Annotation of src/usr.bin/ssh/auth-rh-rsa.c, Revision 1.20
1.1 provos 1: /*
1.9 deraadt 2: * Author: Tatu Ylonen <ylo@cs.hut.fi>
3: * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
4: * All rights reserved
5: * Rhosts or /etc/hosts.equiv authentication combined with RSA host
6: * authentication.
7: *
1.15 deraadt 8: * As far as I am concerned, the code I have written for this software
9: * can be used freely for any purpose. Any derived versions of this
10: * software must be clearly marked as such, and if the derived work is
11: * incompatible with the protocol description in the RFC file, it must be
12: * called by a name other than "ssh" or "Secure Shell".
1.9 deraadt 13: */
1.1 provos 14:
15: #include "includes.h"
1.20 ! markus 16: RCSID("$OpenBSD: auth-rh-rsa.c,v 1.19 2000/12/21 15:10:16 markus Exp $");
1.1 provos 17:
18: #include "packet.h"
19: #include "ssh.h"
20: #include "xmalloc.h"
21: #include "uidswap.h"
1.4 markus 22: #include "servconf.h"
1.1 provos 23:
1.12 markus 24: #include <openssl/rsa.h>
25: #include <openssl/dsa.h>
1.11 markus 26: #include "key.h"
27: #include "hostfile.h"
1.20 ! markus 28: #include "pathnames.h"
1.11 markus 29:
1.10 markus 30: /*
31: * Tries to authenticate the user using the .rhosts file and the host using
32: * its host key. Returns true if authentication succeeds.
33: */
1.1 provos 34:
1.13 markus 35: int
1.11 markus 36: auth_rhosts_rsa(struct passwd *pw, const char *client_user, RSA *client_host_key)
1.1 provos 37: {
1.8 markus 38: extern ServerOptions options;
39: const char *canonical_hostname;
40: HostStatus host_status;
1.11 markus 41: Key *client_key, *found;
1.8 markus 42:
1.17 markus 43: debug("Trying rhosts with RSA host authentication for client user %.100s", client_user);
1.8 markus 44:
1.17 markus 45: if (pw == NULL || client_host_key == NULL)
1.11 markus 46: return 0;
47:
1.8 markus 48: /* Check if we would accept it using rhosts authentication. */
49: if (!auth_rhosts(pw, client_user))
50: return 0;
51:
52: canonical_hostname = get_canonical_hostname();
53:
1.11 markus 54: debug("Rhosts RSA authentication: canonical host %.900s", canonical_hostname);
55:
56: /* wrap the RSA key into a 'generic' key */
1.18 markus 57: client_key = key_new(KEY_RSA1);
1.11 markus 58: BN_copy(client_key->rsa->e, client_host_key->e);
59: BN_copy(client_key->rsa->n, client_host_key->n);
1.18 markus 60: found = key_new(KEY_RSA1);
1.8 markus 61:
62: /* Check if we know the host and its host key. */
1.20 ! markus 63: host_status = check_host_in_hostfile(_PATH_SSH_SYSTEM_HOSTFILE, canonical_hostname,
1.19 markus 64: client_key, found, NULL);
1.8 markus 65:
66: /* Check user host file unless ignored. */
67: if (host_status != HOST_OK && !options.ignore_user_known_hosts) {
68: struct stat st;
1.20 ! markus 69: char *user_hostfile = tilde_expand_filename(_PATH_SSH_USER_HOSTFILE, pw->pw_uid);
1.10 markus 70: /*
1.20 ! markus 71: * Check file permissions of _PATH_SSH_USER_HOSTFILE, auth_rsa()
1.10 markus 72: * did already check pw->pw_dir, but there is a race XXX
73: */
1.8 markus 74: if (options.strict_modes &&
75: (stat(user_hostfile, &st) == 0) &&
76: ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
77: (st.st_mode & 022) != 0)) {
78: log("Rhosts RSA authentication refused for %.100s: bad owner or modes for %.200s",
79: pw->pw_name, user_hostfile);
80: } else {
81: /* XXX race between stat and the following open() */
82: temporarily_use_uid(pw->pw_uid);
83: host_status = check_host_in_hostfile(user_hostfile, canonical_hostname,
1.19 markus 84: client_key, found, NULL);
1.8 markus 85: restore_uid();
86: }
87: xfree(user_hostfile);
88: }
1.11 markus 89: key_free(client_key);
90: key_free(found);
1.8 markus 91:
92: if (host_status != HOST_OK) {
93: debug("Rhosts with RSA host authentication denied: unknown or invalid host key");
94: packet_send_debug("Your host key cannot be verified: unknown or invalid host key.");
95: return 0;
96: }
97: /* A matching host key was found and is known. */
98:
99: /* Perform the challenge-response dialog with the client for the host key. */
1.11 markus 100: if (!auth_rsa_challenge_dialog(client_host_key)) {
1.8 markus 101: log("Client on %.800s failed to respond correctly to host authentication.",
102: canonical_hostname);
103: return 0;
104: }
1.10 markus 105: /*
106: * We have authenticated the user using .rhosts or /etc/hosts.equiv,
107: * and the host using RSA. We accept the authentication.
108: */
1.8 markus 109:
110: verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.",
1.11 markus 111: pw->pw_name, client_user, canonical_hostname);
1.8 markus 112: packet_send_debug("Rhosts with RSA host authentication accepted.");
113: return 1;
1.1 provos 114: }