Annotation of src/usr.bin/ssh/auth-rh-rsa.c, Revision 1.7
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"
1.7 ! markus 18: RCSID("$Id: auth-rh-rsa.c,v 1.6 1999/11/15 20:53:24 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:
29: int auth_rhosts_rsa(struct passwd *pw, const char *client_user,
1.4 markus 30: BIGNUM *client_host_key_e, BIGNUM *client_host_key_n)
1.1 provos 31: {
1.4 markus 32: extern ServerOptions options;
1.1 provos 33: const char *canonical_hostname;
1.2 provos 34: HostStatus host_status;
35: BIGNUM *ke, *kn;
1.1 provos 36:
37: debug("Trying rhosts with RSA host authentication for %.100s", client_user);
38:
39: /* Check if we would accept it using rhosts authentication. */
1.5 markus 40: if (!auth_rhosts(pw, client_user))
1.1 provos 41: return 0;
42:
43: canonical_hostname = get_canonical_hostname();
44:
45: debug("Rhosts RSA authentication: canonical host %.900s",
46: canonical_hostname);
47:
48: /* Check if we know the host and its host key. */
49: /* Check system-wide host file. */
1.2 provos 50: ke = BN_new();
51: kn = BN_new();
52: host_status = check_host_in_hostfile(SSH_SYSTEM_HOSTFILE, canonical_hostname,
1.6 markus 53: client_host_key_e, client_host_key_n, ke, kn);
1.4 markus 54:
55: /* Check user host file unless ignored. */
56: if (host_status != HOST_OK && !options.ignore_user_known_hosts) {
1.3 markus 57: struct stat st;
58: char *user_hostfile = tilde_expand_filename(SSH_USER_HOSTFILE, pw->pw_uid);
59: /* Check file permissions of SSH_USER_HOSTFILE,
60: auth_rsa() did already check pw->pw_dir, but there is a race XXX */
1.4 markus 61: if (options.strict_modes &&
1.3 markus 62: (stat(user_hostfile, &st) == 0) &&
63: ((st.st_uid != 0 && st.st_uid != pw->pw_uid) ||
64: (st.st_mode & 022) != 0)) {
65: log("Rhosts RSA authentication refused for %.100s: bad owner or modes for %.200s",
66: pw->pw_name, user_hostfile);
67: } else {
68: /* XXX race between stat and the following open() */
69: temporarily_use_uid(pw->pw_uid);
70: host_status = check_host_in_hostfile(user_hostfile, canonical_hostname,
1.6 markus 71: client_host_key_e, client_host_key_n, ke, kn);
1.3 markus 72: restore_uid();
73: }
74: xfree(user_hostfile);
75: }
1.2 provos 76: BN_free(ke);
77: BN_free(kn);
1.3 markus 78:
1.2 provos 79: if (host_status != HOST_OK) {
80: /* The host key was not found. */
81: debug("Rhosts with RSA host authentication denied: unknown or invalid host key");
82: packet_send_debug("Your host key cannot be verified: unknown or invalid host key.");
83: return 0;
84: }
85:
1.1 provos 86: /* A matching host key was found and is known. */
87:
88: /* Perform the challenge-response dialog with the client for the host key. */
1.6 markus 89: if (!auth_rsa_challenge_dialog(client_host_key_e, client_host_key_n))
1.1 provos 90: {
91: log("Client on %.800s failed to respond correctly to host authentication.",
92: canonical_hostname);
93: return 0;
94: }
95:
96: /* We have authenticated the user using .rhosts or /etc/hosts.equiv, and
97: the host using RSA. We accept the authentication. */
98:
1.7 ! markus 99: verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.",
1.1 provos 100: pw->pw_name, client_user, canonical_hostname);
101: packet_send_debug("Rhosts with RSA host authentication accepted.");
102: return 1;
103: }