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allow the optional sharing if RSA private keys

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This commit is contained in:
Andreas Steffen
2012-11-22 00:34:42 +01:00
parent 2cb9a014df
commit 48b23d06a8
4 changed files with 227 additions and 112 deletions
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src/libstrongswan/credentials/builder.c
+2
View File
@@ -65,6 +65,8 @@ ENUM(builder_part_names, BUILD_FROM_FILE, BUILD_END,
"BUILD_RSA_EXP2",
"BUILD_RSA_COEFF",
"BUILD_SAFE_PRIMES",
"BUILD_SHARES",
"BUILD_THRESHOLD",
"BUILD_END",
);
src/libstrongswan/credentials/builder.h
+4
View File
@@ -141,6 +141,10 @@ enum builder_part_t {
BUILD_RSA_COEFF,
/** generate (p) and (q) as safe primes */
BUILD_SAFE_PRIMES,
/** number of private key shares */
BUILD_SHARES,
/** minimum number of participating private key shares */
BUILD_THRESHOLD,
/** end of variable argument builder list */
BUILD_END,
};
src/libstrongswan/plugins/gmp/gmp_rsa_private_key.c
+190 -109
View File
@@ -1,7 +1,8 @@
/*
* Copyright (C) 2005-2009 Martin Willi
* Copyright (C) 2005 Jan Hutter
* Hochschule fuer Technik Rapperswil
* Copyright (C) 2005-2009 Martin Willi
* Copyright (C) 2012 Andreas Steffen
* HSR Hochschule fuer Technik Rapperswil
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
@@ -69,9 +70,14 @@ struct private_gmp_rsa_private_key_t {
mpz_t q;
/**
* Private exponent.
* Carmichael function m = lambda(n) = lcm(p-1,q-1).
*/
mpz_t m;
/**
* Private exponent and optional secret sharing polynomial coefficients.
*/
mpz_t d;
mpz_t *d;
/**
* Private exponent 1.
@@ -88,6 +94,21 @@ struct private_gmp_rsa_private_key_t {
*/
mpz_t coeff;
/**
* Total number of private key shares
*/
u_int shares;
/**
* Secret sharing threshold
*/
u_int threshold;
/**
* Optional verification key (threshold > 1).
*/
mpz_t v;
/**
* Keysize in bytes.
*/
@@ -121,22 +142,22 @@ chunk_t gmp_mpz_to_chunk(const mpz_t value)
static void mpz_clear_sensitive(mpz_t z)
{
size_t len = mpz_size(z) * GMP_LIMB_BITS / BITS_PER_BYTE;
u_int8_t *random = alloca(len);
u_int8_t *zeros = alloca(len);
memset(random, 0, len);
memset(zeros, 0, len);
/* overwrite mpz_t with zero bytes before clearing it */
mpz_import(z, len, 1, 1, 1, 0, random);
mpz_import(z, len, 1, 1, 1, 0, zeros);
mpz_clear(z);
}
/**
* Create a mpz prime of at least prime_size
*/
static status_t compute_prime(size_t prime_size, bool safe, mpz_t *prime)
static status_t compute_prime(size_t prime_size, bool safe, mpz_t *p, mpz_t *q)
{
rng_t *rng;
mpz_t q;
chunk_t random_bytes;
int count = 0;
rng = lib->crypto->create_rng(lib->crypto, RNG_TRUE);
if (!rng)
@@ -146,14 +167,16 @@ static status_t compute_prime(size_t prime_size, bool safe, mpz_t *prime)
return FAILED;
}
mpz_init(*prime);
mpz_init(q);
mpz_init(*p);
mpz_init(*q);
do
{
if (!rng->allocate_bytes(rng, prime_size, &random_bytes))
{
DBG1(DBG_LIB, "failed to allocate random prime");
mpz_clear(*p);
mpz_clear(*q);
rng->destroy(rng);
return FAILED;
}
@@ -163,29 +186,33 @@ static status_t compute_prime(size_t prime_size, bool safe, mpz_t *prime)
{
