*/
#include "includes.h"
-RCSID("$OpenBSD: auth2.c,v 1.42 2001/02/13 22:49:40 markus Exp $");
-
-#include <openssl/evp.h>
+RCSID("$OpenBSD: auth2.c,v 1.107 2004/07/28 09:40:29 markus Exp $");
#include "ssh2.h"
#include "xmalloc.h"
-#include "rsa.h"
-#include "sshpty.h"
#include "packet.h"
-#include "buffer.h"
#include "log.h"
#include "servconf.h"
#include "compat.h"
-#include "channels.h"
-#include "bufaux.h"
#include "auth.h"
-#include "session.h"
#include "dispatch.h"
-#include "key.h"
-#include "cipher.h"
-#include "kex.h"
#include "pathnames.h"
-#include "uidswap.h"
-#include "auth-options.h"
+#include "monitor_wrap.h"
+#include "buffer.h"
+
+#ifdef GSSAPI
+#include "ssh-gss.h"
+#endif
/* import */
extern ServerOptions options;
extern u_char *session_id2;
-extern int session_id2_len;
-
-#ifdef WITH_AIXAUTHENTICATE
-extern char *aixloginmsg;
+extern u_int session_id2_len;
+extern Buffer loginmsg;
+
+/* methods */
+
+extern Authmethod method_none;
+extern Authmethod method_pubkey;
+extern Authmethod method_passwd;
+extern Authmethod method_kbdint;
+extern Authmethod method_hostbased;
+#ifdef GSSAPI
+extern Authmethod method_gssapi;
#endif
-static Authctxt *x_authctxt = NULL;
-static int one = 1;
-
-typedef struct Authmethod Authmethod;
-struct Authmethod {
- char *name;
- int (*userauth)(Authctxt *authctxt);
- int *enabled;
+Authmethod *authmethods[] = {
+ &method_none,
+ &method_pubkey,
+#ifdef GSSAPI
+ &method_gssapi,
+#endif
+ &method_passwd,
+ &method_kbdint,
+ &method_hostbased,
+ NULL
};
/* 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, u_int32_t, void *);
+static void input_userauth_request(int, u_int32_t, 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);
-
-/* 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);
-
-Authmethod authmethods[] = {
- {"none",
- userauth_none,
- &one},
- {"publickey",
- userauth_pubkey,
- &options.pubkey_authentication},
- {"password",
- userauth_passwd,
- &options.password_authentication},
- {"keyboard-interactive",
- userauth_kbdint,
- &options.kbd_interactive_authentication},
- {NULL, NULL, NULL}
-};
+static Authmethod *authmethod_lookup(const char *);
+static char *authmethods_get(void);
+int user_key_allowed(struct passwd *, Key *);
/*
* loop until authctxt->success == TRUE
*/
void
-do_authentication2()
+do_authentication2(Authctxt *authctxt)
{
- Authctxt *authctxt = authctxt_new();
-
- x_authctxt = authctxt; /*XXX*/
-
- /* challenge-reponse is implemented via keyboard interactive */
- if (options.challenge_reponse_authentication)
+ /* challenge-response is implemented via keyboard interactive */
+ if (options.challenge_response_authentication)
options.kbd_interactive_authentication = 1;
- dispatch_init(&protocol_error);
+ dispatch_init(&dispatch_protocol_error);
dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request);
dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt);
- do_authenticated2(authctxt);
-}
-
-void
-protocol_error(int type, int plen, void *ctxt)
-{
- log("auth: protocol error: type %d plen %d", type, plen);
- packet_start(SSH2_MSG_UNIMPLEMENTED);
- packet_put_int(0);
- packet_send();
- packet_write_wait();
}
-void
-input_service_request(int type, int plen, void *ctxt)
+static void
+input_service_request(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
