From ca77392bd1bde7e42b8254f82ca9b0b569b4f74d Mon Sep 17 00:00:00 2001
From: Matt Johnston <matt@ucc.asn.au>
Date: Tue, 30 Aug 2005 16:58:57 +0000
Subject: [PATCH] - Fixed twofish algorithm naming so it actually works. -
Added support for aes256, twofish256 and sha1-96 - Fixed some debugging
statements
--HG--
extra : convert_revision : 598835dadaddb1e95d4ac99f8a1be4ba51639000
---
common-algo.c | 29 +++++++++++++++++++++++++----
common-kex.c | 15 ++++++---------
options.h | 31 ++++++++++++++++++++++---------
packet.c | 27 +++++++++++++--------------
4 files changed, 66 insertions(+), 36 deletions(-)
diff --git a/common-algo.c b/common-algo.c
index 31902d18..4a8f49c4 100644
--- a/common-algo.c
+++ b/common-algo.c
@@ -32,6 +32,10 @@
/* Mappings for ciphers, parameters are
{&cipher_desc, keysize, blocksize} */
+#ifdef DROPBEAR_AES256_CBC
+static const struct dropbear_cipher dropbear_aes256 =
+ {&aes_desc, 32, 16};
+#endif
#ifdef DROPBEAR_AES128_CBC
static const struct dropbear_cipher dropbear_aes128 =
{&aes_desc, 16, 16};
@@ -40,6 +44,10 @@ static const struct dropbear_cipher dropbear_aes128 =
static const struct dropbear_cipher dropbear_blowfish =
{&blowfish_desc, 16, 8};
#endif
+#ifdef DROPBEAR_TWOFISH256_CBC
+static const struct dropbear_cipher dropbear_twofish256 =
+ {&twofish_desc, 32, 16};
+#endif
#ifdef DROPBEAR_TWOFISH128_CBC
static const struct dropbear_cipher dropbear_twofish128 =
{&twofish_desc, 16, 16};
@@ -60,6 +68,10 @@ const struct dropbear_cipher dropbear_nocipher =
static const struct dropbear_hash dropbear_sha1 =
{&sha1_desc, 20, 20};
#endif
+#ifdef DROPBEAR_SHA1_96_HMAC
+static const struct dropbear_hash dropbear_sha1_96 =
+ {&sha1_desc, 20, 12};
+#endif
#ifdef DROPBEAR_MD5_HMAC
static const struct dropbear_hash dropbear_md5 =
{&md5_desc, 16, 16};
@@ -75,19 +87,28 @@ algo_type sshciphers[] = {
#ifdef DROPBEAR_AES128_CBC
{"aes128-cbc", 0, (void*)&dropbear_aes128, 1},
#endif
+#ifdef DROPBEAR_3DES_CBC
+ {"3des-cbc", 0, (void*)&dropbear_3des, 1},
+#endif
+#ifdef DROPBEAR_AES256_CBC
+ {"aes256-cbc", 0, (void*)&dropbear_aes256, 1},
+#endif
#ifdef DROPBEAR_BLOWFISH_CBC
{"blowfish-cbc", 0, (void*)&dropbear_blowfish, 1},
#endif
-#ifdef DROPBEAR_TWOFISH128_CBC
- {"twofish-cbc", 0, (void*)&dropbear_twofish128, 1},
+#ifdef DROPBEAR_TWOFISH256_CBC
+ {"twofish256-cbc", 0, (void*)&dropbear_twofish256, 1},
#endif
-#ifdef DROPBEAR_3DES_CBC
- {"3des-cbc", 0, (void*)&dropbear_3des, 1},
+#ifdef DROPBEAR_TWOFISH128_CBC
+ {"twofish128-cbc", 0, (void*)&dropbear_twofish128, 1},
#endif
{NULL, 0, NULL, 0}
};
algo_type sshhashes[] = {
+#ifdef DROPBEAR_SHA1_96_HMAC
+ {"hmac-sha1-96", 0, (void*)&dropbear_sha1_96, 1},
+#endif
#ifdef DROPBEAR_SHA1_HMAC
{"hmac-sha1", 0, (void*)&dropbear_sha1, 1},
#endif
diff --git a/common-kex.c b/common-kex.c
index a0c7b7e3..f3253299 100644
--- a/common-kex.c
+++ b/common-kex.c
@@ -622,7 +622,7 @@ static void read_kex_algos() {
erralgo = "enc c->s";
goto error;
}
- TRACE(("c2s is %s", c2s_cipher_algo->name))
+ TRACE(("enc c2s is %s", c2s_cipher_algo->name))
/* encryption_algorithms_server_to_client */
