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- markus@cvs.openbsd.org 2001/04/04 20:25:38 

[channels.c channels.h clientloop.c kex.c kex.h serverloop.c
      sshconnect2.c sshd.c]
     more robust rekeying
     don't send channel data after rekeying is started.
This commit is contained in:
Ben Lindstrom 2001-04-04 23:46:07 +00:00
parent 78c261ab4a
commit be2cc43c3a
9 changed files with 96 additions and 63 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
ChangeLog
View File

@ -12,6 +12,11 @@
- markus@cvs.openbsd.org 2001/04/04 15:50:55
[compat.c]
f-secure 1.3.2 does not handle IGNORE; from milliondl@ornl.gov
- markus@cvs.openbsd.org 2001/04/04 20:25:38
[channels.c channels.h clientloop.c kex.c kex.h serverloop.c
sshconnect2.c sshd.c]
more robust rekeying
don't send channel data after rekeying is started.
20010404
- OpenBSD CVS Sync
@ -4851,4 +4856,4 @@
- Wrote replacements for strlcpy and mkdtemp
- Released 1.0pre1
$Id: ChangeLog,v 1.1057 2001/04/04 23:43:26 mouring Exp $
$Id: ChangeLog,v 1.1058 2001/04/04 23:46:07 mouring Exp $

8
channels.c
View File

@ -40,7 +40,7 @@
*/
#include "includes.h"
RCSID("$OpenBSD: channels.c,v 1.99 2001/03/16 19:06:29 markus Exp $");
RCSID("$OpenBSD: channels.c,v 1.100 2001/04/04 20:25:35 markus Exp $");
#include <openssl/rsa.h>
#include <openssl/dsa.h>
@ -1005,7 +1005,8 @@ channel_handler(chan_fn *ftab[], fd_set * readset, fd_set * writeset)
}
void
channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp)
channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
int rekeying)
{
int n;
u_int sz;
@ -1025,7 +1026,8 @@ channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp)
memset(*readsetp, 0, sz);
memset(*writesetp, 0, sz);
channel_handler(channel_pre, *readsetp, *writesetp);
if (!rekeying)
channel_handler(channel_pre, *readsetp, *writesetp);
}
void

5
channels.h
View File

@ -32,7 +32,7 @@
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* RCSID("$OpenBSD: channels.h,v 1.28 2001/03/16 19:06:29 markus Exp $"); */
/* RCSID("$OpenBSD: channels.h,v 1.29 2001/04/04 20:25:36 markus Exp $"); */
#ifndef CHANNELS_H
#define CHANNELS_H
@ -171,7 +171,8 @@ void channel_free(int channel);
* select bitmasks.
*/
void
channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp);
channel_prepare_select(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
int rekeying);
/*
* After select, perform any appropriate operations for channels which have

75
clientloop.c
View File

@ -59,7 +59,7 @@
*/
#include "includes.h"
RCSID("$OpenBSD: clientloop.c,v 1.55 2001/04/04 14:34:58 markus Exp $");
RCSID("$OpenBSD: clientloop.c,v 1.56 2001/04/04 20:25:37 markus Exp $");
#include "ssh.h"
#include "ssh1.h"
@ -127,6 +127,7 @@ static u_long stdin_bytes, stdout_bytes, stderr_bytes;
static u_int buffer_high;/* Soft max buffer size. */
static int connection_in; /* Connection to server (input). */
static int connection_out; /* Connection to server (output). */
static int need_rekeying; /* Set to non-zero if rekeying is requested. */
void client_init_dispatch(void);
int session_ident = -1;
@ -367,10 +368,10 @@ client_check_window_change(void)
void
client_wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp,
int *maxfdp)
int *maxfdp, int rekeying)
{
/* Add any selections by the channel mechanism. */
channel_prepare_select(readsetp, writesetp, maxfdp);
channel_prepare_select(readsetp, writesetp, maxfdp, rekeying);
if (!compat20) {
/* Read from the connection, unless our buffers are full. */
@ -553,8 +554,8 @@ process_escapes(Buffer *bin, Buffer *bout, Buffer *berr, char *buf, int len)
continue;
case 'R':
debug("Rekeying");
kex_send_kexinit(xxx_kex);
if (compat20)
need_rekeying = 1;
continue;
case '&':
@ -794,9 +795,8 @@ int
client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
{
fd_set *readset = NULL, *writeset = NULL;
int max_fd = 0;
double start_time, total_time;
int len;
int max_fd = 0, len, rekeying = 0;
char buf[100];
debug("Entering interactive session.");
@ -858,45 +858,60 @@ client_loop(int have_pty, int escape_char_arg, int ssh2_chan_id)
/* Process buffered packets sent by the server. */
client_process_buffered_input_packets();
rekeying = (xxx_kex != NULL && !xxx_kex->done);
if (compat20 && !channel_still_open()) {
debug2("!channel_still_open.");
break;
}
/*
* Make packets of buffered stdin data, and buffer them for
* sending to the server.
*/
if (!compat20)
client_make_packets_from_stdin_data();
if (rekeying) {
debug("rekeying in progress");
} else {
/*
* Make packets of buffered stdin data, and buffer
* them for sending to the server.
*/
if (!compat20)
client_make_packets_from_stdin_data();
/*
* Make packets from buffered channel data, and enqueue them
* for sending to the server.
*/
if (packet_not_very_much_data_to_write())
channel_output_poll();
/*
* Make packets from buffered channel data, and
* enqueue them for sending to the server.
*/
if (packet_not_very_much_data_to_write())
channel_output_poll();
/*
* Check if the window size has changed, and buffer a message
* about it to the server if so.
*/
client_check_window_change();
if (quit_pending)
break;
/*
* Check if the window size has changed, and buffer a
* message about it to the server if so.
*/
client_check_window_change();
if (quit_pending)
break;
}
/*
* Wait until we have something to do (something becomes
* available on one of the descriptors).
*/
client_wait_until_can_do_something(&readset, &writeset, &max_fd);
client_wait_until_can_do_something(&readset, &writeset,
&max_fd, rekeying);
if (quit_pending)
break;
/* Do channel operations. */
channel_after_select(readset, writeset);
/* Do channel operations unless rekeying in progress. */
if (!rekeying) {
channel_after_select(readset, writeset);
if (need_rekeying) {
debug("user requests rekeying");
xxx_kex->done = 0;
kex_send_kexinit(xxx_kex);
need_rekeying = 0;
}
}
/* Buffer input from the connection. */
client_process_net_input(readset);

