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Annotation of src/usr.bin/ssh/auth-rh-rsa.c, Revision 1.8

1.1       provos      1: /*
                      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: */
                     16:
                     17: #include "includes.h"
1.8     ! markus     18: RCSID("$Id: auth-rh-rsa.c,v 1.7 1999/11/22 21:02:38 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:
                     26: /* Tries to authenticate the user using the .rhosts file and the host using
1.4       markus     27:    its host key.  Returns true if authentication succeeds. */
1.1       provos     28:
1.8     ! markus     29: int
        !            30: auth_rhosts_rsa(struct passwd *pw, const char *client_user,
        !            31:                BIGNUM *client_host_key_e, BIGNUM *client_host_key_n)
1.1       provos     32: {
1.8     ! markus     33:        extern ServerOptions options;
        !            34:        const char *canonical_hostname;
        !            35:        HostStatus host_status;
        !            36:        BIGNUM *ke, *kn;
        !            37:
        !            38:        debug("Trying rhosts with RSA host authentication for %.100s", client_user);
        !            39:
        !            40:        /* Check if we would accept it using rhosts authentication. */
        !            41:        if (!auth_rhosts(pw, client_user))
        !            42:                return 0;
        !            43:
        !            44:        canonical_hostname = get_canonical_hostname();
        !            45:
        !            46:        debug("Rhosts RSA authentication: canonical host %.900s",
        !            47:              canonical_hostname);
        !            48:
        !            49:        /* Check if we know the host and its host key. */
        !            50:        ke = BN_new();
        !            51:        kn = BN_new();
        !            52:        host_status = check_host_in_hostfile(SSH_SYSTEM_HOSTFILE, canonical_hostname,
        !            53:                                             client_host_key_e, client_host_key_n,
        !            54:                                             ke, kn);
        !            55:
        !            56:        /* Check user host file unless ignored. */
        !            57:        if (host_status != HOST_OK && !options.ignore_user_known_hosts) {
        !            58:                struct stat st;
        !            59:                char *user_hostfile = tilde_expand_filename(SSH_USER_HOSTFILE, pw->pw_uid);
        !            60:                /* Check file permissions of SSH_USER_HOSTFILE, auth_rsa()
        !            61:                   did already check pw->pw_dir, but there is a race XXX */
        !            62:                if (options.strict_modes &&
        !            63:                    (stat(user_hostfile, &st) == 0) &&
        !            64:                    ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
        !            65:                     (st.st_mode & 022) != 0)) {
        !            66:                        log("Rhosts RSA authentication refused for %.100s: bad owner or modes for %.200s",
        !            67:                            pw->pw_name, user_hostfile);
        !            68:                } else {
        !            69:                        /* XXX race between stat and the following open() */
        !            70:                        temporarily_use_uid(pw->pw_uid);
        !            71:                        host_status = check_host_in_hostfile(user_hostfile, canonical_hostname,
        !            72:                                                             client_host_key_e, client_host_key_n,
        !            73:                                                             ke, kn);
        !            74:                        restore_uid();
        !            75:                }
        !            76:                xfree(user_hostfile);
        !            77:        }
        !            78:        BN_free(ke);
        !            79:        BN_free(kn);
        !            80:
        !            81:        if (host_status != HOST_OK) {
        !            82:                debug("Rhosts with RSA host authentication denied: unknown or invalid host key");
        !            83:                packet_send_debug("Your host key cannot be verified: unknown or invalid host key.");
        !            84:                return 0;
        !            85:        }
        !            86:        /* A matching host key was found and is known. */
        !            87:
        !            88:        /* Perform the challenge-response dialog with the client for the host key. */
        !            89:        if (!auth_rsa_challenge_dialog(client_host_key_e, client_host_key_n)) {
        !            90:                log("Client on %.800s failed to respond correctly to host authentication.",
        !            91:                    canonical_hostname);
        !            92:                return 0;
        !            93:        }
        !            94:        /* We have authenticated the user using .rhosts or /etc/hosts.equiv, and the host using RSA.
        !            95:           We accept the authentication. */
        !            96:
        !            97:        verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.",
        !            98:                pw->pw_name, client_user, canonical_hostname);
        !            99:        packet_send_debug("Rhosts with RSA host authentication accepted.");
        !           100:        return 1;
1.1       provos    101: }