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heimdal/lib/hcrypto/rsa-ltm.c
Andrew Bartlett 9ffbc17a0f Fix (deliberately) unused variable warning in rsa-ltm.c 
Seen on Ubuntu 18.04 with
gcc version 7.5.0 (Ubuntu 7.5.0-3ubuntu1~18.04)
giving:

rsa-ltm.c: In function ‘ltm_rsa_private_calculate’:
rsa-ltm.c:135:9: error: variable ‘where’ set but not used [-Werror=unused-but-set-variable]
     int where = 0; /* Ignore the set-but-unused warning from this */
         ^~~~~
rsa-ltm.c: In function ‘gen_p’:
rsa-ltm.c:482:9: error: variable ‘where’ set but not used [-Werror=unused-but-set-variable]
     int where = 0; /* Ignore the set-but-unused warning from this */
         ^~~~~

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
2020-05-28 11:10:57 -04:00

637 lines
17 KiB
C
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/*
* Copyright (c) 2006 - 2007, 2010 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <config.h>
#include <roken.h>
#include <krb5-types.h>
#include <assert.h>
#include <rsa.h>
#include "tommath.h"
#define CHECK(f) \
do { if (ret == MP_OKAY && ((ret = f)) != MP_OKAY) { goto out; } } while (0)
#define FIRST(e) do { ret = (e); } while (0)
#define FIRST_ALLOC(e) \
do { where = __LINE__; ret = ((e)) ? MP_OKAY : MP_MEM; } while (0)
#define THEN_MP(e) \
do { where = __LINE__ + 1; if (ret == MP_OKAY) ret = (e); } while (0)
#define THEN_IF_MP(cond, e) \
do { where = __LINE__ + 1; if (ret == MP_OKAY && (cond)) ret = (e); } while (0)
#define THEN_IF_VOID(cond, e) \
do { if (ret == MP_OKAY && (cond)) e; } while (0)
#define THEN_VOID(e) \
do { if (ret == MP_OKAY) e; } while (0)
#define THEN_ALLOC(e) \
do { where = __LINE__ + 1; if (ret == MP_OKAY) ret = ((e)) ? MP_OKAY : MP_MEM; } while (0)
static mp_err
random_num(mp_int *num, size_t len)
{
unsigned char *p;
mp_err ret = MP_MEM;
len = (len + 7) / 8; /* bits to bytes */
if ((p = malloc(len)) && RAND_bytes(p, len) != 1)
ret = MP_ERR;
if (p)
ret = mp_from_ubin(num, p, len);
free(p);
return ret;
}
static mp_err
BN2mpz(mp_int *s, const BIGNUM *bn)
{
size_t len;
mp_err ret = MP_MEM;
void *p;
len = BN_num_bytes(bn);
p = malloc(len);
if (p) {
BN_bn2bin(bn, p);
ret = mp_from_ubin(s, p, len);
}
free(p);
return ret;
}
static mp_err
setup_blind(mp_int *n, mp_int *b, mp_int *bi)
{
mp_err ret;
ret = random_num(b, mp_count_bits(n));
if (ret == MP_OKAY) ret = mp_mod(b, n, b);
if (ret == MP_OKAY) ret = mp_invmod(b, n, bi);
return ret;
}
static mp_err
blind(mp_int *in, mp_int *b, mp_int *e, mp_int *n)
{
mp_err ret;
mp_int t1;
ret = mp_init(&t1);
/* in' = (in * b^e) mod n */
if (ret == MP_OKAY) ret = mp_exptmod(b, e, n, &t1);
if (ret == MP_OKAY) ret = mp_mul(&t1, in, in);
if (ret == MP_OKAY) ret = mp_mod(in, n, in);
mp_clear(&t1);
return ret;
}
static mp_err
unblind(mp_int *out, mp_int *bi, mp_int *n)
