|
- /* $OpenBSD: ssh-rsa.c,v 1.79 2023/03/05 05:34:09 dtucker Exp $ */
- /*
- * Copyright (c) 2000, 2003 Markus Friedl <markus@openbsd.org>
- *
- * Permission to use, copy, modify, and distribute this software for any
- * purpose with or without fee is hereby granted, provided that the above
- * copyright notice and this permission notice appear in all copies.
- *
- * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
- * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
- * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
- * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
- * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
- * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
- * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
- */
-
- #include "includes.h"
-
- #ifdef WITH_OPENSSL
-
- #include <sys/types.h>
-
- #include <openssl/evp.h>
- #include <openssl/err.h>
-
- #include <stdarg.h>
- #include <string.h>
-
- #include "sshbuf.h"
- #include "ssherr.h"
- #define SSHKEY_INTERNAL
- #include "sshkey.h"
- #include "digest.h"
- #include "log.h"
-
- #include "openbsd-compat/openssl-compat.h"
-
- static int openssh_RSA_verify(int, u_char *, size_t, u_char *, size_t, RSA *);
-
- static u_int
- ssh_rsa_size(const struct sshkey *key)
- {
- const BIGNUM *rsa_n;
-
- if (key->rsa == NULL)
- return 0;
- RSA_get0_key(key->rsa, &rsa_n, NULL, NULL);
- return BN_num_bits(rsa_n);
- }
-
- static int
- ssh_rsa_alloc(struct sshkey *k)
- {
- if ((k->rsa = RSA_new()) == NULL)
- return SSH_ERR_ALLOC_FAIL;
- return 0;
- }
-
- static void
- ssh_rsa_cleanup(struct sshkey *k)
- {
- RSA_free(k->rsa);
- k->rsa = NULL;
- }
-
- static int
- ssh_rsa_equal(const struct sshkey *a, const struct sshkey *b)
- {
- const BIGNUM *rsa_e_a, *rsa_n_a;
- const BIGNUM *rsa_e_b, *rsa_n_b;
-
- if (a->rsa == NULL || b->rsa == NULL)
- return 0;
- RSA_get0_key(a->rsa, &rsa_n_a, &rsa_e_a, NULL);
- RSA_get0_key(b->rsa, &rsa_n_b, &rsa_e_b, NULL);
- if (rsa_e_a == NULL || rsa_e_b == NULL)
- return 0;
- if (rsa_n_a == NULL || rsa_n_b == NULL)
- return 0;
- if (BN_cmp(rsa_e_a, rsa_e_b) != 0)
- return 0;
- if (BN_cmp(rsa_n_a, rsa_n_b) != 0)
- return 0;
- return 1;
- }
-
- static int
- ssh_rsa_serialize_public(const struct sshkey *key, struct sshbuf *b,
- enum sshkey_serialize_rep opts)
- {
- int r;
- const BIGNUM *rsa_n, *rsa_e;
-
- if (key->rsa == NULL)
- return SSH_ERR_INVALID_ARGUMENT;
- RSA_get0_key(key->rsa, &rsa_n, &rsa_e, NULL);
- if ((r = sshbuf_put_bignum2(b, rsa_e)) != 0 ||
- (r = sshbuf_put_bignum2(b, rsa_n)) != 0)
- return r;
-
- return 0;
- }
-
- static int
- ssh_rsa_serialize_private(const struct sshkey *key, struct sshbuf *b,
- enum sshkey_serialize_rep opts)
- {
- int r;
- const BIGNUM *rsa_n, *rsa_e, *rsa_d, *rsa_iqmp, *rsa_p, *rsa_q;
-
- RSA_get0_key(key->rsa, &rsa_n, &rsa_e, &rsa_d);
- RSA_get0_factors(key->rsa, &rsa_p, &rsa_q);
- RSA_get0_crt_params(key->rsa, NULL, NULL, &rsa_iqmp);
-
- if (!sshkey_is_cert(key)) {
