| /* |
| * 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 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" |
| RCSID("$OpenBSD: authfile.c,v 1.19 2000/09/07 20:27:49 deraadt Exp $"); |
| |
| #include <openssl/bn.h> |
| #include <openssl/dsa.h> |
| #include <openssl/rsa.h> |
| #include <openssl/pem.h> |
| #include <openssl/evp.h> |
| |
| #include "xmalloc.h" |
| #include "buffer.h" |
| #include "bufaux.h" |
| #include "cipher.h" |
| #include "ssh.h" |
| #include "key.h" |
| |
| /* Version identification string for identity files. */ |
| #define AUTHFILE_ID_STRING "SSH PRIVATE KEY FILE FORMAT 1.1\n" |
| |
| /* |
| * Saves the authentication (private) key in a file, encrypting it with |
| * passphrase. The identification of the file (lowest 64 bits of n) will |
| * precede the key to provide identification of the key without needing a |
| * passphrase. |
| */ |
| |
| int |
| save_private_key_rsa(const char *filename, const char *passphrase, |
| RSA *key, const char *comment) |
| { |
| Buffer buffer, encrypted; |
| char buf[100], *cp; |
| int fd, i; |
| CipherContext cipher; |
| int cipher_type; |
| u_int32_t rand; |
| |
| /* |
| * If the passphrase is empty, use SSH_CIPHER_NONE to ease converting |
| * to another cipher; otherwise use SSH_AUTHFILE_CIPHER. |
| */ |
| if (strcmp(passphrase, "") == 0) |
| cipher_type = SSH_CIPHER_NONE; |
| else |
| cipher_type = SSH_AUTHFILE_CIPHER; |
| |
| /* This buffer is used to built the secret part of the private key. */ |
| buffer_init(&buffer); |
| |
| /* Put checkbytes for checking passphrase validity. */ |
| rand = arc4random(); |
| buf[0] = rand & 0xff; |
| buf[1] = (rand >> 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->d); |
| buffer_put_bignum(&buffer, key->iqmp); |
| buffer_put_bignum(&buffer, key->q); /* reverse from SSL p */ |
| buffer_put_bignum(&buffer, key->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. */ |
| cp = AUTHFILE_ID_STRING; |
| for (i = 0; cp[i]; i++) |
| buffer_put_char(&encrypted, cp[i]); |
| buffer_put_char(&encrypted, 0); |
| |
| /* Store cipher type. */ |
| buffer_put_char(&encrypted, cipher_type); |
| 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->n)); |
| buffer_put_bignum(&encrypted, key->n); |
| buffer_put_bignum(&encrypted, key->e); |
| buffer_put_string(&encrypted, comment, strlen(comment)); |
| |
| /* Allocate space for the private part of the key in the buffer. */ |
| buffer_append_space(&encrypted, &cp, buffer_len(&buffer)); |
| |
| cipher_set_key_string(&cipher, cipher_type, passphrase); |
| cipher_encrypt(&cipher, (unsigned char *) cp, |
| (unsigned char *) buffer_ptr(&buffer), |
| buffer_len(&buffer)); |
| memset(&cipher, 0, sizeof(cipher)); |
| |
| /* Destroy temporary data. */ |
| memset(buf, 0, sizeof(buf)); |
| buffer_free(&buffer); |
| |
| fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600); |
| if (fd < 0) |
| return 0; |
| if (write(fd, buffer_ptr(&encrypted), buffer_len(&encrypted)) != |
| buffer_len(&encrypted)) { |
| debug("Write to key file %.200s failed: %.100s", filename, |
| strerror(errno)); |
| buffer_free(&encrypted); |
| close(fd); |
| remove(filename); |
| return 0; |
| } |
| close(fd); |
| buffer_free(&encrypted); |
| return 1; |
| } |
| |
| /* save DSA key in OpenSSL PEM format */ |
| |
| int |
| save_private_key_dsa(const char *filename, const char *passphrase, |
| DSA *dsa, const char *comment) |
| { |
| FILE *fp; |
| int fd; |
| int success = 1; |
| int len = strlen(passphrase); |
| |
| if (len > 0 && len <= 4) { |
