Main Page | Namespace List | Class List | Directories | File List | Class Members | File Members

auth2-hostbased.c File Reference

#include "includes.h"
#include "ssh2.h"
#include "xmalloc.h"
#include "packet.h"
#include "buffer.h"
#include "log.h"
#include "servconf.h"
#include "compat.h"
#include "bufaux.h"
#include "auth.h"
#include "key.h"
#include "canohost.h"
#include "monitor_wrap.h"
#include "pathnames.h"

Go to the source code of this file.

Functions

 RCSID ("$OpenBSD: auth2-hostbased.c,v 1.6 2004/01/19 21:25:15 markus Exp $")
static int userauth_hostbased (Authctxt *authctxt)
int hostbased_key_allowed (struct passwd *pw, const char *cuser, char *chost, Key *key)

Variables

ServerOptions options
u_charsession_id2
u_int session_id2_len
Authmethod method_hostbased


Function Documentation

int hostbased_key_allowed struct passwd *  pw,
const char cuser,
char chost,
Key key
 

Definition at line 132 of file auth2-hostbased.c.

References _PATH_SSH_SYSTEM_HOSTFILE, _PATH_SSH_SYSTEM_HOSTFILE2, _PATH_SSH_USER_HOSTFILE, _PATH_SSH_USER_HOSTFILE2, auth_rhosts2(), check_key_in_hostfiles(), debug2(), get_canonical_hostname(), get_remote_ipaddr(), HOST_NEW, HOST_OK, ServerOptions::hostbased_uses_name_from_packet_only, ServerOptions::ignore_user_known_hosts, logit(), and ServerOptions::use_dns.

Referenced by mm_answer_keyallowed(), and userauth_hostbased().

00134 {
00135         const char *resolvedname, *ipaddr, *lookup;
00136         HostStatus host_status;
00137         int len;
00138 
00139         resolvedname = get_canonical_hostname(options.use_dns);
00140         ipaddr = get_remote_ipaddr();
00141 
00142         debug2("userauth_hostbased: chost %s resolvedname %s ipaddr %s",
00143             chost, resolvedname, ipaddr);
00144 
00145         if (options.hostbased_uses_name_from_packet_only) {
00146                 if (auth_rhosts2(pw, cuser, chost, chost) == 0)
00147                         return 0;
00148                 lookup = chost;
00149         } else {
00150                 if (((len = strlen(chost)) > 0) && chost[len - 1] == '.') {
00151                         debug2("stripping trailing dot from chost %s", chost);
00152                         chost[len - 1] = '\0';
00153                 }
00154                 if (strcasecmp(resolvedname, chost) != 0)
00155                         logit("userauth_hostbased mismatch: "
00156                             "client sends %s, but we resolve %s to %s",
00157                             chost, ipaddr, resolvedname);
00158                 if (auth_rhosts2(pw, cuser, resolvedname, ipaddr) == 0)
00159                         return 0;
00160                 lookup = resolvedname;
00161         }
00162         debug2("userauth_hostbased: access allowed by auth_rhosts2");
00163 
00164         host_status = check_key_in_hostfiles(pw, key, lookup,
00165             _PATH_SSH_SYSTEM_HOSTFILE,
00166             options.ignore_user_known_hosts ? NULL : _PATH_SSH_USER_HOSTFILE);
00167 
00168         /* backward compat if no key has been found. */
00169         if (host_status == HOST_NEW)
00170                 host_status = check_key_in_hostfiles(pw, key, lookup,
00171                     _PATH_SSH_SYSTEM_HOSTFILE2,
00172                     options.ignore_user_known_hosts ? NULL :
00173                     _PATH_SSH_USER_HOSTFILE2);
00174 
00175         return (host_status == HOST_OK);
00176 }

RCSID "$OpenBSD: auth2-hostbased.  c,
v 1.6 2004/01/19 21:25:15 markus Exp $" 
 

static int userauth_hostbased Authctxt authctxt  )  [static]
 

Definition at line 48 of file auth2-hostbased.c.

References buffer_append(), buffer_dump(), buffer_free(), buffer_init(), buffer_len(), buffer_ptr(), buffer_put_char(), buffer_put_cstring(), buffer_put_string(), datafellows, debug(), debug2(), error(), hostbased_key_allowed(), key_free(), key_from_blob(), key_type_from_name(), KEY_UNSPEC, key_verify(), logit(), packet_get_string(), PRIVSEP, Authctxt::pw, Authctxt::service, session_id2, session_id2_len, SSH2_MSG_USERAUTH_REQUEST, SSH_BUG_HBSERVICE, Key::type, Authctxt::user, Authctxt::valid, and xfree().