- /* Note: can't reuse ssh_rsa_serialize_public: e, n vs. n, e */
- if ((r = sshbuf_put_bignum2(b, rsa_n)) != 0 ||
- (r = sshbuf_put_bignum2(b, rsa_e)) != 0)
- return r;
- }
- if ((r = sshbuf_put_bignum2(b, rsa_d)) != 0 ||
- (r = sshbuf_put_bignum2(b, rsa_iqmp)) != 0 ||
- (r = sshbuf_put_bignum2(b, rsa_p)) != 0 ||
- (r = sshbuf_put_bignum2(b, rsa_q)) != 0)
- return r;
-
- return 0;
- }
-
- static int
- ssh_rsa_generate(struct sshkey *k, int bits)
- {
- RSA *private = NULL;
- BIGNUM *f4 = NULL;
- int ret = SSH_ERR_INTERNAL_ERROR;
-
- if (bits < SSH_RSA_MINIMUM_MODULUS_SIZE ||
- bits > SSHBUF_MAX_BIGNUM * 8)
- return SSH_ERR_KEY_LENGTH;
- if ((private = RSA_new()) == NULL || (f4 = BN_new()) == NULL) {
- ret = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
- if (!BN_set_word(f4, RSA_F4) ||
- !RSA_generate_key_ex(private, bits, f4, NULL)) {
- ret = SSH_ERR_LIBCRYPTO_ERROR;
- goto out;
- }
- k->rsa = private;
- private = NULL;
- ret = 0;
- out:
- RSA_free(private);
- BN_free(f4);
- return ret;
- }
-
- static int
- ssh_rsa_copy_public(const struct sshkey *from, struct sshkey *to)
- {
- const BIGNUM *rsa_n, *rsa_e;
- BIGNUM *rsa_n_dup = NULL, *rsa_e_dup = NULL;
- int r = SSH_ERR_INTERNAL_ERROR;
-
- RSA_get0_key(from->rsa, &rsa_n, &rsa_e, NULL);
- if ((rsa_n_dup = BN_dup(rsa_n)) == NULL ||
- (rsa_e_dup = BN_dup(rsa_e)) == NULL) {
- r = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
- if (!RSA_set0_key(to->rsa, rsa_n_dup, rsa_e_dup, NULL)) {
- r = SSH_ERR_LIBCRYPTO_ERROR;
- goto out;
- }
- rsa_n_dup = rsa_e_dup = NULL; /* transferred */
- /* success */
- r = 0;
- out:
- BN_clear_free(rsa_n_dup);
- BN_clear_free(rsa_e_dup);
- return r;
- }
-
- static int
- ssh_rsa_deserialize_public(const char *ktype, struct sshbuf *b,
- struct sshkey *key)
- {
- int ret = SSH_ERR_INTERNAL_ERROR;
- BIGNUM *rsa_n = NULL, *rsa_e = NULL;
-
- if (sshbuf_get_bignum2(b, &rsa_e) != 0 ||
- sshbuf_get_bignum2(b, &rsa_n) != 0) {
- ret = SSH_ERR_INVALID_FORMAT;
- goto out;
- }
- if (!RSA_set0_key(key->rsa, rsa_n, rsa_e, NULL)) {
- ret = SSH_ERR_LIBCRYPTO_ERROR;
- goto out;
- }
- rsa_n = rsa_e = NULL; /* transferred */
- if ((ret = sshkey_check_rsa_length(key, 0)) != 0)
- goto out;
- #ifdef DEBUG_PK
- RSA_print_fp(stderr, key->rsa, 8);
- #endif
- /* success */
- ret = 0;
- out:
- BN_clear_free(rsa_n);
- BN_clear_free(rsa_e);
- return ret;
- }
-
- static int
- ssh_rsa_deserialize_private(const char *ktype, struct sshbuf *b,
- struct sshkey *key)
- {
- int r;
- BIGNUM *rsa_n = NULL, *rsa_e = NULL, *rsa_d = NULL;
- BIGNUM *rsa_iqmp = NULL, *rsa_p = NULL, *rsa_q = NULL;
-
- /* Note: can't reuse ssh_rsa_deserialize_public: e, n vs. n, e */
- if (!sshkey_is_cert(key)) {
- if ((r = sshbuf_get_bignum2(b, &rsa_n)) != 0 ||
- (r = sshbuf_get_bignum2(b, &rsa_e)) != 0)
- goto out;
- if (!RSA_set0_key(key->rsa, rsa_n, rsa_e, NULL)) {
- r = SSH_ERR_LIBCRYPTO_ERROR;
- goto out;
- }
- rsa_n = rsa_e = NULL; /* transferred */
