+/* $OpenBSD: auth.c,v 1.80 2008/11/04 07:58:09 djm Exp $ */
/*
- * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
- * All rights reserved
- * Copyright (c) 2000 Markus Friedl. All rights reserved.
+ * Copyright (c) 2000 Markus Friedl. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "includes.h"
-RCSID("$OpenBSD: auth.c,v 1.6 2000/04/26 21:28:31 markus Exp $");
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/param.h>
+
+#include <netinet/in.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#ifdef HAVE_PATHS_H
+# include <paths.h>
+#endif
+#include <pwd.h>
+#ifdef HAVE_LOGIN_H
+#include <login.h>
+#endif
+#ifdef USE_SHADOW
+#include <shadow.h>
+#endif
+#ifdef HAVE_LIBGEN_H
+#include <libgen.h>
+#endif
+#include <stdarg.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
#include "xmalloc.h"
-#include "rsa.h"
-#include "ssh.h"
-#include "pty.h"
-#include "packet.h"
+#include "match.h"
+#include "groupaccess.h"
+#include "log.h"
#include "buffer.h"
-#include "cipher.h"
-#include "mpaux.h"
#include "servconf.h"
-#include "compat.h"
-#include "channels.h"
-#include "match.h"
-
-#include "bufaux.h"
-#include "ssh2.h"
+#include "key.h"
+#include "hostfile.h"
#include "auth.h"
-#include "session.h"
-#include "dispatch.h"
-
+#include "auth-options.h"
+#include "canohost.h"
+#include "uidswap.h"
+#include "misc.h"
+#include "packet.h"
+#include "loginrec.h"
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
+#include "monitor_wrap.h"
/* import */
extern ServerOptions options;
-extern char *forced_command;
+extern int use_privsep;
+extern Buffer loginmsg;
+extern struct passwd *privsep_pw;
+
+/* Debugging messages */
+Buffer auth_debug;
+int auth_debug_init;
/*
- * 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.
+ * Check if the user is allowed to log in via ssh. If user is listed
+ * in DenyUsers or one of user's groups 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 one of user's groups isn't
+ * listed there, false will be returned.
* If the user's shell is not executable, false will be returned.
* Otherwise true is returned.
*/
allowed_user(struct passwd * pw)
{
struct stat st;
- struct group *grp;
- int i;
-#ifdef WITH_AIXAUTHENTICATE
- char *loginmsg;
-#endif /* WITH_AIXAUTHENTICATE */
+ const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL;
+ char *shell;
+ u_int i;
+#ifdef USE_SHADOW
+ struct spwd *spw = NULL;
+#endif
/* Shouldn't be called if pw is NULL, but better safe than sorry... */
- if (!pw)
+ if (!pw || !pw->pw_name)
+ return 0;
+
+#ifdef USE_SHADOW
+ if (!options.use_pam)
+ spw = getspnam(pw->pw_name);
+#ifdef HAS_SHADOW_EXPIRE
+ if (!options.use_pam && spw != NULL && auth_shadow_acctexpired(spw))
return 0;
+#endif /* HAS_SHADOW_EXPIRE */
+#endif /* USE_SHADOW */
+
+ /* grab passwd field for locked account check */
+ passwd = pw->pw_passwd;
+#ifdef USE_SHADOW
+ if (spw != NULL)
+#ifdef USE_LIBIAF
+ passwd = get_iaf_password(pw);
+#else
+ passwd = spw->sp_pwdp;
+#endif /* USE_LIBIAF */
+#endif
+
+ /* check for locked account */
+ if (!options.use_pam && passwd && *passwd) {
+ int locked = 0;
+
+#ifdef LOCKED_PASSWD_STRING
+ if (strcmp(passwd, LOCKED_PASSWD_STRING) == 0)
+ locked = 1;
+#endif
+#ifdef LOCKED_PASSWD_PREFIX
+ if (strncmp(passwd, LOCKED_PASSWD_PREFIX,
+ strlen(LOCKED_PASSWD_PREFIX)) == 0)
+ locked = 1;
+#endif
+#ifdef LOCKED_PASSWD_SUBSTR
+ if (strstr(passwd, LOCKED_PASSWD_SUBSTR))
+ locked = 1;
+#endif
+#ifdef USE_LIBIAF
+ free(passwd);
+#endif /* USE_LIBIAF */
+ if (locked) {
