#include "ssh.h"
+#define SSH_MSG_DISCONNECT 1
+#define SSH_SMSG_PUBLIC_KEY 2
+#define SSH_CMSG_SESSION_KEY 3
+#define SSH_CMSG_USER 4
+#define SSH_CMSG_AUTH_PASSWORD 9
+#define SSH_CMSG_REQUEST_PTY 10
+#define SSH_CMSG_EXEC_SHELL 12
+#define SSH_CMSG_STDIN_DATA 16
+#define SSH_SMSG_STDOUT_DATA 17
+#define SSH_SMSG_STDERR_DATA 18
+#define SSH_SMSG_SUCCESS 14
+#define SSH_SMSG_FAILURE 15
+#define SSH_SMSG_EXITSTATUS 20
+#define SSH_MSG_IGNORE 32
+#define SSH_CMSG_EXIT_CONFIRMATION 33
+#define SSH_MSG_DEBUG 36
+#define SSH_CMSG_AUTH_TIS 39
+#define SSH_SMSG_AUTH_TIS_CHALLENGE 40
+#define SSH_CMSG_AUTH_TIS_RESPONSE 41
+
+#define SSH_AUTH_TIS 5
+
/* Coroutine mechanics for the sillier bits of the code */
#define crBegin1 static int crLine = 0;
#define crBegin2 switch(crLine) { case 0:;
static enum {
SSH_STATE_BEFORE_SIZE,
SSH_STATE_INTERMED,
- SSH_STATE_SESSION
+ SSH_STATE_SESSION,
+ SSH_STATE_CLOSED
} ssh_state = SSH_STATE_BEFORE_SIZE;
static int size_needed = FALSE;
static void c_write (char *buf, int len) {
while (len--) {
int new_head = (inbuf_head + 1) & INBUF_MASK;
- int c = (unsigned char) *buf;
if (new_head != inbuf_reap) {
inbuf[inbuf_head] = *buf++;
inbuf_head = new_head;
static void ssh_gotdata(unsigned char *data, int datalen) {
static long len, biglen, to_read;
- static unsigned char c, *p;
+ static unsigned char *p;
static int i, pad;
- static char padding[8];
- static unsigned char word[4];
crBegin;
while (1) {
pktin.type = pktin.data[pad];
pktin.body = pktin.data+pad+1;
- if (pktin.type == 36) { /* SSH_MSG_DEBUG */
+ if (pktin.type == SSH_MSG_DEBUG) {
/* FIXME: log it */
+ } else if (pktin.type == SSH_MSG_IGNORE) {
+ /* do nothing */;
} else
ssh_protocol(NULL, 0, 1);
}
s_write(pktout.data, biglen+4);
}
+static int ssh_versioncmp(char *a, char *b) {
+ char *ae, *be;
+ unsigned long av, bv;
+
+ av = strtoul(a, &ae, 10);
+ bv = strtoul(b, &be, 10);
+ if (av != bv) return (av < bv ? -1 : +1);
+ if (*ae == '.') ae++;
+ if (*be == '.') be++;
+ av = strtoul(ae, &ae, 10);
+ bv = strtoul(be, &be, 10);
+ if (av != bv) return (av < bv ? -1 : +1);
+ return 0;
+}
+
static int do_ssh_init(void) {
- char c;
+ char c, *vsp;
char version[10];
- char vstring[40];
+ char vstring[80];
+ char vlog[sizeof(vstring)+20];
int i;
#ifdef FWHACK
if (s_read(&c,1) != 1 || c != 'S') return 0;
if (s_read(&c,1) != 1 || c != 'H') return 0;
#endif
+ strcpy(vstring, "SSH-");
+ vsp = vstring+4;
if (s_read(&c,1) != 1 || c != '-') return 0;
i = 0;
while (1) {
if (s_read(&c,1) != 1)
return 0;
+ if (vsp < vstring+sizeof(vstring)-1)
+ *vsp++ = c;
if (i >= 0) {
if (c == '-') {
version[i] = '\0';
break;
}
- sprintf(vstring, "SSH-%s-7.7.7\n",
- (strcmp(version, "1.5") <= 0 ? version : "1.5"));
+ *vsp = 0;
+ sprintf(vlog, "Server version: %s", vstring);
+ vlog[strcspn(vlog, "\r\n")] = '\0';
+ logevent(vlog);
+
+ sprintf(vstring, "SSH-%s-PuTTY\n",
+ (ssh_versioncmp(version, "1.5") <= 0 ? version : "1.5"));
