=================================================================== RCS file: /cvsrepo/anoncvs/cvs/src/usr.bin/ssh/auth2.c,v retrieving revision 1.8 retrieving revision 1.8.2.2 diff -u -r1.8 -r1.8.2.2 --- src/usr.bin/ssh/auth2.c 2000/05/08 17:42:24 1.8 +++ src/usr.bin/ssh/auth2.c 2000/11/08 21:30:25 1.8.2.2 @@ -9,11 +9,6 @@ * 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. - * 3. All advertising materials mentioning features or use of this software - * must display the following acknowledgement: - * This product includes software developed by Markus Friedl. - * 4. The name of the author may not be used to endorse or promote products - * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES @@ -26,8 +21,9 @@ * (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: auth2.c,v 1.8 2000/05/08 17:42:24 markus Exp $"); +RCSID("$OpenBSD: auth2.c,v 1.8.2.2 2000/11/08 21:30:25 jason Exp $"); #include #include @@ -39,7 +35,6 @@ #include "pty.h" #include "packet.h" #include "buffer.h" -#include "cipher.h" #include "servconf.h" #include "compat.h" #include "channels.h" @@ -54,60 +49,84 @@ #include "dsa.h" #include "uidswap.h" +#include "auth-options.h" /* import */ extern ServerOptions options; extern unsigned char *session_id2; extern int session_id2_len; +static Authctxt *x_authctxt = NULL; +static int one = 1; + +typedef struct Authmethod Authmethod; +struct Authmethod { + char *name; + int (*userauth)(Authctxt *authctxt); + int *enabled; +}; + /* protocol */ -void input_service_request(int type, int plen); -void input_userauth_request(int type, int plen); -void protocol_error(int type, int plen); +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); -/* auth */ -int ssh2_auth_none(struct passwd *pw); -int ssh2_auth_password(struct passwd *pw); -int ssh2_auth_pubkey(struct passwd *pw, unsigned char *raw, unsigned int rlen); /* helper */ -struct passwd* auth_set_user(char *u, char *s); +Authmethod *authmethod_lookup(const char *name); +struct passwd *pwcopy(struct passwd *pw); int user_dsa_key_allowed(struct passwd *pw, Key *key); +char *authmethods_get(void); -typedef struct Authctxt Authctxt; -struct Authctxt { - char *user; - char *service; - struct passwd pw; - int valid; +/* auth */ +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.dsa_authentication}, + {"keyboard-interactive", + userauth_kbdint, + &options.kbd_interactive_authentication}, + {"password", + userauth_passwd, + &options.password_authentication}, + {NULL, NULL, NULL} }; -static Authctxt *authctxt = NULL; -static int userauth_success = 0; /* - * loop until userauth_success == TRUE + * loop until authctxt->success == TRUE */ void do_authentication2() { - /* turn off skey/kerberos, not supported by SSH2 */ -#ifdef SKEY - options.skey_authentication = 0; -#endif + Authctxt *authctxt = xmalloc(sizeof(*authctxt)); + memset(authctxt, 'a', sizeof(*authctxt)); + authctxt->valid = 0; + authctxt->attempt = 0; + authctxt->success = 0; + x_authctxt = authctxt; /*XXX*/ + #ifdef KRB4 + /* turn off kerberos, not supported by SSH2 */ options.kerberos_authentication = 0; #endif - dispatch_init(&protocol_error); dispatch_set(SSH2_MSG_SERVICE_REQUEST, &input_service_request); - dispatch_run(DISPATCH_BLOCK, &userauth_success); + dispatch_run(DISPATCH_BLOCK, &authctxt->success, authctxt); do_authenticated2(); } void -protocol_error(int type, int plen) +protocol_error(int type, int plen, void *ctxt) { log("auth: protocol error: type %d plen %d", type, plen); packet_start(SSH2_MSG_UNIMPLEMENTED); @@ -117,15 +136,19 @@ } void -input_service_request(int type, int plen) +input_service_request(int type, int plen, void *ctxt) { + Authctxt *authctxt = ctxt; unsigned int len; int accept = 0; char *service = packet_get_string(&len); packet_done(); + if (authctxt == NULL) + fatal("input_service_request: no authctxt"); + if (strcmp(service, "ssh-userauth") == 