X-Git-Url: http://andersk.mit.edu/gitweb/openssh.git/blobdiff_plain/76fbdd4725087b7c1538bbb6fd0b4edff91fac65..HEAD:/auth.c diff --git a/auth.c b/auth.c index 096fb32a..da87807a 100644 --- a/auth.c +++ b/auth.c @@ -1,3 +1,4 @@ +/* $OpenBSD: auth.c,v 1.83 2010/01/13 23:47:26 djm Exp $ */ /* * Copyright (c) 2000 Markus Friedl. All rights reserved. * @@ -23,34 +24,62 @@ */ #include "includes.h" -RCSID("$OpenBSD: auth.c,v 1.28 2001/10/03 10:01:20 markus Exp $"); +#include +#include +#include + +#include + +#include +#include +#ifdef HAVE_PATHS_H +# include +#endif +#include #ifdef HAVE_LOGIN_H #include #endif -#if defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) +#ifdef USE_SHADOW #include -#endif /* defined(HAVE_SHADOW_H) && !defined(DISABLE_SHADOW) */ - +#endif #ifdef HAVE_LIBGEN_H #include #endif +#include +#include +#include +#include #include "xmalloc.h" #include "match.h" #include "groupaccess.h" #include "log.h" +#include "buffer.h" #include "servconf.h" +#include "key.h" +#include "hostfile.h" #include "auth.h" #include "auth-options.h" #include "canohost.h" -#include "buffer.h" -#include "bufaux.h" #include "uidswap.h" -#include "tildexpand.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 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 @@ -65,53 +94,106 @@ int allowed_user(struct passwd * pw) { struct stat st; - const char *hostname = NULL, *ipaddr = NULL; - char *shell; - int i; -#ifdef WITH_AIXAUTHENTICATE - char *loginmsg; -#endif /* WITH_AIXAUTHENTICATE */ -#if !defined(USE_PAM) && defined(HAVE_SHADOW_H) && \ - !defined(DISABLE_SHADOW) && defined(HAS_SHADOW_EXPIRE) - struct spwd *spw; + const char *hostname = NULL, *ipaddr = NULL, *passwd = NULL; + char *shell, *tmp, *chroot_path; + 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 || !pw->pw_name) return 0; - spw = getspnam(pw->pw_name); - if (spw != NULL) { - int days = time(NULL) / 86400; +#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 account expiry */ - if ((spw->sp_expire >= 0) && (days > spw->sp_expire)) - return 0; + /* check for locked account */ + if (!options.use_pam && passwd && *passwd) { + int locked = 0; - /* Check password expiry */ - if ((spw->sp_lstchg >= 0) && (spw->sp_max >= 0) && - (days > (spw->sp_lstchg + spw->sp_max))) +#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; + } } -#else - /* Shouldn't be called if pw is NULL, but better safe than sorry... */ - if (!pw || !pw->pw_name) - return 0; -#endif /* * 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; + shell = xstrdup((pw->pw_shell[0] == '\0') ? + _PATH_BSHELL : pw->pw_shell); + + /* + * Amend shell if chroot is requested. + */ + if (options.chroot_directory != NULL && + strcasecmp(options.chroot_directory, "none") != 0) { + tmp = tilde_expand_filename(options.chroot_directory, + pw->pw_uid); + chroot_path = percent_expand(tmp, "h", pw->pw_dir, + "u", pw->pw_name, (char *)NULL); + xfree(tmp); + xasprintf(&tmp, "%s/%s", chroot_path, shell); + xfree(shell); + shell = tmp; + free(chroot_path); + } /* deny if shell does not exists or is not executable */ - if (stat(shell, &st) != 0) + if (stat(shell, &st) != 0) { + logit("User %.100s not allowed because shell %.100s does not exist", + pw->pw_name, shell); + xfree(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); + xfree(shell); return 0; + } + xfree(shell); - if (options.num_deny_users > 0 || options.num_allow_users > 0) { - hostname = get_canonical_hostname(options.reverse_mapping_check); + 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(); } @@ -119,8 +201,12 @@ allowed_user(struct passwd * pw) if (options.num_deny_users > 0) { for (i = 0; i < options.num_deny_users; i++) if (match_user(pw->pw_name, hostname, ipaddr, - options.deny_users[i])) + 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) { @@ -129,19 +215,28 @@ allowed_user(struct passwd * pw) 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; + } } if (options.num_deny_groups > 0 || options.num_allow_groups > 0) { /* Get the user's group access list (primary and supplementary) */ - if (ga_init(pw->pw_name, pw->pw_gid) == 0) + 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 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; } /* @@ -152,52 +247,38 @@ allowed_user(struct passwd * pw) 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; } ga_free(); } -#ifdef WITH_AIXAUTHENTICATE - if (loginrestrictions(pw->pw_name, S_RLOGIN, NULL, &loginmsg) != 0) { - if (loginmsg && *loginmsg) { - /* Remove embedded newlines (if any) */ - char *p; - for (p = loginmsg; *p; p++) { - if (*p == '\n') - *p = ' '; - } - /* Remove trailing newline */ - *--p = '\0'; - log("Login restricted for %s: %.100s", pw->pw_name, loginmsg); - } +#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; } -Authctxt * -authctxt_new(void) -{ - Authctxt *authctxt = xmalloc(sizeof(*authctxt)); - memset(authctxt, 0, sizeof(*authctxt)); - return authctxt; -} - 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 >= AUTH_FAIL_LOG || + authctxt->failures >= options.max_authtries / 2 || strcmp(method, "password") == 0) - authlog = log; + authlog = logit; if (authctxt->postponed) authmsg = "Postponed"; @@ -207,11 +288,29 @@ auth_log(Authctxt *authctxt, int authenticated, char *method, char *info) authlog("%s %s for %s%.100s from %.200s port %d%s", authmsg, method, - authctxt->valid ? "" : "illegal user ", - authctxt->valid && authctxt->pw->pw_uid == 0 ? "ROOT" : authctxt->user, + 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 } /* @@ -223,19 +322,18 @@ auth_root_allowed(char *method) switch (options.permit_root_login) { case PERMIT_YES: return 1; - break; case PERMIT_NO_PASSWD: if (strcmp(method, "password") != 0) return 1; break; case PERMIT_FORCED_ONLY: if (forced_command) { - log("Root login accepted for forced command."); + logit("Root login accepted for forced command."); return 1; } break; } - log("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr()); + logit("ROOT LOGIN REFUSED FROM %.200s", get_remote_ipaddr()); return 0; } @@ -247,64 +345,39 @@ auth_root_allowed(char *method) * * This returns a buffer allocated by xmalloc. */ -char * -expand_filename(const char *filename, struct passwd *pw) +static char * +expand_authorized_keys(const char *filename, struct passwd *pw) { - Buffer buffer; - char *file; - const char *cp; + char *file, ret[MAXPATHLEN]; + int i; - /* - * Build the filename string in the buffer by making the appropriate - * substitutions to the given file name. - */ - buffer_init(&buffer); - for (cp = filename; *cp; cp++) { - if (cp[0] == '%' && cp[1] == '%') { - buffer_append(&buffer, "%", 1); - cp++; - continue; - } - if (cp[0] == '%' && cp[1] == 'h') { - buffer_append(&buffer, pw->pw_dir, strlen(pw->pw_dir)); - cp++; - continue; - } - if (cp[0] == '%' && cp[1] == 'u') { - buffer_append(&buffer, pw->pw_name, - strlen(pw->pw_name)); - cp++; - continue; - } - buffer_append(&buffer, cp, 1); - } - buffer_append(&buffer, "\0", 1); + 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/' */ - file = xmalloc(MAXPATHLEN); - cp = buffer_ptr(&buffer); - if (*cp != '/') - snprintf(file, MAXPATHLEN, "%s/%s", pw->pw_dir, cp); - else - strlcpy(file, cp, MAXPATHLEN); - - buffer_free(&buffer); - return file; + 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_filename(options.authorized_keys_file, pw); + return expand_authorized_keys(options.authorized_keys_file, pw); } char * authorized_keys_file2(struct passwd *pw) { - return expand_filename(options.authorized_keys_file2, pw); + return expand_authorized_keys(options.authorized_keys_file2, pw); } /* return ok if key exists in sysfile or userfile */ @@ -315,7 +388,7 @@ check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host, Key *found; char *user_hostfile; struct stat st; - int host_status; + HostStatus host_status; /* Check if we know the host and its host key. */ found = key_new(key->type); @@ -326,8 +399,8 @@ check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host, if (options.strict_modes && (stat(user_hostfile, &st) == 0) && ((st.st_uid != 0 && st.st_uid != pw->pw_uid) || - (st.st_mode & 022) != 0)) { - log("Authentication refused for %.100s: " + (st.st_mode & 022) != 0)) { + logit("Authentication refused for %.100s: " "bad owner or modes for %.200s", pw->pw_name, user_hostfile); } else { @@ -348,7 +421,7 @@ check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host, /* * Check a given file for security. This is defined as all components - * of the path to the file must either be owned by either the owner of + * 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 ? @@ -358,13 +431,14 @@ check_key_in_hostfiles(struct passwd *pw, Key *key, const char *host, * * Returns 0 on success and -1 on failure */ -int +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) { @@ -372,11 +446,8 @@ secure_filename(FILE *f, const char *file, struct passwd *pw, strerror(errno)); return -1; } - if (realpath(pw->pw_dir, homedir) == NULL) { - snprintf(err, errlen, "realpath %s failed: %s", pw->pw_dir, - 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 || @@ -399,13 +470,13 @@ secure_filename(FILE *f, const char *file, struct passwd *pw, if (stat(buf, &st) < 0 || (st.st_uid != 0 && st.st_uid != uid) || (st.st_mode & 022) != 0) { - snprintf(err, errlen, + snprintf(err, errlen, "bad ownership or modes for directory %s", buf); return -1; } - /* If are passed the homedir then we can stop */ - if (strcmp(homedir, buf) == 0) { + /* If are past the homedir then we can stop */ + if (comparehome && strcmp(homedir, buf) == 0) { debug3("secure_filename: terminating check at '%s'", buf); break; @@ -419,3 +490,157 @@ secure_filename(FILE *f, const char *file, struct passwd *pw, } 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) { + if (errno != ENOENT) + debug("Could not open keyfile '%s': %s", file, + strerror(errno)); + 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); +}