if ((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)) \
fprintf(stderr, "%s\n", s); }
-#define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, sk_close(s), \
- s = NULL, connection_fatal msg )
+#define bombout(msg) ( ssh_state = SSH_STATE_CLOSED, \
+ (s ? sk_close(s), s = NULL : 0), \
+ connection_fatal msg )
#define SSH1_MSG_DISCONNECT 1 /* 0x1 */
#define SSH1_SMSG_PUBLIC_KEY 2 /* 0x2 */
#define SSH1_AUTH_TIS 5 /* 0x5 */
#define SSH1_AUTH_CCARD 16 /* 0x10 */
-#define SSH_AGENTC_REQUEST_RSA_IDENTITIES 1 /* 0x1 */
-#define SSH_AGENT_RSA_IDENTITIES_ANSWER 2 /* 0x2 */
-#define SSH_AGENTC_RSA_CHALLENGE 3 /* 0x3 */
-#define SSH_AGENT_RSA_RESPONSE 4 /* 0x4 */
-#define SSH_AGENT_FAILURE 5 /* 0x5 */
-#define SSH_AGENT_SUCCESS 6 /* 0x6 */
-#define SSH_AGENTC_ADD_RSA_IDENTITY 7 /* 0x7 */
-#define SSH_AGENTC_REMOVE_RSA_IDENTITY 8 /* 0x8 */
-
#define SSH2_MSG_DISCONNECT 1 /* 0x1 */
#define SSH2_MSG_IGNORE 2 /* 0x2 */
#define SSH2_MSG_UNIMPLEMENTED 3 /* 0x3 */
#define SSH2_MSG_NEWKEYS 21 /* 0x15 */
#define SSH2_MSG_KEXDH_INIT 30 /* 0x1e */
#define SSH2_MSG_KEXDH_REPLY 31 /* 0x1f */
+#define SSH2_MSG_KEX_DH_GEX_REQUEST 30 /* 0x1e */
+#define SSH2_MSG_KEX_DH_GEX_GROUP 31 /* 0x1f */
+#define SSH2_MSG_KEX_DH_GEX_INIT 32 /* 0x20 */
+#define SSH2_MSG_KEX_DH_GEX_REPLY 33 /* 0x21 */
#define SSH2_MSG_USERAUTH_REQUEST 50 /* 0x32 */
#define SSH2_MSG_USERAUTH_FAILURE 51 /* 0x33 */
#define SSH2_MSG_USERAUTH_SUCCESS 52 /* 0x34 */
#define SSH2_EXTENDED_DATA_STDERR 1 /* 0x1 */
+/*
+ * Various remote-bug flags.
+ */
+#define BUG_CHOKES_ON_SSH1_IGNORE 1
+#define BUG_SSH2_HMAC 2
+
#define GET_32BIT(cp) \
(((unsigned long)(unsigned char)(cp)[0] << 24) | \
((unsigned long)(unsigned char)(cp)[1] << 16) | \
#define crWaitUntil(c) do { crReturn(0); } while (!(c))
#define crWaitUntilV(c) do { crReturnV; } while (!(c))
-extern const struct ssh_cipher ssh_3des;
-extern const struct ssh_cipher ssh_3des_ssh2;
-extern const struct ssh_cipher ssh_des;
-extern const struct ssh_cipher ssh_blowfish_ssh1;
-extern const struct ssh_cipher ssh_blowfish_ssh2;
-
extern char *x11_init (Socket *, char *, void *);
extern void x11_close (Socket);
extern void x11_send (Socket , char *, int);
* SSH1. (3DES uses outer chaining; Blowfish has the opposite
* endianness and different-sized keys.)
*/
-const static struct ssh_cipher *ciphers[] = { &ssh_blowfish_ssh2, &ssh_3des_ssh2 };
-
-extern const struct ssh_kex ssh_diffiehellman;
-const static struct ssh_kex *kex_algs[] = { &ssh_diffiehellman };
+const static struct ssh2_ciphers *ciphers[] = {
+ &ssh2_aes,
+ &ssh2_blowfish,
+ &ssh2_3des,
+};
-extern const struct ssh_signkey ssh_dss;
-const static struct ssh_signkey *hostkey_algs[] = { &ssh_dss };
+const static struct ssh_kex *kex_algs[] = {
+ &ssh_diffiehellman_gex,
+ &ssh_diffiehellman };
-extern const struct ssh_mac ssh_md5, ssh_sha1, ssh_sha1_buggy;
+const static struct ssh_signkey *hostkey_algs[] = { &ssh_rsa, &ssh_dss };
static void nullmac_key(unsigned char *key) { }
static void nullmac_generate(unsigned char *blk, int len, unsigned long seq) { }
unsigned char **outblock, int *outlen) {
return 0;
}
+static int ssh_comp_none_disable(void) { return 0; }
const static struct ssh_compress ssh_comp_none = {
"none",
ssh_comp_none_init, ssh_comp_none_block,
- ssh_comp_none_init, ssh_comp_none_block
+ ssh_comp_none_init, ssh_comp_none_block,
+ ssh_comp_none_disable
};
extern const struct ssh_compress ssh_zlib;
const static struct ssh_compress *compressions[] = {
static int ssh1_compressing;
static int ssh_agentfwd_enabled;
static int ssh_X11_fwd_enabled;
+static int ssh_remote_bugs;
static const struct ssh_cipher *cipher = NULL;
-static const struct ssh_cipher *cscipher = NULL;
-static const struct ssh_cipher *sccipher = NULL;
+static const struct ssh2_cipher *cscipher = NULL;
+static const struct ssh2_cipher *sccipher = NULL;
static const struct ssh_mac *csmac = NULL;
static const struct ssh_mac *scmac = NULL;
static const struct ssh_compress *cscomp = NULL;
static const struct ssh_compress *sccomp = NULL;
static const struct ssh_kex *kex = NULL;
static const struct ssh_signkey *hostkey = NULL;
-int (*ssh_get_password)(const char *prompt, char *str, int maxlen) = 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 struct Packet pktin = { 0, 0, NULL, NULL, 0 };
static struct Packet pktout = { 0, 0, NULL, NULL, 0 };
+static unsigned char *deferred_send_data = NULL;
+static int deferred_len = 0, deferred_size = 0;
static int ssh_version;
static void (*ssh_protocol)(unsigned char *in, int inlen, int ispkt);
from_backend(1, buf, len);
}
+static void c_write_str (char *buf) {
+ c_write(buf, strlen(buf));
+}
+
/*
* Collect incoming data in the incoming packet buffer.
* Decipher and verify the packet when it is completely read.
pktout.type = type;
}
-static void s_wrpkt(void) {
+static int s_wrpkt_prepare(void) {
int pad, len, biglen, i;
unsigned long crc;
pktout.body[-1] = pktout.type;
+#if 0
+ debug(("Packet payload pre-compression:\n"));
+ for (i = -1; i < pktout.length; i++)
+ debug((" %02x", (unsigned char)pktout.body[i]));
+ debug(("\r\n"));
+#endif
+
if (ssh1_compressing) {
unsigned char *compblk;
int complen;
-#if 0
- debug(("Packet payload pre-compression:\n"));
- for (i = -1; i < pktout.length; i++)
- debug((" %02x", (unsigned char)pktout.body[i]));
- debug(("\r\n"));
-#endif
zlib_compress_block(pktout.body-1, pktout.length+1,
&compblk, &complen);
ssh1_pktout_size(complen-1);
if (cipher)
cipher->encrypt(pktout.data+4, biglen);
- sk_write(s, pktout.data, biglen+4);
+ return biglen+4;
+}
+
+static void s_wrpkt(void) {
+ int len;
+ len = s_wrpkt_prepare();
+ sk_write(s, pktout.data, len);
+}
+
+static void s_wrpkt_defer(void) {
+ int len;
+ len = s_wrpkt_prepare();
+ if (deferred_len + len > deferred_size) {
+ deferred_size = deferred_len + len + 128;
+ deferred_send_data = srealloc(deferred_send_data, deferred_size);
+ }
+ memcpy(deferred_send_data+deferred_len, pktout.data, len);
+ deferred_len += len;
}
/*
- * Construct a packet with the specified contents and
- * send it to the server.
+ * Construct a packet with the specified contents.
*/
-static void send_packet(int pkttype, ...)
