=================================================================== RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/sshconnect.c,v retrieving revision 1.115 retrieving revision 1.115.2.4 diff -u -r1.115 -r1.115.2.4 --- src/usr.bin/ssh/sshconnect.c 2001/10/08 19:05:05 1.115 +++ src/usr.bin/ssh/sshconnect.c 2002/10/11 14:53:07 1.115.2.4 @@ -13,7 +13,7 @@ */ #include "includes.h" -RCSID("$OpenBSD: sshconnect.c,v 1.115 2001/10/08 19:05:05 markus Exp $"); +RCSID("$OpenBSD: sshconnect.c,v 1.115.2.4 2002/10/11 14:53:07 miod Exp $"); #include @@ -31,40 +31,25 @@ #include "readconf.h" #include "atomicio.h" #include "misc.h" +#include "readpass.h" char *client_version_string = NULL; char *server_version_string = NULL; +/* import */ extern Options options; extern char *__progname; +extern uid_t original_real_uid; +extern uid_t original_effective_uid; +extern pid_t proxy_command_pid; -static const char * -sockaddr_ntop(struct sockaddr *sa) -{ - void *addr; - static char addrbuf[INET6_ADDRSTRLEN]; +static int show_other_keys(const char *, Key *); - switch (sa->sa_family) { - case AF_INET: - addr = &((struct sockaddr_in *)sa)->sin_addr; - break; - case AF_INET6: - addr = &((struct sockaddr_in6 *)sa)->sin6_addr; - break; - default: - /* This case should be protected against elsewhere */ - abort(); - } - inet_ntop(sa->sa_family, addr, addrbuf, sizeof(addrbuf)); - return addrbuf; -} - /* * Connect to the given ssh server using a proxy command. */ static int -ssh_proxy_connect(const char *host, u_short port, struct passwd *pw, - const char *proxy_command) +ssh_proxy_connect(const char *host, u_short port, const char *proxy_command) { Buffer command; const char *cp; @@ -76,9 +61,16 @@ /* Convert the port number into a string. */ snprintf(strport, sizeof strport, "%hu", port); - /* Build the final command string in the buffer by making the - appropriate substitutions to the given proxy command. */ + /* + * Build the final command string in the buffer by making the + * appropriate substitutions to the given proxy command. + * + * Use "exec" to avoid "sh -c" processes on some platforms + * (e.g. Solaris) + */ buffer_init(&command); + buffer_append(&command, "exec ", 5); + for (cp = proxy_command; *cp; cp++) { if (cp[0] == '%' && cp[1] == '%') { buffer_append(&command, "%", 1); @@ -105,7 +97,7 @@ /* Create pipes for communicating with the proxy. */ if (pipe(pin) < 0 || pipe(pout) < 0) fatal("Could not create pipes to communicate with the proxy: %.100s", - strerror(errno)); + strerror(errno)); debug("Executing proxy command: %.500s", command_string); @@ -114,7 +106,8 @@ char *argv[10]; /* Child. Permanently give up superuser privileges. */ - permanently_set_uid(pw); + seteuid(original_real_uid); + setuid(original_real_uid); /* Redirect stdin and stdout. */ close(pin[1]); @@ -145,6 +138,8 @@ /* Parent. */ if (pid < 0) fatal("fork failed: %.100s", strerror(errno)); + else + proxy_command_pid = pid; /* save pid to clean up later */ /* Close child side of the descriptors. */ close(pin[0]); @@ -164,7 +159,7 @@ * Creates a (possibly privileged) socket for use as the ssh connection. */ static int -ssh_create_socket(struct passwd *pw, int privileged, int family) +ssh_create_socket(int privileged, int family) { int sock, gaierr; struct addrinfo hints, *res; @@ -175,22 +170,18 @@ */ if (privileged) { int p = IPPORT_RESERVED - 1; + PRIV_START; sock = rresvport_af(&p, family); + PRIV_END; if (sock < 0) error("rresvport: af=%d %.100s", family, strerror(errno)); else debug("Allocated local port %d.", p); return