- markus@cvs.openbsd.org 2002/02/04 11:58:10
[auth2.c]
cross checking of announced vs actual pktype in pubkey/hostbaed auth; ok stevesk@
diff --git a/ChangeLog b/ChangeLog
index d16f607..2f39d6e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -81,6 +81,10 @@
- stevesk@cvs.openbsd.org 2002/02/04 00:53:39
[ssh-agent.c]
unneeded includes
+ - markus@cvs.openbsd.org 2002/02/04 11:58:10
+ [auth2.c]
+ cross checking of announced vs actual pktype in pubkey/hostbaed auth;
+ ok stevesk@
20020130
- (djm) Delay PRNG seeding until we need it in ssh-keygen, from markus@
@@ -7483,4 +7487,4 @@
- Wrote replacements for strlcpy and mkdtemp
- Released 1.0pre1
-$Id: ChangeLog,v 1.1821 2002/02/05 01:25:28 djm Exp $
+$Id: ChangeLog,v 1.1822 2002/02/05 01:26:03 djm Exp $
diff --git a/auth2.c b/auth2.c
index 6d91dea..08f7191 100644
--- a/auth2.c
+++ b/auth2.c
@@ -23,7 +23,7 @@
*/
#include "includes.h"
-RCSID("$OpenBSD: auth2.c,v 1.83 2002/01/29 14:32:03 markus Exp $");
+RCSID("$OpenBSD: auth2.c,v 1.84 2002/02/04 11:58:10 markus Exp $");
#include <openssl/evp.h>
@@ -397,7 +397,7 @@
userauth_pubkey(Authctxt *authctxt)
{
Buffer b;
- Key *key;
+ Key *key = NULL;
char *pkalg, *pkblob, *sig;
u_int alen, blen, slen;
int have_sig, pktype;
@@ -424,72 +424,80 @@
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;
+ log("userauth_pubkey: unsupported public key algorithm: %s",
+ pkalg);
+ goto done;
}
key = key_from_blob(pkblob, blen);
- if (key != NULL) {
- if (have_sig) {
- sig = packet_get_string(&slen);
- packet_check_eom();
- 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, pkalg);
- }
- 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_check_eom();
-
- /* 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);
+ if (key == NULL) {
+ error("userauth_pubkey: cannot decode key: %s", pkalg);
+ goto done;
}
+ if (key->type != pktype) {
+ error("userauth_pubkey: type mismatch for decoded key "
+ "(received %d, expected %d)", key->type, pktype);
+ goto done;
+ }
+ if (have_sig) {
+ sig = packet_get_string(&slen);
+ packet_check_eom();
+ 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, pkalg);
+ }
+ 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_check_eom();
+
+ /* 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();
+done:
debug2("userauth_pubkey: authenticated %d pkalg %s", authenticated, pkalg);
+ if (key != NULL)
+ key_free(key);
xfree(pkalg);
xfree(pkblob);
#ifdef HAVE_CYGWIN
@@ -503,7 +511,7 @@
userauth_hostbased(Authctxt *authctxt)
{
Buffer b;
- Key *key;
+ Key *key = NULL;
char *pkalg, *pkblob, *sig, *cuser, *chost, *service;
u_int alen, blen, slen;
int pktype;
@@ -537,7 +545,12 @@
}
key = key_from_blob(pkblob, blen);
if (key == NULL) {
- debug("userauth_hostbased: cannot decode key: %s", pkalg);
+ error("userauth_hostbased: cannot decode key: %s", pkalg);
+ goto done;
+ }
+ if (key->type != pktype) {
+ error("userauth_hostbased: type mismatch for decoded key "
+ "(received %d, expected %d)", key->type, pktype);
goto done;
}
service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
@@ -562,10 +575,10 @@
authenticated = 1;
buffer_clear(&b);
- key_free(key);
-
done:
debug2("userauth_hostbased: authenticated %d", authenticated);
+ if (key != NULL)
+ key_free(key);
xfree(pkalg);
xfree(pkblob);
xfree(cuser);