#define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
#define BUG_CHOKES_ON_RSA 8
#define BUG_SSH2_RSA_PADDING 16
+#define BUG_SSH2_DERIVEKEY 32
static int ssh_pkt_ctx = 0;
static const struct ssh_kex *kex = NULL;
static const struct ssh_signkey *hostkey = NULL;
static unsigned char ssh2_session_id[20];
-int (*ssh_get_line) (const char *prompt, char *str, int maxlen,
- int is_pw) = NULL;
static char *savedhost;
static int savedport;
st->pad = pktin.data[4];
/*
+ * _Completely_ silly lengths should be stomped on before they
+ * do us any more damage.
+ */
+ if (st->len < 0 || st->pad < 0 || st->len + st->pad < 0) {
+ bombout(("Incoming packet was garbled on decryption"));
+ crReturn(0);
+ }
+
+ /*
* This enables us to deduce the payload length.
*/
st->payload = st->len - st->pad - 1;
static void ssh2_pkt_getstring(char **p, int *length)
{
*p = NULL;
+ *length = 0;
if (pktin.length - pktin.savedpos < 4)
return;
*length = GET_32BIT(pktin.data + pktin.savedpos);
logevent("We believe remote version has SSH2 HMAC bug");
}
+ if (!strncmp(imp, "2.0.", 4)) {
+ /*
+ * These versions have the key-derivation bug (failing to
+ * include the literal shared secret in the hashes that
+ * generate the keys).
+ */
+ ssh_remote_bugs |= BUG_SSH2_DERIVEKEY;
+ logevent("We believe remote version has SSH2 key-derivation bug");
+ }
+
if ((!strncmp(imp, "OpenSSH_2.", 10) && imp[10]>='5' && imp[10]<='9') ||
(!strncmp(imp, "OpenSSH_3.", 10) && imp[10]>='0' && imp[10]<='2')) {
/*
static int vstrsize;
static char *vlog;
static int i;
+ static int proto1, proto2;
crBegin;
sfree(vlog);
/*
- * Server version "1.99" means we can choose whether we use v1
- * or v2 protocol. Choice is based on cfg.sshprot.
+ * Decide which SSH protocol version to support.
*/
- if (ssh_versioncmp(version, cfg.sshprot == 1 ? "2.0" : "1.99") >= 0) {
+
+ /* Anything strictly below "2.0" means protocol 1 is supported. */
+ proto1 = ssh_versioncmp(version, "2.0") < 0;
+ /* Anything greater or equal to "1.99" means protocol 2 is supported. */
+ proto2 = ssh_versioncmp(version, "1.99") >= 0;
+
+ if (cfg.sshprot == 0 && !proto1) {
+ bombout(("SSH protocol version 1 required by user but not provided by server"));
+ crReturn(0);
+ }
+ if (cfg.sshprot == 3 && !proto2) {
+ bombout(("SSH protocol version 2 required by user but not provided by server"));
+ crReturn(0);
+ }
+
+ if (proto2 && (cfg.sshprot >= 2 || !proto1)) {
/*
- * This is a v2 server. Begin v2 protocol.
+ * Use v2 protocol.
*/
char verstring[80], vlog[100];
sprintf(verstring, "SSH-2.0-%s", sshver);
s_rdpkt = ssh2_rdpkt;
} else {
/*
- * This is a v1 server. Begin v1 protocol.
+ * Use v1 protocol.
*/
char verstring[80], vlog[100];
sprintf(verstring, "SSH-%s-%s",
sprintf(vlog, "We claim version: %s", verstring);
logevent(vlog);
strcat(verstring, "\n");
-
- if (cfg.sshprot == 3) {
- bombout(("SSH protocol version 2 required by user but not provided by server"));
- crReturn(0);
- }
logevent("Using SSH protocol version 1");
sk_write(s, verstring, strlen(verstring));
}
/*
+ * Username and password input, abstracted off into reusable
+ * routines (hopefully even reusable between SSH1 and SSH2!).
+ */
+static char *ssh_userpass_input_buffer;
+static int ssh_userpass_input_buflen;
+static int ssh_userpass_input_bufpos;
+static int ssh_userpass_input_echo;
+
+/* Set up a username or password input loop on a given buffer. */
+void setup_userpass_input(char *buffer, int buflen, int echo)
+{
+ ssh_userpass_input_buffer = buffer;
+ ssh_userpass_input_buflen = buflen;
+ ssh_userpass_input_bufpos = 0;
+ ssh_userpass_input_echo = echo;
+}
+
+/*
+ * Process some terminal data in the course of username/password
+ * input. Returns >0 for success (line of input returned in
+ * buffer), <0 for failure (user hit ^C/^D, bomb out and exit), 0
+ * for inconclusive (keep waiting for more input please).
