Attachment 3283 Details for Bug 3005 – Alternative patch modifying only the signature and verification routines

[patch] Alternative patch modifying only the signature and verification routines

file_3005.txt (text/plain), 20.77 KB, created by Jakub Jelen on 2019-05-14 18:53:39 AEST

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Creator: Jakub Jelen

Created: 2019-05-14 18:53:39 AEST

Size: 20.77 KB

patch

obsolete

>From f10751f252f43cea42caee4491f43fb13fdd9f5a Mon Sep 17 00:00:00 2001
>From: Jakub Jelen <jjelen@redhat.com>
>Date: Tue, 14 May 2019 10:45:45 +0200
>Subject: [PATCH] Use high-level OpenSSL API for signatures
>
>---
> digest-openssl.c |  16 ++++
> digest.h         |   6 ++
> ssh-dss.c        |  65 ++++++++++------
> ssh-ecdsa.c      |  69 ++++++++++-------
> ssh-rsa.c        | 193 +++++++++--------------------------------------
> sshkey.c         |  77 +++++++++++++++++++
> sshkey.h         |   4 +
> 7 files changed, 221 insertions(+), 209 deletions(-)
>
>diff --git a/digest-openssl.c b/digest-openssl.c
>index da7ed72bc..6a21d8adb 100644
>--- a/digest-openssl.c
>+++ b/digest-openssl.c
>@@ -63,6 +63,22 @@ const struct ssh_digest digests[] = {
> 	{ -1,			NULL,		0,	NULL },
> };
> 
>+const EVP_MD *
>+ssh_digest_to_md(int digest_type)
>+{
>+	switch (digest_type) {
>+	case SSH_DIGEST_SHA1:
>+		return EVP_sha1();
>+	case SSH_DIGEST_SHA256:
>+		return EVP_sha256();
>+	case SSH_DIGEST_SHA384:
>+		return EVP_sha384();
>+	case SSH_DIGEST_SHA512:
>+		return EVP_sha512();
>+	}
>+	return NULL;
>+}
>+
> static const struct ssh_digest *
> ssh_digest_by_alg(int alg)
> {
>diff --git a/digest.h b/digest.h
>index 274574d0e..c7ceeb36f 100644
>--- a/digest.h
>+++ b/digest.h
>@@ -32,6 +32,12 @@
> struct sshbuf;
> struct ssh_digest_ctx;
> 
>+#ifdef WITH_OPENSSL
>+#include <openssl/evp.h>
>+/* Converts internal digest representation to the OpenSSL one */
>+const EVP_MD *ssh_digest_to_md(int digest_type);
>+#endif
>+
> /* Looks up a digest algorithm by name */
> int ssh_digest_alg_by_name(const char *name);
> 
>diff --git a/ssh-dss.c b/ssh-dss.c
>index a23c383dc..ea45e7275 100644
>--- a/ssh-dss.c
>+++ b/ssh-dss.c
>@@ -52,11 +52,15 @@ int
> ssh_dss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
>     const u_char *data, size_t datalen, u_int compat)
> {
>+	EVP_PKEY *pkey = NULL;
> 	DSA_SIG *sig = NULL;
> 	const BIGNUM *sig_r, *sig_s;
>-	u_char digest[SSH_DIGEST_MAX_LENGTH], sigblob[SIGBLOB_LEN];
>-	size_t rlen, slen, len, dlen = ssh_digest_bytes(SSH_DIGEST_SHA1);
>+	u_char sigblob[SIGBLOB_LEN];
>+	size_t rlen, slen;
>+	int len;
> 	struct sshbuf *b = NULL;
>+	u_char *sigb = NULL;
>+	const u_char *psig = NULL;
> 	int ret = SSH_ERR_INVALID_ARGUMENT;
> 
> 	if (lenp != NULL)
>@@ -67,17 +71,24 @@ ssh_dss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
> 	if (key == NULL || key->dsa == NULL ||
> 	    sshkey_type_plain(key->type) != KEY_DSA)