u_int len;
- int accept = 0;
+ int acceptit = 0;
char *service = packet_get_string(&len);
- packet_done();
+ packet_check_eom();
if (authctxt == NULL)
fatal("input_service_request: no authctxt");
if (strcmp(service, "ssh-userauth") == 0) {
if (!authctxt->success) {
- accept = 1;
+ acceptit = 1;
/* now we can handle user-auth requests */
dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request);
}
}
/* XXX all other service requests are denied */
- if (accept) {
+ if (acceptit) {
packet_start(SSH2_MSG_SERVICE_ACCEPT);
packet_put_cstring(service);
packet_send();
xfree(service);
}
-void
-input_userauth_request(int type, int plen, void *ctxt)
+static void
+input_userauth_request(int type, u_int32_t seq, void *ctxt)
{
Authctxt *authctxt = ctxt;
Authmethod *m = NULL;
if (authctxt->attempt++ == 0) {
/* setup auth context */
- struct passwd *pw = NULL;
- pw = getpwnam(user);
- if (pw && allowed_user(pw) && strcmp(service, "ssh-connection")==0) {
- authctxt->pw = pwcopy(pw);
+ authctxt->pw = PRIVSEP(getpwnamallow(user));
+ authctxt->user = xstrdup(user);
+ if (authctxt->pw && strcmp(service, "ssh-connection")==0) {
authctxt->valid = 1;
debug2("input_userauth_request: setting up authctxt for %s", user);
#ifdef USE_PAM
- start_pam(pw->pw_name);
+ if (options.use_pam)
+ PRIVSEP(start_pam(authctxt));
#endif
} else {
- log("input_userauth_request: illegal user %s", user);
+ logit("input_userauth_request: invalid user %s", user);
+ authctxt->pw = fakepw();
#ifdef USE_PAM
- start_pam("NOUSER");
+ if (options.use_pam)
+ PRIVSEP(start_pam(authctxt));
+#endif
+#ifdef SSH_AUDIT_EVENTS
+ PRIVSEP(audit_event(SSH_INVALID_USER));
#endif
}
- setproctitle("%s", pw ? user : "unknown");
- authctxt->user = xstrdup(user);
+ setproctitle("%s%s", authctxt->valid ? user : "unknown",
+ use_privsep ? " [net]" : "");
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;
+ if (use_privsep)
+ mm_inform_authserv(service, style);
+ } 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;
- }
+ auth2_challenge_stop(authctxt);
+
+#ifdef GSSAPI
+ dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, NULL);
+ dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE, NULL);
#endif
+ authctxt->postponed = 0;
+
/* try to authenticate user */
m = authmethod_lookup(method);
if (m != NULL) {
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(method))
+ !auth_root_allowed(method)) {
authenticated = 0;
+#ifdef SSH_AUDIT_EVENTS
+ PRIVSEP(audit_event(SSH_LOGIN_ROOT_DENIED));
+#endif
+ }
#ifdef USE_PAM
- if (authenticated && authctxt->user && !do_pam_account(authctxt->user,
- NULL))
+ if (options.use_pam && authenticated) {
+ if (!PRIVSEP(do_pam_account())) {
+ /* if PAM returned a message, send it to the user */
+ if (buffer_len(&loginmsg) > 0) {
+ buffer_append(&loginmsg, "\0", 1);
+ userauth_send_banner(buffer_ptr(&loginmsg));
+ packet_write_wait();
+ }
+ fatal("Access denied for user %s by PAM account "
+ "configuration", authctxt->user);
+ }
+ }
+#endif
+
+#ifdef _UNICOS
+ if (authenticated && cray_access_denied(authctxt->user)) {
authenticated = 0;
-#endif /* USE_PAM */
+ fatal("Access denied for user %s.",authctxt->user);
+ }
+#endif /* _UNICOS */
/* Log before sending the reply */
auth_log(authctxt, authenticated, method, " ssh2");
