Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 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" |
Damien Miller | 33e511e | 1999-11-11 11:43:13 +1100 | [diff] [blame] | 18 | RCSID("$Id: auth-rh-rsa.c,v 1.2 1999/11/11 00:43:13 damien Exp $"); |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 19 | |
| 20 | #include "packet.h" |
| 21 | #include "ssh.h" |
| 22 | #include "xmalloc.h" |
| 23 | #include "uidswap.h" |
| 24 | |
| 25 | /* Tries to authenticate the user using the .rhosts file and the host using |
| 26 | its host key. Returns true if authentication succeeds. |
| 27 | .rhosts and .shosts will be ignored if ignore_rhosts is non-zero. */ |
| 28 | |
| 29 | int auth_rhosts_rsa(struct passwd *pw, const char *client_user, |
| 30 | unsigned int client_host_key_bits, |
| 31 | BIGNUM *client_host_key_e, BIGNUM *client_host_key_n, |
| 32 | int ignore_rhosts, int strict_modes) |
| 33 | { |
| 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, ignore_rhosts, strict_modes)) |
| 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 | /* Check system-wide host file. */ |
| 51 | ke = BN_new(); |
| 52 | kn = BN_new(); |
| 53 | host_status = check_host_in_hostfile(SSH_SYSTEM_HOSTFILE, canonical_hostname, |
| 54 | client_host_key_bits, client_host_key_e, |
| 55 | client_host_key_n, ke, kn); |
Damien Miller | 33e511e | 1999-11-11 11:43:13 +1100 | [diff] [blame] | 56 | /* Check user host file. */ |
| 57 | if (host_status != HOST_OK) { |
| 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, |
| 61 | auth_rsa() did already check pw->pw_dir, but there is a race XXX */ |
| 62 | if (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_bits, client_host_key_e, |
| 73 | client_host_key_n, ke, kn); |
| 74 | restore_uid(); |
| 75 | } |
| 76 | xfree(user_hostfile); |
| 77 | } |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 78 | BN_free(ke); |
| 79 | BN_free(kn); |
Damien Miller | 33e511e | 1999-11-11 11:43:13 +1100 | [diff] [blame] | 80 | |
Damien Miller | d4a8b7e | 1999-10-27 13:42:43 +1000 | [diff] [blame] | 81 | if (host_status != HOST_OK) { |
| 82 | /* The host key was not found. */ |
| 83 | debug("Rhosts with RSA host authentication denied: unknown or invalid host key"); |
| 84 | packet_send_debug("Your host key cannot be verified: unknown or invalid host key."); |
| 85 | return 0; |
| 86 | } |
| 87 | |
| 88 | /* A matching host key was found and is known. */ |
| 89 | |
| 90 | /* Perform the challenge-response dialog with the client for the host key. */ |
| 91 | if (!auth_rsa_challenge_dialog(client_host_key_bits, |
| 92 | client_host_key_e, client_host_key_n)) |
| 93 | { |
| 94 | log("Client on %.800s failed to respond correctly to host authentication.", |
| 95 | canonical_hostname); |
| 96 | return 0; |
| 97 | } |
| 98 | |
| 99 | /* We have authenticated the user using .rhosts or /etc/hosts.equiv, and |
| 100 | the host using RSA. We accept the authentication. */ |
| 101 | |
| 102 | log("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.", |
| 103 | pw->pw_name, client_user, canonical_hostname); |
| 104 | packet_send_debug("Rhosts with RSA host authentication accepted."); |
| 105 | return 1; |
| 106 | } |