*/
#include "includes.h"
-RCSID("$OpenBSD: auth2.c,v 1.43 2001/02/22 21:59:44 markus Exp $");
+RCSID("$OpenBSD: auth2.c,v 1.82 2002/01/13 17:57:37 markus Exp $");
#include <openssl/evp.h>
#include "uidswap.h"
#include "auth-options.h"
#include "misc.h"
+#include "hostfile.h"
+#include "canohost.h"
+#include "match.h"
/* import */
extern ServerOptions options;
extern u_char *session_id2;
extern int session_id2_len;
-#ifdef WITH_AIXAUTHENTICATE
-extern char *aixloginmsg;
-#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, u_int32_t, void *);
+static void input_userauth_request(int, u_int32_t, void *);
/* helper */
-Authmethod *authmethod_lookup(const char *name);
-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",
{"keyboard-interactive",
userauth_kbdint,
&options.kbd_interactive_authentication},
+ {"hostbased",
+ userauth_hostbased,
+ &options.hostbased_authentication},
{NULL, NULL, NULL}
};
*/
void
-do_authentication2()
+do_authentication2(void)
{
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;
+ if (options.pam_authentication_via_kbd_int)
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();
+ do_authenticated(authctxt);
}
-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;
char *service = packet_get_string(&len);
- packet_done();
+ packet_check_eom();
if (authctxt == NULL)
fatal("input_service_request: no authctxt");
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;
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);
+ auth2_challenge_stop(authctxt);
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);
/* 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, &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) {
+#ifdef WITH_AIXAUTHENTICATE
+ loginfailed(authctxt->user,
+ get_canonical_hostname(options.reverse_mapping_check),
+ "ssh");
+#endif /* WITH_AIXAUTHENTICATE */
+ 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 */
Authmethod *m = authmethod_lookup("none");
if (m != NULL)
m->enabled = NULL;
- packet_done();
+ packet_check_eom();
userauth_banner();
if (authctxt->valid == 0)
return(0);
#ifdef HAVE_CYGWIN
- if (check_nt_auth(1, authctxt->pw->pw_uid) == 0)
+ if (check_nt_auth(1, authctxt->pw) == 0)
return(0);
#endif
#ifdef USE_PAM
#endif /* USE_PAM */
}
-int
+static int
userauth_passwd(Authctxt *authctxt)
{
char *password;
if (change)
log("password change not supported");
password = packet_get_string(&len);
- packet_done();
+ packet_check_eom();
if (authctxt->valid &&
#ifdef HAVE_CYGWIN
- check_nt_auth(1, authctxt->pw->pw_uid) &&
+ check_nt_auth(1, authctxt->pw) &&
#endif
#ifdef USE_PAM
auth_pam_password(authctxt->pw, password) == 1)
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();
+ packet_check_eom();
- 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)
+ if (check_nt_auth(0, authctxt->pw) == 0)
return(0);
#endif
return authenticated;
}
-int
+static int
userauth_pubkey(Authctxt *authctxt)
{
Buffer b;
if (key != NULL) {
if (have_sig) {
sig = packet_get_string(&slen);
- packet_done();
+ packet_check_eom();
buffer_init(&b);
if (datafellows & SSH_OLD_SESSIONID) {
buffer_append(&b, session_id2, session_id2_len);
} 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
xfree(sig);
} else {
debug("test whether pkalg/pkblob are acceptable");
- packet_done();
+ packet_check_eom();
/* XXX fake reply and always send PK_OK ? */
/*
xfree(pkalg);
xfree(pkblob);
#ifdef HAVE_CYGWIN
- if (check_nt_auth(0, authctxt->pw->pw_uid) == 0)
+ if (check_nt_auth(0, authctxt->pw) == 0)
return(0);
#endif
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;
- u_int size = 0;
+ Buffer b;
char *list;
+ buffer_init(&b);
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)
- continue;
- if (method->enabled != NULL && *(method->enabled) != 0) {
- if (list[0] != '\0')
- strlcat(list, DELIM, size);
- strlcat(list, method->name, size);
+ if (buffer_len(&b) > 0)
+ buffer_append(&b, ",", 1);
+ buffer_append(&b, method->name, strlen(method->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;
}
/* 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;
struct stat st;
Key *found;
+ char *fp;
if (pw == NULL)
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 (!*cp || *cp == '\n' || *cp == '#')
continue;
- if (key_read(found, &cp) == -1) {
+ 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);
/* Skip remaining whitespace. */
for (; *cp == ' ' || *cp == '\t'; cp++)
;
- if (key_read(found, &cp) == -1) {
+ 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",
+ debug("matching key found: file %s, line %lu",
file, linenum);
+ fp = key_fingerprint(found, SSH_FP_MD5, SSH_FP_HEX);
+ verbose("Found matching %s key: %s",
+ key_type(found), fp);
+ xfree(fp);
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;
+ HostStatus host_status;
+ int 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);
+}
+
andersk / openssh.git / blobdiff