*/
#include "includes.h"
-RCSID("$OpenBSD: auth2.c,v 1.37 2001/02/07 22:35:46 markus Exp $");
-
-#ifdef HAVE_OSF_SIA
-# include <sia.h>
-# include <siad.h>
-#endif
+RCSID("$OpenBSD: auth2.c,v 1.69 2001/07/23 18:14:58 stevesk Exp $");
#include <openssl/evp.h>
#include "ssh2.h"
#include "xmalloc.h"
#include "rsa.h"
-#include "pty.h"
+#include "sshpty.h"
#include "packet.h"
#include "buffer.h"
#include "log.h"
#include "pathnames.h"
#include "uidswap.h"
#include "auth-options.h"
+#include "misc.h"
+#include "hostfile.h"
+#include "canohost.h"
+#include "tildexpand.h"
+#include "match.h"
/* import */
extern ServerOptions options;
#ifdef WITH_AIXAUTHENTICATE
extern char *aixloginmsg;
#endif
-#ifdef HAVE_OSF_SIA
-extern int saved_argc;
-extern char **saved_argv;
-#endif
static Authctxt *x_authctxt = NULL;
static int one = 1;
/* protocol */
-void input_service_request(int type, int plen, void *ctxt);
-void input_userauth_request(int type, int plen, void *ctxt);
-void protocol_error(int type, int plen, void *ctxt);
+static void input_service_request(int, int, void *);
+static void input_userauth_request(int, int, void *);
+static void protocol_error(int, int, void *);
/* helper */
-Authmethod *authmethod_lookup(const char *name);
-struct passwd *pwcopy(struct passwd *pw);
-int user_key_allowed(struct passwd *pw, Key *key);
-char *authmethods_get(void);
+static Authmethod *authmethod_lookup(const char *);
+static char *authmethods_get(void);
+static int user_key_allowed(struct passwd *, Key *);
+static int hostbased_key_allowed(struct passwd *, const char *, char *, Key *);
/* auth */
-void userauth_banner(void);
-int userauth_none(Authctxt *authctxt);
-int userauth_passwd(Authctxt *authctxt);
-int userauth_pubkey(Authctxt *authctxt);
-int userauth_kbdint(Authctxt *authctxt);
+static void userauth_banner(void);
+static int userauth_none(Authctxt *);
+static int userauth_passwd(Authctxt *);
+static int userauth_pubkey(Authctxt *);
+static int userauth_hostbased(Authctxt *);
+static int userauth_kbdint(Authctxt *);
Authmethod authmethods[] = {
{"none",
{"publickey",
userauth_pubkey,
&options.pubkey_authentication},
- {"keyboard-interactive",
- userauth_kbdint,
- &options.kbd_interactive_authentication},
{"password",
userauth_passwd,
&options.password_authentication},
+ {"keyboard-interactive",
+ userauth_kbdint,
+ &options.kbd_interactive_authentication},
+ {"hostbased",
+ userauth_hostbased,
+ &options.hostbased_authentication},
{NULL, NULL, NULL}
};
x_authctxt = authctxt; /*XXX*/
/* challenge-reponse is implemented via keyboard interactive */
- if (options.challenge_reponse_authentication)
+ if (options.challenge_response_authentication)
+ options.kbd_interactive_authentication = 1;
+ if (options.pam_authentication_via_kbd_int)
options.kbd_interactive_authentication = 1;
dispatch_init(&protocol_error);
dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
- do_authenticated2(authctxt);
+ do_authenticated(authctxt);
}
-void
+static void
protocol_error(int type, int plen, void *ctxt)
{
log("auth: protocol error: type %d plen %d", type, plen);
packet_write_wait();
}
-void
+static void
input_service_request(int type, int plen, void *ctxt)
{
Authctxt *authctxt = ctxt;
xfree(service);
}
-void
+static void
input_userauth_request(int type, int plen, void *ctxt)