- }
- if ((r = sshbuf_get_bignum2(b, &rsa_d)) != 0 ||
- (r = sshbuf_get_bignum2(b, &rsa_iqmp)) != 0 ||
- (r = sshbuf_get_bignum2(b, &rsa_p)) != 0 ||
- (r = sshbuf_get_bignum2(b, &rsa_q)) != 0)
- goto out;
- if (!RSA_set0_key(key->rsa, NULL, NULL, rsa_d)) {
- r = SSH_ERR_LIBCRYPTO_ERROR;
- goto out;
- }
- rsa_d = NULL; /* transferred */
- if (!RSA_set0_factors(key->rsa, rsa_p, rsa_q)) {
- r = SSH_ERR_LIBCRYPTO_ERROR;
- goto out;
- }
- rsa_p = rsa_q = NULL; /* transferred */
- if ((r = sshkey_check_rsa_length(key, 0)) != 0)
- goto out;
- if ((r = ssh_rsa_complete_crt_parameters(key, rsa_iqmp)) != 0)
- goto out;
- if (RSA_blinding_on(key->rsa, NULL) != 1) {
- r = SSH_ERR_LIBCRYPTO_ERROR;
- goto out;
- }
- /* success */
- r = 0;
- out:
- BN_clear_free(rsa_n);
- BN_clear_free(rsa_e);
- BN_clear_free(rsa_d);
- BN_clear_free(rsa_p);
- BN_clear_free(rsa_q);
- BN_clear_free(rsa_iqmp);
- return r;
- }
-
- static const char *
- rsa_hash_alg_ident(int hash_alg)
- {
- switch (hash_alg) {
- case SSH_DIGEST_SHA1:
- return "ssh-rsa";
- case SSH_DIGEST_SHA256:
- return "rsa-sha2-256";
- case SSH_DIGEST_SHA512:
- return "rsa-sha2-512";
- }
- return NULL;
- }
-
- /*
- * Returns the hash algorithm ID for a given algorithm identifier as used
- * inside the signature blob,
- */
- static int
- rsa_hash_id_from_ident(const char *ident)
- {
- if (strcmp(ident, "ssh-rsa") == 0)
- return SSH_DIGEST_SHA1;
- if (strcmp(ident, "rsa-sha2-256") == 0)
- return SSH_DIGEST_SHA256;
- if (strcmp(ident, "rsa-sha2-512") == 0)
- return SSH_DIGEST_SHA512;
- return -1;
- }
-
- /*
- * Return the hash algorithm ID for the specified key name. This includes
- * all the cases of rsa_hash_id_from_ident() but also the certificate key
- * types.
- */
- static int
- rsa_hash_id_from_keyname(const char *alg)
- {
- int r;
-
- if ((r = rsa_hash_id_from_ident(alg)) != -1)
- return r;
- if (strcmp(alg, "ssh-rsa-cert-v01@openssh.com") == 0)
- return SSH_DIGEST_SHA1;
- if (strcmp(alg, "rsa-sha2-256-cert-v01@openssh.com") == 0)
- return SSH_DIGEST_SHA256;
- if (strcmp(alg, "rsa-sha2-512-cert-v01@openssh.com") == 0)
- return SSH_DIGEST_SHA512;
- return -1;
- }
-
- static int
- rsa_hash_alg_nid(int type)
- {
- switch (type) {
- case SSH_DIGEST_SHA1:
- return NID_sha1;
- case SSH_DIGEST_SHA256:
- return NID_sha256;
- case SSH_DIGEST_SHA512:
- return NID_sha512;
- default:
- return -1;
- }
- }
-
- int
- ssh_rsa_complete_crt_parameters(struct sshkey *key, const BIGNUM *iqmp)
- {
- const BIGNUM *rsa_p, *rsa_q, *rsa_d;
- BIGNUM *aux = NULL, *d_consttime = NULL;
- BIGNUM *rsa_dmq1 = NULL, *rsa_dmp1 = NULL, *rsa_iqmp = NULL;
- BN_CTX *ctx = NULL;
- int r;
-
- if (key == NULL || key->rsa == NULL ||
- sshkey_type_plain(key->type) != KEY_RSA)
- return SSH_ERR_INVALID_ARGUMENT;
-
- RSA_get0_key(key->rsa, NULL, NULL, &rsa_d);
- RSA_get0_factors(key->rsa, &rsa_p, &rsa_q);
-
- if ((ctx = BN_CTX_new()) == NULL)
- return SSH_ERR_ALLOC_FAIL;
- if ((aux = BN_new()) == NULL ||