> 		return SSH_ERR_INVALID_ARGUMENT;
>-	if (dlen == 0)
>-		return SSH_ERR_INTERNAL_ERROR;
> 
>-	if ((ret = ssh_digest_memory(SSH_DIGEST_SHA1, data, datalen,
>-	    digest, sizeof(digest))) != 0)
>+	if ((pkey = EVP_PKEY_new()) == NULL ||
>+	    EVP_PKEY_set1_DSA(pkey, key->dsa) != 1)
>+		return SSH_ERR_ALLOC_FAIL;
>+	ret = sshkey_calculate_signature(pkey, SSH_DIGEST_SHA1, &sigb, &len,
>+	    data, datalen);
>+	EVP_PKEY_free(pkey);
>+	if (ret < 0) {
> 		goto out;
>+	}
> 
>-	if ((sig = DSA_do_sign(digest, dlen, key->dsa)) == NULL) {
>+	psig = sigb;
>+	if ((sig = d2i_DSA_SIG(NULL, &psig, len)) == NULL) {
> 		ret = SSH_ERR_LIBCRYPTO_ERROR;
> 		goto out;
> 	}
>+	free(sigb);
>+	sigb = NULL;
> 
> 	DSA_SIG_get0(sig, &sig_r, &sig_s);
> 	rlen = BN_num_bytes(sig_r);
>@@ -110,7 +121,7 @@ ssh_dss_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
> 		*lenp = len;
> 	ret = 0;
>  out:
>-	explicit_bzero(digest, sizeof(digest));
>+	free(sigb);
> 	DSA_SIG_free(sig);
> 	sshbuf_free(b);
> 	return ret;
>@@ -121,20 +132,20 @@ ssh_dss_verify(const struct sshkey *key,
>     const u_char *signature, size_t signaturelen,
>     const u_char *data, size_t datalen, u_int compat)
> {
>+	EVP_PKEY *pkey = NULL;
> 	DSA_SIG *sig = NULL;
> 	BIGNUM *sig_r = NULL, *sig_s = NULL;
>-	u_char digest[SSH_DIGEST_MAX_LENGTH], *sigblob = NULL;
>-	size_t len, dlen = ssh_digest_bytes(SSH_DIGEST_SHA1);
>+	u_char *sigblob = NULL;
>+	size_t len, slen;
> 	int ret = SSH_ERR_INTERNAL_ERROR;
> 	struct sshbuf *b = NULL;
> 	char *ktype = NULL;
>+	u_char *sigb = NULL, *psig = NULL;
> 
> 	if (key == NULL || key->dsa == NULL ||
> 	    sshkey_type_plain(key->type) != KEY_DSA ||
> 	    signature == NULL || signaturelen == 0)
> 		return SSH_ERR_INVALID_ARGUMENT;
>-	if (dlen == 0)
>-		return SSH_ERR_INTERNAL_ERROR;
> 
> 	/* fetch signature */
> 	if ((b = sshbuf_from(signature, signaturelen)) == NULL)
>@@ -176,25 +187,31 @@ ssh_dss_verify(const struct sshkey *key,
> 	}
> 	sig_r = sig_s = NULL; /* transferred */
> 
>-	/* sha1 the data */
>-	if ((ret = ssh_digest_memory(SSH_DIGEST_SHA1, data, datalen,
>-	    digest, sizeof(digest))) != 0)
>+	if ((slen = i2d_DSA_SIG(sig, NULL)) == 0) {
>+		ret = SSH_ERR_LIBCRYPTO_ERROR;
> 		goto out;
>-
>-	switch (DSA_do_verify(digest, dlen, sig, key->dsa)) {
>-	case 1:
>-		ret = 0;
>-		break;
>-	case 0:
>-		ret = SSH_ERR_SIGNATURE_INVALID;
>+	}
>+	if ((sigb = malloc(slen)) == NULL) {
>+		ret = SSH_ERR_ALLOC_FAIL;
> 		goto out;
>-	default:
>+	}
>+	psig = sigb;
>+	if ((slen = i2d_DSA_SIG(sig, &psig)) == 0) {
> 		ret = SSH_ERR_LIBCRYPTO_ERROR;
> 		goto out;
> 	}
> 
>+	if ((pkey = EVP_PKEY_new()) == NULL ||
>+	    EVP_PKEY_set1_DSA(pkey, key->dsa) != 1) {
>+		ret = SSH_ERR_ALLOC_FAIL;
>+		goto out;
>+	}
>+	ret = sshkey_verify_signature(pkey, SSH_DIGEST_SHA1, data, datalen,
>+	    sigb, slen);
>+	EVP_PKEY_free(pkey);
>+
>  out:
>-	explicit_bzero(digest, sizeof(digest));
>+	free(sigb);
> 	DSA_SIG_free(sig);
> 	BN_clear_free(sig_r);
> 	BN_clear_free(sig_s);
>diff --git a/ssh-ecdsa.c b/ssh-ecdsa.c
>index 599c7199d..b036796e8 100644
>--- a/ssh-ecdsa.c
>+++ b/ssh-ecdsa.c
>@@ -50,11 +50,13 @@ int
> ssh_ecdsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
>     const u_char *data, size_t datalen, u_int compat)
> {
>+	EVP_PKEY *pkey = NULL;
> 	ECDSA_SIG *sig = NULL;
>+	unsigned char *sigb = NULL;
>+	const unsigned char *psig;
> 	const BIGNUM *sig_r, *sig_s;
> 	int hash_alg;
>-	u_char digest[SSH_DIGEST_MAX_LENGTH];
>-	size_t len, dlen;
>+	int len;
> 	struct sshbuf *b = NULL, *bb = NULL;
> 	int ret = SSH_ERR_INTERNAL_ERROR;
> 
>@@ -67,18 +69,24 @@ ssh_ecdsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
> 	    sshkey_type_plain(key->type) != KEY_ECDSA)
> 		return SSH_ERR_INVALID_ARGUMENT;
> 
>-	if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1 ||
>-	    (dlen = ssh_digest_bytes(hash_alg)) == 0)
>+	if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1)
> 		return SSH_ERR_INTERNAL_ERROR;
>-	if ((ret = ssh_digest_memory(hash_alg, data, datalen,
>-	    digest, sizeof(digest))) != 0)
>+
>+	if ((pkey = EVP_PKEY_new()) == NULL ||
>+	    EVP_PKEY_set1_EC_KEY(pkey, key->ecdsa) != 1)
>+		return SSH_ERR_ALLOC_FAIL;
>+	ret = sshkey_calculate_signature(pkey, hash_alg, &sigb, &len, data,
>+	    datalen);
>+	EVP_PKEY_free(pkey);
>+	if (ret < 0) {
> 		goto out;
>+	}
> 
>-	if ((sig = ECDSA_do_sign(digest, dlen, key->ecdsa)) == NULL) {
>+	psig = sigb;
>+	if ((sig = d2i_ECDSA_SIG(NULL, &psig, len)) == NULL) {
> 		ret = SSH_ERR_LIBCRYPTO_ERROR;
> 		goto out;
> 	}
>-
> 	if ((bb = sshbuf_new()) == NULL || (b = sshbuf_new()) == NULL) {
> 		ret = SSH_ERR_ALLOC_FAIL;
> 		goto out;
>@@ -102,7 +110,7 @@ ssh_ecdsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
> 		*lenp = len;
> 	ret = 0;
>  out:
>-	explicit_bzero(digest, sizeof(digest));
>+	free(sigb);
> 	sshbuf_free(b);
> 	sshbuf_free(bb);
> 	ECDSA_SIG_free(sig);
>@@ -115,22 +123,21 @@ ssh_ecdsa_verify(const struct sshkey *key,
>     const u_char *signature, size_t signaturelen,
>     const u_char *data, size_t datalen, u_int compat)
> {
>+	EVP_PKEY *pkey = NULL;
> 	ECDSA_SIG *sig = NULL;
> 	BIGNUM *sig_r = NULL, *sig_s = NULL;
>-	int hash_alg;
>-	u_char digest[SSH_DIGEST_MAX_LENGTH];
>-	size_t dlen;
>+	int hash_alg, len;
> 	int ret = SSH_ERR_INTERNAL_ERROR;
> 	struct sshbuf *b = NULL, *sigbuf = NULL;
> 	char *ktype = NULL;
>+	unsigned char *sigb = NULL, *psig = NULL;
> 
> 	if (key == NULL || key->ecdsa == NULL ||
> 	    sshkey_type_plain(key->type) != KEY_ECDSA ||
> 	    signature == NULL || signaturelen == 0)
> 		return SSH_ERR_INVALID_ARGUMENT;
> 
>-	if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1 ||
>-	    (dlen = ssh_digest_bytes(hash_alg)) == 0)
>+	if ((hash_alg = sshkey_ec_nid_to_hash_alg(key->ecdsa_nid)) == -1)