+static void construct_packet(int pkttype, va_list ap1, va_list ap2)
{
- va_list args;
unsigned char *p, *argp, argchar;
unsigned long argint;
int pktlen, argtype, arglen;
Bignum bn;
pktlen = 0;
- va_start(args, pkttype);
- while ((argtype = va_arg(args, int)) != PKT_END) {
+ while ((argtype = va_arg(ap1, int)) != PKT_END) {
switch (argtype) {
case PKT_INT:
- (void) va_arg(args, int);
+ (void) va_arg(ap1, int);
pktlen += 4;
break;
case PKT_CHAR:
- (void) va_arg(args, char);
+ (void) va_arg(ap1, char);
pktlen++;
break;
case PKT_DATA:
- (void) va_arg(args, unsigned char *);
- arglen = va_arg(args, int);
+ (void) va_arg(ap1, unsigned char *);
+ arglen = va_arg(ap1, int);
pktlen += arglen;
break;
case PKT_STR:
- argp = va_arg(args, unsigned char *);
+ argp = va_arg(ap1, unsigned char *);
arglen = strlen(argp);
pktlen += 4 + arglen;
break;
case PKT_BIGNUM:
- bn = va_arg(args, Bignum);
+ bn = va_arg(ap1, Bignum);
pktlen += ssh1_bignum_length(bn);
break;
default:
assert(0);
}
}
- va_end(args);
s_wrpkt_start(pkttype, pktlen);
p = pktout.body;
- va_start(args, pkttype);
- while ((argtype = va_arg(args, int)) != PKT_END) {
+ while ((argtype = va_arg(ap2, int)) != PKT_END) {
switch (argtype) {
case PKT_INT:
- argint = va_arg(args, int);
+ argint = va_arg(ap2, int);
PUT_32BIT(p, argint);
p += 4;
break;
case PKT_CHAR:
- argchar = va_arg(args, unsigned char);
+ argchar = va_arg(ap2, unsigned char);
*p = argchar;
p++;
break;
case PKT_DATA:
- argp = va_arg(args, unsigned char *);
- arglen = va_arg(args, int);
+ argp = va_arg(ap2, unsigned char *);
+ arglen = va_arg(ap2, int);
memcpy(p, argp, arglen);
p += arglen;
break;
case PKT_STR:
- argp = va_arg(args, unsigned char *);
+ argp = va_arg(ap2, unsigned char *);
arglen = strlen(argp);
PUT_32BIT(p, arglen);
memcpy(p + 4, argp, arglen);
p += 4 + arglen;
break;
case PKT_BIGNUM:
- bn = va_arg(args, Bignum);
+ bn = va_arg(ap2, Bignum);
p += ssh1_write_bignum(p, bn);
break;
}
}
- va_end(args);
+}
+static void send_packet(int pkttype, ...) {
+ va_list ap1, ap2;
+ va_start(ap1, pkttype);
+ va_start(ap2, pkttype);
+ construct_packet(pkttype, ap1, ap2);
s_wrpkt();
}
+static void defer_packet(int pkttype, ...) {
+ va_list ap1, ap2;
+ va_start(ap1, pkttype);
+ va_start(ap2, pkttype);
+ construct_packet(pkttype, ap1, ap2);
+ s_wrpkt_defer();
+}
+
static int ssh_versioncmp(char *a, char *b) {
char *ae, *be;
unsigned long av, bv;
/*
- * Utility routine for putting an SSH-protocol `string' into a SHA
- * state.
+ * Utility routines for putting an SSH-protocol `string' and
+ * `uint32' into a SHA state.
*/
#include <stdio.h>
static void sha_string(SHA_State *s, void *str, int len) {
SHA_Bytes(s, str, len);
}
+static void sha_uint32(SHA_State *s, unsigned i) {
+ unsigned char intblk[4];
+ PUT_32BIT(intblk, i);
+ SHA_Bytes(s, intblk, 4);
+}
+
/*
* SSH2 packet construction functions.
*/
}
static char *ssh2_mpint_fmt(Bignum b, int *len) {
unsigned char *p;
- int i, n = b[0];
- p = smalloc(n * 2 + 1);
+ int i, n = (ssh1_bignum_bitcount(b)+7)/8;
+ p = smalloc(n + 1);
if (!p)
fatalbox("out of memory");
p[0] = 0;
- for (i = 0; i < n; i++) {
- p[i*2+1] = (b[n-i] >> 8) & 0xFF;
- p[i*2+2] = (b[n-i] ) & 0xFF;
- }
+ for (i = 1; i <= n; i++)
+ p[i] = bignum_byte(b, n-i);
i = 0;
- while (p[i] == 0 && (p[i+1] & 0x80) == 0)
+ while (i <= n && p[i] == 0 && (p[i+1] & 0x80) == 0)
i++;
- memmove(p, p+i, n*2+1-i);
- *len = n*2+1-i;
+ memmove(p, p+i, n+1-i);
+ *len = n+1-i;
return p;
}
static void ssh2_pkt_addmp(Bignum b) {
ssh2_pkt_addstring_data(p, len);
sfree(p);
}
-static void ssh2_pkt_send(void) {
+
+/*
+ * Construct an SSH2 final-form packet: compress it, encrypt it,
+ * put the MAC on it. Final packet, ready to be sent, is stored in
+ * pktout.data. Total length is returned.
+ */
+static int ssh2_pkt_construct(void) {
int cipherblk, maclen, padding, i;
static unsigned long outgoing_sequence = 0;
* Add padding. At least four bytes, and must also bring total
* length (minus MAC) up to a multiple of the block size.
*/
- cipherblk = cipher ? cipher->blksize : 8; /* block size */
+ cipherblk = cscipher ? cscipher->blksize : 8; /* block size */
cipherblk = cipherblk < 8 ? 8 : cipherblk; /* or 8 if blksize < 8 */
padding = 4;
padding += (cipherblk - (pktout.length + padding) % cipherblk) % cipherblk;
if (cscipher)
cscipher->encrypt(pktout.data, pktout.length + padding);
- sk_write(s, pktout.data, pktout.length + padding + maclen);
+ /* Ready-to-send packet starts at pktout.data. We return length. */
+ return pktout.length + padding + maclen;
+}
+
+/*
+ * Construct and send an SSH2 packet immediately.
+ */
+static void ssh2_pkt_send(void) {
+ int len = ssh2_pkt_construct();
+ sk_write(s, pktout.data, len);
+}
+
+/*
+ * Construct an SSH2 packet and add it to a deferred data block.
+ * Useful for sending multiple packets in a single sk_write() call,
+ * to prevent a traffic-analysing listener from being able to work
+ * out the length of any particular packet (such as the password
+ * packet).
+ *
+ * Note that because SSH2 sequence-numbers its packets, this can
+ * NOT be used as an m4-style `defer' allowing packets to be
+ * constructed in one order and sent in another.
+ */
+static void ssh2_pkt_defer(void) {
+ int len = ssh2_pkt_construct();
+ if (deferred_len + len > deferred_size) {
+ deferred_size = deferred_len + len + 128;
+ deferred_send_data = srealloc(deferred_send_data, deferred_size);
+ }
+ memcpy(deferred_send_data+deferred_len, pktout.data, len);
+ deferred_len += len;
+}
+
+/*
+ * Send the whole deferred data block constructed by
+ * ssh2_pkt_defer() or SSH1's defer_packet().
+ */
+static void ssh_pkt_defersend(void) {
+ sk_write(s, deferred_send_data, deferred_len);
+ deferred_len = deferred_size = 0;
+ sfree(deferred_send_data);
+ deferred_send_data = NULL;
}
#if 0
pktin.savedpos += 4;
return value;
}
+static int ssh2_pkt_getbool(void) {
+ unsigned long value;
+ if (pktin.length - pktin.savedpos < 1)
+ return 0; /* arrgh, no way to decline (FIXME?) */
+ value = pktin.data[pktin.savedpos] != 0;
+ pktin.savedpos++;
+ return value;
+}
static void ssh2_pkt_getstring(char **p, int *length) {
*p = NULL;
if (pktin.length - pktin.savedpos < 4)
}
static Bignum ssh2_pkt_getmp(void) {
char *p;
- int i, j, length;
+ int length;
Bignum b;
ssh2_pkt_getstring(&p, &length);
bombout(("internal error: Can't handle negative mpints"));
return NULL;
}
- b = newbn((length+1)/2);
- for (i = 0; i < length; i++) {
- j = length - 1 - i;
- if (j & 1)
- b[j/2+1] |= ((unsigned char)p[i]) << 8;
- else
- b[j/2+1] |= ((unsigned char)p[i]);
- }
- while (b[0] > 1 && b[b[0]] == 0) b[0]--;
+ b = bignum_from_bytes(p, length);
return b;
}
+/*
+ * Examine the remote side's version string and compare it against
+ * a list of known buggy implementations.
+ */
+static void ssh_detect_bugs(char *vstring) {
+ char *imp; /* pointer to implementation part */
+ imp = vstring;
+ imp += strcspn(imp, "-");
+ imp += strcspn(imp, "-");
+
+ ssh_remote_bugs = 0;
+
+ if (!strcmp(imp, "1.2.18") || !strcmp(imp, "1.2.19") ||
+ !strcmp(imp, "1.2.20") || !strcmp(imp, "1.2.21") ||
+ !strcmp(imp, "1.2.22")) {
+ /*
+ * These versions don't support SSH1_MSG_IGNORE, so we have
+ * to use a different defence against password length
+ * sniffing.