+ */
+int process_userpass_input(unsigned char *in, int inlen)
+{
+ char c;
+
+ while (inlen--) {
+ switch (c = *in++) {
+ case 10:
+ case 13:
+ ssh_userpass_input_buffer[ssh_userpass_input_bufpos] = 0;
+ ssh_userpass_input_buffer[ssh_userpass_input_buflen-1] = 0;
+ return +1;
+ break;
+ case 8:
+ case 127:
+ if (ssh_userpass_input_bufpos > 0) {
+ if (ssh_userpass_input_echo)
+ c_write_str("\b \b");
+ ssh_userpass_input_bufpos--;
+ }
+ break;
+ case 21:
+ case 27:
+ while (ssh_userpass_input_bufpos > 0) {
+ if (ssh_userpass_input_echo)
+ c_write_str("\b \b");
+ ssh_userpass_input_bufpos--;
+ }
+ break;
+ case 3:
+ case 4:
+ return -1;
+ break;
+ default:
+ if (((c >= ' ' && c <= '~') ||
+ ((unsigned char) c >= 160))
+ && ssh_userpass_input_bufpos < ssh_userpass_input_buflen-1) {
+ ssh_userpass_input_buffer[ssh_userpass_input_bufpos++] = c;
+ if (ssh_userpass_input_echo)
+ c_write(&c, 1);
+ }
+ break;
+ }
+ }
+ return 0;
+}
+
+/*
* Handle the key exchange and user authentication phases.
*/
static int do_ssh1_login(unsigned char *in, int inlen, int ispkt)
fflush(stdout);
{
- static int pos = 0;
- static char c;
if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
- if (ssh_get_line) {
+ if (ssh_get_line && !ssh_getline_pw_only) {
if (!ssh_get_line("login as: ",
username, sizeof(username), FALSE)) {
/*
crReturn(1);
}
} else {
+ static int ret;
c_write_str("login as: ");
ssh_send_ok = 1;
- while (pos >= 0) {
+
+ setup_userpass_input(username, sizeof(username), 1);
+ do {
crWaitUntil(!ispkt);
- while (inlen--)
- switch (c = *in++) {
- case 10:
- case 13:
- username[pos] = 0;
- pos = -1;
- break;
- case 8:
- case 127:
- if (pos > 0) {
- c_write_str("\b \b");
- pos--;
- }
- break;
- case 21:
- case 27:
- while (pos > 0) {
- c_write_str("\b \b");
- pos--;
- }
- break;
- case 3:
- case 4:
- cleanup_exit(0);
- break;
- default:
- if (((c >= ' ' && c <= '~') ||
- ((unsigned char) c >= 160))
- && pos < sizeof(username)-1) {
- username[pos++] = c;
- c_write(&c, 1);
- }
- break;
- }
- }
+ ret = process_userpass_input(in, inlen);
+ } while (ret == 0);
+ if (ret < 0)
+ cleanup_exit(0);
c_write_str("\r\n");
- username[strcspn(username, "\n\r")] = '\0';
}
} else {
strncpy(username, cfg.username, 99);
} else {
/* Prompt may have come from server. We've munged it a bit, so
* we know it to be zero-terminated at least once. */
+ static int ret;
c_write_untrusted(prompt, strlen(prompt));
pos = 0;
- ssh_send_ok = 1;
- while (pos >= 0) {
+
+ setup_userpass_input(password, sizeof(password), 0);
+ do {
crWaitUntil(!ispkt);
- while (inlen--)
- switch (c = *in++) {
- case 10:
- case 13:
- password[pos] = 0;
- pos = -1;
- break;
- case 8:
- case 127:
- if (pos > 0)
- pos--;
- break;
- case 21:
- case 27:
- pos = 0;
- break;
- case 3:
- case 4:
- cleanup_exit(0);
- break;
- default:
- if (pos < sizeof(password)-1)
- password[pos++] = c;
- break;
- }
- }
+ ret = process_userpass_input(in, inlen);
+ } while (ret == 0);
+ if (ret < 0)
+ cleanup_exit(0);
c_write_str("\r\n");
}
SHA_State s;
/* First 20 bytes. */
SHA_Init(&s);
- sha_mpint(&s, K);
+ if (!(ssh_remote_bugs & BUG_SSH2_DERIVEKEY))
+ sha_mpint(&s, K);
SHA_Bytes(&s, H, 20);
SHA_Bytes(&s, &chr, 1);
SHA_Bytes(&s, sessid, 20);
SHA_Final(&s, keyspace);
/* Next 20 bytes. */
SHA_Init(&s);
- sha_mpint(&s, K);
+ if (!(ssh_remote_bugs & BUG_SSH2_DERIVEKEY))
+ sha_mpint(&s, K);
SHA_Bytes(&s, H, 20);
SHA_Bytes(&s, keyspace, 20);
SHA_Final(&s, keyspace + 20);
static int tried_pubkey_config, tried_agent, tried_keyb_inter;
static int kbd_inter_running;
static int we_are_in;
- static int num_prompts, echo;
+ static int num_prompts, curr_prompt, echo;
static char username[100];
static int got_username;
static char pwprompt[200];
username[0] = '\0';
got_username = FALSE;
do {
- static int pos;
- static char c;
-
/*
* Get a username.