random_bytes.ptr[0] &= 0x7F;
random_bytes.ptr[0] |= 0x60;
mpz_import(q, random_bytes.len, 1, 1, 1, 0, random_bytes.ptr);
mpz_import(*q, random_bytes.len, 1, 1, 1, 0, random_bytes.ptr);
do
{
mpz_nextprime (q, q);
mpz_mul_ui(*prime, q, 2);
mpz_add_ui(*prime, *prime, 1);
count++;
mpz_nextprime (*q, *q);
mpz_mul_ui(*p, *q, 2);
mpz_add_ui(*p, *p, 1);
}
while (mpz_probab_prime_p(*prime, 10) == 0);
while (mpz_probab_prime_p(*p, 10) == 0);
DBG2(DBG_LIB, "safe prime found after %d iterations", count);
}
else
{
random_bytes.ptr[0] |= 0xC0;
mpz_import(*prime, random_bytes.len, 1, 1, 1, 0, random_bytes.ptr);
mpz_nextprime (*prime, *prime);
mpz_import(*p, random_bytes.len, 1, 1, 1, 0, random_bytes.ptr);
mpz_nextprime (*p, *p);
}
chunk_clear(&random_bytes);
}
/* check if the prime isn't too large */
while (((mpz_sizeinbase(*prime, 2) + 7) / 8) > prime_size);
while (((mpz_sizeinbase(*p, 2) + 7) / 8) > prime_size);
rng->destroy(rng);
mpz_clear_sensitive(q);
/* additonally return p-1 */
mpz_sub_ui(*q, *p, 1);
return SUCCESS;
}
@@ -414,7 +441,7 @@ METHOD(private_key_t, get_encoding, bool,
n = gmp_mpz_to_chunk(this->n);
e = gmp_mpz_to_chunk(this->e);
d = gmp_mpz_to_chunk(this->d);
d = gmp_mpz_to_chunk(*this->d);
p = gmp_mpz_to_chunk(this->p);
q = gmp_mpz_to_chunk(this->q);
exp1 = gmp_mpz_to_chunk(this->exp1);
@@ -472,14 +499,24 @@ METHOD(private_key_t, destroy, void,
{
if (ref_put(&this->ref))
{
mpz_clear_sensitive(this->n);
mpz_clear_sensitive(this->e);
int i;
mpz_clear(this->n);
mpz_clear(this->e);
mpz_clear(this->v);
mpz_clear_sensitive(this->p);
mpz_clear_sensitive(this->q);
mpz_clear_sensitive(this->d);
mpz_clear_sensitive(this->m);
mpz_clear_sensitive(this->exp1);
mpz_clear_sensitive(this->exp2);
mpz_clear_sensitive(this->coeff);
for (i = 0; i < this->threshold; i++)
{
mpz_clear_sensitive(*this->d + i);
}
free(this->d);
lib->encoding->clear_cache(lib->encoding, this);
free(this);
}
@@ -490,7 +527,7 @@ METHOD(private_key_t, destroy, void,
*/
static status_t check(private_gmp_rsa_private_key_t *this)
{
mpz_t t, u, q1;
mpz_t u, p1, q1;
status_t status = SUCCESS;
/* PKCS#1 1.5 section 6 requires modulus to have at least 12 octets.
@@ -509,10 +546,14 @@ static status_t check(private_gmp_rsa_private_key_t *this)
return FAILED;
}
mpz_init(t);
mpz_init(u);
mpz_init(p1);
mpz_init(q1);
/* precompute p1 = p-1 and q1 = q-1 */
mpz_sub_ui(p1, this->p, 1);
mpz_sub_ui(q1, this->q, 1);
/* check that n == p * q */
mpz_mul(u, this->p, this->q);
if (mpz_cmp(u, this->n) != 0)
@@ -521,62 +562,54 @@ static status_t check(private_gmp_rsa_private_key_t *this)
}
/* check that e divides neither p-1 nor q-1 */
mpz_sub_ui(t, this->p, 1);
mpz_mod(t, t, this->e);
if (mpz_cmp_ui(t, 0) == 0)
mpz_mod(u, p1, this->e);
if (mpz_cmp_ui(u, 0) == 0)
{
status = FAILED;
}
mpz_sub_ui(t, this->q, 1);
mpz_mod(t, t, this->e);
if (mpz_cmp_ui(t, 0) == 0)
mpz_mod(u, q1, this->e);
if (mpz_cmp_ui(u, 0) == 0)
{
status = FAILED;
}
/* check that d is e^-1 (mod lcm(p-1, q-1)) */
/* see PKCS#1v2, aka RFC 2437, for the "lcm" */
mpz_sub_ui(q1, this->q, 1);
mpz_sub_ui(u, this->p, 1);
mpz_gcd(t, u, q1); /* t := gcd(p-1, q-1) */