s2c_cipher_algo = ses.buf_match_algo(ses.payload, sshciphers, &goodguess);
@@ -630,7 +630,7 @@ static void read_kex_algos() {
erralgo = "enc s->c";
goto error;
}
- TRACE(("s2c is %s", s2c_cipher_algo->name))
+ TRACE(("enc s2c is %s", s2c_cipher_algo->name))
/* mac_algorithms_client_to_server */
c2s_hash_algo = ses.buf_match_algo(ses.payload, sshhashes, &goodguess);
@@ -638,6 +638,7 @@ static void read_kex_algos() {
erralgo = "mac c->s";
goto error;
}
+ TRACE(("hash c2s is %s", c2s_hash_algo->name))
/* mac_algorithms_server_to_client */
s2c_hash_algo = ses.buf_match_algo(ses.payload, sshhashes, &goodguess);
@@ -645,6 +646,7 @@ static void read_kex_algos() {
erralgo = "mac s->c";
goto error;
}
+ TRACE(("hash s2c is %s", s2c_hash_algo->name))
/* compression_algorithms_client_to_server */
c2s_comp_algo = ses.buf_match_algo(ses.payload, sshcompress, &goodguess);
@@ -652,6 +654,7 @@ static void read_kex_algos() {
erralgo = "comp c->s";
goto error;
}
+ TRACE(("hash c2s is %s", c2s_comp_algo->name))
/* compression_algorithms_server_to_client */
s2c_comp_algo = ses.buf_match_algo(ses.payload, sshcompress, &goodguess);
@@ -659,6 +662,7 @@ static void read_kex_algos() {
erralgo = "comp s->c";
goto error;
}
+ TRACE(("hash s2c is %s", s2c_comp_algo->name))
/* languages_client_to_server */
buf_eatstring(ses.payload);
@@ -701,13 +705,6 @@ static void read_kex_algos() {
ses.newkeys->trans_algo_comp = s2c_comp_algo->val;
}
- TRACE(("enc algo recv %s", algo->name))
- TRACE(("enc algo trans %s", algo->name))
- TRACE(("mac algo recv %s", algo->name))
- TRACE(("mac algo trans %s", algo->name))
- TRACE(("comp algo recv %s", algo->name))
- TRACE(("comp algo trans %s", algo->name))
-
/* reserved for future extensions */
buf_getint(ses.payload);
return;
diff --git a/options.h b/options.h
index 5211c778..adfcb448 100644
--- a/options.h
+++ b/options.h
@@ -62,25 +62,30 @@ etc) slower (perhaps by 50%). Recommended for most small systems. */
#define ENABLE_AGENTFWD
/* Encryption - at least one required.
- * RFC Draft requires 3DES, and recommends Blowfish, AES128 & Twofish128 */
+ * RFC Draft requires 3DES and recommends AES128 for interoperability.
+ * Including multiple keysize variants the same cipher
+ * (eg AES256 as well as AES128) will result in a minimal size increase.*/
#define DROPBEAR_AES128_CBC
+#define DROPBEAR_3DES_CBC
+#define DROPBEAR_AES256_CBC
#define DROPBEAR_BLOWFISH_CBC
+#define DROPBEAR_TWOFISH256_CBC
#define DROPBEAR_TWOFISH128_CBC
-#define DROPBEAR_3DES_CBC
-/* Integrity - at least one required.
- * RFC Draft requires sha1-hmac, and recommends md5-hmac.
+/* Message Integrity - at least one required.
+ * RFC Draft requires sha1 and recommends sha1-96.
+ * sha1-96 may be of use for slow links, as it has a smaller overhead.
*
- * Note: there's no point disabling sha1 to save space, since it's used in the
+ * Note: there's no point disabling sha1 to save space, since it's used
* for the random number generator and public-key cryptography anyway.
* Disabling it here will just stop it from being used as the integrity portion
* of the ssh protocol.
