--- /dev/null
+/*
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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);
+}
--- /dev/null
+/*
+ * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, 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));
+}
*/
#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 <ssl/dh.h>
+#include <ssl/bn.h>
+#include <ssl/hmac.h>
+#include <ssl/dsa.h>
+#include <ssl/rsa.h>
+#include "key.h"
+
+#include "auth.h"
#ifdef LIBWRAP
#include <tcpd.h>
#define O_NOCTTY 0
#endif
-/* Local Xauthority file. */
-static char *xauthfile = NULL;
-
/* Server configuration options. */
ServerOptions options;
* 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
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
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
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.
*/
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;
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
packet_set_nonblocking();
/* perform the key exchange */
- do_ssh_kex();
-
+ do_ssh1_kex();
/* authenticate user and start session */
do_authentication();
(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();
* SSH1 key exchange
*/
void
-do_ssh_kex()
+do_ssh1_kex()
{
int i, len;
int plen, slen;
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);
-}
projects / openbsd / commitdiff