+ sprintf(vlog, "We claim version: %s", vstring);
+ vlog[strcspn(vlog, "\r\n")] = '\0';
+ logevent(vlog);
s_write(vstring, strlen(vstring));
return 1;
}
unsigned char cookie[8];
struct RSAKey servkey, hostkey;
struct MD5Context md5c;
+ static unsigned long supported_ciphers_mask, supported_auths_mask;
+ int cipher_type;
extern struct ssh_cipher ssh_3des;
+ extern struct ssh_cipher ssh_des;
+ extern struct ssh_cipher ssh_blowfish;
crBegin;
while (!ispkt)
crReturnV;
- if (pktin.type != 2)
+ if (pktin.type != SSH_SMSG_PUBLIC_KEY)
fatalbox("Public key packet not received");
- memcpy(cookie, pktin.body, 8);
+ logevent("Received public keys");
- MD5Init(&md5c);
+ memcpy(cookie, pktin.body, 8);
i = makekey(pktin.body+8, &servkey, &keystr1);
j = makekey(pktin.body+8+i, &hostkey, &keystr2);
+ /*
+ * Hash the host key and print the hash in the log box. Just as
+ * a last resort in case the registry's host key checking is
+ * compromised, we'll allow the user some ability to verify
+ * host keys by eye.
+ */
+ MD5Init(&md5c);
+ MD5Update(&md5c, keystr2, hostkey.bytes);
+ MD5Final(session_id, &md5c);
+ {
+ char logmsg[80];
+ int i;
+ logevent("Host key MD5 is:");
+ strcpy(logmsg, " ");
+ for (i = 0; i < 16; i++)
+ sprintf(logmsg+strlen(logmsg), "%02x", session_id[i]);
+ logevent(logmsg);
+ }
+
+ supported_ciphers_mask = ((pktin.body[12+i+j] << 24) |
+ (pktin.body[13+i+j] << 16) |
+ (pktin.body[14+i+j] << 8) |
+ (pktin.body[15+i+j]));
+
+ supported_auths_mask = ((pktin.body[16+i+j] << 24) |
+ (pktin.body[17+i+j] << 16) |
+ (pktin.body[18+i+j] << 8) |
+ (pktin.body[19+i+j]));
+
+ MD5Init(&md5c);
+
MD5Update(&md5c, keystr2, hostkey.bytes);
MD5Update(&md5c, keystr1, servkey.bytes);
MD5Update(&md5c, pktin.body, 8);
rsaencrypt(rsabuf, hostkey.bytes, &servkey);
}
- s_wrpkt_start(3, len+15);
- pktout.body[0] = 3; /* SSH_CIPHER_3DES */
+ logevent("Encrypted session key");
+
+ cipher_type = cfg.cipher == CIPHER_BLOWFISH ? SSH_CIPHER_BLOWFISH :
+ cfg.cipher == CIPHER_DES ? SSH_CIPHER_DES :
+ SSH_CIPHER_3DES;
+ if ((supported_ciphers_mask & (1 << cipher_type)) == 0) {
+ c_write("Selected cipher not supported, falling back to 3DES\r\n", 53);
+ cipher_type = SSH_CIPHER_3DES;
+ }
+ switch (cipher_type) {
+ case SSH_CIPHER_3DES: logevent("Using 3DES encryption"); break;
+ case SSH_CIPHER_DES: logevent("Using single-DES encryption"); break;
+ case SSH_CIPHER_BLOWFISH: logevent("Using Blowfish encryption"); break;
+ }
+
+ s_wrpkt_start(SSH_CMSG_SESSION_KEY, len+15);
+ pktout.body[0] = cipher_type;
memcpy(pktout.body+1, cookie, 8);
pktout.body[9] = (len*8) >> 8;
pktout.body[10] = (len*8) & 0xFF;
pktout.body[len+11] = pktout.body[len+12] = 0; /* protocol flags */
pktout.body[len+13] = pktout.body[len+14] = 0;
s_wrpkt();
+ logevent("Trying to enable encryption...");
free(rsabuf);
- cipher = &ssh_3des;
+ cipher = cipher_type == SSH_CIPHER_BLOWFISH ? &ssh_blowfish :