mpz_mul(u, u, q1); /* u := (p-1) * (q-1) */
mpz_divexact(u, u, t); /* u := lcm(p-1, q-1) */
mpz_mul(t, this->d, this->e);
mpz_mod(t, t, u);
if (mpz_cmp_ui(t, 1) != 0)
mpz_lcm(this->m, p1, q1);
mpz_mul(u, *this->d, this->e);
mpz_mod(u, u, this->m);
if (mpz_cmp_ui(u, 1) != 0)
{
status = FAILED;
}
/* check that exp1 is d mod (p-1) */
mpz_sub_ui(u, this->p, 1);
mpz_mod(t, this->d, u);
if (mpz_cmp(t, this->exp1) != 0)
mpz_mod(u, *this->d, p1);
if (mpz_cmp(u, this->exp1) != 0)
{
status = FAILED;
}
/* check that exp2 is d mod (q-1) */
mpz_sub_ui(u, this->q, 1);
mpz_mod(t, this->d, u);
if (mpz_cmp(t, this->exp2) != 0)
mpz_mod(u, *this->d, q1);
if (mpz_cmp(u, this->exp2) != 0)
{
status = FAILED;
}
/* check that coeff is (q^-1) mod p */
mpz_mul(t, this->coeff, this->q);
mpz_mod(t, t, this->p);
if (mpz_cmp_ui(t, 1) != 0)
mpz_mul(u, this->coeff, this->q);
mpz_mod(u, u, this->p);
if (mpz_cmp_ui(u, 1) != 0)
{
status = FAILED;
}
mpz_clear_sensitive(t);
mpz_clear_sensitive(u);
mpz_clear_sensitive(p1);
mpz_clear_sensitive(q1);
if (status != SUCCESS)
{
DBG1(DBG_LIB, "key integrity tests failed");
@@ -608,6 +641,7 @@ static private_gmp_rsa_private_key_t *gmp_rsa_private_key_create_empty(void)
.destroy = _destroy,
},
},
.threshold = 1,
.ref = 1,
);
return this;
@@ -618,10 +652,11 @@ static private_gmp_rsa_private_key_t *gmp_rsa_private_key_create_empty(void)
*/
gmp_rsa_private_key_t *gmp_rsa_private_key_gen(key_type_t type, va_list args)
{
mpz_t p, q, n, e, d, exp1, exp2, coeff, m, q1, t;
private_gmp_rsa_private_key_t *this;
u_int key_size = 0;
bool safe_prime = FALSE;
u_int key_size = 0, shares = 0, threshold = 1;
bool safe_prime = FALSE, rng_failed = FALSE, invert_failed = FALSE;
mpz_t p, q, p1, q1, d;
;
while (TRUE)
{
@@ -633,6 +668,12 @@ gmp_rsa_private_key_t *gmp_rsa_private_key_gen(key_type_t type, va_list args)
case BUILD_SAFE_PRIMES:
safe_prime = TRUE;
continue;
case BUILD_SHARES:
shares = va_arg(args, u_int);
continue;
case BUILD_THRESHOLD:
threshold = va_arg(args, u_int);
continue;
case BUILD_END:
break;
default:
@@ -644,75 +685,112 @@ gmp_rsa_private_key_t *gmp_rsa_private_key_gen(key_type_t type, va_list args)
{
return NULL;
}
key_size = key_size / BITS_PER_BYTE;
/* Get values of primes p and q */
if (compute_prime(key_size/2, safe_prime, &p) != SUCCESS)
if (compute_prime(key_size/2, safe_prime, &p, &p1) != SUCCESS)
{
return NULL;
}
if (compute_prime(key_size/2, safe_prime, &q) != SUCCESS)
if (compute_prime(key_size/2, safe_prime, &q, &q1) != SUCCESS)
{
mpz_clear(p);
mpz_clear(p1);
return NULL;
}
mpz_init(t);
mpz_init(n);
mpz_init(d);
mpz_init(exp1);
mpz_init(exp2);
mpz_init(coeff);
/* Swapping Primes so p is larger then q */
if (mpz_cmp(p, q) < 0)
{
mpz_swap(p, q);
mpz_swap(p1, q1);
}
mpz_mul(n, p, q); /* n = p*q */
mpz_init_set_ui(e, PUBLIC_EXPONENT); /* assign public exponent */
mpz_init_set(m, p); /* m = p */
mpz_sub_ui(m, m, 1); /* m = m -1 */
mpz_init_set(q1, q); /* q1 = q */
mpz_sub_ui(q1, q1, 1); /* q1 = q1 -1 */
mpz_gcd(t, m, q1); /* t = gcd(p-1, q-1) */
mpz_mul(m, m, q1); /* m = (p-1)*(q-1) */
