Commit d37dcc63 authored by Matt Johnston's avatar Matt Johnston
Browse files

Merge "none" cipher/MAC branch. Also adds sha256 and sha512

parents 804a1e69 e719a9ef
......@@ -257,7 +257,9 @@ void cli_auth_try() {
#endif
#ifdef ENABLE_CLI_INTERACT_AUTH
if (!finished && ses.authstate.authtypes & AUTH_TYPE_INTERACT) {
if (ses.keys->trans.algo_crypt->cipherdesc == NULL) {
fprintf(stderr, "Sorry, I won't let you use interactive auth unencrypted.\n");
} else if (!finished && ses.authstate.authtypes & AUTH_TYPE_INTERACT) {
if (cli_ses.auth_interact_failed) {
finished = 0;
} else {
......@@ -269,7 +271,9 @@ void cli_auth_try() {
#endif
#ifdef ENABLE_CLI_PASSWORD_AUTH
if (!finished && ses.authstate.authtypes & AUTH_TYPE_PASSWORD) {
if (ses.keys->trans.algo_crypt->cipherdesc == NULL) {
fprintf(stderr, "Sorry, I won't let you use password auth unencrypted.\n");
} else if (!finished && ses.authstate.authtypes & AUTH_TYPE_PASSWORD) {
cli_auth_password();
finished = 1;
cli_ses.lastauthtype = AUTH_TYPE_PASSWORD;
......
......@@ -133,6 +133,13 @@ static void cli_session_init() {
cli_ses.lastprivkey = NULL;
cli_ses.lastauthtype = 0;
#ifdef DROPBEAR_NONE_CIPHER
cli_ses.cipher_none_after_auth = get_algo_usable(sshciphers, "none");
set_algo_usable(sshciphers, "none", 0);
#else
cli_ses.cipher_none_after_auth = 0;
#endif
/* For printing "remote host closed" for the user */
ses.remoteclosed = cli_remoteclosed;
ses.buf_match_algo = cli_buf_match_algo;
......@@ -207,6 +214,14 @@ static void cli_sessionloop() {
case USERAUTH_SUCCESS_RCVD:
#ifdef DROPBEAR_NONE_CIPHER
if (cli_ses.cipher_none_after_auth)
{
set_algo_usable(sshciphers, "none", 1);
send_msg_kexinit();
}
#endif
if (cli_opts.backgrounded) {
int devnull;
/* keeping stdin open steals input from the terminal and
......
......@@ -106,6 +106,14 @@ static const struct dropbear_hash dropbear_sha1 =
static const struct dropbear_hash dropbear_sha1_96 =
{&sha1_desc, 20, 12};
#endif
#ifdef DROPBEAR_SHA2_256_HMAC
static const struct dropbear_hash dropbear_sha2_256 =
{&sha256_desc, 32, 32};
#endif
#ifdef DROPBEAR_SHA2_512_HMAC
static const struct dropbear_hash dropbear_sha2_512 =
{&sha512_desc, 64, 64};
#endif
#ifdef DROPBEAR_MD5_HMAC
static const struct dropbear_hash dropbear_md5 =
{&md5_desc, 16, 16};
......@@ -151,11 +159,20 @@ algo_type sshciphers[] = {
#endif
#ifdef DROPBEAR_BLOWFISH
{"blowfish-cbc", 0, &dropbear_blowfish, 1, &dropbear_mode_cbc},
#endif
#ifdef DROPBEAR_NONE_CIPHER
{"none", 0, (void*)&dropbear_nocipher, 1, &dropbear_mode_none},
#endif
{NULL, 0, NULL, 0, NULL}
};
algo_type sshhashes[] = {
#ifdef DROPBEAR_SHA2_256_HMAC
// {"hmac-sha2-256", 0, &dropbear_sha2_256, 1, NULL},
#endif
#ifdef DROPBEAR_SHA2_512_HMAC
// {"hmac-sha2-512", 0, &dropbear_sha2_512, 1, NULL},
#endif
#ifdef DROPBEAR_SHA1_96_HMAC
{"hmac-sha1-96", 0, &dropbear_sha1_96, 1, NULL},
#endif
......@@ -163,7 +180,10 @@ algo_type sshhashes[] = {
{"hmac-sha1", 0, &dropbear_sha1, 1, NULL},
#endif
#ifdef DROPBEAR_MD5_HMAC
{"hmac-md5", 0, &dropbear_md5, 1, NULL},
{"hmac-md5", 0, (void*)&dropbear_md5, 1, NULL},
#endif
#ifdef DROPBEAR_NONE_INTEGRITY
{"none", 0, (void*)&dropbear_nohash, 1, NULL},
#endif
{NULL, 0, NULL, 0, NULL}
};
......@@ -281,6 +301,38 @@ void buf_put_algolist(buffer * buf, algo_type localalgos[]) {
buf_free(algolist);
}
#ifdef DROPBEAR_NONE_CIPHER
void
set_algo_usable(algo_type algos[], const char * algo_name, int usable)
{
algo_type *a;
for (a = algos; a->name != NULL; a++)
{
if (strcmp(a->name, algo_name) == 0)
{
a->usable = usable;
return;
}
}
}
int
get_algo_usable(algo_type algos[], const char * algo_name)
{
algo_type *a;
for (a = algos; a->name != NULL; a++)
{
if (strcmp(a->name, algo_name) == 0)
{
return a->usable;
}
}
return 0;
}
#endif // DROPBEAR_NONE_CIPHER
#ifdef ENABLE_USER_ALGO_LIST
char *
......@@ -347,7 +399,8 @@ check_user_algos(const char* user_algo_list, algo_type * algos,
{
*c = '\0';
try_add_algo(last_name, algos, algo_desc, new_algos, &num_ret);
last_name = c++;
c++;
last_name = c;
}
}
try_add_algo(last_name, algos, algo_desc, new_algos, &num_ret);
......