0) { - if (!userauth_success) { + if (!authctxt->success) { accept = 1; /* now we can handle user-auth requests */ dispatch_set(SSH2_MSG_USERAUTH_REQUEST, &input_userauth_request); @@ -146,50 +169,89 @@ } void -input_userauth_request(int type, int plen) +input_userauth_request(int type, int plen, void *ctxt) { - static void (*authlog) (const char *fmt,...) = verbose; - static int attempt = 0; - unsigned int len, rlen; + Authctxt *authctxt = ctxt; + Authmethod *m = NULL; + char *user, *service, *method; int authenticated = 0; - char *raw, *user, *service, *method, *authmsg = NULL; - struct passwd *pw; - if (++attempt == AUTH_FAIL_MAX) + if (authctxt == NULL) + fatal("input_userauth_request: no authctxt"); + if (authctxt->attempt++ >= AUTH_FAIL_MAX) packet_disconnect("too many failed userauth_requests"); - raw = packet_get_raw(&rlen); - if (plen != rlen) - fatal("plen != rlen"); - user = packet_get_string(&len); - service = packet_get_string(&len); - method = packet_get_string(&len); + user = packet_get_string(NULL); + service = packet_get_string(NULL); + method = packet_get_string(NULL); debug("userauth-request for user %s service %s method %s", user, service, method); + debug("attempt #%d", authctxt->attempt); - /* XXX we only allow the ssh-connection service */ - pw = auth_set_user(user, service); - if (pw && strcmp(service, "ssh-connection")==0) { - if (strcmp(method, "none") == 0) { - authenticated = ssh2_auth_none(pw); - } else if (strcmp(method, "password") == 0) { - authenticated = ssh2_auth_password(pw); - } else if (strcmp(method, "publickey") == 0) { - authenticated = ssh2_auth_pubkey(pw, raw, rlen); + if (authctxt->attempt == 1) { + /* 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); + authctxt->valid = 1; + debug2("input_userauth_request: setting up authctxt for %s", user); + } else { + log("input_userauth_request: illegal user %s", user); } + authctxt->user = xstrdup(user); + authctxt->service = xstrdup(service); + } 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; + } } - if (authenticated && pw && pw->pw_uid == 0 && !options.permit_root_login) { + + m = authmethod_lookup(method); + if (m != NULL) { + debug2("input_userauth_request: try method %s", method); + authenticated = m->userauth(authctxt); + } else { + debug2("input_userauth_request: unsupported method %s", method); + } + if (!authctxt->valid && authenticated == 1) { + log("input_userauth_request: INTERNAL ERROR: authenticated invalid user %s service %s", user, method); authenticated = 0; - log("ROOT LOGIN REFUSED FROM %.200s", - get_canonical_hostname()); } + /* Special handling for root */ + if (authenticated == 1 && + authctxt->valid && authctxt->pw->pw_uid == 0 && !options.permit_root_login) { + authenticated = 0; + log("ROOT LOGIN REFUSED FROM %.200s", get_canonical_hostname()); + } + + /* Log before sending the reply */ + userauth_log(authctxt, authenticated, method); + userauth_reply(authctxt, authenticated); + + xfree(service); + xfree(user); + xfree(method); +} + + +void +userauth_log(Authctxt *authctxt, int authenticated, char *method) +{ + void (*authlog) (const char *fmt,...) = verbose; + char *user = NULL, *authmsg = NULL; + /* Raise logging level */ if (authenticated == 1 || - attempt == AUTH_FAIL_LOG || + !authctxt->valid || + authctxt->attempt >= AUTH_FAIL_LOG || strcmp(method, "password") == 0) authlog = log; - /* Log before sending the reply */ if (authenticated == 1) { authmsg = "Accepted"; } else if (authenticated == 0) { @@ -197,13 +259,24 @@ } else { authmsg = "Postponed"; } + + if (authctxt->valid) { + user = authctxt->pw->pw_uid == 0 ? "ROOT" : authctxt->user; + } else { + user = "NOUSER"; + } + authlog("%s %s for %.200s from %.200s port %d ssh2", - authmsg, - method, - pw && pw->pw_uid == 0 ? "ROOT" : user, - get_remote_ipaddr(), - get_remote_port()); + authmsg, + method, + user, + get_remote_ipaddr(), + get_remote_port()); +} +void +userauth_reply(Authctxt *authctxt, int authenticated) +{ /* XXX todo: check if multiple auth methods are needed */ if (authenticated == 1) { /* turn off userauth */ @@ -212,28 +285,33 @@ packet_send(); packet_write_wait(); /* now we can break out */ - userauth_success = 1; + authctxt->success = 1; } else if (authenticated == 0) { + char *methods = authmethods_get(); packet_start(SSH2_MSG_USERAUTH_FAILURE); - packet_put_cstring("publickey,password"); /* XXX dynamic */ - packet_put_char(0); /* XXX partial success, unused */ + packet_put_cstring(methods); + packet_put_char(0); /* XXX partial success, unused */ packet_send(); packet_write_wait(); + xfree(methods); + } else { + /* do nothing, we did already send a reply */ } - - xfree(service); - xfree(user); - xfree(method); } int -ssh2_auth_none(struct passwd *pw) +userauth_none(Authctxt *authctxt) { + /* disable method "none", only allowed one time */ + Authmethod *m = authmethod_lookup("none"); + if (m != NULL) + m->enabled = NULL; packet_done(); - return auth_password(pw, ""); + return authctxt->valid ? auth_password(authctxt->pw, "") : 0; } + int -ssh2_auth_password(struct passwd *pw) +userauth_passwd(Authctxt *authctxt) { char *password; int authenticated = 0; @@ -244,16 +322,39 @@ log("password change not supported"); password = packet_get_string(&len); packet_done(); - if (options.password_authentication && - auth_password(pw, password) == 1) + if (authctxt->valid && + auth_password(authctxt->pw, password) == 1) authenticated = 1; memset(password, 0, len); xfree(password); return authenticated; } + int -ssh2_auth_pubkey(struct passwd *pw, unsigned char *raw, unsigned int rlen) +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); +#ifdef SKEY + /* XXX hardcoded, we should look at devs */ + if (options.skey_authentication != 0) + authenticated = auth2_skey(authctxt); +#endif + xfree(lang); + xfree(devs); + return authenticated; +} + +int +userauth_pubkey(Authctxt *authctxt) +{ Buffer b; Key *key; char *pkalg, *pkblob, *sig; @@ -261,19 +362,15 @@ int have_sig; int authenticated = 0; - if (options.dsa_authentication == 0) { - debug("pubkey auth disabled"); + if (!authctxt->valid) { + debug2("userauth_pubkey: disabled because of invalid user"); return 0; } - if (datafellows & SSH_BUG_PUBKEYAUTH) { - log("bug compatibility with ssh-2.0.13 pubkey not implemented"); - return 0; - } have_sig = packet_get_char(); pkalg = packet_get_string(&alen); if (strcmp(pkalg, KEX_DSS) != 0) { - xfree(pkalg); log("bad pkalg %s", pkalg); /*XXX*/ + xfree(pkalg); return 0; } pkblob = packet_get_string(&blen); @@ -283,24 +380,35 @@ sig = packet_get_string(&slen); packet_done(); buffer_init(&b); - buffer_append(&b, session_id2, session_id2_len); + 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); - if (slen + 4 > rlen) - fatal("bad rlen/slen"); - buffer_append(&b, raw, rlen - slen - 4); + buffer_put_cstring(&b, authctxt->user); + buffer_put_cstring(&b, + datafellows & SSH_BUG_PUBKEYAUTH ? + "ssh-userauth" : + authctxt->service); + buffer_put_cstring(&b, "publickey"); + buffer_put_char(&b, have_sig); + buffer_put_cstring(&b, KEX_DSS); + buffer_put_string(&b, pkblob, blen); #ifdef DEBUG_DSS buffer_dump(&b); #endif /* test for correct signature */ - if (user_dsa_key_allowed(pw, key) && + if (user_dsa_key_allowed(authctxt->pw, key) && dsa_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(); - debug("test key..."); - /* test whether pkalg/pkblob are acceptable */ + /* XXX fake reply and always send PK_OK ? */ /* * XXX this allows testing whether a user is allowed @@ -309,7 +417,7 @@ * if a user is not allowed to login. is this an * issue? -markus */ - if (user_dsa_key_allowed(pw, key)) { + if (user_dsa_key_allowed(authctxt->pw, key)) { packet_start(SSH2_MSG_USERAUTH_PK_OK); packet_put_string(pkalg, alen); packet_put_string(pkblob, blen); @@ -318,6 +426,8 @@ authenticated = -1; } } + if (authenticated != 1) + auth_clear_options(); key_free(key); } xfree(pkalg); @@ -325,50 +435,62 @@ return authenticated; } -/* set and get current user */ +/* get current user */ struct passwd* auth_get_user(void) { - return (authctxt != NULL && authctxt->valid) ? &authctxt->pw : NULL; + return (x_authctxt != NULL && x_authctxt->valid) ? x_authctxt->pw : NULL; } -struct passwd* -auth_set_user(char *u, char *s) +#define DELIM "," + +char * +authmethods_get(void) { - struct passwd *pw, *copy; + Authmethod *method = NULL; + unsigned int size = 0; + char *list; - if (authctxt == NULL) { - authctxt = xmalloc(sizeof(*authctxt)); - authctxt->valid = 0; - authctxt->user = xstrdup(u); - authctxt->service = xstrdup(s); - setproctitle("%s", u); - pw = getpwnam(u); - if (!pw || !allowed_user(pw)) { - log("auth_set_user: illegal user %s", u); - return NULL; + 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); } - copy = &authctxt->pw; - memset(copy, 0, sizeof(*copy)); - copy->pw_name = xstrdup(pw->pw_name); - copy->pw_passwd = xstrdup(pw->pw_passwd); - copy->pw_uid = pw->pw_uid; - copy->pw_gid = pw->pw_gid; - copy->pw_dir = xstrdup(pw->pw_dir); - copy->pw_shell = xstrdup(pw->pw_shell); - authctxt->valid = 1; - } else { - if (strcmp(u, authctxt->user) != 0 || - strcmp(s, authctxt->service) != 0) { - log("auth_set_user: missmatch: (%s,%s)!=(%s,%s)", - u, s, authctxt->user, authctxt->service); - return NULL; + } + 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); } } - return auth_get_user(); + return list; } +Authmethod * +authmethod_lookup(const char *name) +{ + Authmethod *method = NULL; + 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"); + return NULL; +} + /* return 1 if user allows given key */ int user_dsa_key_allowed(struct passwd *pw, Key *key) @@ -381,6 +503,9 @@ struct stat st; Key *found; + if (pw == NULL) + return 0; + /* Temporarily use the user's uid. */ temporarily_use_uid(pw->pw_uid); @@ -408,8 +533,10 @@ 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, "DSA authentication refused for %.100s: " - "bad ownership or modes for '%s'.", pw->pw_name, file); + 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 SSH_USER_PERMITTED_KEYS */ @@ -424,36 +551,55 @@ (st.st_uid != 0 && st.st_uid != pw->pw_uid) || (st.st_mode & 022) != 0) { snprintf(buf, sizeof buf, - "DSA authentication refused for %.100s: " + "%s authentication refused for %.100s: " "bad ownership or modes for '%s'.", - pw->pw_name, line); + key_type(key), pw->pw_name, line); fail = 1; break; } } } if (fail) { - log(buf); fclose(f); + log("%s",buf); restore_uid(); return 0; } } found_key = 0; - found = key_new(KEY_DSA); + found = key_new(key->type); while (fgets(line, sizeof(line), f)) { - char *cp; + 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; + bits = key_read(found, &cp); - if (bits == 0) - continue; - if (key_equal(found, key)) { + if (bits == 0) { + /* no key? check if there are options for this key */ + int quoted = 0; + 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++) + ; + bits = key_read(found, &cp); + if (bits == 0) { + /* still no key? advance to next line*/ + continue; + } + } + if (key_equal(found, key) && + auth_parse_options(pw, options, linenum) == 1) { found_key = 1; debug("matching key found: file %s, line %ld", file, linenum); @@ -464,4 +610,19 @@ fclose(f); key_free(found); return found_key; +} + +struct passwd * +pwcopy(struct passwd *pw) +{ + struct passwd *copy = xmalloc(sizeof(*copy)); + memset(copy, 0, sizeof(*copy)); + copy->pw_name = xstrdup(pw->pw_name); + copy->pw_passwd = xstrdup(pw->pw_passwd); + copy->pw_uid = pw->pw_uid; + copy->pw_gid = pw->pw_gid; + copy->pw_class = xstrdup(pw->pw_class); + copy->pw_dir = xstrdup(pw->pw_dir); + copy->pw_shell = xstrdup(pw->pw_shell); + return copy; }