sock; } - /* - * Just create an ordinary socket on arbitrary port. We use - * the user's uid to create the socket. - */ - temporarily_use_uid(pw); sock = socket(family, SOCK_STREAM, 0); if (sock < 0) error("socket: %.100s", strerror(errno)); - restore_uid(); /* Bind the socket to an alternative local IP address */ if (options.bind_address == NULL) @@ -220,9 +211,9 @@ /* * 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 anonymous is zero, + * 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 anonymous is false. + * This requires super-user privileges if needpriv is true. * 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 @@ -237,14 +228,13 @@ int ssh_connect(const char *host, struct sockaddr_storage * hostaddr, u_short port, int family, int connection_attempts, - int anonymous, struct passwd *pw, const char *proxy_command) + int needpriv, const char *proxy_command) { int gaierr; int on = 1; int sock = -1, attempt; char ntop[NI_MAXHOST], strport[NI_MAXSERV]; struct addrinfo hints, *ai, *aitop; - struct linger linger; struct servent *sp; /* * Did we get only other errors than "Connection refused" (which @@ -253,8 +243,7 @@ */ int full_failure = 1; - debug("ssh_connect: getuid %u geteuid %u anon %d", - (u_int) getuid(), (u_int) geteuid(), anonymous); + debug("ssh_connect: needpriv %d", needpriv); /* Get default port if port has not been set. */ if (port == 0) { @@ -266,14 +255,14 @@ } /* If a proxy command is given, connect using it. */ if (proxy_command != NULL) - return ssh_proxy_connect(host, port, pw, proxy_command); + return ssh_proxy_connect(host, port, proxy_command); /* No proxy command. */ memset(&hints, 0, sizeof(hints)); hints.ai_family = family; hints.ai_socktype = SOCK_STREAM; - snprintf(strport, sizeof strport, "%d", port); + snprintf(strport, sizeof strport, "%u", port); if ((gaierr = getaddrinfo(host, strport, &hints, &aitop)) != 0) fatal("%s: %.100s: %s", __progname, host, gai_strerror(gaierr)); @@ -302,37 +291,26 @@ host, ntop, strport); /* Create a socket for connecting. */ - sock = ssh_create_socket(pw, - !anonymous && geteuid() == 0, - ai->ai_family); + sock = ssh_create_socket(needpriv, ai->ai_family); if (sock < 0) /* Any error is already output */ continue; - /* Connect to the host. We use the user's uid in the - * hope that it will help with tcp_wrappers showing - * the remote uid as root. - */ - temporarily_use_uid(pw); if (connect(sock, ai->ai_addr, ai->ai_addrlen) >= 0) { /* Successful connection. */ memcpy(hostaddr, ai->ai_addr, ai->ai_addrlen); - restore_uid(); break; } else { if (errno == ECONNREFUSED) full_failure = 0; - log("ssh: connect to address %s port %s: %s", - sockaddr_ntop(ai->ai_addr), strport, - strerror(errno)); - restore_uid(); + debug("connect to address %s port %s: %s", + ntop, strport, strerror(errno)); /* * Close the failed socket; there appear to * be some problems when reusing a socket for * which connect() has already returned an * error. */ - shutdown(sock, SHUT_RDWR); close(sock); } } @@ -349,20 +327,14 @@ freeaddrinfo(aitop); /* Return failure if we didn't get a successful connection. */ - if (attempt >= connection_attempts) + if (attempt >= connection_attempts) { + log("ssh: connect to host %s port %s: %s", + host, strport, strerror(errno)); return full_failure ? ECONNABORTED : ECONNREFUSED; + } debug("Connection established."); - /* - * Set socket options. We would like the socket to disappear as soon - * as it has been closed for whatever reason. - */ - /* setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, (void *)&on, sizeof(on)); */ - linger.l_onoff = 1; - linger.l_linger = 5; - setsockopt(sock, SOL_SOCKET, SO_LINGER, (void *)&linger, sizeof(linger)); - /* Set keepalives if requested. */ if (options.keepalives && setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE, (void *)&on, @@ -421,12 +393,12 @@ &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); + remote_major, remote_minor, remote_version); compat_datafellows(remote_version); mismatch = 0; - switch(remote_major) { + switch (remote_major) { case 1: if (remote_minor == 99 && (options.protocol & SSH_PROTO_2) && @@ -481,40 +453,24 @@ static int confirm(const char *prompt) { - char buf[1024]; - FILE *f; - int retval = -1; + const char *msg, *again = "Please type 'yes' or 'no': "; + char *p; + int ret = -1; if (options.batch_mode) return 0; - if (isatty(STDIN_FILENO)) - f = stdin; - else - f = fopen(_PATH_TTY, "rw"); - if (f == NULL) - return 0; - fflush(stdout); - fprintf(stderr, "%s", prompt); - while (1) { - if (fgets(buf, sizeof(buf), f) == NULL) { - fprintf(stderr, "\n"); - strlcpy(buf, "no", sizeof buf); - } - /* Remove newline from response. */ - if (strchr(buf, '\n')) - *strchr(buf, '\n') = 0; - if (strcmp(buf, "yes") == 0) - retval = 1; - else if (strcmp(buf, "no") == 0) - retval = 0; - else - fprintf(stderr, "Please type 'yes' or 'no': "); - - if (retval != -1) { - if (f != stdin) - fclose(f); - return retval; - } + 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) + ret = 0; + if (p && strncasecmp(p, "yes", 3) == 0) + ret = 1; + if (p) + xfree(p); + if (ret != -1) + return ret; } } @@ -522,7 +478,6 @@ * check whether the supplied host key is valid, return -1 if the key * is not valid. the user_hostfile will not be updated if 'readonly' is true. */ - static int check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key, int readonly, const char *user_hostfile, const char *system_hostfile) @@ -535,7 +490,8 @@ HostStatus ip_status; int local = 0, host_ip_differ = 0; char ntop[NI_MAXHOST]; - int host_line, ip_line; + char msg[1024]; + int len, host_line, ip_line, has_keys; const char *host_file = NULL, *ip_file = NULL; /* @@ -609,7 +565,7 @@ */ host_file = user_hostfile; host_status = check_host_in_hostfile(host_file, host, host_key, - file_key, &host_line); + file_key, &host_line); if (host_status == HOST_NEW) { host_file = system_hostfile; host_status = check_host_in_hostfile(host_file, host, host_key, @@ -652,7 +608,7 @@ "'%.128s' not in list of known hosts.", type, ip); else if (!add_host_to_hostfile(user_hostfile, ip, - host_key)) + host_key)) log("Failed to add the %s host key for IP " "address '%.128s' to the list of known " "hosts (%.30s).", type, ip, user_hostfile); @@ -676,19 +632,22 @@ "have requested strict checking.", type, host); goto fail; } else if (options.strict_host_key_checking == 2) { + has_keys = show_other_keys(host, host_key); /* The default */ - char prompt[1024]; fp = key_fingerprint(host_key, SSH_FP_MD5, SSH_FP_HEX); - snprintf(prompt, sizeof(prompt), + snprintf(msg, sizeof(msg), "The authenticity of host '%.200s (%s)' can't be " - "established.\n" + "established%s\n" "%s key fingerprint is %s.