From 133a7928464fee64fe0d69177d1837ade4d4e8d9 Mon Sep 17 00:00:00 2001 From: markus Date: Tue, 28 Mar 2000 21:15:45 +0000 Subject: [PATCH] split sshd.c -> auth.c session.c sshd.c plus cleanup and goto-removal --- usr.bin/ssh/auth.c | 554 ++++++++++++ usr.bin/ssh/auth.h | 6 + usr.bin/ssh/session.c | 1085 +++++++++++++++++++++++ usr.bin/ssh/session.h | 7 + usr.bin/ssh/sshd.c | 1725 +++---------------------------------- usr.bin/ssh/sshd/Makefile | 3 +- 6 files changed, 1755 insertions(+), 1625 deletions(-) create mode 100644 usr.bin/ssh/auth.c create mode 100644 usr.bin/ssh/auth.h create mode 100644 usr.bin/ssh/session.c create mode 100644 usr.bin/ssh/session.h diff --git a/usr.bin/ssh/auth.c b/usr.bin/ssh/auth.c new file mode 100644 index 00000000000..6fc799e08ce --- /dev/null +++ b/usr.bin/ssh/auth.c @@ -0,0 +1,554 @@ +/* + * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland + * All rights reserved + */ + +#include "includes.h" +RCSID("$OpenBSD: auth.c,v 1.1 2000/03/28 21:15:45 markus Exp $"); + +#include "xmalloc.h" +#include "rsa.h" +#include "ssh.h" +#include "pty.h" +#include "packet.h" +#include "buffer.h" +#include "cipher.h" +#include "mpaux.h" +#include "servconf.h" +#include "channels.h" +#include "match.h" + +#include "session.h" +#include "dispatch.h" + +/* import */ +extern ServerOptions options; +extern char *forced_command; + +/* + * Check if the user is allowed to log in via ssh. If user is listed in + * DenyUsers or user's primary group is listed in DenyGroups, false will + * be returned. If AllowUsers isn't empty and user isn't listed there, or + * if AllowGroups isn't empty and user isn't listed there, false will be + * returned. + * If the user's shell is not executable, false will be returned. + * Otherwise true is returned. + */ +static int +allowed_user(struct passwd * pw) +{ + struct stat st; + struct group *grp; + int i; + + /* Shouldn't be called if pw is NULL, but better safe than sorry... */ + if (!pw) + return 0; + + /* deny if shell does not exists or is not executable */ + if (stat(pw->pw_shell, &st) != 0) + return 0; + if (!((st.st_mode & S_IFREG) && (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)))) + return 0; + + /* Return false if user is listed in DenyUsers */ + if (options.num_deny_users > 0) { + if (!pw->pw_name) + return 0; + for (i = 0; i < options.num_deny_users; i++) + if (match_pattern(pw->pw_name, options.deny_users[i])) + return 0; + } + /* Return false if AllowUsers isn't empty and user isn't listed there */ + if (options.num_allow_users > 0) { + if (!pw->pw_name) + return 0; + for (i = 0; i < options.num_allow_users; i++) + if (match_pattern(pw->pw_name, options.allow_users[i])) + break; + /* i < options.num_allow_users iff we break for loop */ + if (i >= options.num_allow_users) + return 0; + } + /* Get the primary group name if we need it. Return false if it fails */ + if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { + grp = getgrgid(pw->pw_gid); + if (!grp) + return 0; + + /* Return false if user's group is listed in DenyGroups */ + if (options.num_deny_groups > 0) { + if (!grp->gr_name) + return 0; + for (i = 0; i < options.num_deny_groups; i++) + if (match_pattern(grp->gr_name, options.deny_groups[i])) + return 0; + } + /* + * Return false if AllowGroups isn't empty and user's group + * isn't listed there + */ + if (options.num_allow_groups > 0) { + if (!grp->gr_name) + return 0; + for (i = 0; i < options.num_allow_groups; i++) + if (match_pattern(grp->gr_name, options.allow_groups[i])) + break; + /* i < options.num_allow_groups iff we break for + loop */ + if (i >= options.num_allow_groups) + return 0; + } + } + /* We found no reason not to let this user try to log on... */ + return 1; +} + +/* + * convert ssh auth msg type into description + */ +char * +get_authname(int type) +{ + static char buf[1024]; + switch (type) { + case SSH_CMSG_AUTH_PASSWORD: + return "password"; + case SSH_CMSG_AUTH_RSA: + return "rsa"; + case SSH_CMSG_AUTH_RHOSTS_RSA: + return "rhosts-rsa"; + case SSH_CMSG_AUTH_RHOSTS: + return "rhosts"; +#ifdef KRB4 + case SSH_CMSG_AUTH_KERBEROS: + return "kerberos"; +#endif +#ifdef SKEY + case SSH_CMSG_AUTH_TIS_RESPONSE: + return "s/key"; +#endif + } + snprintf(buf, sizeof buf, "bad-auth-msg-%d", type); + return buf; +} + +#define AUTH_FAIL_MAX 6 +#define AUTH_FAIL_LOG (AUTH_FAIL_MAX/2) +#define AUTH_FAIL_MSG "Too many authentication failures for %.100s" + +/* + * The user does not exist or access is denied, + * but fake indication that authentication is needed. + */ +void +do_fake_authloop1(char *user) +{ + int attempt = 0; + + log("Faking authloop for illegal user %.200s from %.200s port %d", + user, + get_remote_ipaddr(), + get_remote_port()); + + /* Indicate that authentication is needed. */ + packet_start(SSH_SMSG_FAILURE); + packet_send(); + packet_write_wait(); + + /* + * Keep reading packets, and always respond with a failure. This is + * to avoid disclosing whether such a user really exists. + */ + for (attempt = 1;; attempt++) { + /* Read a packet. This will not return if the client disconnects. */ + int plen; + int type = packet_read(&plen); +#ifdef SKEY + unsigned int dlen; + char *password, *skeyinfo; + password = NULL; + /* Try to send a fake s/key challenge. */ + if (options.skey_authentication == 1 && + (skeyinfo = skey_fake_keyinfo(user)) != NULL) { + if (type == SSH_CMSG_AUTH_TIS) { + packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); + packet_put_string(skeyinfo, strlen(skeyinfo)); + packet_send(); + packet_write_wait(); + continue; + } else if (type == SSH_CMSG_AUTH_PASSWORD && + options.password_authentication && + (password = packet_get_string(&dlen)) != NULL && + dlen == 5 && + strncasecmp(password, "s/key", 5) == 0 ) { + packet_send_debug(skeyinfo); + } + } + if (password != NULL) + xfree(password); +#endif + if (attempt > AUTH_FAIL_MAX) + packet_disconnect(AUTH_FAIL_MSG, user); + + /* + * Send failure. This should be indistinguishable from a + * failed authentication. + */ + packet_start(SSH_SMSG_FAILURE); + packet_send(); + packet_write_wait(); + } + /* NOTREACHED */ + abort(); +} + +/* + * read packets and try to authenticate local user *pw. + * return if authentication is successfull + */ +void +do_authloop(struct passwd * pw) +{ + int attempt = 0; + unsigned int bits; + RSA *client_host_key; + BIGNUM *n; + char *client_user, *password; + char user[1024]; + unsigned int dlen; + int plen, nlen, elen; + unsigned int ulen; + int type = 0; + void (*authlog) (const char *fmt,...) = verbose; + + /* Indicate that authentication is needed. */ + packet_start(SSH_SMSG_FAILURE); + packet_send(); + packet_write_wait(); + + for (attempt = 1;; attempt++) { + int authenticated = 0; + strlcpy(user, "", sizeof user); + + /* Get a packet from the client. */ + type = packet_read(&plen); + + /* Process the packet. */ + switch (type) { +#ifdef AFS + case SSH_CMSG_HAVE_KERBEROS_TGT: + if (!options.kerberos_tgt_passing) { + /* packet_get_all(); */ + verbose("Kerberos tgt passing disabled."); + break; + } else { + /* Accept Kerberos tgt. */ + char *tgt = packet_get_string(&dlen); + packet_integrity_check(plen, 4 + dlen, type); + if (!auth_kerberos_tgt(pw, tgt)) + verbose("Kerberos tgt REFUSED for %s", pw->pw_name); + xfree(tgt); + } + continue; + + case SSH_CMSG_HAVE_AFS_TOKEN: + if (!options.afs_token_passing || !k_hasafs()) { + /* packet_get_all(); */ + verbose("AFS token passing disabled."); + break; + } else { + /* Accept AFS token. */ + char *token_string = packet_get_string(&dlen); + packet_integrity_check(plen, 4 + dlen, type); + if (!auth_afs_token(pw, token_string)) + verbose("AFS token REFUSED for %s", pw->pw_name); + xfree(token_string); + } + continue; +#endif /* AFS */ +#ifdef KRB4 + case SSH_CMSG_AUTH_KERBEROS: + if (!options.kerberos_authentication) { + /* packet_get_all(); */ + verbose("Kerberos authentication disabled."); + break; + } else { + /* Try Kerberos v4 authentication. */ + KTEXT_ST auth; + char *tkt_user = NULL; + char *kdata = packet_get_string((unsigned int *) &auth.length); + packet_integrity_check(plen, 4 + auth.length, type); + + if (auth.length < MAX_KTXT_LEN) + memcpy(auth.dat, kdata, auth.length); + xfree(kdata); + + authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user); + + if (authenticated) { + snprintf(user, sizeof user, " tktuser %s", tkt_user); + xfree(tkt_user); + } + } + break; +#endif /* KRB4 */ + + case SSH_CMSG_AUTH_RHOSTS: + if (!options.rhosts_authentication) { + verbose("Rhosts authentication disabled."); + break; + } + /* + * Get client user name. Note that we just have to + * trust the client; this is one reason why rhosts + * authentication is insecure. (Another is + * IP-spoofing on a local network.) + */ + client_user = packet_get_string(&ulen); + packet_integrity_check(plen, 4 + ulen, type); + + /* Try to authenticate using /etc/hosts.equiv and + .rhosts. */ + authenticated = auth_rhosts(pw, client_user); + + snprintf(user, sizeof user, " ruser %s", client_user); + xfree(client_user); + break; + + case SSH_CMSG_AUTH_RHOSTS_RSA: + if (!options.rhosts_rsa_authentication) { + verbose("Rhosts with RSA authentication disabled."); + break; + } + /* + * Get client user name. Note that we just have to + * trust the client; root on the client machine can + * claim to be any user. + */ + client_user = packet_get_string(&ulen); + + /* Get the client host key. */ + client_host_key = RSA_new(); + if (client_host_key == NULL) + fatal("RSA_new failed"); + client_host_key->e = BN_new(); + client_host_key->n = BN_new(); + if (client_host_key->e == NULL || client_host_key->n == NULL) + fatal("BN_new failed"); + bits = packet_get_int(); + packet_get_bignum(client_host_key->e, &elen); + packet_get_bignum(client_host_key->n, &nlen); + + if (bits != BN_num_bits(client_host_key->n)) + error("Warning: keysize mismatch for client_host_key: " + "actual %d, announced %d", BN_num_bits(client_host_key->n), bits); + packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type); + + authenticated = auth_rhosts_rsa(pw, client_user, client_host_key); + RSA_free(client_host_key); + + snprintf(user, sizeof user, " ruser %s", client_user); + xfree(client_user); + break; + + case SSH_CMSG_AUTH_RSA: + if (!options.rsa_authentication) { + verbose("RSA authentication disabled."); + break; + } + /* RSA authentication requested. */ + n = BN_new(); + packet_get_bignum(n, &nlen); + packet_integrity_check(plen, nlen, type); + authenticated = auth_rsa(pw, n); + BN_clear_free(n); + break; + + case SSH_CMSG_AUTH_PASSWORD: + if (!options.password_authentication) { + verbose("Password authentication disabled."); + break; + } + /* + * Read user password. It is in plain text, but was + * transmitted over the encrypted channel so it is + * not visible to an outside observer. + */ + password = packet_get_string(&dlen); + packet_integrity_check(plen, 4 + dlen, type); + + /* Try authentication with the password. */ + authenticated = auth_password(pw, password); + + memset(password, 0, strlen(password)); + xfree(password); + break; + +#ifdef SKEY + case SSH_CMSG_AUTH_TIS: + debug("rcvd SSH_CMSG_AUTH_TIS"); + if (options.skey_authentication == 1) { + char *skeyinfo = skey_keyinfo(pw->pw_name); + if (skeyinfo == NULL) { + debug("generating fake skeyinfo for %.100s.", pw->pw_name); + skeyinfo = skey_fake_keyinfo(pw->pw_name); + } + if (skeyinfo != NULL) { + /* we send our s/key- in tis-challenge messages */ + debug("sending challenge '%s'", skeyinfo); + packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); + packet_put_string(skeyinfo, strlen(skeyinfo)); + packet_send(); + packet_write_wait(); + continue; + } + } + break; + case SSH_CMSG_AUTH_TIS_RESPONSE: + debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE"); + if (options.skey_authentication == 1) { + char *response = packet_get_string(&dlen); + debug("skey response == '%s'", response); + packet_integrity_check(plen, 4 + dlen, type); + authenticated = (skey_haskey(pw->pw_name) == 0 && + skey_passcheck(pw->pw_name, response) != -1); + xfree(response); + } + break; +#else + case SSH_CMSG_AUTH_TIS: + /* TIS Authentication is unsupported */ + log("TIS authentication unsupported."); + break; +#endif + + default: + /* + * Any unknown messages will be ignored (and failure + * returned) during authentication. + */ + log("Unknown message during authentication: type %d", type); + break; + } + + /* + * Check if the user is logging in as root and root logins + * are disallowed. + * Note that root login is allowed for forced commands. + */ + if (authenticated && pw->pw_uid == 0 && !options.permit_root_login) { + if (forced_command) { + log("Root login accepted for forced command."); + } else { + authenticated = 0; + log("ROOT LOGIN REFUSED FROM %.200s", + get_canonical_hostname()); + } + } + + /* Raise logging level */ + if (authenticated || + attempt == AUTH_FAIL_LOG || + type == SSH_CMSG_AUTH_PASSWORD) + authlog = log; + + authlog("%s %s for %.200s from %.200s port %d%s", + authenticated ? "Accepted" : "Failed", + get_authname(type), + pw->pw_uid == 0 ? "ROOT" : pw->pw_name, + get_remote_ipaddr(), + get_remote_port(), + user); + + if (authenticated) + return; + + if (attempt > AUTH_FAIL_MAX) + packet_disconnect(AUTH_FAIL_MSG, pw->pw_name); + + /* Send a message indicating that the authentication attempt failed. */ + packet_start(SSH_SMSG_FAILURE); + packet_send(); + packet_write_wait(); + } +} + +/* + * Performs authentication of an incoming connection. Session key has already + * been exchanged and encryption is enabled. + */ +void +do_authentication() +{ + struct passwd *pw, pwcopy; + int plen; + unsigned int ulen; + char *user; + + /* Get the name of the user that we wish to log in as. */ + packet_read_expect(&plen, SSH_CMSG_USER); + + /* Get the user name. */ + user = packet_get_string(&ulen); + packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER); + + setproctitle("%s", user); + +#ifdef AFS + /* If machine has AFS, set process authentication group. */ + if (k_hasafs()) { + k_setpag(); + k_unlog(); + } +#endif /* AFS */ + + /* Verify that the user is a valid user. */ + pw = getpwnam(user); + if (!pw || !allowed_user(pw)) + do_fake_authloop1(user); + xfree(user); + + /* Take a copy of the returned structure. */ + memset(&pwcopy, 0, sizeof(pwcopy)); + pwcopy.pw_name = xstrdup(pw->pw_name); + pwcopy.pw_passwd = xstrdup(pw->pw_passwd); + pwcopy.pw_uid = pw->pw_uid; + pwcopy.pw_gid = pw->pw_gid; + pwcopy.pw_dir = xstrdup(pw->pw_dir); + pwcopy.pw_shell = xstrdup(pw->pw_shell); + pw = &pwcopy; + + /* + * If we are not running as root, the user must have the same uid as + * the server. + */ + if (getuid() != 0 && pw->pw_uid != getuid()) + packet_disconnect("Cannot change user when server not running as root."); + + debug("Attempting authentication for %.100s.", pw->pw_name); + + /* If the user has no password, accept authentication immediately. */ + if (options.password_authentication && +#ifdef KRB4 + (!options.kerberos_authentication || options.kerberos_or_local_passwd) && +#endif /* KRB4 */ + auth_password(pw, "")) { + /* Authentication with empty password succeeded. */ + log("Login for user %s from %.100s, accepted without authentication.", + pw->pw_name, get_remote_ipaddr()); + } else { + /* Loop until the user has been authenticated or the + connection is closed, do_authloop() returns only if + authentication is successfull */ + do_authloop(pw); + } + + /* The user has been authenticated and accepted. */ + packet_start(SSH_SMSG_SUCCESS); + packet_send(); + packet_write_wait(); + + /* Perform session preparation. */ + do_authenticated(pw); +} diff --git a/usr.bin/ssh/auth.h b/usr.bin/ssh/auth.h new file mode 100644 index 00000000000..805177723ed --- /dev/null +++ b/usr.bin/ssh/auth.h @@ -0,0 +1,6 @@ +#ifndef AUTH_H +#define AUTH_H + +void do_authentication(void); + +#endif diff --git a/usr.bin/ssh/session.c b/usr.bin/ssh/session.c new file mode 100644 index 00000000000..2e486a3764d --- /dev/null +++ b/usr.bin/ssh/session.c @@ -0,0 +1,1085 @@ +/* + * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland + * All rights reserved + */ + +#include "includes.h" +RCSID("$OpenBSD: session.c,v 1.1 2000/03/28 21:15:45 markus Exp $"); + +#include "xmalloc.h" +#include "ssh.h" +#include "pty.h" +#include "packet.h" +#include "buffer.h" +#include "cipher.h" +#include "mpaux.h" +#include "servconf.h" +#include "uidswap.h" +#include "compat.h" +#include "channels.h" +#include "nchan.h" + +/* types */ + +#define TTYSZ 64 +typedef struct Session Session; +struct Session { + int used; + int self; + struct passwd *pw; + pid_t pid; + /* tty */ + char *term; + int ptyfd, ttyfd, ptymaster; + int row, col, xpixel, ypixel; + char tty[TTYSZ]; + /* X11 */ + char *display; + int screen; + char *auth_proto; + char *auth_data; + /* proto 2 */ + int chanid; +}; + +/* func */ + +Session *session_new(void); +void session_set_fds(Session *s, int fdin, int fdout, int fderr); +void session_pty_cleanup(Session *s); +void do_exec_pty(Session *s, const char *command, struct passwd * pw); +void do_exec_no_pty(Session *s, const char *command, struct passwd * pw); + +void +do_child(const char *command, struct passwd * pw, const char *term, + const char *display, const char *auth_proto, + const char *auth_data, const char *ttyname); + +/* import */ +extern ServerOptions options; +extern char *__progname; +extern int log_stderr; +extern int debug_flag; + +/* Local Xauthority file. */ +static char *xauthfile; + +/* data */ +#define MAX_SESSIONS 10 +Session sessions[MAX_SESSIONS]; + +/* Flags set in auth-rsa from authorized_keys flags. These are set in auth-rsa.c. */ +int no_port_forwarding_flag = 0; +int no_agent_forwarding_flag = 0; +int no_x11_forwarding_flag = 0; +int no_pty_flag = 0; + +/* RSA authentication "command=" option. */ +char *forced_command = NULL; + +/* RSA authentication "environment=" options. */ +struct envstring *custom_environment = NULL; + +/* + * Remove local Xauthority file. + */ +void +xauthfile_cleanup_proc(void *ignore) +{ + debug("xauthfile_cleanup_proc called"); + + if (xauthfile != NULL) { + char *p; + unlink(xauthfile); + p = strrchr(xauthfile, '/'); + if (p != NULL) { + *p = '\0'; + rmdir(xauthfile); + } + xfree(xauthfile); + xauthfile = NULL; + } +} + +/* + * Function to perform cleanup if we get aborted abnormally (e.g., due to a + * dropped connection). + */ +void +pty_cleanup_proc(void *session) +{ + Session *s=session; + if (s == NULL) + fatal("pty_cleanup_proc: no session"); + debug("pty_cleanup_proc: %s", s->tty); + + if (s->pid != 0) { + /* Record that the user has logged out. */ + record_logout(s->pid, s->tty); + } + + /* Release the pseudo-tty. */ + pty_release(s->tty); +} + +/* + * Prepares for an interactive session. This is called after the user has + * been successfully authenticated. During this message exchange, pseudo + * terminals are allocated, X11, TCP/IP, and authentication agent forwardings + * are requested, etc. + */ +void +do_authenticated(struct passwd * pw) +{ + Session *s; + int type; + int compression_level = 0, enable_compression_after_reply = 0; + int have_pty = 0; + char *command; + int n_bytes; + int plen; + unsigned int proto_len, data_len, dlen; + + /* + * Cancel the alarm we set to limit the time taken for + * authentication. + */ + alarm(0); + + /* + * Inform the channel mechanism that we are the server side and that + * the client may request to connect to any port at all. (The user + * could do it anyway, and we wouldn\'t know what is permitted except + * by the client telling us, so we can equally well trust the client + * not to request anything bogus.) + */ + if (!no_port_forwarding_flag) + channel_permit_all_opens(); + + s = session_new(); + + /* + * We stay in this loop until the client requests to execute a shell + * or a command. + */ + for (;;) { + int success = 0; + + /* Get a packet from the client. */ + type = packet_read(&plen); + + /* Process the packet. */ + switch (type) { + case SSH_CMSG_REQUEST_COMPRESSION: + packet_integrity_check(plen, 4, type); + compression_level = packet_get_int(); + if (compression_level < 1 || compression_level > 9) { + packet_send_debug("Received illegal compression level %d.", + compression_level); + break; + } + /* Enable compression after we have responded with SUCCESS. */ + enable_compression_after_reply = 1; + success = 1; + break; + + case SSH_CMSG_REQUEST_PTY: + if (no_pty_flag) { + debug("Allocating a pty not permitted for this authentication."); + break; + } + if (have_pty) + packet_disconnect("Protocol error: you already have a pty."); + + debug("Allocating pty."); + + /* Allocate a pty and open it. */ + if (!pty_allocate(&s->ptyfd, &s->ttyfd, s->tty, + sizeof(s->tty))) { + error("Failed to allocate pty."); + break; + } + fatal_add_cleanup(pty_cleanup_proc, (void *)s); + pty_setowner(pw, s->tty); + + /* Get TERM from the packet. Note that the value may be of arbitrary length. */ + s->term = packet_get_string(&dlen); + packet_integrity_check(dlen, strlen(s->term), type); + /* packet_integrity_check(plen, 4 + dlen + 4*4 + n_bytes, type); */ + /* Remaining bytes */ + n_bytes = plen - (4 + dlen + 4 * 4); + + if (strcmp(s->term, "") == 0) { + xfree(s->term); + s->term = NULL; + } + /* Get window size from the packet. */ + s->row = packet_get_int(); + s->col = packet_get_int(); + s->xpixel = packet_get_int(); + s->ypixel = packet_get_int(); + pty_change_window_size(s->ptyfd, s->row, s->col, s->xpixel, s->ypixel); + + /* Get tty modes from the packet. */ + tty_parse_modes(s->ttyfd, &n_bytes); + packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type); + + /* Indicate that we now have a pty. */ + success = 1; + have_pty = 1; + break; + + case SSH_CMSG_X11_REQUEST_FORWARDING: + if (!options.x11_forwarding) { + packet_send_debug("X11 forwarding disabled in server configuration file."); + break; + } +#ifdef XAUTH_PATH + if (no_x11_forwarding_flag) { + packet_send_debug("X11 forwarding not permitted for this authentication."); + break; + } + debug("Received request for X11 forwarding with auth spoofing."); + if (s->display != NULL) + packet_disconnect("Protocol error: X11 display already set."); + + s->auth_proto = packet_get_string(&proto_len); + s->auth_data = packet_get_string(&data_len); + packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type); + + if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER) + s->screen = packet_get_int(); + else + s->screen = 0; + s->display = x11_create_display_inet(s->screen, options.x11_display_offset); + + if (s->display == NULL) + break; + + /* Setup to always have a local .Xauthority. */ + xauthfile = xmalloc(MAXPATHLEN); + strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN); + temporarily_use_uid(pw->pw_uid); + if (mkdtemp(xauthfile) == NULL) { + restore_uid(); + error("private X11 dir: mkdtemp %s failed: %s", + xauthfile, strerror(errno)); + xfree(xauthfile); + xauthfile = NULL; + break; + } + strlcat(xauthfile, "/cookies", MAXPATHLEN); + open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600); + restore_uid(); + fatal_add_cleanup(xauthfile_cleanup_proc, NULL); + success = 1; + break; +#else /* XAUTH_PATH */ + packet_send_debug("No xauth program; cannot forward with spoofing."); + break; +#endif /* XAUTH_PATH */ + + case SSH_CMSG_AGENT_REQUEST_FORWARDING: + if (no_agent_forwarding_flag || compat13) { + debug("Authentication agent forwarding not permitted for this authentication."); + break; + } + debug("Received authentication agent forwarding request."); + auth_input_request_forwarding(pw); + success = 1; + break; + + case SSH_CMSG_PORT_FORWARD_REQUEST: + if (no_port_forwarding_flag) { + debug("Port forwarding not permitted for this authentication."); + break; + } + debug("Received TCP/IP port forwarding request."); + channel_input_port_forward_request(pw->pw_uid == 0); + success = 1; + break; + + case SSH_CMSG_MAX_PACKET_SIZE: + if (packet_set_maxsize(packet_get_int()) > 0) + success = 1; + break; + + case SSH_CMSG_EXEC_SHELL: + case SSH_CMSG_EXEC_CMD: + /* Set interactive/non-interactive mode. */ + packet_set_interactive(have_pty || s->display != NULL, + options.keepalives); + + if (type == SSH_CMSG_EXEC_CMD) { + command = packet_get_string(&dlen); + debug("Exec command '%.500s'", command); + packet_integrity_check(plen, 4 + dlen, type); + } else { + command = NULL; + packet_integrity_check(plen, 0, type); + } + if (forced_command != NULL) { + command = forced_command; + debug("Forced command '%.500s'", forced_command); + } + if (have_pty) + do_exec_pty(s, command, pw); + else + do_exec_no_pty(s, command, pw); + + if (command != NULL) + xfree(command); + /* Cleanup user's local Xauthority file. */ + if (xauthfile) + xauthfile_cleanup_proc(NULL); + return; + + default: + /* + * Any unknown messages in this phase are ignored, + * and a failure message is returned. + */ + log("Unknown packet type received after authentication: %d", type); + } + packet_start(success ? SSH_SMSG_SUCCESS : SSH_SMSG_FAILURE); + packet_send(); + packet_write_wait(); + + /* Enable compression now that we have replied if appropriate. */ + if (enable_compression_after_reply) { + enable_compression_after_reply = 0; + packet_start_compression(compression_level); + } + } +} + +/* + * This is called to fork and execute a command when we have no tty. This + * will call do_child from the child, and server_loop from the parent after + * setting up file descriptors and such. + */ +void +do_exec_no_pty(Session *s, const char *command, struct passwd * pw) +{ + int pid; + +#ifdef USE_PIPES + int pin[2], pout[2], perr[2]; + /* Allocate pipes for communicating with the program. */ + if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0) + packet_disconnect("Could not create pipes: %.100s", + strerror(errno)); +#else /* USE_PIPES */ + int inout[2], err[2]; + /* Uses socket pairs to communicate with the program. */ + if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 || + socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) + packet_disconnect("Could not create socket pairs: %.100s", + strerror(errno)); +#endif /* USE_PIPES */ + if (s == NULL) + fatal("do_exec_no_pty: no session"); + + setproctitle("%s@notty", pw->pw_name); + + /* Fork the child. */ + if ((pid = fork()) == 0) { + /* Child. Reinitialize the log since the pid has changed. */ + log_init(__progname, options.log_level, options.log_facility, log_stderr); + + /* + * Create a new session and process group since the 4.4BSD + * setlogin() affects the entire process group. + */ + if (setsid() < 0) + error("setsid failed: %.100s", strerror(errno)); + +#ifdef USE_PIPES + /* + * Redirect stdin. We close the parent side of the socket + * pair, and make the child side the standard input. + */ + close(pin[1]); + if (dup2(pin[0], 0) < 0) + perror("dup2 stdin"); + close(pin[0]); + + /* Redirect stdout. */ + close(pout[0]); + if (dup2(pout[1], 1) < 0) + perror("dup2 stdout"); + close(pout[1]); + + /* Redirect stderr. */ + close(perr[0]); + if (dup2(perr[1], 2) < 0) + perror("dup2 stderr"); + close(perr[1]); +#else /* USE_PIPES */ + /* + * Redirect stdin, stdout, and stderr. Stdin and stdout will + * use the same socket, as some programs (particularly rdist) + * seem to depend on it. + */ + close(inout[1]); + close(err[1]); + if (dup2(inout[0], 0) < 0) /* stdin */ + perror("dup2 stdin"); + if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */ + perror("dup2 stdout"); + if (dup2(err[0], 2) < 0) /* stderr */ + perror("dup2 stderr"); +#endif /* USE_PIPES */ + + /* Do processing for the child (exec command etc). */ + do_child(command, pw, NULL, s->display, s->auth_proto, s->auth_data, NULL); + /* NOTREACHED */ + } + if (pid < 0) + packet_disconnect("fork failed: %.100s", strerror(errno)); + s->pid = pid; +#ifdef USE_PIPES + /* We are the parent. Close the child sides of the pipes. */ + close(pin[0]); + close(pout[1]); + close(perr[1]); + + /* Enter the interactive session. */ + server_loop(pid, pin[1], pout[0], perr[0]); + /* server_loop has closed pin[1], pout[1], and perr[1]. */ +#else /* USE_PIPES */ + /* We are the parent. Close the child sides of the socket pairs. */ + close(inout[0]); + close(err[0]); + + /* + * Enter the interactive session. Note: server_loop must be able to + * handle the case that fdin and fdout are the same. + */ + server_loop(pid, inout[1], inout[1], err[1]); + /* server_loop has closed inout[1] and err[1]. */ +#endif /* USE_PIPES */ +} + +/* + * This is called to fork and execute a command when we have a tty. This + * will call do_child from the child, and server_loop from the parent after + * setting up file descriptors, controlling tty, updating wtmp, utmp, + * lastlog, and other such operations. + */ +void +do_exec_pty(Session *s, const char *command, struct passwd * pw) +{ + FILE *f; + char buf[100], *time_string; + char line[256]; + const char *hostname; + int fdout, ptyfd, ttyfd, ptymaster; + int quiet_login; + pid_t pid; + socklen_t fromlen; + struct sockaddr_storage from; + struct stat st; + time_t last_login_time; + + if (s == NULL) + fatal("do_exec_pty: no session"); + ptyfd = s->ptyfd; + ttyfd = s->ttyfd; + + /* Get remote host name. */ + hostname = get_canonical_hostname(); + + /* + * Get the time when the user last logged in. Buf will be set to + * contain the hostname the last login was from. + */ + if (!options.use_login) { + last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name, + buf, sizeof(buf)); + } + setproctitle("%s@%s", pw->pw_name, strrchr(s->tty, '/') + 1); + + /* Fork the child. */ + if ((pid = fork()) == 0) { + pid = getpid(); + + /* Child. Reinitialize the log because the pid has + changed. */ + log_init(__progname, options.log_level, options.log_facility, log_stderr); + + /* Close the master side of the pseudo tty. */ + close(ptyfd); + + /* Make the pseudo tty our controlling tty. */ + pty_make_controlling_tty(&ttyfd, s->tty); + + /* Redirect stdin from the pseudo tty. */ + if (dup2(ttyfd, fileno(stdin)) < 0) + error("dup2 stdin failed: %.100s", strerror(errno)); + + /* Redirect stdout to the pseudo tty. */ + if (dup2(ttyfd, fileno(stdout)) < 0) + error("dup2 stdin failed: %.100s", strerror(errno)); + + /* Redirect stderr to the pseudo tty. */ + if (dup2(ttyfd, fileno(stderr)) < 0) + error("dup2 stdin failed: %.100s", strerror(errno)); + + /* Close the extra descriptor for the pseudo tty. */ + close(ttyfd); + +///XXXX ? move to do_child() ?? + /* + * Get IP address of client. This is needed because we want + * to record where the user logged in from. If the + * connection is not a socket, let the ip address be 0.0.0.0. + */ + memset(&from, 0, sizeof(from)); + if (packet_connection_is_on_socket()) { + fromlen = sizeof(from); + if (getpeername(packet_get_connection_in(), + (struct sockaddr *) & from, &fromlen) < 0) { + debug("getpeername: %.100s", strerror(errno)); + fatal_cleanup(); + } + } + /* Record that there was a login on that terminal. */ + record_login(pid, s->tty, pw->pw_name, pw->pw_uid, hostname, + (struct sockaddr *)&from); + + /* Check if .hushlogin exists. */ + snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir); + quiet_login = stat(line, &st) >= 0; + + /* + * If the user has logged in before, display the time of last + * login. However, don't display anything extra if a command + * has been specified (so that ssh can be used to execute + * commands on a remote machine without users knowing they + * are going to another machine). Login(1) will do this for + * us as well, so check if login(1) is used + */ + if (command == NULL && last_login_time != 0 && !quiet_login && + !options.use_login) { + /* Convert the date to a string. */ + time_string = ctime(&last_login_time); + /* Remove the trailing newline. */ + if (strchr(time_string, '\n')) + *strchr(time_string, '\n') = 0; + /* Display the last login time. Host if displayed + if known. */ + if (strcmp(buf, "") == 0) + printf("Last login: %s\r\n", time_string); + else + printf("Last login: %s from %s\r\n", time_string, buf); + } + /* + * Print /etc/motd unless a command was specified or printing + * it was disabled in server options or login(1) will be + * used. Note that some machines appear to print it in + * /etc/profile or similar. + */ + if (command == NULL && options.print_motd && !quiet_login && + !options.use_login) { + /* Print /etc/motd if it exists. */ + f = fopen("/etc/motd", "r"); + if (f) { + while (fgets(line, sizeof(line), f)) + fputs(line, stdout); + fclose(f); + } + } + /* Do common processing for the child, such as execing the command. */ + do_child(command, pw, s->term, s->display, s->auth_proto, s->auth_data, s->tty); + /* NOTREACHED */ + } + if (pid < 0) + packet_disconnect("fork failed: %.100s", strerror(errno)); + s->pid = pid; + + /* Parent. Close the slave side of the pseudo tty. */ + close(ttyfd); + + /* + * Create another descriptor of the pty master side for use as the + * standard input. We could use the original descriptor, but this + * simplifies code in server_loop. The descriptor is bidirectional. + */ + fdout = dup(ptyfd); + if (fdout < 0) + packet_disconnect("dup #1 failed: %.100s", strerror(errno)); + + /* we keep a reference to the pty master */ + ptymaster = dup(ptyfd); + if (ptymaster < 0) + packet_disconnect("dup #2 failed: %.100s", strerror(errno)); + s->ptymaster = ptymaster; + + /* Enter interactive session. */ + server_loop(pid, ptyfd, fdout, -1); + /* server_loop _has_ closed ptyfd and fdout. */ + session_pty_cleanup(s); +} + +/* + * Sets the value of the given variable in the environment. If the variable + * already exists, its value is overriden. + */ +void +child_set_env(char ***envp, unsigned int *envsizep, const char *name, + const char *value) +{ + unsigned int i, namelen; + char **env; + + /* + * Find the slot where the value should be stored. If the variable + * already exists, we reuse the slot; otherwise we append a new slot + * at the end of the array, expanding if necessary. + */ + env = *envp; + namelen = strlen(name); + for (i = 0; env[i]; i++) + if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=') + break; + if (env[i]) { + /* Reuse the slot. */ + xfree(env[i]); + } else { + /* New variable. Expand if necessary. */ + if (i >= (*envsizep) - 1) { + (*envsizep) += 50; + env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *)); + } + /* Need to set the NULL pointer at end of array beyond the new slot. */ + env[i + 1] = NULL; + } + + /* Allocate space and format the variable in the appropriate slot. */ + env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1); + snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value); +} + +/* + * Reads environment variables from the given file and adds/overrides them + * into the environment. If the file does not exist, this does nothing. + * Otherwise, it must consist of empty lines, comments (line starts with '#') + * and assignments of the form name=value. No other forms are allowed. + */ +void +read_environment_file(char ***env, unsigned int *envsize, + const char *filename) +{ + FILE *f; + char buf[4096]; + char *cp, *value; + + f = fopen(filename, "r"); + if (!f) + return; + + while (fgets(buf, sizeof(buf), f)) { + for (cp = buf; *cp == ' ' || *cp == '\t'; cp++) + ; + if (!