+ */
+ ssh_remote_bugs |= BUG_CHOKES_ON_SSH1_IGNORE;
+ logevent("We believe remote version has SSH1 ignore bug");
+ }
+
+ if (!strncmp(imp, "2.1.0", 5) || !strncmp(imp, "2.0.", 4) ||
+ !strncmp(imp, "2.2.0", 5) || !strncmp(imp, "2.3.0", 5) ||
+ !strncmp(imp, "2.1 ", 4)) {
+ /*
+ * These versions have the HMAC bug.
+ */
+ ssh_remote_bugs |= BUG_SSH2_HMAC;
+ logevent("We believe remote version has SSH2 HMAC bug");
+ }
+}
+
static int do_ssh_init(unsigned char c) {
static char *vsp;
static char version[10];
*vsp = 0;
sprintf(vlog, "Server version: %s", vstring);
+ ssh_detect_bugs(vstring);
vlog[strcspn(vlog, "\r\n")] = '\0';
logevent(vlog);
crFinishV;
}
-static int ssh_receive(Socket skt, int urgent, char *data, int len) {
- if (urgent==3) {
+static int ssh_closing (Plug plug, char *error_msg, int error_code, int calling_back) {
+ ssh_state = SSH_STATE_CLOSED;
+ sk_close(s);
+ s = NULL;
+ if (error_msg) {
/* A socket error has occurred. */
- ssh_state = SSH_STATE_CLOSED;
- s = NULL;
- connection_fatal(data);
- len = 0;
- }
- if (!len) {
- /* Connection has closed. */
- ssh_state = SSH_STATE_CLOSED;
- sk_close(s);
- s = NULL;
- return 0;
+ connection_fatal (error_msg);
+ } else {
+ /* Otherwise, the remote side closed the connection normally. */
}
+ return 0;
+}
+
+static int ssh_receive(Plug plug, int urgent, char *data, int len) {
ssh_gotdata (data, len);
if (ssh_state == SSH_STATE_CLOSED) {
if (s) {
*/
static char *connect_to_host(char *host, int port, char **realhost)
{
+ static struct plug_function_table fn_table = {
+ ssh_closing,
+ ssh_receive
+ }, *fn_table_ptr = &fn_table;
+
SockAddr addr;
char *err;
#ifdef FWHACK
/*
* Open socket.
*/
- s = sk_new(addr, port, 0, ssh_receive);
+ s = sk_new(addr, port, 0, 1, &fn_table_ptr);
if ( (err = sk_socket_error(s)) )
return err;
logevent("Encrypted session key");
- cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
- cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES :
- SSH_CIPHER_3DES;
+ switch (cfg.cipher) {
+ case CIPHER_BLOWFISH: cipher_type = SSH_CIPHER_BLOWFISH; break;
+ case CIPHER_DES: cipher_type = SSH_CIPHER_DES; break;
+ case CIPHER_3DES: cipher_type = SSH_CIPHER_3DES; break;
+ case CIPHER_AES:
+ c_write_str("AES not supported in SSH1, falling back to 3DES\r\n");
+ cipher_type = SSH_CIPHER_3DES;
+ break;
+ }
if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
- c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
+ c_write_str("Selected cipher not supported, falling back to 3DES\r\n");
cipher_type = SSH_CIPHER_3DES;
}
switch (cipher_type) {
static int pos = 0;
static char c;
if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
- c_write("login as: ", 10);
- ssh_send_ok = 1;
- while (pos >= 0) {
- 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("\b \b", 3);
- pos--;
- }
- break;
- case 21: case 27:
- while (pos > 0) {
- c_write("\b \b", 3);
- pos--;
- }
- break;
- case 3: case 4:
- random_save_seed();
- exit(0);
- break;
- default:
- if (((c >= ' ' && c <= '~') ||
- ((unsigned char)c >= 160)) && pos < 40) {
- username[pos++] = c;
- c_write(&c, 1);
- }
- break;
- }
- }
- c_write("\r\n", 2);
- username[strcspn(username, "\n\r")] = '\0';
- } else {
+ if (ssh_get_line) {
+ if (!ssh_get_line("login as: ",
+ username, sizeof(username), FALSE)) {
+ /*
+ * get_line failed to get a username.
+ * Terminate.
+ */
+ logevent("No username provided. Abandoning session.");
+ ssh_state = SSH_STATE_CLOSED;
+ crReturn(1);
+ }
+ } else {
+ c_write_str("login as: ");
+ ssh_send_ok = 1;
+ while (pos >= 0) {
+ 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:
+ random_save_seed();
+ exit(0);
+ break;
+ default:
+ if (((c >= ' ' && c <= '~') ||
+ ((unsigned char)c >= 160)) && pos < 40) {
+ username[pos++] = c;
+ c_write(&c, 1);
+ }
+ break;
+ }
+ }
+ c_write_str("\r\n");
+ username[strcspn(username, "\n\r")] = '\0';
+ }
+ } else {
strncpy(username, cfg.username, 99);
username[99] = '\0';
}
if (flags & FLAG_INTERACTIVE &&
(!((flags & FLAG_STDERR) && (flags & FLAG_VERBOSE)))) {
strcat(userlog, "\r\n");
- c_write(userlog, strlen(userlog));
+ c_write_str(userlog);
}
}
}
/* Request the keys held by the agent. */
PUT_32BIT(request, 1);
- request[4] = SSH_AGENTC_REQUEST_RSA_IDENTITIES;
+ request[4] = SSH1_AGENTC_REQUEST_RSA_IDENTITIES;
agent_query(request, 5, &r, &responselen);
response = (unsigned char *)r;
if (response) {
p = response + 5;
nkeys = GET_32BIT(p); p += 4;
- { char buf[64]; sprintf(buf, "Pageant has %d keys", nkeys);
+ { char buf[64]; sprintf(buf, "Pageant has %d SSH1 keys", nkeys);
logevent(buf); }
for (i = 0; i < nkeys; i++) {
static struct RSAKey key;
agentreq = smalloc(4 + len);
PUT_32BIT(agentreq, len);
q = agentreq + 4;
- *q++ = SSH_AGENTC_RSA_CHALLENGE;
+ *q++ = SSH1_AGENTC_RSA_CHALLENGE;
PUT_32BIT(q, ssh1_bignum_bitcount(key.modulus));
q += 4;
q += ssh1_write_bignum(q, key.exponent);
agent_query(agentreq, len+4, &ret, &retlen);
sfree(agentreq);
if (ret) {
- if (ret[4] == SSH_AGENT_RSA_RESPONSE) {
+ if (ret[4] == SSH1_AGENT_RSA_RESPONSE) {
logevent("Sending Pageant's response");
send_packet(SSH1_CMSG_AUTH_RSA_RESPONSE,
PKT_DATA, ret+5, 16, PKT_END);
if (pktin.type == SSH1_SMSG_SUCCESS) {
logevent("Pageant's response accepted");
if (flags & FLAG_VERBOSE) {
- c_write("Authenticated using RSA key \"",
- 29);
+ c_write_str("Authenticated using RSA key \"");
c_write(commentp, commentlen);
- c_write("\" from agent\r\n", 14);
+ c_write_str("\" from agent\r\n");
}
authed = TRUE;
} else
if (pktin.type != SSH1_SMSG_AUTH_TIS_CHALLENGE) {
logevent("TIS authentication declined");
if (flags & FLAG_INTERACTIVE)
- c_write("TIS authentication refused.\r\n", 29);
+ c_write_str("TIS authentication refused.\r\n");
} else {
int challengelen = ((pktin.body[0] << 24) |
(pktin.body[1] << 16) |
crWaitUntil(ispkt);
if (pktin.type != SSH1_SMSG_AUTH_CCARD_CHALLENGE) {
logevent("CryptoCard authentication declined");
- c_write("CryptoCard authentication refused.\r\n", 29);
+ c_write_str("CryptoCard authentication refused.\r\n");
} else {
int challengelen = ((pktin.body[0] << 24) |
(pktin.body[1] << 16) |
if (pwpkt_type == SSH1_CMSG_AUTH_RSA) {
char *comment = NULL;
if (flags & FLAG_VERBOSE)
- c_write("Trying public key authentication.\r\n", 35);
+ c_write_str("Trying public key authentication.\r\n");
if (!rsakey_encrypted(cfg.keyfile, &comment)) {
if (flags & FLAG_VERBOSE)
- c_write("No passphrase required.\r\n", 25);
+ c_write_str("No passphrase required.\r\n");
goto tryauth;
}
sprintf(prompt, "Passphrase for key \"%.100s\": ", comment);
sfree(comment);
}
- if (ssh_get_password) {
- if (!ssh_get_password(prompt, password, sizeof(password))) {
+ if (ssh_get_line) {
+ if (!ssh_get_line(prompt, password, sizeof(password), TRUE)) {
/*
- * get_password failed to get a password (for
- * example because one was supplied on the command
- * line which has already failed to work).
