/*
-
-cipher.c
-
-Author: Tatu Ylonen <ylo@cs.hut.fi>
-
-Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
- All rights reserved
-
-Created: Wed Apr 19 17:41:39 1995 ylo
-
-*/
+ *
+ * cipher.c
+ *
+ * Author: Tatu Ylonen <ylo@cs.hut.fi>
+ *
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
+ * All rights reserved
+ *
+ * Created: Wed Apr 19 17:41:39 1995 ylo
+ *
+ */
#include "includes.h"
-RCSID("$Id$");
+RCSID("$OpenBSD: cipher.c,v 1.29 2000/07/10 16:30:25 ho Exp $");
#include "ssh.h"
#include "cipher.h"
+#include "xmalloc.h"
#include <openssl/md5.h>
/*
- * What kind of tripple DES are these 2 routines?
+ * This is used by SSH1:
+ *
+ * What kind of triple DES are these 2 routines?
*
* Why is there a redundant initialization vector?
*
*/
void
SSH_3CBC_ENCRYPT(des_key_schedule ks1,
- des_key_schedule ks2, des_cblock *iv2,
- des_key_schedule ks3, des_cblock *iv3,
- void *dest, void *src,
+ des_key_schedule ks2, des_cblock * iv2,
+ des_key_schedule ks3, des_cblock * iv3,
+ unsigned char *dest, unsigned char *src,
unsigned int len)
{
- des_cblock iv1;
+ des_cblock iv1;
- memcpy(&iv1, iv2, 8);
+ memcpy(&iv1, iv2, 8);
- des_cbc_encrypt(src, dest, len, ks1, &iv1, DES_ENCRYPT);
- memcpy(&iv1, dest + len - 8, 8);
+ des_cbc_encrypt(src, dest, len, ks1, &iv1, DES_ENCRYPT);
+ memcpy(&iv1, dest + len - 8, 8);
- des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_DECRYPT);
- memcpy(iv2, &iv1, 8); /* Note how iv1 == iv2 on entry and exit. */
+ des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_DECRYPT);
+ memcpy(iv2, &iv1, 8); /* Note how iv1 == iv2 on entry and exit. */
- des_cbc_encrypt(dest, dest, len, ks3, iv3, DES_ENCRYPT);
- memcpy(iv3, dest + len - 8, 8);
+ des_cbc_encrypt(dest, dest, len, ks3, iv3, DES_ENCRYPT);
+ memcpy(iv3, dest + len - 8, 8);
}
void
SSH_3CBC_DECRYPT(des_key_schedule ks1,
- des_key_schedule ks2, des_cblock *iv2,
- des_key_schedule ks3, des_cblock *iv3,
- void *dest, void *src,
+ des_key_schedule ks2, des_cblock * iv2,
+ des_key_schedule ks3, des_cblock * iv3,
+ unsigned char *dest, unsigned char *src,
unsigned int len)
{
- des_cblock iv1;
+ des_cblock iv1;
- memcpy(&iv1, iv2, 8);
+ memcpy(&iv1, iv2, 8);
- des_cbc_encrypt(src, dest, len, ks3, iv3, DES_DECRYPT);
- memcpy(iv3, src + len - 8, 8);
+ des_cbc_encrypt(src, dest, len, ks3, iv3, DES_DECRYPT);
+ memcpy(iv3, src + len - 8, 8);
- des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_ENCRYPT);
- memcpy(iv2, dest + len - 8, 8);
+ des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_ENCRYPT);
+ memcpy(iv2, dest + len - 8, 8);
- des_cbc_encrypt(dest, dest, len, ks1, &iv1, DES_DECRYPT);
- /* memcpy(&iv1, iv2, 8); */ /* Note how iv1 == iv2 on entry and exit. */
+ des_cbc_encrypt(dest, dest, len, ks1, &iv1, DES_DECRYPT);
+ /* memcpy(&iv1, iv2, 8); */
+ /* Note how iv1 == iv2 on entry and exit. */
}
/*
- * SSH uses a variation on Blowfish, all bytes must be swapped before
+ * SSH1 uses a variation on Blowfish, all bytes must be swapped before
* and after encryption/decryption. Thus the swap_bytes stuff (yuk).
