7 files changed, 109 insertions, 70 deletions

diff --git a/ChangeLog b/ChangeLog
index 4ca8825a7..2716f7872 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -13,6 +13,10 @@
      [channels.h session.c ssh.c]
      increase the SSH v2 window size to 4 packets. comsumes a little
      bit more memory for slow receivers but increases througput.
+   - markus@cvs.openbsd.org 2002/02/14 23:41:01
+     [authfile.c cipher.c cipher.h kex.c kex.h packet.c]
+     hide some more implementation details of cipher.[ch] and prepares for move
+     to EVP, ok deraadt@
 
 20020218
  - (tim) newer config.guess from ftp://ftp.gnu.org/gnu/config/config.guess
@@ -7610,4 +7614,4 @@
  - Wrote replacements for strlcpy and mkdtemp
  - Released 1.0pre1
 
-$Id: ChangeLog,v 1.1857 2002/02/19 04:20:57 djm Exp $
+$Id: ChangeLog,v 1.1858 2002/02/19 04:21:23 djm Exp $
diff --git a/authfile.c b/authfile.c
index 69e0da03b..e35714e93 100644
--- a/authfile.c
+++ b/authfile.c
@@ -36,7 +36,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: authfile.c,v 1.45 2001/12/29 21:56:01 stevesk Exp $");
+RCSID("$OpenBSD: authfile.c,v 1.46 2002/02/14 23:41:01 markus Exp $");
 
 #include <openssl/err.h>
 #include <openssl/evp.h>
@@ -69,7 +69,7 @@ key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
 {
         Buffer buffer, encrypted;
         u_char buf[100], *cp;
-        int fd, i;
+        int fd, i, cipher_num;
         CipherContext ciphercontext;
         Cipher *cipher;
         u_int32_t rand;
@@ -78,11 +78,9 @@ key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
          * 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 = cipher_by_number(SSH_CIPHER_NONE);
-        else
-                cipher = cipher_by_number(SSH_AUTHFILE_CIPHER);
-        if (cipher == NULL)
+        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. */
@@ -119,7 +117,7 @@ key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
         buffer_put_char(&encrypted, 0);
 
         /* Store cipher type. */
-        buffer_put_char(&encrypted, cipher->number);
+        buffer_put_char(&encrypted, cipher_num);
         buffer_put_int(&encrypted, 0);  /* For future extension */
 
         /* Store public key.  This will be in plain text. */
@@ -131,9 +129,11 @@ key_save_private_rsa1(Key *key, const char *filename, const char *passphrase,
         /* 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(&ciphercontext, cp,
+        cipher_set_key_string(&ciphercontext, cipher, passphrase,
+            CIPHER_ENCRYPT);
+        cipher_crypt(&ciphercontext, cp,
             buffer_ptr(&buffer), buffer_len(&buffer));
+        cipher_cleanup(&ciphercontext);
         memset(&ciphercontext, 0, sizeof(ciphercontext));
 
         /* Destroy temporary data. */
@@ -380,9 +380,11 @@ key_load_private_rsa1(int fd, const char *filename, const char *passphrase,
         cp = buffer_append_space(&decrypted, buffer_len(&buffer));
 
         /* Rest of the buffer is encrypted.  Decrypt it using the passphrase. */
-        cipher_set_key_string(&ciphercontext, cipher, passphrase);
-        cipher_decrypt(&ciphercontext, cp,
+        cipher_set_key_string(&ciphercontext, cipher, passphrase,
+            CIPHER_DECRYPT);
+        cipher_crypt(&ciphercontext, cp,
             buffer_ptr(&buffer), buffer_len(&buffer));
+        cipher_cleanup(&ciphercontext);
         memset(&ciphercontext, 0, sizeof(ciphercontext));
         buffer_free(&buffer);
 
diff --git a/cipher.c b/cipher.c
index 58b0e8aa7..c31696cee 100644
--- a/cipher.c
+++ b/cipher.c
@@ -35,7 +35,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: cipher.c,v 1.50 2002/01/21 22:30:12 markus Exp $");
+RCSID("$OpenBSD: cipher.c,v 1.51 2002/02/14 23:41:01 markus Exp $");
 
