diff options
Diffstat (limited to 'sshconnect.c')
| -rw-r--r-- | sshconnect.c | 827 |
1 files changed, 389 insertions, 438 deletions
diff --git a/sshconnect.c b/sshconnect.c index 9e515066..af08be41 100644 --- a/sshconnect.c +++ b/sshconnect.c @@ -1,4 +1,4 @@ -/* $OpenBSD: sshconnect.c,v 1.259 2015/01/28 22:36:00 djm Exp $ */ +/* $OpenBSD: sshconnect.c,v 1.329 2020/03/13 04:01:56 djm Exp $ */ /* * Author: Tatu Ylonen <ylo@cs.hut.fi> * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -15,7 +15,6 @@ #include "includes.h" -#include <sys/param.h> /* roundup */ #include <sys/types.h> #include <sys/wait.h> #include <sys/stat.h> @@ -24,6 +23,7 @@ # include <sys/time.h> #endif +#include <net/if.h> #include <netinet/in.h> #include <arpa/inet.h> @@ -35,76 +35,98 @@ #include <paths.h> #endif #include <pwd.h> +#ifdef HAVE_POLL_H +#include <poll.h> +#endif #include <signal.h> -#include <stdarg.h> #include <stdio.h> #include <stdlib.h> +#include <stdarg.h> #include <string.h> #include <unistd.h> +#ifdef HAVE_IFADDRS_H +# include <ifaddrs.h> +#endif #include "xmalloc.h" -#include "key.h" #include "hostfile.h" #include "ssh.h" -#include "rsa.h" -#include "buffer.h" +#include "sshbuf.h" #include "packet.h" -#include "uidswap.h" #include "compat.h" -#include "key.h" +#include "sshkey.h" #include "sshconnect.h" -#include "hostfile.h" #include "log.h" #include "misc.h" #include "readconf.h" #include "atomicio.h" #include "dns.h" -#include "roaming.h" #include "monitor_fdpass.h" #include "ssh2.h" #include "version.h" #include "authfile.h" #include "ssherr.h" +#include "authfd.h" +#include "kex.h" -char *client_version_string = NULL; -char *server_version_string = NULL; -Key *previous_host_key = NULL; +struct sshkey *previous_host_key = NULL; 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; -extern uid_t original_real_uid; -extern uid_t original_effective_uid; -static int show_other_keys(struct hostkeys *, Key *); -static void warn_changed_key(Key *); +static int show_other_keys(struct hostkeys *, struct sshkey *); +static void warn_changed_key(struct sshkey *); /* Expand a proxy command */ static char * expand_proxy_command(const char *proxy_command, const char *user, - const char *host, int port) + const char *host, const char *host_arg, int port) { char *tmp, *ret, strport[NI_MAXSERV]; snprintf(strport, sizeof strport, "%d", port); xasprintf(&tmp, "exec %s", proxy_command); - ret = percent_expand(tmp, "h", host, "p", strport, - "r", options.user, (char *)NULL); + ret = percent_expand(tmp, + "h", host, + "n", host_arg, + "p", strport, + "r", options.user, + (char *)NULL); free(tmp); 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. */ static int -ssh_proxy_fdpass_connect(const char *host, u_short port, - const char *proxy_command) +ssh_proxy_fdpass_connect(struct ssh *ssh, const char *host, + const char *host_arg, u_short port, const char *proxy_command) { char *command_string; int sp[2], sock; @@ -114,38 +136,39 @@ ssh_proxy_fdpass_connect(const char *host, u_short port, if ((shell = getenv("SHELL")) == NULL) shell = _PATH_BSHELL; - if (socketpair(AF_UNIX, SOCK_STREAM, 0, sp) < 0) + if (socketpair(AF_UNIX, SOCK_STREAM, 0, sp) == -1) fatal("Could not create socketpair to communicate with " "proxy dialer: %.100s", strerror(errno)); command_string = expand_proxy_command(proxy_command, options.user, - host, port); + host, host_arg, port); debug("Executing proxy dialer command: %.500s", command_string); /* Fork and execute the proxy command. */ if ((pid = fork()) == 0) { char *argv[10]; - /* Child. Permanently give up superuser privileges. */ - permanently_drop_suid(original_real_uid); - close(sp[1]); /* Redirect stdin and stdout. */ if (sp[0] != 0) { - if (dup2(sp[0], 0) < 0) + if (dup2(sp[0], 0) == -1) perror("dup2 stdin"); } if (sp[0] != 1) { - if (dup2(sp[0], 1) < 0) + if (dup2(sp[0], 1) == -1) perror("dup2 stdout"); } if (sp[0] >= 2) 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; @@ -160,20 +183,22 @@ ssh_proxy_fdpass_connect(const char *host, u_short port, exit(1); } /* Parent. */ - if (pid < 0) + if (pid == -1) fatal("fork failed: %.100s", strerror(errno)); close(sp[0]); free(command_string); if ((sock = mm_receive_fd(sp[1])) == -1) fatal("proxy dialer did not pass back a connection"); + close(sp[1]); while (waitpid(pid, NULL, 0) == -1) if (errno != EINTR) fatal("Couldn't wait for child: %s", strerror(errno)); /* Set the connection file descriptors. */ - packet_set_connection(sock, sock); + if (ssh_packet_set_connection(ssh, sock, sock) == NULL) + return -1; /* ssh_packet_set_connection logs error */ return 0; } @@ -182,7 +207,8 @@ ssh_proxy_fdpass_connect(const char *host, u_short port, * Connect to the given ssh server using a proxy command. */ static int -ssh_proxy_connect(const char *host, u_short port, const char *proxy_command) +ssh_proxy_connect(struct ssh *ssh, const char *host, const char *host_arg, + u_short port, const char *proxy_command) { char *command_string; int pin[2], pout[2]; @@ -193,36 +219,39 @@ ssh_proxy_connect(const char *host, u_short port, const char *proxy_command) shell = _PATH_BSHELL; /* Create pipes for communicating with the proxy. */ - if (pipe(pin) < 0 || pipe(pout) < 0) + if (pipe(pin) == -1 || pipe(pout) == -1) fatal("Could not create pipes to communicate with the proxy: %.100s", strerror(errno)); command_string = expand_proxy_command(proxy_command, options.user, - host, port); + host, host_arg, port); debug("Executing proxy command: %.500s", command_string); /* Fork and execute the proxy command. */ if ((pid = fork()) == 0) { char *argv[10]; - /* Child. Permanently give up superuser privileges. */ - permanently_drop_suid(original_real_uid); - /* Redirect stdin and stdout. */ close(pin[1]); if (pin[0] != 0) { - if (dup2(pin[0], 0) < 0) + if (dup2(pin[0], 0) == -1) perror("dup2 stdin"); close(pin[0]); } close(pout[0]); - if (dup2(pout[1], 1) < 0) + if (dup2(pout[1], 1) == -1) perror("dup2 stdout"); /* 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; @@ -230,13 +259,13 @@ ssh_proxy_connect(const char *host, u_short port, const char *proxy_command) /* Execute the proxy command. Note that we gave up any extra privileges above. */ - signal(SIGPIPE, SIG_DFL); + ssh_signal(SIGPIPE, SIG_DFL); execv(argv[0], argv); perror(argv[0]); exit(1); } /* Parent. */ - if (pid < 0) + if (pid == -1) fatal("fork failed: %.100s", strerror(errno)); else proxy_command_pid = pid; /* save pid to clean up later */ @@ -249,9 +278,9 @@ ssh_proxy_connect(const char *host, u_short port, const char *proxy_command) free(command_string); /* Set the connection file descriptors. */ - packet_set_connection(pout[0], pin[1]); + if (ssh_packet_set_connection(ssh, pout[0], pin[1]) == NULL) + return -1; /* ssh_packet_set_connection logs error */ - /* Indicate OK return */ return 0; } @@ -266,173 +295,179 @@ ssh_kill_proxy_command(void) kill(proxy_command_pid, SIGHUP); } +#ifdef HAVE_IFADDRS_H +/* + * Search a interface address list (returned from getifaddrs(3)) for an + * address that matches the desired address family on the specified interface. + * Returns 0 and fills in *resultp and *rlenp on success. Returns -1 on failure. + */ +static int +check_ifaddrs(const char *ifname, int af, const struct ifaddrs *ifaddrs, + struct sockaddr_storage *resultp, socklen_t *rlenp) +{ + struct sockaddr_in6 *sa6; + struct sockaddr_in *sa; + struct in6_addr *v6addr; + const struct ifaddrs *ifa; + int allow_local; + + /* + * Prefer addresses that are not loopback or linklocal, but use them + * if nothing else matches. + */ + for (allow_local = 0; allow_local < 2; allow_local++) { + for (ifa = ifaddrs; ifa != NULL; ifa = ifa->ifa_next) { + if (ifa->ifa_addr == NULL || ifa->ifa_name == NULL || + (ifa->ifa_flags & IFF_UP) == 0 || + ifa->ifa_addr->sa_family != af || + strcmp(ifa->ifa_name, options.bind_interface) != 0) + continue; + switch (ifa->ifa_addr->sa_family) { + case AF_INET: + sa = (struct sockaddr_in *)ifa->ifa_addr; + if (!allow_local && sa->sin_addr.s_addr == + htonl(INADDR_LOOPBACK)) + continue; + if (*rlenp < sizeof(struct sockaddr_in)) { + error("%s: v4 addr doesn't fit", + __func__); + return -1; + } + *rlenp = sizeof(struct sockaddr_in); + memcpy(resultp, sa, *rlenp); + return 0; + case AF_INET6: + sa6 = (struct sockaddr_in6 *)ifa->ifa_addr; + v6addr = &sa6->sin6_addr; + if (!allow_local && + (IN6_IS_ADDR_LINKLOCAL(v6addr) || + IN6_IS_ADDR_LOOPBACK(v6addr))) + continue; + if (*rlenp < sizeof(struct sockaddr_in6)) { + error("%s: v6 addr doesn't fit", + __func__); + return -1; + } + *rlenp = sizeof(struct sockaddr_in6); + memcpy(resultp, sa6, *rlenp); + return 0; + } + } + } + return -1; +} +#endif + /* - * Creates a (possibly privileged) socket for use as the ssh connection. + * Creates a socket for use as the ssh connection. */ static int -ssh_create_socket(int privileged, struct addrinfo *ai) +ssh_create_socket(struct addrinfo *ai) { - int sock, r, gaierr; + int sock, r; + struct sockaddr_storage bindaddr; + socklen_t bindaddrlen = 0; struct addrinfo hints, *res = NULL; +#ifdef HAVE_IFADDRS_H + struct ifaddrs *ifaddrs = NULL; +#endif + char ntop[NI_MAXHOST]; sock = socket(ai->ai_family, ai->ai_socktype, ai->ai_protocol); - if (sock < 0) { + if (sock == -1) { error("socket: %s", strerror(errno)); return -1; } fcntl(sock, F_SETFD, FD_CLOEXEC); /* Bind the socket to an alternative local IP address */ - if (options.bind_address == NULL && !privileged) + if (options.bind_address == NULL && options.bind_interface == NULL) return sock; - if (options.bind_address) { + if (options.bind_address != NULL) { memset(&hints, 0, sizeof(hints)); hints.ai_family = ai->ai_family; hints.ai_socktype = ai->ai_socktype; hints.ai_protocol = ai->ai_protocol; hints.ai_flags = AI_PASSIVE; - gaierr = getaddrinfo(options.bind_address, NULL, &hints, &res); - if (gaierr) { + if ((r = getaddrinfo(options.bind_address, NULL, + &hints, &res)) != 0) { error("getaddrinfo: %s: %s", options.bind_address, - ssh_gai_strerror(gaierr)); - close(sock); - return -1; + ssh_gai_strerror(r)); + goto fail; } - } - /* - * If we are running as root and want to connect to a privileged - * port, bind our own socket to a privileged port. - */ - if (privileged) { - PRIV_START; - r = bindresvport_sa(sock, res ? res->ai_addr : NULL); - PRIV_END; - if (r < 0) { - error("bindresvport_sa: af=%d %s", ai->ai_family, - strerror(errno)); + if (res == NULL) { + error("getaddrinfo: no addrs"); goto fail; } - } else { - if (bind(sock, res->ai_addr, res->ai_addrlen) < 0) { - error("bind: %s: %s", options.bind_address, - strerror(errno)); - fail: - close(sock); - freeaddrinfo(res); - return -1; + memcpy(&bindaddr, res->ai_addr, res->ai_addrlen); + bindaddrlen = res->ai_addrlen; + } else if (options.bind_interface != NULL) { +#ifdef HAVE_IFADDRS_H + if ((r = getifaddrs(&ifaddrs)) != 0) { + error("getifaddrs: %s: %s", options.bind_interface, + strerror(errno)); + goto fail; } + bindaddrlen = sizeof(bindaddr); + if (check_ifaddrs(options.bind_interface, ai->ai_family, + ifaddrs, &bindaddr, &bindaddrlen) != 0) { + logit("getifaddrs: %s: no suitable addresses", + options.bind_interface); + goto fail; + } +#else + error("BindInterface not supported on this platform."); +#endif + } + if ((r = getnameinfo((struct sockaddr *)&bindaddr, bindaddrlen, + ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST)) != 0) { + error("%s: getnameinfo failed: %s", __func__, + ssh_gai_strerror(r)); + goto fail; + } + if (bind(sock, (struct sockaddr *)&bindaddr, bindaddrlen) != 0) { + error("bind %s: %s", ntop, strerror(errno)); + goto fail; } + debug("%s: bound to %s", __func__, ntop); + /* success */ + goto out; +fail: + close(sock); + sock = -1; + out: if (res != NULL) freeaddrinfo(res); +#ifdef HAVE_IFADDRS_H + if (ifaddrs != NULL) + freeifaddrs(ifaddrs); +#endif return sock; } -static int -timeout_connect(int sockfd, const struct sockaddr *serv_addr, - socklen_t addrlen, int *timeoutp) -{ - fd_set *fdset; - struct timeval tv, t_start; - socklen_t optlen; - int optval, rc, result = -1; - - gettimeofday(&t_start, NULL); - - if (*timeoutp <= 0) { - result = connect(sockfd, serv_addr, addrlen); - goto done; - } - - set_nonblock(sockfd); - rc = connect(sockfd, serv_addr, addrlen); - if (rc == 0) { - unset_nonblock(sockfd); - result = 0; - goto done; - } - if (errno != EINPROGRESS) { - result = -1; - goto done; - } - - fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS), - sizeof(fd_mask)); - FD_SET(sockfd, fdset); - ms_to_timeval(&tv, *timeoutp); - - for (;;) { - rc = select(sockfd + 1, NULL, fdset, NULL, &tv); - if (rc != -1 || errno != EINTR) - break; - } - - switch (rc) { - case 0: - /* Timed out */ - errno = ETIMEDOUT; - break; - case -1: - /* Select error */ - debug("select: %s", strerror(errno)); - break; - case 1: - /* Completed or failed */ - optval = 