packetstorm sync

1 files changed, 464 insertions, 0 deletions

diff --git a/other/openssh-reverse/cipher.c b/other/openssh-reverse/cipher.c
new file mode 100644
index 0000000..a44e51d
--- /dev/null
+++ b/other/openssh-reverse/cipher.c
@@ -0,0 +1,464 @@
+/*
+ *
+ * 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("$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>
+
+/*
+ * This is used by SSH1:
+ *
+ * What kind of triple DES are these 2 routines?
+ *
+ * Why is there a redundant initialization vector?
+ *
+ * If only iv3 was used, then, this would till effect have been
+ * outer-cbc. However, there is also a private iv1 == iv2 which
+ * perhaps makes differential analysis easier. On the other hand, the
+ * private iv1 probably makes the CRC-32 attack ineffective. This is a
+ * result of that there is no longer any known iv1 to use when
+ * choosing the X block.
+ */
+void
+SSH_3CBC_ENCRYPT(des_key_schedule ks1,
+                 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;
+
+        memcpy(&iv1, iv2, 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, 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,
+                 unsigned char *dest, unsigned char *src,
+                 unsigned int len)
+{
+        des_cblock iv1;
+
+        memcpy(&iv1, iv2, 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, ks1, &iv1, DES_DECRYPT);
+        /* memcpy(&iv1, iv2, 8); */
+        /* Note how iv1 == iv2 on entry and exit. */
+}
+
+/*
+ * SSH1 uses a variation on Blowfish, all bytes must be swapped before
+ * and after encryption/decryption. Thus the swap_bytes stuff (yuk).
+ */
+static void
+swap_bytes(const unsigned char *src, unsigned char *dst_, int n)
+{
+        /* 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 in cipher.h.
+ */
+static char *cipher_names[] =
+{
+        "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.
+ */
+
+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_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)
+{
+        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)
+{
+        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.
+ */
+
+int
+cipher_number(const char *name)
+{
+        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.
+ */
+
+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);
+
+        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)
+{
+        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)
+{
+        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)
+{
+        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));
+        }
+}