- (rsa_dmq1 = BN_new()) == NULL ||
- (rsa_dmp1 = BN_new()) == NULL)
- return SSH_ERR_ALLOC_FAIL;
- if ((d_consttime = BN_dup(rsa_d)) == NULL ||
- (rsa_iqmp = BN_dup(iqmp)) == NULL) {
- r = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
- BN_set_flags(aux, BN_FLG_CONSTTIME);
- BN_set_flags(d_consttime, BN_FLG_CONSTTIME);
-
- if ((BN_sub(aux, rsa_q, BN_value_one()) == 0) ||
- (BN_mod(rsa_dmq1, d_consttime, aux, ctx) == 0) ||
- (BN_sub(aux, rsa_p, BN_value_one()) == 0) ||
- (BN_mod(rsa_dmp1, d_consttime, aux, ctx) == 0)) {
- r = SSH_ERR_LIBCRYPTO_ERROR;
- goto out;
- }
- if (!RSA_set0_crt_params(key->rsa, rsa_dmp1, rsa_dmq1, rsa_iqmp)) {
- r = SSH_ERR_LIBCRYPTO_ERROR;
- goto out;
- }
- rsa_dmp1 = rsa_dmq1 = rsa_iqmp = NULL; /* transferred */
- /* success */
- r = 0;
- out:
- BN_clear_free(aux);
- BN_clear_free(d_consttime);
- BN_clear_free(rsa_dmp1);
- BN_clear_free(rsa_dmq1);
- BN_clear_free(rsa_iqmp);
- BN_CTX_free(ctx);
- return r;
- }
-
- /* RSASSA-PKCS1-v1_5 (PKCS #1 v2.0 signature) with SHA1 */
- static int
- ssh_rsa_sign(struct sshkey *key,
- u_char **sigp, size_t *lenp,
- const u_char *data, size_t datalen,
- const char *alg, const char *sk_provider, const char *sk_pin, u_int compat)
- {
- const BIGNUM *rsa_n;
- u_char digest[SSH_DIGEST_MAX_LENGTH], *sig = NULL;
- size_t slen = 0;
- u_int hlen, len;
- int nid, hash_alg, ret = SSH_ERR_INTERNAL_ERROR;
- struct sshbuf *b = NULL;
-
- if (lenp != NULL)
- *lenp = 0;
- if (sigp != NULL)
- *sigp = NULL;
-
- if (alg == NULL || strlen(alg) == 0)
- hash_alg = SSH_DIGEST_SHA1;
- else
- hash_alg = rsa_hash_id_from_keyname(alg);
- if (key == NULL || key->rsa == NULL || hash_alg == -1 ||
- sshkey_type_plain(key->type) != KEY_RSA)
- return SSH_ERR_INVALID_ARGUMENT;
- RSA_get0_key(key->rsa, &rsa_n, NULL, NULL);
- if (BN_num_bits(rsa_n) < SSH_RSA_MINIMUM_MODULUS_SIZE)
- return SSH_ERR_KEY_LENGTH;
- slen = RSA_size(key->rsa);
- if (slen <= 0 || slen > SSHBUF_MAX_BIGNUM)
- return SSH_ERR_INVALID_ARGUMENT;
-
- /* hash the data */
- nid = rsa_hash_alg_nid(hash_alg);
- if ((hlen = ssh_digest_bytes(hash_alg)) == 0)
- return SSH_ERR_INTERNAL_ERROR;
- if ((ret = ssh_digest_memory(hash_alg, data, datalen,
- digest, sizeof(digest))) != 0)
- goto out;
-
- if ((sig = malloc(slen)) == NULL) {
- ret = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
-
- if (RSA_sign(nid, digest, hlen, sig, &len, key->rsa) != 1) {
- ret = SSH_ERR_LIBCRYPTO_ERROR;
- goto out;
- }
- if (len < slen) {
- size_t diff = slen - len;
- memmove(sig + diff, sig, len);
- explicit_bzero(sig, diff);
- } else if (len > slen) {
- ret = SSH_ERR_INTERNAL_ERROR;
- goto out;
- }
- /* encode signature */
- if ((b = sshbuf_new()) == NULL) {
- ret = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
- if ((ret = sshbuf_put_cstring(b, rsa_hash_alg_ident(hash_alg))) != 0 ||
- (ret = sshbuf_put_string(b, sig, slen)) != 0)
- goto out;
- len = sshbuf_len(b);
- if (sigp != NULL) {
