
bits=512;
bits=(bits+63)/64*64;
if ((ctx=BN_CTX_new()) == NULL)
goto err;
if ((mont=BN_MONT_CTX_new()) == NULL)
goto err;
BN_CTX_start(ctx);
r0 = BN_CTX_get(ctx);
g = BN_CTX_get(ctx);
W = BN_CTX_get(ctx);
q = BN_CTX_get(ctx);
X = BN_CTX_get(ctx);
c = BN_CTX_get(ctx);
p = BN_CTX_get(ctx);
test = BN_CTX_get(ctx);
if (!BN_lshift(test, BN_value_one(), bits-1))
goto err;
for (;;) {
for (;;) /* find q */
{
int seed_is_random;
/* step 1 */
xRAND_bytes(seed, SHA_DIGEST_LENGTH);
seed_is_random = 1;
memcpy(buf, seed, SHA_DIGEST_LENGTH);
memcpy(buf2, seed, SHA_DIGEST_LENGTH);
/* precompute "SEED + 1" for step 7: */
for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--) {
buf[i]++;
if (buf[i] != 0)
break;
}
/* step 2 */
EVP_Digest(seed, SHA_DIGEST_LENGTH, md, NULL, HASH, NULL);
EVP_Digest(buf, SHA_DIGEST_LENGTH, buf2, NULL, HASH, NULL);
for (i=0; i<SHA_DIGEST_LENGTH; i++)
md[i]^=buf2[i];
/* step 3 */
md[0]|=0x80;
md[SHA_DIGEST_LENGTH-1]|=0x01;
if (!BN_bin2bn(md, SHA_DIGEST_LENGTH, q))
goto err;
/* step 4 */
r = xBN_is_prime_fasttest_ex(q, DSS_prime_checks, ctx,
seed_is_random);
if (r > 0)
break;
if (r != 0)
goto err;
/* do a callback call */
/* step 5 */
}
/* step 6 */
counter=0;
/* "offset = 2" */
n=(bits-1)/160;
b=(bits-1)-n*160;
for (;;) {
/* step 7 */
BN_zero(W);
/* now 'buf' contains "SEED + offset - 1" */
for (k=0; k<=n; k++) {
/* obtain "SEED + offset + k" by incrementing: */
for (i=SHA_DIGEST_LENGTH-1; i >= 0; i--) {
buf[i]++;
if (buf[i] != 0)
break;
}
EVP_Digest(buf, SHA_DIGEST_LENGTH, md, NULL, HASH, NULL);
/* step 8 */
if (!BN_bin2bn(md, SHA_DIGEST_LENGTH, r0))
goto err;
if (!BN_lshift(r0, r0, 160*k))
goto err;
if (!BN_add(W, W, r0))
goto err;
}
/* more of step 8 */
if (!BN_mask_bits(W, bits-1))
goto err;
if (!BN_copy(X, W))
goto err;
if (!BN_add(X, X, test))
goto err;
/* step 9 */
if (!BN_lshift1(r0, q))
goto err;
if (!BN_mod(c,X,r0,ctx))
goto err;
if (!BN_sub(r0, c, BN_value_one()))
goto err;
if (!BN_sub(p, X, r0))
goto err;
/* step 10 */
if (BN_cmp(p, test) >= 0) {
/* step 11 */
r = xBN_is_prime_fasttest_ex(p, DSS_prime_checks, ctx, 1);
if (r > 0)
goto end;
/* found it */
if (r != 0)
goto err;
}
/* step 13 */
counter++;
/* "offset = offset + n + 1" */
/* step 14 */
if (counter >= 4096)
break;
}
}
end:
/* We now need to generate g */
/* Set r0=(p-1)/q */
if (!BN_sub(test, p, BN_value_one()))
goto err;
if (!BN_div(r0, NULL, test, q, ctx))
goto err;
if (!BN_set_word(test, h))
goto err;
if (!BN_MONT_CTX_set(mont, p, ctx))
goto err;
for (;;) {
/* g=test^r0%p */
if (!BN_mod_exp_mont(g, test, r0, p, ctx, mont))
goto err;
if (!BN_is_one(g))
break;
if (!BN_add(test, test, BN_value_one()))
goto err;
h++;
}
ok=1;
err:
if (ok) {
if (ret->p)
BN_free(ret->p);
if (ret->q)
BN_free(ret->q);
if (ret->g)
BN_free(ret->g);
ret->p=BN_dup(p);
ret->q=BN_dup(q);
ret->g=BN_dup(g);
if (ret->p == NULL || ret->q == NULL || ret->g == NULL) {
ok=0;
goto err;
}
}
if (ctx) {
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (mont != NULL)
BN_MONT_CTX_free(mont);
return ok;
}