- if (!authctxt->postponed)
- userauth_reply(authctxt, authenticated);
-
- xfree(service);
- xfree(user);
- xfree(method);
-}
-
-void
-userauth_banner(void)
-{
- struct stat st;
- char *banner = NULL;
- off_t len, n;
- int fd;
-
- if (options.banner == NULL || (datafellows & SSH_BUG_BANNER))
+ if (authctxt->postponed)
return;
- if ((fd = open(options.banner, O_RDONLY)) < 0) {
- error("userauth_banner: open %s failed: %s",
- options.banner, strerror(errno));
- return;
- }
- if (fstat(fd, &st) < 0)
- goto done;
- len = st.st_size;
- banner = xmalloc(len + 1);
- if ((n = read(fd, banner, len)) < 0)
- goto done;
- banner[n] = '\0';
- packet_start(SSH2_MSG_USERAUTH_BANNER);
- packet_put_cstring(banner);
- packet_put_cstring(""); /* language, unused */
- packet_send();
- debug("userauth_banner: sent");
-done:
- if (banner)
- xfree(banner);
- close(fd);
- 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);
+ dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &dispatch_protocol_ignore);
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)
+ if (authctxt->failures++ > options.max_authtries) {
+#ifdef SSH_AUDIT_EVENTS
+ PRIVSEP(audit_event(SSH_LOGIN_EXCEED_MAXTRIES));
+#endif
packet_disconnect(AUTH_FAIL_MSG, authctxt->user);
+ }
methods = authmethods_get();
packet_start(SSH2_MSG_USERAUTH_FAILURE);
packet_put_cstring(methods);
}
}
-int
-userauth_none(Authctxt *authctxt)
-{
- /* disable method "none", only allowed one time */
- Authmethod *m = authmethod_lookup("none");
- if (m != NULL)
- m->enabled = NULL;
- packet_done();
- userauth_banner();
-
- if (authctxt->valid == 0)
- return(0);
-
-#ifdef HAVE_CYGWIN
- if (check_nt_auth(1, authctxt->pw->pw_uid) == 0)
- return(0);
-#endif
-#ifdef USE_PAM
- return auth_pam_password(authctxt->pw, "");
-#elif defined(HAVE_OSF_SIA)
- return 0;
-#else /* !HAVE_OSF_SIA && !USE_PAM */
- return auth_password(authctxt, "");
-#endif /* USE_PAM */
-}
-
-int
-userauth_passwd(Authctxt *authctxt)
-{
- char *password;
- int authenticated = 0;
- int change;
- u_int len;
- change = packet_get_char();
- if (change)
- log("password change not supported");
- password = packet_get_string(&len);
- packet_done();
- if (authctxt->valid &&
-#ifdef HAVE_CYGWIN
- check_nt_auth(1, authctxt->pw->pw_uid) &&
-#endif
-#ifdef USE_PAM
- auth_pam_password(authctxt->pw, password) == 1)
-#elif defined(HAVE_OSF_SIA)
- auth_sia_password(authctxt->user, password) == 1)
-#else /* !USE_PAM && !HAVE_OSF_SIA */
- auth_password(authctxt, password) == 1)
-#endif /* USE_PAM */
- authenticated = 1;
- memset(password, 0, len);
- xfree(password);
- return authenticated;
-}
-
-int
-userauth_kbdint(Authctxt *authctxt)
-{
- int authenticated = 0;
- char *lang = NULL;
- char *devs = NULL;
-
- lang = packet_get_string(NULL);
- devs = packet_get_string(NULL);
- packet_done();
-
- debug("keyboard-interactive language %s devs %s", lang, devs);
-
- if (options.challenge_reponse_authentication)
- authenticated = auth2_challenge(authctxt, devs);
-
-#ifdef USE_PAM
- if (authenticated == 0)
- authenticated = auth2_pam(authctxt);
-#endif
- xfree(lang);
- xfree(devs);
-#ifdef HAVE_CYGWIN
- if (check_nt_auth(0, authctxt->pw->pw_uid) == 0)
- return(0);
-#endif
- return authenticated;
-}
-
-int
-userauth_pubkey(Authctxt *authctxt)
-{