+ logit("User %.100s not allowed because account is locked",
+ pw->pw_name);
+ return 0;
+ }
+ }
+
+ /*
+ * 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;
/* deny if shell does not exists or is not executable */
- if (stat(pw->pw_shell, &st) != 0)
+ if (stat(shell, &st) != 0) {
+ logit("User %.100s not allowed because shell %.100s does not exist",
+ pw->pw_name, shell);
return 0;
- if (!((st.st_mode & S_IFREG) && (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP))))
+ }
+ if (S_ISREG(st.st_mode) == 0 ||
+ (st.st_mode & (S_IXOTH|S_IXUSR|S_IXGRP)) == 0) {
+ logit("User %.100s not allowed because shell %.100s is not executable",
+ pw->pw_name, shell);
return 0;
+ }
+
+ if (options.num_deny_users > 0 || options.num_allow_users > 0 ||
+ options.num_deny_groups > 0 || options.num_allow_groups > 0) {
+ hostname = get_canonical_hostname(options.use_dns);
+ ipaddr = get_remote_ipaddr();
+ }
/* 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]))
+ if (match_user(pw->pw_name, hostname, ipaddr,
+ options.deny_users[i])) {
+ logit("User %.100s from %.100s not allowed "
+ "because listed in DenyUsers",
+ pw->pw_name, hostname);
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]))
+ if (match_user(pw->pw_name, hostname, ipaddr,
+ options.allow_users[i]))
break;
/* i < options.num_allow_users iff we break for loop */
- if (i >= options.num_allow_users)
+ if (i >= options.num_allow_users) {
+ logit("User %.100s from %.100s not allowed because "
+ "not listed in AllowUsers", pw->pw_name, hostname);
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)
+ /* Get the user's group access list (primary and supplementary) */
+ if (ga_init(pw->pw_name, pw->pw_gid) == 0) {
+ logit("User %.100s from %.100s not allowed because "
+ "not in any group", pw->pw_name, hostname);
return 0;
+ }
- /* Return false if user's group is listed in DenyGroups */
- if (options.num_deny_groups > 0) {
- if (!grp->gr_name)
+ /* Return false if one of user's groups is listed in DenyGroups */
+ if (options.num_deny_groups > 0)
+ if (ga_match(options.deny_groups,
+ options.num_deny_groups)) {
+ ga_free();
+ logit("User %.100s from %.100s not allowed "
+ "because a group is listed in DenyGroups",
+ pw->pw_name, hostname);
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
+ * Return false if AllowGroups isn't empty and one of user's groups
* isn't listed there
*/
- if (options.num_allow_groups > 0) {
- if (!grp->gr_name)
+ if (options.num_allow_groups > 0)
+ if (!ga_match(options.allow_groups,
+ options.num_allow_groups)) {
+ ga_free();
+ logit("User %.100s from %.100s not allowed "
+ "because none of user's groups are listed "
+ "in AllowGroups", pw->pw_name, hostname);
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;
- }
+ }
+ ga_free();
}
-#ifdef WITH_AIXAUTHENTICATE
- if (loginrestrictions(pw->pw_name,S_LOGIN,NULL,&loginmsg) != 0)
+#ifdef CUSTOM_SYS_AUTH_ALLOWED_USER
+ if (!sys_auth_allowed_user(pw, &loginmsg))
return 0;
-#endif /* WITH_AIXAUTHENTICATE */
+#endif
/* We found no reason not to let this user try to log on... */
return 1;
}
+
+void
+auth_log(Authctxt *authctxt, int authenticated, char *method, char *info)
+{
+ void (*authlog) (const char *fmt,...) = verbose;
+ char *authmsg;
+
+ if (use_privsep && !mm_is_monitor() && !authctxt->postponed)
+ return;
+
+ /* Raise logging level */
+ if (authenticated == 1 ||
+ !authctxt->valid ||
+ authctxt->failures >= options.max_authtries / 2 ||
+ strcmp(method, "password") == 0)
+ authlog = logit;