0; - optlen = sizeof(optval); - if (getsockopt(sockfd, SOL_SOCKET, SO_ERROR, &optval, - &optlen) == -1) { - debug("getsockopt: %s", strerror(errno)); - break; - } - if (optval != 0) { - errno = optval; - break; - } - result = 0; - unset_nonblock(sockfd); - break; - default: - /* Should not occur */ - fatal("Bogus return (%d) from select()", rc); - } - - free(fdset); - - done: - if (result == 0 && *timeoutp > 0) { - ms_subtract_diff(&t_start, timeoutp); - if (*timeoutp <= 0) { - errno = ETIMEDOUT; - result = -1; - } - } - - return (result); -} - /* * 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. If needpriv is true, - * a privileged port will be allocated to make the connection. - * This requires super-user privileges if needpriv is true. + * If port is 0, the default port will be used. * Connection_attempts specifies the maximum number of tries (one per * second). If proxy_command is non-NULL, it specifies the command (with %h * and %p substituted for host and port, respectively) to use to contact * the daemon. */ static int -ssh_connect_direct(const char *host, struct addrinfo *aitop, +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 needpriv) + int connection_attempts, int *timeout_ms, int want_keepalive) { - int on = 1; - int sock = -1, attempt; + int on = 1, saved_timeout_ms = *timeout_ms; + int oerrno, sock = -1, attempt; char ntop[NI_MAXHOST], strport[NI_MAXSERV]; struct addrinfo *ai; - debug2("ssh_connect: needpriv %d", needpriv); + debug2("%s", __func__); + memset(ntop, 0, sizeof(ntop)); + memset(strport, 0, sizeof(strport)); for (attempt = 0; attempt < connection_attempts; attempt++) { if (attempt > 0) { @@ -446,33 +481,42 @@ ssh_connect_direct(const char *host, struct addrinfo *aitop, */ for (ai = aitop; ai; ai = ai->ai_next) { if (ai->ai_family != AF_INET && - ai->ai_family != AF_INET6) + ai->ai_family != AF_INET6) { + errno = EAFNOSUPPORT; continue; + } if (getnameinfo(ai->ai_addr, ai->ai_addrlen, ntop, sizeof(ntop), strport, sizeof(strport), NI_NUMERICHOST|NI_NUMERICSERV) != 0) { - error("ssh_connect: getnameinfo failed"); + oerrno = errno; + error("%s: getnameinfo failed", __func__); + errno = oerrno; continue; } debug("Connecting to %.200s [%.100s] port %s.", host, ntop, strport); /* Create a socket for connecting. */ - sock = ssh_create_socket(needpriv, ai); - if (sock < 0) + sock = ssh_create_socket(ai); + if (sock < 0) { /* Any error is already output */ + errno = 0; continue; + } + *timeout_ms = saved_timeout_ms; if (timeout_connect(sock, ai->ai_addr, ai->ai_addrlen, timeout_ms) >= 0) { /* Successful connection. */ memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen); break; } else { + oerrno = errno; debug("connect to address %s port %s: %s", ntop, strport, strerror(errno)); close(sock); sock = -1; + errno = oerrno; } } if (sock != -1) @@ -482,8 +526,8 @@ ssh_connect_direct(const char *host, struct addrinfo *aitop, /* Return failure if we didn't get a successful connection. */ if (sock == -1) { error("ssh: connect to host %s port %s: %s", - host, strport, strerror(errno)); - return (-1); + host, strport, errno == 0 ? "failure" : strerror(errno)); + return -1; } debug("Connection established."); @@ -491,233 +535,96 @@ ssh_connect_direct(const char *host, struct addrinfo *aitop, /* Set SO_KEEPALIVE if requested. */ if (want_keepalive && setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on, - sizeof(on)) < 0) + sizeof(on)) == -1) error("setsockopt SO_KEEPALIVE: %.100s", strerror(errno)); /* Set the connection. */ - packet_set_connection(sock, sock); + if (ssh_packet_set_connection(ssh, sock, sock) == NULL) + return -1; /* ssh_packet_set_connection logs error */ return 0; } int -ssh_connect(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 needpriv) +ssh_connect(struct ssh *ssh, const char *host, const char *host_arg, + 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(host, addrs, hostaddr, port, family, - connection_attempts, timeout_ms, want_keepalive, needpriv); + return ssh_connect_direct(ssh, host, addrs, hostaddr, port, + family, connection_attempts, timeout_ms, want_keepalive); } else if (strcmp(options.proxy_command, "-") == 0) { - packet_set_connection(STDIN_FILENO, STDOUT_FILENO); - return 0; /* Always succeeds */ + if ((in = dup(STDIN_FILENO)) == -1 || + (out = dup(STDOUT_FILENO)) == -1) { + 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) { - return ssh_proxy_fdpass_connect(host, port, + return ssh_proxy_fdpass_connect(ssh, host, host_arg, port, options.proxy_command); } - return ssh_proxy_connect(host, port, options.proxy_command); -} - -static void -send_client_banner(int connection_out, int minor1) -{ - /* Send our own protocol version identification. */ - if (compat20) { - xasprintf(&client_version_string, "SSH-%d.