| error("passphrase too short: %d bytes", len); |
| errno = 0; |
| return 0; |
| } |
| fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0600); |
| if (fd < 0) { |
| debug("open %s failed", filename); |
| return 0; |
| } |
| fp = fdopen(fd, "w"); |
| if (fp == NULL ) { |
| debug("fdopen %s failed", filename); |
| close(fd); |
| return 0; |
| } |
| if (len > 0) { |
| if (!PEM_write_DSAPrivateKey(fp, dsa, EVP_des_ede3_cbc(), |
| (char *)passphrase, strlen(passphrase), NULL, NULL)) |
| success = 0; |
| } else { |
| if (!PEM_write_DSAPrivateKey(fp, dsa, NULL, |
| NULL, 0, NULL, NULL)) |
| success = 0; |
| } |
| fclose(fp); |
| return success; |
| } |
| |
| int |
| save_private_key(const char *filename, const char *passphrase, Key *key, |
| const char *comment) |
| { |
| switch (key->type) { |
| case KEY_RSA: |
| return save_private_key_rsa(filename, passphrase, key->rsa, comment); |
| break; |
| case KEY_DSA: |
| return save_private_key_dsa(filename, passphrase, key->dsa, comment); |
| break; |
| default: |
| break; |
| } |
| return 0; |
| } |
| |
| /* |
| * Loads the public part of the key file. Returns 0 if an error was |
| * encountered (the file does not exist or is not readable), and non-zero |
| * otherwise. |
| */ |
| |
| int |
| load_public_key_rsa(const char *filename, RSA * pub, char **comment_return) |
| { |
| int fd, i; |
| off_t len; |
| Buffer buffer; |
| char *cp; |
| |
| fd = open(filename, O_RDONLY); |
| if (fd < 0) |
| return 0; |
| len = lseek(fd, (off_t) 0, SEEK_END); |
| lseek(fd, (off_t) 0, SEEK_SET); |
| |
| buffer_init(&buffer); |
| buffer_append_space(&buffer, &cp, len); |
| |
| if (read(fd, cp, (size_t) len) != (size_t) len) { |
| debug("Read from key file %.200s failed: %.100s", filename, |
| strerror(errno)); |
| buffer_free(&buffer); |
| close(fd); |
| return 0; |
| } |
| close(fd); |
| |
| /* Check that it is at least big enought to contain the ID string. */ |
| if (len < strlen(AUTHFILE_ID_STRING) + 1) { |
| debug("Bad key file %.200s.", filename); |
| buffer_free(&buffer); |
| return 0; |
| } |
| /* |
| * Make sure it begins with the id string. Consume the id string |
| * from the buffer. |
| */ |
| for (i = 0; i < (unsigned int) strlen(AUTHFILE_ID_STRING) + 1; i++) |
| if (buffer_get_char(&buffer) != (u_char) AUTHFILE_ID_STRING[i]) { |
| debug("Bad key file %.200s.", filename); |
| buffer_free(&buffer); |
| return 0; |
| } |
| /* Skip cipher type and reserved data. */ |
| (void) buffer_get_char(&buffer); /* cipher type */ |
| (void) buffer_get_int(&buffer); /* reserved */ |
| |
| /* Read the public key from the buffer. */ |
| buffer_get_int(&buffer); |
| /* XXX alloc */ |
| if (pub->n == NULL) |
| pub->n = BN_new(); |
| buffer_get_bignum(&buffer, pub->n); |
| /* XXX alloc */ |
| if (pub->e == NULL) |
| pub->e = BN_new(); |
| buffer_get_bignum(&buffer, pub->e); |
| if (comment_return) |
| *comment_return = buffer_get_string(&buffer, NULL); |
| /* The encrypted private part is not parsed by this function. */ |
| |
| buffer_free(&buffer); |
| |
| return 1; |
| } |
| |
| /* load public key from private-key file */ |
| int |
| load_public_key(const char *filename, Key * key, char **comment_return) |
| { |
| switch (key->type) { |
| case KEY_RSA: |
| return load_public_key_rsa(filename, key->rsa, comment_return); |
| break; |
| case KEY_DSA: |
| default: |
| break; |
| } |
| return 0; |
| } |
| |
| /* |
| * Loads the private key from the file. Returns 0 if an error is encountered |