*/
-static
-void
+static void
swap_bytes(const unsigned char *src, unsigned char *dst_, int n)
{
- u_int32_t *dst = (u_int32_t *)dst_; /* dst must be properly aligned. */
- union {
- u_int32_t i;
- char c[4];
- } t;
-
- /* assert((n & 7) == 0); */
-
- /* Process 8 bytes every lap. */
- for (n = n / 8; n > 0; n--)
- {
- t.c[3] = *src++;
- t.c[2] = *src++;
- t.c[1] = *src++;
- t.c[0] = *src++;
- *dst++ = t.i;
-
- t.c[3] = *src++;
- t.c[2] = *src++;
- t.c[1] = *src++;
- t.c[0] = *src++;
- *dst++ = t.i;
- }
-}
-
-void (*cipher_attack_detected)(const char *fmt, ...) = fatal;
-
-static inline
-void
-detect_cbc_attack(const unsigned char *src,
- unsigned int len)
-{
- return;
-
- log("CRC-32 CBC insertion attack detected");
- cipher_attack_detected("CRC-32 CBC insertion attack detected");
+ /* dst must be properly aligned. */
+ u_int32_t *dst = (u_int32_t *) dst_;
+ union {
+ u_int32_t i;
+ char c[4];
+ } t;
+
+ /* Process 8 bytes every lap. */
+ for (n = n / 8; n > 0; n--) {
+ t.c[3] = *src++;
+ t.c[2] = *src++;
+ t.c[1] = *src++;
+ t.c[0] = *src++;
+ *dst++ = t.i;
+
+ t.c[3] = *src++;
+ t.c[2] = *src++;
+ t.c[1] = *src++;
+ t.c[0] = *src++;
+ *dst++ = t.i;
+ }
}
-/* Names of all encryption algorithms. These must match the numbers defined
- int cipher.h. */
+/*
+ * Names of all encryption algorithms.
+ * These must match the numbers defined in cipher.h.
+ */
static char *cipher_names[] =
{
- "none",
- "idea",
- "des",
- "3des",
- "tss",
- "rc4",
- "blowfish"
+ "none",
+ "idea",
+ "des",
+ "3des",
+ "tss",
+ "rc4",
+ "blowfish",
+ "reserved",
+ "blowfish-cbc",
+ "3des-cbc",
+ "arcfour",
+ "cast128-cbc"
};
-/* Returns a bit mask indicating which ciphers are supported by this
- implementation. The bit mask has the corresponding bit set of each
- supported cipher. */
+/*
+ * Returns a bit mask indicating which ciphers are supported by this
+ * implementation. The bit mask has the corresponding bit set of each
+ * supported cipher.
