1 files changed, 63 insertions, 215 deletions

diff --git a/sshconnect.c b/sshconnect.c
index 6d819279e..fdcdcd855 100644
--- a/sshconnect.c
+++ b/sshconnect.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshconnect.c,v 1.305 2018/09/20 03:30:44 djm Exp $ */
+/* $OpenBSD: sshconnect.c,v 1.314 2019/02/27 19:37:01 markus Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -68,9 +68,8 @@
 #include "authfile.h"
 #include "ssherr.h"
 #include "authfd.h"
+#include "kex.h"
 
-char *client_version_string = NULL;
-char *server_version_string = NULL;
 struct sshkey *previous_host_key = NULL;
 
 static int matching_host_key_dns = 0;
@@ -78,6 +77,7 @@ static int matching_host_key_dns = 0;
 static pid_t proxy_command_pid = 0;
 
 /* import */
+extern int debug_flag;
 extern Options options;
 extern char *__progname;
 
@@ -99,6 +99,24 @@ expand_proxy_command(const char *proxy_command, const char *user,
         return ret;
 }
 
+static void
+stderr_null(void)
+{
+        int devnull;
+
+        if ((devnull = open(_PATH_DEVNULL, O_WRONLY)) == -1) {
+                error("Can't open %s for stderr redirection: %s",
+                    _PATH_DEVNULL, strerror(errno));
+                return;
+        }
+        if (devnull == STDERR_FILENO)
+                return;
+        if (dup2(devnull, STDERR_FILENO) == -1)
+                error("Cannot redirect stderr to %s", _PATH_DEVNULL);
+        if (devnull > STDERR_FILENO)
+                close(devnull);
+}
+
 /*
  * Connect to the given ssh server using a proxy command that passes a
  * a connected fd back to us.
@@ -141,9 +159,13 @@ ssh_proxy_fdpass_connect(struct ssh *ssh, const char *host, u_short port,
                         close(sp[0]);
 
                 /*
-                 * Stderr is left as it is so that error messages get
-                 * printed on the user's terminal.
+                 * Stderr is left for non-ControlPersist connections is so
+                 * error messages may be printed on the user's terminal.
                  */
+                if (!debug_flag && options.control_path != NULL &&
+                    options.control_persist)
+                        stderr_null();
+
                 argv[0] = shell;
                 argv[1] = "-c";
                 argv[2] = command_string;
@@ -219,8 +241,14 @@ ssh_proxy_connect(struct ssh *ssh, const char *host, u_short port,
                 /* Cannot be 1 because pin allocated two descriptors. */
                 close(pout[1]);
 
-                /* Stderr is left as it is so that error messages get
-                   printed on the user's terminal. */
+                /*
+                 * Stderr is left for non-ControlPersist connections is so
+                 * error messages may be printed on the user's terminal.
+                 */
+                if (!debug_flag && options.control_path != NULL &&
+                    options.control_persist)
+                        stderr_null();
+
                 argv[0] = shell;
                 argv[1] = "-c";
                 argv[2] = command_string;
@@ -369,10 +397,6 @@ ssh_create_socket(struct addrinfo *ai)
                         error("getaddrinfo: no addrs");
                         goto fail;
                 }
-                if (res->ai_addrlen > sizeof(bindaddr)) {
-                        error("%s: addr doesn't fit", __func__);
-                        goto fail;
-                }
                 memcpy(&bindaddr, res->ai_addr, res->ai_addrlen);
                 bindaddrlen = res->ai_addrlen;
         } else if (options.bind_interface != NULL) {
@@ -420,73 +444,6 @@ fail:
 }
 