- * Terminate.
+ * get_line failed to get a password (for example
+ * because one was supplied on the command line
+ * which has already failed to work). Terminate.
*/
logevent("No more passwords to try");
ssh_state = SSH_STATE_CLOSED;
crReturn(1);
}
} else {
- c_write(prompt, strlen(prompt));
+ c_write_str(prompt);
pos = 0;
ssh_send_ok = 1;
while (pos >= 0) {
break;
}
}
- c_write("\r\n", 2);
+ c_write_str("\r\n");
}
tryauth:
static unsigned char buffer[32];
tried_publickey = 1;
- i = loadrsakey(cfg.keyfile, &pubkey, NULL, password);
+ i = loadrsakey(cfg.keyfile, &pubkey, password);
if (i == 0) {
- c_write("Couldn't load public key from ", 30);
- c_write(cfg.keyfile, strlen(cfg.keyfile));
- c_write(".\r\n", 3);
+ c_write_str("Couldn't load public key from ");
+ c_write_str(cfg.keyfile);
+ c_write_str(".\r\n");
continue; /* go and try password */
}
if (i == -1) {
- c_write("Wrong passphrase.\r\n", 19);
+ c_write_str("Wrong passphrase.\r\n");
tried_publickey = 0;
continue; /* try again */
}
crWaitUntil(ispkt);
if (pktin.type == SSH1_SMSG_FAILURE) {
- c_write("Server refused our public key.\r\n", 32);
+ c_write_str("Server refused our public key.\r\n");
continue; /* go and try password */
}
if (pktin.type != SSH1_SMSG_AUTH_RSA_CHALLENGE) {
response = rsadecrypt(challenge, &pubkey);
freebn(pubkey.private_exponent); /* burn the evidence */
- for (i = 0; i < 32; i += 2) {
- buffer[i] = response[16-i/2] >> 8;
- buffer[i+1] = response[16-i/2] & 0xFF;
+ for (i = 0; i < 32; i++) {
+ buffer[i] = bignum_byte(response, 31-i);
}
MD5Init(&md5c);
crWaitUntil(ispkt);
if (pktin.type == SSH1_SMSG_FAILURE) {
if (flags & FLAG_VERBOSE)
- c_write("Failed to authenticate with our public key.\r\n",
- 45);
+ c_write_str("Failed to authenticate with our public key.\r\n");
continue; /* go and try password */
} else if (pktin.type != SSH1_SMSG_SUCCESS) {
bombout(("Bizarre response to RSA authentication response"));
break; /* we're through! */
} else {
- send_packet(pwpkt_type, PKT_STR, password, PKT_END);
+ if (pwpkt_type == SSH1_CMSG_AUTH_PASSWORD) {
+ /*
+ * Defence against traffic analysis: we send a
+ * whole bunch of packets containing strings of
+ * different lengths. One of these strings is the
+ * password, in a SSH1_CMSG_AUTH_PASSWORD packet.
+ * The others are all random data in
+ * SSH1_MSG_IGNORE packets. This way a passive
+ * listener can't tell which is the password, and
+ * hence can't deduce the password length.
+ *
+ * Anybody with a password length greater than 16
+ * bytes is going to have enough entropy in their
+ * password that a listener won't find it _that_
+ * much help to know how long it is. So what we'll
+ * do is:
+ *
+ * - if password length < 16, we send 15 packets
+ * containing string lengths 1 through 15
+ *
+ * - otherwise, we let N be the nearest multiple
+ * of 8 below the password length, and send 8
+ * packets containing string lengths N through
+ * N+7. This won't obscure the order of
+ * magnitude of the password length, but it will
+ * introduce a bit of extra uncertainty.
+ *
+ * A few servers (the old 1.2.18 through 1.2.22)
+ * can't deal with SSH1_MSG_IGNORE. For these
+ * servers, we need an alternative defence. We make
+ * use of the fact that the password is interpreted
+ * as a C string: so we can append a NUL, then some
+ * random data.
+ */
+ if (ssh_remote_bugs & BUG_CHOKES_ON_SSH1_IGNORE) {
+ char string[64];
+ char *s;
+ int len;
+
+ len = strlen(password);
+ if (len < sizeof(string)) {
+ s = string;
+ strcpy(string, password);
+ len++; /* cover the zero byte */
+ while (len < sizeof(string)) {
+ string[len++] = (char)random_byte();
+ }
+ } else {
+ s = password;
+ }
+ send_packet(pwpkt_type, PKT_INT, len,
+ PKT_DATA, s, len, PKT_END);
+ } else {
+ int bottom, top, pwlen, i;
+ char *randomstr;
+
+ pwlen = strlen(password);
+ if (pwlen < 16) {
+ bottom = 0; /* zero length passwords are OK! :-) */
+ top = 15;
+ } else {
+ bottom = pwlen &~ 7;
+ top = bottom + 7;
+ }
+
+ assert(pwlen >= bottom && pwlen <= top);
+
+ randomstr = smalloc(top+1);
+
+ for (i = bottom; i <= top; i++) {
+ if (i == pwlen)
+ defer_packet(pwpkt_type, PKT_STR, password, PKT_END);
+ else {
+ for (j = 0; j < i; j++) {
+ do {
+ randomstr[j] = random_byte();
+ } while (randomstr[j] == '\0');
+ }
+ randomstr[i] = '\0';
+ defer_packet(SSH1_MSG_IGNORE,
+ PKT_STR, randomstr, PKT_END);
+ }
+ }
+ ssh_pkt_defersend();
+ }
+ } else {
+ send_packet(pwpkt_type, PKT_STR, password, PKT_END);
+ }
}
logevent("Sent password");
memset(password, 0, strlen(password));
crWaitUntil(ispkt);
if (pktin.type == SSH1_SMSG_FAILURE) {
if (flags & FLAG_VERBOSE)
- c_write("Access denied\r\n", 15);
+ c_write_str("Access denied\r\n");
logevent("Authentication refused");
} else if (pktin.type == SSH1_MSG_DISCONNECT) {
logevent("Received disconnect request");
bombout(("Protocol confusion"));
crReturnV;
} else if (pktin.type == SSH1_SMSG_FAILURE) {
- c_write("Server refused to allocate pty\r\n", 32);
+ c_write_str("Server refused to allocate pty\r\n");
ssh_editing = ssh_echoing = 1;
}
logevent("Allocated pty");
bombout(("Protocol confusion"));
crReturnV;
} else if (pktin.type == SSH1_SMSG_FAILURE) {
- c_write("Server refused to compress\r\n", 32);
+ c_write_str("Server refused to compress\r\n");
}
logevent("Started compression");
ssh1_compressing = TRUE;
/*
* SSH2 key creation method.
*/
-static void ssh2_mkkey(Bignum K, char *H, char chr, char *keyspace) {
+static void ssh2_mkkey(Bignum K, char *H, char *sessid, char chr, char *keyspace) {
SHA_State s;
/* First 20 bytes. */
SHA_Init(&s);
sha_mpint(&s, K);
SHA_Bytes(&s, H, 20);
SHA_Bytes(&s, &chr, 1);
- SHA_Bytes(&s, H, 20);
+ SHA_Bytes(&s, sessid, 20);
SHA_Final(&s, keyspace);
/* Next 20 bytes. */
SHA_Init(&s);
*/
static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
{
- static int i, len;
+ static int i, j, len, nbits, pbits;
static char *str;
- static Bignum e, f, K;
+ static Bignum p, g, e, f, K;
+ static int kex_init_value, kex_reply_value;
static const struct ssh_mac **maclist;
static int nmacs;
- static const struct ssh_cipher *cscipher_tobe = NULL;
- static const struct ssh_cipher *sccipher_tobe = NULL;
+ static const struct ssh2_cipher *cscipher_tobe = NULL;
+ static const struct ssh2_cipher *sccipher_tobe = NULL;
static const struct ssh_mac *csmac_tobe = NULL;
static const struct ssh_mac *scmac_tobe = NULL;
static const struct ssh_compress *cscomp_tobe = NULL;
static void *hkey; /* actual host key */
static unsigned char exchange_hash[20];
static unsigned char keyspace[40];
- static const struct ssh_cipher *preferred_cipher;
+ static const struct ssh2_ciphers *preferred_cipher;
static const struct ssh_compress *preferred_comp;
static int first_kex;
* Set up the preferred cipher and compression.