*/
- pos = 0;
if (got_username && !cfg.change_username) {
/*
* We got a username last time round this loop, and
* it again.
*/
} else if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
- if (ssh_get_line) {
+ if (ssh_get_line && !ssh_getline_pw_only) {
if (!ssh_get_line("login as: ",
username, sizeof(username), FALSE)) {
/*
crReturnV;
}
} else {
+ static int ret;
c_write_str("login as: ");
ssh_send_ok = 1;
- while (pos >= 0) {
+ setup_userpass_input(username, sizeof(username), 1);
+ do {
crWaitUntilV(!ispkt);
- while (inlen--)
- switch (c = *in++) {
- case 10:
- case 13:
- username[pos] = 0;
- pos = -1;
- break;
- case 8:
- case 127:
- if (pos > 0) {
- c_write_str("\b \b");
- pos--;
- }
- break;
- case 21:
- case 27:
- while (pos > 0) {
- c_write_str("\b \b");
- pos--;
- }
- break;
- case 3:
- case 4:
- cleanup_exit(0);
- break;
- default:
- if (((c >= ' ' && c <= '~') ||
- ((unsigned char) c >= 160))
- && pos < sizeof(username)-1) {
- username[pos++] = c;
- c_write(&c, 1);
- }
- break;
- }
- }
+ ret = process_userpass_input(in, inlen);
+ } while (ret == 0);
+ if (ret < 0)
+ cleanup_exit(0);
}
c_write_str("\r\n");
username[strcspn(username, "\n\r")] = '\0';
if (kbd_inter_running &&
pktin.type == SSH2_MSG_USERAUTH_INFO_REQUEST) {
/*
- * This is a further prompt in keyboard-interactive
- * authentication. Do nothing.
+ * This is either a further set-of-prompts packet
+ * in keyboard-interactive authentication, or it's
+ * the same one and we came back here with `gotit'
+ * set. In the former case, we must reset the
+ * curr_prompt variable.
*/
+ if (!gotit)
+ curr_prompt = 0;
} else if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
bombout(("Strange packet received during authentication: type %d",
pktin.type));
method = 0;
ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
+ /*
+ * Most password/passphrase prompts will be
+ * non-echoing, so we set this to 0 by default.
+ * Exception is that some keyboard-interactive prompts
+ * can be echoing, in which case we'll set this to 1.
+ */
+ echo = 0;
+
if (!method && can_pubkey && agent_exists() && !tried_agent) {
/*
* Attempt public-key authentication using Pageant.
static int authed = FALSE;
void *r;
+ ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
ssh_pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
tried_agent = TRUE;
tried_pubkey_config = TRUE;
+ ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
ssh_pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
/*
type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
tried_keyb_inter = TRUE;
+ ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
ssh_pkt_ctx |= SSH2_PKTCTX_KBDINTER;
ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
}
kbd_inter_running = TRUE;
+ curr_prompt = 0;
}
if (kbd_inter_running) {
type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
tried_keyb_inter = TRUE;
+ ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
ssh_pkt_ctx |= SSH2_PKTCTX_KBDINTER;
- /* We've got packet with that "interactive" info
- dump banners, and set its prompt as ours */
- {
- char *name, *inst, *lang, *prompt;
- int name_len, inst_len, lang_len, prompt_len;
+ if (curr_prompt == 0) {
+ /*
+ * We've got a fresh USERAUTH_INFO_REQUEST.
+ * Display header data, and start going through
+ * the prompts.