- Buffer b;
- Key *key;
- char *pkalg, *pkblob, *sig;
- u_int alen, blen, slen;
- int have_sig, pktype;
- int authenticated = 0;
-
- if (!authctxt->valid) {
- debug2("userauth_pubkey: disabled because of invalid user");
- return 0;
- }
- have_sig = packet_get_char();
- if (datafellows & SSH_BUG_PKAUTH) {
- debug2("userauth_pubkey: SSH_BUG_PKAUTH");
- /* no explicit pkalg given */
- pkblob = packet_get_string(&blen);
- buffer_init(&b);
- buffer_append(&b, pkblob, blen);
- /* so we have to extract the pkalg from the pkblob */
- pkalg = buffer_get_string(&b, &alen);
- buffer_free(&b);
- } else {
- pkalg = packet_get_string(&alen);
- pkblob = packet_get_string(&blen);
- }
- pktype = key_type_from_name(pkalg);
- if (pktype == KEY_UNSPEC) {
- /* this is perfectly legal */
- log("userauth_pubkey: unsupported public key algorithm: %s", pkalg);
- xfree(pkalg);
- xfree(pkblob);
- return 0;
- }
- key = key_from_blob(pkblob, blen);
- if (key != NULL) {
- if (have_sig) {
- sig = packet_get_string(&slen);
- packet_done();
- buffer_init(&b);
- if (datafellows & SSH_OLD_SESSIONID) {
- buffer_append(&b, session_id2, session_id2_len);
- } else {
- 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,
- datafellows & SSH_BUG_PKSERVICE ?
- "ssh-userauth" :
- authctxt->service);
- if (datafellows & SSH_BUG_PKAUTH) {
- buffer_put_char(&b, have_sig);
- } else {
- buffer_put_cstring(&b, "publickey");
- buffer_put_char(&b, have_sig);
- buffer_put_cstring(&b, key_ssh_name(key));
- }
- buffer_put_string(&b, pkblob, blen);
-#ifdef DEBUG_PK
- buffer_dump(&b);
-#endif
- /* test for correct signature */
- if (user_key_allowed(authctxt->pw, key) &&
- key_verify(key, sig, slen, buffer_ptr(&b), buffer_len(&b)) == 1)
- authenticated = 1;
- buffer_clear(&b);
- xfree(sig);
- } else {
- debug("test whether pkalg/pkblob are acceptable");
- packet_done();
-
- /* XXX fake reply and always send PK_OK ? */
- /*
- * XXX this allows testing whether a user is allowed
- * to login: if you happen to have a valid pubkey this
- * message is sent. the message is NEVER sent at all
- * if a user is not allowed to login. is this an
- * issue? -markus
- */
- if (user_key_allowed(authctxt->pw, key)) {
- packet_start(SSH2_MSG_USERAUTH_PK_OK);
- packet_put_string(pkalg, alen);
- packet_put_string(pkblob, blen);
- packet_send();
- packet_write_wait();
- authctxt->postponed = 1;
- }
- }
- if (authenticated != 1)
- auth_clear_options();
- key_free(key);
- }
- debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
- xfree(pkalg);
- xfree(pkblob);
-#ifdef HAVE_CYGWIN
- if (check_nt_auth(0, authctxt->pw->pw_uid) == 0)
- return(0);
-#endif
- return authenticated;
-}
-
-/* get current user */
-
-struct passwd*
-auth_get_user(void)
-{
- return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL;
-}
-
#define DELIM ","
-char *
+static char *
authmethods_get(void)
{
- Authmethod *method = NULL;
- u_int size = 0;
+ Buffer b;
char *list;
+ int i;
- for (method = authmethods; method->name != NULL; method++) {
- if (strcmp(method->name, "none") == 0)
- continue;
- if (method->enabled != NULL && *(method->enabled) != 0) {
- if (size != 0)
- size += strlen(DELIM);
- size += strlen(method->name);
- }
- }
- size++; /* trailing '\0' */
- list = xmalloc(size);
- list[0] = '\0';
-