*/
if (cfg.cipher == CIPHER_BLOWFISH) {
- preferred_cipher = &ssh_blowfish_ssh2;
+ preferred_cipher = &ssh2_blowfish;
} else if (cfg.cipher == CIPHER_DES) {
logevent("Single DES not supported in SSH2; using 3DES");
- preferred_cipher = &ssh_3des_ssh2;
+ preferred_cipher = &ssh2_3des;
} else if (cfg.cipher == CIPHER_3DES) {
- preferred_cipher = &ssh_3des_ssh2;
+ preferred_cipher = &ssh2_3des;
+ } else if (cfg.cipher == CIPHER_AES) {
+ preferred_cipher = &ssh2_aes;
} else {
/* Shouldn't happen, but we do want to initialise to _something_. */
- preferred_cipher = &ssh_3des_ssh2;
+ preferred_cipher = &ssh2_3des;
}
if (cfg.compression)
preferred_comp = &ssh_zlib;
/*
* Be prepared to work around the buggy MAC problem.
*/
- if (cfg.buggymac)
+ if (cfg.buggymac || (ssh_remote_bugs & BUG_SSH2_HMAC))
maclist = buggymacs, nmacs = lenof(buggymacs);
else
maclist = macs, nmacs = lenof(macs);
/* List client->server encryption algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < lenof(ciphers)+1; i++) {
- const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
- ssh2_pkt_addstring_str(c->name);
- if (i < lenof(ciphers))
- ssh2_pkt_addstring_str(",");
+ const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
+ for (j = 0; j < c->nciphers; j++) {
+ ssh2_pkt_addstring_str(c->list[j]->name);
+ if (i < lenof(ciphers) || j < c->nciphers-1)
+ ssh2_pkt_addstring_str(",");
+ }
}
/* List server->client encryption algorithms. */
ssh2_pkt_addstring_start();
for (i = 0; i < lenof(ciphers)+1; i++) {
- const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
- ssh2_pkt_addstring_str(c->name);
- if (i < lenof(ciphers))
- ssh2_pkt_addstring_str(",");
+ const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
+ for (j = 0; j < c->nciphers; j++) {
+ ssh2_pkt_addstring_str(c->list[j]->name);
+ if (i < lenof(ciphers) || j < c->nciphers-1)
+ ssh2_pkt_addstring_str(",");
+ }
}
/* List client->server MAC algorithms. */
ssh2_pkt_addstring_start();
}
ssh2_pkt_getstring(&str, &len); /* client->server cipher */
for (i = 0; i < lenof(ciphers)+1; i++) {
- const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
- if (in_commasep_string(c->name, str, len)) {
- cscipher_tobe = c;
- break;
+ const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
+ for (j = 0; j < c->nciphers; j++) {
+ if (in_commasep_string(c->list[j]->name, str, len)) {
+ cscipher_tobe = c->list[j];
+ break;
+ }
}
+ if (cscipher_tobe)
+ break;
}
ssh2_pkt_getstring(&str, &len); /* server->client cipher */
for (i = 0; i < lenof(ciphers)+1; i++) {
- const struct ssh_cipher *c = i==0 ? preferred_cipher : ciphers[i-1];
- if (in_commasep_string(c->name, str, len)) {
- sccipher_tobe = c;
- break;
+ const struct ssh2_ciphers *c = i==0 ? preferred_cipher : ciphers[i-1];
+ for (j = 0; j < c->nciphers; j++) {
+ if (in_commasep_string(c->list[j]->name, str, len)) {
+ sccipher_tobe = c->list[j];
+ break;
+ }
}
+ if (sccipher_tobe)
+ break;
}
ssh2_pkt_getstring(&str, &len); /* client->server mac */
for (i = 0; i < nmacs; i++) {
}
/*
- * Currently we only support Diffie-Hellman and DSS, so let's
- * bomb out if those aren't selected.
+ * Work out the number of bits of key we will need from the key
+ * exchange. We start with the maximum key length of either
+ * cipher...
*/
- if (kex != &ssh_diffiehellman || hostkey != &ssh_dss) {
- bombout(("internal fault: chaos in SSH 2 transport layer"));
- crReturn(0);
+ {
+ int csbits, scbits;
+
+ csbits = cscipher_tobe->keylen;
+ scbits = sccipher_tobe->keylen;
+ nbits = (csbits > scbits ? csbits : scbits);
}
+ /* The keys only have 160-bit entropy, since they're based on
+ * a SHA-1 hash. So cap the key size at 160 bits. */
+ if (nbits > 160) nbits = 160;
/*
- * Now we begin the fun. Generate and send e for Diffie-Hellman.
+ * If we're doing Diffie-Hellman group exchange, start by
+ * requesting a group.
*/
- e = dh_create_e();
- ssh2_pkt_init(SSH2_MSG_KEXDH_INIT);
+ if (kex == &ssh_diffiehellman_gex) {
+ logevent("Doing Diffie-Hellman group exchange");
+ /*
+ * Work out how big a DH group we will need to allow that
+ * much data.
+ */
+ pbits = 512 << ((nbits-1) / 64);
+ ssh2_pkt_init(SSH2_MSG_KEX_DH_GEX_REQUEST);
+ ssh2_pkt_adduint32(pbits);
+ ssh2_pkt_send();
+
+ crWaitUntil(ispkt);
+ if (pktin.type != SSH2_MSG_KEX_DH_GEX_GROUP) {
+ bombout(("expected key exchange group packet from server"));
+ crReturn(0);
+ }
+ p = ssh2_pkt_getmp();
+ g = ssh2_pkt_getmp();
+ dh_setup_group(p, g);
+ kex_init_value = SSH2_MSG_KEX_DH_GEX_INIT;
+ kex_reply_value = SSH2_MSG_KEX_DH_GEX_REPLY;
+ } else {
+ dh_setup_group1();
+ kex_init_value = SSH2_MSG_KEXDH_INIT;
+ kex_reply_value = SSH2_MSG_KEXDH_REPLY;
+ }
+
+ logevent("Doing Diffie-Hellman key exchange");
+ /*
+ * Now generate and send e for Diffie-Hellman.
+ */
+ e = dh_create_e(nbits*2);
+ ssh2_pkt_init(kex_init_value);
ssh2_pkt_addmp(e);
ssh2_pkt_send();
crWaitUntil(ispkt);
- if (pktin.type != SSH2_MSG_KEXDH_REPLY) {
- bombout(("expected key exchange packet from server"));
+ if (pktin.type != kex_reply_value) {
+ bombout(("expected key exchange reply packet from server"));
crReturn(0);
}
ssh2_pkt_getstring(&hostkeydata, &hostkeylen);
K = dh_find_K(f);
sha_string(&exhash, hostkeydata, hostkeylen);
+ if (kex == &ssh_diffiehellman_gex) {
+ sha_uint32(&exhash, pbits);
+ sha_mpint(&exhash, p);
+ sha_mpint(&exhash, g);
+ }
sha_mpint(&exhash, e);
sha_mpint(&exhash, f);
sha_mpint(&exhash, K);
SHA_Final(&exhash, exchange_hash);
+ dh_cleanup();
+
#if 0
debug(("Exchange hash is:\r\n"));
for (i = 0; i < 20; i++)
fingerprint = hostkey->fingerprint(hkey);
verify_ssh_host_key(savedhost, savedport, hostkey->keytype,
keystr, fingerprint);
- logevent("Host key fingerprint is:");
- logevent(fingerprint);
+ if (first_kex) { /* don't bother logging this in rekeys */
+ logevent("Host key fingerprint is:");
+ logevent(fingerprint);
+ }
sfree(fingerprint);
sfree(keystr);
hostkey->freekey(hkey);
cscomp->compress_init();
sccomp->decompress_init();
/*
- * Set IVs after keys.
+ * Set IVs after keys. Here we use the exchange hash from the
+ * _first_ key exchange.
*/
- ssh2_mkkey(K, exchange_hash, 'C', keyspace); cscipher->setcskey(keyspace);
- ssh2_mkkey(K, exchange_hash, 'D', keyspace); sccipher->setsckey(keyspace);
- ssh2_mkkey(K, exchange_hash, 'A', keyspace); cscipher->setcsiv(keyspace);
- ssh2_mkkey(K, exchange_hash, 'B', keyspace); sccipher->setsciv(keyspace);
- ssh2_mkkey(K, exchange_hash, 'E', keyspace); csmac->setcskey(keyspace);
- ssh2_mkkey(K, exchange_hash, 'F', keyspace); scmac->setsckey(keyspace);
+ if (first_kex)
+ memcpy(ssh2_session_id, exchange_hash, sizeof(exchange_hash));
+ ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'C', keyspace);
+ cscipher->setcskey(keyspace);
+ ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'D', keyspace);
+ sccipher->setsckey(keyspace);
+ ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'A', keyspace);
+ cscipher->setcsiv(keyspace);
+ ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'B', keyspace);
+ sccipher->setsciv(keyspace);
+ ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'E', keyspace);
+ csmac->setcskey(keyspace);
+ ssh2_mkkey(K, exchange_hash, ssh2_session_id, 'F', keyspace);
+ scmac->setsckey(keyspace);
/*
* If this is the first key exchange phase, we must pass the
* transport. If we ever see a KEXINIT, we must go back to the
* start.