+ cipher_type == SSH_CIPHER_DES ? &ssh_des :
+ &ssh_3des;
cipher->sesskey(session_key);
do { crReturnV; } while (!ispkt);
- if (pktin.type != 14)
+ if (pktin.type != SSH_SMSG_SUCCESS)
fatalbox("Encryption not successfully enabled");
+ logevent("Successfully started encryption");
+
fflush(stdout);
{
static char username[100];
sprintf(stuff, "Sent username \"%s\".\r\n", username);
c_write(stuff, strlen(stuff));
}
- s_wrpkt_start(4, 4+strlen(username));
+ s_wrpkt_start(SSH_CMSG_USER, 4+strlen(username));
+ {
+ char userlog[20+sizeof(username)];
+ sprintf(userlog, "Sent username \"%s\"", username);
+ logevent(userlog);
+ }
pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
pktout.body[3] = strlen(username);
memcpy(pktout.body+4, username, strlen(username));
do { crReturnV; } while (!ispkt);
- while (pktin.type == 15) {
+ while (pktin.type == SSH_SMSG_FAILURE) {
static char password[100];
static int pos;
static char c;
- c_write("password: ", 10);
+ static int pwpkt_type;
+
+ /*
+ * Show password prompt, having first obtained it via a TIS
+ * exchange if we're doing TIS authentication.
+ */
+ pwpkt_type = SSH_CMSG_AUTH_PASSWORD;
+ if (pktin.type == SSH_SMSG_FAILURE &&
+ cfg.try_tis_auth &&
+ (supported_auths_mask & (1<<SSH_AUTH_TIS))) {
+ pwpkt_type = SSH_CMSG_AUTH_TIS_RESPONSE;
+ logevent("Requested TIS authentication");
+ s_wrpkt_start(SSH_CMSG_AUTH_TIS, 0);
+ s_wrpkt();
+ do { crReturnV; } while (!ispkt);
+ if (pktin.type != SSH_SMSG_AUTH_TIS_CHALLENGE) {
+ logevent("TIS authentication declined");
+ c_write("TIS authentication refused.\r\n", 29);
+ } else {
+ int challengelen = ((pktin.body[0] << 24) |
+ (pktin.body[1] << 16) |
+ (pktin.body[2] << 8) |
+ (pktin.body[3]));
+ logevent("Received TIS challenge");
+ c_write(pktin.body+4, challengelen);
+ }
+ }
+ if (pwpkt_type == SSH_CMSG_AUTH_PASSWORD)
+ c_write("password: ", 10);
+
pos = 0;
while (pos >= 0) {
do { crReturnV; } while (ispkt);
}
}
c_write("\r\n", 2);
- s_wrpkt_start(9, 4+strlen(password));
+ s_wrpkt_start(pwpkt_type, 4+strlen(password));
pktout.body[0] = pktout.body[1] = pktout.body[2] = 0;
pktout.body[3] = strlen(password);
memcpy(pktout.body+4, password, strlen(password));
s_wrpkt();
+ logevent("Sent password");
memset(password, 0, strlen(password));
do { crReturnV; } while (!ispkt);
if (pktin.type == 15) {
c_write("Access denied\r\n", 15);
+ logevent("Authentication refused");
} else if (pktin.type != 14) {
fatalbox("Strange packet received, type %d", pktin.type);
}
}
+ logevent("Authentication successful");
+
if (!cfg.nopty) {
i = strlen(cfg.termtype);
- s_wrpkt_start(10, i+5*4+1);
+ s_wrpkt_start(SSH_CMSG_REQUEST_PTY, i+5*4+1);
pktout.body[0] = (i >> 24) & 0xFF;
pktout.body[1] = (i >> 16) & 0xFF;
pktout.body[2] = (i >> 8) & 0xFF;
s_wrpkt();
ssh_state = SSH_STATE_INTERMED;
do { crReturnV; } while (!ispkt);
- if (pktin.type != 14 && pktin.type != 15) {
+ if (pktin.type != SSH_SMSG_SUCCESS && pktin.type != SSH_SMSG_FAILURE) {
