#define BUG_SSH2_HMAC 2
#define BUG_NEEDS_SSH1_PLAIN_PASSWORD 4
#define BUG_CHOKES_ON_RSA 8
+#define BUG_SSH2_RSA_PADDING 16
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;
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);
}
/*
+ * Helper function to add an SSH2 signature blob to a packet.
+ * Expects to be shown the public key blob as well as the signature
+ * blob. Normally works just like ssh2_pkt_addstring, but will
+ * fiddle with the signature packet if necessary for
+ * BUG_SSH2_RSA_PADDING.
+ */
+static void ssh2_add_sigblob(void *pkblob_v, int pkblob_len,
+ void *sigblob_v, int sigblob_len)
+{
+ unsigned char *pkblob = (unsigned char *)pkblob_v;
+ unsigned char *sigblob = (unsigned char *)sigblob_v;
+
+ /* dmemdump(pkblob, pkblob_len); */
+ /* dmemdump(sigblob, sigblob_len); */
+
+ /*
+ * See if this is in fact an ssh-rsa signature and a buggy
+ * server; otherwise we can just do this the easy way.
+ */
+ if ((ssh_remote_bugs & BUG_SSH2_RSA_PADDING) &&
+ (GET_32BIT(pkblob) == 7 && !memcmp(pkblob+4, "ssh-rsa", 7))) {
+ int pos, len, siglen;
+
+ /*
+ * Find the byte length of the modulus.
+ */
+
+ pos = 4+7; /* skip over "ssh-rsa" */
+ pos += 4 + GET_32BIT(pkblob+pos); /* skip over exponent */
+ len = GET_32BIT(pkblob+pos); /* find length of modulus */
+ pos += 4; /* find modulus itself */
+ while (len > 0 && pkblob[pos] == 0)
+ len--, pos++;
+ /* debug(("modulus length is %d\n", len)); */
+
+ /*
+ * Now find the signature integer.
+ */
+ pos = 4+7; /* skip over "ssh-rsa" */
+ siglen = GET_32BIT(sigblob+pos);
+ /* debug(("signature length is %d\n", siglen)); */
+
+ if (len != siglen) {
+ unsigned char newlen[4];
+ ssh2_pkt_addstring_start();
+ ssh2_pkt_addstring_data(sigblob, pos);
+ /* dmemdump(sigblob, pos); */
+ pos += 4; /* point to start of actual sig */
+ PUT_32BIT(newlen, len);
+ ssh2_pkt_addstring_data(newlen, 4);
+ /* dmemdump(newlen, 4); */
+ newlen[0] = 0;
+ while (len-- > siglen) {
+ ssh2_pkt_addstring_data(newlen, 1);
+ /* dmemdump(newlen, 1); */
+ }
+ ssh2_pkt_addstring_data(sigblob+pos, siglen);
+ /* dmemdump(sigblob+pos, siglen); */
+ return;
+ }
+
+ /* Otherwise fall through and do it the easy way. */
+ }
+
+ ssh2_pkt_addstring_start();
+ ssh2_pkt_addstring_data(sigblob, sigblob_len);
+}
+
+/*
* Examine the remote side's version string and compare it against
* a list of known buggy implementations.
*/
ssh_remote_bugs |= BUG_SSH2_HMAC;
logevent("We believe remote version has SSH2 HMAC bug");
}
+
+ if ((!strncmp(imp, "OpenSSH_2.", 10) && imp[10]>='5' && imp[10]<='9') ||
+ (!strncmp(imp, "OpenSSH_3.", 10) && imp[10]>='0' && imp[10]<='2')) {
+ /*
+ * These versions have the SSH2 RSA padding bug.
+ */
+ ssh_remote_bugs |= BUG_SSH2_RSA_PADDING;
+ logevent("We believe remote version has SSH2 RSA padding bug");
+ }
}
static int do_ssh_init(unsigned char c)
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)) {
/*
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];
* 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)) {
/*
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));
static int authed = FALSE;
void *r;
+ ssh_pkt_ctx &= ~SSH2_PKTCTX_AUTH_MASK;
ssh_pkt_ctx |= SSH2_PKTCTX_PUBLICKEY;
tried_agent = TRUE;
if (ret) {
if (ret[4] == SSH2_AGENT_SIGN_RESPONSE) {
logevent("Sending Pageant's response");
- ssh2_pkt_addstring_start();
- ssh2_pkt_addstring_data(ret + 9,
- GET_32BIT(ret +
- 5));
+ ssh2_add_sigblob(pkblob, pklen,
+ ret + 9, GET_32BIT(ret + 5));
ssh2_pkt_send();
authed = TRUE;
break;
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("\n");
+ }
+ if (inst_len > 0) {
c_write_untrusted(inst, inst_len);
+ c_write_str("\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);
ssh2_pkt_send();
type = AUTH_TYPE_NONE;
} else {
- unsigned char *blob, *sigdata;
- int blob_len, sigdata_len;
+ unsigned char *pkblob, *sigblob, *sigdata;
+ int pkblob_len, sigblob_len, sigdata_len;
/*
* We have loaded the private key and the server
ssh2_pkt_addstring("publickey"); /* method */
ssh2_pkt_addbool(TRUE);
ssh2_pkt_addstring(key->alg->name);
- blob = key->alg->public_blob(key->data, &blob_len);
+ pkblob = key->alg->public_blob(key->data, &pkblob_len);
ssh2_pkt_addstring_start();
- ssh2_pkt_addstring_data(blob, blob_len);
- sfree(blob);
+ ssh2_pkt_addstring_data(pkblob, pkblob_len);
/*
* The data to be signed is:
memcpy(sigdata + 4, ssh2_session_id, 20);
memcpy(sigdata + 24, pktout.data + 5,
pktout.length - 5);
- blob =
- key->alg->sign(key->data, sigdata, sigdata_len,
- &blob_len);
- ssh2_pkt_addstring_start();
- ssh2_pkt_addstring_data(blob, blob_len);
- sfree(blob);
+ sigblob = key->alg->sign(key->data, sigdata,
+ sigdata_len, &sigblob_len);
+ ssh2_add_sigblob(pkblob, pkblob_len,
+ sigblob, sigblob_len);
+ sfree(pkblob);
+ sfree(sigblob);
sfree(sigdata);
ssh2_pkt_send();
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;
projects / u / mdw / putty / blobdiff