/* $OpenBSD: authfile.c,v 1.105 2014/04/28 03:09:18 djm Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland * All rights reserved * This file contains functions for reading and writing identity files, and * for reading the passphrase from the user. * * As far as I am concerned, the code I have written for this software * can be used freely for any purpose. Any derived versions of this * software must be clearly marked as such, and if the derived work is * incompatible with the protocol description in the RFC file, it must be * called by a name other than "ssh" or "Secure Shell". * * * Copyright (c) 2000, 2013 Markus Friedl. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ #include #include #include #include #include #include #include #include "crypto_api.h" #include #include #include #include #include #include #include #include "xmalloc.h" #include "cipher.h" #include "buffer.h" #include "key.h" #include "ssh.h" #include "log.h" #include "authfile.h" #include "rsa.h" #include "misc.h" #include "atomicio.h" #include "uuencode.h" /* openssh private key file format */ #define MARK_BEGIN "-----BEGIN OPENSSH PRIVATE KEY-----\n" #define MARK_END "-----END OPENSSH PRIVATE KEY-----\n" #define KDFNAME "bcrypt" #define AUTH_MAGIC "openssh-key-v1" #define SALT_LEN 16 #define DEFAULT_CIPHERNAME "aes256-cbc" #define DEFAULT_ROUNDS 16 #define MAX_KEY_FILE_SIZE (1024 * 1024) /* Version identification string for SSH v1 identity files. */ static const char authfile_id_string[] = "SSH PRIVATE KEY FILE FORMAT 1.1\n"; static int key_private_to_blob2(Key *prv, Buffer *blob, const char *passphrase, const char *comment, const char *ciphername, int rounds) { u_char *key, *cp, salt[SALT_LEN]; size_t keylen, ivlen, blocksize, authlen; u_int len, check; int i, n; const Cipher *c; Buffer encoded, b, kdf; CipherContext ctx; const char *kdfname = KDFNAME; if (rounds <= 0) rounds = DEFAULT_ROUNDS; if (passphrase == NULL || !strlen(passphrase)) { ciphername = "none"; kdfname = "none"; } else if (ciphername == NULL) ciphername = DEFAULT_CIPHERNAME; else if (cipher_number(ciphername) != SSH_CIPHER_SSH2) fatal("invalid cipher"); if ((c = cipher_by_name(ciphername)) == NULL) fatal("unknown cipher name"); buffer_init(&kdf); blocksize = cipher_blocksize(c); keylen = cipher_keylen(c); ivlen = cipher_ivlen(c); authlen = cipher_authlen(c); key = xcalloc(1, keylen + ivlen); if (strcmp(kdfname, "none") != 0) { arc4random_buf(salt, SALT_LEN); if (bcrypt_pbkdf(passphrase, strlen(passphrase), salt, SALT_LEN, key, keylen + ivlen, rounds) < 0) fatal("bcrypt_pbkdf failed"); buffer_put_string(&kdf, salt, SALT_LEN); buffer_put_int(&kdf, rounds); } cipher_init(&ctx, c, key, keylen, key + keylen , ivlen, 1); explicit_bzero(key, keylen + ivlen); free(key); buffer_init(&encoded); buffer_append(&encoded, AUTH_MAGIC, sizeof(AUTH_MAGIC)); buffer_put_cstring(&encoded, ciphername); buffer_put_cstring(&encoded, kdfname); buffer_put_string(&encoded, buffer_ptr(&kdf), buffer_len(&kdf)); buffer_put_int(&encoded, 1); /* number of keys */ key_to_blob(prv, &cp, &len); /* public key */ buffer_put_string(&encoded, cp, len); explicit_bzero(cp, len); free(cp); buffer_free(&kdf); /* set up the buffer that will be encrypted */ buffer_init(&b); /* Random check bytes */ check = arc4random(); buffer_put_int(&b, check); buffer_put_int(&b, check); /* append private key and comment*/ key_private_serialize(prv, &b); buffer_put_cstring(&b, comment); /* padding */ i = 0; while (buffer_len(&b) % blocksize) buffer_put_char(&b, ++i & 0xff); /* length */ buffer_put_int(&encoded, buffer_len(&b)); /* encrypt */ cp = buffer_append_space(&encoded, buffer_len(&b) + authlen); if (cipher_crypt(&ctx, 0, cp, buffer_ptr(&b), buffer_len(&b), 0, authlen) != 0) fatal("%s: cipher_crypt