+ */
-unsigned int cipher_mask()
+unsigned int
+cipher_mask1()
+{
+ unsigned int mask = 0;
+ mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
+ mask |= 1 << SSH_CIPHER_BLOWFISH;
+ return mask;
+}
+unsigned int
+cipher_mask2()
{
- unsigned int mask = 0;
- mask |= 1 << SSH_CIPHER_3DES; /* Mandatory */
- mask |= 1 << SSH_CIPHER_BLOWFISH;
- return mask;
+ unsigned int mask = 0;
+ mask |= 1 << SSH_CIPHER_BLOWFISH_CBC;
+ mask |= 1 << SSH_CIPHER_3DES_CBC;
+ mask |= 1 << SSH_CIPHER_ARCFOUR;
+ mask |= 1 << SSH_CIPHER_CAST128_CBC;
+ return mask;
+}
+unsigned int
+cipher_mask()
+{
+ return cipher_mask1() | cipher_mask2();
}
/* Returns the name of the cipher. */
-const
-char *cipher_name(int cipher)
+const char *
+cipher_name(int cipher)
+{
+ if (cipher < 0 || cipher >= sizeof(cipher_names) / sizeof(cipher_names[0]) ||
+ cipher_names[cipher] == NULL)
+ fatal("cipher_name: bad cipher name: %d", cipher);
+ return cipher_names[cipher];
+}
+
+/* Returns 1 if the name of the ciphers are valid. */
+
+#define CIPHER_SEP ","
+int
+ciphers_valid(const char *names)
{
- if (cipher < 0 || cipher >= sizeof(cipher_names) / sizeof(cipher_names[0]) ||
- cipher_names[cipher] == NULL)
- fatal("cipher_name: bad cipher number: %d", cipher);
- return cipher_names[cipher];
+ char *ciphers, *cp;
+ char *p;
+ int i;
+
+ if (names == NULL || strcmp(names, "") == 0)
+ return 0;
+ ciphers = cp = xstrdup(names);
+ for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
+ (p = strsep(&cp, CIPHER_SEP))) {
+ i = cipher_number(p);
+ if (i == -1 || !(cipher_mask2() & (1 << i))) {
+ xfree(ciphers);
+ return 0;
+ }
+ }
+ xfree(ciphers);
+ return 1;
}
-/* Parses the name of the cipher. Returns the number of the corresponding
- cipher, or -1 on error. */
+/*
+ * Parses the name of the cipher. Returns the number of the corresponding
+ * cipher, or -1 on error.
+ */
int
cipher_number(const char *name)
{
- int i;
- for (i = 0; i < sizeof(cipher_names) / sizeof(cipher_names[0]); i++)
- if (strcmp(cipher_names[i], name) == 0 &&
- (cipher_mask() & (1 << i)))
- return i;
- return -1;
+ int i;
+ if (name == NULL)
+ return -1;
+ for (i = 0; i < sizeof(cipher_names) / sizeof(cipher_names[0]); i++)
+ if (strcmp(cipher_names[i], name) == 0 &&
+ (cipher_mask() & (1 << i)))
+ return i;
+ return -1;
}
-/* Selects the cipher, and keys if by computing the MD5 checksum of the
- passphrase and using the resulting 16 bytes as the key. */
+/*
+ * Selects the cipher, and keys if by computing the MD5 checksum of the
+ * passphrase and using the resulting 16 bytes as the key.
+ */
-void cipher_set_key_string(CipherContext *context, int cipher,
- const char *passphrase, int for_encryption)
+void
+cipher_set_key_string(CipherContext *context, int cipher, const char *passphrase)
{
- MD5_CTX md;
- unsigned char digest[16];
-
- MD5_Init(&md);
- MD5_Update(&md, (const unsigned char *)passphrase, strlen(passphrase));
- MD5_Final(digest, &md);
-
- cipher_set_key(context, cipher, digest, 16, for_encryption);
-
- memset(digest, 0, sizeof(digest));
- memset(&md, 0, sizeof(md));
+ MD5_CTX md;
+ unsigned char digest[16];
+
+ MD5_Init(&md);
+ MD5_Update(&md, (const unsigned char *) passphrase, strlen(passphrase));
