diff options
Diffstat (limited to 'src/crypto/rsa/rsa.c')
-rw-r--r-- | src/crypto/rsa/rsa.c | 761 |
1 files changed, 761 insertions, 0 deletions
diff --git a/src/crypto/rsa/rsa.c b/src/crypto/rsa/rsa.c new file mode 100644 index 0000000..cfdd7ff --- /dev/null +++ b/src/crypto/rsa/rsa.c @@ -0,0 +1,761 @@ +/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) + * All rights reserved. + * + * This package is an SSL implementation written + * by Eric Young (eay@cryptsoft.com). + * The implementation was written so as to conform with Netscapes SSL. + * + * This library is free for commercial and non-commercial use as long as + * the following conditions are aheared to. The following conditions + * apply to all code found in this distribution, be it the RC4, RSA, + * lhash, DES, etc., code; not just the SSL code. The SSL documentation + * included with this distribution is covered by the same copyright terms + * except that the holder is Tim Hudson (tjh@cryptsoft.com). + * + * Copyright remains Eric Young's, and as such any Copyright notices in + * the code are not to be removed. + * If this package is used in a product, Eric Young should be given attribution + * as the author of the parts of the library used. + * This can be in the form of a textual message at program startup or + * in documentation (online or textual) provided with the package. + * + * 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 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * "This product includes cryptographic software written by + * Eric Young (eay@cryptsoft.com)" + * The word 'cryptographic' can be left out if the rouines from the library + * being used are not cryptographic related :-). + * 4. If you include any Windows specific code (or a derivative thereof) from + * the apps directory (application code) you must include an acknowledgement: + * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" + * + * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``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 AUTHOR 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. + * + * The licence and distribution terms for any publically available version or + * derivative of this code cannot be changed. i.e. this code cannot simply be + * copied and put under another distribution licence + * [including the GNU Public Licence.] */ + +#include <openssl/rsa.h> + +#include <string.h> + +#include <openssl/bn.h> +#include <openssl/engine.h> +#include <openssl/err.h> +#include <openssl/ex_data.h> +#include <openssl/mem.h> +#include <openssl/obj.h> + +#include "internal.h" + + +extern const RSA_METHOD RSA_default_method; + +RSA *RSA_new(void) { return RSA_new_method(NULL); } + +RSA *RSA_new_method(const ENGINE *engine) { + RSA *rsa = (RSA *)OPENSSL_malloc(sizeof(RSA)); + if (rsa == NULL) { + OPENSSL_PUT_ERROR(RSA, RSA_new_method, ERR_R_MALLOC_FAILURE); + return NULL; + } + + memset(rsa, 0, sizeof(RSA)); + + if (engine) { + rsa->meth = ENGINE_get_RSA_method(engine); + } + + if (rsa->meth == NULL) { + rsa->meth = (RSA_METHOD*) &RSA_default_method; + } + METHOD_ref(rsa->meth); + + rsa->references = 1; + rsa->flags = rsa->meth->flags; + + if (!CRYPTO_new_ex_data(CRYPTO_EX_INDEX_RSA, rsa, &rsa->ex_data)) { + METHOD_unref(rsa->meth); + OPENSSL_free(rsa); + return NULL; + } + + if (rsa->meth->init && !rsa->meth->init(rsa)) { + CRYPTO_free_ex_data(CRYPTO_EX_INDEX_RSA, rsa, &rsa->ex_data); + METHOD_unref(rsa->meth); + OPENSSL_free(rsa); + return NULL; + } + + return rsa; +} + +void RSA_free(RSA *rsa) { + unsigned u; + + if (rsa == NULL) { + return; + } + + if (CRYPTO_add(&rsa->references, -1, CRYPTO_LOCK_RSA) > 0) { + return; + } + + if (rsa->meth->finish) { + rsa->meth->finish(rsa); + } + METHOD_unref(rsa->meth); + + CRYPTO_free_ex_data(CRYPTO_EX_INDEX_DSA, rsa, &rsa->ex_data); + + if (rsa->n != NULL) + BN_clear_free(rsa->n); + if (rsa->e != NULL) + BN_clear_free(rsa->e); + if (rsa->d != NULL) + BN_clear_free(rsa->d); + if (rsa->p != NULL) + BN_clear_free(rsa->p); + if (rsa->q != NULL) + BN_clear_free(rsa->q); + if (rsa->dmp1 != NULL) + BN_clear_free(rsa->dmp1); + if (rsa->dmq1 != NULL) + BN_clear_free(rsa->dmq1); + if (rsa->iqmp != NULL) + BN_clear_free(rsa->iqmp); + for (u = 0; u < rsa->num_blindings; u++) { + BN_BLINDING_free(rsa->blindings[u]); + } + if (rsa->blindings != NULL) + OPENSSL_free(rsa->blindings); + if (rsa->blindings_inuse != NULL) + OPENSSL_free(rsa->blindings_inuse); + OPENSSL_free(rsa); +} + +int RSA_up_ref(RSA *rsa) { + CRYPTO_add(&rsa->references, 1, CRYPTO_LOCK_RSA); + return 1; +} + +int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb) { + if (rsa->meth->keygen) { + return rsa->meth->keygen(rsa, bits, e_value, cb); + } + + return RSA_default_method.keygen(rsa, bits, e_value, cb); +} + +int RSA_encrypt(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out, + const uint8_t *in, size_t in_len, int padding) { + if (rsa->meth->encrypt) { + return rsa->meth->encrypt(rsa, out_len, out, max_out, in, in_len, padding); + } + + return RSA_default_method.encrypt(rsa, out_len, out, max_out, in, in_len, + padding); +} + +int RSA_public_encrypt(int flen, const uint8_t *from, uint8_t *to, RSA *rsa, + int padding) { + size_t out_len; + + if (!RSA_encrypt(rsa, &out_len, to, RSA_size(rsa), from, flen, padding)) { + return -1; + } + + return out_len; +} + +int RSA_sign_raw(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out, + const uint8_t *in, size_t in_len, int padding) { + if (rsa->meth->sign_raw) { + return rsa->meth->sign_raw(rsa, out_len, out, max_out, in, in_len, padding); + } + + return RSA_default_method.sign_raw(rsa, out_len, out, max_out, in, in_len, + padding); +} + +int RSA_private_encrypt(int flen, const uint8_t *from, uint8_t *to, RSA *rsa, + int padding) { + size_t out_len; + + if (!RSA_sign_raw(rsa, &out_len, to, RSA_size(rsa), from, flen, padding)) { + return -1; + } + + return out_len; +} + +int RSA_decrypt(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out, + const uint8_t *in, size_t in_len, int padding) { + if (rsa->meth->decrypt) { + return rsa->meth->decrypt(rsa, out_len, out, max_out, in, in_len, padding); + } + + return RSA_default_method.decrypt(rsa, out_len, out, max_out, in, in_len, + padding); +} + +int RSA_private_decrypt(int flen, const uint8_t *from, uint8_t *to, RSA *rsa, + int padding) { + size_t out_len; + + if (!RSA_decrypt(rsa, &out_len, to, RSA_size(rsa), from, flen, padding)) { + return -1; + } + + return out_len; +} + +int RSA_verify_raw(RSA *rsa, size_t *out_len, uint8_t *out, size_t max_out, + const uint8_t *in, size_t in_len, int padding) { + if (rsa->meth->verify_raw) { + return rsa->meth->verify_raw(rsa, out_len, out, max_out, in, in_len, padding); + } + + return