 #include "xmalloc.h"
 #include "log.h"
@@ -43,6 +43,17 @@ RCSID("$OpenBSD: cipher.c,v 1.50 2002/01/21 22:30:12 markus Exp $");
 
 #include <openssl/md5.h>
 
+struct Cipher {
+        char    *name;
+        int     number;         /* for ssh1 only */
+        u_int   block_size;
+        u_int   key_len;
+        void    (*setkey)(CipherContext *, const u_char *, u_int);
+        void    (*setiv)(CipherContext *, const u_char *, u_int);
+        void    (*encrypt)(CipherContext *, u_char *, const u_char *, u_int);
+        void    (*decrypt)(CipherContext *, u_char *, const u_char *, u_int);
+};
+
 /* no encryption */
 static void
 none_setkey(CipherContext *cc, const u_char *key, u_int keylen)
@@ -397,6 +408,18 @@ Cipher ciphers[] = {
 
 /*--*/
 
+u_int   
+cipher_blocksize(Cipher *c)
+{
+        return (c->block_size);
+}
+
+u_int   
+cipher_keylen(Cipher *c)
+{
+        return (c->key_len);
+}
+
 u_int
 cipher_mask_ssh1(int client)
 {
@@ -479,8 +502,8 @@ cipher_name(int id)
 }
 
 void
-cipher_init(CipherContext *cc, Cipher *cipher,
-    const u_char *key, u_int keylen, const u_char *iv, u_int ivlen)
+cipher_init(CipherContext *cc, Cipher *cipher, const u_char *key,
+     u_int keylen, const u_char *iv, u_int ivlen, int encrypt)
 {
         if (keylen < cipher->key_len)
                 fatal("cipher_init: key length %d is insufficient for %s.",
@@ -489,24 +512,26 @@ cipher_init(CipherContext *cc, Cipher *cipher,
                 fatal("cipher_init: iv length %d is insufficient for %s.",
                     ivlen, cipher->name);
         cc->cipher = cipher;
+        cc->encrypt = (encrypt == CIPHER_ENCRYPT);
         cipher->setkey(cc, key, keylen);
         cipher->setiv(cc, iv, ivlen);
 }
 
 void
-cipher_encrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
+cipher_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
 {
         if (len % cc->cipher->block_size)
                 fatal("cipher_encrypt: bad plaintext length %d", len);
-        cc->cipher->encrypt(cc, dest, src, len);
+        if (cc->encrypt)
+                cc->cipher->encrypt(cc, dest, src, len);
+        else
+                cc->cipher->decrypt(cc, dest, src, len);
 }
 
 void
-cipher_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
+cipher_cleanup(CipherContext *cc)
 {
-        if (len % cc->cipher->block_size)
-                fatal("cipher_decrypt: bad ciphertext length %d", len);
-        cc->cipher->decrypt(cc, dest, src, len);
+        memset(cc, 0, sizeof(*cc));
 }
 
 /*
@@ -516,7 +541,7 @@ cipher_decrypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
 
 void
 cipher_set_key_string(CipherContext *cc, Cipher *cipher,
-    const char *passphrase)
+    const char *passphrase, int encrypt)
 {
         MD5_CTX md;
         u_char digest[16];
@@ -525,7 +550,7 @@ cipher_set_key_string(CipherContext *cc, Cipher *cipher,
         MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
         MD5_Final(digest, &md);
 
-        cipher_init(cc, cipher, digest, 16, NULL, 0);
+        cipher_init(cc, cipher, digest, 16, NULL, 0, encrypt);
 
         memset(digest, 0, sizeof(digest));
         memset(&md, 0, sizeof(md));
diff --git a/cipher.h b/cipher.h
index 4533f5e4c..0c412b47f 100644
--- a/cipher.h
+++ b/cipher.h
@@ -32,7 +32,7 @@
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-/* RCSID("$OpenBSD: cipher.h,v 1.29 2001/08/23 11:31:59 markus Exp $"); */
+/* RCSID("$OpenBSD: cipher.h,v 1.30 2002/02/14 23:41:01 markus Exp $"); */
 
 #ifndef CIPHER_H
 #define CIPHER_H
@@ -59,9 +59,13 @@
 #define SSH_CIPHER_RESERVED     7
 #define SSH_CIPHER_MAX          31
 
