From 25505898530a333011f4fd5cbc841ad6b26c089c Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 16:40:04 +0200 Subject: Adding upstream version 1:9.2p1. Signed-off-by: Daniel Baumann --- ssh-rsa.c | 769 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 769 insertions(+) create mode 100644 ssh-rsa.c (limited to 'ssh-rsa.c') 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 + * + * 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 + +#include +#include + +#include +#include + +#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 */ -- cgit v1.2.3