mpz_divexact(m, m, t); /* m = m / t */
mpz_gcd(t, m, e); /* t = gcd(m, e) */
mpz_invert(d, e, m); /* e has an inverse mod m */
if (mpz_cmp_ui(d, 0) < 0) /* make sure d is positive */
{
mpz_add(d, d, m);
}
mpz_sub_ui(t, p, 1); /* t = p-1 */
mpz_mod(exp1, d, t); /* exp1 = d mod p-1 */
mpz_sub_ui(t, q, 1); /* t = q-1 */
mpz_mod(exp2, d, t); /* exp2 = d mod q-1 */
mpz_invert(coeff, q, p); /* coeff = q^-1 mod p */
if (mpz_cmp_ui(coeff, 0) < 0) /* make coeff d is positive */
{
mpz_add(coeff, coeff, p);
}
mpz_clear_sensitive(q1);
mpz_clear_sensitive(m);
mpz_clear_sensitive(t);
/* Create and initialize RSA private key object */
this = gmp_rsa_private_key_create_empty();
this->shares = shares;
this->threshold = threshold;
this->d = malloc(threshold * sizeof(mpz_t));
*this->p = *p;
*this->q = *q;
/* apply values */
*(this->p) = *p;
*(this->q) = *q;
*(this->n) = *n;
*(this->e) = *e;
*(this->d) = *d;
*(this->exp1) = *exp1;
*(this->exp2) = *exp2;
*(this->coeff) = *coeff;
mpz_init_set_ui(this->e, PUBLIC_EXPONENT);
mpz_init(this->n);
mpz_init(this->m);
mpz_init(this->exp1);
mpz_init(this->exp2);
mpz_init(this->coeff);
mpz_init(this->v);
mpz_init(d);
mpz_mul(this->n, p, q); /* n = p*q */
mpz_lcm(this->m, p1, q1); /* m = lcm(p-1,q-1) */
mpz_invert(d, this->e, this->m); /* e has an inverse mod m */
mpz_mod(this->exp1, d, p1); /* exp1 = d mod p-1 */
mpz_mod(this->exp2, d, q1); /* exp2 = d mod q-1 */
mpz_invert(this->coeff, q, p); /* coeff = q^-1 mod p */
invert_failed = mpz_cmp_ui(this->m, 0) == 0 ||
mpz_cmp_ui(this->coeff, 0) == 0;
/* store secret exponent d */
(*this->d)[0] = *d;
/* generate and store random coefficients of secret sharing polynomial */
if (threshold > 1)
{
rng_t *rng;
chunk_t random_bytes;
mpz_t u;
int i;
rng = lib->crypto->create_rng(lib->crypto, RNG_TRUE);
mpz_init(u);
for (i = 1; i < threshold; i++)
{
mpz_init(d);
if (!rng->allocate_bytes(rng, key_size, &random_bytes))
{
rng_failed = TRUE;
continue;
}
mpz_import(d, random_bytes.len, 1, 1, 1, 0, random_bytes.ptr);
mpz_mod(d, d, this->m);
(*this->d)[i] = *d;
chunk_clear(&random_bytes);
}
/* generate verification key v as a square number */
do
{
if (!rng->allocate_bytes(rng, key_size, &random_bytes))
{
rng_failed = TRUE;
break;
}
mpz_import(this->v, random_bytes.len, 1, 1, 1, 0, random_bytes.ptr);
mpz_mul(this->v, this->v, this->v);
mpz_mod(this->v, this->v, this->n);
mpz_gcd(u, this->v, this->n);
chunk_free(&random_bytes);
}
while (mpz_cmp_ui(u, 1) != 0);
mpz_clear(u);
rng->destroy(rng);
}
mpz_clear_sensitive(p1);
mpz_clear_sensitive(q1);
if (rng_failed || invert_failed)
{
DBG1(DBG_LIB, "rsa key generation failed");
destroy(this);
return NULL;
}
/* set key size in bytes */
this->k = key_size;
@@ -725,8 +803,8 @@ gmp_rsa_private_key_t *gmp_rsa_private_key_gen(key_type_t type, va_list args)
*/
gmp_rsa_private_key_t *gmp_rsa_private_key_load(key_type_t type, va_list args)
{
chunk_t n, e, d, p, q, exp1, exp2, coeff;
private_gmp_rsa_private_key_t *this;
chunk_t n, e, d, p, q, exp1, exp2, coeff;
n = e = d = p = q = exp1 = exp2 = coeff = chunk_empty;
while (TRUE)
