Initial revision
diff --git a/authfile.c b/authfile.c
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+/*
+
+authfile.c
+
+Author: Tatu Ylonen <ylo@cs.hut.fi>
+
+Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ All rights reserved
+
+Created: Mon Mar 27 03:52:05 1995 ylo
+
+This file contains functions for reading and writing identity files, and
+for reading the passphrase from the user.
+
+*/
+
+#include "includes.h"
+RCSID("$Id: authfile.c,v 1.1 1999/10/27 03:42:43 damien Exp $");
+
+#include <openssl/bn.h>
+#include "xmalloc.h"
+#include "buffer.h"
+#include "bufaux.h"
+#include "cipher.h"
+#include "ssh.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(const char *filename, const char *passphrase,
+ RSA *key, const char *comment)
+{
+ Buffer buffer, encrypted;
+ char buf[100], *cp;
+ int f, 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, 1);
+ 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);
+
+ /* Write to a file. */
+ f = open(filename, O_WRONLY|O_CREAT|O_TRUNC, 0600);
+ if (f < 0)
+ return 0;
+
+ if (write(f, buffer_ptr(&encrypted), buffer_len(&encrypted)) !=
+ buffer_len(&encrypted))
+ {
+ debug("Write to key file %.200s failed: %.100s", filename,
+ strerror(errno));
+ buffer_free(&encrypted);
+ close(f);
+ remove(filename);
+ return 0;
+ }
+ close(f);
+ buffer_free(&encrypted);
+ return 1;
+}
+
+/* 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(const char *filename, RSA *pub,
+ char **comment_return)
+{
+ int f, i;
+ off_t len;
+ Buffer buffer;
+ char *cp;
+
+ /* Read data from the file into the buffer. */
+ f = open(filename, O_RDONLY);
+ if (f < 0)
+ return 0;
+
+ len = lseek(f, (off_t)0, SEEK_END);
+ lseek(f, (off_t)0, SEEK_SET);
+
+ buffer_init(&buffer);
+ buffer_append_space(&buffer, &cp, len);
+
+ if (read(f, cp, (size_t)len) != (size_t)len)
+ {
+ debug("Read from key file %.200s failed: %.100s", filename,
+ strerror(errno));
+ buffer_free(&buffer);
+ close(f);
+ return 0;
+ }
+ close(f);
+
+ /* 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;
+ }
+
+ /* 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);
+ pub->n = BN_new();
+ buffer_get_bignum(&buffer, pub->n);
+ 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;
+}
+
+/* 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. */
+
+int
+load_private_key(const char *filename, const char *passphrase,
+ RSA *prv, char **comment_return)
+{
+ int f, i, check1, check2, cipher_type;
+ off_t len;
+ Buffer buffer, decrypted;
+ char *cp;
+ CipherContext cipher;
+ BN_CTX *ctx;
+ BIGNUM *aux;
+ struct stat st;
+
+ /* Read the file into the buffer. */
+ f = open(filename, O_RDONLY);
+ if (f < 0)
+ return 0;
+
+ /* We assume we are called under uid of the owner of the file */
+ if (fstat(f, &st) < 0 ||
+ (st.st_uid != 0 && st.st_uid != getuid()) ||
+ (st.st_mode & 077) != 0) {
+ 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;
+ }
+
+ len = lseek(f, (off_t)0, SEEK_END);
+ lseek(f, (off_t)0, SEEK_SET);
+
+ buffer_init(&buffer);
+ buffer_append_space(&buffer, &cp, len);
+
+ if (read(f, cp, (size_t)len) != (size_t)len)
+ {
+ debug("Read from key file %.200s failed: %.100s", filename,
+ strerror(errno));
+ buffer_free(&buffer);
+ close(f);
+ return 0;
+ }
+ close(f);
+
+ /* 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_mask() | 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, 0);
+ 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);
+ BN_clear_free(prv->e);
+ 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;
+}