> 		return SSH_ERR_INTERNAL_ERROR;
> 
> 	/* fetch signature */
>@@ -166,28 +173,36 @@ ssh_ecdsa_verify(const struct sshkey *key,
> 	}
> 	sig_r = sig_s = NULL; /* transferred */
> 
>-	if (sshbuf_len(sigbuf) != 0) {
>-		ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
>+	/* Figure out the length */
>+	if ((len = i2d_ECDSA_SIG(sig, NULL)) == 0) {
>+		ret = SSH_ERR_LIBCRYPTO_ERROR;
>+		goto out;
>+	}
>+	if ((sigb = malloc(len)) == NULL) {
>+		ret = SSH_ERR_ALLOC_FAIL;
> 		goto out;
> 	}
>-	if ((ret = ssh_digest_memory(hash_alg, data, datalen,
>-	    digest, sizeof(digest))) != 0)
>+	psig = sigb;
>+	if ((len = i2d_ECDSA_SIG(sig, &psig)) == 0) {
>+		ret = SSH_ERR_LIBCRYPTO_ERROR;
> 		goto out;
>+	}
> 
>-	switch (ECDSA_do_verify(digest, dlen, sig, key->ecdsa)) {
>-	case 1:
>-		ret = 0;
>-		break;
>-	case 0:
>-		ret = SSH_ERR_SIGNATURE_INVALID;
>+	if (sshbuf_len(sigbuf) != 0) {
>+		ret = SSH_ERR_UNEXPECTED_TRAILING_DATA;
> 		goto out;
>-	default:
>-		ret = SSH_ERR_LIBCRYPTO_ERROR;
>+	}
>+
>+	if ((pkey = EVP_PKEY_new()) == NULL ||
>+	    EVP_PKEY_set1_EC_KEY(pkey, key->ecdsa) != 1) {
>+		ret =  SSH_ERR_ALLOC_FAIL;
> 		goto out;
> 	}
>+	ret = sshkey_verify_signature(pkey, hash_alg, data, datalen, sigb, len);
>+	EVP_PKEY_free(pkey);
> 
>  out:
>-	explicit_bzero(digest, sizeof(digest));
>+	free(sigb);
> 	sshbuf_free(sigbuf);
> 	sshbuf_free(b);
> 	ECDSA_SIG_free(sig);
>diff --git a/ssh-rsa.c b/ssh-rsa.c
>index 9b14f9a9a..8ef3a6aca 100644
>--- a/ssh-rsa.c
>+++ b/ssh-rsa.c
>@@ -37,7 +37,7 @@
> 
> #include "openbsd-compat/openssl-compat.h"
> 
>-static int openssh_RSA_verify(int, u_char *, size_t, u_char *, size_t, RSA *);
>+static int openssh_RSA_verify(int, const u_char *, size_t, u_char *, size_t, EVP_PKEY *);
> 
> static const char *
> rsa_hash_alg_ident(int hash_alg)
>@@ -90,21 +90,6 @@ rsa_hash_id_from_keyname(const char *alg)
> 	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)
> {
>@@ -164,11 +149,10 @@ int
> ssh_rsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
>     const u_char *data, size_t datalen, const char *alg_ident)
> {
>-	const BIGNUM *rsa_n;
>-	u_char digest[SSH_DIGEST_MAX_LENGTH], *sig = NULL;
>-	size_t slen = 0;
>-	u_int dlen, len;
>-	int nid, hash_alg, ret = SSH_ERR_INTERNAL_ERROR;
>+	EVP_PKEY *pkey = NULL;
>+	u_char *sig = NULL;
>+	int len, slen = 0;
>+	int hash_alg, ret = SSH_ERR_INTERNAL_ERROR;
> 	struct sshbuf *b = NULL;
> 
> 	if (lenp != NULL)
>@@ -180,33 +164,24 @@ ssh_rsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
> 		hash_alg = SSH_DIGEST_SHA1;
> 	else
> 		hash_alg = rsa_hash_id_from_keyname(alg_ident);
>+
> 	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 ((dlen = 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 (RSA_bits(key->rsa) < SSH_RSA_MINIMUM_MODULUS_SIZE)
>+		return SSH_ERR_KEY_LENGTH;
> 
>-	if ((sig = malloc(slen)) == NULL) {