+#define CIPHER_ENCRYPT          1
+#define CIPHER_DECRYPT          0
+
 typedef struct Cipher Cipher;
 typedef struct CipherContext CipherContext;
 
+struct Cipher;
 struct CipherContext {
         union {
                 struct {
@@ -91,18 +95,10 @@ struct CipherContext {
                 } rijndael;
                 RC4_KEY rc4;
         }       u;
+        int     plaintext;
+        int     encrypt;
         Cipher *cipher;
 };
-struct Cipher {
-        char    *name;
-        int     number;         /* for ssh1 only */
-        u_int   block_size;
-        u_int   key_len;
-        void    (*setkey)(CipherContext *, const u_char *, u_int);
-        void    (*setiv)(CipherContext *, const u_char *, u_int);
-        void    (*encrypt)(CipherContext *, u_char *, const u_char *, u_int);
-        void    (*decrypt)(CipherContext *, u_char *, const u_char *, u_int);
-};
 
 u_int    cipher_mask_ssh1(int);
 Cipher  *cipher_by_name(const char *);
@@ -111,9 +107,10 @@ int	 cipher_number(const char *);
 char    *cipher_name(int);
 int      ciphers_valid(const char *);
 void     cipher_init(CipherContext *, Cipher *, const u_char *, u_int,
-    const u_char *, u_int);
-void     cipher_encrypt(CipherContext *, u_char *, const u_char *, u_int);
-void     cipher_decrypt(CipherContext *, u_char *, const u_char *, u_int);
-void     cipher_set_key_string(CipherContext *, Cipher *, const char *);
-
+    const u_char *, u_int, int);
+void     cipher_crypt(CipherContext *, u_char *, const u_char *, u_int);
+void     cipher_cleanup(CipherContext *);
+void     cipher_set_key_string(CipherContext *, Cipher *, const char *, int);
+u_int    cipher_blocksize(Cipher *);
+u_int    cipher_keylen(Cipher *);
 #endif                          /* CIPHER_H */
diff --git a/kex.c b/kex.c
index 02c9780ad..e9f944b05 100644
--- a/kex.c
+++ b/kex.c
@@ -23,7 +23,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: kex.c,v 1.44 2002/02/11 16:10:15 markus Exp $");
+RCSID("$OpenBSD: kex.c,v 1.45 2002/02/14 23:41:01 markus Exp $");
 
 #include <openssl/crypto.h>
 
@@ -232,13 +232,14 @@ choose_enc(Enc *enc, char *client, char *server)
         char *name = match_list(client, server, NULL);
         if (name == NULL)
                 fatal("no matching cipher found: client %s server %s", client, server);
-        enc->cipher = cipher_by_name(name);
-        if (enc->cipher == NULL)
+        if ((enc->cipher = cipher_by_name(name)) == NULL)
                 fatal("matching cipher is not supported: %s", name);
         enc->name = name;
         enc->enabled = 0;
         enc->iv = NULL;
         enc->key = NULL;
+        enc->key_len = cipher_keylen(enc->cipher);
+        enc->block_size = cipher_blocksize(enc->cipher);
 }
 static void
 choose_mac(Mac *mac, char *client, char *server)
@@ -341,10 +342,10 @@ kex_choose_conf(Kex *kex)
         need = 0;
         for (mode = 0; mode < MODE_MAX; mode++) {
                 newkeys = kex->newkeys[mode];
-                if (need < newkeys->enc.cipher->key_len)
-                        need = newkeys->enc.cipher->key_len;
-                if (need < newkeys->enc.cipher->block_size)
-                        need = newkeys->enc.cipher->block_size;
+                if (need < newkeys->enc.key_len)
+                        need = newkeys->enc.key_len;
+                if (need < newkeys->enc.block_size)
+                        need = newkeys->enc.block_size;
                 if (need < newkeys->mac.key_len)
                         need = newkeys->mac.key_len;
         }
diff --git a/kex.h b/kex.h
index 7bd6bc215..755bf332a 100644
--- a/kex.h
+++ b/kex.h
@@ -1,4 +1,4 @@
-/*      $OpenBSD: kex.h,v 1.28 2001/12/28 15:06:00 markus Exp $ */
+/*      $OpenBSD: kex.h,v 1.29 2002/02/14 23:41:01 markus Exp $ */
 