 /*
- * Wait up to *timeoutp milliseconds for fd to be readable. Updates
- * *timeoutp with time remaining.
- * Returns 0 if fd ready or -1 on timeout or error (see errno).
- */
-static int
-waitrfd(int fd, int *timeoutp)
-{
-        struct pollfd pfd;
-        struct timeval t_start;
-        int oerrno, r;
-
-        monotime_tv(&t_start);
-        pfd.fd = fd;
-        pfd.events = POLLIN;
-        for (; *timeoutp >= 0;) {
-                r = poll(&pfd, 1, *timeoutp);
-                oerrno = errno;
-                ms_subtract_diff(&t_start, timeoutp);
-                errno = oerrno;
-                if (r > 0)
-                        return 0;
-                else if (r == -1 && errno != EAGAIN)
-                        return -1;
-                else if (r == 0)
-                        break;
-        }
-        /* timeout */
-        errno = ETIMEDOUT;
-        return -1;
-}
-
-static int
-timeout_connect(int sockfd, const struct sockaddr *serv_addr,
-    socklen_t addrlen, int *timeoutp)
-{
-        int optval = 0;
-        socklen_t optlen = sizeof(optval);
-
-        /* No timeout: just do a blocking connect() */
-        if (*timeoutp <= 0)
-                return connect(sockfd, serv_addr, addrlen);
-
-        set_nonblock(sockfd);
-        if (connect(sockfd, serv_addr, addrlen) == 0) {
-                /* Succeeded already? */
-                unset_nonblock(sockfd);
-                return 0;
-        } else if (errno != EINPROGRESS)
-                return -1;
-
-        if (waitrfd(sockfd, timeoutp) == -1)
-                return -1;
-
-        /* Completed or failed */
-        if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, &optlen) == -1) {
-                debug("getsockopt: %s", strerror(errno));
-                return -1;
-        }
-        if (optval != 0) {
-                errno = optval;
-                return -1;
-        }
-        unset_nonblock(sockfd);
-        return 0;
-}
-
-/*
  * Opens a TCP/IP connection to the remote server on the given host.
  * The address of the remote host will be returned in hostaddr.
  * If port is 0, the default port will be used.
@@ -500,7 +457,7 @@ ssh_connect_direct(struct ssh *ssh, const char *host, struct addrinfo *aitop,
     struct sockaddr_storage *hostaddr, u_short port, int family,
     int connection_attempts, int *timeout_ms, int want_keepalive)
 {
-        int on = 1;
+        int on = 1, saved_timeout_ms = *timeout_ms;
         int oerrno, sock = -1, attempt;
         char ntop[NI_MAXHOST], strport[NI_MAXSERV];
         struct addrinfo *ai;
@@ -544,6 +501,7 @@ ssh_connect_direct(struct ssh *ssh, const char *host, struct addrinfo *aitop,
                                 continue;
                         }
 
+                        *timeout_ms = saved_timeout_ms;
                         if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen,
                             timeout_ms) >= 0) {
                                 /* Successful connection. */
@@ -589,12 +547,20 @@ ssh_connect(struct ssh *ssh, const char *host, struct addrinfo *addrs,
     struct sockaddr_storage *hostaddr, u_short port, int family,
     int connection_attempts, int *timeout_ms, int want_keepalive)
 {
+        int in, out;
+
         if (options.proxy_command == NULL) {
                 return ssh_connect_direct(ssh, host, addrs, hostaddr, port,
                     family, connection_attempts, timeout_ms, want_keepalive);
         } else if (strcmp(options.proxy_command, "-") == 0) {
-                if ((ssh_packet_set_connection(ssh,
-                    STDIN_FILENO, STDOUT_FILENO)) == NULL)
+                if ((in = dup(STDIN_FILENO)) < 0 ||
+                    (out = dup(STDOUT_FILENO)) < 0) {
+                        if (in >= 0)
+                                close(in);
+                        error("%s: dup() in/out failed", __func__);
+                        return -1; /* ssh_packet_set_connection logs error */
+                }
+                if ((ssh_packet_set_connection(ssh, in, out)) == NULL)
                         return -1; /* ssh_packet_set_connection logs error */
                 return 0;
         } else if (options.proxy_use_fdpass) {
@@ -604,128 +570,26 @@ ssh_connect(struct ssh *ssh, const char *host, struct addrinfo *addrs,
         return ssh_proxy_connect(ssh, host, port, options.proxy_command);
 }
 