RSA_default_method.verify_raw(rsa, out_len, out, max_out, in, in_len, + padding); +} + +int RSA_public_decrypt(int flen, const uint8_t *from, uint8_t *to, RSA *rsa, + int padding) { + size_t out_len; + + if (!RSA_verify_raw(rsa, &out_len, to, RSA_size(rsa), from, flen, padding)) { + return -1; + } + + return out_len; +} + +unsigned RSA_size(const RSA *rsa) { + if (rsa->meth->size) { + return rsa->meth->size(rsa); + } + + return RSA_default_method.size(rsa); +} + +int RSA_is_opaque(const RSA *rsa) { + return rsa->meth && (rsa->meth->flags & RSA_FLAG_OPAQUE); +} + +int RSA_supports_digest(const RSA *rsa, const EVP_MD *md) { + if (rsa->meth && rsa->meth->supports_digest) { + return rsa->meth->supports_digest(rsa, md); + } + return 1; +} + +int RSA_get_ex_new_index(long argl, void *argp, CRYPTO_EX_new *new_func, + CRYPTO_EX_dup *dup_func, CRYPTO_EX_free *free_func) { + return CRYPTO_get_ex_new_index(CRYPTO_EX_INDEX_RSA, argl, argp, new_func, + dup_func, free_func); +} + +int RSA_set_ex_data(RSA *d, int idx, void *arg) { + return CRYPTO_set_ex_data(&d->ex_data, idx, arg); +} + +void *RSA_get_ex_data(const RSA *d, int idx) { + return CRYPTO_get_ex_data(&d->ex_data, idx); +} + +/* SSL_SIG_LENGTH is the size of an SSL/TLS (prior to TLS 1.2) signature: it's + * the length of an MD5 and SHA1 hash. */ +static const unsigned SSL_SIG_LENGTH = 36; + +/* pkcs1_sig_prefix contains the ASN.1, DER encoded prefix for a hash that is + * to be signed with PKCS#1. */ +struct pkcs1_sig_prefix { + /* nid identifies the hash function. */ + int nid; + /* len is the number of bytes of |bytes| which are valid. */ + uint8_t len; + /* bytes contains the DER bytes. */ + uint8_t bytes[19]; +}; + +/* kPKCS1SigPrefixes contains the ASN.1 prefixes for PKCS#1 signatures with + * different hash functions. */ +static const struct pkcs1_sig_prefix kPKCS1SigPrefixes[] = { + { + NID_md5, + 18, + {0x30, 0x20, 0x30, 0x0c, 0x06, 0x08, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, + 0x02, 0x05, 0x05, 0x00, 0x04, 0x10}, + }, + { + NID_sha1, + 15, + {0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2b, 0x0e, 0x03, 0x02, 0x1a, 0x05, + 0x00, 0x04, 0x14}, + }, + { + NID_sha224, + 19, + {0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, + 0x04, 0x02, 0x04, 0x05, 0x00, 0x04, 0x1c}, + }, + { + NID_sha256, + 19, + {0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, + 0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20}, + }, + { + NID_sha384, + 19, + {0x30, 0x41, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, + 0x04, 0x02, 0x02, 0x05, 0x00, 0x04, 0x30}, + }, + { + NID_sha512, + 19, + {0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, + 0x04, 0x02, 0x03, 0x05, 0x00, 0x04, 0x40}, + }, + { + NID_ripemd160, + 14, + {0x30, 0x20, 0x30, 0x08, 0x06, 0x06, 0x28, 0xcf, 0x06, 0x03, 0x00, 0x31, + 0x04, 0x14}, + }, + { + NID_undef, 0, {0}, + }, +}; + +/* TODO(fork): mostly new code, needs careful review. */ + +/* pkcs1_prefixed_msg builds a PKCS#1, prefixed version of |msg| for the given + * hash function and sets |out_msg| to point to it. On successful return, + * |*out_msg| may be allocated memory and, if so, |*is_alloced| will be 1. */ +static int pkcs1_prefixed_msg(uint8_t **out_msg, size_t *out_msg_len, + int *is_alloced, int hash_nid, const uint8_t *msg, + size_t msg_len) { + unsigned i; + const uint8_t* prefix = NULL; + unsigned prefix_len; + uint8_t *signed_msg; + unsigned