- if ((*sigp = malloc(len)) == NULL) {
- ret = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
- memcpy(*sigp, sshbuf_ptr(b), len);
- }
- if (lenp != NULL)
- *lenp = len;
- ret = 0;
- out:
- explicit_bzero(digest, sizeof(digest));
- freezero(sig, slen);
- sshbuf_free(b);
- return ret;
- }
-
- static int
- ssh_rsa_verify(const struct sshkey *key,
- const u_char *sig, size_t siglen,
- const u_char *data, size_t dlen, const char *alg, u_int compat,
- struct sshkey_sig_details **detailsp)
- {
- const BIGNUM *rsa_n;
- char *sigtype = NULL;
- int hash_alg, want_alg, ret = SSH_ERR_INTERNAL_ERROR;
- size_t len = 0, diff, modlen, hlen;
- struct sshbuf *b = NULL;
- u_char digest[SSH_DIGEST_MAX_LENGTH], *osigblob, *sigblob = NULL;
-
- if (key == NULL || key->rsa == NULL ||
- sshkey_type_plain(key->type) != KEY_RSA ||
- sig == NULL || siglen == 0)
- return SSH_ERR_INVALID_ARGUMENT;
- RSA_get0_key(key->rsa, &rsa_n, NULL, NULL);
- if (BN_num_bits(rsa_n) < SSH_RSA_MINIMUM_MODULUS_SIZE)
- return SSH_ERR_KEY_LENGTH;
-
- if ((b = sshbuf_from(sig, siglen)) == NULL)
- return SSH_ERR_ALLOC_FAIL;
- if (sshbuf_get_cstring(b, &sigtype, NULL) != 0) {
- ret = SSH_ERR_INVALID_FORMAT;
- goto out;
- }
- if ((hash_alg = rsa_hash_id_from_ident(sigtype)) == -1) {
- ret = SSH_ERR_KEY_TYPE_MISMATCH;
- goto out;
- }
- /*
- * Allow ssh-rsa-cert-v01 certs to generate SHA2 signatures for
- * legacy reasons, but otherwise the signature type should match.
- */
- if (alg != NULL && strcmp(alg, "ssh-rsa-cert-v01@openssh.com") != 0) {
- if ((want_alg = rsa_hash_id_from_keyname(alg)) == -1) {
- ret = SSH_ERR_INVALID_ARGUMENT;
- goto out;
- }
- if (hash_alg != want_alg) {
- ret = SSH_ERR_SIGNATURE_INVALID;
- goto out;
- }
- }
- if (sshbuf_get_string(b, &sigblob, &len) != 0) {
- ret = SSH_ERR_INVALID_FORMAT;
- goto out;
- }
- if (sshbuf_len(b) != 0) {
- ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
- goto out;
- }
- /* RSA_verify expects a signature of RSA_size */
- modlen = RSA_size(key->rsa);
- if (len > modlen) {
- ret = SSH_ERR_KEY_BITS_MISMATCH;
- goto out;
- } else if (len < modlen) {
- diff = modlen - len;
- osigblob = sigblob;
- if ((sigblob = realloc(sigblob, modlen)) == NULL) {
- sigblob = osigblob; /* put it back for clear/free */
- ret = SSH_ERR_ALLOC_FAIL;
- goto out;
- }
- memmove(sigblob + diff, sigblob, len);
- explicit_bzero(sigblob, diff);
- len = modlen;
- }
- if ((hlen = ssh_digest_bytes(hash_alg)) == 0) {
- ret = SSH_ERR_INTERNAL_ERROR;
- goto out;
- }
- if ((ret = ssh_digest_memory(hash_alg, data, dlen,
- digest, sizeof(digest))) != 0)
- goto out;
-
- ret = openssh_RSA_verify(hash_alg, digest, hlen, sigblob, len,
- key->rsa);
- out:
- freezero(sigblob, len);
- free(sigtype);
- sshbuf_free(b);
- explicit_bzero(digest, sizeof(digest));
- return ret;
- }
-
- /*
- * See:
- * http://www.rsasecurity.com/rsalabs/pkcs/pkcs-1/
- * ftp://ftp.rsasecurity.com/pub/pkcs/pkcs-1/pkcs-1v2-1.asn
- */
-
- /*