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
@@ -71,6 +71,8 @@ struct Enc {
         char    *name;
         Cipher  *cipher;
         int     enabled;
+        u_int   key_len;
+        u_int   block_size;
         u_char  *key;
         u_char  *iv;
 };
diff --git a/packet.c b/packet.c
index e334c4b69..794659b8a 100644
--- a/packet.c
+++ b/packet.c
@@ -37,7 +37,7 @@
  */
 
 #include "includes.h"
-RCSID("$OpenBSD: packet.c,v 1.87 2002/01/24 21:13:23 stevesk Exp $");
+RCSID("$OpenBSD: packet.c,v 1.88 2002/02/14 23:41:01 markus Exp $");
 
 #include "xmalloc.h"
 #include "buffer.h"
@@ -131,8 +131,8 @@ packet_set_connection(int fd_in, int fd_out)
                 fatal("packet_set_connection: cannot load cipher 'none'");
         connection_in = fd_in;
         connection_out = fd_out;
-        cipher_init(&send_context, none, "", 0, NULL, 0);
-        cipher_init(&receive_context, none, "", 0, NULL, 0);
+        cipher_init(&send_context, none, "", 0, NULL, 0, CIPHER_ENCRYPT);
+        cipher_init(&receive_context, none, "", 0, NULL, 0, CIPHER_DECRYPT);
         newkeys[MODE_IN] = newkeys[MODE_OUT] = NULL;
         if (!initialized) {
                 initialized = 1;
@@ -241,6 +241,8 @@ packet_close(void)
                 buffer_free(&compression_buffer);
                 buffer_compress_uninit();
         }
+        cipher_cleanup(&send_context);
+        cipher_cleanup(&receive_context);
 }
 
 /* Sets remote side protocol flags. */
@@ -298,8 +300,8 @@ packet_set_encryption_key(const u_char *key, u_int keylen,
                 fatal("packet_set_encryption_key: unknown cipher number %d", number);
         if (keylen < 20)
                 fatal("packet_set_encryption_key: keylen too small: %d", keylen);
-        cipher_init(&receive_context, cipher, key, keylen, NULL, 0);
-        cipher_init(&send_context, cipher, key, keylen, NULL, 0);
+        cipher_init(&send_context, cipher, key, keylen, NULL, 0, CIPHER_ENCRYPT);
+        cipher_init(&receive_context, cipher, key, keylen, NULL, 0, CIPHER_DECRYPT);
 }
 
 /* Start constructing a packet to send. */
@@ -388,7 +390,7 @@ packet_send1(void)
 
         /* Insert padding. Initialized to zero in packet_start1() */
         padding = 8 - len % 8;
-        if (send_context.cipher->number != SSH_CIPHER_NONE) {
+        if (!send_context.plaintext) {
                 cp = buffer_ptr(&outgoing_packet);
                 for (i = 0; i < padding; i++) {
                         if (i % 4 == 0)
@@ -414,7 +416,7 @@ packet_send1(void)
         PUT_32BIT(buf, len);
         buffer_append(&output, buf, 4);
         cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
-        cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
+        cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
             buffer_len(&outgoing_packet));
 
 #ifdef PACKET_DEBUG
@@ -438,14 +440,20 @@ set_newkeys(int mode)
         Mac *mac;
         Comp *comp;
         CipherContext *cc;
+        int encrypt;
 
         debug("newkeys: mode %d", mode);
 