{
mp_err ret;
/* out' = (out * 1/b) mod n */
ret = mp_mul(out, bi, out);
if (ret == MP_OKAY) ret = mp_mod(out, n, out);
return ret;
}
static mp_err
ltm_rsa_private_calculate(mp_int * in, mp_int * p, mp_int * q,
mp_int * dmp1, mp_int * dmq1, mp_int * iqmp,
mp_int * out)
{
mp_err ret;
mp_int vp, vq, u;
int where HEIMDAL_UNUSED_ATTRIBUTE = 0;
FIRST(mp_init_multi(&vp, &vq, &u, NULL));
/* vq = c ^ (d mod (q - 1)) mod q */
/* vp = c ^ (d mod (p - 1)) mod p */
THEN_MP(mp_mod(in, p, &u));
THEN_MP(mp_exptmod(&u, dmp1, p, &vp));
THEN_MP(mp_mod(in, q, &u));
THEN_MP(mp_exptmod(&u, dmq1, q, &vq));
/* C2 = 1/q mod p (iqmp) */
/* u = (vp - vq)C2 mod p. */
THEN_MP(mp_sub(&vp, &vq, &u));
THEN_IF_MP(mp_isneg(&u), mp_add(&u, p, &u));
THEN_MP(mp_mul(&u, iqmp, &u));
THEN_MP(mp_mod(&u, p, &u));
/* c ^ d mod n = vq + u q */
THEN_MP(mp_mul(&u, q, &u));
THEN_MP(mp_add(&u, &vq, out));
mp_clear_multi(&vp, &vq, &u, NULL);
return ret;
}
/*
*
*/
static int
ltm_rsa_public_encrypt(int flen, const unsigned char* from,
unsigned char* to, RSA* rsa, int padding)
{
unsigned char *p = NULL, *p0 = NULL;
size_t size, ssize, padlen;
mp_int enc, dec, n, e;
mp_err ret;
int where = __LINE__;
if (padding != RSA_PKCS1_PADDING)
return -1;
FIRST(mp_init_multi(&n, &e, &enc, &dec, NULL));
size = RSA_size(rsa);
THEN_IF_MP((size < RSA_PKCS1_PADDING_SIZE ||
size - RSA_PKCS1_PADDING_SIZE < flen),
MP_ERR);
THEN_MP(BN2mpz(&n, rsa->n));
THEN_MP(BN2mpz(&e, rsa->e));
THEN_IF_MP((mp_cmp_d(&e, 3) == MP_LT), MP_ERR);
THEN_ALLOC((p = p0 = malloc(size - 1)));
if (ret == MP_OKAY) {
padlen = size - flen - 3;
*p++ = 2;
}
THEN_IF_MP((RAND_bytes(p, padlen) != 1), MP_ERR);
if (ret == MP_OKAY) {
while (padlen) {
if (*p == 0)
*p = 1;
padlen--;
p++;
}
*p++ = 0;
memcpy(p, from, flen);
p += flen;
assert((p - p0) == size - 1);
}
THEN_MP(mp_from_ubin(&dec, p0, size - 1));
THEN_MP(mp_exptmod(&dec, &e, &n, &enc));
THEN_VOID(ssize = mp_ubin_size(&enc));
THEN_VOID(assert(size >= ssize));
THEN_MP(mp_to_ubin(&enc, to, SIZE_MAX, NULL));
THEN_VOID(size = ssize);
mp_clear_multi(&dec, &e, &n, NULL);
mp_clear(&enc);
free(p0);
return ret == MP_OKAY ? size : -where;
}
static int
ltm_rsa_public_decrypt(int flen, const unsigned char* from,
unsigned char* to, RSA* rsa, int padding)
{
unsigned char *p;
mp_err ret;
size_t size;
mp_int s, us, n, e;
int where = 0;
if (padding != RSA_PKCS1_PADDING)
return -1;
if (flen > RSA_size(rsa))
return -2;
FIRST(mp_init_multi(&e, &n, &s, &us, NULL));
THEN_MP(BN2mpz(&n, rsa->n));
THEN_MP(BN2mpz(&e, rsa->e));
THEN_MP((mp_cmp_d(&e, 3) == MP_LT) ? MP_ERR : MP_OKAY);
THEN_MP(mp_from_ubin(&s, rk_UNCONST(from), (size_t)flen));
THEN_MP((mp_cmp(&s, &n) >= 0) ? MP_ERR : MP_OKAY);
THEN_MP(mp_exptmod(&s, &e, &n, &us));
THEN_VOID(p = to);
THEN_VOID(size = mp_ubin_size(&us));
THEN_VOID(assert(size <= RSA_size(rsa)));