*/
- do {
+ while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT)) {
crReturn(1);
- } while (!(ispkt && pktin.type == SSH2_MSG_KEXINIT));
+ }
+ logevent("Server initiated key re-exchange");
goto begin_key_exchange;
crFinish(1);
{
static unsigned long remote_winsize;
static unsigned long remote_maxpkt;
+ static enum {
+ AUTH_INVALID, AUTH_PUBLICKEY_AGENT, AUTH_PUBLICKEY_FILE, AUTH_PASSWORD
+ } method;
+ static enum {
+ AUTH_TYPE_NONE,
+ AUTH_TYPE_PUBLICKEY,
+ AUTH_TYPE_PUBLICKEY_OFFER_LOUD,
+ AUTH_TYPE_PUBLICKEY_OFFER_QUIET,
+ AUTH_TYPE_PASSWORD
+ } type;
+ static int gotit, need_pw, can_pubkey, can_passwd;
+ static int tried_pubkey_config, tried_agent;
+ static int we_are_in;
+ static char username[100];
+ static char pwprompt[200];
+ static char password[100];
crBegin;
}
/*
- * FIXME: currently we support only password authentication.
- * (This places us technically in violation of the SSH2 spec.
- * We must fix this.)
+ * We repeat this whole loop, including the username prompt,
+ * until we manage a successful authentication. If the user
+ * types the wrong _password_, they are sent back to the
+ * beginning to try another username. (If they specify a
+ * username in the config, they are never asked, even if they
+ * do give a wrong password.)
+ *
+ * I think this best serves the needs of
+ *
+ * - the people who have no configuration, no keys, and just
+ * want to try repeated (username,password) pairs until they
+ * type both correctly
+ *
+ * - people who have keys and configuration but occasionally
+ * need to fall back to passwords
+ *
+ * - people with a key held in Pageant, who might not have
+ * logged in to a particular machine before; so they want to
+ * type a username, and then _either_ their key will be
+ * accepted, _or_ they will type a password. If they mistype
+ * the username they will want to be able to get back and
+ * retype it!
*/
- while (1) {
- /*
- * Get a username and a password.
- */
- static char username[100];
- static char password[100];
- static int pos = 0;
+ do {
+ static int pos;
static char c;
+ /*
+ * Get a username.
+ */
+ pos = 0;
if ((flags & FLAG_INTERACTIVE) && !*cfg.username) {
- c_write("login as: ", 10);
- ssh_send_ok = 1;
- while (pos >= 0) {
- 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("\b \b", 3);
- pos--;
- }
- break;
- case 21: case 27:
- while (pos > 0) {
- c_write("\b \b", 3);
- pos--;
- }
- break;
- case 3: case 4:
- random_save_seed();
- exit(0);
- break;
- default:
- if (((c >= ' ' && c <= '~') ||
- ((unsigned char)c >= 160)) && pos < 40) {
- username[pos++] = c;
- c_write(&c, 1);
- }
- break;
- }
- }
- c_write("\r\n", 2);
+ if (ssh_get_line) {
+ if (!ssh_get_line("login as: ",
+ username, sizeof(username), FALSE)) {
+ /*
+ * get_line failed to get a username.
+ * Terminate.
+ */
+ logevent("No username provided. Abandoning session.");
+ ssh_state = SSH_STATE_CLOSED;
+ crReturn(1);
+ }
+ } else {
+ c_write_str("login as: ");
+ ssh_send_ok = 1;
+ while (pos >= 0) {
+ 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:
+ random_save_seed();
+ exit(0);
+ break;
+ default:
+ if (((c >= ' ' && c <= '~') ||
+ ((unsigned char)c >= 160)) && pos < 40) {
+ username[pos++] = c;
+ c_write(&c, 1);
+ }
+ break;
+ }
+ }
+ }
+ c_write_str("\r\n");
username[strcspn(username, "\n\r")] = '\0';
} else {
char stuff[200];
strncpy(username, cfg.username, 99);
username[99] = '\0';
- if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
+ if ((flags & FLAG_VERBOSE) || (flags & FLAG_INTERACTIVE)) {
sprintf(stuff, "Using username \"%s\".\r\n", username);
- c_write(stuff, strlen(stuff));
+ c_write_str(stuff);
}
}
- if (ssh_get_password) {
- char prompt[200];
- sprintf(prompt, "%.90s@%.90s's password: ", username, savedhost);
- if (!ssh_get_password(prompt, password, sizeof(password))) {
- /*
- * get_password failed to get a password (for
- * example because one was supplied on the command
- * line which has already failed to work).
- * Terminate.
- */
- logevent("No more passwords to try");
- ssh_state = SSH_STATE_CLOSED;
- crReturnV;
- }
- } else {
- c_write("password: ", 10);
- ssh_send_ok = 1;
+ /*
+ * Send an authentication request using method "none": (a)
+ * just in case it succeeds, and (b) so that we know what
+ * authentication methods we can usefully try next.
+ */
+ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+ ssh2_pkt_addstring(username);
+ ssh2_pkt_addstring("ssh-connection"); /* service requested */
+ ssh2_pkt_addstring("none"); /* method */
+ ssh2_pkt_send();
+ type = AUTH_TYPE_NONE;
+ gotit = FALSE;
+ we_are_in = FALSE;
+
+ tried_pubkey_config = FALSE;
+ tried_agent = FALSE;
+
+ while (1) {
+ /*
+ * Wait for the result of the last authentication request.
+ */
+ if (!gotit)
+ crWaitUntilV(ispkt);
+ while (pktin.type == SSH2_MSG_USERAUTH_BANNER) {
+ /* FIXME: should support this */
+ crWaitUntilV(ispkt);
+ }
+ if (pktin.type == SSH2_MSG_USERAUTH_SUCCESS) {
+ logevent("Access granted");
+ we_are_in = TRUE;
+ break;
+ }
- pos = 0;
- while (pos >= 0) {
- 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:
- random_save_seed();
- exit(0);
- break;
- default:
- if (((c >= ' ' && c <= '~') ||
- ((unsigned char)c >= 160)) && pos < 40)
- password[pos++] = c;
- break;
- }
- }
- c_write("\r\n", 2);
- }
+ if (pktin.type != SSH2_MSG_USERAUTH_FAILURE) {
+ bombout(("Strange packet received during authentication: type %d",
+ pktin.type));
+ }
- ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
- ssh2_pkt_addstring(username);
- ssh2_pkt_addstring("ssh-connection"); /* service requested */
- ssh2_pkt_addstring("password");
- ssh2_pkt_addbool(FALSE);
- ssh2_pkt_addstring(password);
- ssh2_pkt_send();
+ gotit = FALSE;
+
+ /*
+ * OK, we're now sitting on a USERAUTH_FAILURE message, so
+ * we can look at the string in it and know what we can
+ * helpfully try next.
+ */
+ {
+ char *methods;
+ int methlen;
+ ssh2_pkt_getstring(&methods, &methlen);
+ if (!ssh2_pkt_getbool()) {
+ /*
+ * We have received an unequivocal Access
+ * Denied. This can translate to a variety of
+ * messages:
+ *
+ * - if we'd just tried "none" authentication,
+ * it's not worth printing anything at all
+ *
+ * - if we'd just tried a public key _offer_,
+ * the message should be "Server refused our
+ * key" (or no message at all if the key
+ * came from Pageant)
+ *
+ * - if we'd just tried anything else, the
+ * message really should be "Access denied".
+ *
+ * Additionally, if we'd just tried password
+ * authentication, we should break out of this
+ * whole loop so as to go back to the username
+ * prompt.
+ */
+ if (type == AUTH_TYPE_NONE) {
+ /* do nothing */
+ } else if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD ||
+ type == AUTH_TYPE_PUBLICKEY_OFFER_QUIET) {
+ if (type == AUTH_TYPE_PUBLICKEY_OFFER_LOUD)
+ c_write_str("Server refused our key\r\n");
+ logevent("Server refused public key");
+ } else {
+ c_write_str("Access denied\r\n");
+ logevent("Access denied");
+ if (type == AUTH_TYPE_PASSWORD) {
+ we_are_in = FALSE;
+ break;
+ }
+ }
+ } else {
+ c_write_str("Further authentication required\r\n");
+ logevent("Further authentication required");
+ }
- crWaitUntilV(ispkt);
- if (pktin.type != SSH2_MSG_USERAUTH_SUCCESS) {
- c_write("Access denied\r\n", 15);
- logevent("Authentication refused");
- } else
- break;
- }
+ can_pubkey = in_commasep_string("publickey", methods, methlen);
+ can_passwd = in_commasep_string("password", methods, methlen);
+ }
+
+ method = 0;
+
+ if (!method && can_pubkey && agent_exists && !tried_agent) {
+ /*
+ * Attempt public-key authentication using Pageant.
