From 999ae6be3243c7b4a815247199447b53c39a3d65 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Mon, 6 May 2024 03:26:58 +0200 Subject: Adding upstream version 1:7.9p1. Signed-off-by: Daniel Baumann --- ssh-rsa.c | 449 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 449 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..9b14f9a --- /dev/null +++ b/ssh-rsa.c @@ -0,0 +1,449 @@ +/* $OpenBSD: ssh-rsa.c,v 1.67 2018/07/03 11:39:54 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 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 */ +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; + struct sshbuf *b = NULL; + + if (lenp != NULL) + *lenp = 0; + if (sigp != NULL) + *sigp = NULL; + + if (alg_ident == NULL || strlen(alg_ident) == 0) + 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 ((sig = malloc(slen)) == NULL) { + ret = SSH_ERR_ALLOC_FAIL; + 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); + 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; +} + +int +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; + char *sigtype = NULL; + int hash_alg, want_alg, ret = SSH_ERR_INTERNAL_ERROR; + size_t len = 0, diff, modlen, dlen; + 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 ((dlen = ssh_digest_bytes(hash_alg)) == 0) { + ret = SSH_ERR_INTERNAL_ERROR; + goto out; + } + if ((ret = ssh_digest_memory(hash_alg, data, datalen, + digest, sizeof(digest))) != 0) + goto out; + + ret = openssh_RSA_verify(hash_alg, digest, dlen, 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; +} +#endif /* WITH_OPENSSL */ -- cgit v1.2.3