*cp || *cp == '#' || *cp == '\n') + continue; + if (strchr(cp, '\n')) + *strchr(cp, '\n') = '\0'; + value = strchr(cp, '='); + if (value == NULL) { + fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf); + continue; + } + /* Replace the equals sign by nul, and advance value to the value string. */ + *value = '\0'; + value++; + child_set_env(env, envsize, cp, value); + } + fclose(f); +} + +/* + * Performs common processing for the child, such as setting up the + * environment, closing extra file descriptors, setting the user and group + * ids, and executing the command or shell. + */ +void +do_child(const char *command, struct passwd * pw, const char *term, + const char *display, const char *auth_proto, + const char *auth_data, const char *ttyname) +{ + const char *shell, *cp = NULL; + char buf[256]; + FILE *f; + unsigned int envsize, i; + char **env; + extern char **environ; + struct stat st; + char *argv[10]; + + f = fopen("/etc/nologin", "r"); + if (f) { + /* /etc/nologin exists. Print its contents and exit. */ + while (fgets(buf, sizeof(buf), f)) + fputs(buf, stderr); + fclose(f); + if (pw->pw_uid != 0) + exit(254); + } + /* Set login name in the kernel. */ + if (setlogin(pw->pw_name) < 0) + error("setlogin failed: %s", strerror(errno)); + + /* Set uid, gid, and groups. */ + /* Login(1) does this as well, and it needs uid 0 for the "-h" + switch, so we let login(1) to this for us. */ + if (!options.use_login) { + if (getuid() == 0 || geteuid() == 0) { + if (setgid(pw->pw_gid) < 0) { + perror("setgid"); + exit(1); + } + /* Initialize the group list. */ + if (initgroups(pw->pw_name, pw->pw_gid) < 0) { + perror("initgroups"); + exit(1); + } + endgrent(); + + /* Permanently switch to the desired uid. */ + permanently_set_uid(pw->pw_uid); + } + if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) + fatal("Failed to set uids to %d.", (int) pw->pw_uid); + } + /* + * Get the shell from the password data. An empty shell field is + * legal, and means /bin/sh. + */ + shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; + +#ifdef AFS + /* Try to get AFS tokens for the local cell. */ + if (k_hasafs()) { + char cell[64]; + + if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) + krb_afslog(cell, 0); + + krb_afslog(0, 0); + } +#endif /* AFS */ + + /* Initialize the environment. */ + envsize = 100; + env = xmalloc(envsize * sizeof(char *)); + env[0] = NULL; + + if (!options.use_login) { + /* Set basic environment. */ + child_set_env(&env, &envsize, "USER", pw->pw_name); + child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); + child_set_env(&env, &envsize, "HOME", pw->pw_dir); + child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); + + snprintf(buf, sizeof buf, "%.200s/%.50s", + _PATH_MAILDIR, pw->pw_name); + child_set_env(&env, &envsize, "MAIL", buf); + + /* Normal systems set SHELL by default. */ + child_set_env(&env, &envsize, "SHELL", shell); + } + if (getenv("TZ")) + child_set_env(&env, &envsize, "TZ", getenv("TZ")); + + /* Set custom environment options from RSA authentication. */ + while (custom_environment) { + struct envstring *ce = custom_environment; + char *s = ce->s; + int i; + for (i = 0; s[i] != '=' && s[i]; i++); + if (s[i] == '=') { + s[i] = 0; + child_set_env(&env, &envsize, s, s + i + 1); + } + custom_environment = ce->next; + xfree(ce->s); + xfree(ce); + } + + snprintf(buf, sizeof buf, "%.50s %d %d", + get_remote_ipaddr(), get_remote_port(), get_local_port()); + child_set_env(&env, &envsize, "SSH_CLIENT", buf); + + if (ttyname) + child_set_env(&env, &envsize, "SSH_TTY", ttyname); + if (term) + child_set_env(&env, &envsize, "TERM", term); + if (display) + child_set_env(&env, &envsize, "DISPLAY", display); + +#ifdef KRB4 + { + extern char *ticket; + + if (ticket) + child_set_env(&env, &envsize, "KRBTKFILE", ticket); + } +#endif /* KRB4 */ + + if (xauthfile) + child_set_env(&env, &envsize, "XAUTHORITY", xauthfile); + if (auth_get_socket_name() != NULL) + child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, + auth_get_socket_name()); + + /* read $HOME/.ssh/environment. */ + if (!options.use_login) { + snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir); + read_environment_file(&env, &envsize, buf); + } + if (debug_flag) { + /* dump the environment */ + fprintf(stderr, "Environment:\n"); + for (i = 0; env[i]; i++) + fprintf(stderr, " %.200s\n", env[i]); + } + /* + * Close the connection descriptors; note that this is the child, and + * the server will still have the socket open, and it is important + * that we do not shutdown it. Note that the descriptors cannot be + * closed before building the environment, as we call + * get_remote_ipaddr there. + */ + if (packet_get_connection_in() == packet_get_connection_out()) + close(packet_get_connection_in()); + else { + close(packet_get_connection_in()); + close(packet_get_connection_out()); + } + /* + * Close all descriptors related to channels. They will still remain + * open in the parent. + */ + /* XXX better use close-on-exec? -markus */ + channel_close_all(); + + /* + * Close any extra file descriptors. Note that there may still be + * descriptors left by system functions. They will be closed later. + */ + endpwent(); + + /* + * Close any extra open file descriptors so that we don\'t have them + * hanging around in clients. Note that we want to do this after + * initgroups, because at least on Solaris 2.3 it leaves file + * descriptors open. + */ + for (i = 3; i < 64; i++) + close(i); + + /* Change current directory to the user\'s home directory. */ + if (chdir(pw->pw_dir) < 0) + fprintf(stderr, "Could not chdir to home directory %s: %s\n", + pw->pw_dir, strerror(errno)); + + /* + * Must take new environment into use so that .ssh/rc, /etc/sshrc and + * xauth are run in the proper environment. + */ + environ = env; + + /* + * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first + * in this order). + */ + if (!options.use_login) { + if (stat(SSH_USER_RC, &st) >= 0) { + if (debug_flag) + fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC); + + f = popen("/bin/sh " SSH_USER_RC, "w"); + if (f) { + if (auth_proto != NULL && auth_data != NULL) + fprintf(f, "%s %s\n", auth_proto, auth_data); + pclose(f); + } else + fprintf(stderr, "Could not run %s\n", SSH_USER_RC); + } else if (stat(SSH_SYSTEM_RC, &st) >= 0) { + if (debug_flag) + fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC); + + f = popen("/bin/sh " SSH_SYSTEM_RC, "w"); + if (f) { + if (auth_proto != NULL && auth_data != NULL) + fprintf(f, "%s %s\n", auth_proto, auth_data); + pclose(f); + } else + fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC); + } +#ifdef XAUTH_PATH + else { + /* Add authority data to .Xauthority if appropriate. */ + if (auth_proto != NULL && auth_data != NULL) { + if (debug_flag) + fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n", + XAUTH_PATH, display, auth_proto, auth_data); + + f = popen(XAUTH_PATH " -q -", "w"); + if (f) { + fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data); + pclose(f); + } else + fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH); + } + } +#endif /* XAUTH_PATH */ + + /* Get the last component of the shell name. */ + cp = strrchr(shell, '/'); + if (cp) + cp++; + else + cp = shell; + } + /* + * If we have no command, execute the shell. In this case, the shell + * name to be passed in argv[0] is preceded by '-' to indicate that + * this is a login shell. + */ + if (!command) { + if (!options.use_login) { + char buf[256]; + + /* + * Check for mail if we have a tty and it was enabled + * in server options. + */ + if (ttyname && options.check_mail) { + char *mailbox; + struct stat mailstat; + mailbox = getenv("MAIL"); + if (mailbox != NULL) { + if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0) + printf("No mail.\n"); + else if (mailstat.st_mtime < mailstat.st_atime) + printf("You have mail.\n"); + else + printf("You have new mail.\n"); + } + } + /* Start the shell. Set initial character to '-'. */ + buf[0] = '-'; + strncpy(buf + 1, cp, sizeof(buf) - 1); + buf[sizeof(buf) - 1] = 0; + + /* Execute the shell. */ + argv[0] = buf; + argv[1] = NULL; + execve(shell, argv, env); + + /* Executing the shell failed. */ + perror(shell); + exit(1); + + } else { + /* Launch login(1). */ + + execl("/usr/bin/login", "login", "-h", get_remote_ipaddr(), + "-p", "-f", "--", pw->pw_name, NULL); + + /* Login couldn't be executed, die. */ + + perror("login"); + exit(1); + } + } + /* + * Execute the command using the user's shell. This uses the -c + * option to execute the command. + */ + argv[0] = (char *) cp; + argv[1] = "-c"; + argv[2] = (char *) command; + argv[3] = NULL; + execve(shell, argv, env); + perror(shell); + exit(1); +} + +Session * +session_new(void) +{ + int i; + static int did_init = 0; + if (!did_init) { + debug("session_new: init"); + for(i = 0; i < MAX_SESSIONS; i++) { + sessions[i].used = 0; + sessions[i].self = i; + } + did_init = 1; + } + for(i = 0; i < MAX_SESSIONS; i++) { + Session *s = &sessions[i]; + if (! s->used) { + s->pid = 0; + s->chanid = -1; + s->ptyfd = -1; + s->ttyfd = -1; + s->term = NULL; + s->pw = NULL; + s->display = NULL; + s->screen = 0; + s->auth_data = NULL; + s->auth_proto = NULL; + s->used = 1; + debug("session_new: session %d", i); + return s; + } + } + return NULL; +} + +void +session_dump(void) +{ + int i; + for(i = 0; i < MAX_SESSIONS; i++) { + Session *s = &sessions[i]; + debug("dump: used %d session %d %p channel %d pid %d", + s->used, + s->self, + s, + s->chanid, + s->pid); + } +} + +void +session_pty_cleanup(Session *s) +{ + if (s == NULL || s->ttyfd == -1) + return; + + debug("session_pty_cleanup: session %i release %s", s->self, s->tty); + + /* Cancel the cleanup function. */ + fatal_remove_cleanup(pty_cleanup_proc, (void *)s); + + /* Record that the user has logged out. */ + record_logout(s->pid, s->tty); + + /* Release the pseudo-tty. */ + pty_release(s->tty); + + /* + * Close the server side of the socket pairs. We must do this after + * the pty cleanup, so that another process doesn't get this pty + * while we're still cleaning up. + */ + if (close(s->ptymaster) < 0) + error("close(s->ptymaster): %s", strerror(errno)); +} diff --git a/usr.bin/ssh/session.h b/usr.bin/ssh/session.h new file mode 100644 index 00000000000..2051b737d16 --- /dev/null +++ b/usr.bin/ssh/session.h @@ -0,0 +1,7 @@ +#ifndef SESSION_H +#define SESSION_H + +/* SSH1 */ +void do_authenticated(struct passwd * pw); + +#endif diff --git a/usr.bin/ssh/sshd.c b/usr.bin/ssh/sshd.c index 282444a12c9..a5dc749885c 100644 --- a/usr.bin/ssh/sshd.c +++ b/usr.bin/ssh/sshd.c @@ -11,21 +11,28 @@ */ #include "includes.h" -RCSID("$OpenBSD: sshd.c,v 1.95 2000/03/28 20:31:29 markus Exp $"); +RCSID("$OpenBSD: sshd.c,v 1.96 2000/03/28 21:15:45 markus Exp $"); #include "xmalloc.h" #include "rsa.h" #include "ssh.h" #include "pty.h" #include "packet.h" -#include "buffer.h" #include "cipher.h" #include "mpaux.h" #include "servconf.h" #include "uidswap.h" -#include "match.h" -#include "channels.h" #include "compat.h" +#include "buffer.h" + +#include +#include +#include +#include +#include +#include "key.h" + +#include "auth.h" #ifdef LIBWRAP #include @@ -38,9 +45,6 @@ int deny_severity = LOG_WARNING; #define O_NOCTTY 0 #endif -/* Local Xauthority file. */ -static char *xauthfile = NULL; - /* Server configuration options. */ ServerOptions options; @@ -86,21 +90,7 @@ int num_listen_socks = 0; * sshd will skip the version-number exchange */ char *client_version_string = NULL; - -/* Flags set in auth-rsa from authorized_keys flags. These are set in auth-rsa.c. */ -int no_port_forwarding_flag = 0; -int no_agent_forwarding_flag = 0; -int no_x11_forwarding_flag = 0; -int no_pty_flag = 0; - -/* RSA authentication "command=" option. */ -char *forced_command = NULL; - -/* RSA authentication "environment=" options. */ -struct envstring *custom_environment = NULL; - -/* Session id for the current session. */ -unsigned char session_id[16]; +char *server_version_string = NULL; /* * Any really sensitive data in the application is contained in this @@ -128,43 +118,11 @@ int received_sighup = 0; the private key. */ RSA *public_key; -/* Prototypes for various functions defined later in this file. */ -void do_ssh_kex(); -void do_authentication(); -void do_authloop(struct passwd * pw); -void do_fake_authloop(char *user); -void do_authenticated(struct passwd * pw); -void do_exec_pty(const char *command, int ptyfd, int ttyfd, - const char *ttyname, struct passwd * pw, const char *term, - const char *display, const char *auth_proto, - const char *auth_data); -void do_exec_no_pty(const char *command, struct passwd * pw, - const char *display, const char *auth_proto, - const char *auth_data); -void do_child(const char *command, struct passwd * pw, const char *term, - const char *display, const char *auth_proto, - const char *auth_data, const char *ttyname); +/* session identifier, used by RSA-auth */ +unsigned char session_id[16]; -/* - * Remove local Xauthority file. - */ -void -xauthfile_cleanup_proc(void *ignore) -{ - debug("xauthfile_cleanup_proc called"); - - if (xauthfile != NULL) { - char *p; - unlink(xauthfile); - p = strrchr(xauthfile, '/'); - if (p != NULL) { - *p = '\0'; - rmdir(xauthfile); - } - xfree(xauthfile); - xauthfile = NULL; - } -} +/* Prototypes for various functions defined later in this file. */ +void do_ssh1_kex(); /* * Close all listening sockets @@ -247,35 +205,6 @@ grace_alarm_handler(int sig) fatal("Timeout before authentication for %s.", get_remote_ipaddr()); } -/* - * convert ssh auth msg type into description - */ -char * -get_authname(int type) -{ - static char buf[1024]; - switch (type) { - case SSH_CMSG_AUTH_PASSWORD: - return "password"; - case SSH_CMSG_AUTH_RSA: - return "rsa"; - case SSH_CMSG_AUTH_RHOSTS_RSA: - return "rhosts-rsa"; - case SSH_CMSG_AUTH_RHOSTS: - return "rhosts"; -#ifdef KRB4 - case SSH_CMSG_AUTH_KERBEROS: - return "kerberos"; -#endif -#ifdef SKEY - case SSH_CMSG_AUTH_TIS_RESPONSE: - return "s/key"; -#endif - } - snprintf(buf, sizeof buf, "bad-auth-msg-%d", type); - return buf; -} - /* * Signal handler for the key regeneration alarm. Note that this * alarm only occurs in the daemon waiting for connections, and it does not @@ -313,6 +242,88 @@ key_regeneration_alarm(int sig) errno = save_errno; } +void +sshd_exchange_identification(int sock_in, int sock_out) +{ + int i; + int remote_major, remote_minor; + char *s; + char buf[256]; /* Must not be larger than remote_version. */ + char remote_version[256]; /* Must be at least as big as buf. */ + + snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", + PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION); + server_version_string = xstrdup(buf); + + if (client_version_string == NULL) { + /* Send our protocol version identification. */ + if (atomicio(write, sock_out, server_version_string, strlen(server_version_string)) + != strlen(server_version_string)) { + log("Could not write ident string to %s.", get_remote_ipaddr()); + fatal_cleanup(); + } + + /* Read other side\'s version identification. */ + for (i = 0; i < sizeof(buf) - 1; i++) { + if (read(sock_in, &buf[i], 1) != 1) { + log("Did not receive ident string from %s.", get_remote_ipaddr()); + fatal_cleanup(); + } + if (buf[i] == '\r') { + buf[i] = '\n'; + buf[i + 1] = 0; + continue; + /*break; XXX eat \r */ + } + if (buf[i] == '\n') { + /* buf[i] == '\n' */ + buf[i + 1] = 0; + break; + } + } + buf[sizeof(buf) - 1] = 0; + client_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(client_version_string, "SSH-%d.%d-%[^\n]\n", + &remote_major, &remote_minor, remote_version) != 3) { + s = "Protocol mismatch.\n"; + (void) atomicio(write, sock_out, s, strlen(s)); + close(sock_in); + close(sock_out); + log("Bad protocol version identification '%.100s' from %s", + client_version_string, get_remote_ipaddr()); + fatal_cleanup(); + } + debug("Client protocol version %d.%d; client software version %.100s", + remote_major, remote_minor, remote_version); + + switch(remote_major) { + case 1: + if (remote_minor < 3) { + packet_disconnect("Your ssh version is too old and" + "is no longer supported. Please install a newer version."); + } else if (remote_minor == 3) { + /* note that this disables agent-forwarding */ + enable_compat13(); + } + break; + default: + s = "Protocol major versions differ.\n"; + (void) atomicio(write, sock_out, s, strlen(s)); + close(sock_in); + close(sock_out); + log("Protocol major versions differ for %s: %d vs. %d", + get_remote_ipaddr(), PROTOCOL_MAJOR, remote_major); + fatal_cleanup(); + break; + } +} + /* * Main program for the daemon. */ @@ -323,12 +334,9 @@ main(int ac, char **av) extern int optind; int opt, sock_in = 0, sock_out = 0, newsock, i, fdsetsz, pid, on = 1; socklen_t fromlen; - int remote_major, remote_minor; int silentrsa = 0; fd_set *fdset; struct sockaddr_storage from; - char buf[100]; /* Must not be larger than remote_version. */ - char remote_version[100]; /* Must be at least as big as buf. */ const char *remote_ip; int remote_port; char *comment; @@ -791,73 +799,7 @@ main(int ac, char **av) if (!debug_flag) alarm(options.login_grace_time); - if (client_version_string != NULL) { - /* we are exec'ed by sshd2, so skip exchange of protocol version */ - strlcpy(buf, client_version_string, sizeof(buf)); - } else { - /* Send our protocol version identification. */ - snprintf(buf, sizeof buf, "SSH-%d.%d-%.100s\n", - PROTOCOL_MAJOR, PROTOCOL_MINOR, SSH_VERSION); - if (atomicio(write, sock_out, buf, strlen(buf)) != strlen(buf)) { - log("Could not write ident string to %s.", remote_ip); - fatal_cleanup(); - } - - /* Read other side\'s version identification. */ - for (i = 0; i < sizeof(buf) - 1; i++) { - if (read(sock_in, &buf[i], 1) != 1) { - log("Did not receive ident string from %s.", remote_ip); - fatal_cleanup(); - } - if (buf[i] == '\r') { - buf[i] = '\n'; - buf[i + 1] = 0; - break; - } - if (buf[i] == '\n') { - /* buf[i] == '\n' */ - buf[i + 1] = 0; - break; - } - } - buf[sizeof(buf) - 1] = 0; - } - - /* - * Check that the versions match. In future this might accept - * several versions and set appropriate flags to handle them. - */ - if (sscanf(buf, "SSH-%d.%d-%[^\n]\n", &remote_major, &remote_minor, - remote_version) != 3) { - char *s = "Protocol mismatch.\n"; - - (void) atomicio(write, sock_out, s, strlen(s)); - close(sock_in); - close(sock_out); - log("Bad protocol version identification '%.100s' from %s", - buf, remote_ip); - fatal_cleanup(); - } - debug("Client protocol version %d.%d; client software version %.100s", - remote_major, remote_minor, remote_version); - if (remote_major != PROTOCOL_MAJOR) { - char *s = "Protocol major versions differ.\n"; - - (void) atomicio(write, sock_out, s, strlen(s)); - close(sock_in); - close(sock_out); - log("Protocol major versions differ for %s: %d vs. %d", - remote_ip, PROTOCOL_MAJOR, remote_major); - fatal_cleanup(); - } - /* Check that the client has sufficiently high software version. */ - if (remote_major == 1 && remote_minor < 3) - packet_disconnect("Your ssh version is too old and is no longer supported. Please install a newer version."); - - if (remote_major == 1 && remote_minor == 3) { - /* note that this disables agent-forwarding */ - enable_compat13(); - } + sshd_exchange_identification(sock_in, sock_out); /* * Check that the connection comes from a privileged port. Rhosts- * and Rhosts-RSA-Authentication only make sense from priviledged @@ -881,8 +823,7 @@ main(int ac, char **av) packet_set_nonblocking(); /* perform the key exchange */ - do_ssh_kex(); - + do_ssh1_kex(); /* authenticate user and start session */ do_authentication(); @@ -892,10 +833,6 @@ main(int ac, char **av) (void) dest_tkt(); #endif /* KRB4 */ - /* Cleanup user's local Xauthority file. */ - if (xauthfile) - xauthfile_cleanup_proc(NULL); - /* The connection has been terminated. */ verbose("Closing connection to %.100s", remote_ip); packet_close(); @@ -906,7 +843,7 @@ main(int ac, char **av) * SSH1 key exchange */ void -do_ssh_kex() +do_ssh1_kex() { int i, len; int plen, slen; @@ -1093,1463 +1030,3 @@ do_ssh_kex() packet_send(); packet_write_wait(); } - - -/* - * Check if the user is allowed to log in via ssh. If user is listed in - * DenyUsers or user's primary group is listed in DenyGroups, false will - * be returned. If AllowUsers isn't empty and user isn't listed there, or - * if AllowGroups isn't empty and user isn't listed there, false will be - * returned. - * If the user's shell is not executable, false will be returned. - * Otherwise true is returned. - */ -static int -allowed_user(struct passwd * pw) -{ - struct stat st; - struct group *grp; - int i; - - /* Shouldn't be called if pw is NULL, but better safe than sorry... */ - if (!pw) - return 0; - - /* deny if shell does not exists or is not executable */ - if (stat(pw->pw_shell, &st) != 0) - return 0; - if (!((st.st_mode & S_IFREG) && (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)))) - return 0; - - /* Return false if user is listed in DenyUsers */ - if (options.num_deny_users > 0) { - if (!pw->pw_name) - return 0; - for (i = 0; i < options.num_deny_users; i++) - if (match_pattern(pw->pw_name, options.deny_users[i])) - return 0; - } - /* Return false if AllowUsers isn't empty and user isn't listed there */ - if (options.num_allow_users > 0) { - if (!pw->pw_name) - return 0; - for (i = 0; i < options.num_allow_users; i++) - if (match_pattern(pw->pw_name, options.allow_users[i])) - break; - /* i < options.num_allow_users iff we break for loop */ - if (i >= options.num_allow_users) - return 0; - } - /* Get the primary group name if we need it. Return false if it fails */ - if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { - grp = getgrgid(pw->pw_gid); - if (!grp) - return 0; - - /* Return false if user's group is listed in DenyGroups */ - if (options.num_deny_groups > 0) { - if (!grp->gr_name) - return 0; - for (i = 0; i < options.num_deny_groups; i++) - if (match_pattern(grp->gr_name, options.deny_groups[i])) - return 0; - } - /* - * Return false if AllowGroups isn't empty and user's group - * isn't listed there - */ - if (options.num_allow_groups > 0) { - if (!grp->gr_name) - return 0; - for (i = 0; i < options.num_allow_groups; i++) - if (match_pattern(grp->gr_name, options.allow_groups[i])) - break; - /* i < options.num_allow_groups iff we break for - loop */ - if (i >= options.num_allow_groups) - return 0; - } - } - /* We found no reason not to let this user try to log on... */ - return 1; -} - -/* - * Performs authentication of an incoming connection. Session key has already - * been exchanged and encryption is enabled. - */ -void -do_authentication() -{ - struct passwd *pw, pwcopy; - int plen; - unsigned int ulen; - char *user; - - /* Get the name of the user that we wish to log in as. */ - packet_read_expect(&plen, SSH_CMSG_USER); - - /* Get the user name. */ - user = packet_get_string(&ulen); - packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER); - - setproctitle("%s", user); - -#ifdef AFS - /* If machine has AFS, set process authentication group. */ - if (k_hasafs()) { - k_setpag(); - k_unlog(); - } -#endif /* AFS */ - - /* Verify that the user is a valid user. */ - pw = getpwnam(user); - if (!pw || !allowed_user(pw)) - do_fake_authloop(user); - xfree(user); - - /* Take a copy of the returned structure. */ - memset(&pwcopy, 0, sizeof(pwcopy)); - pwcopy.pw_name = xstrdup(pw->pw_name); - pwcopy.pw_passwd = xstrdup(pw->pw_passwd); - pwcopy.pw_uid = pw->pw_uid; - pwcopy.pw_gid = pw->pw_gid; - pwcopy.pw_dir = xstrdup(pw->pw_dir); - pwcopy.pw_shell = xstrdup(pw->pw_shell); - pw = &pwcopy; - - /* - * If we are not running as root, the user must have the same uid as - * the server. - */ - if (getuid() != 0 && pw->pw_uid != getuid()) - packet_disconnect("Cannot change user when server not running as root."); - - debug("Attempting authentication for %.100s.", pw->pw_name); - - /* If the user has no password, accept authentication immediately. */ - if (options.password_authentication && -#ifdef KRB4 - (!options.kerberos_authentication || options.kerberos_or_local_passwd) && -#endif /* KRB4 */ - auth_password(pw, "")) { - /* Authentication with empty password succeeded. */ - log("Login for user %s from %.100s, accepted without authentication.", - pw->pw_name, get_remote_ipaddr()); - } else { - /* Loop until the user has been authenticated or the - connection is closed, do_authloop() returns only if - authentication is successfull */ - do_authloop(pw); - } - - /* The user has been authenticated and accepted. */ - packet_start(SSH_SMSG_SUCCESS); - packet_send(); - packet_write_wait(); - - /* Perform session preparation. */ - do_authenticated(pw); -} - -#define AUTH_FAIL_MAX 6 -#define AUTH_FAIL_LOG (AUTH_FAIL_MAX/2) -#define AUTH_FAIL_MSG "Too many authentication failures for %.100s" - -/* - * read packets and try to authenticate local user *pw. - * return if authentication is successfull - */ -void -do_authloop(struct passwd * pw) -{ - int attempt = 0; - unsigned int bits; - RSA *client_host_key; - BIGNUM *n; - char *client_user, *password; - char user[1024]; - unsigned int dlen; - int plen, nlen, elen; - unsigned int ulen; - int type = 0; - void (*authlog) (const char *fmt,...) = verbose; - - /* Indicate that authentication is needed. */ - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); - - for (attempt = 1;; attempt++) { - int authenticated = 0; - strlcpy(user, "", sizeof user); - - /* Get a packet from the client. */ - type = packet_read(&plen); - - /* Process the packet. */ - switch (type) { -#ifdef AFS - case SSH_CMSG_HAVE_KERBEROS_TGT: - if (!options.kerberos_tgt_passing) { - /* packet_get_all(); */ - verbose("Kerberos tgt passing disabled."); - break; - } else { - /* Accept Kerberos tgt. */ - char *tgt = packet_get_string(&dlen); - packet_integrity_check(plen, 4 + dlen, type); - if (!auth_kerberos_tgt(pw, tgt)) - verbose("Kerberos tgt REFUSED for %s", pw->pw_name); - xfree(tgt); - } - continue; - - case SSH_CMSG_HAVE_AFS_TOKEN: - if (!options.afs_token_passing || !k_hasafs()) { - /* packet_get_all(); */ - verbose("AFS token passing disabled."); - break; - } else { - /* Accept AFS token. */ - char *token_string = packet_get_string(&dlen); - packet_integrity_check(plen, 4 + dlen, type); - if (!auth_afs_token(pw, token_string)) - verbose("AFS token REFUSED for %s", pw->pw_name); - xfree(token_string); - } - continue; -#endif /* AFS */ -#ifdef KRB4 - case SSH_CMSG_AUTH_KERBEROS: - if (!options.kerberos_authentication) { - /* packet_get_all(); */ - verbose("Kerberos authentication disabled."); - break; - } else { - /* Try Kerberos v4 authentication. */ - KTEXT_ST auth; - char *tkt_user = NULL; - char *kdata = packet_get_string((unsigned int *) &auth.length); - packet_integrity_check(plen, 4 + auth.length, type); - - if (auth.length < MAX_KTXT_LEN) - memcpy(auth.dat, kdata, auth.length); - xfree(kdata); - - authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user); - - if (authenticated) { - snprintf(user, sizeof user, " tktuser %s", tkt_user); - xfree(tkt_user); - } - } - break; -#endif /* KRB4 */ - - case SSH_CMSG_AUTH_RHOSTS: - if (!options.rhosts_authentication) { - verbose("Rhosts authentication disabled."); - break; - } - /* - * Get client user name. Note that we just have to - * trust the client; this is one reason why rhosts - * authentication is insecure. (Another is - * IP-spoofing on a local network.) - */ - client_user = packet_get_string(&ulen); - packet_integrity_check(plen, 4 + ulen, type); - - /* Try to authenticate using /etc/hosts.equiv and - .rhosts. */ - authenticated = auth_rhosts(pw, client_user); - - snprintf(user, sizeof user, " ruser %s", client_user); - xfree(client_user); - break; - - case SSH_CMSG_AUTH_RHOSTS_RSA: - if (!options.rhosts_rsa_authentication) { - verbose("Rhosts with RSA authentication disabled."); - break; - } - /* - * Get client user name. Note that we just have to - * trust the client; root on the client machine can - * claim to be any user. - */ - client_user = packet_get_string(&ulen); - - /* Get the client host key. */ - client_host_key = RSA_new(); - if (client_host_key == NULL) - fatal("RSA_new failed"); - client_host_key->e = BN_new(); - client_host_key->n = BN_new(); - if (client_host_key->e == NULL || client_host_key->n == NULL) - fatal("BN_new failed"); - bits = packet_get_int(); - packet_get_bignum(client_host_key->e, &elen); - packet_get_bignum(client_host_key->n, &nlen); - - if (bits != BN_num_bits(client_host_key->n)) - error("Warning: keysize mismatch for client_host_key: " - "actual %d, announced %d", BN_num_bits(client_host_key->n), bits); - packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type); - - authenticated = auth_rhosts_rsa(pw, client_user, client_host_key); - RSA_free(client_host_key); - - snprintf(user, sizeof user, " ruser %s", client_user); - xfree(client_user); - break; - - case SSH_CMSG_AUTH_RSA: - if (!options.rsa_authentication) { - verbose("RSA authentication disabled."); - break; - } - /* RSA authentication requested. */ - n = BN_new(); - packet_get_bignum(n, &nlen); - packet_integrity_check(plen, nlen, type); - authenticated = auth_rsa(pw, n); - BN_clear_free(n); - break; - - case SSH_CMSG_AUTH_PASSWORD: - if (!options.password_authentication) { - verbose("Password authentication disabled."); - break; - } - /* - * Read user password. It is in plain text, but was - * transmitted over the encrypted channel so it is - * not visible to an outside observer. - */ - password = packet_get_string(&dlen); - packet_integrity_check(plen, 4 + dlen, type); - - /* Try authentication with the password. */ - authenticated = auth_password(pw, password); - - memset(password, 0, strlen(password)); - xfree(password); - break; - -#ifdef SKEY - case SSH_CMSG_AUTH_TIS: - debug("rcvd SSH_CMSG_AUTH_TIS"); - if (options.skey_authentication == 1) { - char *skeyinfo = skey_keyinfo(pw->pw_name); - if (skeyinfo == NULL) { - debug("generating fake skeyinfo for %.100s.", pw->pw_name); - skeyinfo = skey_fake_keyinfo(pw->pw_name); - } - if (skeyinfo != NULL) { - /* we send our s/key- in tis-challenge messages */ - debug("sending challenge '%s'", skeyinfo); - packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); - packet_put_string(skeyinfo, strlen(skeyinfo)); - packet_send(); - packet_write_wait(); - continue; - } - } - break; - case SSH_CMSG_AUTH_TIS_RESPONSE: - debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE"); - if (options.skey_authentication == 1) { - char *response = packet_get_string(&dlen); - debug("skey response == '%s'", response); - packet_integrity_check(plen, 4 + dlen, type); - authenticated = (skey_haskey(pw->pw_name) == 0 && - skey_passcheck(pw->pw_name, response) != -1); - xfree(response); - } - break; -#else - case SSH_CMSG_AUTH_TIS: - /* TIS Authentication is unsupported */ - log("TIS authentication unsupported."); - break; -#endif - - default: - /* - * Any unknown messages will be ignored (and failure - * returned) during authentication. - */ - log("Unknown message during authentication: type %d", type); - break; - } - - /* - * Check if the user is logging in as root and root logins - * are disallowed. - * Note that root login is allowed for forced commands. - */ - if (authenticated && pw->pw_uid == 0 && !options.permit_root_login) { - if (forced_command) { - log("Root login accepted for forced command."); - } else { - authenticated = 0; - log("ROOT LOGIN REFUSED FROM %.200s", - get_canonical_hostname()); - } - } - - /* Raise logging level */ - if (authenticated || - attempt == AUTH_FAIL_LOG || - type == SSH_CMSG_AUTH_PASSWORD) - authlog = log; - - authlog("%s %s for %.200s from %.200s port %d%s", - authenticated ? "Accepted" : "Failed", - get_authname(type), - pw->pw_uid == 0 ? "ROOT" : pw->pw_name, - get_remote_ipaddr(), - get_remote_port(), - user); - - if (authenticated) - return; - - if (attempt > AUTH_FAIL_MAX) - packet_disconnect(AUTH_FAIL_MSG, pw->pw_name); - - /* Send a message indicating that the authentication attempt failed. */ - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); - } -} - -/* - * The user does not exist or access is denied, - * but fake indication that authentication is needed. - */ -void -do_fake_authloop(char *user) -{ - int attempt = 0; - - log("Faking authloop for illegal user %.200s from %.200s port %d", - user, - get_remote_ipaddr(), - get_remote_port()); - - /* Indicate that authentication is needed. */ - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); - - /* - * Keep reading packets, and always respond with a failure. This is - * to avoid disclosing whether such a user really exists. - */ - for (attempt = 1;; attempt++) { - /* Read a packet. This will not return if the client disconnects. */ - int plen; - int type = packet_read(&plen); -#ifdef SKEY - unsigned int dlen; - char *password, *skeyinfo; - /* Try to send a fake s/key challenge. */ - if (options.skey_authentication == 1 && - (skeyinfo = skey_fake_keyinfo(user)) != NULL) { - password = NULL; - if (type == SSH_CMSG_AUTH_TIS) { - packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); - packet_put_string(skeyinfo, strlen(skeyinfo)); - packet_send(); - packet_write_wait(); - continue; - } else if (type == SSH_CMSG_AUTH_PASSWORD && - options.password_authentication && - (password = packet_get_string(&dlen)) != NULL && - dlen == 5 && - strncasecmp(password, "s/key", 5) == 0 ) { - packet_send_debug(skeyinfo); - } - if (password != NULL) - xfree(password); - } -#endif - if (attempt > AUTH_FAIL_MAX) - packet_disconnect(AUTH_FAIL_MSG, user); - - /* - * Send failure. This should be indistinguishable from a - * failed authentication. - */ - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); - } - /* NOTREACHED */ - abort(); -} - -struct pty_cleanup_context { - const char *ttyname; - int pid; -}; - -/* - * Function to perform cleanup if we get aborted abnormally (e.g., due to a - * dropped connection). - */ -void -pty_cleanup_proc(void *context) -{ - struct pty_cleanup_context *cu = context; - - debug("pty_cleanup_proc called"); - - /* Record that the user has logged out. */ - record_logout(cu->pid, cu->ttyname); - - /* Release the pseudo-tty. */ - pty_release(cu->ttyname); -} - -/* simple cleanup: chown tty slave back to root */ -static void -pty_release_proc(void *tty) -{ - char *ttyname = tty; - pty_release(ttyname); -} - -/* - * Prepares for an interactive session. This is called after the user has - * been successfully authenticated. During this message exchange, pseudo - * terminals are allocated, X11, TCP/IP, and authentication agent forwardings - * are requested, etc. - */ -void -do_authenticated(struct passwd * pw) -{ - int type; - int compression_level = 0, enable_compression_after_reply = 0; - int have_pty = 0, ptyfd = -1, ttyfd = -1; - int row, col, xpixel, ypixel, screen; - char ttyname[64]; - char *command, *term = NULL, *display = NULL, *proto = NULL, *data = NULL; - int plen; - unsigned int dlen; - int n_bytes; - - /* - * Cancel the alarm we set to limit the time taken for - * authentication. - */ - alarm(0); - - /* - * Inform the channel mechanism that we are the server side and that - * the client may request to connect to any port at all. (The user - * could do it anyway, and we wouldn\'t know what is permitted except - * by the client telling us, so we can equally well trust the client - * not to request anything bogus.) - */ - if (!no_port_forwarding_flag) - channel_permit_all_opens(); - - /* - * We stay in this loop until the client requests to execute a shell - * or a command. - */ - while (1) { - - /* Get a packet from the client. */ - type = packet_read(&plen); - - /* Process the packet. */ - switch (type) { - case SSH_CMSG_REQUEST_COMPRESSION: - packet_integrity_check(plen, 4, type); - compression_level = packet_get_int(); - if (compression_level < 1 || compression_level > 9) { - packet_send_debug("Received illegal compression level %d.", - compression_level); - goto fail; - } - /* Enable compression after we have responded with SUCCESS. */ - enable_compression_after_reply = 1; - break; - - case SSH_CMSG_REQUEST_PTY: - if (no_pty_flag) { - debug("Allocating a pty not permitted for this authentication."); - goto fail; - } - if (have_pty) - packet_disconnect("Protocol error: you already have a pty."); - - debug("Allocating pty."); - - /* Allocate a pty and open it. */ - if (!pty_allocate(&ptyfd, &ttyfd, ttyname, - sizeof(ttyname))) { - error("Failed to allocate pty."); - goto fail; - } - fatal_add_cleanup(pty_release_proc, (void *)ttyname); - pty_setowner(pw, ttyname); - - /* Get TERM from the packet. Note that the value may be of arbitrary length. */ - term = packet_get_string(&dlen); - packet_integrity_check(dlen, strlen(term), type); - - /* Remaining bytes */ - n_bytes = plen - (4 + dlen + 4 * 4); - - if (strcmp(term, "") == 0) { - xfree(term); - term = NULL; - } - - /* Get window size from the packet. */ - row = packet_get_int(); - col = packet_get_int(); - xpixel = packet_get_int(); - ypixel = packet_get_int(); - pty_change_window_size(ptyfd, row, col, xpixel, ypixel); - - /* Get tty modes from the packet. */ - tty_parse_modes(ttyfd, &n_bytes); - packet_integrity_check(plen, 4 + dlen + 4 * 4 + n_bytes, type); - - /* Indicate that we now have a pty. */ - have_pty = 1; - break; - - case