......@@ -249,26 +249,28 @@ static void kexinitialise() {
* already initialised hash_state hs, which should already have processed
* the dh_K and hash, since these are common. X is the letter 'A', 'B' etc.
* out must have at least min(SHA1_HASH_SIZE, outlen) bytes allocated.
* The output will only be expanded once, as we are assured that
* outlen <= 2*SHA1_HASH_SIZE for all known hashes.
*
* See Section 7.2 of rfc4253 (ssh transport) for details */
static void hashkeys(unsigned char *out, int outlen,
const hash_state * hs, const unsigned char X) {
hash_state hs2;
unsigned char k2[SHA1_HASH_SIZE]; /* used to extending */
int offset;
memcpy(&hs2, hs, sizeof(hash_state));
sha1_process(&hs2, &X, 1);
sha1_process(&hs2, ses.session_id, SHA1_HASH_SIZE);
sha1_done(&hs2, out);
if (SHA1_HASH_SIZE < outlen) {
for (offset = SHA1_HASH_SIZE;
offset < outlen;
offset += SHA1_HASH_SIZE)
{
/* need to extend */
unsigned char k2[SHA1_HASH_SIZE];
memcpy(&hs2, hs, sizeof(hash_state));
sha1_process(&hs2, out, SHA1_HASH_SIZE);
sha1_process(&hs2, out, offset);
sha1_done(&hs2, k2);
memcpy(&out[SHA1_HASH_SIZE], k2, outlen - SHA1_HASH_SIZE);
memcpy(&out[offset], k2, MIN(outlen - offset, SHA1_HASH_SIZE));
}
}
......@@ -292,7 +294,6 @@ void gen_new_keys() {
hash_state hs;
unsigned int C2S_keysize, S2C_keysize;
char mactransletter, macrecvletter; /* Client or server specific */
int recv_cipher = 0, trans_cipher = 0;
TRACE(("enter gen_new_keys"))
/* the dh_K and hash are the start of all hashes, we make use of that */
......@@ -329,31 +330,39 @@ void gen_new_keys() {
hashkeys(C2S_key, C2S_keysize, &hs, 'C');
hashkeys(S2C_key, S2C_keysize, &hs, 'D');
recv_cipher = find_cipher(ses.newkeys->recv.algo_crypt->cipherdesc->name);
if (recv_cipher < 0)
dropbear_exit("Crypto error");
if (ses.newkeys->recv.crypt_mode->start(recv_cipher,
recv_IV, recv_key,
ses.newkeys->recv.algo_crypt->keysize, 0,
&ses.newkeys->recv.cipher_state) != CRYPT_OK) {
dropbear_exit("Crypto error");
}
trans_cipher = find_cipher(ses.newkeys->trans.algo_crypt->cipherdesc->name);
if (trans_cipher < 0)
dropbear_exit("Crypto error");
if (ses.newkeys->trans.crypt_mode->start(trans_cipher,
trans_IV, trans_key,
ses.newkeys->trans.algo_crypt->keysize, 0,
&ses.newkeys->trans.cipher_state) != CRYPT_OK) {
dropbear_exit("Crypto error");
if (ses.newkeys->recv.algo_crypt->cipherdesc != NULL) {
int recv_cipher = find_cipher(ses.newkeys->recv.algo_crypt->cipherdesc->name);
if (recv_cipher < 0)
dropbear_exit("Crypto error");
if (ses.newkeys->recv.crypt_mode->start(recv_cipher,
recv_IV, recv_key,
ses.newkeys->recv.algo_crypt->keysize, 0,
&ses.newkeys->recv.cipher_state) != CRYPT_OK) {
dropbear_exit("Crypto error");
}
}
if (ses.newkeys->trans.algo_crypt->cipherdesc != NULL) {
int trans_cipher = find_cipher(ses.newkeys->trans.algo_crypt->cipherdesc->name);
if (trans_cipher < 0)
dropbear_exit("Crypto error");
if (ses.newkeys->trans.crypt_mode->start(trans_cipher,
trans_IV, trans_key,
ses.newkeys->trans.algo_crypt->keysize, 0,
&ses.newkeys->trans.cipher_state) != CRYPT_OK) {
dropbear_exit("Crypto error");
}
}
/* MAC keys */
hashkeys(ses.newkeys->trans.mackey,
ses.newkeys->trans.algo_mac->keysize, &hs, mactransletter);
hashkeys(ses.newkeys->recv.mackey,
ses.newkeys->recv.algo_mac->keysize, &hs, macrecvletter);