THEN_MP(mp_to_ubin(&us, p, SIZE_MAX, NULL));
mp_clear_multi(&e, &n, &s, NULL);
mp_clear(&us);
if (ret != MP_OKAY)
return -where;
/* head zero was skipped by mp_to_unsigned_bin */
if (*p == 0)
return -where;
if (*p != 1)
return -(where + 1);
size--; p++;
while (size && *p == 0xff) {
size--; p++;
}
if (size == 0 || *p != 0)
return -(where + 2);
size--; p++;
memmove(to, p, size);
return size;
}
static int
ltm_rsa_private_encrypt(int flen, const unsigned char* from,
unsigned char* to, RSA* rsa, int padding)
{
unsigned char *ptr, *ptr0 = NULL;
mp_err ret;
mp_int in, out, n, e;
mp_int bi, b;
size_t size;
int blinding = (rsa->flags & RSA_FLAG_NO_BLINDING) == 0;
int do_unblind = 0;
int where = 0;
if (padding != RSA_PKCS1_PADDING)
return -1;
FIRST(mp_init_multi(&e, &n, &in, &out, &b, &bi, NULL));
size = RSA_size(rsa);
if (size < RSA_PKCS1_PADDING_SIZE || size - RSA_PKCS1_PADDING_SIZE < flen)
return -2;
THEN_ALLOC((ptr0 = ptr = malloc(size)));
if (ret == MP_OKAY) {
*ptr++ = 0;
*ptr++ = 1;
memset(ptr, 0xff, size - flen - 3);
ptr += size - flen - 3;
*ptr++ = 0;
memcpy(ptr, from, flen);
ptr += flen;
assert((ptr - ptr0) == size);
}
THEN_MP(BN2mpz(&n, rsa->n));
THEN_MP(BN2mpz(&e, rsa->e));
THEN_IF_MP((mp_cmp_d(&e, 3) == MP_LT), MP_ERR);
THEN_MP(mp_from_ubin(&in, ptr0, size));
free(ptr0);
THEN_IF_MP((mp_isneg(&in) || mp_cmp(&in, &n) >= 0), MP_ERR);
if (blinding) {
THEN_MP(setup_blind(&n, &b, &bi));
THEN_MP(blind(&in, &b, &e, &n));
do_unblind = 1;
}
if (ret == MP_OKAY && rsa->p && rsa->q && rsa->dmp1 && rsa->dmq1 &&
rsa->iqmp) {
mp_int p, q, dmp1, dmq1, iqmp;
FIRST(mp_init_multi(&p, &q, &dmp1, &dmq1, &iqmp, NULL));
THEN_MP(BN2mpz(&p, rsa->p));
THEN_MP(BN2mpz(&q, rsa->q));
THEN_MP(BN2mpz(&dmp1, rsa->dmp1));
THEN_MP(BN2mpz(&dmq1, rsa->dmq1));
THEN_MP(BN2mpz(&iqmp, rsa->iqmp));
THEN_MP(ltm_rsa_private_calculate(&in, &p, &q, &dmp1, &dmq1, &iqmp,
&out));
mp_clear_multi(&p, &q, &dmp1, &dmq1, &iqmp, NULL);
if (ret != MP_OKAY) goto out;
} else if (ret == MP_OKAY) {
mp_int d;
THEN_MP(BN2mpz(&d, rsa->d));
THEN_MP(mp_exptmod(&in, &d, &n, &out));
mp_clear(&d);
if (ret != MP_OKAY) goto out;
}
if (do_unblind)
THEN_MP(unblind(&out, &bi, &n));
if (ret == MP_OKAY && size > 0) {
size_t ssize;
ssize = mp_ubin_size(&out);
assert(size >= ssize);
THEN_MP(mp_to_ubin(&out, to, SIZE_MAX, NULL));
size = ssize;
}
out:
mp_clear_multi(&e, &n, &in, &out, &b, &bi, NULL);
return ret == MP_OKAY ? size : -where;
}
static int
ltm_rsa_private_decrypt(int flen, const unsigned char* from,
unsigned char* to, RSA* rsa, int padding)
{
unsigned char *ptr;
size_t size;
mp_err ret;
mp_int in, out, n, e, b, bi;
int blinding = (rsa->flags & RSA_FLAG_NO_BLINDING) == 0;
int do_unblind = 0;
int where = 0;
if (padding != RSA_PKCS1_PADDING)
return -1;
size = RSA_size(rsa);
if (flen > size)