+ */
+ static unsigned char request[5], *response, *p;
+ static int responselen;
+ static int i, nkeys;
+ static int authed = FALSE;
+ void *r;
+
+ tried_agent = TRUE;
+
+ logevent("Pageant is running. Requesting keys.");
+
+ /* Request the keys held by the agent. */
+ PUT_32BIT(request, 1);
+ request[4] = SSH2_AGENTC_REQUEST_IDENTITIES;
+ agent_query(request, 5, &r, &responselen);
+ response = (unsigned char *)r;
+ if (response) {
+ p = response + 5;
+ nkeys = GET_32BIT(p); p += 4;
+ { char buf[64]; sprintf(buf, "Pageant has %d SSH2 keys", nkeys);
+ logevent(buf); }
+ for (i = 0; i < nkeys; i++) {
+ static char *pkblob, *alg, *commentp;
+ static int pklen, alglen, commentlen;
+ static int siglen, retlen, len;
+ static char *q, *agentreq, *ret;
+
+ { char buf[64]; sprintf(buf, "Trying Pageant key #%d", i);
+ logevent(buf); }
+ pklen = GET_32BIT(p); p += 4;
+ pkblob = p; p += pklen;
+ alglen = GET_32BIT(pkblob);
+ alg = pkblob + 4;
+ commentlen = GET_32BIT(p); p += 4;
+ commentp = p; p += commentlen;
+ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+ ssh2_pkt_addstring(username);
+ ssh2_pkt_addstring("ssh-connection");/* service requested */
+ ssh2_pkt_addstring("publickey");/* method */
+ ssh2_pkt_addbool(FALSE); /* no signature included */
+ ssh2_pkt_addstring_start();
+ ssh2_pkt_addstring_data(alg, alglen);
+ ssh2_pkt_addstring_start();
+ ssh2_pkt_addstring_data(pkblob, pklen);
+ ssh2_pkt_send();
+
+ crWaitUntilV(ispkt);
+ if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
+ logevent("Key refused");
+ continue;
+ }
+
+ c_write_str("Authenticating with public key \"");
+ c_write(commentp, commentlen);
+ c_write_str("\" from agent\r\n");
+
+ /*
+ * Server is willing to accept the key.
+ * Construct a SIGN_REQUEST.
+ */
+ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+ ssh2_pkt_addstring(username);
+ ssh2_pkt_addstring("ssh-connection"); /* service requested */
+ ssh2_pkt_addstring("publickey"); /* method */
+ ssh2_pkt_addbool(TRUE);
+ ssh2_pkt_addstring_start();
+ ssh2_pkt_addstring_data(alg, alglen);
+ ssh2_pkt_addstring_start();
+ ssh2_pkt_addstring_data(pkblob, pklen);
+
+ siglen = pktout.length - 5 + 4 + 20;
+ len = 1; /* message type */
+ len += 4 + pklen; /* key blob */
+ len += 4 + siglen; /* data to sign */
+ len += 4; /* flags */
+ agentreq = smalloc(4 + len);
+ PUT_32BIT(agentreq, len);
+ q = agentreq + 4;
+ *q++ = SSH2_AGENTC_SIGN_REQUEST;
+ PUT_32BIT(q, pklen); q += 4;
+ memcpy(q, pkblob, pklen); q += pklen;
+ PUT_32BIT(q, siglen); q += 4;
+ /* Now the data to be signed... */
+ PUT_32BIT(q, 20); q += 4;
+ memcpy(q, ssh2_session_id, 20); q += 20;
+ memcpy(q, pktout.data+5, pktout.length-5);
+ q += pktout.length-5;
+ /* And finally the (zero) flags word. */
+ PUT_32BIT(q, 0);
+ agent_query(agentreq, len+4, &ret, &retlen);
+ sfree(agentreq);
+ 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_pkt_send();
+ authed = TRUE;
+ break;
+ } else {
+ logevent("Pageant failed to answer challenge");
+ sfree(ret);
+ }
+ }
+ }
+ if (authed)
+ continue;
+ }
+ }
+
+ if (!method && can_pubkey && *cfg.keyfile && !tried_pubkey_config) {
+ unsigned char *pub_blob;
+ char *algorithm, *comment;
+ int pub_blob_len;
+
+ tried_pubkey_config = TRUE;
+
+ /*
+ * Try the public key supplied in the configuration.
+ *
+ * First, offer the public blob to see if the server is
+ * willing to accept it.
+ */
+ pub_blob = ssh2_userkey_loadpub(cfg.keyfile, &algorithm,
+ &pub_blob_len);
+ if (pub_blob) {
+ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+ ssh2_pkt_addstring(username);
+ ssh2_pkt_addstring("ssh-connection"); /* service requested */
+ ssh2_pkt_addstring("publickey");/* method */
+ ssh2_pkt_addbool(FALSE); /* no signature included */
+ ssh2_pkt_addstring(algorithm);
+ ssh2_pkt_addstring_start();
+ ssh2_pkt_addstring_data(pub_blob, pub_blob_len);
+ ssh2_pkt_send();
+ logevent("Offered public key"); /* FIXME */
+
+ crWaitUntilV(ispkt);
+ if (pktin.type != SSH2_MSG_USERAUTH_PK_OK) {
+ gotit = TRUE;
+ type = AUTH_TYPE_PUBLICKEY_OFFER_LOUD;
+ continue; /* key refused; give up on it */
+ }
+
+ logevent("Offer of public key accepted");
+ /*
+ * Actually attempt a serious authentication using
+ * the key.
+ */
+ if (ssh2_userkey_encrypted(cfg.keyfile, &comment)) {
+ sprintf(pwprompt, "Passphrase for key \"%.100s\": ", comment);
+ need_pw = TRUE;
+ } else {
+ need_pw = FALSE;
+ }
+ c_write_str("Authenticating with public key \"");
+ c_write_str(comment);
+ c_write_str("\"\r\n");
+ method = AUTH_PUBLICKEY_FILE;
+ }
+ }
+
+ if (!method && can_passwd) {
+ method = AUTH_PASSWORD;
+ sprintf(pwprompt, "%.90s@%.90s's password: ", username, savedhost);
+ need_pw = TRUE;
+ }
+
+ if (need_pw) {
+ if (ssh_get_line) {
+ if (!ssh_get_line(pwprompt, password,
+ sizeof(password), TRUE)) {
+ /*
+ * get_line failed to get a password (for
+ * example because one was supplied on the
+ * command line which has already failed to
+ * work). Terminate.
+ */
+ logevent("No more passwords to try");
+ ssh_state = SSH_STATE_CLOSED;
+ crReturnV;
+ }
+ } else {
+ static int pos = 0;
+ static char c;
+
+ c_write_str(pwprompt);
+ ssh_send_ok = 1;
+
+ pos = 0;
+ while (pos >= 0) {
+ 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:
+ random_save_seed();
+ exit(0);
+ break;
+ default:
+ if (((c >= ' ' && c <= '~') ||
+ ((unsigned char)c >= 160)) && pos < 40)
+ password[pos++] = c;
+ break;
+ }
+ }
+ c_write_str("\r\n");
+ }
+ }
+
+ if (method == AUTH_PUBLICKEY_FILE) {
+ /*
+ * We have our passphrase. Now try the actual authentication.
+ */
+ struct ssh2_userkey *key;
+
+ key = ssh2_load_userkey(cfg.keyfile, password);
+ if (key == SSH2_WRONG_PASSPHRASE || key == NULL) {
+ if (key == SSH2_WRONG_PASSPHRASE) {
+ c_write_str("Wrong passphrase\r\n");
+ tried_pubkey_config = FALSE;
+ } else {
+ c_write_str("Unable to load private key\r\n");
+ tried_pubkey_config = TRUE;
+ }
+ /* Send a spurious AUTH_NONE to return to the top. */
+ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+ ssh2_pkt_addstring(username);
+ ssh2_pkt_addstring("ssh-connection"); /* service requested */
+ ssh2_pkt_addstring("none"); /* method */
+ ssh2_pkt_send();
+ type = AUTH_TYPE_NONE;
+ } else {
+ unsigned char *blob, *sigdata;
+ int blob_len, sigdata_len;
+
+ /*
+ * We have loaded the private key and the server
+ * has announced that it's willing to accept it.
+ * Hallelujah. Generate a signature and send it.