failed", __func__); buffer_free(&b); cipher_cleanup(&ctx); /* uuencode */ len = 2 * buffer_len(&encoded); cp = xmalloc(len); n = uuencode(buffer_ptr(&encoded), buffer_len(&encoded), (char *)cp, len); if (n < 0) fatal("%s: uuencode", __func__); buffer_clear(blob); buffer_append(blob, MARK_BEGIN, sizeof(MARK_BEGIN) - 1); for (i = 0; i < n; i++) { buffer_put_char(blob, cp[i]); if (i % 70 == 69) buffer_put_char(blob, '\n'); } if (i % 70 != 69) buffer_put_char(blob, '\n'); buffer_append(blob, MARK_END, sizeof(MARK_END) - 1); free(cp); return buffer_len(blob); } static Key * key_parse_private2(Buffer *blob, int type, const char *passphrase, char **commentp) { u_char *key = NULL, *cp, *salt = NULL, pad, last; char *comment = NULL, *ciphername = NULL, *kdfname = NULL; const u_char *kdfp; u_int keylen = 0, ivlen, blocksize, slen, klen, len, rounds, nkeys; u_int check1, check2, m1len, m2len; size_t authlen; const Cipher *c; Buffer b, encoded, copy, kdf; CipherContext ctx; Key *k = NULL; int dlen, ret, i; buffer_init(&b); buffer_init(&kdf); buffer_init(&encoded); buffer_init(©); /* uudecode */ m1len = sizeof(MARK_BEGIN) - 1; m2len = sizeof(MARK_END) - 1; cp = buffer_ptr(blob); len = buffer_len(blob); if (len < m1len || memcmp(cp, MARK_BEGIN, m1len)) { debug("%s: missing begin marker", __func__); goto out; } cp += m1len; len -= m1len; while (len) { if (*cp != '\n' && *cp != '\r') buffer_put_char(&encoded, *cp); last = *cp; len--; cp++; if (last == '\n') { if (len >= m2len && !memcmp(cp, MARK_END, m2len)) { buffer_put_char(&encoded, '\0'); break; } } } if (!len) { debug("%s: no end marker", __func__); goto out; } len = buffer_len(&encoded); if ((cp = buffer_append_space(©, len)) == NULL) { error("%s: buffer_append_space", __func__); goto out; } if ((dlen = uudecode(buffer_ptr(&encoded), cp, len)) < 0) { error("%s: uudecode failed", __func__); goto out; } if ((u_int)dlen > len) { error("%s: crazy uudecode length %d > %u", __func__, dlen, len); goto out; } buffer_consume_end(©, len - dlen); if (buffer_len(©) < sizeof(AUTH_MAGIC) || memcmp(buffer_ptr(©), AUTH_MAGIC, sizeof(AUTH_MAGIC))) { error("%s: bad magic", __func__); goto out; } buffer_consume(©, sizeof(AUTH_MAGIC)); ciphername = buffer_get_cstring_ret(©, NULL); if (ciphername == NULL || (c = cipher_by_name(ciphername)) == NULL) { error("%s: unknown cipher name", __func__); goto out; } if ((passphrase == NULL || !strlen(passphrase)) && strcmp(ciphername, "none") != 0) { /* passphrase required */ goto out; } kdfname = buffer_get_cstring_ret(©, NULL); if (kdfname == NULL || (strcmp(kdfname, "none") != 0 && strcmp(kdfname, "bcrypt") != 0)) { error("%s: unknown kdf name", __func__); goto out; } if (!strcmp(kdfname, "none") && strcmp(ciphername, "none") != 0) { error("%s: cipher %s requires kdf", __func__, ciphername); goto out; } /* kdf options */ kdfp = buffer_get_string_ptr_ret(©, &klen); if (kdfp == NULL) { error("%s: kdf options not set", __func__); goto out; } if (klen > 0) { if ((cp = buffer_append_space(&kdf, klen)) == NULL) { error("%s: kdf alloc failed", __func__); goto out; } memcpy(cp, kdfp, klen); } /* number of keys */ if (buffer_get_int_ret(&nkeys, ©) < 0) { error("%s: key counter missing", __func__); goto out; } if (nkeys != 1) { error("%s: only one key supported", __func__); goto out; } /* pubkey */ if ((cp = buffer_get_string_ret(©, &len)) == NULL) { error("%s: pubkey not found", __func__); goto out; } free(cp); /* XXX check pubkey against decrypted private key */ /* size of encrypted key blob */ len = buffer_get_int(©); blocksize = cipher_blocksize(c); authlen = cipher_authlen(c); if (len < blocksize) { error("%s: encrypted data too small", __func__); goto out; } if (len % blocksize) { error("%s: length not multiple of blocksize", __func__); goto out; } /* setup key */ keylen = cipher_keylen(c); ivlen = cipher_ivlen(c); key = xcalloc(1, keylen + ivlen); if (!strcmp(kdfname, "bcrypt")) { if ((salt = buffer_get_string_ret(&kdf, &slen)) == NULL) { error("%s: salt not set", __func__); goto out; } if (buffer_get_int_ret(&rounds, &kdf) < 0) { error("%s: rounds not set", __func__); goto out; } if (bcrypt_pbkdf(passphrase, strlen(passphrase), salt, slen, key, keylen + ivlen, rounds) < 0) { error("%s: bcrypt_pbkdf failed", __func__); goto out; } } cp = buffer_append_space(&b, len); cipher_init(&ctx, c, key, keylen, key + keylen, ivlen, 0); ret = cipher_crypt(&ctx, 0, cp, buffer_ptr(©), len, 0, authlen); cipher_cleanup(&ctx); buffer_consume(©, len); /* fail silently on decryption errors */ if (ret != 0) { debug("%s: decrypt failed", __func__); goto out; } if (buffer_len(©) != 0) { error("%s: key blob has trailing data (len = %u)", __func__, buffer_len(©)); goto out; } /* check bytes */ if (buffer_get_int_ret(&check1, &b) < 0 || buffer_get_int_ret(&check2, &b) < 0) { error("check bytes missing"); goto out; } if (check1 != check2) { debug("%s: decrypt failed: 0x%08x != 0x%08x", __func__, check1, check2); goto out; } k = key_private_deserialize(&b); /* comment */ comment = buffer_get_cstring_ret(&b, NULL); i = 0; while (buffer_len(&b)) { if (buffer_get_char_ret(&pad, &b) == -1 || pad != (++i & 0xff)) { error("%s: bad padding", __func__); key_free(k); k = NULL; goto out; } } if (k && commentp) { *commentp = comment; comment = NULL; } /* XXX decode pubkey and check against private */ out: free(ciphername); free(kdfname); free(salt); free(comment); if (key) explicit_bzero(key, keylen + ivlen); free(key); buffer_free(&encoded); buffer_free(©); buffer_free(&kdf); buffer_free(&b); return k; } /* * Serialises the authentication (private) key to a blob, encrypting it with * passphrase. The identification of the blob (lowest 64 bits of n) will * precede the key to provide identification of the key without needing a * passphrase. */ static int key_private_rsa1_to_blob(Key *key, Buffer *blob, const char *passphrase, const char *comment) { Buffer buffer, encrypted; u_char buf[100], *cp; int i, cipher_num; CipherContext ciphercontext; const Cipher *cipher; u_int32_t rnd; /* * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting * to another cipher; otherwise use SSH_AUTHFILE_CIPHER. */ cipher_num = (strcmp(passphrase, "") == 0) ? SSH_CIPHER_NONE : SSH_AUTHFILE_CIPHER; if ((cipher = cipher_by_number(cipher_num)) == NULL) fatal("save_private_key_rsa: bad cipher"); /* This buffer is used to built the secret part of the private key. */ buffer_init(&buffer); /* Put checkbytes for checking passphrase validity. */ rnd = arc4random(); buf[0] = rnd & 0xff; buf[1] = (rnd >> 8) & 0xff; buf[2] = buf[0]; buf[3] = buf[1]; buffer_append(&buffer, buf, 4); /* * Store the private key (n and e will not be stored because they * will be stored in plain text, and storing them also in encrypted * format would just give known plaintext). */ buffer_put_bignum(&buffer, key->rsa->d); buffer_put_bignum(&buffer, key->rsa->iqmp); buffer_put_bignum(&buffer, key->rsa->q); /* reverse from SSL p */ buffer_put_bignum(&buffer, key->rsa->p); /* reverse from SSL q */ /* Pad the part to be encrypted until its size is a multiple of 8. */ while (buffer_len(&buffer) % 8 != 0) buffer_put_char(&buffer, 0); /* This buffer will be used to contain the data in the file. */ buffer_init(&encrypted); /* First store keyfile id string. */ for (i = 0; authfile_id_string[i]; i++) buffer_put_char(&encrypted, authfile_id_string[i]); buffer_put_char(&encrypted, 0); /* Store cipher type. */ buffer_put_char(&encrypted, cipher_num); buffer_put_int(&encrypted, 0); /* For future extension */ /* Store public key. This will be in plain text. */ buffer_put_int(&encrypted, BN_num_bits(key->rsa->n)); buffer_put_bignum(&encrypted, key->rsa->n); buffer_put_bignum(&encrypted, key->rsa->e); buffer_put_cstring(&encrypted, comment); /* Allocate space for the private part of the key in the buffer. */ cp = buffer_append_space(&encrypted, buffer_len(&buffer)); cipher_set_key_string(&ciphercontext, cipher, passphrase, CIPHER_ENCRYPT); if (cipher_crypt(&ciphercontext, 0, cp, buffer_ptr(&buffer), buffer_len(&buffer), 0, 0) != 0) fatal("%s: cipher_crypt failed", __func__); cipher_cleanup(&ciphercontext); explicit_bzero(&ciphercontext, sizeof(ciphercontext)); /* Destroy temporary data. */ explicit_bzero(buf, sizeof(buf)); buffer_free(&buffer); buffer_append(blob, buffer_ptr(&encrypted), buffer_len(&encrypted)); buffer_free(&encrypted); return 1; } /* convert SSH v2 key in OpenSSL PEM format */ static int key_private_pem_to_blob(Key *key, Buffer *blob, const char *_passphrase, const char *comment) { int success = 0; int blen, len = strlen(_passphrase); u_char *passphrase = (len > 0) ? (u_char *)_passphrase : NULL; const EVP_CIPHER *cipher = (len > 0) ? EVP_aes_128_cbc() : NULL; const u_char *bptr; BIO *bio; if (len > 0 && len <= 4) { error("passphrase too short: have %d bytes, need > 4", len); return 0; } if ((bio = BIO_new(BIO_s_mem())) == NULL) { error("%s: BIO_new failed", __func__); return 0; } switch (key->type) { case KEY_DSA: success = PEM_write_bio_DSAPrivateKey(bio, key->dsa, cipher, passphrase, len, NULL, NULL); break; case KEY_ECDSA: success = PEM_write_bio_ECPrivateKey(bio, key->ecdsa, cipher, passphrase, len, NULL, NULL); break; case KEY_RSA: success = PEM_write_bio_RSAPrivateKey(bio, key->rsa, cipher, passphrase, len, NULL, NULL); break; } if (success) { if ((blen = BIO_get_mem_data(bio, &bptr)) <= 0) success = 0; else buffer_append(blob, bptr, blen); } BIO_free(bio); return success; } /* Save a key blob to a file */ static int key_save_private_blob(Buffer *keybuf, const char *filename) { int fd; if ((fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600)) < 0) { error("open %s failed: %s.", filename, strerror(errno)); return 0; } if (atomicio(vwrite, fd, buffer_ptr(keybuf), buffer_len(keybuf)) != buffer_len(keybuf)) { error("write to key file %s failed: %s", filename, strerror(errno)); close(fd); unlink(filename); return 0; } close(fd); return 1; } /* Serialise "key" to buffer "blob" */ static int key_private_to_blob(Key *key, Buffer *blob, const char *passphrase, const char *comment, int force_new_format, const char *new_format_cipher, int new_format_rounds) { switch (key->type) { case KEY_RSA1: return key_private_rsa1_to_blob(key, blob, passphrase, comment); case KEY_DSA: case KEY_ECDSA: case KEY_RSA: if (force_new_format) { return key_private_to_blob2(key, blob, passphrase, comment, new_format_cipher, new_format_rounds); } return key_private_pem_to_blob(key, blob, passphrase, comment); case KEY_ED25519: return key_private_to_blob2(key, blob, passphrase, comment, new_format_cipher, new_format_rounds); default: error("%s: cannot save key type %d", __func__, key->type); return 0; } } int key_save_private(Key *key, const char *filename, const char *passphrase, const char *comment, int force_new_format, const char *new_format_cipher, int new_format_rounds) { Buffer keyblob; int success = 0; buffer_init(&keyblob); if (!key_private_to_blob(key, &keyblob, passphrase, comment, force_new_format, new_format_cipher, new_format_rounds)) goto out; if (!key_save_private_blob(&keyblob, filename)) goto out; success = 1; out: buffer_free(&keyblob); return success; } /* * Parse the public, unencrypted portion of a RSA1 key. */ static Key * key_parse_public_rsa1(Buffer *blob, char **commentp) { Key *pub; Buffer copy; /* Check that it is at least big enough to contain the ID string. */ if (buffer_len(blob) < sizeof(authfile_id_string)) { debug3("Truncated RSA1 identifier"); return NULL; } /* * Make sure it begins with the id string. Consume the id string * from the buffer. */ if (memcmp(buffer_ptr(blob), authfile_id_string, sizeof(authfile_id_string)) != 0) { debug3("Incorrect RSA1 identifier"); return NULL; } buffer_init(©); buffer_append(©, buffer_ptr(blob), buffer_len(blob)); buffer_consume(©, sizeof(authfile_id_string)); /* Skip cipher type and reserved data. */ (void) buffer_get_char(©); /* cipher type */ (void) buffer_get_int(©); /* reserved */ /* Read the public key from the buffer. */ (void) buffer_get_int(©); pub = key_new(KEY_RSA1); buffer_get_bignum(©, pub->rsa->n); buffer_get_bignum(©, pub->rsa->e); if (commentp) *commentp = buffer_get_string(©, NULL); /* The encrypted private part is not parsed by this function. */ buffer_free(©); return pub; } /* Load a key from a fd into a buffer */ int key_load_file(int fd, const char *filename, Buffer *blob) { u_char buf[1024]; size_t len; struct stat st; if (fstat(fd, &st) < 0) { error("%s: fstat of key file %.200s%sfailed: %.100s", __func__, filename == NULL ? "" : filename, filename == NULL ? "" : " ", strerror(errno)); return 0; } if ((st.st_mode & (S_IFSOCK|S_IFCHR|S_IFIFO)) == 0 && st.st_size > MAX_KEY_FILE_SIZE) { toobig: error("%s: key file %.200s%stoo large", __func__, filename == NULL ? "" : filename, filename == NULL ? "" : " "); return 0; } buffer_clear(blob); for (;;) { if ((len = atomicio(read, fd, buf, sizeof(buf))) == 0) { if (errno == EPIPE) break; debug("%s: read from key file %.200s%sfailed: %.100s", __func__, filename == NULL ? "" : filename, filename == NULL ? "" : " ", strerror(errno)); buffer_clear(blob); explicit_bzero(buf, sizeof(buf)); return 0; } buffer_append(blob, buf, len); if (buffer_len(blob) > MAX_KEY_FILE_SIZE) { buffer_clear(blob); explicit_bzero(buf, sizeof(buf)); goto toobig; } } explicit_bzero(buf, sizeof(buf)); if ((st.st_mode & (S_IFSOCK|S_IFCHR|S_IFIFO)) == 0 && st.st_size != buffer_len(blob)) { debug("%s: key file %.200s%schanged size while reading", __func__, filename == NULL ? "" : filename, filename == NULL ? "" : " "); buffer_clear(blob); return 0; } return 1; } /* * Loads the public part of the ssh v1 key file. Returns NULL if an error was * encountered (the file does not exist or is not readable), and the key * otherwise. */ static Key * key_load_public_rsa1(int fd, const char *filename, char **commentp) { Buffer buffer; Key *pub; buffer_init(&buffer); if (!key_load_file(fd, filename, &buffer)) { buffer_free(&buffer); return NULL; } pub = key_parse_public_rsa1(&buffer, commentp); if (pub == NULL) debug3("Could not load \"%s\" as a RSA1 public key", filename); buffer_free(&buffer); return pub; } /* load public key from private-key file, works only for SSH v1 */ Key * key_load_public_type(int type, const char *filename, char **commentp) { Key *pub; int fd; if (type == KEY_RSA1) { fd = open(filename, O_RDONLY); if (fd < 0) return NULL; pub = key_load_public_rsa1(fd, filename, commentp); close(fd); return pub; } return NULL; } static Key * key_parse_private_rsa1(Buffer *blob, const char *passphrase, char **commentp) { int check1, check2, cipher_type; Buffer decrypted; u_char *cp; CipherContext ciphercontext; const Cipher *cipher; Key *prv = NULL; Buffer copy; /* Check that it is at least big enough to contain the ID string. */ if (buffer_len(blob) < sizeof(authfile_id_string)) { debug3("Truncated RSA1 identifier"); return NULL; } /* * Make sure it begins with the id string. Consume the id string * from the buffer. */ if (memcmp(buffer_ptr(blob), authfile_id_string, sizeof(authfile_id_string)) != 0) { debug3("Incorrect RSA1 identifier"); return