{
Authctxt *authctxt = ctxt;
if (authctxt->attempt++ == 0) {
/* setup auth context */
struct passwd *pw = NULL;
- setproctitle("%s", user);
pw = getpwnam(user);
if (pw && allowed_user(pw) && strcmp(service, "ssh-connection")==0) {
authctxt->pw = pwcopy(pw);
start_pam("NOUSER");
#endif
}
+ setproctitle("%s", pw ? user : "unknown");
authctxt->user = xstrdup(user);
authctxt->service = xstrdup(service);
- authctxt->style = style ? xstrdup(style) : NULL; /* currently unused */
- } else if (authctxt->valid) {
- if (strcmp(user, authctxt->user) != 0 ||
- strcmp(service, authctxt->service) != 0) {
- log("input_userauth_request: missmatch: (%s,%s)!=(%s,%s)",
- user, service, authctxt->user, authctxt->service);
- authctxt->valid = 0;
- }
+ authctxt->style = style ? xstrdup(style) : NULL;
+ } else if (strcmp(user, authctxt->user) != 0 ||
+ strcmp(service, authctxt->service) != 0) {
+ packet_disconnect("Change of username or service not allowed: "
+ "(%s,%s) -> (%s,%s)",
+ authctxt->user, authctxt->service, user, service);
}
/* reset state */
dispatch_set(SSH2_MSG_USERAUTH_INFO_RESPONSE, &protocol_error);
authctxt->postponed = 0;
+#ifdef BSD_AUTH
+ if (authctxt->as) {
+ auth_close(authctxt->as);
+ authctxt->as = NULL;
+ }
+#endif
/* try to authenticate user */
m = authmethod_lookup(method);
debug2("input_userauth_request: try method %s", method);
authenticated = m->userauth(authctxt);
}
+ userauth_finish(authctxt, authenticated, method);
+
+ xfree(service);
+ xfree(user);
+ xfree(method);
+}
+
+void
+userauth_finish(Authctxt *authctxt, int authenticated, char *method)
+{
+ char *methods;
+
if (!authctxt->valid && authenticated)
fatal("INTERNAL ERROR: authenticated invalid user %s",
authctxt->user);
/* Special handling for root */
- if (authenticated && authctxt->pw->pw_uid == 0 && !auth_root_allowed())
+ if (authenticated && authctxt->pw->pw_uid == 0 &&
+ !auth_root_allowed(method))
authenticated = 0;
#ifdef USE_PAM
- if (authenticated && authctxt->user && !do_pam_account(authctxt->user, NULL))
+ if (authenticated && authctxt->user && !do_pam_account(authctxt->user,
+ NULL))
authenticated = 0;
#endif /* USE_PAM */
/* Log before sending the reply */
auth_log(authctxt, authenticated, method, " ssh2");
- if (!authctxt->postponed)
- userauth_reply(authctxt, authenticated);
+ if (authctxt->postponed)
+ return;
- xfree(service);
- xfree(user);
- xfree(method);
+ /* XXX todo: check if multiple auth methods are needed */
+ if (authenticated == 1) {
+ /* turn off userauth */
+ dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error);
+ packet_start(SSH2_MSG_USERAUTH_SUCCESS);
+ packet_send();
+ packet_write_wait();
+ /* now we can break out */
+ authctxt->success = 1;
+ } else {
+ if (authctxt->failures++ > AUTH_FAIL_MAX)
+ packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
+ methods = authmethods_get();
+ packet_start(SSH2_MSG_USERAUTH_FAILURE);
+ packet_put_cstring(methods);
+ packet_put_char(0); /* XXX partial success, unused */
+ packet_send();
+ packet_write_wait();
+ xfree(methods);
+ }
}
-void
+static void
userauth_banner(void)
{
struct stat st;
if (options.banner == NULL || (datafellows & SSH_BUG_BANNER))
return;
- if ((fd = open(options.banner, O_RDONLY)) < 0) {
- error("userauth_banner: open %s failed: %s",