+
+ if (authctxt->postponed)
+ authmsg = "Postponed";
+ else
+ authmsg = authenticated ? "Accepted" : "Failed";
+
+ authlog("%s %s for %s%.100s from %.200s port %d%s",
+ authmsg,
+ method,
+ authctxt->valid ? "" : "invalid user ",
+ authctxt->user,
+ get_remote_ipaddr(),
+ get_remote_port(),
+ info);
+
+#ifdef CUSTOM_FAILED_LOGIN
+ if (authenticated == 0 && !authctxt->postponed &&
+ (strcmp(method, "password") == 0 ||
+ strncmp(method, "keyboard-interactive", 20) == 0 ||
+ strcmp(method, "challenge-response") == 0))
+ record_failed_login(authctxt->user,
+ get_canonical_hostname(options.use_dns), "ssh");
+# ifdef WITH_AIXAUTHENTICATE
+ if (authenticated)
+ sys_auth_record_login(authctxt->user,
+ get_canonical_hostname(options.use_dns), "ssh", &loginmsg);
+# endif
+#endif
+#ifdef SSH_AUDIT_EVENTS
+ if (authenticated == 0 && !authctxt->postponed)
+ audit_event(audit_classify_auth(method));
+#endif
+}
+
+/*
+ * Check whether root logins are disallowed.
+ */
+int
+auth_root_allowed(char *method)
+{
+ switch (options.permit_root_login) {
+ case PERMIT_YES:
+ return 1;
+ case PERMIT_NO_PASSWD:
+ if (strcmp(method, "password") != 0)
+ return 1;
+ break;
+ case PERMIT_FORCED_ONLY:
+ if (forced_command) {
+ logit("Root login accepted for forced command.");
+ return 1;
+ }
+ break;
+ }
+ logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr());
+ return 0;
+}
+
+
+/*
+ * Given a template and a passwd structure, build a filename
+ * by substituting % tokenised options. Currently, %% becomes '%',
+ * %h becomes the home directory and %u the username.
+ *
+ * This returns a buffer allocated by xmalloc.
+ */
+static char *
+expand_authorized_keys(const char *filename, struct passwd *pw)
+{
+ char *file, ret[MAXPATHLEN];
+ int i;
+
+ file = percent_expand(filename, "h", pw->pw_dir,
+ "u", pw->pw_name, (char *)NULL);
+
+ /*
+ * Ensure that filename starts anchored. If not, be backward
+ * compatible and prepend the '%h/'
+ */
+ if (*file == '/')
+ return (file);
+
+ i = snprintf(ret, sizeof(ret), "%s/%s", pw->pw_dir, file);
+ if (i < 0 || (size_t)i >= sizeof(ret))
+ fatal("expand_authorized_keys: path too long");
+ xfree(file);
+ return (xstrdup(ret));
+}
+
+char *
+authorized_keys_file(struct passwd *pw)
+{
+ return expand_authorized_keys(options.authorized_keys_file, pw);
+}
+
+char *
+authorized_keys_file2(struct passwd *pw)
+{
+ return expand_authorized_keys(options.authorized_keys_file2, pw);
+}
+
+/* return ok if key exists in sysfile or userfile */
+HostStatus
+check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host,
+ const char *sysfile, const char *userfile)
+{
+ Key *found;
+ char *user_hostfile;
+ struct stat st;
+ HostStatus host_status;
+
+ /* Check if we know the host and its host key. */
+ found = key_new(key->type);
+ host_status = check_host_in_hostfile(sysfile, host, key, found, NULL);
+
+ if (host_status != HOST_OK && userfile != NULL) {
+ user_hostfile = tilde_expand_filename(userfile, pw->pw_uid);
+ if (options.strict_modes &&
+ (stat(user_hostfile, &st) == 0) &&
+ ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
+ (st.st_mode & 022) != 0)) {
+ logit("Authentication refused for %.100s: "
+ "bad owner or modes for %.200s",
+ pw->pw_name, user_hostfile);
+ } else {
+ temporarily_use_uid(pw);
+ host_status = check_host_in_hostfile(user_hostfile,
+ host, key, found, NULL);
+ restore_uid();
+ }
+ xfree(user_hostfile);
+ }
+ key_free(found);
+
+ debug2("check_key_in_hostfiles: key %s for %s", host_status == HOST_OK ?
