Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 1 | /* |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
| 4 | * All rights reserved |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 5 | * Rhosts or /etc/hosts.equiv authentication combined with RSA host |
| 6 | * authentication. |
| 7 | * |
Damien Miller | e4340be | 2000-09-16 13:29:08 +1100 | [diff] [blame] | 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". |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 13 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 14 | |
| 15 | #include "includes.h" |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 16 | RCSID("$OpenBSD: auth-rh-rsa.c,v 1.17 2000/10/03 18:03:03 markus Exp $"); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 17 | |
| 18 | #include "packet.h" |
| 19 | #include "ssh.h" |
| 20 | #include "xmalloc.h" |
| 21 | #include "uidswap.h" |
Damien Miller | 3226509 | 1999-11-12 11:33:04 +1100 | [diff] [blame] | 22 | #include "servconf.h" |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 23 | |
Damien Miller | 5f05637 | 2000-04-16 12:31:48 +1000 | [diff] [blame] | 24 | #include <openssl/rsa.h> |
| 25 | #include <openssl/dsa.h> |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 26 | #include "key.h" |
| 27 | #include "hostfile.h" |
| 28 | |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 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 | */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 33 | |
Damien Miller | 4af5130 | 2000-04-16 11:18:38 +1000 | [diff] [blame] | 34 | int |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 35 | auth_rhosts_rsa(struct passwd *pw, const char *client_user, RSA *client_host_key) |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 36 | { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 37 | extern ServerOptions options; |
| 38 | const char *canonical_hostname; |
| 39 | HostStatus host_status; |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 40 | Key *client_key, *found; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 41 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 42 | debug("Trying rhosts with RSA host authentication for client user %.100s", client_user); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 43 | |
Damien Miller | 874d77b | 2000-10-14 16:23:11 +1100 | [diff] [blame] | 44 | if (pw == NULL || client_host_key == NULL) |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 45 | return 0; |
| 46 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 47 | /* Check if we would accept it using rhosts authentication. */ |
| 48 | if (!auth_rhosts(pw, client_user)) |
| 49 | return 0; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 50 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 51 | canonical_hostname = get_canonical_hostname(); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 52 | |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 53 | debug("Rhosts RSA authentication: canonical host %.900s", canonical_hostname); |
| 54 | |
| 55 | /* wrap the RSA key into a 'generic' key */ |
| 56 | client_key = key_new(KEY_RSA); |
| 57 | BN_copy(client_key->rsa->e, client_host_key->e); |
| 58 | BN_copy(client_key->rsa->n, client_host_key->n); |
| 59 | found = key_new(KEY_RSA); |
Damien Miller | 3226509 | 1999-11-12 11:33:04 +1100 | [diff] [blame] | 60 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 61 | /* Check if we know the host and its host key. */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 62 | host_status = check_host_in_hostfile(SSH_SYSTEM_HOSTFILE, canonical_hostname, |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 63 | client_key, found); |
Damien Miller | 33e511e | 1999-11-11 11:43:13 +1100 | [diff] [blame] | 64 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 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); |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 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 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 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, |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 83 | client_key, found); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 84 | restore_uid(); |
| 85 | } |
| 86 | xfree(user_hostfile); |
| 87 | } |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 88 | key_free(client_key); |
| 89 | key_free(found); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 90 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 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. */ |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 97 | |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 98 | /* Perform the challenge-response dialog with the client for the host key. */ |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 99 | if (!auth_rsa_challenge_dialog(client_host_key)) { |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 100 | log("Client on %.800s failed to respond correctly to host authentication.", |
| 101 | canonical_hostname); |
| 102 | return 0; |
| 103 | } |
Damien Miller | 5428f64 | 1999-11-25 11:54:57 +1100 | [diff] [blame] | 104 | /* |
| 105 | * We have authenticated the user using .rhosts or /etc/hosts.equiv, |
| 106 | * and the host using RSA. We accept the authentication. |
| 107 | */ |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 108 | |
| 109 | verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.", |
Damien Miller | 450a7a1 | 2000-03-26 13:04:51 +1000 | [diff] [blame] | 110 | pw->pw_name, client_user, canonical_hostname); |
Damien Miller | 95def09 | 1999-11-25 00:26:21 +1100 | [diff] [blame] | 111 | packet_send_debug("Rhosts with RSA host authentication accepted."); |
| 112 | return 1; |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 113 | } |