fatalbox("Protocol confusion");
- } else if (pktin.type == 15) {
+ } else if (pktin.type == SSH_SMSG_FAILURE) {
c_write("Server refused to allocate pty\r\n", 32);
}
+ logevent("Allocated pty");
}
- s_wrpkt_start(12, 0);
+ s_wrpkt_start(SSH_CMSG_EXEC_SHELL, 0);
s_wrpkt();
+ logevent("Started session");
ssh_state = SSH_STATE_SESSION;
if (size_needed)
while (1) {
crReturnV;
if (ispkt) {
- if (pktin.type == 17 || pktin.type == 18) {
+ if (pktin.type == SSH_SMSG_STDOUT_DATA ||
+ pktin.type == SSH_SMSG_STDERR_DATA) {
long len = 0;
for (i = 0; i < 4; i++)
len = (len << 8) + pktin.body[i];
c_write(pktin.body+4, len);
- } else if (pktin.type == 1) {
- /* SSH_MSG_DISCONNECT: do nothing */
- } else if (pktin.type == 14) {
- /* SSH_MSG_SUCCESS: may be from EXEC_SHELL on some servers */
- } else if (pktin.type == 15) {
- /* SSH_MSG_FAILURE: may be from EXEC_SHELL on some servers
+ } else if (pktin.type == SSH_MSG_DISCONNECT) {
+ ssh_state = SSH_STATE_CLOSED;
+ logevent("Received disconnect request");
+ } else if (pktin.type == SSH_SMSG_SUCCESS) {
+ /* may be from EXEC_SHELL on some servers */
+ } else if (pktin.type == SSH_SMSG_FAILURE) {
+ /* may be from EXEC_SHELL on some servers
* if no pty is available or in other odd cases. Ignore */
- } else if (pktin.type == 20) {
- /* EXITSTATUS */
- s_wrpkt_start(33, 0);
+ } else if (pktin.type == SSH_SMSG_EXITSTATUS) {
+ s_wrpkt_start(SSH_CMSG_EXIT_CONFIRMATION, 0);
s_wrpkt();
} else {
fatalbox("Strange packet received: type %d", pktin.type);
}
} else {
- s_wrpkt_start(16, 4+inlen);
+ s_wrpkt_start(SSH_CMSG_STDIN_DATA, 4+inlen);
pktout.body[0] = (inlen >> 24) & 0xFF;
pktout.body[1] = (inlen >> 16) & 0xFF;
pktout.body[2] = (inlen >> 8) & 0xFF;
int ret;
char buf[256];
- if (s == INVALID_SOCKET) /* how the hell did we get here?! */
- return -5000;
+ /*
+ * Because reading less than the whole of the available pending
+ * data can generate an FD_READ event, we need to allow for the
+ * possibility that FD_READ may arrive with FD_CLOSE already in
+ * the queue; so it's possible that we can get here even with s
+ * invalid. If so, we return 1 and don't worry about it.
+ */
+ if (s == INVALID_SOCKET)
+ return 1;
if (WSAGETSELECTERROR(lParam) != 0)
return -WSAGETSELECTERROR(lParam);
switch (WSAGETSELECTEVENT(lParam)) {
case FD_READ:
+ case FD_CLOSE:
ret = recv(s, buf, sizeof(buf), 0);
if (ret < 0 && WSAGetLastError() == WSAEWOULDBLOCK)
return 1;
return -10000-WSAGetLastError();
if (ret == 0) {
s = INVALID_SOCKET;
- return 0; /* can't happen, in theory */
+ return 0;
}
ssh_gotdata (buf, ret);
return 1;
- case FD_CLOSE:
- s = INVALID_SOCKET;
- return 0;
}
return 1; /* shouldn't happen, but WTF */
}
static void ssh_size(void) {
switch (ssh_state) {
case SSH_STATE_BEFORE_SIZE:
+ case SSH_STATE_CLOSED:
break; /* do nothing */
case SSH_STATE_INTERMED:
size_needed = TRUE; /* buffer for later */
projects / u / mdw / putty / blobdiff