- for (method = authmethods; method->name != NULL; method++) {
- if (strcmp(method->name, "none") == 0)
+ buffer_init(&b);
+ for (i = 0; authmethods[i] != NULL; i++) {
+ if (strcmp(authmethods[i]->name, "none") == 0)
continue;
- if (method->enabled != NULL && *(method->enabled) != 0) {
- if (list[0] != '\0')
- strlcat(list, DELIM, size);
- strlcat(list, method->name, size);
+ if (authmethods[i]->enabled != NULL &&
+ *(authmethods[i]->enabled) != 0) {
+ if (buffer_len(&b) > 0)
+ buffer_append(&b, ",", 1);
+ buffer_append(&b, authmethods[i]->name,
+ strlen(authmethods[i]->name));
}
}
+ buffer_append(&b, "\0", 1);
+ list = xstrdup(buffer_ptr(&b));
+ buffer_free(&b);
return list;
}
-Authmethod *
+static Authmethod *
authmethod_lookup(const char *name)
{
- Authmethod *method = NULL;
+ int i;
+
if (name != NULL)
- for (method = authmethods; method->name != NULL; method++)
- if (method->enabled != NULL &&
- *(method->enabled) != 0 &&
- strcmp(name, method->name) == 0)
- return method;
- debug2("Unrecognized authentication method name: %s", name ? name : "NULL");
+ for (i = 0; authmethods[i] != NULL; i++)
+ if (authmethods[i]->enabled != NULL &&
+ *(authmethods[i]->enabled) != 0 &&
+ strcmp(name, authmethods[i]->name) == 0)
+ return authmethods[i];
+ debug2("Unrecognized authentication method name: %s",
+ name ? name : "NULL");
return NULL;
}
-
-/* return 1 if user allows given key */
-int
-user_key_allowed(struct passwd *pw, Key *key)
-{
- char line[8192], file[MAXPATHLEN];
- int found_key = 0;
- FILE *f;
- u_long linenum = 0;
- struct stat st;
- Key *found;
-
- if (pw == NULL)
- return 0;
-
- /* Temporarily use the user's uid. */
- temporarily_use_uid(pw->pw_uid);
-
- /* The authorized keys. */
- snprintf(file, sizeof file, "%.500s/%.100s", pw->pw_dir,
- _PATH_SSH_USER_PERMITTED_KEYS2);
-
- /* Fail quietly if file does not exist */
- if (stat(file, &st) < 0) {
- /* Restore the privileged uid. */
- restore_uid();
- return 0;
- }
- /* Open the file containing the authorized keys. */
- f = fopen(file, "r");
- if (!f) {
- /* Restore the privileged uid. */
- 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;
- }
- }
- found_key = 0;
- found = key_new(key->type);
-
- while (fgets(line, sizeof(line), f)) {
- char *cp, *options = NULL;
- linenum++;
- /* Skip leading whitespace, empty and comment lines. */
- for (cp = line; *cp == ' ' || *cp == '\t'; cp++)
- ;
- if (!*cp || *cp == '\n' || *cp == '#')
- continue;
-
- if (key_read(found, &cp) == -1) {
- /* no key? check if there are options for this key */
- int quoted = 0;
- debug2("user_key_allowed: check options: '%s'", cp);
- options = cp;
- for (; *cp && (quoted || (*cp != ' ' && *cp != '\t')); cp++) {
- if (*cp == '\\' && cp[1] == '"')
- cp++; /* Skip both */
- else if (*cp == '"')
- quoted = !quoted;
- }
- /* Skip remaining whitespace. */
- for (; *cp == ' ' || *cp == '\t'; cp++)
- ;
- if (key_read(found, &cp) == -1) {
- debug2("user_key_allowed: advance: '%s'", cp);
- /* still no key? advance to next line*/
- continue;
- }
- }
- if (key_equal(found, key) &&
- auth_parse_options(pw, options, file, linenum) == 1) {
- found_key = 1;
- debug("matching key found: file %s, line %ld",
- file, linenum);
- break;
- }
- }
- restore_uid();
- fclose(f);
- key_free(found);
- return found_key;
-}