NULL; } buffer_init(©); buffer_append(©, buffer_ptr(blob), buffer_len(blob)); buffer_consume(©, sizeof(authfile_id_string)); /* Read cipher type. */ cipher_type = buffer_get_char(©); (void) buffer_get_int(©); /* Reserved data. */ /* Read the public key from the buffer. */ (void) buffer_get_int(©); prv = key_new_private(KEY_RSA1); buffer_get_bignum(©, prv->rsa->n); buffer_get_bignum(©, prv->rsa->e); if (commentp) *commentp = buffer_get_string(©, NULL); else (void)buffer_get_string_ptr(©, NULL); /* Check that it is a supported cipher. */ cipher = cipher_by_number(cipher_type); if (cipher == NULL) { debug("Unsupported RSA1 cipher %d", cipher_type); buffer_free(©); goto fail; } /* Initialize space for decrypted data. */ buffer_init(&decrypted); cp = buffer_append_space(&decrypted, buffer_len(©)); /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */ cipher_set_key_string(&ciphercontext, cipher, passphrase, CIPHER_DECRYPT); if (cipher_crypt(&ciphercontext, 0, cp, buffer_ptr(©), buffer_len(©), 0, 0) != 0) fatal("%s: cipher_crypt failed", __func__); cipher_cleanup(&ciphercontext); explicit_bzero(&ciphercontext, sizeof(ciphercontext)); buffer_free(©); check1 = buffer_get_char(&decrypted); check2 = buffer_get_char(&decrypted); if (check1 != buffer_get_char(&decrypted) || check2 != buffer_get_char(&decrypted)) { if (strcmp(passphrase, "") != 0) debug("Bad passphrase supplied for RSA1 key"); /* Bad passphrase. */ buffer_free(&decrypted); goto fail; } /* Read the rest of the private key. */ buffer_get_bignum(&decrypted, prv->rsa->d); buffer_get_bignum(&decrypted, prv->rsa->iqmp); /* u */ /* in SSL and SSH v1 p and q are exchanged */ buffer_get_bignum(&decrypted, prv->rsa->q); /* p */ buffer_get_bignum(&decrypted, prv->rsa->p); /* q */ /* calculate p-1 and q-1 */ rsa_generate_additional_parameters(prv->rsa); buffer_free(&decrypted); /* enable blinding */ if (RSA_blinding_on(prv->rsa, NULL) != 1) { error("%s: RSA_blinding_on failed", __func__); goto fail; } return prv; fail: if (commentp != NULL) free(*commentp); key_free(prv); return NULL; } static Key * key_parse_private_pem(Buffer *blob, int type, const char *passphrase, char **commentp) { EVP_PKEY *pk = NULL; Key *prv = NULL; char *name = ""; BIO *bio; if ((bio = BIO_new_mem_buf(buffer_ptr(blob), buffer_len(blob))) == NULL) { error("%s: BIO_new_mem_buf failed", __func__); return NULL; } pk = PEM_read_bio_PrivateKey(bio, NULL, NULL, (char *)passphrase); BIO_free(bio); if (pk == NULL) { debug("%s: PEM_read_PrivateKey failed", __func__); (void)ERR_get_error(); } else if (pk->type == EVP_PKEY_RSA && (type == KEY_UNSPEC||type==KEY_RSA)) { prv = key_new(KEY_UNSPEC); prv->rsa = EVP_PKEY_get1_RSA(pk); prv->type = KEY_RSA; name = "rsa w/o comment"; #ifdef DEBUG_PK RSA_print_fp(stderr, prv->rsa, 8); #endif if (RSA_blinding_on(prv->rsa, NULL) != 1) { error("%s: RSA_blinding_on failed", __func__); key_free(prv); prv = NULL; } } else if (pk->type == EVP_PKEY_DSA && (type == KEY_UNSPEC||type==KEY_DSA)) { prv = key_new(KEY_UNSPEC); prv->dsa = EVP_PKEY_get1_DSA(pk); prv->type = KEY_DSA; name = "dsa w/o comment"; #ifdef DEBUG_PK DSA_print_fp(stderr, prv->dsa, 8); #endif } else if (pk->type == EVP_PKEY_EC && (type == KEY_UNSPEC||type==KEY_ECDSA)) { prv = key_new(KEY_UNSPEC); prv->ecdsa = EVP_PKEY_get1_EC_KEY(pk); prv->type = KEY_ECDSA; if ((prv->ecdsa_nid = key_ecdsa_key_to_nid(prv->ecdsa)) == -1 || key_curve_nid_to_name(prv->ecdsa_nid) == NULL || key_ec_validate_public(EC_KEY_get0_group(prv->ecdsa), EC_KEY_get0_public_key(prv->ecdsa)) != 0 || key_ec_validate_private(prv->ecdsa) != 0) { error("%s: bad ECDSA key", __func__); key_free(prv); prv = NULL; } name = "ecdsa w/o comment"; #ifdef DEBUG_PK if (prv != NULL && prv->ecdsa != NULL) key_dump_ec_key(prv->ecdsa); #endif } else { error("%s: PEM_read_PrivateKey: mismatch or " "unknown EVP_PKEY