+ */
+ char *name, *inst, *lang;
+ int name_len, inst_len, lang_len;
+
ssh2_pkt_getstring(&name, &name_len);
ssh2_pkt_getstring(&inst, &inst_len);
ssh2_pkt_getstring(&lang, &lang_len);
- if (name_len > 0)
+ if (name_len > 0) {
c_write_untrusted(name, name_len);
- if (inst_len > 0)
+ c_write_str("\r\n");
+ }
+ if (inst_len > 0) {
c_write_untrusted(inst, inst_len);
+ c_write_str("\r\n");
+ }
num_prompts = ssh2_pkt_getuint32();
+ }
- ssh2_pkt_getstring(&prompt, &prompt_len);
- strncpy(pwprompt, prompt, sizeof(pwprompt));
- pwprompt[prompt_len < sizeof(pwprompt) ?
- prompt_len : sizeof(pwprompt)-1] = '\0';
- need_pw = TRUE;
+ /*
+ * If there are prompts remaining in the packet,
+ * display one and get a response.
+ */
+ if (curr_prompt < num_prompts) {
+ char *prompt;
+ int prompt_len;
+ ssh2_pkt_getstring(&prompt, &prompt_len);
+ if (prompt_len > 0) {
+ strncpy(pwprompt, prompt, sizeof(pwprompt));
+ pwprompt[prompt_len < sizeof(pwprompt) ?
+ prompt_len : sizeof(pwprompt)-1] = '\0';
+ } else {
+ strcpy(pwprompt,
+ "<server failed to send prompt>: ");
+ }
echo = ssh2_pkt_getbool();
- }
+ need_pw = TRUE;
+ } else
+ need_pw = FALSE;
}
if (!method && can_passwd) {
method = AUTH_PASSWORD;
+ ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
ssh_pkt_ctx |= SSH2_PKTCTX_PASSWORD;
sprintf(pwprompt, "%.90s@%.90s's password: ", username,
savedhost);
crReturnV;
}
} else {
- static int pos = 0;
- static char c;
-
+ static int ret;
c_write_untrusted(pwprompt, strlen(pwprompt));
ssh_send_ok = 1;
- pos = 0;
- while (pos >= 0) {
+ setup_userpass_input(password, sizeof(password), echo);
+ do {
crWaitUntilV(!ispkt);
- while (inlen--)
- switch (c = *in++) {
- case 10:
- case 13:
- password[pos] = 0;
- pos = -1;
- break;
- case 8:
- case 127:
- if (pos > 0)
- pos--;
- break;
- case 21:
- case 27:
- pos = 0;
- break;
- case 3:
- case 4:
- cleanup_exit(0);
- break;
- default:
- if (pos < sizeof(password)-1)
- password[pos++] = c;
- break;
- }
- }
+ ret = process_userpass_input(in, inlen);
+ } while (ret == 0);
+ if (ret < 0)
+ cleanup_exit(0);
c_write_str("\r\n");
}
}
logevent("Sent password");
type = AUTH_TYPE_PASSWORD;
} else if (method == AUTH_KEYBOARD_INTERACTIVE) {
- ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
- ssh2_pkt_adduint32(num_prompts);
- ssh2_pkt_addstring(password);
- memset(password, 0, sizeof(password));
- ssh2_pkt_send();
+ if (curr_prompt == 0) {
+ ssh2_pkt_init(SSH2_MSG_USERAUTH_INFO_RESPONSE);
+ ssh2_pkt_adduint32(num_prompts);
+ }
+ if (need_pw) { /* only add pw if we just got one! */
+ ssh2_pkt_addstring(password);
+ memset(password, 0, sizeof(password));
+ curr_prompt++;
+ }
+ if (curr_prompt >= num_prompts) {
+ ssh2_pkt_send();
+ } else {
+ /*
+ * If there are prompts remaining, we set
+ * `gotit' so that we won't attempt to get
+ * another packet. Then we go back round the
+ * loop and will end up retrieving another
+ * prompt out of the existing packet. Funky or
+ * what?
+ */
+ gotit = TRUE;
+ }
type = AUTH_TYPE_KEYBOARD_INTERACTIVE;
} else {
c_write_str
c->type = CHAN_SOCKDATA;
c->v.v2.remwindow = ssh2_pkt_getuint32();
c->v.v2.remmaxpkt = ssh2_pkt_getuint32();
- bufchain_init(&c->v.v2.outbuffer);
if (c->u.pfd.s)
pfd_confirm(c->u.pfd.s);
if (c->closes) {
c->closes = 0;
c->type = CHAN_SOCKDATA_DORMANT;/* identify channel type */
c->u.pfd.s = s;
+ bufchain_init(&c->v.v2.outbuffer);
add234(ssh_channels, c);
}
return c;
~mdw / sgt / putty / blobdiff