46
kex.c
View File

@ -23,7 +23,7 @@
*/
#include "includes.h"
RCSID("$OpenBSD: kex.c,v 1.29 2001/04/04 14:34:58 markus Exp $");
RCSID("$OpenBSD: kex.c,v 1.30 2001/04/04 20:25:37 markus Exp $");
#include <openssl/crypto.h>
@ -136,7 +136,7 @@ kex_finish(Kex *kex)
debug("waiting for SSH2_MSG_NEWKEYS");
packet_read_expect(&plen, SSH2_MSG_NEWKEYS);
debug("SSH2_MSG_NEWKEYS received");
kex->newkeys = 1;
kex->done = 1;
buffer_clear(&kex->peer);
/* buffer_clear(&kex->my); */
kex->flags &= ~KEX_INIT_SENT;
@ -153,6 +153,7 @@ kex_send_kexinit(Kex *kex)
debug("KEX_INIT_SENT");
return;
}
kex->done = 0;
packet_start(SSH2_MSG_KEXINIT);
packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my));
packet_send();
@ -187,7 +188,7 @@ kex_setup(char *proposal[PROPOSAL_MAX])
buffer_init(&kex->peer);
buffer_init(&kex->my);
kex_prop2buf(&kex->my, proposal);
kex->newkeys = 0;
kex->done = 0;
kex_send_kexinit(kex); /* we start */
kex_clear_dispatch();
@ -307,10 +308,11 @@ kex_choose_conf(Kex *kex)
sprop=peer;
}
/* Algorithm Negotiation */
for (mode = 0; mode < MODE_MAX; mode++) {
newkeys = xmalloc(sizeof(*newkeys));
memset(newkeys, 0, sizeof(*newkeys));
kex->keys[mode] = newkeys;
kex->newkeys[mode] = newkeys;
ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN);
nenc = ctos ? PROPOSAL_ENC_ALGS_CTOS : PROPOSAL_ENC_ALGS_STOC;
nmac = ctos ? PROPOSAL_MAC_ALGS_CTOS : PROPOSAL_MAC_ALGS_STOC;
@ -329,7 +331,7 @@ kex_choose_conf(Kex *kex)
sprop[PROPOSAL_SERVER_HOST_KEY_ALGS]);
need = 0;
for (mode = 0; mode < MODE_MAX; mode++) {
newkeys = kex->keys[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)
@ -353,19 +355,24 @@ derive_key(Kex *kex, int id, int need, u_char *hash, BIGNUM *shared_secret)
char c = id;
int have;
int mdsz = evp_md->md_size;
u_char *digest = xmalloc(((need+mdsz-1)/mdsz)*mdsz);
u_char *digest = xmalloc(roundup(need, mdsz));
buffer_init(&b);
buffer_put_bignum2(&b, shared_secret);
/* K1 = HASH(K || H || "A" || session_id) */
EVP_DigestInit(&md, evp_md);
EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b)); /* shared_secret K */
EVP_DigestUpdate(&md, hash, mdsz); /* transport-06 */
EVP_DigestUpdate(&md, &c, 1); /* key id */
EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
EVP_DigestUpdate(&md, hash, mdsz);
EVP_DigestUpdate(&md, &c, 1);
EVP_DigestUpdate(&md, kex->session_id, kex->session_id_len);
EVP_DigestFinal(&md, digest, NULL);
/* expand */
/*
* expand key:
* Kn = HASH(K || H || K1 || K2 || ... || Kn-1)
* Key = K1 || K2 || ... || Kn
*/
for (have = mdsz; need > have; have += mdsz) {
EVP_DigestInit(&md, evp_md);
EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
@ -381,13 +388,12 @@ derive_key(Kex *kex, int id, int need, u_char *hash, BIGNUM *shared_secret)
return digest;
}
Newkeys *x_newkeys[MODE_MAX];
Newkeys *current_keys[MODE_MAX];
#define NKEYS 6
void
kex_derive_keys(Kex *kex, u_char *hash, BIGNUM *shared_secret)
{
Newkeys *newkeys;
u_char *keys[NKEYS];
int i, mode, ctos;
@ -396,19 +402,23 @@ kex_derive_keys(Kex *kex, u_char *hash, BIGNUM *shared_secret)
debug("kex_derive_keys");
for (mode = 0; mode < MODE_MAX; mode++) {
newkeys = kex->keys[mode];
current_keys[mode] = kex->newkeys[mode];
kex->newkeys[mode] = NULL;
ctos = (!kex->server && mode == MODE_OUT) || (kex->server && mode == MODE_IN);
newkeys->enc.iv = keys[ctos ? 0 : 1];
newkeys->enc.key = keys[ctos ? 2 : 3];
newkeys->mac.key = keys[ctos ? 4 : 5];
x_newkeys[mode] = newkeys;
current_keys[mode]->enc.iv = keys[ctos ? 0 : 1];
current_keys[mode]->enc.key = keys[ctos ? 2 : 3];
current_keys[mode]->mac.key = keys[ctos ? 4 : 5];
}
}
Newkeys *
kex_get_newkeys(int mode)
{
return x_newkeys[mode];
Newkeys *ret;
ret = current_keys[mode];
current_keys[mode] = NULL;
return ret;
}
#if defined(DEBUG_KEX) || defined(DEBUG_KEXDH)