- options.banner, strerror(errno));
+ if ((fd = open(options.banner, O_RDONLY)) < 0)
return;
- }
if (fstat(fd, &st) < 0)
goto done;
len = st.st_size;
return;
}
-void
-userauth_reply(Authctxt *authctxt, int authenticated)
-{
- char *methods;
-
- /* XXX todo: check if multiple auth methods are needed */
- if (authenticated == 1) {
-#ifdef WITH_AIXAUTHENTICATE
- /* We don't have a pty yet, so just label the line as "ssh" */
- if (loginsuccess(authctxt->user?authctxt->user:"NOUSER",
- get_canonical_hostname(options.reverse_mapping_check),
- "ssh", &aixloginmsg) < 0)
- aixloginmsg = NULL;
-#endif /* WITH_AIXAUTHENTICATE */
- /* turn off userauth */
- dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &protocol_error);
- packet_start(SSH2_MSG_USERAUTH_SUCCESS);
- packet_send();
- packet_write_wait();
- /* now we can break out */
- authctxt->success = 1;
- } else {
- if (authctxt->failures++ > AUTH_FAIL_MAX)
- packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
- methods = authmethods_get();
- packet_start(SSH2_MSG_USERAUTH_FAILURE);
- packet_put_cstring(methods);
- packet_put_char(0); /* XXX partial success, unused */
- packet_send();
- packet_write_wait();
- xfree(methods);
- }
-}
-
-int
+static int
userauth_none(Authctxt *authctxt)
{
/* disable method "none", only allowed one time */
#ifdef USE_PAM
return auth_pam_password(authctxt->pw, "");
#elif defined(HAVE_OSF_SIA)
- return (sia_validate_user(NULL, saved_argc, saved_argv,
- get_canonical_hostname(options.reverse_mapping_check),
- authctxt->user?authctxt->user:"NOUSER", NULL, 0,
- NULL, "") == SIASUCCESS);
+ return 0;
#else /* !HAVE_OSF_SIA && !USE_PAM */
- return auth_password(authctxt->pw, "");
+ return auth_password(authctxt, "");
#endif /* USE_PAM */
}
-int
+static int
userauth_passwd(Authctxt *authctxt)
{
char *password;
#ifdef USE_PAM
auth_pam_password(authctxt->pw, password) == 1)
#elif defined(HAVE_OSF_SIA)
- sia_validate_user(NULL, saved_argc, saved_argv,
- get_canonical_hostname(options.reverse_mapping_check),
- authctxt->user?authctxt->user:"NOUSER", NULL, 0, NULL,
- password) == SIASUCCESS)
+ auth_sia_password(authctxt->user, password) == 1)
#else /* !USE_PAM && !HAVE_OSF_SIA */
- auth_password(authctxt->pw, password) == 1)
+ auth_password(authctxt, password) == 1)
#endif /* USE_PAM */
authenticated = 1;
memset(password, 0, len);
return authenticated;
}
-int
+static int
userauth_kbdint(Authctxt *authctxt)
{
int authenticated = 0;
- char *lang = NULL;
- char *devs = NULL;
+ char *lang, *devs;
lang = packet_get_string(NULL);
devs = packet_get_string(NULL);
packet_done();
- debug("keyboard-interactive language %s devs %s", lang, devs);
+ debug("keyboard-interactive devs %s", devs);
- if (options.challenge_reponse_authentication)
+ if (options.challenge_response_authentication)
authenticated = auth2_challenge(authctxt, devs);
#ifdef USE_PAM
- if (authenticated == 0)
+ if (authenticated == 0 && options.pam_authentication_via_kbd_int)
authenticated = auth2_pam(authctxt);
#endif
- xfree(lang);
xfree(devs);
+ xfree(lang);
#ifdef HAVE_CYGWIN
if (check_nt_auth(0, authctxt->pw->pw_uid) == 0)
return(0);
return authenticated;
}
-int
+static int
userauth_pubkey(Authctxt *authctxt)
{
Buffer b;
} else {
buffer_put_cstring(&b, "publickey");
buffer_put_char(&b, have_sig);