signed_msg_len; + + if (hash_nid == NID_md5_sha1) { + /* Special case: SSL signature, just check the length. */ + if (msg_len != SSL_SIG_LENGTH) { + OPENSSL_PUT_ERROR(RSA, RSA_sign, RSA_R_INVALID_MESSAGE_LENGTH); + return 0; + } + + *out_msg = (uint8_t*) msg; + *out_msg_len = SSL_SIG_LENGTH; + *is_alloced = 0; + return 1; + } + + for (i = 0; kPKCS1SigPrefixes[i].nid != NID_undef; i++) { + const struct pkcs1_sig_prefix *sig_prefix = &kPKCS1SigPrefixes[i]; + if (sig_prefix->nid == hash_nid) { + prefix = sig_prefix->bytes; + prefix_len = sig_prefix->len; + break; + } + } + + if (prefix == NULL) { + OPENSSL_PUT_ERROR(RSA, RSA_sign, RSA_R_UNKNOWN_ALGORITHM_TYPE); + return 0; + } + + signed_msg_len = prefix_len + msg_len; + if (signed_msg_len < prefix_len) { + OPENSSL_PUT_ERROR(RSA, RSA_sign, RSA_R_TOO_LONG); + return 0; + } + + signed_msg = OPENSSL_malloc(signed_msg_len); + if (!signed_msg) { + OPENSSL_PUT_ERROR(RSA, RSA_sign, ERR_R_MALLOC_FAILURE); + return 0; + } + + memcpy(signed_msg, prefix, prefix_len); + memcpy(signed_msg + prefix_len, msg, msg_len); + + *out_msg = signed_msg; + *out_msg_len = signed_msg_len; + *is_alloced = 1; + + return 1; +} + +int RSA_sign(int hash_nid, const uint8_t *in, unsigned in_len, uint8_t *out, + unsigned *out_len, RSA *rsa) { + const unsigned rsa_size = RSA_size(rsa); + int ret = 0; + uint8_t *signed_msg; + size_t signed_msg_len; + int signed_msg_is_alloced = 0; + size_t size_t_out_len; + + if (rsa->meth->sign) { + return rsa->meth->sign(hash_nid, in, in_len, out, out_len, rsa); + } + + if (!pkcs1_prefixed_msg(&signed_msg, &signed_msg_len, &signed_msg_is_alloced, + hash_nid, in, in_len)) { + return 0; + } + + if (rsa_size < RSA_PKCS1_PADDING_SIZE || + signed_msg_len > rsa_size - RSA_PKCS1_PADDING_SIZE) { + OPENSSL_PUT_ERROR(RSA, RSA_sign, RSA_R_DIGEST_TOO_BIG_FOR_RSA_KEY); + goto finish; + } + + if (RSA_sign_raw(rsa, &size_t_out_len, out, rsa_size, signed_msg, + signed_msg_len, RSA_PKCS1_PADDING)) { + *out_len = size_t_out_len; + ret = 1; + } + +finish: + if (signed_msg_is_alloced) { + OPENSSL_free(signed_msg); + } + return ret; +} + +int RSA_verify(int hash_nid, const uint8_t *msg, size_t msg_len, + const uint8_t *sig, size_t sig_len, RSA *rsa) { + const size_t rsa_size = RSA_size(rsa); + uint8_t *buf = NULL; + int ret = 0; + uint8_t *signed_msg = NULL; + size_t signed_msg_len, len; + int signed_msg_is_alloced = 0; + + if (rsa->meth->verify) { + return rsa->meth->verify(hash_nid, msg, msg_len, sig, sig_len, rsa); + } + + if (sig_len != rsa_size) { + OPENSSL_PUT_ERROR(RSA, RSA_verify, RSA_R_WRONG_SIGNATURE_LENGTH); + return 0; + } + + if (hash_nid == NID_md5_sha1 && msg_len != SSL_SIG_LENGTH) { + OPENSSL_PUT_ERROR(RSA, RSA_verify, RSA_R_INVALID_MESSAGE_LENGTH); + return 0; + } + + buf = OPENSSL_malloc(rsa_size); + if (!buf) { + OPENSSL_PUT_ERROR(RSA, RSA_verify, ERR_R_MALLOC_FAILURE); + return 0; + } + + if (!RSA_verify_raw(rsa, &len, buf, rsa_size, sig, sig_len, + RSA_PKCS1_PADDING)) { + goto out; + } + + if (!pkcs1_prefixed_msg(&signed_msg, &signed_msg_len, &signed_msg_is_alloced, + hash_nid, msg, msg_len)) { + goto out; + } + + if (len != signed_msg_len || CRYPTO_memcmp(buf, signed_msg, len) != 0) { + OPENSSL_PUT_ERROR(RSA, RSA_verify, RSA_R_BAD_SIGNATURE); + goto out; + } + + ret = 1; + +out: + if (buf != NULL) { + OPENSSL_free(buf); + } + if (signed_msg_is_alloced) { + OPENSSL_free(signed_msg); + } + return