return -2;
FIRST(mp_init_multi(&in, &n, &e, &out, &b, &bi, NULL));
THEN_MP(BN2mpz(&n, rsa->n));
THEN_MP(BN2mpz(&e, rsa->e));
THEN_IF_MP((mp_cmp_d(&e, 3) == MP_LT), MP_ERR);
THEN_MP(mp_from_ubin(&in, rk_UNCONST(from), flen));
THEN_IF_MP((mp_isneg(&in) || mp_cmp(&in, &n) >= 0), MP_ERR);
if (blinding) {
THEN_MP(setup_blind(&n, &b, &bi));
THEN_MP(blind(&in, &b, &e, &n));
do_unblind = 1;
}
if (ret == MP_OKAY && rsa->p && rsa->q && rsa->dmp1 && rsa->dmq1 &&
rsa->iqmp) {
mp_int p, q, dmp1, dmq1, iqmp;
THEN_MP(mp_init_multi(&p, &q, &dmp1, &dmq1, &iqmp, NULL));
THEN_MP(BN2mpz(&p, rsa->p));
THEN_MP(BN2mpz(&q, rsa->q));
THEN_MP(BN2mpz(&dmp1, rsa->dmp1));
THEN_MP(BN2mpz(&dmq1, rsa->dmq1));
THEN_MP(BN2mpz(&iqmp, rsa->iqmp));
THEN_MP(ltm_rsa_private_calculate(&in, &p, &q, &dmp1, &dmq1, &iqmp, &out));
mp_clear_multi(&p, &q, &dmp1, &dmq1, &iqmp, NULL);
if (ret != MP_OKAY) goto out;
} else if (ret == MP_OKAY) {
mp_int d;
THEN_IF_MP((mp_isneg(&in) || mp_cmp(&in, &n) >= 0), MP_ERR);
THEN_MP(BN2mpz(&d, rsa->d));
THEN_MP(mp_exptmod(&in, &d, &n, &out));
mp_clear(&d);
if (ret != MP_OKAY) goto out;
}
if (do_unblind)
THEN_MP(unblind(&out, &bi, &n));
if (ret == MP_OKAY) {
size_t ssize;
ptr = to;
ssize = mp_ubin_size(&out);
assert(size >= ssize);
ret = mp_to_ubin(&out, ptr, SIZE_MAX, NULL);
if (ret != MP_OKAY) goto out;
size = ssize;
/* head zero was skipped by mp_int_to_unsigned */
if (*ptr != 2) {
where = __LINE__;
goto out;
}
size--; ptr++;
while (size && *ptr != 0) {
size--; ptr++;
}
if (size == 0) {
where = __LINE__;
goto out;
}
size--; ptr++;
memmove(to, ptr, size);
}
out:
mp_clear_multi(&e, &n, &in, &out, &b, &bi, NULL);
return (ret == MP_OKAY) ? size : -where;
}
static BIGNUM *
mpz2BN(mp_int *s)
{
size_t size;
BIGNUM *bn;
mp_err ret;
void *p;
size = mp_ubin_size(s);
p = malloc(size);
if (p == NULL && size != 0)
return NULL;
ret = mp_to_ubin(s, p, SIZE_MAX, NULL);
if (ret == MP_OKAY)
bn = BN_bin2bn(p, size, NULL);
free(p);
return (ret == MP_OKAY) ? bn : NULL;
}
enum gen_pq_type { GEN_P, GEN_Q };
static int
gen_p(int bits, enum gen_pq_type pq_type, uint8_t nibble_pair, mp_int *p, mp_int *e, BN_GENCB *cb)
{
unsigned char *buf = NULL;
mp_bool res;
mp_err ret = MP_MEM;
mp_int t1, t2;
size_t len = (bits + 7) / 8;
int trials = mp_prime_rabin_miller_trials(bits);
int counter = 0;
int where HEIMDAL_UNUSED_ATTRIBUTE = 0;
FIRST(mp_init_multi(&t1, &t2, NULL));
if (ret == MP_OKAY && (buf = malloc(len))) do {
BN_GENCB_call(cb, 2, counter++);
/* random bytes */
ret = (RAND_bytes(buf, len) == 1) ? MP_OKAY : MP_ERR;
/* make it odd */
buf[len - 1] |= 1;
/* ensure the high nibble of the product is at least 128 */
if (pq_type == GEN_P)
buf[0] = (nibble_pair & 0xf0) | (buf[0] & 0x0f);
else
buf[0] = ((nibble_pair & 0x0f) << 4) | (buf[0] & 0x0f);
/* load number */
THEN_MP(mp_from_ubin(p, buf, len));