save_type %d", __func__, pk->save_type); } if (pk != NULL) EVP_PKEY_free(pk); if (prv != NULL && commentp) *commentp = xstrdup(name); debug("read PEM private key done: type %s", prv ? key_type(prv) : ""); return prv; } Key * key_load_private_pem(int fd, int type, const char *passphrase, char **commentp) { Buffer buffer; Key *prv; buffer_init(&buffer); if (!key_load_file(fd, NULL, &buffer)) { buffer_free(&buffer); return NULL; } prv = key_parse_private_pem(&buffer, type, passphrase, commentp); buffer_free(&buffer); return prv; } int key_perm_ok(int fd, const char *filename) { struct stat st; if (fstat(fd, &st) < 0) return 0; /* * if a key owned by the user is accessed, then we check the * permissions of the file. if the key owned by a different user, * then we don't care. */ if ((st.st_uid == getuid()) && (st.st_mode & 077) != 0) { error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @"); error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); error("Permissions 0%3.3o for '%s' are too open.", (u_int)st.st_mode & 0777, filename); error("It is recommended that your private key files are NOT accessible by others."); error("This private key will be ignored."); return 0; } return 1; } static Key * key_parse_private_type(Buffer *blob, int type, const char *passphrase, char **commentp) { Key *k; switch (type) { case KEY_RSA1: return key_parse_private_rsa1(blob, passphrase, commentp); case KEY_DSA: case KEY_ECDSA: case KEY_RSA: return key_parse_private_pem(blob, type, passphrase, commentp); case KEY_ED25519: return key_parse_private2(blob, type, passphrase, commentp); case KEY_UNSPEC: if ((k = key_parse_private2(blob, type, passphrase, commentp))) return k; return key_parse_private_pem(blob, type, passphrase, commentp); default: error("%s: cannot parse key type %d", __func__, type); break; } return NULL; } Key * key_load_private_type(int type, const char *filename, const char *passphrase, char **commentp, int *perm_ok) { int fd; Key *ret; Buffer buffer; fd = open(filename, O_RDONLY); if (fd < 0) { debug("could not open key file '%s': %s", filename, strerror(errno)); if (perm_ok != NULL) *perm_ok = 0; return NULL; } if (!key_perm_ok(fd, filename)) { if (perm_ok != NULL) *perm_ok = 0; error("bad permissions: ignore key: %s", filename); close(fd); return NULL; } if (perm_ok != NULL) *perm_ok = 1; buffer_init(&buffer); if (!key_load_file(fd, filename, &buffer)) { buffer_free(&buffer); close(fd); return NULL; } close(fd); ret = key_parse_private_type(&buffer, type, passphrase, commentp); buffer_free(&buffer); return ret; } Key * key_parse_private(Buffer *buffer, const char *filename, const char *passphrase, char **commentp) { Key *pub, *prv; /* it's a SSH v1 key if the public key part is readable */ pub = key_parse_public_rsa1(buffer, commentp); if (pub == NULL) { prv = key_parse_private_type(buffer, KEY_UNSPEC, passphrase, NULL); /* use the filename as a comment for PEM */ if (commentp && prv) *commentp = xstrdup(filename); } else { key_free(pub); /* key_parse_public_rsa1() has already loaded the comment */ prv = key_parse_private_type(buffer, KEY_RSA1, passphrase, NULL); } return prv; } Key * key_load_private(const char *filename, const char *passphrase, char **commentp) { Key *prv; Buffer buffer; int fd; fd = open(filename, O_RDONLY); if (fd < 0) { debug("could not open key file '%s': %s", filename, strerror(errno)); return NULL; } if (!key_perm_ok(fd, filename)) { error("bad permissions: ignore key: %s", filename); close(fd); return NULL; } buffer_init(&buffer); if (!key_load_file(fd, filename, &buffer)) { buffer_free(&buffer); close(fd); return NULL; } close(fd); prv = key_parse_private(&buffer, filename, passphrase, commentp); buffer_free(&buffer); return prv; } static int key_try_load_public(Key *k, const char *filename, char **commentp) { FILE *f; char line[SSH_MAX_PUBKEY_BYTES]; char *cp; u_long linenum = 0; f = fopen(filename, "r"); if (f != NULL) { while (read_keyfile_line(f, filename, line, sizeof(line), &linenum) != -1) { cp = line; switch (*cp) { case '#': case '\n': case '\0': continue; } /* Abort loading if this looks like a private key */ if (strncmp(cp, "-----BEGIN", 10) == 0) break; /* Skip leading whitespace. */ for (; *cp && (*cp == ' ' || *cp == '\t'); cp++) ; if (*cp) { if (key_read(k, &cp) == 1) { cp[strcspn(cp, "\r\n")] = '\0'; if (commentp) { *commentp = xstrdup(*cp ? cp : filename); } fclose(f); return 1; } } } fclose(f); } return 0; } /* load public key from ssh v1 private or any pubkey file */ Key * key_load_public(const char *filename, char **commentp) { Key *pub; char file[MAXPATHLEN]; /* try rsa1 private key */ pub = key_load_public_type(KEY_RSA1, filename, commentp); if (pub != NULL) return pub; /* try rsa1 public key */ pub = key_new(KEY_RSA1); if (key_try_load_public(pub, filename, commentp) == 1) return pub; key_free(pub); /* try ssh2 public key */ pub = key_new(KEY_UNSPEC); if (key_try_load_public(pub, filename, commentp) == 1) return pub; if ((strlcpy(file, filename, sizeof file) < sizeof(file)) && (strlcat(file, ".pub", sizeof file) < sizeof(file)) && (key_try_load_public(pub, file, commentp) == 1)) return pub; key_free(pub); return NULL; } /* Load the certificate associated with the named private key */ Key * key_load_cert(const char *filename) { Key *pub; char *file; pub = key_new(KEY_UNSPEC); xasprintf(&file, "%s-cert.pub", filename); if (key_try_load_public(pub, file, NULL) == 1) { free(file); return pub; } free(file); key_free(pub); return NULL; } /* Load private key and certificate */ Key * key_load_private_cert(int type, const char *filename, const char *passphrase, int *perm_ok) { Key *key, *pub; switch (type) { case KEY_RSA: case KEY_DSA: case KEY_ECDSA: case KEY_ED25519: break; default: error("%s: unsupported key type", __func__); return NULL; } if ((key = key_load_private_type(type, filename, passphrase, NULL, perm_ok)) == NULL) return NULL; if ((pub = key_load_cert(filename)) == NULL) { key_free(key); return NULL; } /* Make sure the private key matches the certificate */ if (key_equal_public(key, pub) == 0) { error("%s: certificate does not match private key %s", __func__, filename); } else if (key_to_certified(key, key_cert_is_legacy(pub)) != 0) { error("%s: key_to_certified failed", __func__); } else { key_cert_copy(pub, key); key_free(pub); return key; } key_free(key); key_free(pub); return NULL; } /* * Returns 1 if the specified "key" is listed in the file "filename", * 0 if the key is not listed or -1 on error. * If strict_type is set then the key type must match exactly, * otherwise a comparison that ignores certficiate data is performed. */ int key_in_file(Key *key, const char *filename, int strict_type) { FILE *f; char line[SSH_MAX_PUBKEY_BYTES]; char *cp; u_long linenum = 0; int ret = 0; Key *pub; int (*key_compare)(const Key *, const Key *) = strict_type ? key_equal : key_equal_public; if ((f = fopen(filename, "r")) == NULL) { if (errno == ENOENT) { debug("%s: keyfile \"%s\" missing", __func__, filename); return 0; } else { error("%s: could not open keyfile \"%s\": %s", __func__, filename, strerror(errno)); return -1; } } while (read_keyfile_line(f, filename, line, sizeof(line), &linenum) != -1) { cp = line; /* Skip leading whitespace. */ for (; *cp && (*cp == ' ' || *cp == '\t'); cp++) ; /* Skip comments and empty lines */ switch (*cp) { case '#': case '\n': case '\0': continue; } pub = key_new(KEY_UNSPEC); if (key_read(pub, &cp) != 1) { key_free(pub); continue; } if (key_compare(key, pub)) { ret = 1; key_free(pub); break; } key_free(pub); } fclose(f); return ret; }