=================================================================== RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/sshconnect.c,v retrieving revision 1.168 retrieving revision 1.168.2.3 diff -u -r1.168 -r1.168.2.3 --- src/usr.bin/ssh/sshconnect.c 2005/07/17 07:17:55 1.168 +++ src/usr.bin/ssh/sshconnect.c 2006/11/08 00:44:05 1.168.2.3 @@ -1,3 +1,4 @@ +/* $OpenBSD: sshconnect.c,v 1.168.2.3 2006/11/08 00:44:05 brad Exp $ */ /* * Author: Tatu Ylonen * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -12,13 +13,27 @@ * called by a name other than "ssh" or "Secure Shell". */ -#include "includes.h" -RCSID("$OpenBSD: sshconnect.c,v 1.168 2005/07/17 07:17:55 djm Exp $"); +#include +#include +#include +#include +#include -#include +#include -#include "ssh.h" +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + #include "xmalloc.h" +#include "ssh.h" #include "rsa.h" #include "buffer.h" #include "packet.h" @@ -31,13 +46,13 @@ #include "readconf.h" #include "atomicio.h" #include "misc.h" - #include "dns.h" +#include "version.h" char *client_version_string = NULL; char *server_version_string = NULL; -int matching_host_key_dns = 0; +static int matching_host_key_dns = 0; /* import */ extern Options options; @@ -59,7 +74,6 @@ int pin[2], pout[2]; pid_t pid; char strport[NI_MAXSERV]; - size_t len; /* Convert the port number into a string. */ snprintf(strport, sizeof strport, "%hu", port); @@ -71,10 +85,7 @@ * Use "exec" to avoid "sh -c" processes on some platforms * (e.g. Solaris) */ - len = strlen(proxy_command) + 6; - tmp = xmalloc(len); - strlcpy(tmp, "exec ", len); - strlcat(tmp, proxy_command, len); + xasprintf(&tmp, "exec %s", proxy_command); command_string = percent_expand(tmp, "h", host, "p", strport, (char *)NULL); xfree(tmp); @@ -91,8 +102,7 @@ char *argv[10]; /* Child. Permanently give up superuser privileges. */ - seteuid(original_real_uid); - setuid(original_real_uid); + permanently_drop_suid(original_real_uid); /* Redirect stdin and stdout. */ close(pin[1]); @@ -202,7 +212,7 @@ fd_set *fdset; struct timeval tv; socklen_t optlen; - int fdsetsz, optval, rc, result = -1; + int optval, rc, result = -1; if (timeout <= 0) return (connect(sockfd, serv_addr, addrlen)); @@ -216,10 +226,8 @@ if (errno != EINPROGRESS) return (-1); - fdsetsz = howmany(sockfd + 1, NFDBITS) * sizeof(fd_mask); - fdset = (fd_set *)xmalloc(fdsetsz); - - memset(fdset, 0, fdsetsz); + fdset = (fd_set *)xcalloc(howmany(sockfd + 1, NFDBITS), + sizeof(fd_mask)); FD_SET(sockfd, fdset); tv.tv_sec = timeout; tv.tv_usec = 0; @@ -302,17 +310,16 @@ fatal("%s: %.100s: %s", __progname, host, gai_strerror(gaierr)); - /* - * Try to connect several times. On some machines, the first time - * will sometimes fail. In general socket code appears to behave - * quite magically on many machines. - */ - for (attempt = 0; ;) { - if (attempt > 0) + for (attempt = 0; attempt < connection_attempts; attempt++) { + if (attempt > 0) { + /* Sleep a moment before retrying. */ + sleep(1); debug("Trying again..."); - - /* Loop through addresses for this host, and try each one in - sequence until the connection succeeds. */ + } + /* + * Loop through addresses for this host, and try each one in + * sequence until the connection succeeds. + */ for (ai = aitop; ai; ai = ai->ai_next) { if (ai->ai_family != AF_INET && ai->ai_family != AF_INET6) continue; @@ -339,29 +346,18 @@ } else { 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. - */ close(sock); + sock = -1; } } - if (ai) + if (sock != -1) break; /* Successful connection. */ - - attempt++; - if (attempt >= connection_attempts) - break; - /* Sleep a moment before retrying. */ - sleep(1); } freeaddrinfo(aitop); /* Return failure if we didn't get a successful connection. */ - if (attempt >= connection_attempts) { + if (sock == -1) { error("ssh: connect to host %s port %s: %s", host, strport, strerror(errno)); return (-1); @@ -393,10 +389,10 @@ int connection_in = packet_get_connection_in(); int connection_out = packet_get_connection_out(); int minor1 = PROTOCOL_MINOR_1; - u_int i; + u_int i, n; /* Read other side's version identification. */ - for (;;) { + for (n = 0;;) { for (i = 0; i < sizeof(buf) - 1; i++) { size_t len = atomicio(read, connection_in, &buf[i], 1); @@ -413,6 +409,8 @@ 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) @@ -514,13 +512,17 @@ * 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. */ +#define RDRW 0 +#define RDONLY 1 +#define ROQUIET 2 static int -check_host_key(char *host, struct sockaddr *hostaddr, Key *host_key, - int readonly, const char *user_hostfile, const char *system_hostfile) +check_host_key(char *hostname, struct sockaddr *hostaddr, u_short port, + Key *host_key, int readonly, const char *user_hostfile, + const char *system_hostfile) { Key *file_key; const char *type = key_type(host_key); - char *ip = NULL; + char *ip = NULL, *host = NULL; char hostline[1000], *hostp, *fp; HostStatus host_status; HostStatus ip_status; @@ -567,7 +569,7 @@ if (getnameinfo(hostaddr, hostaddr->sa_len, ntop, sizeof(ntop), NULL, 0, NI_NUMERICHOST) != 0) fatal("check_host_key: getnameinfo failed"); - ip = xstrdup(ntop); + ip = put_host_port(ntop, port); } else { ip = xstrdup(""); } @@ -575,18 +577,21 @@ * Turn off check_host_ip if the connection is to localhost, via proxy * command or if we don't have a hostname to compare with */ - if (options.check_host_ip && - (local || strcmp(host, ip) == 0 || options.proxy_command != NULL)) + if (options.check_host_ip && (local || + strcmp(hostname, ip) == 0 || options.proxy_command != NULL)) options.check_host_ip = 0; /* - * Allow the user to record the key under a different name. This is - * useful for ssh tunneling over forwarded connections or if you run - * multiple sshd's on different ports on the same machine. + * Allow the user to record the key under a different name or + * differentiate a non-standard port. This is useful for ssh + * tunneling over forwarded connections or if you run multiple + * sshd's on different ports on the same machine. */ if (options.host_key_alias != NULL) { - host = options.host_key_alias; + host = xstrdup(options.host_key_alias); debug("using hostkeyalias: %s", host); + } else { + host = put_host_port(hostname, port); } /* @@ -596,7 +601,7 @@ file_key = key_new(host_key->type); /* - * Check if the host key is present in the user\'s list of known + * Check if the host key is present in the user's list of known * hosts or in the systemwide list. */ host_file = user_hostfile; @@ -655,6 +660,15 @@ } break; case HOST_NEW: + if (options.host_key_alias == NULL && port != 0 && + port != SSH_DEFAULT_PORT) { + debug("checking without port identifier"); + if (check_host_key(hostname, hostaddr, 0, host_key, 2, + user_hostfile, system_hostfile) == 0) { + debug("found matching key w/out port"); + break; + } + } if (readonly) goto fail; /* The host is new. */ @@ -734,6 +748,8 @@ "list of known hosts.", hostp, type); break; case HOST_CHANGED: + if (readonly == ROQUIET) + goto fail; if (options.check_host_ip && host_ip_differ) { char *key_msg; if (ip_status == HOST_NEW) @@ -772,7 +788,7 @@ /* * If strict host key checking has not been requested, allow * the connection but without MITM-able authentication or - * agent forwarding. + * forwarding. */ if (options.password_authentication) { error("Password authentication is disabled to avoid " @@ -807,6 +823,11 @@ options.num_local_forwards = options.num_remote_forwards = 0; } + if (options.tun_open != SSH_TUNMODE_NO) { + error("Tunnel forwarding is disabled to avoid " + "man-in-the-middle attacks."); + options.tun_open = SSH_TUNMODE_NO; + } /* * XXX Should permit the user to change to use the new id. * This could be done by converting the host key to an @@ -848,10 +869,12 @@ } xfree(ip); + xfree(host); return 0; fail: xfree(ip); + xfree(host); return -1; } @@ -885,12 +908,13 @@ /* return ok if the key can be found in an old keyfile */ if (stat(options.system_hostfile2, &st) == 0 || stat(options.user_hostfile2, &st) == 0) { - if (check_host_key(host, hostaddr, host_key, /*readonly*/ 1, - options.user_hostfile2, options.system_hostfile2) == 0) + if (check_host_key(host, hostaddr, options.port, host_key, + RDONLY, options.user_hostfile2, + options.system_hostfile2) == 0) return 0; } - return check_host_key(host, hostaddr, host_key, /*readonly*/ 0, - options.user_hostfile, options.system_hostfile); + return check_host_key(host, hostaddr, options.port, host_key, + RDRW, options.user_hostfile, options.system_hostfile); } /* @@ -914,7 +938,7 @@ host = xstrdup(orighost); for (cp = host; *cp; cp++) if (isupper(*cp)) - *cp = tolower(*cp); + *cp = (char)tolower(*cp); /* Exchange protocol version identification strings with the server. */ ssh_exchange_identification(); @@ -931,6 +955,7 @@ ssh_kex(host, hostaddr); ssh_userauth1(local_user, server_user, host, sensitive); } + xfree(local_user); } void @@ -944,8 +969,7 @@ return; } size = roundup(strlen(password) + 1, 32); - padded = xmalloc(size); - memset(padded, 0, size); + padded = xcalloc(1, size); strlcpy(padded, password, size); packet_put_string(padded, size); memset(padded, 0, size); @@ -1026,4 +1050,40 @@ error("Please contact your system administrator."); xfree(fp); +} + +/* + * Execute a local command + */ +int +ssh_local_cmd(const char *args) +{ + char *shell; + pid_t pid; + int status; + + if (!options.permit_local_command || + args == NULL || !*args) + return (1); + + if ((shell = getenv("SHELL")) == NULL) + shell = _PATH_BSHELL; + + pid = fork(); + if (pid == 0) { + debug3("Executing %s -c \"%s\"", shell, args); + execl(shell, shell, "-c", args, (char *)NULL); + error("Couldn't execute %s -c \"%s\": %s", + shell, args, strerror(errno)); + _exit(1); + } else if (pid == -1) + fatal("fork failed: %.100s", strerror(errno)); + while (waitpid(pid, &status, 0) == -1) + if (errno != EINTR) + fatal("Couldn't wait for child: %s", strerror(errno)); + + if (!WIFEXITED(status)) + return (1); + + return (WEXITSTATUS(status)); }