+ MD5_Final(digest, &md);
+
+ cipher_set_key(context, cipher, digest, 16);
+
+ memset(digest, 0, sizeof(digest));
+ memset(&md, 0, sizeof(md));
}
/* Selects the cipher to use and sets the key. */
-void cipher_set_key(CipherContext *context, int cipher,
- const unsigned char *key, int keylen, int for_encryption)
+void
+cipher_set_key(CipherContext *context, int cipher, const unsigned char *key,
+ int keylen)
{
- unsigned char padded[32];
-
- /* Set cipher type. */
- context->type = cipher;
-
- /* Get 32 bytes of key data. Pad if necessary. (So that code below does
- not need to worry about key size). */
- memset(padded, 0, sizeof(padded));
- memcpy(padded, key, keylen < sizeof(padded) ? keylen : sizeof(padded));
-
- /* Initialize the initialization vector. */
- switch (cipher)
- {
- case SSH_CIPHER_NONE:
- /* Has to stay for authfile saving of private key with no passphrase */
- break;
-
- case SSH_CIPHER_3DES:
- /* Note: the least significant bit of each byte of key is parity,
- and must be ignored by the implementation. 16 bytes of key are
- used (first and last keys are the same). */
- if (keylen < 16)
- error("Key length %d is insufficient for 3DES.", keylen);
- des_set_key((void*)padded, context->u.des3.key1);
- des_set_key((void*)(padded + 8), context->u.des3.key2);
- if (keylen <= 16)
- des_set_key((void*)padded, context->u.des3.key3);
- else
- des_set_key((void*)(padded + 16), context->u.des3.key3);
- memset(context->u.des3.iv2, 0, sizeof(context->u.des3.iv2));
- memset(context->u.des3.iv3, 0, sizeof(context->u.des3.iv3));
- break;
-
- case SSH_CIPHER_BLOWFISH:
- BF_set_key(&context->u.bf.key, keylen, padded);
- memset(context->u.bf.iv, 0, 8);
- break;
-
- default:
- fatal("cipher_set_key: unknown cipher: %d", cipher);
- }
- memset(padded, 0, sizeof(padded));
+ unsigned char padded[32];
+
+ /* Set cipher type. */
+ context->type = cipher;
+
+ /* Get 32 bytes of key data. Pad if necessary. (So that code
+ below does not need to worry about key size). */
+ memset(padded, 0, sizeof(padded));
+ memcpy(padded, key, keylen < sizeof(padded) ? keylen : sizeof(padded));
+
+ /* Initialize the initialization vector. */
+ switch (cipher) {
+ case SSH_CIPHER_NONE:
+ /*
+ * Has to stay for authfile saving of private key with no
+ * passphrase
+ */
+ break;
+
+ case SSH_CIPHER_3DES:
+ /*
+ * Note: the least significant bit of each byte of key is
+ * parity, and must be ignored by the implementation. 16
+ * bytes of key are used (first and last keys are the same).
+ */
+ if (keylen < 16)
+ error("Key length %d is insufficient for 3DES.", keylen);
+ des_set_key((void *) padded, context->u.des3.key1);
+ des_set_key((void *) (padded + 8), context->u.des3.key2);
+ if (keylen <= 16)
+ des_set_key((void *) padded, context->u.des3.key3);
+ else
+ des_set_key((void *) (padded + 16), context->u.des3.key3);
+ memset(context->u.des3.iv2, 0, sizeof(context->u.des3.iv2));
+ memset(context->u.des3.iv3, 0, sizeof(context->u.des3.iv3));
+ break;
+
+ case SSH_CIPHER_BLOWFISH:
+ if (keylen < 16)
+ error("Key length %d is insufficient for blowfish.", keylen);
+ BF_set_key(&context->u.bf.key, keylen, padded);
