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Annotation of src/usr.bin/ssh/auth-rh-rsa.c, Revision 1.12

1.1       provos      1: /*
1.9       deraadt     2:  *
                      3:  * auth-rh-rsa.c
                      4:  *
                      5:  * Author: Tatu Ylonen <ylo@cs.hut.fi>
                      6:  *
                      7:  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
                      8:  *                    All rights reserved
                      9:  *
                     10:  * Created: Sun May  7 03:08:06 1995 ylo
                     11:  *
                     12:  * Rhosts or /etc/hosts.equiv authentication combined with RSA host
                     13:  * authentication.
                     14:  *
                     15:  */
1.1       provos     16:
                     17: #include "includes.h"
1.12    ! markus     18: RCSID("$Id: auth-rh-rsa.c,v 1.11 2000/03/23 22:15:33 markus Exp $");
1.1       provos     19:
                     20: #include "packet.h"
                     21: #include "ssh.h"
                     22: #include "xmalloc.h"
                     23: #include "uidswap.h"
1.4       markus     24: #include "servconf.h"
1.1       provos     25:
1.12    ! markus     26: #include <openssl/rsa.h>
        !            27: #include <openssl/dsa.h>
1.11      markus     28: #include "key.h"
                     29: #include "hostfile.h"
                     30:
1.10      markus     31: /*
                     32:  * Tries to authenticate the user using the .rhosts file and the host using
                     33:  * its host key.  Returns true if authentication succeeds.
                     34:  */
1.1       provos     35:
1.8       markus     36: int
1.11      markus     37: auth_rhosts_rsa(struct passwd *pw, const char *client_user, RSA *client_host_key)
1.1       provos     38: {
1.8       markus     39:        extern ServerOptions options;
                     40:        const char *canonical_hostname;
                     41:        HostStatus host_status;
1.11      markus     42:        Key *client_key, *found;
1.8       markus     43:
                     44:        debug("Trying rhosts with RSA host authentication for %.100s", client_user);
                     45:
1.11      markus     46:        if (client_host_key == NULL)
                     47:                return 0;
                     48:
1.8       markus     49:        /* Check if we would accept it using rhosts authentication. */
                     50:        if (!auth_rhosts(pw, client_user))
                     51:                return 0;
                     52:
                     53:        canonical_hostname = get_canonical_hostname();
                     54:
1.11      markus     55:        debug("Rhosts RSA authentication: canonical host %.900s", canonical_hostname);
                     56:
                     57:        /* wrap the RSA key into a 'generic' key */
                     58:        client_key = key_new(KEY_RSA);
                     59:        BN_copy(client_key->rsa->e, client_host_key->e);
                     60:        BN_copy(client_key->rsa->n, client_host_key->n);
                     61:        found = key_new(KEY_RSA);
1.8       markus     62:
                     63:        /* Check if we know the host and its host key. */
                     64:        host_status = check_host_in_hostfile(SSH_SYSTEM_HOSTFILE, canonical_hostname,
1.11      markus     65:            client_key, found);
1.8       markus     66:
                     67:        /* Check user host file unless ignored. */
                     68:        if (host_status != HOST_OK && !options.ignore_user_known_hosts) {
                     69:                struct stat st;
                     70:                char *user_hostfile = tilde_expand_filename(SSH_USER_HOSTFILE, pw->pw_uid);
1.10      markus     71:                /*
                     72:                 * Check file permissions of SSH_USER_HOSTFILE, auth_rsa()
                     73:                 * did already check pw->pw_dir, but there is a race XXX
                     74:                 */
1.8       markus     75:                if (options.strict_modes &&
                     76:                    (stat(user_hostfile, &st) == 0) &&
                     77:                    ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
                     78:                     (st.st_mode & 022) != 0)) {
                     79:                        log("Rhosts RSA authentication refused for %.100s: bad owner or modes for %.200s",
                     80:                            pw->pw_name, user_hostfile);
                     81:                } else {
                     82:                        /* XXX race between stat and the following open() */
                     83:                        temporarily_use_uid(pw->pw_uid);
                     84:                        host_status = check_host_in_hostfile(user_hostfile, canonical_hostname,
1.11      markus     85:                            client_key, found);
1.8       markus     86:                        restore_uid();
                     87:                }
                     88:                xfree(user_hostfile);
                     89:        }
1.11      markus     90:        key_free(client_key);
                     91:        key_free(found);
1.8       markus     92:
                     93:        if (host_status != HOST_OK) {
                     94:                debug("Rhosts with RSA host authentication denied: unknown or invalid host key");
                     95:                packet_send_debug("Your host key cannot be verified: unknown or invalid host key.");
                     96:                return 0;
                     97:        }
                     98:        /* A matching host key was found and is known. */
                     99:
                    100:        /* Perform the challenge-response dialog with the client for the host key. */
1.11      markus    101:        if (!auth_rsa_challenge_dialog(client_host_key)) {
1.8       markus    102:                log("Client on %.800s failed to respond correctly to host authentication.",
                    103:                    canonical_hostname);
                    104:                return 0;
                    105:        }
1.10      markus    106:        /*
                    107:         * We have authenticated the user using .rhosts or /etc/hosts.equiv,
                    108:         * and the host using RSA. We accept the authentication.
                    109:         */
1.8       markus    110:
                    111:        verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.",
1.11      markus    112:           pw->pw_name, client_user, canonical_hostname);
1.8       markus    113:        packet_send_debug("Rhosts with RSA host authentication accepted.");
                    114:        return 1;
1.1       provos    115: }