- * id-sha1 OBJECT IDENTIFIER ::= { iso(1) identified-organization(3)
- * oiw(14) secsig(3) algorithms(2) 26 }
- */
- static const u_char id_sha1[] = {
- 0x30, 0x21, /* type Sequence, length 0x21 (33) */
- 0x30, 0x09, /* type Sequence, length 0x09 */
- 0x06, 0x05, /* type OID, length 0x05 */
- 0x2b, 0x0e, 0x03, 0x02, 0x1a, /* id-sha1 OID */
- 0x05, 0x00, /* NULL */
- 0x04, 0x14 /* Octet string, length 0x14 (20), followed by sha1 hash */
- };
-
- /*
- * See http://csrc.nist.gov/groups/ST/crypto_apps_infra/csor/algorithms.html
- * id-sha256 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840)
- * organization(1) gov(101) csor(3) nistAlgorithm(4) hashAlgs(2)
- * id-sha256(1) }
- */
- static const u_char id_sha256[] = {
- 0x30, 0x31, /* type Sequence, length 0x31 (49) */
- 0x30, 0x0d, /* type Sequence, length 0x0d (13) */
- 0x06, 0x09, /* type OID, length 0x09 */
- 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, /* id-sha256 */
- 0x05, 0x00, /* NULL */
- 0x04, 0x20 /* Octet string, length 0x20 (32), followed by sha256 hash */
- };
-
- /*
- * See http://csrc.nist.gov/groups/ST/crypto_apps_infra/csor/algorithms.html
- * id-sha512 OBJECT IDENTIFIER ::= { joint-iso-itu-t(2) country(16) us(840)
- * organization(1) gov(101) csor(3) nistAlgorithm(4) hashAlgs(2)
- * id-sha256(3) }
- */
- static const u_char id_sha512[] = {
- 0x30, 0x51, /* type Sequence, length 0x51 (81) */
- 0x30, 0x0d, /* type Sequence, length 0x0d (13) */
- 0x06, 0x09, /* type OID, length 0x09 */
- 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, /* id-sha512 */
- 0x05, 0x00, /* NULL */
- 0x04, 0x40 /* Octet string, length 0x40 (64), followed by sha512 hash */
- };
-
- static int
- rsa_hash_alg_oid(int hash_alg, const u_char **oidp, size_t *oidlenp)
- {
- switch (hash_alg) {
- case SSH_DIGEST_SHA1:
- *oidp = id_sha1;
- *oidlenp = sizeof(id_sha1);
- break;
- case SSH_DIGEST_SHA256:
- *oidp = id_sha256;
- *oidlenp = sizeof(id_sha256);
- break;
- case SSH_DIGEST_SHA512:
- *oidp = id_sha512;
- *oidlenp = sizeof(id_sha512);
- break;
- default:
- return SSH_ERR_INVALID_ARGUMENT;
- }
- return 0;
- }
-
- static int
- openssh_RSA_verify(int hash_alg, u_char *hash, size_t hashlen,
- u_char *sigbuf, size_t siglen, RSA *rsa)
- {
- size_t rsasize = 0, oidlen = 0, hlen = 0;
- int ret, len, oidmatch, hashmatch;
- const u_char *oid = NULL;
- u_char *decrypted = NULL;
-
- if ((ret = rsa_hash_alg_oid(hash_alg, &oid, &oidlen)) != 0)
- return ret;
- ret = SSH_ERR_INTERNAL_ERROR;
- hlen = ssh_digest_bytes(hash_alg);
- if (hashlen != hlen) {
- ret = SSH_ERR_INVALID_ARGUMENT;
- goto done;
- }
- rsasize = RSA_size(rsa);
- if (rsasize <= 0 || rsasize > SSHBUF_MAX_BIGNUM ||
- siglen == 0 || siglen > rsasize) {
- ret = SSH_ERR_INVALID_ARGUMENT;
- goto done;
- }
- if ((decrypted = malloc(rsasize)) == NULL) {
- ret = SSH_ERR_ALLOC_FAIL;
- goto done;
- }
- if ((len = RSA_public_decrypt(siglen, sigbuf, decrypted, rsa,
- RSA_PKCS1_PADDING)) < 0) {