- buffer_put_cstring(&b, key_ssh_name(key));
+ buffer_put_cstring(&b, pkalg);
}
buffer_put_string(&b, pkblob, blen);
#ifdef DEBUG_PK
return authenticated;
}
+static int
+userauth_hostbased(Authctxt *authctxt)
+{
+ Buffer b;
+ Key *key;
+ char *pkalg, *pkblob, *sig, *cuser, *chost, *service;
+ u_int alen, blen, slen;
+ int pktype;
+ int authenticated = 0;
+
+ if (!authctxt->valid) {
+ debug2("userauth_hostbased: disabled because of invalid user");
+ return 0;
+ }
+ pkalg = packet_get_string(&alen);
+ pkblob = packet_get_string(&blen);
+ chost = packet_get_string(NULL);
+ cuser = packet_get_string(NULL);
+ sig = packet_get_string(&slen);
+
+ debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d",
+ cuser, chost, pkalg, slen);
+#ifdef DEBUG_PK
+ debug("signature:");
+ buffer_init(&b);
+ buffer_append(&b, sig, slen);
+ buffer_dump(&b);
+ buffer_free(&b);
+#endif
+ pktype = key_type_from_name(pkalg);
+ if (pktype == KEY_UNSPEC) {
+ /* this is perfectly legal */
+ log("userauth_hostbased: unsupported "
+ "public key algorithm: %s", pkalg);
+ goto done;
+ }
+ key = key_from_blob(pkblob, blen);
+ if (key == NULL) {
+ debug("userauth_hostbased: cannot decode key: %s", pkalg);
+ goto done;
+ }
+ service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
+ authctxt->service;
+ buffer_init(&b);
+ buffer_put_string(&b, session_id2, session_id2_len);
+ /* reconstruct packet */
+ buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
+ buffer_put_cstring(&b, authctxt->user);
+ buffer_put_cstring(&b, service);
+ buffer_put_cstring(&b, "hostbased");
+ buffer_put_string(&b, pkalg, alen);
+ buffer_put_string(&b, pkblob, blen);
+ buffer_put_cstring(&b, chost);
+ buffer_put_cstring(&b, cuser);
+#ifdef DEBUG_PK
+ buffer_dump(&b);
+#endif
+ /* test for allowed key and correct signature */
+ if (hostbased_key_allowed(authctxt->pw, cuser, chost, key) &&
+ key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
+ authenticated = 1;
+
+ buffer_clear(&b);
+ key_free(key);
+
+done:
+ debug2("userauth_hostbased: authenticated %d", authenticated);
+ xfree(pkalg);
+ xfree(pkblob);
+ xfree(cuser);
+ xfree(chost);
+ xfree(sig);
+ return authenticated;
+}
+
/* get current user */
struct passwd*
#define DELIM ","
-char *
+static char *
authmethods_get(void)
{
Authmethod *method = NULL;
return list;
}
-Authmethod *
+static Authmethod *
authmethod_lookup(const char *name)
{
Authmethod *method = NULL;
}
/* return 1 if user allows given key */
-int
-user_key_allowed(struct passwd *pw, Key *key)
+static int
+user_key_allowed2(struct passwd *pw, Key *key, char *file)
{
- char line[8192], file[MAXPATHLEN];
+ char line[8192];
int found_key = 0;
FILE *f;
u_long linenum = 0;
return 0;
/* Temporarily use the user's uid. */
- temporarily_use_uid(pw->pw_uid);
+ temporarily_use_uid(pw);
- /* The authorized keys. */
- snprintf(file, sizeof file, "%.500s/%.100s", pw->pw_dir,
- _PATH_SSH_USER_PERMITTED_KEYS2);
+ debug("trying public key file %s", file);
/* Fail quietly if file does not exist */
if (stat(file, &st) < 0) {
restore_uid();
return 0;
}
- if (options.strict_modes) {
- int fail = 0;
- char buf[1024];
- /* Check open file in order to avoid open/stat races */
- if (fstat(fileno(f), &st) < 0 ||
- (st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