+ "ok" : "not found", host);
+ return host_status;
+}
+
+
+/*
+ * Check a given file for security. This is defined as all components
+ * of the path to the file must be owned by either the owner of
+ * of the file or root and no directories must be group or world writable.
+ *
+ * XXX Should any specific check be done for sym links ?
+ *
+ * Takes an open file descriptor, the file name, a uid and and
+ * error buffer plus max size as arguments.
+ *
+ * Returns 0 on success and -1 on failure
+ */
+static int
+secure_filename(FILE *f, const char *file, struct passwd *pw,
+ char *err, size_t errlen)
+{
+ uid_t uid = pw->pw_uid;
+ char buf[MAXPATHLEN], homedir[MAXPATHLEN];
+ char *cp;
+ int comparehome = 0;
+ struct stat st;
+
+ if (realpath(file, buf) == NULL) {
+ snprintf(err, errlen, "realpath %s failed: %s", file,
+ strerror(errno));
+ return -1;
+ }
+ if (realpath(pw->pw_dir, homedir) != NULL)
+ comparehome = 1;
+
+ /* check the open file to avoid races */
+ if (fstat(fileno(f), &st) < 0 ||
+ (st.st_uid != 0 && st.st_uid != uid) ||
+ (st.st_mode & 022) != 0) {
+ snprintf(err, errlen, "bad ownership or modes for file %s",
+ buf);
+ return -1;
+ }
+
+ /* for each component of the canonical path, walking upwards */
+ for (;;) {
+ if ((cp = dirname(buf)) == NULL) {
+ snprintf(err, errlen, "dirname() failed");
+ return -1;
+ }
+ strlcpy(buf, cp, sizeof(buf));
+
+ debug3("secure_filename: checking '%s'", buf);
+ if (stat(buf, &st) < 0 ||
+ (st.st_uid != 0 && st.st_uid != uid) ||
+ (st.st_mode & 022) != 0) {
+ snprintf(err, errlen,
+ "bad ownership or modes for directory %s", buf);
+ return -1;
+ }
+
+ /* If are passed the homedir then we can stop */
+ if (comparehome && strcmp(homedir, buf) == 0) {
+ debug3("secure_filename: terminating check at '%s'",
+ buf);
+ break;
+ }
+ /*
+ * dirname should always complete with a "/" path,
+ * but we can be paranoid and check for "." too
+ */
+ if ((strcmp("/", buf) == 0) || (strcmp(".", buf) == 0))
+ break;
+ }
+ return 0;
+}
+
+FILE *
+auth_openkeyfile(const char *file, struct passwd *pw, int strict_modes)
+{
+ char line[1024];
+ struct stat st;
+ int fd;
+ FILE *f;
+
+ /*
+ * Open the file containing the authorized keys
+ * Fail quietly if file does not exist
+ */
+ if ((fd = open(file, O_RDONLY|O_NONBLOCK)) == -1)
+ return NULL;
+
+ if (fstat(fd, &st) < 0) {
+ close(fd);
+ return NULL;
+ }
+ if (!S_ISREG(st.st_mode)) {
+ logit("User %s authorized keys %s is not a regular file",
+ pw->pw_name, file);
+ close(fd);
+ return NULL;
+ }
+ unset_nonblock(fd);