-        cc = (mode == MODE_OUT) ? &send_context : &receive_context;
+        if (mode == MODE_OUT) {
+                cc = &send_context;
+                encrypt = CIPHER_ENCRYPT;
+        } else {
+                cc = &receive_context;
+                encrypt = CIPHER_DECRYPT;
+        }
         if (newkeys[mode] != NULL) {
                 debug("newkeys: rekeying");
-                /* todo: free old keys, reset compression/cipher-ctxt; */
-                memset(cc, 0, sizeof(*cc));
+                cipher_cleanup(cc);
                 enc  = &newkeys[mode]->enc;
                 mac  = &newkeys[mode]->mac;
                 comp = &newkeys[mode]->comp;
@@ -467,10 +475,10 @@ set_newkeys(int mode)
         if (mac->md != NULL)
                 mac->enabled = 1;
         DBG(debug("cipher_init_context: %d", mode));
-        cipher_init(cc, enc->cipher, enc->key, enc->cipher->key_len,
-            enc->iv, enc->cipher->block_size);
-        memset(enc->iv,  0, enc->cipher->block_size);
-        memset(enc->key, 0, enc->cipher->key_len);
+        cipher_init(cc, enc->cipher, enc->key, enc->key_len,
+            enc->iv, enc->block_size, encrypt);
+        memset(enc->iv,  0, enc->block_size);
+        memset(enc->key, 0, enc->key_len);
         if (comp->type != 0 && comp->enabled == 0) {
                 packet_init_compression();
                 if (mode == MODE_OUT)
@@ -504,7 +512,7 @@ packet_send2(void)
                 mac  = &newkeys[MODE_OUT]->mac;
                 comp = &newkeys[MODE_OUT]->comp;
         }
-        block_size = enc ? enc->cipher->block_size : 8;
+        block_size = enc ? enc->block_size : 8;
 
         ucp = buffer_ptr(&outgoing_packet);
         type = ucp[5];
@@ -548,7 +556,7 @@ packet_send2(void)
                 extra_pad = 0;
         }
         cp = buffer_append_space(&outgoing_packet, padlen);
-        if (enc && enc->cipher->number != SSH_CIPHER_NONE) {
+        if (enc && !send_context.plaintext) {
                 /* random padding */
                 for (i = 0; i < padlen; i++) {
                         if (i % 4 == 0)
@@ -576,7 +584,7 @@ packet_send2(void)
         }
         /* encrypt packet and append to output buffer. */
         cp = buffer_append_space(&output, buffer_len(&outgoing_packet));
-        cipher_encrypt(&send_context, cp, buffer_ptr(&outgoing_packet),
+        cipher_crypt(&send_context, cp, buffer_ptr(&outgoing_packet),
             buffer_len(&outgoing_packet));
         /* append unencrypted MAC */
         if (mac && mac->enabled)
@@ -729,14 +737,14 @@ packet_read_poll1(void)
          * (C)1998 CORE-SDI, Buenos Aires Argentina
          * Ariel Futoransky(futo@core-sdi.com)
          */
-        if (receive_context.cipher->number != SSH_CIPHER_NONE &&
+        if (!receive_context.plaintext &&
             detect_attack(buffer_ptr(&input), padded_len, NULL) == DEATTACK_DETECTED)
                 packet_disconnect("crc32 compensation attack: network attack detected");
 
         /* Decrypt data to incoming_packet. */
         buffer_clear(&incoming_packet);
         cp = buffer_append_space(&incoming_packet, padded_len);
-        cipher_decrypt(&receive_context, cp, buffer_ptr(&input), padded_len);
+        cipher_crypt(&receive_context, cp, buffer_ptr(&input), padded_len);
 
         buffer_consume(&input, padded_len);
 
@@ -793,7 +801,7 @@ packet_read_poll2(u_int32_t *seqnr_p)
                 comp = &newkeys[MODE_IN]->comp;
         }
         maclen = mac && mac->enabled ? mac->mac_len : 0;
-        block_size = enc ? enc->cipher->block_size : 8;
+        block_size = enc ? enc->block_size : 8;
 
         if (packet_length == 0) {
                 /*
@@ -804,7 +812,7 @@ packet_read_poll2(u_int32_t *seqnr_p)
                         return SSH_MSG_NONE;
                 buffer_clear(&incoming_packet);
                 cp = buffer_append_space(&incoming_packet, block_size);
-                cipher_decrypt(&receive_context, cp, buffer_ptr(&input),
+                cipher_crypt(&receive_context, cp, buffer_ptr(&input),
                     block_size);
                 ucp = buffer_ptr(&incoming_packet);
                 packet_length = GET_32BIT(ucp);
@@ -833,7 +841,7 @@ packet_read_poll2(u_int32_t *seqnr_p)
         buffer_dump(&input);
 #endif
         cp = buffer_append_space(&incoming_packet, need);
-        cipher_decrypt(&receive_context, cp, buffer_ptr(&input), need);
+        cipher_crypt(&receive_context, cp, buffer_ptr(&input), need);
         buffer_consume(&input, need);
         /*
          * compute MAC over seqnr and packet,