ret; +} + +static void bn_free_and_null(BIGNUM **bn) { + if (*bn == NULL) { + return; + } + + BN_free(*bn); + *bn = NULL; +} + +int RSA_check_key(const RSA *key) { + BIGNUM n, pm1, qm1, lcm, gcd, de, dmp1, dmq1, iqmp; + BN_CTX *ctx; + int ok = 0, has_crt_values; + + if (RSA_is_opaque(key)) { + /* Opaque keys can't be checked. */ + return 1; + } + + if ((key->p != NULL) != (key->q != NULL)) { + OPENSSL_PUT_ERROR(RSA, RSA_check_key, RSA_R_ONLY_ONE_OF_P_Q_GIVEN); + return 0; + } + + if (!key->n || !key->e) { + OPENSSL_PUT_ERROR(RSA, RSA_check_key, RSA_R_VALUE_MISSING); + return 0; + } + + if (!key->d || !key->p) { + /* For a public key, or without p and q, there's nothing that can be + * checked. */ + return 1; + } + + ctx = BN_CTX_new(); + if (ctx == NULL) { + OPENSSL_PUT_ERROR(RSA, RSA_check_key, ERR_R_MALLOC_FAILURE); + return 0; + } + + BN_init(&n); + BN_init(&pm1); + BN_init(&qm1); + BN_init(&lcm); + BN_init(&gcd); + BN_init(&de); + BN_init(&dmp1); + BN_init(&dmq1); + BN_init(&iqmp); + + if (/* n = pq */ + !BN_mul(&n, key->p, key->q, ctx) || + /* lcm = lcm(p-1, q-1) */ + !BN_sub(&pm1, key->p, BN_value_one()) || + !BN_sub(&qm1, key->q, BN_value_one()) || + !BN_mul(&lcm, &pm1, &qm1, ctx) || + !BN_gcd(&gcd, &pm1, &qm1, ctx) || + !BN_div(&lcm, NULL, &lcm, &gcd, ctx) || + /* de = d*e mod lcm(p-1, q-1) */ + !BN_mod_mul(&de, key->d, key->e, &lcm, ctx)) { + OPENSSL_PUT_ERROR(RSA, RSA_check_key, ERR_LIB_BN); + goto out; + } + + if (BN_cmp(&n, key->n) != 0) { + OPENSSL_PUT_ERROR(RSA, RSA_check_key, RSA_R_N_NOT_EQUAL_P_Q); + goto out; + } + + if (!BN_is_one(&de)) { + OPENSSL_PUT_ERROR(RSA, RSA_check_key, RSA_R_D_E_NOT_CONGRUENT_TO_1); + goto out; + } + + has_crt_values = key->dmp1 != NULL; + if (has_crt_values != (key->dmq1 != NULL) || + has_crt_values != (key->iqmp != NULL)) { + OPENSSL_PUT_ERROR(RSA, RSA_check_key, RSA_R_INCONSISTENT_SET_OF_CRT_VALUES); + goto out; + } + + if (has_crt_values) { + if (/* dmp1 = d mod (p-1) */ + !BN_mod(&dmp1, key->d, &pm1, ctx) || + /* dmq1 = d mod (q-1) */ + !BN_mod(&dmq1, key->d, &qm1, ctx) || + /* iqmp = q^-1 mod p */ + !BN_mod_inverse(&iqmp, key->q, key->p, ctx)) { + OPENSSL_PUT_ERROR(RSA, RSA_check_key, ERR_LIB_BN); + goto out; + } + + if (BN_cmp(&dmp1, key->dmp1) != 0 || + BN_cmp(&dmq1, key->dmq1) != 0 || + BN_cmp(&iqmp, key->iqmp) != 0) { + OPENSSL_PUT_ERROR(RSA, RSA_check_key, RSA_R_CRT_VALUES_INCORRECT); + goto out; + } + } + + ok = 1; + +out: + BN_free(&n); + BN_free(&pm1); + BN_free(&qm1); + BN_free(&lcm); + BN_free(&gcd); + BN_free(&de); + BN_free(&dmp1); + BN_free(&dmq1); + BN_free(&iqmp); + BN_CTX_free(ctx); + + return ok; +} + +int RSA_recover_crt_params(RSA *rsa) { + BN_CTX *ctx; + BIGNUM *totient, *rem, *multiple, *p_plus_q, *p_minus_q; + int ok = 0; + + if (rsa->n == NULL || rsa->e == NULL || rsa->d == NULL) { + OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, RSA_R_EMPTY_PUBLIC_KEY); + return 0; + } + + if (rsa->p || rsa->q || rsa->dmp1 || rsa->dmq1 || rsa->iqmp) { + OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, + RSA_R_CRT_PARAMS_ALREADY_GIVEN); + return 0; + } + + /* This uses the algorithm from section 9B of the RSA paper: + * http://people.csail.mit.edu/rivest/Rsapaper.pdf */ + + ctx = BN_CTX_new(); + if (ctx == NULL) { + OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, ERR_R_MALLOC_FAILURE); + return 