Annotation of src/usr.bin/ssh/auth-rh-rsa.c, Revision 1.18
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"
1.18 ! markus 16: RCSID("$OpenBSD: auth-rh-rsa.c,v 1.17 2000/10/03 18:03:03 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"
28:
1.10 markus 29: /*
30: * Tries to authenticate the user using the .rhosts file and the host using
31: * its host key. Returns true if authentication succeeds.
32: */
1.1 provos 33:
1.13 markus 34: int
1.11 markus 35: auth_rhosts_rsa(struct passwd *pw, const char *client_user, RSA *client_host_key)
1.1 provos 36: {
1.8 markus 37: extern ServerOptions options;
38: const char *canonical_hostname;
39: HostStatus host_status;
1.11 markus 40: Key *client_key, *found;
1.8 markus 41:
1.17 markus 42: debug("Trying rhosts with RSA host authentication for client user %.100s", client_user);
1.8 markus 43:
1.17 markus 44: if (pw == NULL || client_host_key == NULL)
1.11 markus 45: return 0;
46:
1.8 markus 47: /* Check if we would accept it using rhosts authentication. */
48: if (!auth_rhosts(pw, client_user))
49: return 0;
50:
51: canonical_hostname = get_canonical_hostname();
52:
1.11 markus 53: debug("Rhosts RSA authentication: canonical host %.900s", canonical_hostname);
54:
55: /* wrap the RSA key into a 'generic' key */
1.18 ! markus 56: client_key = key_new(KEY_RSA1);
1.11 markus 57: BN_copy(client_key->rsa->e, client_host_key->e);
58: BN_copy(client_key->rsa->n, client_host_key->n);
1.18 ! markus 59: found = key_new(KEY_RSA1);
1.8 markus 60:
61: /* Check if we know the host and its host key. */
62: host_status = check_host_in_hostfile(SSH_SYSTEM_HOSTFILE, canonical_hostname,
1.11 markus 63: client_key, found);
1.8 markus 64:
65: /* Check user host file unless ignored. */
66: if (host_status != HOST_OK && !options.ignore_user_known_hosts) {
67: struct stat st;
68: char *user_hostfile = tilde_expand_filename(SSH_USER_HOSTFILE, pw->pw_uid);
1.10 markus 69: /*
70: * Check file permissions of SSH_USER_HOSTFILE, auth_rsa()
71: * did already check pw->pw_dir, but there is a race XXX
72: */
1.8 markus 73: if (options.strict_modes &&
74: (stat(user_hostfile, &st) == 0) &&
75: ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
76: (st.st_mode & 022) != 0)) {
77: log("Rhosts RSA authentication refused for %.100s: bad owner or modes for %.200s",
78: pw->pw_name, user_hostfile);
79: } else {
80: /* XXX race between stat and the following open() */
81: temporarily_use_uid(pw->pw_uid);
82: host_status = check_host_in_hostfile(user_hostfile, canonical_hostname,
1.11 markus 83: client_key, found);
1.8 markus 84: restore_uid();
85: }
86: xfree(user_hostfile);
87: }
1.11 markus 88: key_free(client_key);
89: key_free(found);
1.8 markus 90:
91: if (host_status != HOST_OK) {
92: debug("Rhosts with RSA host authentication denied: unknown or invalid host key");
93: packet_send_debug("Your host key cannot be verified: unknown or invalid host key.");
94: return 0;
95: }
96: /* A matching host key was found and is known. */
97:
98: /* Perform the challenge-response dialog with the client for the host key. */
1.11 markus 99: if (!auth_rsa_challenge_dialog(client_host_key)) {
1.8 markus 100: log("Client on %.800s failed to respond correctly to host authentication.",
101: canonical_hostname);
102: return 0;
103: }
1.10 markus 104: /*
105: * We have authenticated the user using .rhosts or /etc/hosts.equiv,
106: * and the host using RSA. We accept the authentication.
107: */
1.8 markus 108:
109: verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.",
1.11 markus 110: pw->pw_name, client_user, canonical_hostname);
1.8 markus 111: packet_send_debug("Rhosts with RSA host authentication accepted.");
112: return 1;
1.1 provos 113: }