6
kex.h
View File

@ -1,4 +1,4 @@
/* $OpenBSD: kex.h,v 1.21 2001/04/04 14:34:58 markus Exp $ */
/* $OpenBSD: kex.h,v 1.22 2001/04/04 20:25:37 markus Exp $ */
/*
* Copyright (c) 2000 Markus Friedl. All rights reserved.
@ -95,7 +95,7 @@ struct Newkeys {
struct Kex {
u_char *session_id;
int session_id_len;
Newkeys *keys[MODE_MAX];
Newkeys *newkeys[MODE_MAX];
int we_need;
int server;
char *name;
@ -103,7 +103,7 @@ struct Kex {
int kex_type;
Buffer my;
Buffer peer;
int newkeys;
int done;
int flags;
char *client_version_string;
char *server_version_string;

4
serverloop.c
View File

@ -35,7 +35,7 @@
*/
#include "includes.h"
RCSID("$OpenBSD: serverloop.c,v 1.56 2001/04/04 14:34:58 markus Exp $");
RCSID("$OpenBSD: serverloop.c,v 1.57 2001/04/04 20:25:37 markus Exp $");
#include "xmalloc.h"
#include "packet.h"
@ -194,7 +194,7 @@ wait_until_can_do_something(fd_set **readsetp, fd_set **writesetp, int *maxfdp,
retry_select:
/* Allocate and update select() masks for channel descriptors. */
channel_prepare_select(readsetp, writesetp, maxfdp);
channel_prepare_select(readsetp, writesetp, maxfdp, 0);
if (compat20) {
/* wrong: bad condition XXX */

4
sshconnect2.c
View File

@ -23,7 +23,7 @@
*/
#include "includes.h"
RCSID("$OpenBSD: sshconnect2.c,v 1.65 2001/04/04 14:34:58 markus Exp $");
RCSID("$OpenBSD: sshconnect2.c,v 1.66 2001/04/04 20:25:38 markus Exp $");
#include <openssl/bn.h>
#include <openssl/md5.h>
@ -119,7 +119,7 @@ ssh_kex2(char *host, struct sockaddr *hostaddr)
xxx_kex = kex;
dispatch_run(DISPATCH_BLOCK, &kex->newkeys, kex);
dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
session_id2 = kex->session_id;
session_id2_len = kex->session_id_len;

4
sshd.c
View File

@ -40,7 +40,7 @@
*/
#include "includes.h"
RCSID("$OpenBSD: sshd.c,v 1.189 2001/04/04 14:34:58 markus Exp $");
RCSID("$OpenBSD: sshd.c,v 1.190 2001/04/04 20:25:38 markus Exp $");
#include <openssl/dh.h>
#include <openssl/bn.h>
@ -1437,7 +1437,7 @@ do_ssh2_kex(void)
xxx_kex = kex;
dispatch_run(DISPATCH_BLOCK, &kex->newkeys, kex);
dispatch_run(DISPATCH_BLOCK, &kex->done, kex);
session_id2 = kex->session_id;
session_id2_len = kex->session_id_len;