| 1 | /* |
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| 2 | * Author: Tatu Ylonen <ylo@cs.hut.fi> |
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| 3 | * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland |
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| 4 | * All rights reserved |
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| 5 | * Rhosts or /etc/hosts.equiv authentication combined with RSA host |
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| 6 | * authentication. |
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| 7 | * |
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| 8 | * As far as I am concerned, the code I have written for this software |
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| 9 | * can be used freely for any purpose. Any derived versions of this |
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| 10 | * software must be clearly marked as such, and if the derived work is |
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| 11 | * incompatible with the protocol description in the RFC file, it must be |
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| 12 | * called by a name other than "ssh" or "Secure Shell". |
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| 13 | */ |
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| 14 | |
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| 15 | #include "includes.h" |
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| 16 | RCSID("$OpenBSD: auth-rh-rsa.c,v 1.34 2002/03/25 09:25:06 markus Exp $"); |
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| 17 | |
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| 18 | #include "packet.h" |
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| 19 | #include "uidswap.h" |
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| 20 | #include "log.h" |
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| 21 | #include "servconf.h" |
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| 22 | #include "key.h" |
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| 23 | #include "hostfile.h" |
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| 24 | #include "pathnames.h" |
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| 25 | #include "auth.h" |
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| 26 | #include "canohost.h" |
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| 27 | |
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| 28 | #include "monitor_wrap.h" |
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| 29 | |
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| 30 | /* import */ |
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| 31 | extern ServerOptions options; |
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| 32 | |
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| 33 | int |
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| 34 | auth_rhosts_rsa_key_allowed(struct passwd *pw, char *cuser, char *chost, |
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| 35 | Key *client_host_key) |
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| 36 | { |
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| 37 | HostStatus host_status; |
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| 38 | |
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| 39 | /* Check if we would accept it using rhosts authentication. */ |
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| 40 | if (!auth_rhosts(pw, cuser)) |
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| 41 | return 0; |
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| 42 | |
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| 43 | host_status = check_key_in_hostfiles(pw, client_host_key, |
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| 44 | chost, _PATH_SSH_SYSTEM_HOSTFILE, |
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| 45 | options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE); |
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| 46 | |
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| 47 | return (host_status == HOST_OK); |
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| 48 | } |
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| 49 | |
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| 50 | /* |
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| 51 | * Tries to authenticate the user using the .rhosts file and the host using |
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| 52 | * its host key. Returns true if authentication succeeds. |
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| 53 | */ |
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| 54 | int |
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| 55 | auth_rhosts_rsa(struct passwd *pw, char *cuser, Key *client_host_key) |
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| 56 | { |
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| 57 | char *chost; |
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| 58 | |
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| 59 | debug("Trying rhosts with RSA host authentication for client user %.100s", |
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| 60 | cuser); |
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| 61 | |
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| 62 | if (pw == NULL || client_host_key == NULL || |
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| 63 | client_host_key->rsa == NULL) |
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| 64 | return 0; |
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| 65 | |
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| 66 | chost = (char *)get_canonical_hostname(options.verify_reverse_mapping); |
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| 67 | debug("Rhosts RSA authentication: canonical host %.900s", chost); |
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| 68 | |
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| 69 | if (!PRIVSEP(auth_rhosts_rsa_key_allowed(pw, cuser, chost, client_host_key))) { |
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| 70 | debug("Rhosts with RSA host authentication denied: unknown or invalid host key"); |
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| 71 | packet_send_debug("Your host key cannot be verified: unknown or invalid host key."); |
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| 72 | return 0; |
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| 73 | } |
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| 74 | /* A matching host key was found and is known. */ |
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| 75 | |
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| 76 | /* Perform the challenge-response dialog with the client for the host key. */ |
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| 77 | if (!auth_rsa_challenge_dialog(client_host_key)) { |
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| 78 | log("Client on %.800s failed to respond correctly to host authentication.", |
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| 79 | chost); |
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| 80 | return 0; |
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| 81 | } |
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| 82 | /* |
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| 83 | * We have authenticated the user using .rhosts or /etc/hosts.equiv, |
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| 84 | * and the host using RSA. We accept the authentication. |
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| 85 | */ |
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| 86 | |
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| 87 | verbose("Rhosts with RSA host authentication accepted for %.100s, %.100s on %.700s.", |
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| 88 | pw->pw_name, cuser, chost); |
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| 89 | packet_send_debug("Rhosts with RSA host authentication accepted."); |
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| 90 | return 1; |
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| 91 | } |
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