\n" "Are you sure you want to continue connecting " - "(yes/no)? ", host, ip, type, fp); + "(yes/no)? ", + host, ip, + has_keys ? ",\nbut keys of different type are already " + "known for this host." : ".", + type, fp); xfree(fp); - if (!confirm(prompt)) { + if (!confirm(msg)) goto fail; - } } if (options.check_host_ip && ip_status == HOST_NEW) { snprintf(hostline, sizeof(hostline), "%s,%s", host, ip); @@ -778,7 +737,7 @@ error("Port forwarding is disabled to avoid " "man-in-the-middle attacks."); options.num_local_forwards = - options.num_remote_forwards = 0; + options.num_remote_forwards = 0; } /* * XXX Should permit the user to change to use the new id. @@ -788,24 +747,35 @@ * accept the authentication. */ break; + case HOST_FOUND: + fatal("internal error"); + break; } if (options.check_host_ip && host_status != HOST_CHANGED && ip_status == HOST_CHANGED) { - log("Warning: the %s host key for '%.200s' " - "differs from the key for the IP address '%.128s'", - type, host, ip); - if (host_status == HOST_OK) - log("Matching host key in %s:%d", host_file, host_line); - log("Offending key for IP in %s:%d", ip_file, ip_line); + snprintf(msg, sizeof(msg), + "Warning: the %s host key for '%.200s' " + "differs from the key for the IP address '%.128s'" + "\nOffending key for IP in %s:%d", + type, host, ip, ip_file, ip_line); + if (host_status == HOST_OK) { + len = strlen(msg); + snprintf(msg + len, sizeof(msg) - len, + "\nMatching host key in %s:%d", + host_file, host_line); + } if (options.strict_host_key_checking == 1) { + log(msg); error("Exiting, you have requested strict checking."); goto fail; } else if (options.strict_host_key_checking == 2) { - if (!confirm("Are you sure you want " - "to continue connecting (yes/no)? ")) { + strlcat(msg, "\nAre you sure you want " + "to continue connecting (yes/no)? ", sizeof(msg)); + if (!confirm(msg)) goto fail; - } + } else { + log(msg); } } @@ -841,7 +811,7 @@ * This function does not require super-user privileges. */ void -ssh_login(Key **keys, int nkeys, const char *orighost, +ssh_login(Sensitive *sensitive, const char *orighost, struct sockaddr *hostaddr, struct passwd *pw) { char *host, *cp; @@ -866,10 +836,10 @@ /* authenticate user */ if (compat20) { ssh_kex2(host, hostaddr); - ssh_userauth2(local_user, server_user, host, keys, nkeys); + ssh_userauth2(local_user, server_user, host, sensitive); } else { ssh_kex(host, hostaddr); - ssh_userauth1(local_user, server_user, host, keys, nkeys); + ssh_userauth1(local_user, server_user, host, sensitive); } } @@ -890,4 +860,59 @@ packet_put_string(padded, size); memset(padded, 0, size); xfree(padded); +} + +static int +show_key_from_file(const char *file, const char *host, int keytype) +{ + Key *found; + char *fp; + int line, ret; + + found = key_new(keytype); + if ((ret = lookup_key_in_hostfile_by_type(file, host, + keytype, found, &line))) { + fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX); + log("WARNING: %s key found for host %s\n" + "in %s:%d\n" + "%s key fingerprint %s.", + key_type(found), host, file, line, + key_type(found), fp); + xfree(fp); + } + key_free(found); + return (ret); +} + +/* print all known host keys for a given host, but skip keys of given type */ +static int +show_other_keys(const char *host, Key *key) +{ + int type[] = { KEY_RSA1, KEY_RSA, KEY_DSA, -1}; + int i, found = 0; + + for (i = 0; type[i] != -1; i++) { + if (type[i] == key->type) + continue; + if (type[i] != KEY_RSA1 && + show_key_from_file(options.user_hostfile2, host, type[i])) { + found = 1; + continue; + } + if (type[i] != KEY_RSA1 && + show_key_from_file(options.system_hostfile2, host, type[i])) { + found = 1; + continue; + } + if (show_key_from_file(options.user_hostfile, host, type[i])) { + found = 1; + continue; + } + if (show_key_from_file(options.system_hostfile, host, type[i])) { + found = 1; + continue; + } + debug2("no key of type %d for host %s", type[i], host); + } + return (found); }