+ if ((f = fdopen(fd, "r")) == NULL) {
+ close(fd);
+ return NULL;
+ }
+ if (options.strict_modes &&
+ secure_filename(f, file, pw, line, sizeof(line)) != 0) {
+ fclose(f);
+ logit("Authentication refused: %s", line);
+ return NULL;
+ }
+
+ return f;
+}
+
+struct passwd *
+getpwnamallow(const char *user)
+{
+#ifdef HAVE_LOGIN_CAP
+ extern login_cap_t *lc;
+#ifdef BSD_AUTH
+ auth_session_t *as;
+#endif
+#endif
+ struct passwd *pw;
+
+ parse_server_match_config(&options, user,
+ get_canonical_hostname(options.use_dns), get_remote_ipaddr());
+
+ pw = getpwnam(user);
+ if (pw == NULL) {
+ logit("Invalid user %.100s from %.100s",
+ user, get_remote_ipaddr());
+#ifdef CUSTOM_FAILED_LOGIN
+ record_failed_login(user,
+ get_canonical_hostname(options.use_dns), "ssh");
+#endif
+#ifdef SSH_AUDIT_EVENTS
+ audit_event(SSH_INVALID_USER);
+#endif /* SSH_AUDIT_EVENTS */
+ return (NULL);
+ }
+ if (!allowed_user(pw))
+ return (NULL);
+#ifdef HAVE_LOGIN_CAP
+ if ((lc = login_getclass(pw->pw_class)) == NULL) {
+ debug("unable to get login class: %s", user);
+ return (NULL);
+ }
+#ifdef BSD_AUTH
+ if ((as = auth_open()) == NULL || auth_setpwd(as, pw) != 0 ||
+ auth_approval(as, lc, pw->pw_name, "ssh") <= 0) {
+ debug("Approval failure for %s", user);
+ pw = NULL;
+ }
+ if (as != NULL)
+ auth_close(as);
+#endif
+#endif
+ if (pw != NULL)
+ return (pwcopy(pw));
+ return (NULL);
+}
+
+void
+auth_debug_add(const char *fmt,...)
+{
+ char buf[1024];
+ va_list args;
+
+ if (!auth_debug_init)
+ return;
+
+ va_start(args, fmt);
+ vsnprintf(buf, sizeof(buf), fmt, args);
+ va_end(args);
+ buffer_put_cstring(&auth_debug, buf);
+}
+
+void
+auth_debug_send(void)
+{
+ char *msg;
+
+ if (!auth_debug_init)
+ return;
+ while (buffer_len(&auth_debug)) {
+ msg = buffer_get_string(&auth_debug, NULL);
+ packet_send_debug("%s", msg);
+ xfree(msg);
+ }
+}
+
+void
+auth_debug_reset(void)
+{
+ if (auth_debug_init)
+ buffer_clear(&auth_debug);
+ else {
+ buffer_init(&auth_debug);
+ auth_debug_init = 1;
+ }
+}
+
+struct passwd *
+fakepw(void)
+{
+ static struct passwd fake;
+
+ memset(&fake, 0, sizeof(fake));
+ fake.pw_name = "NOUSER";
+ fake.pw_passwd =
+ "$2a$06$r3.juUaHZDlIbQaO2dS9FuYxL1W9M81R1Tc92PoSNmzvpEqLkLGrK";
+ fake.pw_gecos = "NOUSER";
+ fake.pw_uid = privsep_pw == NULL ? (uid_t)-1 : privsep_pw->pw_uid;
+ fake.pw_gid = privsep_pw == NULL ? (gid_t)-1 : privsep_pw->pw_gid;
+#ifdef HAVE_PW_CLASS_IN_PASSWD
+ fake.pw_class = "";
+#endif
+ fake.pw_dir = "/nonexist";
+ fake.pw_shell = "/nonexist";
+
+ return (&fake);
+}
andersk / openssh.git / blobdiff