/* test primality; repeat if not */
THEN_MP(mp_prime_is_prime(p, trials, &res));
if (ret == MP_OKAY && res == MP_NO) continue;
/* check gcd(p - 1, e) == 1 */
THEN_MP(mp_sub_d(p, 1, &t1));
THEN_MP(mp_gcd(&t1, e, &t2));
} while (ret == MP_OKAY && mp_cmp_d(&t2, 1) != MP_EQ);
mp_clear_multi(&t1, &t2, NULL);
free(buf);
return ret;
}
static uint8_t pq_high_nibble_pairs[] = {
0x9f, 0xad, 0xae, 0xaf, 0xbc, 0xbd, 0xbe, 0xbf, 0xcb, 0xcc, 0xcd, 0xce, 0xcf,
0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef, 0xf9,
0xfa, 0xfb, 0xfc, 0xfd, 0xfe, 0xff
};
static int
ltm_rsa_generate_key(RSA *rsa, int bits, BIGNUM *e, BN_GENCB *cb)
{
mp_int el, p, q, n, d, dmp1, dmq1, iqmp, t1, t2, t3;
mp_err ret;
uint8_t high_nibbles = 0;
int bitsp;
int where = 0;
if (bits < 789)
return -1;
bitsp = (bits + 1) / 2;
ret = -1;
FIRST(mp_init_multi(&el, &p, &q, &n, &d,
&dmp1, &dmq1, &iqmp,
&t1, &t2, &t3, NULL));
THEN_MP(BN2mpz(&el, e));
/*
* randomly pick a pair of high nibbles for p and q to ensure the product's
* high nibble is at least 128
*/
if (ret == MP_OKAY)
ret = (RAND_bytes(&high_nibbles, 1) == 1) ? MP_OKAY : MP_ERR;
high_nibbles %= sizeof(pq_high_nibble_pairs);
high_nibbles = pq_high_nibble_pairs[high_nibbles];
/* generate p and q so that p != q and bits(pq) ~ bits */
THEN_MP(gen_p(bitsp, GEN_P, high_nibbles, &p, &el, cb));
BN_GENCB_call(cb, 3, 0);
THEN_MP(gen_p(bitsp, GEN_Q, high_nibbles, &q, &el, cb));
/* make p > q */
if (mp_cmp(&p, &q) < 0) {
mp_int c;
c = p;
p = q;
q = c;
}
BN_GENCB_call(cb, 3, 1);
/* calculate n, n = p * q */
THEN_MP(mp_mul(&p, &q, &n));
/* calculate d, d = 1/e mod (p - 1)(q - 1) */
THEN_MP(mp_sub_d(&p, 1, &t1));
THEN_MP(mp_sub_d(&q, 1, &t2));
THEN_MP(mp_mul(&t1, &t2, &t3));
THEN_MP(mp_invmod(&el, &t3, &d));
/* calculate dmp1 dmp1 = d mod (p-1) */
THEN_MP(mp_mod(&d, &t1, &dmp1));
/* calculate dmq1 dmq1 = d mod (q-1) */
THEN_MP(mp_mod(&d, &t2, &dmq1));
/* calculate iqmp iqmp = 1/q mod p */
THEN_MP(mp_invmod(&q, &p, &iqmp));
/* fill in RSA key */
if (ret == MP_OKAY) {
rsa->e = mpz2BN(&el);
rsa->p = mpz2BN(&p);
rsa->q = mpz2BN(&q);
rsa->n = mpz2BN(&n);
rsa->d = mpz2BN(&d);
rsa->dmp1 = mpz2BN(&dmp1);
rsa->dmq1 = mpz2BN(&dmq1);
rsa->iqmp = mpz2BN(&iqmp);
}
mp_clear_multi(&el, &p, &q, &n, &d,
&dmp1, &dmq1, &iqmp,
&t1, &t2, &t3, NULL);
return (ret == MP_OKAY) ? 1 : -where;
}
static int
ltm_rsa_init(RSA *rsa)
{
return 1;
}
static int
ltm_rsa_finish(RSA *rsa)
{
return 1;
}
const RSA_METHOD hc_rsa_ltm_method = {
"hcrypto ltm RSA",
ltm_rsa_public_encrypt,
ltm_rsa_public_decrypt,
ltm_rsa_private_encrypt,
ltm_rsa_private_decrypt,
NULL,
NULL,
ltm_rsa_init,
ltm_rsa_finish,
0,
NULL,
NULL,
NULL,
ltm_rsa_generate_key
};
const RSA_METHOD *
RSA_ltm_method(void)
{
return &hc_rsa_ltm_method;
}
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