- (st.st_mode & 022) != 0) {
- snprintf(buf, sizeof buf,
- "%s authentication refused for %.100s: "
- "bad ownership or modes for '%s'.",
- key_type(key), pw->pw_name, file);
- fail = 1;
- } else {
- /* Check path to _PATH_SSH_USER_PERMITTED_KEYS */
- int i;
- static const char *check[] = {
- "", _PATH_SSH_USER_DIR, NULL
- };
- for (i = 0; check[i]; i++) {
- snprintf(line, sizeof line, "%.500s/%.100s",
- pw->pw_dir, check[i]);
- if (stat(line, &st) < 0 ||
- (st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
- (st.st_mode & 022) != 0) {
- snprintf(buf, sizeof buf,
- "%s authentication refused for %.100s: "
- "bad ownership or modes for '%s'.",
- key_type(key), pw->pw_name, line);
- fail = 1;
- break;
- }
- }
- }
- if (fail) {
- fclose(f);
- log("%s",buf);
- restore_uid();
- return 0;
- }
+ if (options.strict_modes &&
+ secure_filename(f, file, pw, line, sizeof(line)) != 0) {
+ fclose(f);
+ log("Authentication refused: %s", line);
+ restore_uid();
+ return 0;
}
+
found_key = 0;
found = key_new(key->type);
if (key_equal(found, key) &&
auth_parse_options(pw, options, file, linenum) == 1) {
found_key = 1;
- debug("matching key found: file %s, line %ld",
+ debug("matching key found: file %s, line %lu",
file, linenum);
break;
}
restore_uid();
fclose(f);
key_free(found);
+ if (!found_key)
+ debug2("key not found");
return found_key;
}
+
+/* check whether given key is in .ssh/authorized_keys* */
+static int
+user_key_allowed(struct passwd *pw, Key *key)
+{
+ int success;
+ char *file;
+
+ file = authorized_keys_file(pw);
+ success = user_key_allowed2(pw, key, file);
+ xfree(file);
+ if (success)
+ return success;
+
+ /* try suffix "2" for backward compat, too */
+ file = authorized_keys_file2(pw);
+ success = user_key_allowed2(pw, key, file);
+ xfree(file);
+ return success;
+}
+
+/* return 1 if given hostkey is allowed */
+static int
+hostbased_key_allowed(struct passwd *pw, const char *cuser, char *chost,
+ Key *key)
+{
+ const char *resolvedname, *ipaddr, *lookup;
+ int host_status, len;
+
+ resolvedname = get_canonical_hostname(options.reverse_mapping_check);
+ ipaddr = get_remote_ipaddr();
+
+ debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s",
+ chost, resolvedname, ipaddr);
+
+ if (options.hostbased_uses_name_from_packet_only) {
+ if (auth_rhosts2(pw, cuser, chost, chost) == 0)
+ return 0;
+ lookup = chost;
+ } else {
+ if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') {
+ debug2("stripping trailing dot from chost %s", chost);
+ chost[len - 1] = '\0';
+ }
+ if (strcasecmp(resolvedname, chost) != 0)
+ log("userauth_hostbased mismatch: "
+ "client sends %s, but we resolve %s to %s",
+ chost, ipaddr, resolvedname);
+ if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0)
+ return 0;
+ lookup = resolvedname;
+ }
+ debug2("userauth_hostbased: access allowed by auth_rhosts2");
+
+ host_status = check_key_in_hostfiles(pw, key, lookup,
+ _PATH_SSH_SYSTEM_HOSTFILE,
+ options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
+
+ /* backward compat if no key has been found. */
+ if (host_status == HOST_NEW)
+ host_status = check_key_in_hostfiles(pw, key, lookup,
+ _PATH_SSH_SYSTEM_HOSTFILE2,
+ options.ignore_user_known_hosts ? NULL :
+ _PATH_SSH_USER_HOSTFILE2);
+
+ return (host_status == HOST_OK);
+}
+