diff options
Diffstat (limited to 'crypto/openssh/authfile.c')
| -rw-r--r-- | crypto/openssh/authfile.c | 1308 |
1 files changed, 1308 insertions, 0 deletions
diff --git a/crypto/openssh/authfile.c b/crypto/openssh/authfile.c new file mode 100644 index 000000000000..d7eaa9dec49c --- /dev/null +++ b/crypto/openssh/authfile.c @@ -0,0 +1,1308 @@ +/* $OpenBSD: authfile.c,v 1.103 2014/02/02 03:44:31 djm Exp $ */ +/* + * Author: Tatu Ylonen <ylo@cs.hut.fi> + * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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 "includes.h" + +#include <sys/types.h> +#include <sys/stat.h> +#include <sys/param.h> +#include <sys/uio.h> + +#include <openssl/err.h> +#include <openssl/evp.h> +#include <openssl/pem.h> + +/* compatibility with old or broken OpenSSL versions */ +#include "openbsd-compat/openssl-compat.h" + +#include "crypto_api.h" + +#include <errno.h> +#include <fcntl.h> +#include <stdarg.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <unistd.h> + +#ifdef HAVE_UTIL_H +#include <util.h> +#endif + +#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, *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") && !strcmp(kdfname, "bcrypt"))) { + 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; +#if (OPENSSL_VERSION_NUMBER < 0x00907000L) + const EVP_CIPHER *cipher = (len > 0) ? EVP_des_ede3_cbc() : NULL; +#else + const EVP_CIPHER *cipher = (len > 0) ? EVP_aes_128_cbc() : NULL; +#endif + 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; +#ifdef OPENSSL_HAS_ECC + case KEY_ECDSA: + success = PEM_write_bio_ECPrivateKey(bio, key->ecdsa, + cipher, passphrase, len, NULL, NULL); + break; +#endif + 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 = "<no key>"; + 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 +#ifdef OPENSSL_HAS_ECC + } 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 +#endif /* OPENSSL_HAS_ECC */ + } 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) : "<unknown>"); + 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. + */ +#ifdef HAVE_CYGWIN + if (check_ntsec(filename)) +#endif + 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 required 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; +} |