%d-%.100s\r\n", - PROTOCOL_MAJOR_2, PROTOCOL_MINOR_2, SSH_VERSION); - } else { - xasprintf(&client_version_string, "SSH-%d.%d-%.100s\n", - PROTOCOL_MAJOR_1, minor1, SSH_VERSION); - } - if (roaming_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(); - int minor1 = PROTOCOL_MINOR_1, client_banner_sent = 0; - u_int i, n; - size_t len; - int fdsetsz, remaining, rc; - struct timeval t_start, t_remaining; - fd_set *fdset; - - fdsetsz = howmany(connection_in + 1, NFDBITS) * sizeof(fd_mask); - fdset = xcalloc(1, fdsetsz); - - /* - * If we are SSH2-only then we can send the banner immediately and - * save a round-trip. - */ - if (options.protocol == SSH_PROTO_2) { - enable_compat20(); - send_client_banner(connection_out, 0); - client_banner_sent = 1; - } - - /* Read other side's version identification. */ - remaining = timeout_ms; - for (n = 0;;) { - for (i = 0; i < sizeof(buf) - 1; i++) { - if (timeout_ms > 0) { - gettimeofday(&t_start, NULL); - ms_to_timeval(&t_remaining, remaining); - FD_SET(connection_in, fdset); - rc = select(connection_in + 1, fdset, NULL, - fdset, &t_remaining); - ms_subtract_diff(&t_start, &remaining); - if (rc == 0 || remaining <= 0) - fatal("Connection timed out during " - "banner exchange"); - if (rc == -1) { - if (errno == EINTR) - continue; - fatal("ssh_exchange_identification: " - "select: %s", strerror(errno)); - } - } - - len = roaming_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); - free(fdset); - - /* - * 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 1: - if (remote_minor == 99 && - (options.protocol & SSH_PROTO_2) && - !(options.protocol & SSH_PROTO_1_PREFERRED)) { - enable_compat20(); - break; - } - if (!(options.protocol & SSH_PROTO_1)) { - mismatch = 1; - break; - } - if (remote_minor < 3) { - fatal("Remote machine has too old SSH software version."); - } else if (remote_minor == 3 || remote_minor == 4) { - /* We speak 1.3, too. */ - enable_compat13(); - minor1 = 3; - if (options.forward_agent) { - logit("Agent forwarding disabled for protocol 1.3"); - options.forward_agent = 0; - } - } - break; - case 2: - if (options.protocol & SSH_PROTO_2) { - enable_compat20(); - break; - } - /* FALLTHROUGH */ - default: - mismatch = 1; - break; - } - if (mismatch) - fatal("Protocol major versions differ: %d vs. %d", - (options.protocol & SSH_PROTO_2) ? PROTOCOL_MAJOR_2 : PROTOCOL_MAJOR_1, - remote_major); - if ((datafellows & SSH_BUG_DERIVEKEY) != 0) - fatal("Server version \"%.100s\" uses unsafe key agreement; " - "refusing connection", remote_version); - if ((datafellows & SSH_BUG_RSASIGMD5) != 0) - logit("Server version \"%.100s\" uses unsafe RSA signature " - "scheme; disabling use of RSA keys", remote_version); - if (!client_banner_sent) - send_client_banner(connection_out, minor1); - chop(server_version_string); + return ssh_proxy_connect(ssh, host, host_arg, port, + options.proxy_command); } /* 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': "; - char *p; + const char *again_fp = "Please type 'yes', 'no' or the fingerprint: "; + char *p, *cp; int ret = -1; if (options.batch_mode) return 0; - for (msg = prompt;;msg = again) { - p = read_passphrase(msg, RP_ECHO); - if (p == NULL || - (p[0] == '\0') || (p[0] == '\n') || - strncasecmp(p, "no", 2) == 0) + for (msg = prompt;;msg = fingerprint ? again_fp : again) { + cp = p = read_passphrase(msg, RP_ECHO); + if (p == NULL) + return 0; + p += strspn(p, " \t"); /* skip leading whitespace */ + p[strcspn(p, " \t\n")] = '\0'; /* remove trailing whitespace */ + if (p[0] == '\0' || strcasecmp(p, "no") == 0) ret = 0; - if (p && strncasecmp(p, "yes", 3) == 0) + else if (strcasecmp(p, "yes") == 0 || (fingerprint != NULL && + strcasecmp(p, fingerprint) == 0)) ret = 1; - free(p); + free(cp); if (ret != -1) return