0; + } + + BN_CTX_start(ctx); + totient = BN_CTX_get(ctx); + rem = BN_CTX_get(ctx); + multiple = BN_CTX_get(ctx); + p_plus_q = BN_CTX_get(ctx); + p_minus_q = BN_CTX_get(ctx); + + if (totient == NULL || rem == NULL || multiple == NULL || p_plus_q == NULL || + p_minus_q == NULL) { + OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, ERR_R_MALLOC_FAILURE); + goto err; + } + + /* ed-1 is a small multiple of φ(n). */ + if (!BN_mul(totient, rsa->e, rsa->d, ctx) || + !BN_sub_word(totient, 1) || + /* φ(n) = + * pq - p - q + 1 = + * n - (p + q) + 1 + * + * Thus n is a reasonable estimate for φ(n). So, (ed-1)/n will be very + * close. But, when we calculate the quotient, we'll be truncating it + * because we discard the remainder. Thus (ed-1)/multiple will be >= n, + * which the totient cannot be. So we add one to the estimate. + * + * Consider ed-1 as: + * + * multiple * (n - (p+q) + 1) = + * multiple*n - multiple*(p+q) + multiple + * + * When we divide by n, the first term becomes multiple and, since + * multiple and p+q is tiny compared to n, the second and third terms can + * be ignored. Thus I claim that subtracting one from the estimate is + * sufficient. */ + !BN_div(multiple, NULL, totient, rsa->n, ctx) || + !BN_add_word(multiple, 1) || + !BN_div(totient, rem, totient, multiple, ctx)) { + OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, ERR_R_BN_LIB); + goto err; + } + + if (!BN_is_zero(rem)) { + OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, RSA_R_BAD_RSA_PARAMETERS); + goto err; + } + + rsa->p = BN_new(); + rsa->q = BN_new(); + rsa->dmp1 = BN_new(); + rsa->dmq1 = BN_new(); + rsa->iqmp = BN_new(); + if (rsa->p == NULL || rsa->q == NULL || rsa->dmp1 == NULL || rsa->dmq1 == + NULL || rsa->iqmp == NULL) { + OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, ERR_R_MALLOC_FAILURE); + goto err; + } + + /* φ(n) = n - (p + q) + 1 => + * n - totient + 1 = p + q */ + if (!BN_sub(p_plus_q, rsa->n, totient) || + !BN_add_word(p_plus_q, 1) || + /* p - q = sqrt((p+q)^2 - 4n) */ + !BN_sqr(rem, p_plus_q, ctx) || + !BN_lshift(multiple, rsa->n, 2) || + !BN_sub(rem, rem, multiple) || + !BN_sqrt(p_minus_q, rem, ctx) || + /* q is 1/2 (p+q)-(p-q) */ + !BN_sub(rsa->q, p_plus_q, p_minus_q) || + !BN_rshift1(rsa->q, rsa->q) || + !BN_div(rsa->p, NULL, rsa->n, rsa->q, ctx) || + !BN_mul(multiple, rsa->p, rsa->q, ctx)) { + OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, ERR_R_BN_LIB); + goto err; + } + + if (BN_cmp(multiple, rsa->n) != 0) { + OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, RSA_R_INTERNAL_ERROR); + goto err; + } + + if (!BN_sub(rem, rsa->p, BN_value_one()) || + !BN_mod(rsa->dmp1, rsa->d, rem, ctx) || + !BN_sub(rem, rsa->q, BN_value_one()) || + !BN_mod(rsa->dmq1, rsa->d, rem, ctx) || + !BN_mod_inverse(rsa->iqmp, rsa->q, rsa->p, ctx)) { + OPENSSL_PUT_ERROR(RSA, RSA_recover_crt_params, ERR_R_BN_LIB); + goto err; + } + + ok = 1; + +err: + BN_CTX_end(ctx); + BN_CTX_free(ctx); + if (!ok) { + bn_free_and_null(&rsa->p); + bn_free_and_null(&rsa->q); + bn_free_and_null(&rsa->dmp1); + bn_free_and_null(&rsa->dmq1); + bn_free_and_null(&rsa->iqmp); + } + return ok; +} + +int RSA_private_transform(RSA *rsa, uint8_t *out, const uint8_t *in, + size_t len) { + if (rsa->meth->private_transform) { + return rsa->meth->private_transform(rsa, out, in, len); + } + + return RSA_default_method.private_transform(rsa, out, in, len); +} |