Adding upstream version 1:9.2p1.upstream/1%9.2p1upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 769 insertions, 0 deletions

diff --git a/ssh-rsa.c b/ssh-rsa.c
new file mode 100644
index 0000000..6516ddc
--- /dev/null
+++ b/ssh-rsa.c
@@ -0,0 +1,769 @@
+/* $OpenBSD: ssh-rsa.c,v 1.78 2022/10/28 02:47:04 djm 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 "compat.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 */