@@ -767,25 +845,28 @@ gmp_rsa_private_key_t *gmp_rsa_private_key_load(key_type_t type, va_list args)
this = gmp_rsa_private_key_create_empty();
this->d = malloc(sizeof(mpz_t));
mpz_init(this->n);
mpz_init(this->e);
mpz_init(*this->d);
mpz_init(this->p);
mpz_init(this->q);
mpz_init(this->d);
mpz_init(this->m);
mpz_init(this->exp1);
mpz_init(this->exp2);
mpz_init(this->coeff);
mpz_init(this->v);
mpz_import(this->n, n.len, 1, 1, 1, 0, n.ptr);
mpz_import(this->e, e.len, 1, 1, 1, 0, e.ptr);
mpz_import(this->d, d.len, 1, 1, 1, 0, d.ptr);
mpz_import(*this->d, d.len, 1, 1, 1, 0, d.ptr);
mpz_import(this->p, p.len, 1, 1, 1, 0, p.ptr);
mpz_import(this->q, q.len, 1, 1, 1, 0, q.ptr);
mpz_import(this->coeff, coeff.len, 1, 1, 1, 0, coeff.ptr);
if (!exp1.len)
{ /* exp1 missing in key, recalculate: exp1 = d mod (p-1) */
mpz_sub_ui(this->exp1, this->p, 1);
mpz_mod(this->exp1, this->d, this->exp1);
mpz_mod(this->exp1, *this->d, this->exp1);
}
else
{
@@ -794,7 +875,7 @@ gmp_rsa_private_key_t *gmp_rsa_private_key_load(key_type_t type, va_list args)
if (!exp2.len)
{ /* exp2 missing in key, recalculate: exp2 = d mod (q-1) */
mpz_sub_ui(this->exp2, this->q, 1);
mpz_mod(this->exp2, this->d, this->exp2);
mpz_mod(this->exp2, *this->d, this->exp2);
}
else
{
src/pki/commands/gen.c
+31 -3
View File
@@ -22,7 +22,7 @@ static int gen()
{
cred_encoding_type_t form = PRIVKEY_ASN1_DER;
key_type_t type = KEY_RSA;
u_int size = 0;
u_int size = 0, shares = 0, threshold = 1;
private_key_t *key;
chunk_t encoding;
bool safe_primes = FALSE;
@@ -64,6 +64,20 @@ static int gen()
case 'p':
safe_primes = TRUE;
continue;
case 'n':
shares = atoi(arg);
if (shares < 2)
{
return command_usage("invalid number of key shares");
}
continue;
case 'l':
threshold = atoi(arg);
if (threshold < 1)
{
return command_usage("invalid key share threshold");
}
continue;
case EOF:
break;
default:
@@ -86,7 +100,18 @@ static int gen()
break;
}
}
if (type == KEY_RSA && safe_primes)
if (type == KEY_RSA && shares)
{
if (threshold > shares)
{
return command_usage("threshold is larger than number of shares");
}
key = lib->creds->create(lib->creds, CRED_PRIVATE_KEY, type,
BUILD_KEY_SIZE, size, BUILD_SAFE_PRIMES,
BUILD_SHARES, shares, BUILD_THRESHOLD, threshold,
BUILD_END);
}
else if (type == KEY_RSA && safe_primes)
{
key = lib->creds->create(lib->creds, CRED_PRIVATE_KEY, type,
BUILD_KEY_SIZE, size, BUILD_SAFE_PRIMES, BUILD_END);
@@ -125,12 +150,15 @@ static void __attribute__ ((constructor))reg()
{
command_register((command_t) {
gen, 'g', "gen", "generate a new private key",
{"[--type rsa|ecdsa] [--size bits] [--safe-primes] [--outform der|pem|pgp]"},
{" [--type rsa|ecdsa] [--size bits] [--safe-primes]",
"[--shares n] [--threshold l] [--outform der|pem|pgp]"},
{
{"help", 'h', 0, "show usage information"},
{"type", 't', 1, "type of key, default: rsa"},
{"size", 's', 1, "keylength in bits, default: rsa 2048, ecdsa 384"},
{"safe-primes", 'p', 0, "generate rsa safe primes"},
{"shares", 'n', 1, "number of private rsa key shares"},
{"threshold", 'l', 1, "minimum number of participating rsa key shares"},
{"outform", 'f', 1, "encoding of generated private key"},
}
});