>-		ret = SSH_ERR_ALLOC_FAIL;
>+	if ((pkey = EVP_PKEY_new()) == NULL ||
>+	    EVP_PKEY_set1_RSA(pkey, key->rsa) != 1)
>+		return SSH_ERR_ALLOC_FAIL;
>+	ret = sshkey_calculate_signature(pkey, hash_alg, &sig, &len, data,
>+	    datalen);
>+	EVP_PKEY_free(pkey);
>+	if (ret < 0) {
> 		goto out;
> 	}
> 
>-	if (RSA_sign(nid, digest, dlen, 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);
>@@ -215,6 +190,7 @@ ssh_rsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
> 		ret = SSH_ERR_INTERNAL_ERROR;
> 		goto out;
> 	}
>+
> 	/* encode signature */
> 	if ((b = sshbuf_new()) == NULL) {
> 		ret = SSH_ERR_ALLOC_FAIL;
>@@ -235,7 +211,6 @@ ssh_rsa_sign(const struct sshkey *key, u_char **sigp, size_t *lenp,
> 		*lenp = len;
> 	ret = 0;
>  out:
>-	explicit_bzero(digest, sizeof(digest));
> 	freezero(sig, slen);
> 	sshbuf_free(b);
> 	return ret;
>@@ -246,10 +221,10 @@ ssh_rsa_verify(const struct sshkey *key,
>     const u_char *sig, size_t siglen, const u_char *data, size_t datalen,
>     const char *alg)
> {
>-	const BIGNUM *rsa_n;
>+	EVP_PKEY *pkey = NULL;
> 	char *sigtype = NULL;
> 	int hash_alg, want_alg, ret = SSH_ERR_INTERNAL_ERROR;
>-	size_t len = 0, diff, modlen, dlen;
>+	size_t len = 0, diff, modlen;
> 	struct sshbuf *b = NULL;
> 	u_char digest[SSH_DIGEST_MAX_LENGTH], *osigblob, *sigblob = NULL;
> 
>@@ -257,8 +232,7 @@ ssh_rsa_verify(const struct sshkey *key,
> 	    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)
>+	if (RSA_bits(key->rsa) < SSH_RSA_MINIMUM_MODULUS_SIZE)
> 		return SSH_ERR_KEY_LENGTH;
> 
> 	if ((b = sshbuf_from(sig, siglen)) == NULL)
>@@ -310,16 +284,15 @@ ssh_rsa_verify(const struct sshkey *key,
> 		explicit_bzero(sigblob, diff);
> 		len = modlen;
> 	}
>-	if ((dlen = ssh_digest_bytes(hash_alg)) == 0) {
>-		ret = SSH_ERR_INTERNAL_ERROR;
>+
>+	if ((pkey = EVP_PKEY_new()) == NULL ||
>+	    EVP_PKEY_set1_RSA(pkey, key->rsa) != 1) {
>+		ret = SSH_ERR_ALLOC_FAIL;
> 		goto out;
> 	}
>-	if ((ret = ssh_digest_memory(hash_alg, data, datalen,
>-	    digest, sizeof(digest))) != 0)
>-		goto out;
>+	ret = openssh_RSA_verify(hash_alg, data, datalen, sigblob, len, pkey);
>+	EVP_PKEY_free(pkey);
> 
>-	ret = openssh_RSA_verify(hash_alg, digest, dlen, sigblob, len,
>-	    key->rsa);
>  out:
> 	freezero(sigblob, len);
> 	free(sigtype);
>@@ -328,122 +301,26 @@ ssh_rsa_verify(const struct sshkey *key,
> 	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)
>+openssh_RSA_verify(int hash_alg, const u_char *data, size_t datalen,
>+    u_char *sigbuf, size_t siglen, EVP_PKEY *pkey)
> {
>-	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;
>-}
>+	size_t rsasize = 0;
>+	const RSA *rsa;
>+	int ret;
> 
>-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;
>-	}
>+	rsa = EVP_PKEY_get0_RSA(pkey);
> 	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;
>+
>+	ret = sshkey_verify_signature(pkey, hash_alg, data, datalen,