| * (file does not exist or is not readable, or passphrase is bad). This |
| * initializes the private key. |
| * Assumes we are called under uid of the owner of the file. |
| */ |
| |
| int |
| load_private_key_rsa(int fd, const char *filename, |
| const char *passphrase, RSA * prv, char **comment_return) |
| { |
| int i, check1, check2, cipher_type; |
| off_t len; |
| Buffer buffer, decrypted; |
| char *cp; |
| CipherContext cipher; |
| BN_CTX *ctx; |
| BIGNUM *aux; |
| |
| len = lseek(fd, (off_t) 0, SEEK_END); |
| lseek(fd, (off_t) 0, SEEK_SET); |
| |
| buffer_init(&buffer); |
| buffer_append_space(&buffer, &cp, len); |
| |
| if (read(fd, cp, (size_t) len) != (size_t) len) { |
| debug("Read from key file %.200s failed: %.100s", filename, |
| strerror(errno)); |
| buffer_free(&buffer); |
| close(fd); |
| return 0; |
| } |
| close(fd); |
| |
| /* Check that it is at least big enought to contain the ID string. */ |
| if (len < strlen(AUTHFILE_ID_STRING) + 1) { |
| debug("Bad key file %.200s.", filename); |
| buffer_free(&buffer); |
| return 0; |
| } |
| /* |
| * Make sure it begins with the id string. Consume the id string |
| * from the buffer. |
| */ |
| for (i = 0; i < (unsigned int) strlen(AUTHFILE_ID_STRING) + 1; i++) |
| if (buffer_get_char(&buffer) != (unsigned char) AUTHFILE_ID_STRING[i]) { |
| debug("Bad key file %.200s.", filename); |
| buffer_free(&buffer); |
| return 0; |
| } |
| /* Read cipher type. */ |
| cipher_type = buffer_get_char(&buffer); |
| (void) buffer_get_int(&buffer); /* Reserved data. */ |
| |
| /* Read the public key from the buffer. */ |
| buffer_get_int(&buffer); |
| prv->n = BN_new(); |
| buffer_get_bignum(&buffer, prv->n); |
| prv->e = BN_new(); |
| buffer_get_bignum(&buffer, prv->e); |
| if (comment_return) |
| *comment_return = buffer_get_string(&buffer, NULL); |
| else |
| xfree(buffer_get_string(&buffer, NULL)); |
| |
| /* Check that it is a supported cipher. */ |
| if (((cipher_mask1() | SSH_CIPHER_NONE | SSH_AUTHFILE_CIPHER) & |
| (1 << cipher_type)) == 0) { |
| debug("Unsupported cipher %.100s used in key file %.200s.", |
| cipher_name(cipher_type), filename); |
| buffer_free(&buffer); |
| goto fail; |
| } |
| /* Initialize space for decrypted data. */ |
| buffer_init(&decrypted); |
| buffer_append_space(&decrypted, &cp, buffer_len(&buffer)); |
| |
| /* Rest of the buffer is encrypted. Decrypt it using the passphrase. */ |
| cipher_set_key_string(&cipher, cipher_type, passphrase); |
| cipher_decrypt(&cipher, (unsigned char *) cp, |
| (unsigned char *) buffer_ptr(&buffer), |
| buffer_len(&buffer)); |
| |
| buffer_free(&buffer); |
| |
| 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 key file %.200s.", filename); |
| /* Bad passphrase. */ |
| buffer_free(&decrypted); |
| fail: |
| BN_clear_free(prv->n); |
| prv->n = NULL; |
| BN_clear_free(prv->e); |
| prv->e = NULL; |
| if (comment_return) |
| xfree(*comment_return); |
| return 0; |
| } |
| /* Read the rest of the private key. */ |
| prv->d = BN_new(); |
| buffer_get_bignum(&decrypted, prv->d); |
| prv->iqmp = BN_new(); |
| buffer_get_bignum(&decrypted, prv->iqmp); /* u */ |
| /* in SSL and SSH p and q are exchanged */ |
| prv->q = BN_new(); |
| buffer_get_bignum(&decrypted, prv->q); /* p */ |
| prv->p = BN_new(); |
| buffer_get_bignum(&decrypted, prv->p); /* q */ |
| |
| ctx = BN_CTX_new(); |
| aux = BN_new(); |
| |
| BN_sub(aux, prv->q, BN_value_one()); |
| prv->dmq1 = BN_new(); |
| BN_mod(prv->dmq1, prv->d, aux, ctx); |
| |
| BN_sub(aux, prv->p, BN_value_one()); |
| prv->dmp1 = BN_new(); |