+ memset(context->u.bf.iv, 0, 8);
+ break;
+
+ case SSH_CIPHER_3DES_CBC:
+ case SSH_CIPHER_BLOWFISH_CBC:
+ case SSH_CIPHER_ARCFOUR:
+ case SSH_CIPHER_CAST128_CBC:
+ fatal("cipher_set_key: illegal cipher: %s", cipher_name(cipher));
+ break;
+
+ default:
+ fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher));
+ }
+ memset(padded, 0, sizeof(padded));
+}
+
+void
+cipher_set_key_iv(CipherContext * context, int cipher,
+ const unsigned char *key, int keylen,
+ const unsigned char *iv, int ivlen)
+{
+ /* Set cipher type. */
+ context->type = cipher;
+
+ /* Initialize the initialization vector. */
+ switch (cipher) {
+ case SSH_CIPHER_NONE:
+ break;
+
+ case SSH_CIPHER_3DES:
+ case SSH_CIPHER_BLOWFISH:
+ fatal("cipher_set_key_iv: illegal cipher: %s", cipher_name(cipher));
+ break;
+
+ case SSH_CIPHER_3DES_CBC:
+ if (keylen < 24)
+ error("Key length %d is insufficient for 3des-cbc.", keylen);
+ des_set_key((void *) key, context->u.des3.key1);
+ des_set_key((void *) (key+8), context->u.des3.key2);
+ des_set_key((void *) (key+16), context->u.des3.key3);
+ if (ivlen < 8)
+ error("IV length %d is insufficient for 3des-cbc.", ivlen);
+ memcpy(context->u.des3.iv3, (char *)iv, 8);
+ break;
+
+ case SSH_CIPHER_BLOWFISH_CBC:
+ if (keylen < 16)
+ error("Key length %d is insufficient for blowfish.", keylen);
+ if (ivlen < 8)
+ error("IV length %d is insufficient for blowfish.", ivlen);
+ BF_set_key(&context->u.bf.key, keylen, (unsigned char *)key);
+ memcpy(context->u.bf.iv, (char *)iv, 8);
+ break;
+
+ case SSH_CIPHER_ARCFOUR:
+ if (keylen < 16)
+ error("Key length %d is insufficient for arcfour.", keylen);
+ RC4_set_key(&context->u.rc4, keylen, (unsigned char *)key);
+ break;
+
+ case SSH_CIPHER_CAST128_CBC:
+ if (keylen < 16)
+ error("Key length %d is insufficient for cast128.", keylen);
+ if (ivlen < 8)
+ error("IV length %d is insufficient for cast128.", ivlen);
+ CAST_set_key(&context->u.cast.key, keylen, (unsigned char *) key);
+ memcpy(context->u.cast.iv, (char *)iv, 8);
+ break;
+
+ default:
+ fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher));
+ }
}
/* Encrypts data using the cipher. */
-void cipher_encrypt(CipherContext *context, unsigned char *dest,
- const unsigned char *src, unsigned int len)
+void
+cipher_encrypt(CipherContext *context, unsigned char *dest,
+ const unsigned char *src, unsigned int len)
{
- assert((len & 7) == 0);
-
- switch (context->type)
- {
- case SSH_CIPHER_NONE:
- memcpy(dest, src, len);
- break;
-
- case SSH_CIPHER_3DES:
- SSH_3CBC_ENCRYPT(context->u.des3.key1,
- context->u.des3.key2, &context->u.des3.iv2,
- context->u.des3.key3, &context->u.des3.iv3,
- dest, (void*)src, len);
- break;
-
- case SSH_CIPHER_BLOWFISH:
- swap_bytes(src, dest, len);
- BF_cbc_encrypt(dest, dest, len,
- &context->u.bf.key, context->u.bf.iv, BF_ENCRYPT);
- swap_bytes(dest, dest, len);
- break;
-
- default:
- fatal("cipher_encrypt: unknown cipher: %d", context->type);
- }
+ if ((len & 7) != 0)
+ fatal("cipher_encrypt: bad plaintext length %d", len);
+
+ switch (context->type) {
+ case SSH_CIPHER_NONE:
+ memcpy(dest, src, len);
+ break;
+
+ case SSH_CIPHER_3DES:
+ SSH_3CBC_ENCRYPT(context->u.des3.key1,
+ context->u.des3.key2, &context->u.des3.iv2,
+ context->u.des3.key3, &context->u.des3.iv3,
+ dest, (unsigned char *) src, len);
+ break;
+
+ case SSH_CIPHER_BLOWFISH:
+ swap_bytes(src, dest, len);
+ BF_cbc_encrypt(dest, dest, len,
+ &context->u.bf.key, context->u.bf.iv,
+ BF_ENCRYPT);
+ swap_bytes(dest, dest, len);
+ break;
+
+ case SSH_CIPHER_BLOWFISH_CBC:
+ BF_cbc_encrypt((void *)src, dest, len,
+ &context->u.bf.key, context->u.bf.iv,
+ BF_ENCRYPT);
+ break;
+
+ case SSH_CIPHER_3DES_CBC:
+ des_ede3_cbc_encrypt(src, dest, len,
+ context->u.des3.key1, context->u.des3.key2,
+ context->u.des3.key3, &context->u.des3.iv3, DES_ENCRYPT);
+ break;
+
+ case SSH_CIPHER_ARCFOUR:
+ RC4(&context->u.rc4, len, (unsigned char *)src, dest);
+ break;
+
+ case SSH_CIPHER_CAST128_CBC:
+ CAST_cbc_encrypt(src, dest, len,
+ &context->u.cast.key, context->u.cast.iv, CAST_ENCRYPT);
+ break;
+
+ default:
+ fatal("cipher_encrypt: unknown cipher: %s", cipher_name(context->type));
+ }
}
-
+
/* Decrypts data using the cipher. */
-void cipher_decrypt(CipherContext *context, unsigned char *dest,
- const unsigned char *src, unsigned int len)
+void
+cipher_decrypt(CipherContext *context, unsigned char *dest,
+ const unsigned char *src, unsigned int len)
{
- assert((len & 7) == 0);
-
- switch (context->type)
- {
- case SSH_CIPHER_NONE:
- memcpy(dest, src, len);
- break;
-
- case SSH_CIPHER_3DES:
- /* CRC-32 attack? */
- SSH_3CBC_DECRYPT(context->u.des3.key1,
- context->u.des3.key2, &context->u.des3.iv2,
- context->u.des3.key3, &context->u.des3.iv3,
- dest, (void*)src, len);
- break;
-
- case SSH_CIPHER_BLOWFISH:
- detect_cbc_attack(src, len);
- swap_bytes(src, dest, len);
- BF_cbc_encrypt((void*)dest, dest, len,
- &context->u.bf.key, context->u.bf.iv, BF_DECRYPT);
- swap_bytes(dest, dest, len);
- break;
-
- default:
- fatal("cipher_decrypt: unknown cipher: %d", context->type);
- }
+ if ((len & 7) != 0)
+ fatal("cipher_decrypt: bad ciphertext length %d", len);
+
+ switch (context->type) {
+ case SSH_CIPHER_NONE:
+ memcpy(dest, src, len);
+ break;
+
+ case SSH_CIPHER_3DES:
+ SSH_3CBC_DECRYPT(context->u.des3.key1,
+ context->u.des3.key2, &context->u.des3.iv2,
+ context->u.des3.key3, &context->u.des3.iv3,
+ dest, (unsigned char *) src, len);
+ break;
+
+ case SSH_CIPHER_BLOWFISH:
+ swap_bytes(src, dest, len);
+ BF_cbc_encrypt((void *) dest, dest, len,
+ &context->u.bf.key, context->u.bf.iv,
+ BF_DECRYPT);
+ swap_bytes(dest, dest, len);
+ break;
+
+ case SSH_CIPHER_BLOWFISH_CBC:
+ BF_cbc_encrypt((void *) src, dest, len,
+ &context->u.bf.key, context->u.bf.iv,
+ BF_DECRYPT);
+ break;
+
+ case SSH_CIPHER_3DES_CBC:
+ des_ede3_cbc_encrypt(src, dest, len,
+ context->u.des3.key1, context->u.des3.key2,
+ context->u.des3.key3, &context->u.des3.iv3, DES_DECRYPT);
+ break;
+
+ case SSH_CIPHER_ARCFOUR:
+ RC4(&context->u.rc4, len, (unsigned char *)src, dest);
+ break;
+
+ case SSH_CIPHER_CAST128_CBC:
+ CAST_cbc_encrypt(src, dest, len,
+ &context->u.cast.key, context->u.cast.iv, CAST_DECRYPT);
+ break;
+
+ default:
+ fatal("cipher_decrypt: unknown cipher: %s", cipher_name(context->type));
+ }
}
andersk / openssh.git / blobdiff