>+	    sigbuf, siglen);
>+
> done:
>-	freezero(decrypted, rsasize);
> 	return ret;
> }
> #endif /* WITH_OPENSSL */
>diff --git a/sshkey.c b/sshkey.c
>index ad1957762..b95ed0b10 100644
>--- a/sshkey.c
>+++ b/sshkey.c
>@@ -358,6 +358,83 @@ sshkey_type_plain(int type)
> }
> 
> #ifdef WITH_OPENSSL
>+int
>+sshkey_calculate_signature(EVP_PKEY *pkey, int hash_alg, u_char **sigp,
>+    int *lenp, const u_char *data, size_t datalen)
>+{
>+	EVP_MD_CTX *ctx = NULL;
>+	u_char *sig = NULL;
>+	int ret, slen, len;
>+
>+	if (sigp == NULL || lenp == NULL) {
>+		return SSH_ERR_INVALID_ARGUMENT;
>+	}
>+
>+	slen = EVP_PKEY_size(pkey);
>+	if (slen <= 0 || slen > SSHBUF_MAX_BIGNUM)
>+		return SSH_ERR_INVALID_ARGUMENT;
>+
>+	len = slen;
>+	if ((sig = malloc(slen)) == NULL) {
>+		return SSH_ERR_ALLOC_FAIL;
>+	}
>+
>+	if ((ctx = EVP_MD_CTX_new()) == NULL) {
>+		ret = SSH_ERR_ALLOC_FAIL;
>+		goto error;
>+	}
>+	if (EVP_SignInit_ex(ctx, ssh_digest_to_md(hash_alg), NULL) <= 0 ||
>+	    EVP_SignUpdate(ctx, data, datalen) <= 0 ||
>+	    EVP_SignFinal(ctx, sig, &len, pkey) <= 0) {
>+		ret = SSH_ERR_LIBCRYPTO_ERROR;
>+		goto error;
>+	}
>+
>+	*sigp = sig;
>+	*lenp = len;
>+	/* Now owned by the caller */
>+	sig = NULL;
>+	ret = 0;
>+
>+error:
>+	EVP_MD_CTX_free(ctx);
>+	free(sig);
>+	return ret;
>+}
>+
>+int
>+sshkey_verify_signature(EVP_PKEY *pkey, int hash_alg, const u_char *data,
>+    size_t datalen, u_char *sigbuf, int siglen)
>+{
>+	EVP_MD_CTX *ctx = NULL;
>+	int ret;
>+
>+	if ((ctx = EVP_MD_CTX_new()) == NULL) {
>+		return SSH_ERR_ALLOC_FAIL;
>+	}
>+	if (EVP_VerifyInit_ex(ctx, ssh_digest_to_md(hash_alg), NULL) <= 0 ||
>+	    EVP_VerifyUpdate(ctx, data, datalen) <= 0) {
>+		ret = SSH_ERR_LIBCRYPTO_ERROR;
>+		goto done;
>+	}
>+	ret = EVP_VerifyFinal(ctx, sigbuf, siglen, pkey);
>+	switch (ret) {
>+	case 1:
>+		ret = 0;
>+		break;
>+	case 0:
>+		ret = SSH_ERR_SIGNATURE_INVALID;
>+		break;
>+	default:
>+		ret = SSH_ERR_LIBCRYPTO_ERROR;
>+		break;
>+	}
>+
>+done:
>+	EVP_MD_CTX_free(ctx);
>+	return ret;
>+}
>+
> /* XXX: these are really begging for a table-driven approach */
> int
> sshkey_curve_name_to_nid(const char *name)
>diff --git a/sshkey.h b/sshkey.h
>index a91e60436..270901a87 100644
>--- a/sshkey.h
>+++ b/sshkey.h
>@@ -179,6 +179,10 @@ const char	*sshkey_ssh_name(const struct sshkey *);
> const char	*sshkey_ssh_name_plain(const struct sshkey *);
> int		 sshkey_names_valid2(const char *, int);
> char		*sshkey_alg_list(int, int, int, char);
>+int		 sshkey_calculate_signature(EVP_PKEY*, int, u_char **,
>+    int *, const u_char *, size_t);
>+int		 sshkey_verify_signature(EVP_PKEY *, int, const u_char *,
>+    size_t, u_char *, int);
> 
> int	 sshkey_from_blob(const u_char *, size_t, struct sshkey **);
> int	 sshkey_fromb(struct sshbuf *, struct sshkey **);

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Attachments on bug 3005: 3277 | 3283