- ret = SSH_ERR_LIBCRYPTO_ERROR;
- goto done;
- }
- if (len < 0 || (size_t)len != hlen + oidlen) {
- ret = SSH_ERR_INVALID_FORMAT;
- goto done;
- }
- oidmatch = timingsafe_bcmp(decrypted, oid, oidlen) == 0;
- hashmatch = timingsafe_bcmp(decrypted + oidlen, hash, hlen) == 0;
- if (!oidmatch || !hashmatch) {
- ret = SSH_ERR_SIGNATURE_INVALID;
- goto done;
- }
- ret = 0;
- done:
- freezero(decrypted, rsasize);
- return ret;
- }
-
- static const struct sshkey_impl_funcs sshkey_rsa_funcs = {
- /* .size = */ ssh_rsa_size,
- /* .alloc = */ ssh_rsa_alloc,
- /* .cleanup = */ ssh_rsa_cleanup,
- /* .equal = */ ssh_rsa_equal,
- /* .ssh_serialize_public = */ ssh_rsa_serialize_public,
- /* .ssh_deserialize_public = */ ssh_rsa_deserialize_public,
- /* .ssh_serialize_private = */ ssh_rsa_serialize_private,
- /* .ssh_deserialize_private = */ ssh_rsa_deserialize_private,
- /* .generate = */ ssh_rsa_generate,
- /* .copy_public = */ ssh_rsa_copy_public,
- /* .sign = */ ssh_rsa_sign,
- /* .verify = */ ssh_rsa_verify,
- };
-
- const struct sshkey_impl sshkey_rsa_impl = {
- /* .name = */ "ssh-rsa",
- /* .shortname = */ "RSA",
- /* .sigalg = */ NULL,
- /* .type = */ KEY_RSA,
- /* .nid = */ 0,
- /* .cert = */ 0,
- /* .sigonly = */ 0,
- /* .keybits = */ 0,
- /* .funcs = */ &sshkey_rsa_funcs,
- };
-
- const struct sshkey_impl sshkey_rsa_cert_impl = {
- /* .name = */ "ssh-rsa-cert-v01@openssh.com",
- /* .shortname = */ "RSA-CERT",
- /* .sigalg = */ NULL,
- /* .type = */ KEY_RSA_CERT,
- /* .nid = */ 0,
- /* .cert = */ 1,
- /* .sigonly = */ 0,
- /* .keybits = */ 0,
- /* .funcs = */ &sshkey_rsa_funcs,
- };
-
- /* SHA2 signature algorithms */
-
- const struct sshkey_impl sshkey_rsa_sha256_impl = {
- /* .name = */ "rsa-sha2-256",
- /* .shortname = */ "RSA",
- /* .sigalg = */ NULL,
- /* .type = */ KEY_RSA,
- /* .nid = */ 0,
- /* .cert = */ 0,
- /* .sigonly = */ 1,
- /* .keybits = */ 0,
- /* .funcs = */ &sshkey_rsa_funcs,
- };
-
- const struct sshkey_impl sshkey_rsa_sha512_impl = {
- /* .name = */ "rsa-sha2-512",
- /* .shortname = */ "RSA",
- /* .sigalg = */ NULL,
- /* .type = */ KEY_RSA,
- /* .nid = */ 0,
- /* .cert = */ 0,
- /* .sigonly = */ 1,
- /* .keybits = */ 0,
- /* .funcs = */ &sshkey_rsa_funcs,
- };
-
- const struct sshkey_impl sshkey_rsa_sha256_cert_impl = {
- /* .name = */ "rsa-sha2-256-cert-v01@openssh.com",
- /* .shortname = */ "RSA-CERT",
- /* .sigalg = */ "rsa-sha2-256",
- /* .type = */ KEY_RSA_CERT,
- /* .nid = */ 0,
- /* .cert = */ 1,
- /* .sigonly = */ 1,
- /* .keybits = */ 0,
- /* .funcs = */ &sshkey_rsa_funcs,
- };
-
- const struct sshkey_impl sshkey_rsa_sha512_cert_impl = {
- /* .name = */ "rsa-sha2-512-cert-v01@openssh.com",
- /* .shortname = */ "RSA-CERT",
- /* .sigalg = */ "rsa-sha2-512",
- /* .type = */ KEY_RSA_CERT,
- /* .nid = */ 0,
- /* .cert = */ 1,
- /* .sigonly = */ 1,
- /* .keybits = */ 0,
- /* .funcs = */ &sshkey_rsa_funcs,
- };
- #endif /* WITH_OPENSSL */
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