ret; } } static int -check_host_cert(const char *host, const Key *host_key) +check_host_cert(const char *host, const struct sshkey *key) { const char *reason; + int r; - if (key_cert_check_authority(host_key, 1, 0, host, &reason) != 0) { + if (sshkey_cert_check_authority(key, 1, 0, host, &reason) != 0) { error("%s", reason); return 0; } - if (buffer_len(host_key->cert->critical) != 0) { + if (sshbuf_len(key->cert->critical) != 0) { error("Certificate for %s contains unsupported " "critical options(s)", host); return 0; } + if ((r = sshkey_check_cert_sigtype(key, + options.ca_sign_algorithms)) != 0) { + logit("%s: certificate signature algorithm %s: %s", __func__, + (key->cert == NULL || key->cert->signature_type == NULL) ? + "(null)" : key->cert->signature_type, ssh_err(r)); + return 0; + } + return 1; } @@ -803,21 +710,21 @@ get_hostfile_hostname_ipaddr(char *hostname, struct sockaddr *hostaddr, #define ROQUIET 2 static int check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, - Key *host_key, int readonly, + struct sshkey *host_key, int readonly, char **user_hostfiles, u_int num_user_hostfiles, char **system_hostfiles, u_int num_system_hostfiles) { HostStatus host_status; HostStatus ip_status; - Key *raw_key = NULL; + struct sshkey *raw_key = NULL; char *ip = NULL, *host = NULL; char hostline[1000], *hostp, *fp, *ra; 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 = key_is_cert(host_key), host_ip_differ = 0; + int r, want_cert = sshkey_is_cert(host_key), host_ip_differ = 0; int hostkey_trusted = 0; /* Known or explicitly accepted by user */ struct hostkeys *host_hostkeys, *ip_hostkeys; u_int i; @@ -868,8 +775,8 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, retry: /* Reload these as they may have changed on cert->key downgrade */ - want_cert = key_is_cert(host_key); - type = key_type(host_key); + want_cert = sshkey_is_cert(host_key); + type = sshkey_type(host_key); /* * Check if the host key is present in the user's list of known @@ -887,9 +794,9 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, ip_status = check_key_in_hostkeys(ip_hostkeys, host_key, &ip_found); if (host_status == HOST_CHANGED && - (ip_status != HOST_CHANGED || + (ip_status != HOST_CHANGED || (ip_found != NULL && - !key_equal(ip_found->key, host_found->key)))) + !sshkey_equal(ip_found->key, host_found->key)))) host_ip_differ = 1; } else ip_status = host_status; @@ -901,7 +808,9 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, host, type, want_cert ? "certificate" : "key"); debug("Found %s in %s:%lu", want_cert ? "CA key" : "key", host_found->file, host_found->line); - if (want_cert && !check_host_cert(hostname, host_key)) + if (want_cert && + !check_host_cert(options.host_key_alias == NULL ? + hostname : options.host_key_alias, host_key)) goto fail; if (options.check_host_ip && ip_status == HOST_NEW) { if (readonly || want_cert) @@ -912,7 +821,7 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, host_key, options.hash_known_hosts)) logit("Failed to add the %s host key for IP " "address '%.128s' to the list of known " - "hosts (%.30s).", type, ip, + "hosts (%.500s).", type, ip, user_hostfiles[0]); else logit("Warning: Permanently added the %s host " @@ -925,7 +834,7 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, options.fingerprint_hash, SSH_FP_RANDOMART); if (fp == NULL || ra == NULL) fatal("%s: sshkey_fingerprint fail", __func__); - logit("Host key fingerprint is %s\n%s\n", fp, ra); + logit("Host key fingerprint is %s\n%s", fp, ra); free(ra); free(fp); } @@ -945,7 +854,8 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, if (readonly || want_cert) goto fail; /* The host is new. */ - if (options.strict_host_key_checking == 1) { + if (options.strict_host_key_checking == + SSH_STRICT_HOSTKEY_YES) { /* * User has requested strict host key checking. We * will not add the host key automatically. The only @@ -954,7 +864,8 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, error("No %s host key is known for %.200s and you " "have requested strict checking.", type, host); goto fail; - } else if (options.strict_host_key_checking == 2) { + } else if (options.strict_host_key_checking == + SSH_STRICT_HOSTKEY_ASK) { char msg1[1024], msg2[1024]; if (show_other_keys(host_hostkeys, host_key)) @@ -986,20 +897,21 @@ 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 */ } /* - * If not in strict mode, add the key automatically to the - * local known_hosts file. + * If in "new" or "off" strict mode, add the key automatically + * to the local known_hosts file. */ if (options.check_host_ip && ip_status == HOST_NEW) { snprintf(hostline, sizeof(hostline), "%s,%s", host, ip); @@ -1041,7 +953,8 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, * If strict host key checking is in use, the user will have * to edit the key manually and we can only abort. */ - if (options.strict_host_key_checking) { + if (options.strict_host_key_checking != + SSH_STRICT_HOSTKEY_OFF) { error("%s host key for %.200s was revoked and you have " "requested strict checking.", type, host); goto fail; @@ -1086,14 +999,16 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, warn_changed_key(host_key); error("Add correct host key in %.100s to get rid of this message.", user_hostfiles[0]); - error("Offending %s key in %s:%lu", key_type(host_found->key), + error("Offending %s key in %s:%lu", + sshkey_type(host_found->key), host_found->file, host_found->line); /* * If strict host key checking is in use, the user will have * to edit the key manually and we can only abort. */ - if (options.strict_host_key_checking) { + if (options.strict_host_key_checking != + SSH_STRICT_HOSTKEY_OFF) { error("%s host key for %.200s has changed and you have " "requested strict checking.", type, host); goto fail; @@ -1180,15 +1095,17 @@ check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, "\nMatching host key in %s:%lu", host_found->file, host_found->line); } - if (options.strict_host_key_checking == 1) { - logit("%s", msg); - error("Exiting, you have requested strict checking."); - goto fail; - } else if (options.strict_host_key_checking == 2) { + if (options.strict_host_key_checking == + 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) { + logit("%s", msg); + error("Exiting, you have requested strict checking."); + goto fail; } else { logit("%s", msg); } @@ -1215,14 +1132,15 @@ fail: * search normally. */ debug("No matching CA found. Retry with plain key"); - raw_key = key_from_private(host_key); - if (key_drop_cert(raw_key) != 0) - fatal("Couldn't drop certificate"); + if ((r = sshkey_from_private(host_key, &raw_key)) != 0) + fatal("%s: sshkey_from_private: %s", + __func__, ssh_err(r)); + if ((r = sshkey_drop_cert(raw_key)) != 0) + fatal("Couldn't drop certificate: %s", ssh_err(r)); host_key = raw_key; goto retry; } - if (raw_key != NULL) - key_free(raw_key); + sshkey_free(raw_key); free(ip); free(host); if (host_hostkeys != NULL) @@ -1234,10 +1152,11 @@ fail: /* returns 0 if key verifies or -1 if key does NOT verify */ int -verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key) +verify_host_key(char *host, struct sockaddr *hostaddr, struct sshkey *host_key) { + u_int i; int r = -1, flags = 0; - char *fp = NULL; + char valid[64], *fp = NULL, *cafp = NULL; struct sshkey *plain = NULL; if ((fp = sshkey_fingerprint(host_key, @@ -1247,8 +1166,30 @@ verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key) goto out; } - debug("Server host key: %s %s", - compat20 ? sshkey_ssh_name(host_key) : sshkey_type(host_key), fp); + if (sshkey_is_cert(host_key)) { + if ((cafp = sshkey_fingerprint(host_key->cert->signature_key, + options.fingerprint_hash, SSH_FP_DEFAULT)) == NULL) { + error("%s: fingerprint CA key: %s", + __func__, ssh_err(r)); + r = -1; + goto out; + } + sshkey_format_cert_validity(host_key->cert, + valid, sizeof(valid)); + debug("Server host certificate: %s %s, serial %llu " + "ID \"%s\" CA %s %s valid %s", + sshkey_ssh_name(host_key), fp, + (unsigned long long)host_key->cert->serial, + host_key->cert->key_id, + sshkey_ssh_name(host_key->cert->signature_key), cafp, + valid); + for (i = 0; i < host_key->cert->nprincipals; i++) { + debug2("Server host certificate hostname: %s", + host_key->cert->principals[i]); + } + } else { + debug("Server host key: %s %s", sshkey_ssh_name(host_key), fp); + } if (sshkey_equal(previous_host_key, host_key)) { debug2("%s: server host key %s %s matches cached key", @@ -1313,9 +1254,10 @@ verify_host_key(char *host, struct sockaddr *hostaddr, Key *host_key) out: sshkey_free(plain); free(fp); + free(cafp); if (r == 0 && host_key != NULL) { - key_free(previous_host_key); - previous_host_key = key_from_private(host_key); + sshkey_free(previous_host_key); + r = sshkey_from_private(host_key, &previous_host_key); } return r; @@ -1329,11 +1271,12 @@ 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; char *server_user, *local_user; + int r; local_user = xstrdup(pw->pw_name); server_user = options.user ? options.user : local_user; @@ -1343,55 +1286,31 @@ ssh_login(Sensitive *sensitive, const char *orighost, lowercase(host); /* Exchange protocol version identification strings with the server. */ - ssh_exchange_identification(timeout_ms); + if ((r = kex_exchange_identification(ssh, timeout_ms, NULL)) != 0) + sshpkt_fatal(ssh, r, "banner exchange"); /* Put the connection into non-blocking mode. */ - packet_set_nonblocking(); + ssh_packet_set_nonblocking(ssh); /* key exchange */ /* authenticate user */ - if (compat20) { - ssh_kex2(host, hostaddr, port); - ssh_userauth2(local_user, server_user, host, sensitive); - } else { -#ifdef WITH_SSH1 - ssh_kex(host, hostaddr); - ssh_userauth1(local_user, server_user, host, sensitive); -#else - fatal("ssh1 is not unsupported"); -#endif - } + debug("Authenticating to %s:%d as '%s'", host, port, server_user); + 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); + free(host); } /* print all known host keys for a given host, but skip keys of given type */ static int -show_other_keys(struct hostkeys *hostkeys, Key *key) +show_other_keys(struct hostkeys *hostkeys, struct sshkey *key) { int type[] = { - KEY_RSA1, KEY_RSA, KEY_DSA, KEY_ECDSA, KEY_ED25519, + KEY_XMSS, -1 }; int i, ret = 0; @@ -1412,9 +1331,9 @@ show_other_keys(struct hostkeys *hostkeys, Key *key) logit("WARNING: %s key found for host %s\n" "in %s:%lu\n" "%s key fingerprint %s.", - key_type(found->key), + sshkey_type(found->key), found->host, found->file, found->line, - key_type(found->key), fp); + sshkey_type(found->key), fp); if (options.visual_host_key) logit("%s", ra); free(ra); @@ -1425,7 +1344,7 @@ show_other_keys(struct hostkeys *hostkeys, Key *key) } static void -warn_changed_key(Key *host_key) +warn_changed_key(struct sshkey *host_key) { char *fp; @@ -1441,7 +1360,7 @@ warn_changed_key(Key *host_key) error("Someone could be eavesdropping on you right now (man-in-the-middle attack)!"); error("It is also possible that a host key has just been changed."); error("The fingerprint for the %s key sent by the remote host is\n%s.", - key_type(host_key), fp); + sshkey_type(host_key), fp); error("Please contact your system administrator."); free(fp); @@ -1465,10 +1384,10 @@ ssh_local_cmd(const char *args) if ((shell = getenv("SHELL")) == NULL || *shell == '\0') shell = _PATH_BSHELL; - osighand = signal(SIGCHLD, SIG_DFL); + osighand = ssh_signal(SIGCHLD, SIG_DFL); pid = fork(); if (pid == 0) { - signal(SIGPIPE, SIG_DFL); + ssh_signal(SIGPIPE, SIG_DFL); debug3("Executing %s -c \"%s\"", shell, args); execl(shell, shell, "-c", args, (char *)NULL); error("Couldn't execute %s -c \"%s\": %s", @@ -1479,10 +1398,42 @@ ssh_local_cmd(const char *args) while (waitpid(pid, &status, 0) == -1) if (errno != EINTR) fatal("Couldn't wait for child: %s", strerror(errno)); - signal(SIGCHLD, osighand); + ssh_signal(SIGCHLD, osighand); if (!WIFEXITED(status)) return (1); return (WEXITSTATUS(status)); } + +void +maybe_add_key_to_agent(const char *authfile, struct sshkey *private, + const char *comment, const char *passphrase) +{ + int auth_sock = -1, r; + const char *skprovider = NULL; + + if (options.add_keys_to_agent == 0) + return; + + if ((r = ssh_get_authentication_socket(&auth_sock)) != 0) { + debug3("no authentication agent, not adding key"); + return; + } + + if (options.add_keys_to_agent == 2 && + !ask_permission("Add key %s (%s) to agent?", authfile, comment)) { + debug3("user denied adding this key"); + close(auth_sock); + return; + } + if (sshkey_is_sk(private)) + skprovider = options.sk_provider; + if ((r = ssh_add_identity_constrained(auth_sock, private, + comment == NULL ? authfile : comment, 0, + (options.add_keys_to_agent == 3), 0, skprovider)) == 0) + debug("identity added to agent: %s", authfile); + else + debug("could not add identity to agent: %s (%d)", authfile, r); + close(auth_sock); +} |