Annotation of src/usr.bin/ssh/auth-rh-rsa.c, Revision 1.9
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"
1.9 ! deraadt 18: RCSID("$Id: auth-rh-rsa.c,v 1.8 1999/11/23 22:25:52 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: }