SSH_CMSG_X11_REQUEST_FORWARDING: - if (!options.x11_forwarding) { - packet_send_debug("X11 forwarding disabled in server configuration file."); - goto fail; - } -#ifdef XAUTH_PATH - if (no_x11_forwarding_flag) { - packet_send_debug("X11 forwarding not permitted for this authentication."); - goto fail; - } - debug("Received request for X11 forwarding with auth spoofing."); - if (display) - packet_disconnect("Protocol error: X11 display already set."); - { - unsigned int proto_len, data_len; - proto = packet_get_string(&proto_len); - data = packet_get_string(&data_len); - packet_integrity_check(plen, 4 + proto_len + 4 + data_len + 4, type); - } - if (packet_get_protocol_flags() & SSH_PROTOFLAG_SCREEN_NUMBER) - screen = packet_get_int(); - else - screen = 0; - display = x11_create_display_inet(screen, options.x11_display_offset); - if (!display) - goto fail; - - /* Setup to always have a local .Xauthority. */ - xauthfile = xmalloc(MAXPATHLEN); - strlcpy(xauthfile, "/tmp/ssh-XXXXXXXX", MAXPATHLEN); - temporarily_use_uid(pw->pw_uid); - if (mkdtemp(xauthfile) == NULL) { - restore_uid(); - error("private X11 dir: mkdtemp %s failed: %s", - xauthfile, strerror(errno)); - xfree(xauthfile); - xauthfile = NULL; - goto fail; - } - strlcat(xauthfile, "/cookies", MAXPATHLEN); - open(xauthfile, O_RDWR|O_CREAT|O_EXCL, 0600); - restore_uid(); - fatal_add_cleanup(xauthfile_cleanup_proc, NULL); - break; -#else /* XAUTH_PATH */ - packet_send_debug("No xauth program; cannot forward with spoofing."); - goto fail; -#endif /* XAUTH_PATH */ - - case SSH_CMSG_AGENT_REQUEST_FORWARDING: - if (no_agent_forwarding_flag || compat13) { - debug("Authentication agent forwarding not permitted for this authentication."); - goto fail; - } - debug("Received authentication agent forwarding request."); - auth_input_request_forwarding(pw); - break; - - case SSH_CMSG_PORT_FORWARD_REQUEST: - if (no_port_forwarding_flag) { - debug("Port forwarding not permitted for this authentication."); - goto fail; - } - debug("Received TCP/IP port forwarding request."); - channel_input_port_forward_request(pw->pw_uid == 0); - break; - - case SSH_CMSG_MAX_PACKET_SIZE: - if (packet_set_maxsize(packet_get_int()) < 0) - goto fail; - break; - - case SSH_CMSG_EXEC_SHELL: - /* Set interactive/non-interactive mode. */ - packet_set_interactive(have_pty || display != NULL, - options.keepalives); - - if (forced_command != NULL) - goto do_forced_command; - debug("Forking shell."); - packet_integrity_check(plen, 0, type); - if (have_pty) - do_exec_pty(NULL, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); - else - do_exec_no_pty(NULL, pw, display, proto, data); - return; - - case SSH_CMSG_EXEC_CMD: - /* Set interactive/non-interactive mode. */ - packet_set_interactive(have_pty || display != NULL, - options.keepalives); - - if (forced_command != NULL) - goto do_forced_command; - /* Get command from the packet. */ - { - unsigned int dlen; - command = packet_get_string(&dlen); - debug("Executing command '%.500s'", command); - packet_integrity_check(plen, 4 + dlen, type); - } - if (have_pty) - do_exec_pty(command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); - else - do_exec_no_pty(command, pw, display, proto, data); - xfree(command); - return; - - default: - /* - * Any unknown messages in this phase are ignored, - * and a failure message is returned. - */ - log("Unknown packet type received after authentication: %d", type); - goto fail; - } - - /* The request was successfully processed. */ - packet_start(SSH_SMSG_SUCCESS); - packet_send(); - packet_write_wait(); - - /* Enable compression now that we have replied if appropriate. */ - if (enable_compression_after_reply) { - enable_compression_after_reply = 0; - packet_start_compression(compression_level); - } - continue; - -fail: - /* The request failed. */ - packet_start(SSH_SMSG_FAILURE); - packet_send(); - packet_write_wait(); - continue; - -do_forced_command: - /* - * There is a forced command specified for this login. - * Execute it. - */ - debug("Executing forced command: %.900s", forced_command); - if (have_pty) - do_exec_pty(forced_command, ptyfd, ttyfd, ttyname, pw, term, display, proto, data); - else - do_exec_no_pty(forced_command, pw, display, proto, data); - return; - } -} - -/* - * This is called to fork and execute a command when we have no tty. This - * will call do_child from the child, and server_loop from the parent after - * setting up file descriptors and such. - */ -void -do_exec_no_pty(const char *command, struct passwd * pw, - const char *display, const char *auth_proto, - const char *auth_data) -{ - int pid; - -#ifdef USE_PIPES - int pin[2], pout[2], perr[2]; - /* Allocate pipes for communicating with the program. */ - if (pipe(pin) < 0 || pipe(pout) < 0 || pipe(perr) < 0) - packet_disconnect("Could not create pipes: %.100s", - strerror(errno)); -#else /* USE_PIPES */ - int inout[2], err[2]; - /* Uses socket pairs to communicate with the program. */ - if (socketpair(AF_UNIX, SOCK_STREAM, 0, inout) < 0 || - socketpair(AF_UNIX, SOCK_STREAM, 0, err) < 0) - packet_disconnect("Could not create socket pairs: %.100s", - strerror(errno)); -#endif /* USE_PIPES */ - - setproctitle("%s@notty", pw->pw_name); - - /* Fork the child. */ - if ((pid = fork()) == 0) { - /* Child. Reinitialize the log since the pid has changed. */ - log_init(av0, options.log_level, options.log_facility, log_stderr); - - /* - * Create a new session and process group since the 4.4BSD - * setlogin() affects the entire process group. - */ - if (setsid() < 0) - error("setsid failed: %.100s", strerror(errno)); - -#ifdef USE_PIPES - /* - * Redirect stdin. We close the parent side of the socket - * pair, and make the child side the standard input. - */ - close(pin[1]); - if (dup2(pin[0], 0) < 0) - perror("dup2 stdin"); - close(pin[0]); - - /* Redirect stdout. */ - close(pout[0]); - if (dup2(pout[1], 1) < 0) - perror("dup2 stdout"); - close(pout[1]); - - /* Redirect stderr. */ - close(perr[0]); - if (dup2(perr[1], 2) < 0) - perror("dup2 stderr"); - close(perr[1]); -#else /* USE_PIPES */ - /* - * Redirect stdin, stdout, and stderr. Stdin and stdout will - * use the same socket, as some programs (particularly rdist) - * seem to depend on it. - */ - close(inout[1]); - close(err[1]); - if (dup2(inout[0], 0) < 0) /* stdin */ - perror("dup2 stdin"); - if (dup2(inout[0], 1) < 0) /* stdout. Note: same socket as stdin. */ - perror("dup2 stdout"); - if (dup2(err[0], 2) < 0) /* stderr */ - perror("dup2 stderr"); -#endif /* USE_PIPES */ - - /* Do processing for the child (exec command etc). */ - do_child(command, pw, NULL, display, auth_proto, auth_data, NULL); - /* NOTREACHED */ - } - if (pid < 0) - packet_disconnect("fork failed: %.100s", strerror(errno)); -#ifdef USE_PIPES - /* We are the parent. Close the child sides of the pipes. */ - close(pin[0]); - close(pout[1]); - close(perr[1]); - - /* Enter the interactive session. */ - server_loop(pid, pin[1], pout[0], perr[0]); - /* server_loop has closed pin[1], pout[1], and perr[1]. */ -#else /* USE_PIPES */ - /* We are the parent. Close the child sides of the socket pairs. */ - close(inout[0]); - close(err[0]); - - /* - * Enter the interactive session. Note: server_loop must be able to - * handle the case that fdin and fdout are the same. - */ - server_loop(pid, inout[1], inout[1], err[1]); - /* server_loop has closed inout[1] and err[1]. */ -#endif /* USE_PIPES */ -} - -/* - * This is called to fork and execute a command when we have a tty. This - * will call do_child from the child, and server_loop from the parent after - * setting up file descriptors, controlling tty, updating wtmp, utmp, - * lastlog, and other such operations. - */ -void -do_exec_pty(const char *command, int ptyfd, int ttyfd, - const char *ttyname, struct passwd * pw, const char *term, - const char *display, const char *auth_proto, - const char *auth_data) -{ - int pid, fdout; - int ptymaster; - const char *hostname; - time_t last_login_time; - char buf[100], *time_string; - FILE *f; - char line[256]; - struct stat st; - int quiet_login; - struct sockaddr_storage from; - socklen_t fromlen; - struct pty_cleanup_context cleanup_context; - - /* Get remote host name. */ - hostname = get_canonical_hostname(); - - /* - * Get the time when the user last logged in. Buf will be set to - * contain the hostname the last login was from. - */ - if (!options.use_login) { - last_login_time = get_last_login_time(pw->pw_uid, pw->pw_name, - buf, sizeof(buf)); - } - setproctitle("%s@%s", pw->pw_name, strrchr(ttyname, '/') + 1); - - /* Fork the child. */ - if ((pid = fork()) == 0) { - pid = getpid(); - - /* Child. Reinitialize the log because the pid has - changed. */ - log_init(av0, options.log_level, options.log_facility, log_stderr); - - /* Close the master side of the pseudo tty. */ - close(ptyfd); - - /* Make the pseudo tty our controlling tty. */ - pty_make_controlling_tty(&ttyfd, ttyname); - - /* Redirect stdin from the pseudo tty. */ - if (dup2(ttyfd, fileno(stdin)) < 0) - error("dup2 stdin failed: %.100s", strerror(errno)); - - /* Redirect stdout to the pseudo tty. */ - if (dup2(ttyfd, fileno(stdout)) < 0) - error("dup2 stdin failed: %.100s", strerror(errno)); - - /* Redirect stderr to the pseudo tty. */ - if (dup2(ttyfd, fileno(stderr)) < 0) - error("dup2 stdin failed: %.100s", strerror(errno)); - - /* Close the extra descriptor for the pseudo tty. */ - close(ttyfd); - - /* - * Get IP address of client. This is needed because we want - * to record where the user logged in from. If the - * connection is not a socket, let the ip address be 0.0.0.0. - */ - memset(&from, 0, sizeof(from)); - if (packet_get_connection_in() == packet_get_connection_out()) { - fromlen = sizeof(from); - if (getpeername(packet_get_connection_in(), - (struct sockaddr *) & from, &fromlen) < 0) { - debug("getpeername: %.100s", strerror(errno)); - fatal_cleanup(); - } - } - /* Record that there was a login on that terminal. */ - record_login(pid, ttyname, pw->pw_name, pw->pw_uid, hostname, - (struct sockaddr *)&from); - - /* Check if .hushlogin exists. */ - snprintf(line, sizeof line, "%.200s/.hushlogin", pw->pw_dir); - quiet_login = stat(line, &st) >= 0; - - /* - * If the user has logged in before, display the time of last - * login. However, don't display anything extra if a command - * has been specified (so that ssh can be used to execute - * commands on a remote machine without users knowing they - * are going to another machine). Login(1) will do this for - * us as well, so check if login(1) is used - */ - if (command == NULL && last_login_time != 0 && !quiet_login && - !options.use_login) { - /* Convert the date to a string. */ - time_string = ctime(&last_login_time); - /* Remove the trailing newline. */ - if (strchr(time_string, '\n')) - *strchr(time_string, '\n') = 0; - /* Display the last login time. Host if displayed - if known. */ - if (strcmp(buf, "") == 0) - printf("Last login: %s\r\n", time_string); - else - printf("Last login: %s from %s\r\n", time_string, buf); - } - /* - * Print /etc/motd unless a command was specified or printing - * it was disabled in server options or login(1) will be - * used. Note that some machines appear to print it in - * /etc/profile or similar. - */ - if (command == NULL && options.print_motd && !quiet_login && - !options.use_login) { - /* Print /etc/motd if it exists. */ - f = fopen("/etc/motd", "r"); - if (f) { - while (fgets(line, sizeof(line), f)) - fputs(line, stdout); - fclose(f); - } - } - /* Do common processing for the child, such as execing the command. */ - do_child(command, pw, term, display, auth_proto, auth_data, ttyname); - /* NOTREACHED */ - } - if (pid < 0) - packet_disconnect("fork failed: %.100s", strerror(errno)); - /* Parent. Close the slave side of the pseudo tty. */ - close(ttyfd); - - /* - * Add a cleanup function to clear the utmp entry and record logout - * time in case we call fatal() (e.g., the connection gets closed). - */ - cleanup_context.pid = pid; - cleanup_context.ttyname = ttyname; - fatal_add_cleanup(pty_cleanup_proc, (void *) &cleanup_context); - fatal_remove_cleanup(pty_release_proc, (void *) ttyname); - - /* - * Create another descriptor of the pty master side for use as the - * standard input. We could use the original descriptor, but this - * simplifies code in server_loop. The descriptor is bidirectional. - */ - fdout = dup(ptyfd); - if (fdout < 0) - packet_disconnect("dup #1 failed: %.100s", strerror(errno)); - - /* we keep a reference to the pty master */ - ptymaster = dup(ptyfd); - if (ptymaster < 0) - packet_disconnect("dup #2 failed: %.100s", strerror(errno)); - - /* Enter interactive session. */ - server_loop(pid, ptyfd, fdout, -1); - /* server_loop _has_ closed ptyfd and fdout. */ - - /* Cancel the cleanup function. */ - fatal_remove_cleanup(pty_cleanup_proc, (void *) &cleanup_context); - - /* Record that the user has logged out. */ - record_logout(pid, ttyname); - - /* Release the pseudo-tty. */ - pty_release(ttyname); - - /* - * Close the server side of the socket pairs. We must do this after - * the pty cleanup, so that another process doesn't get this pty - * while we're still cleaning up. - */ - if (close(ptymaster) < 0) - error("close(ptymaster): %s", strerror(errno)); -} - -/* - * Sets the value of the given variable in the environment. If the variable - * already exists, its value is overriden. - */ -void -child_set_env(char ***envp, unsigned int *envsizep, const char *name, - const char *value) -{ - unsigned int i, namelen; - char **env; - - /* - * Find the slot where the value should be stored. If the variable - * already exists, we reuse the slot; otherwise we append a new slot - * at the end of the array, expanding if necessary. - */ - env = *envp; - namelen = strlen(name); - for (i = 0; env[i]; i++) - if (strncmp(env[i], name, namelen) == 0 && env[i][namelen] == '=') - break; - if (env[i]) { - /* Reuse the slot. */ - xfree(env[i]); - } else { - /* New variable. Expand if necessary. */ - if (i >= (*envsizep) - 1) { - (*envsizep) += 50; - env = (*envp) = xrealloc(env, (*envsizep) * sizeof(char *)); - } - /* Need to set the NULL pointer at end of array beyond the new slot. */ - env[i + 1] = NULL; - } - - /* Allocate space and format the variable in the appropriate slot. */ - env[i] = xmalloc(strlen(name) + 1 + strlen(value) + 1); - snprintf(env[i], strlen(name) + 1 + strlen(value) + 1, "%s=%s", name, value); -} - -/* - * Reads environment variables from the given file and adds/overrides them - * into the environment. If the file does not exist, this does nothing. - * Otherwise, it must consist of empty lines, comments (line starts with '#') - * and assignments of the form name=value. No other forms are allowed. - */ -void -read_environment_file(char ***env, unsigned int *envsize, - const char *filename) -{ - FILE *f; - char buf[4096]; - char *cp, *value; - - f = fopen(filename, "r"); - if (!f) - return; - - while (fgets(buf, sizeof(buf), f)) { - for (cp = buf; *cp == ' ' || *cp == '\t'; cp++) - ; - if (!*cp || *cp == '#' || *cp == '\n') - continue; - if (strchr(cp, '\n')) - *strchr(cp, '\n') = '\0'; - value = strchr(cp, '='); - if (value == NULL) { - fprintf(stderr, "Bad line in %.100s: %.200s\n", filename, buf); - continue; - } - /* Replace the equals sign by nul, and advance value to the value string. */ - *value = '\0'; - value++; - child_set_env(env, envsize, cp, value); - } - fclose(f); -} - -/* - * Performs common processing for the child, such as setting up the - * environment, closing extra file descriptors, setting the user and group - * ids, and executing the command or shell. - */ -void -do_child(const char *command, struct passwd * pw, const char *term, - const char *display, const char *auth_proto, - const char *auth_data, const char *ttyname) -{ - const char *shell, *cp = NULL; - char buf[256]; - FILE *f; - unsigned int envsize, i; - char **env; - extern char **environ; - struct stat st; - char *argv[10]; - - f = fopen("/etc/nologin", "r"); - if (f) { - /* /etc/nologin exists. Print its contents and exit. */ - while (fgets(buf, sizeof(buf), f)) - fputs(buf, stderr); - fclose(f); - if (pw->pw_uid != 0) - exit(254); - } - /* Set login name in the kernel. */ - if (setlogin(pw->pw_name) < 0) - error("setlogin failed: %s", strerror(errno)); - - /* Set uid, gid, and groups. */ - /* Login(1) does this as well, and it needs uid 0 for the "-h" - switch, so we let login(1) to this for us. */ - if (!options.use_login) { - if (getuid() == 0 || geteuid() == 0) { - if (setgid(pw->pw_gid) < 0) { - perror("setgid"); - exit(1); - } - /* Initialize the group list. */ - if (initgroups(pw->pw_name, pw->pw_gid) < 0) { - perror("initgroups"); - exit(1); - } - endgrent(); - - /* Permanently switch to the desired uid. */ - permanently_set_uid(pw->pw_uid); - } - if (getuid() != pw->pw_uid || geteuid() != pw->pw_uid) - fatal("Failed to set uids to %d.", (int) pw->pw_uid); - } - /* - * Get the shell from the password data. An empty shell field is - * legal, and means /bin/sh. - */ - shell = (pw->pw_shell[0] == '\0') ? _PATH_BSHELL : pw->pw_shell; - -#ifdef AFS - /* Try to get AFS tokens for the local cell. */ - if (k_hasafs()) { - char cell[64]; - - if (k_afs_cell_of_file(pw->pw_dir, cell, sizeof(cell)) == 0) - krb_afslog(cell, 0); - - krb_afslog(0, 0); - } -#endif /* AFS */ - - /* Initialize the environment. */ - envsize = 100; - env = xmalloc(envsize * sizeof(char *)); - env[0] = NULL; - - if (!options.use_login) { - /* Set basic environment. */ - child_set_env(&env, &envsize, "USER", pw->pw_name); - child_set_env(&env, &envsize, "LOGNAME", pw->pw_name); - child_set_env(&env, &envsize, "HOME", pw->pw_dir); - child_set_env(&env, &envsize, "PATH", _PATH_STDPATH); - - snprintf(buf, sizeof buf, "%.200s/%.50s", - _PATH_MAILDIR, pw->pw_name); - child_set_env(&env, &envsize, "MAIL", buf); - - /* Normal systems set SHELL by default. */ - child_set_env(&env, &envsize, "SHELL", shell); - } - if (getenv("TZ")) - child_set_env(&env, &envsize, "TZ", getenv("TZ")); - - /* Set custom environment options from RSA authentication. */ - while (custom_environment) { - struct envstring *ce = custom_environment; - char *s = ce->s; - int i; - for (i = 0; s[i] != '=' && s[i]; i++); - if (s[i] == '=') { - s[i] = 0; - child_set_env(&env, &envsize, s, s + i + 1); - } - custom_environment = ce->next; - xfree(ce->s); - xfree(ce); - } - - snprintf(buf, sizeof buf, "%.50s %d %d", - get_remote_ipaddr(), get_remote_port(), get_local_port()); - child_set_env(&env, &envsize, "SSH_CLIENT", buf); - - if (ttyname) - child_set_env(&env, &envsize, "SSH_TTY", ttyname); - if (term) - child_set_env(&env, &envsize, "TERM", term); - if (display) - child_set_env(&env, &envsize, "DISPLAY", display); - -#ifdef KRB4 - { - extern char *ticket; - - if (ticket) - child_set_env(&env, &envsize, "KRBTKFILE", ticket); - } -#endif /* KRB4 */ - - if (xauthfile) - child_set_env(&env, &envsize, "XAUTHORITY", xauthfile); - if (auth_get_socket_name() != NULL) - child_set_env(&env, &envsize, SSH_AUTHSOCKET_ENV_NAME, - auth_get_socket_name()); - - /* read $HOME/.ssh/environment. */ - if (!options.use_login) { - snprintf(buf, sizeof buf, "%.200s/.ssh/environment", pw->pw_dir); - read_environment_file(&env, &envsize, buf); - } - if (debug_flag) { - /* dump the environment */ - fprintf(stderr, "Environment:\n"); - for (i = 0; env[i]; i++) - fprintf(stderr, " %.200s\n", env[i]); - } - /* - * Close the connection descriptors; note that this is the child, and - * the server will still have the socket open, and it is important - * that we do not shutdown it. Note that the descriptors cannot be - * closed before building the environment, as we call - * get_remote_ipaddr there. - */ - if (packet_get_connection_in() == packet_get_connection_out()) - close(packet_get_connection_in()); - else { - close(packet_get_connection_in()); - close(packet_get_connection_out()); - } - /* - * Close all descriptors related to channels. They will still remain - * open in the parent. - */ - /* XXX better use close-on-exec? -markus */ - channel_close_all(); - - /* - * Close any extra file descriptors. Note that there may still be - * descriptors left by system functions. They will be closed later. - */ - endpwent(); - - /* - * Close any extra open file descriptors so that we don\'t have them - * hanging around in clients. Note that we want to do this after - * initgroups, because at least on Solaris 2.3 it leaves file - * descriptors open. - */ - for (i = 3; i < 64; i++) - close(i); - - /* Change current directory to the user\'s home directory. */ - if (chdir(pw->pw_dir) < 0) - fprintf(stderr, "Could not chdir to home directory %s: %s\n", - pw->pw_dir, strerror(errno)); - - /* - * Must take new environment into use so that .ssh/rc, /etc/sshrc and - * xauth are run in the proper environment. - */ - environ = env; - - /* - * Run $HOME/.ssh/rc, /etc/sshrc, or xauth (whichever is found first - * in this order). - */ - if (!options.use_login) { - if (stat(SSH_USER_RC, &st) >= 0) { - if (debug_flag) - fprintf(stderr, "Running /bin/sh %s\n", SSH_USER_RC); - - f = popen("/bin/sh " SSH_USER_RC, "w"); - if (f) { - if (auth_proto != NULL && auth_data != NULL) - fprintf(f, "%s %s\n", auth_proto, auth_data); - pclose(f); - } else - fprintf(stderr, "Could not run %s\n", SSH_USER_RC); - } else if (stat(SSH_SYSTEM_RC, &st) >= 0) { - if (debug_flag) - fprintf(stderr, "Running /bin/sh %s\n", SSH_SYSTEM_RC); - - f = popen("/bin/sh " SSH_SYSTEM_RC, "w"); - if (f) { - if (auth_proto != NULL && auth_data != NULL) - fprintf(f, "%s %s\n", auth_proto, auth_data); - pclose(f); - } else - fprintf(stderr, "Could not run %s\n", SSH_SYSTEM_RC); - } -#ifdef XAUTH_PATH - else { - /* Add authority data to .Xauthority if appropriate. */ - if (auth_proto != NULL && auth_data != NULL) { - if (debug_flag) - fprintf(stderr, "Running %.100s add %.100s %.100s %.100s\n", - XAUTH_PATH, display, auth_proto, auth_data); - - f = popen(XAUTH_PATH " -q -", "w"); - if (f) { - fprintf(f, "add %s %s %s\n", display, auth_proto, auth_data); - pclose(f); - } else - fprintf(stderr, "Could not run %s -q -\n", XAUTH_PATH); - } - } -#endif /* XAUTH_PATH */ - - /* Get the last component of the shell name. */ - cp = strrchr(shell, '/'); - if (cp) - cp++; - else - cp = shell; - } - /* - * If we have no command, execute the shell. In this case, the shell - * name to be passed in argv[0] is preceded by '-' to indicate that - * this is a login shell. - */ - if (!command) { - if (!options.use_login) { - char buf[256]; - - /* - * Check for mail if we have a tty and it was enabled - * in server options. - */ - if (ttyname && options.check_mail) { - char *mailbox; - struct stat mailstat; - mailbox = getenv("MAIL"); - if (mailbox != NULL) { - if (stat(mailbox, &mailstat) != 0 || mailstat.st_size == 0) - printf("No mail.\n"); - else if (mailstat.st_mtime < mailstat.st_atime) - printf("You have mail.\n"); - else - printf("You have new mail.\n"); - } - } - /* Start the shell. Set initial character to '-'. */ - buf[0] = '-'; - strncpy(buf + 1, cp, sizeof(buf) - 1); - buf[sizeof(buf) - 1] = 0; - - /* Execute the shell. */ - argv[0] = buf; - argv[1] = NULL; - execve(shell, argv, env); - - /* Executing the shell failed. */ - perror(shell); - exit(1); - - } else { - /* Launch login(1). */ - - execl("/usr/bin/login", "login", "-h", get_remote_ipaddr(), - "-p", "-f", "--", pw->pw_name, NULL); - - /* Login couldn't be executed, die. */ - - perror("login"); - exit(1); - } - } - /* - * Execute the command using the user's shell. This uses the -c - * option to execute the command. - */ - argv[0] = (char *) cp; - argv[1] = "-c"; - argv[2] = (char *) command; - argv[3] = NULL; - execve(shell, argv, env); - perror(shell); - exit(1); -} diff --git a/usr.bin/ssh/sshd/Makefile b/usr.bin/ssh/sshd/Makefile index 3815b5a302b..cdb0f8659d3 100644 --- a/usr.bin/ssh/sshd/Makefile +++ b/usr.bin/ssh/sshd/Makefile @@ -7,7 +7,8 @@ BINDIR= /usr/sbin MAN= sshd.8 SRCS= sshd.c auth-rhosts.c auth-passwd.c auth-rsa.c auth-rh-rsa.c \ - pty.c log-server.c login.c servconf.c serverloop.c + pty.c log-server.c login.c servconf.c serverloop.c session.c \ + auth.c .include # for KERBEROS and AFS -- 2.20.1