if (ses.newkeys->trans.algo_mac->hashdesc != NULL) {
hashkeys(ses.newkeys->trans.mackey,
ses.newkeys->trans.algo_mac->keysize, &hs, mactransletter);
}
if (ses.newkeys->recv.algo_mac->hashdesc != NULL) {
hashkeys(ses.newkeys->recv.mackey,
ses.newkeys->recv.algo_mac->keysize, &hs, macrecvletter);
}
ses.newkeys->trans.hash_index = find_hash(ses.newkeys->trans.algo_mac->hashdesc->name),
ses.newkeys->recv.hash_index = find_hash(ses.newkeys->recv.algo_mac->hashdesc->name),
......
......@@ -118,16 +118,20 @@
#define LTC_CTR_MODE
#endif
#if defined(DROPBEAR_DSS) && defined(DSS_PROTOK)
#define SHA512
#endif
#define SHA1
#ifdef DROPBEAR_MD5_HMAC
#ifdef DROPBEAR_MD5
#define MD5
#endif
#ifdef DROPBEAR_SHA256
#define SHA256
#endif
#ifdef DROPBEAR_SHA512
#define SHA512
#endif
#define LTC_HMAC
/* Various tidbits of modern neatoness */
......
......@@ -100,6 +100,12 @@ much traffic. */
* size and is recommended for most cases */
#define DROPBEAR_ENABLE_CTR_MODE
/* You can compile with no encryption if you want. In some circumstances
* this could be safe security-wise, though make sure you know what
* you're doing. Anyone can see everything that goes over the wire, so
* the only safe auth method is public key. */
#define DROPBEAR_NONE_CIPHER
/* Message Integrity - at least one required.
* Protocol RFC requires sha1 and recommends sha1-96.
* sha1-96 is of use for slow links as it has a smaller overhead.
......@@ -112,11 +118,19 @@ much traffic. */
* 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_SHA2_256_HMAC*/
/*#define DROPBEAR_SHA2_512_HMAC*/
#define DROPBEAR_MD5_HMAC
/* You can also disable integrity. Don't bother disabling this if you're
* still using a cipher, it's relatively cheap. If you disable this it's dead
* simple to run arbitrary commands on the remote host. Beware.
* Note again, for the client you will have to disable other hashes above
* to use this. */
#define DROPBEAR_NONE_INTEGRITY
/* Hostkey/public key algorithms - at least one required, these are used
* for hostkey as well as for verifying signatures with pubkey auth.
* Removing either of these won't save very much space.
......
......@@ -269,6 +269,9 @@ struct clientsession {
int interact_request_received; /* flag whether we've received an
info request from the server for
interactive auth.*/
int cipher_none_after_auth; /* Set to 1 if the user requested "none"
auth */
#endif
sign_key *lastprivkey;
......
......@@ -90,7 +90,13 @@
#define MAX_KEY_LEN 32 /* 256 bits for aes256 etc */
#define MAX_IV_LEN 20 /* must be same as max blocksize,
and >= SHA1_HASH_SIZE */
#if defined(DROPBEAR_SHA2_512_HMAC)
#define MAX_MAC_KEY 64
#elif defined(DROPBEAR_SHA2_256_HMAC)
#define MAX_MAC_KEY 32
#else
#define MAX_MAC_KEY 20
#endif
#define MAX_NAME_LEN 64 /* maximum length of a protocol name, isn't
explicitly specified for all protocols (just
......@@ -144,6 +150,19 @@
#define DROPBEAR_TWOFISH
#endif
#ifdef DROPBEAR_MD5_HMAC
#define DROPBEAR_MD5
#endif
#ifdef DROPBEAR_SHA2_256_HMAC
#define DROPBEAR_SHA256
#endif
#if (defined(DROPBEAR_DSS) && defined(DSS_PROTOK)) \
|| defined(DROPBEAR_SHA2_512_HMAC)
#define DROPBEAR_SHA512
#endif
#ifndef ENABLE_X11FWD
#define DISABLE_X11FWD
#endif
......
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