00049 {
00050         Buffer b;
00051         Key *key = NULL;
00052         char *pkalg, *cuser, *chost, *service;
00053         u_char *pkblob, *sig;
00054         u_int alen, blen, slen;
00055         int pktype;
00056         int authenticated = 0;
00057 
00058         if (!authctxt->valid) {
00059                 debug2("userauth_hostbased: disabled because of invalid user");
00060                 return 0;
00061         }
00062         pkalg = packet_get_string(&alen);
00063         pkblob = packet_get_string(&blen);
00064         chost = packet_get_string(NULL);
00065         cuser = packet_get_string(NULL);
00066         sig = packet_get_string(&slen);
00067 
00068         debug("userauth_hostbased: cuser %s chost %s pkalg %s slen %d",
00069             cuser, chost, pkalg, slen);
00070 #ifdef DEBUG_PK
00071         debug("signature:");
00072         buffer_init(&b);
00073         buffer_append(&b, sig, slen);
00074         buffer_dump(&b);
00075         buffer_free(&b);
00076 #endif
00077         pktype = key_type_from_name(pkalg);
00078         if (pktype == KEY_UNSPEC) {
00079                 /* this is perfectly legal */
00080                 logit("userauth_hostbased: unsupported "
00081                     "public key algorithm: %s", pkalg);
00082                 goto done;
00083         }
00084         key = key_from_blob(pkblob, blen);
00085         if (key == NULL) {
00086                 error("userauth_hostbased: cannot decode key: %s", pkalg);
00087                 goto done;
00088         }
00089         if (key->type != pktype) {
00090                 error("userauth_hostbased: type mismatch for decoded key "
00091                     "(received %d, expected %d)", key->type, pktype);
00092                 goto done;
00093         }
00094         service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" :
00095             authctxt->service;
00096         buffer_init(&b);
00097         buffer_put_string(&b, session_id2, session_id2_len);
00098         /* reconstruct packet */
00099         buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST);
00100         buffer_put_cstring(&b, authctxt->user);
00101         buffer_put_cstring(&b, service);
00102         buffer_put_cstring(&b, "hostbased");
00103         buffer_put_string(&b, pkalg, alen);
00104         buffer_put_string(&b, pkblob, blen);
00105         buffer_put_cstring(&b, chost);
00106         buffer_put_cstring(&b, cuser);
00107 #ifdef DEBUG_PK
00108         buffer_dump(&b);
00109 #endif
00110         /* test for allowed key and correct signature */
00111         authenticated = 0;
00112         if (PRIVSEP(hostbased_key_allowed(authctxt->pw, cuser, chost, key)) &&
00113             PRIVSEP(key_verify(key, sig, slen, buffer_ptr(&b),
00114                         buffer_len(&b))) == 1)
00115                 authenticated = 1;
00116 
00117         buffer_free(&b);
00118 done:
00119         debug2("userauth_hostbased: authenticated %d", authenticated);
00120         if (key != NULL)
00121                 key_free(key);
00122         xfree(pkalg);
00123         xfree(pkblob);
00124         xfree(cuser);
00125         xfree(chost);
00126         xfree(sig);
00127         return authenticated;
00128 }


Variable Documentation

Authmethod method_hostbased
 

Initial value:

Definition at line 178 of file auth2-hostbased.c.

ServerOptions options
 

Definition at line 110 of file ssh.c.

u_char* session_id2
 

Definition at line 66 of file sshconnect2.c.

Referenced by do_ssh2_kex(), mm_answer_sign(), mm_get_kex(), monitor_valid_hostbasedblob(), monitor_valid_userblob(), sign_and_send_pubkey(), ssh_kex2(), userauth_hostbased(), and userauth_pubkey().

u_int session_id2_len
 

Definition at line 67 of file sshconnect2.c.

Referenced by do_ssh2_kex(), mm_answer_sign(), mm_get_kex(), monitor_valid_hostbasedblob(), monitor_valid_userblob(), sign_and_send_pubkey(), ssh_kex2(), userauth_hostbased(), and userauth_pubkey().


© sourcejam.com 2005-2008