void
kex_send_kexinit(Kex *kex)
{
u_int32_t rand = 0;
u_char *cookie;
int i;
if (kex == NULL) {
error("kex_send_kexinit: no kex, cannot rekey");
return;
}
if (kex->flags & KEX_INIT_SENT) {
debug("KEX_INIT_SENT");
return;
}
kex->done = 0;
/* generate a random cookie */
if (buffer_len(&kex->my) < KEX_COOKIE_LEN)
fatal("kex_send_kexinit: kex proposal too short");
cookie = buffer_ptr(&kex->my);
for (i = 0; i < KEX_COOKIE_LEN; i++) {
if (i % 4 == 0)
rand = arc4random();
cookie[i] = rand;
rand >>= 8;
}
packet_start(SSH2_MSG_KEXINIT);
packet_put_raw(buffer_ptr(&kex->my), buffer_len(&kex->my));
packet_send();
debug("SSH2_MSG_KEXINIT sent");
kex->flags |= KEX_INIT_SENT;
}
static void
roaming_auth_required(void)
{
u_char digest[SSH_DIGEST_MAX_LENGTH];
Buffer b;
u_int64_t chall, oldchall;
chall = packet_get_int64();
oldchall = packet_get_int64();
if (oldchall != lastseenchall) {
key1 = oldkey1;
key2 = oldkey2;
}
lastseenchall = chall;
buffer_init(&b);
buffer_put_int64(&b, cookie);
buffer_put_int64(&b, chall);
if (ssh_digest_buffer(SSH_DIGEST_SHA1, &b, digest, sizeof(digest)) != 0)
fatal("%s: ssh_digest_buffer failed", __func__);
buffer_free(&b);
packet_start(SSH2_MSG_KEX_ROAMING_AUTH);
packet_put_int64(key1 ^ get_recv_bytes());
packet_put_raw(digest, ssh_digest_bytes(SSH_DIGEST_SHA1));
packet_send();
oldkey1 = key1;
oldkey2 = key2;
calculate_new_key(&key1, cookie, chall);
calculate_new_key(&key2, cookie, chall);
debug("Received %llu bytes", (unsigned long long)get_recv_bytes());
debug("Sent roaming_auth packet");
}
static void
roaming_auth_required(void)
{
u_char digest[SHA_DIGEST_LENGTH];
EVP_MD_CTX md;
Buffer b;
const EVP_MD *evp_md = EVP_sha1();
u_int64_t chall, oldchall;
chall = packet_get_int64();
oldchall = packet_get_int64();
if (oldchall != lastseenchall) {
key1 = oldkey1;
key2 = oldkey2;
}
lastseenchall = chall;
buffer_init(&b);
buffer_put_int64(&b, cookie);
buffer_put_int64(&b, chall);
EVP_DigestInit(&md, evp_md);
EVP_DigestUpdate(&md, buffer_ptr(&b), buffer_len(&b));
EVP_DigestFinal(&md, digest, NULL);
buffer_free(&b);
packet_start(SSH2_MSG_KEX_ROAMING_AUTH);
packet_put_int64(key1 ^ get_recv_bytes());
packet_put_raw(digest, sizeof(digest));
packet_send();
oldkey1 = key1;
oldkey2 = key2;
calculate_new_key(&key1, cookie, chall);
calculate_new_key(&key2, cookie, chall);
#ifdef WIN32_FIXME
debug("Received %I64u bytes", (unsigned long long)get_recv_bytes());
#else
debug("Received %llu bytes", (unsigned long long)get_recv_bytes());
#endif
debug("Sent roaming_auth packet");
}
int
userauth_gssapi(Authctxt *authctxt)
{
Gssctxt *gssctxt = NULL;
static int initialized = 0;
static int mech_idx = 0;
static gss_OID_set supported = GSS_C_NULL_OID_SET;
gss_OID mech = GSS_C_NULL_OID;
/* Things work better if we send one mechanism at a time, rather
* than them all at once. This means that if we fail at some point
* in the middle of a negotiation, we can come back and try something
* different. */
if (datafellows & SSH_OLD_GSSAPI) return 0;
/* Before we offer a mechanism, check that we can support it. Don't
* bother trying to get credentials - as the standard fallback will
* deal with that kind of failure.