+ */
+ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+ ssh2_pkt_addstring(username);
+ ssh2_pkt_addstring("ssh-connection"); /* service requested */
+ ssh2_pkt_addstring("publickey"); /* method */
+ ssh2_pkt_addbool(TRUE);
+ ssh2_pkt_addstring(key->alg->name);
+ blob = key->alg->public_blob(key->data, &blob_len);
+ ssh2_pkt_addstring_start();
+ ssh2_pkt_addstring_data(blob, blob_len);
+ sfree(blob);
+
+ /*
+ * The data to be signed is:
+ *
+ * string session-id
+ *
+ * followed by everything so far placed in the
+ * outgoing packet.
+ */
+ sigdata_len = pktout.length - 5 + 4 + 20;
+ sigdata = smalloc(sigdata_len);
+ PUT_32BIT(sigdata, 20);
+ 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);
+ sfree(sigdata);
+
+ ssh2_pkt_send();
+ type = AUTH_TYPE_PUBLICKEY;
+ }
+ } else if (method == AUTH_PASSWORD) {
+ /*
+ * We send the password packet lumped tightly together with
+ * an SSH_MSG_IGNORE packet. The IGNORE packet contains a
+ * string long enough to make the total length of the two
+ * packets constant. This should ensure that a passive
+ * listener doing traffic analyis can't work out the length
+ * of the password.
+ *
+ * For this to work, we need an assumption about the
+ * maximum length of the password packet. I think 256 is
+ * pretty conservative. Anyone using a password longer than
+ * that probably doesn't have much to worry about from
+ * people who find out how long their password is!
+ */
+ ssh2_pkt_init(SSH2_MSG_USERAUTH_REQUEST);
+ ssh2_pkt_addstring(username);
+ ssh2_pkt_addstring("ssh-connection"); /* service requested */
+ ssh2_pkt_addstring("password");
+ ssh2_pkt_addbool(FALSE);
+ ssh2_pkt_addstring(password);
+ ssh2_pkt_defer();
+ /*
+ * We'll include a string that's an exact multiple of the
+ * cipher block size. If the cipher is NULL for some
+ * reason, we don't do this trick at all because we gain
+ * nothing by it.
+ */
+ if (cscipher) {
+ int stringlen, i;
+
+ stringlen = (256 - deferred_len);
+ stringlen += cscipher->blksize - 1;
+ stringlen -= (stringlen % cscipher->blksize);
+ if (cscomp) {
+ /*
+ * Temporarily disable actual compression,
+ * so we can guarantee to get this string
+ * exactly the length we want it. The
+ * compression-disabling routine should
+ * return an integer indicating how many
+ * bytes we should adjust our string length
+ * by.
+ */
+ stringlen -= cscomp->disable_compression();
+ }
+ ssh2_pkt_init(SSH2_MSG_IGNORE);
+ ssh2_pkt_addstring_start();
+ for (i = 0; i < stringlen; i++) {
+ char c = (char)random_byte();
+ ssh2_pkt_addstring_data(&c, 1);
+ }
+ ssh2_pkt_defer();
+ }
+ ssh_pkt_defersend();
+ logevent("Sent password");
+ type = AUTH_TYPE_PASSWORD;
+ } else {
+ c_write_str("No supported authentication methods left to try!\r\n");
+ logevent("No supported authentications offered. Disconnecting");
+ ssh2_pkt_init(SSH2_MSG_DISCONNECT);
+ ssh2_pkt_adduint32(SSH2_DISCONNECT_BY_APPLICATION);
+ ssh2_pkt_addstring("No supported authentication methods available");
+ ssh2_pkt_addstring("en"); /* language tag */
+ ssh2_pkt_send();
+ ssh_state = SSH_STATE_CLOSED;
+ crReturnV;
+ }
+ }
+ } while (!we_are_in);
/*
* Now we're authenticated for the connection protocol. The
}
/*
+ * Potentially enable agent forwarding.
+ */
+ if (cfg.agentfwd && agent_exists()) {
+ char proto[20], data[64];
+ logevent("Requesting OpenSSH-style agent forwarding");
+ x11_invent_auth(proto, sizeof(proto), data, sizeof(data));
+ ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
+ ssh2_pkt_adduint32(mainchan->remoteid);
+ ssh2_pkt_addstring("auth-agent-req@openssh.com");
+ ssh2_pkt_addbool(1); /* want reply */
+ ssh2_pkt_send();
+
+ do {
+ crWaitUntilV(ispkt);
+ if (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST) {
+ unsigned i = ssh2_pkt_getuint32();
+ struct ssh_channel *c;
+ c = find234(ssh_channels, &i, ssh_channelfind);
+ if (!c)
+ continue; /* nonexistent channel */
+ c->v2.remwindow += ssh2_pkt_getuint32();
+ }
+ } while (pktin.type == SSH2_MSG_CHANNEL_WINDOW_ADJUST);
+
+ if (pktin.type != SSH2_MSG_CHANNEL_SUCCESS) {
+ if (pktin.type != SSH2_MSG_CHANNEL_FAILURE) {
+ bombout(("Server got confused by agent forwarding request"));
+ crReturnV;
+ }
+ logevent("Agent forwarding refused");
+ } else {
+ logevent("Agent forwarding enabled");
+ ssh_agentfwd_enabled = TRUE;
+ }
+ }
+
+ /*
* Now allocate a pty for the session.
*/
if (!cfg.nopty) {
bombout(("Server got confused by pty request"));
crReturnV;
}
- c_write("Server refused to allocate pty\r\n", 32);
+ c_write_str("Server refused to allocate pty\r\n");
ssh_editing = ssh_echoing = 1;
} else {
logevent("Allocated pty");
*/
ssh2_pkt_init(SSH2_MSG_CHANNEL_REQUEST);
ssh2_pkt_adduint32(mainchan->remoteid); /* recipient channel */
- if (*cfg.remote_cmd) {
+ if (cfg.ssh_subsys) {
+ ssh2_pkt_addstring("subsystem");
+ ssh2_pkt_addbool(1); /* want reply */
+ ssh2_pkt_addstring(cfg.remote_cmd);
+ } else if (*cfg.remote_cmd) {
ssh2_pkt_addstring("exec");
ssh2_pkt_addbool(1); /* want reply */
ssh2_pkt_addstring(cfg.remote_cmd);
case CHAN_X11:
x11_send(c->u.x11.s, data, length);
break;
+ case CHAN_AGENT:
+ while (length > 0) {
+ if (c->u.a.lensofar < 4) {
+ int l = min(4 - c->u.a.lensofar, length);
+ memcpy(c->u.a.msglen + c->u.a.lensofar, data, l);
+ data += l; length -= l; c->u.a.lensofar += l;
+ }
+ if (c->u.a.lensofar == 4) {
+ c->u.a.totallen = 4 + GET_32BIT(c->u.a.msglen);
+ c->u.a.message = smalloc(c->u.a.totallen);
+ memcpy(c->u.a.message, c->u.a.msglen, 4);
+ }
+ if (c->u.a.lensofar >= 4 && length > 0) {
+ int l = min(c->u.a.totallen - c->u.a.lensofar,
+ length);
+ memcpy(c->u.a.message + c->u.a.lensofar, data, l);
+ data += l; length -= l; c->u.a.lensofar += l;
+ }
+ if (c->u.a.lensofar == c->u.a.totallen) {
+ void *reply, *sentreply;
+ int replylen;
+ agent_query(c->u.a.message, c->u.a.totallen,
+ &reply, &replylen);
+ if (reply)
+ sentreply = reply;
+ else {
+ /* Fake SSH_AGENT_FAILURE. */
+ sentreply = "\0\0\0\1\5";
+ replylen = 5;
+ }
+ ssh2_add_channel_data(c, sentreply, replylen);
+ try_send = TRUE;
+ if (reply)
+ sfree(reply);
+ sfree(c->u.a.message);
+ c->u.a.lensofar = 0;
+ }
+ }
+ break;
}
/*
* Enlarge the window again at the remote
*/
x11_close(c->u.x11.s);
sshfwd_close(c);
- }
+ } else if (c->type == CHAN_AGENT) {
+ sshfwd_close(c);
+ }
} else if (pktin.type == SSH2_MSG_CHANNEL_CLOSE) {
unsigned i = ssh2_pkt_getuint32();
struct ssh_channel *c;
break; /* nothing to see here, move along */
case CHAN_X11:
break;
+ case CHAN_AGENT:
+ break;
}
del234(ssh_channels, c);
sfree(c->v2.outbuffer);
} else {
c->type = CHAN_X11;
}
+ } else if (typelen == 22 &&
+ !memcmp(type, "auth-agent@openssh.com", 3)) {
+ if (!ssh_agentfwd_enabled)
+ error = "Agent forwarding is not enabled";
+ else {
+ c->type = CHAN_AGENT; /* identify channel type */
+ c->u.a.lensofar = 0;
+ }
} else {
error = "Unsupported channel type requested";
}
projects / u / mdw / putty / blobdiff