Annotation of src/usr.bin/ssh/auth-rh-rsa.c, Revision 1.22
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"
1.22 ! markus 16: RCSID("$OpenBSD: auth-rh-rsa.c,v 1.21 2001/01/21 19:05:42 markus Exp $");
1.1 provos 17:
18: #include "packet.h"
19: #include "xmalloc.h"
20: #include "uidswap.h"
1.21 markus 21: #include "log.h"
1.4 markus 22: #include "servconf.h"
1.11 markus 23: #include "key.h"
24: #include "hostfile.h"
1.20 markus 25: #include "pathnames.h"
1.21 markus 26: #include "auth.h"
27: #include "tildexpand.h"
28: #include "canohost.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:
1.22 ! markus 52: canonical_hostname = get_canonical_hostname(
! 53: options.reverse_mapping_check);
1.8 markus 54:
1.11 markus 55: debug("Rhosts RSA authentication: canonical host %.900s", canonical_hostname);
56:
57: /* wrap the RSA key into a 'generic' key */
1.18 markus 58: client_key = key_new(KEY_RSA1);
1.11 markus 59: BN_copy(client_key->rsa->e, client_host_key->e);
60: BN_copy(client_key->rsa->n, client_host_key->n);
1.18 markus 61: found = key_new(KEY_RSA1);
1.8 markus 62:
63: /* Check if we know the host and its host key. */
1.20 markus 64: host_status = check_host_in_hostfile(_PATH_SSH_SYSTEM_HOSTFILE, canonical_hostname,
1.19 markus 65: client_key, found, NULL);
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;
1.20 markus 70: char *user_hostfile = tilde_expand_filename(_PATH_SSH_USER_HOSTFILE, pw->pw_uid);
1.10 markus 71: /*
1.20 markus 72: * Check file permissions of _PATH_SSH_USER_HOSTFILE, auth_rsa()
1.10 markus 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,
1.19 markus 85: client_key, found, NULL);
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: }
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