| BN_mod(prv->dmp1, prv->d, aux, ctx); |
| |
| BN_clear_free(aux); |
| BN_CTX_free(ctx); |
| |
| buffer_free(&decrypted); |
| |
| return 1; |
| } |
| |
| int |
| load_private_key_dsa(int fd, const char *passphrase, Key *k, char **comment_return) |
| { |
| DSA *dsa; |
| BIO *in; |
| FILE *fp; |
| |
| in = BIO_new(BIO_s_file()); |
| if (in == NULL) { |
| error("BIO_new failed"); |
| return 0; |
| } |
| fp = fdopen(fd, "r"); |
| if (fp == NULL) { |
| error("fdopen failed"); |
| return 0; |
| } |
| BIO_set_fp(in, fp, BIO_NOCLOSE); |
| dsa = PEM_read_bio_DSAPrivateKey(in, NULL, NULL, (char *)passphrase); |
| if (dsa == NULL) { |
| debug("PEM_read_bio_DSAPrivateKey failed"); |
| } else { |
| /* replace k->dsa with loaded key */ |
| DSA_free(k->dsa); |
| k->dsa = dsa; |
| } |
| BIO_free(in); |
| fclose(fp); |
| if (comment_return) |
| *comment_return = xstrdup("dsa w/o comment"); |
| debug("read DSA private key done"); |
| #ifdef DEBUG_DSS |
| DSA_print_fp(stderr, dsa, 8); |
| #endif |
| return dsa != NULL ? 1 : 0; |
| } |
| |
| int |
| load_private_key(const char *filename, const char *passphrase, Key *key, |
| char **comment_return) |
| { |
| int fd; |
| int ret = 0; |
| struct stat st; |
| |
| fd = open(filename, O_RDONLY); |
| if (fd < 0) |
| return 0; |
| |
| /* check owner and modes */ |
| #ifdef HAVE_CYGWIN |
| if (check_ntsec(filename)) |
| #endif |
| if (fstat(fd, &st) < 0 || |
| (st.st_uid != 0 && st.st_uid != getuid()) || |
| (st.st_mode & 077) != 0) { |
| close(fd); |
| error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
| error("@ WARNING: UNPROTECTED PRIVATE KEY FILE! @"); |
| error("@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@"); |
| error("Bad ownership or mode(0%3.3o) for '%s'.", |
| st.st_mode & 0777, filename); |
| error("It is recommended that your private key files are NOT accessible by others."); |
| return 0; |
| } |
| switch (key->type) { |
| case KEY_RSA: |
| if (key->rsa->e != NULL) { |
| BN_clear_free(key->rsa->e); |
| key->rsa->e = NULL; |
| } |
| if (key->rsa->n != NULL) { |
| BN_clear_free(key->rsa->n); |
| key->rsa->n = NULL; |
| } |
| ret = load_private_key_rsa(fd, filename, passphrase, |
| key->rsa, comment_return); |
| break; |
| case KEY_DSA: |
| ret = load_private_key_dsa(fd, passphrase, key, comment_return); |
| default: |
| break; |
| } |
| close(fd); |
| return ret; |
| } |
| |
| int |
| do_load_public_key(const char *filename, Key *k, char **commentp) |
| { |
| FILE *f; |
| unsigned int bits; |
| char line[1024]; |
| char *cp; |
| |
| f = fopen(filename, "r"); |
| if (f != NULL) { |
| while (fgets(line, sizeof(line), f)) { |
| line[sizeof(line)-1] = '\0'; |
| cp = line; |
| switch(*cp){ |
| case '#': |
| case '\n': |
| case '\0': |
| continue; |
| } |
| /* Skip leading whitespace. */ |
| for (; *cp && (*cp == ' ' || *cp == '\t'); cp++) |
| ; |
| if (*cp) { |
| bits = key_read(k, &cp); |
| if (bits != 0) { |
| if (commentp) |
| *commentp=xstrdup(filename); |
| fclose(f); |
| return 1; |
| } |
| } |
| } |
| fclose(f); |
| } |
| return 0; |
| } |
| |
| /* load public key from pubkey file */ |
| int |
| try_load_public_key(const char *filename, Key *k, char **commentp) |
| { |
| char pub[MAXPATHLEN]; |
| |
| if (do_load_public_key(filename, k, commentp) == 1) |
| return 1; |
| if (strlcpy(pub, filename, sizeof pub) >= MAXPATHLEN) |
| return 0; |
| if (strlcat(pub, ".pub", sizeof pub) >= MAXPATHLEN) |
| return 0; |
| if (do_load_public_key(pub, k, commentp) == 1) |
| return 1; |
| return 0; |
| } |