-static void
-send_client_banner(int connection_out, int minor1)
-{
-        /* Send our own protocol version identification. */
-        xasprintf(&client_version_string, "SSH-%d.%d-%.100s\r\n",
-            PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION);
-        if (atomicio(vwrite, connection_out, client_version_string,
-            strlen(client_version_string)) != strlen(client_version_string))
-                fatal("write: %.100s", strerror(errno));
-        chop(client_version_string);
-        debug("Local version string %.100s", client_version_string);
-}
-
-/*
- * Waits for the server identification string, and sends our own
- * identification string.
- */
-void
-ssh_exchange_identification(int timeout_ms)
-{
-        char buf[256], remote_version[256];     /* must be same size! */
-        int remote_major, remote_minor, mismatch;
-        int connection_in = packet_get_connection_in();
-        int connection_out = packet_get_connection_out();
-        u_int i, n;
-        size_t len;
-        int rc;
-
-        send_client_banner(connection_out, 0);
-
-        /* Read other side's version identification. */
-        for (n = 0;;) {
-                for (i = 0; i < sizeof(buf) - 1; i++) {
-                        if (timeout_ms > 0) {
-                                rc = waitrfd(connection_in, &timeout_ms);
-                                if (rc == -1 && errno == ETIMEDOUT) {
-                                        fatal("Connection timed out during "
-                                            "banner exchange");
-                                } else if (rc == -1) {
-                                        fatal("%s: %s",
-                                            __func__, strerror(errno));
-                                }
-                        }
-
-                        len = atomicio(read, connection_in, &buf[i], 1);
-                        if (len != 1 && errno == EPIPE)
-                                fatal("ssh_exchange_identification: "
-                                    "Connection closed by remote host");
-                        else if (len != 1)
-                                fatal("ssh_exchange_identification: "
-                                    "read: %.100s", strerror(errno));
-                        if (buf[i] == '\r') {
-                                buf[i] = '\n';
-                                buf[i + 1] = 0;
-                                continue;               /**XXX wait for \n */
-                        }
-                        if (buf[i] == '\n') {
-                                buf[i + 1] = 0;
-                                break;
-                        }
-                        if (++n > 65536)
-                                fatal("ssh_exchange_identification: "
-                                    "No banner received");
-                }
-                buf[sizeof(buf) - 1] = 0;
-                if (strncmp(buf, "SSH-", 4) == 0)
-                        break;
-                debug("ssh_exchange_identification: %s", buf);
-        }
-        server_version_string = xstrdup(buf);
-
-        /*
-         * Check that the versions match.  In future this might accept
-         * several versions and set appropriate flags to handle them.
-         */
-        if (sscanf(server_version_string, "SSH-%d.%d-%[^\n]\n",
-            &remote_major, &remote_minor, remote_version) != 3)
-                fatal("Bad remote protocol version identification: '%.100s'", buf);
-        debug("Remote protocol version %d.%d, remote software version %.100s",
-            remote_major, remote_minor, remote_version);
-
-        active_state->compat = compat_datafellows(remote_version);
-        mismatch = 0;
-
-        switch (remote_major) {
-        case 2:
-                break;
-        case 1:
-                if (remote_minor != 99)
-                        mismatch = 1;
-                break;
-        default:
-                mismatch = 1;
-                break;
-        }
-        if (mismatch)
-                fatal("Protocol major versions differ: %d vs. %d",
-                    PROTOCOL_MAJOR_2, remote_major);
-        if ((datafellows & SSH_BUG_RSASIGMD5) != 0)
-                logit("Server version \"%.100s\" uses unsafe RSA signature "
-                    "scheme; disabling use of RSA keys", remote_version);
-        chop(server_version_string);
-}
-
 /* defaults to 'no' */
 static int
-confirm(const char *prompt)
+confirm(const char *prompt, const char *fingerprint)
 {
         const char *msg, *again = "Please type 'yes' or 'no': ";
+        const char *again_fp = "Please type 'yes', 'no' or the fingerprint: ";
         char *p;
         int ret = -1;
 