*
- * These are also used for key fingerprints in logs (when pubkey auth is used),
- * MD5 fingerprints are printed if available, however SHA1 fingerprints will be
- * generated otherwise. This isn't exactly optimal, although SHA1 fingerprints
- * are not too hard to create from pubkeys if required. */
+ * These hashes are also used for public key fingerprints in logs.
+ * If you disable MD5, Dropbear will fall back to SHA1 fingerprints,
+ * which are not the standard form. */
#define DROPBEAR_SHA1_HMAC
+#define DROPBEAR_SHA1_96_HMAC
#define DROPBEAR_MD5_HMAC
/* Hostkey/public key algorithms - at least one required, these are used
@@ -310,6 +315,14 @@ etc) slower (perhaps by 50%). Recommended for most small systems. */
#define DROPBEAR_MAX_CLI_PASS 1024
+#if defined(DROPBEAR_AES256_CBC) || defined(DROPBEAR_AES128_CBC)
+#define DROPBEAR_AES_CBC
+#endif
+
+#if defined(DROPBEAR_TWOFISH256_CBC) || defined(DROPBEAR_TWOFISH128_CBC)
+#define DROPBEAR_TWOFISH_CBC
+#endif
+
#ifndef ENABLE_X11FWD
#define DISABLE_X11FWD
#endif
diff --git a/packet.c b/packet.c
index ecda4102..ab4d70af 100644
--- a/packet.c
+++ b/packet.c
@@ -215,7 +215,7 @@ static void read_packet_init() {
if ((len > MAX_PACKET_LEN) ||
(len < MIN_PACKET_LEN + macsize) ||
((len - macsize) % blocksize != 0)) {
- dropbear_exit("bad packet size");
+ dropbear_exit("bad packet size %d", len);
}
buf_resize(ses.readbuf, len);
@@ -314,14 +314,13 @@ void decrypt_packet() {
* Returns DROPBEAR_SUCCESS or DROPBEAR_FAILURE */
static int checkmac(buffer* macbuf, buffer* sourcebuf) {
- unsigned char macsize;
+ unsigned int macsize;
hmac_state hmac;
unsigned char tempbuf[MAX_MAC_LEN];
- unsigned long hashsize;
- int len;
+ unsigned long bufsize;
+ unsigned int len;
macsize = ses.keys->recv_algo_mac->hashsize;
-
if (macsize == 0) {
return DROPBEAR_SUCCESS;
}
@@ -347,8 +346,8 @@ static int checkmac(buffer* macbuf, buffer* sourcebuf) {
dropbear_exit("HMAC error");
}
- hashsize = sizeof(tempbuf);
- if (hmac_done(&hmac, tempbuf, &hashsize) != CRYPT_OK) {
+ bufsize = sizeof(tempbuf);
+ if (hmac_done(&hmac, tempbuf, &bufsize) != CRYPT_OK) {
dropbear_exit("HMAC error");
}
@@ -524,15 +523,15 @@ void encrypt_packet() {
/* Create the packet mac, and append H(seqno|clearbuf) to the output */
static void writemac(buffer * outputbuffer, buffer * clearwritebuf) {
- int macsize;
+ unsigned int macsize;
unsigned char seqbuf[4];
- unsigned long hashsize;
+ unsigned char tempbuf[MAX_MAC_LEN];
+ unsigned long bufsize;
hmac_state hmac;
TRACE(("enter writemac"))
- macsize = ses.keys->trans_algo_mac->hashsize;
-
+ macsize = ses.keys->recv_algo_mac->hashsize;
if (macsize > 0) {
/* calculate the mac */
if (hmac_init(&hmac,
@@ -557,12 +556,12 @@ static void writemac(buffer * outputbuffer, buffer * clearwritebuf) {
dropbear_exit("HMAC error");
}
- hashsize = macsize;
- if (hmac_done(&hmac, buf_getwriteptr(outputbuffer, macsize), &hashsize)
+ bufsize = sizeof(tempbuf);
+ if (hmac_done(&hmac, tempbuf, &bufsize)
!= CRYPT_OK) {
dropbear_exit("HMAC error");
}
- buf_incrwritepos(outputbuffer, macsize);
+ buf_putbytes(outputbuffer, tempbuf, macsize);
}
TRACE(("leave writemac"))
}
--
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