*/
if (!initialized) {
initialized = 1;
ssh_gssapi_client_mechs(authctxt->host, &supported);
if (supported == GSS_C_NULL_OID_SET || supported->count == 0)
return (0);
} else if (supported != GSS_C_NULL_OID_SET) {
/* Try next mech, if any */
mech_idx++;
if (mech_idx >= supported->count)
return (0);
} else {
return (0);
}
mech = &supported->elements[mech_idx];
ssh_gssapi_build_ctx(&gssctxt, 1, mech);
authctxt->methoddata=(void *)gssctxt;
packet_start(SSH2_MSG_USERAUTH_REQUEST);
packet_put_cstring(authctxt->server_user);
packet_put_cstring(authctxt->service);
packet_put_cstring(authctxt->method->name);
packet_put_int(1);
/* The newest gsskeyex draft stipulates that OIDs should
* be DER encoded, so we need to add the object type and
* length information back on */
if (datafellows & SSH_BUG_GSSAPI_BER) {
packet_put_string(mech->elements, mech->length);
} else {
packet_put_int((mech->length)+2);
packet_put_char(0x06);
packet_put_char(mech->length);
packet_put_raw(mech->elements, mech->length);
}
packet_send();
packet_write_wait();
dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE,&input_gssapi_response);
return 1;
}
static int
sign_and_send_pubkey(Authctxt *authctxt, Key *k, sign_cb_fn *sign_callback)
{
Buffer b;
u_char *blob, *signature;
u_int bloblen, slen;
int skip = 0;
int ret = -1;
int have_sig = 1;
debug3("sign_and_send_pubkey");
if (key_to_blob(k, &blob, &bloblen) == 0) {
/* we cannot handle this key */
debug3("sign_and_send_pubkey: cannot handle key");
return 0;
}
/* data to be signed */
buffer_init(&b);
if (datafellows & SSH_OLD_SESSIONID) {
buffer_append(&b, session_id2, session_id2_len);
skip = session_id2_len;
} else {
buffer_put_string(&b, session_id2, session_id2_len);
skip = buffer_len(&b);
}
buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
buffer_put_cstring(&b, authctxt->server_user);
buffer_put_cstring(&b,
datafellows & SSH_BUG_PKSERVICE ?
"ssh-userauth" :
authctxt->service);
if (datafellows & SSH_BUG_PKAUTH) {
buffer_put_char(&b, have_sig);
} else {
buffer_put_cstring(&b, authctxt->method->name);
buffer_put_char(&b, have_sig);
buffer_put_cstring(&b, key_ssh_name(k));
}
buffer_put_string(&b, blob, bloblen);
/* generate signature */
ret = (*sign_callback)(authctxt, k, &signature, &slen,
buffer_ptr(&b), buffer_len(&b));
if (ret == -1) {
xfree(blob);
buffer_free(&b);
return 0;
}
#ifdef DEBUG_PK
buffer_dump(&b);
#endif
if (datafellows & SSH_BUG_PKSERVICE) {
buffer_clear(&b);
buffer_append(&b, session_id2, session_id2_len);
skip = session_id2_len;
buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
buffer_put_cstring(&b, authctxt->server_user);
buffer_put_cstring(&b, authctxt->service);
buffer_put_cstring(&b, authctxt->method->name);
buffer_put_char(&b, have_sig);
if (!(datafellows & SSH_BUG_PKAUTH))
buffer_put_cstring(&b, key_ssh_name(k));
buffer_put_string(&b, blob, bloblen);
}
xfree(blob);
/* append signature */
buffer_put_string(&b, signature, slen);
xfree(signature);
/* skip session id and packet type */
if (buffer_len(&b) < skip + 1)
fatal("userauth_pubkey: internal error");
buffer_consume(&b, skip + 1);
/* put remaining data from buffer into packet */
packet_start(SSH2_MSG_USERAUTH_REQUEST);
packet_put_raw(buffer_ptr(&b), buffer_len(&b));
buffer_free(&b);
packet_send();
return 1;
}
/*
* Encodes terminal modes for the terminal referenced by fd
* or tiop in a portable manner, and appends the modes to a packet
* being constructed.
*/
void
tty_make_modes(int fd, struct termios *tiop)
{
struct termios tio;
int baud;
Buffer buf;
int tty_op_ospeed, tty_op_ispeed;
void (*put_arg)(Buffer *, u_int);
buffer_init(&buf);
if (compat20) {
tty_op_ospeed = TTY_OP_OSPEED_PROTO2;
tty_op_ispeed = TTY_OP_ISPEED_PROTO2;
put_arg = buffer_put_int;
} else {
tty_op_ospeed = TTY_OP_OSPEED_PROTO1;
tty_op_ispeed = TTY_OP_ISPEED_PROTO1;
put_arg = (void (*)(Buffer *, u_int)) buffer_put_char;
}
if (tiop == NULL) {
if (fd == -1) {
debug("tty_make_modes: no fd or tio");
goto end;
}
if (tcgetattr(fd, &tio) == -1) {
logit("tcgetattr: %.100s", strerror(errno));
goto end;
}
} else
tio = *tiop;
/* Store input and output baud rates. */
baud = speed_to_baud(cfgetospeed(&tio));
buffer_put_char(&buf, tty_op_ospeed);
buffer_put_int(&buf, baud);
baud = speed_to_baud(cfgetispeed(&tio));
buffer_put_char(&buf, tty_op_ispeed);
buffer_put_int(&buf, baud);
/* Store values of mode flags. */
#define TTYCHAR(NAME, OP) \
buffer_put_char(&buf, OP); \
put_arg(&buf, special_char_encode(tio.c_cc[NAME]));
#define TTYMODE(NAME, FIELD, OP) \
buffer_put_char(&buf, OP); \
put_arg(&buf, ((tio.FIELD & NAME) != 0));
#include "ttymodes.h"
#undef TTYCHAR
#undef TTYMODE
end:
/* Mark end of mode data. */
buffer_put_char(&buf, TTY_OP_END);
if (compat20)
packet_put_string(buffer_ptr(&buf), buffer_len(&buf));
else
packet_put_raw(buffer_ptr(&buf), buffer_len(&buf));
buffer_free(&buf);
}