         if (options.batch_mode)
                 return 0;
-        for (msg = prompt;;msg = again) {
+        for (msg = prompt;;msg = fingerprint ? again_fp : again) {
                 p = read_passphrase(msg, RP_ECHO);
                 if (p == NULL)
                         return 0;
                 p[strcspn(p, "\n")] = '\0';
                 if (p[0] == '\0' || strcasecmp(p, "no") == 0)
                         ret = 0;
-                else if (strcasecmp(p, "yes") == 0)
+                else if (strcasecmp(p, "yes") == 0 || (fingerprint != NULL &&
+                    strcasecmp(p, fingerprint) == 0))
                         ret = 1;
                 free(p);
                 if (ret != -1)
@@ -853,7 +717,7 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
         char msg[1024];
         const char *type;
         const struct hostkey_entry *host_found, *ip_found;
-        int len, cancelled_forwarding = 0;
+        int len, cancelled_forwarding = 0, confirmed;
         int local = sockaddr_is_local(hostaddr);
         int r, want_cert = sshkey_is_cert(host_key), host_ip_differ = 0;
         int hostkey_trusted = 0; /* Known or explicitly accepted by user */
@@ -1028,14 +892,15 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
                             "established%s\n"
                             "%s key fingerprint is %s.%s%s\n%s"
                             "Are you sure you want to continue connecting "
-                            "(yes/no)? ",
+                            "(yes/no/[fingerprint])? ",
                             host, ip, msg1, type, fp,
                             options.visual_host_key ? "\n" : "",
                             options.visual_host_key ? ra : "",
                             msg2);
                         free(ra);
+                        confirmed = confirm(msg, fp);
                         free(fp);
-                        if (!confirm(msg))
+                        if (!confirmed)
                                 goto fail;
                         hostkey_trusted = 1; /* user explicitly confirmed */
                 }
@@ -1229,7 +1094,7 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port,
                     SSH_STRICT_HOSTKEY_ASK) {
                         strlcat(msg, "\nAre you sure you want "
                             "to continue connecting (yes/no)? ", sizeof(msg));
-                        if (!confirm(msg))
+                        if (!confirm(msg, NULL))
                                 goto fail;
                 } else if (options.strict_host_key_checking !=
                     SSH_STRICT_HOSTKEY_OFF) {
@@ -1401,7 +1266,7 @@ out:
  * This function does not require super-user privileges.
  */
 void
-ssh_login(Sensitive *sensitive, const char *orighost,
+ssh_login(struct ssh *ssh, Sensitive *sensitive, const char *orighost,
     struct sockaddr *hostaddr, u_short port, struct passwd *pw, int timeout_ms)
 {
         char *host;
@@ -1415,37 +1280,20 @@ ssh_login(Sensitive *sensitive, const char *orighost,
         lowercase(host);
 
         /* Exchange protocol version identification strings with the server. */
-        ssh_exchange_identification(timeout_ms);
+        if (kex_exchange_identification(ssh, timeout_ms, NULL) != 0)
+                cleanup_exit(255); /* error already logged */
 
         /* Put the connection into non-blocking mode. */
-        packet_set_nonblocking();
+        ssh_packet_set_nonblocking(ssh);
 
         /* key exchange */
         /* authenticate user */
         debug("Authenticating to %s:%d as '%s'", host, port, server_user);
-        ssh_kex2(host, hostaddr, port);
-        ssh_userauth2(local_user, server_user, host, sensitive);
+        ssh_kex2(ssh, host, hostaddr, port);
+        ssh_userauth2(ssh, local_user, server_user, host, sensitive);
         free(local_user);
 }
 
-void
-ssh_put_password(char *password)
-{
-        int size;
-        char *padded;
-
-        if (datafellows & SSH_BUG_PASSWORDPAD) {
-                packet_put_cstring(password);
-                return;
-        }
-        size = ROUNDUP(strlen(password) + 1, 32);
-        padded = xcalloc(1, size);
-        strlcpy(padded, password, size);
-        packet_put_string(padded, size);
-        explicit_bzero(padded, size);
-        free(padded);
-}
-
 /* print all known host keys for a given host, but skip keys of given type */
 static int
 show_other_keys(struct hostkeys *hostkeys, struct sshkey *key)