version 1.22, 2001/03/23 12:02:49 |
version 1.22.2.3, 2002/06/02 22:56:09 |
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#include "servconf.h" |
#include "servconf.h" |
#include "compat.h" |
#include "compat.h" |
#include "auth.h" |
#include "auth.h" |
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#include "channels.h" |
#include "session.h" |
#include "session.h" |
#include "misc.h" |
#include "uidswap.h" |
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#include "monitor_wrap.h" |
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/* import */ |
/* import */ |
extern ServerOptions options; |
extern ServerOptions options; |
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/* |
/* |
* convert ssh auth msg type into description |
* convert ssh auth msg type into description |
*/ |
*/ |
char * |
static char * |
get_authname(int type) |
get_authname(int type) |
{ |
{ |
static char buf[1024]; |
static char buf[1024]; |
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case SSH_CMSG_AUTH_TIS: |
case SSH_CMSG_AUTH_TIS: |
case SSH_CMSG_AUTH_TIS_RESPONSE: |
case SSH_CMSG_AUTH_TIS_RESPONSE: |
return "challenge-response"; |
return "challenge-response"; |
#ifdef KRB4 |
#if defined(KRB4) || defined(KRB5) |
case SSH_CMSG_AUTH_KERBEROS: |
case SSH_CMSG_AUTH_KERBEROS: |
return "kerberos"; |
return "kerberos"; |
#endif |
#endif |
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* read packets, try to authenticate the user and |
* read packets, try to authenticate the user and |
* return only if authentication is successful |
* return only if authentication is successful |
*/ |
*/ |
void |
static void |
do_authloop(Authctxt *authctxt) |
do_authloop(Authctxt *authctxt) |
{ |
{ |
int authenticated = 0; |
int authenticated = 0; |
u_int bits; |
u_int bits; |
RSA *client_host_key; |
Key *client_host_key; |
BIGNUM *n; |
BIGNUM *n; |
char *client_user, *password; |
char *client_user, *password; |
char info[1024]; |
char info[1024]; |
u_int dlen; |
u_int dlen; |
int plen, nlen, elen; |
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u_int ulen; |
u_int ulen; |
int type = 0; |
int type = 0; |
struct passwd *pw = authctxt->pw; |
struct passwd *pw = authctxt->pw; |
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debug("Attempting authentication for %s%.100s.", |
debug("Attempting authentication for %s%.100s.", |
authctxt->valid ? "" : "illegal user ", authctxt->user); |
authctxt->valid ? "" : "illegal user ", authctxt->user); |
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/* If the user has no password, accept authentication immediately. */ |
/* If the user has no password, accept authentication immediately. */ |
if (options.password_authentication && |
if (options.password_authentication && |
#ifdef KRB4 |
#if defined(KRB4) || defined(KRB5) |
(!options.kerberos_authentication || options.kerberos_or_local_passwd) && |
(!options.kerberos_authentication || options.kerberos_or_local_passwd) && |
#endif |
#endif |
auth_password(authctxt, "")) { |
PRIVSEP(auth_password(authctxt, ""))) { |
auth_log(authctxt, 1, "without authentication", ""); |
auth_log(authctxt, 1, "without authentication", ""); |
return; |
return; |
} |
} |
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info[0] = '\0'; |
info[0] = '\0'; |
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/* Get a packet from the client. */ |
/* Get a packet from the client. */ |
type = packet_read(&plen); |
type = packet_read(); |
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/* Process the packet. */ |
/* Process the packet. */ |
switch (type) { |
switch (type) { |
#ifdef AFS |
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case SSH_CMSG_HAVE_KERBEROS_TGT: |
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if (!options.kerberos_tgt_passing) { |
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verbose("Kerberos tgt passing disabled."); |
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break; |
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} else { |
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/* Accept Kerberos tgt. */ |
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char *tgt = packet_get_string(&dlen); |
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packet_integrity_check(plen, 4 + dlen, type); |
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if (!auth_kerberos_tgt(pw, tgt)) |
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verbose("Kerberos tgt REFUSED for %.100s", authctxt->user); |
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xfree(tgt); |
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} |
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continue; |
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case SSH_CMSG_HAVE_AFS_TOKEN: |
#if defined(KRB4) || defined(KRB5) |
if (!options.afs_token_passing || !k_hasafs()) { |
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verbose("AFS token passing disabled."); |
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break; |
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} else { |
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/* Accept AFS token. */ |
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char *token_string = packet_get_string(&dlen); |
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packet_integrity_check(plen, 4 + dlen, type); |
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if (!auth_afs_token(pw, token_string)) |
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verbose("AFS token REFUSED for %.100s", authctxt->user); |
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xfree(token_string); |
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} |
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continue; |
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#endif /* AFS */ |
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#ifdef KRB4 |
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case SSH_CMSG_AUTH_KERBEROS: |
case SSH_CMSG_AUTH_KERBEROS: |
if (!options.kerberos_authentication) { |
if (!options.kerberos_authentication) { |
verbose("Kerberos authentication disabled."); |
verbose("Kerberos authentication disabled."); |
break; |
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} else { |
} else { |
/* Try Kerberos v4 authentication. */ |
char *kdata = packet_get_string(&dlen); |
KTEXT_ST auth; |
packet_check_eom(); |
char *tkt_user = NULL; |
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char *kdata = packet_get_string((u_int *) &auth.length); |
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packet_integrity_check(plen, 4 + auth.length, type); |
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if (authctxt->valid) { |
if (kdata[0] == 4) { /* KRB_PROT_VERSION */ |
if (auth.length < MAX_KTXT_LEN) |
#ifdef KRB4 |
memcpy(auth.dat, kdata, auth.length); |
KTEXT_ST tkt; |
authenticated = auth_krb4(pw->pw_name, &auth, &tkt_user); |
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if (authenticated) { |
tkt.length = dlen; |
snprintf(info, sizeof info, |
if (tkt.length < MAX_KTXT_LEN) |
" tktuser %.100s", tkt_user); |
memcpy(tkt.dat, kdata, tkt.length); |
xfree(tkt_user); |
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if (auth_krb4(authctxt, &tkt, &client_user)) { |
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authenticated = 1; |
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snprintf(info, sizeof(info), |
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" tktuser %.100s", |
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client_user); |
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xfree(client_user); |
} |
} |
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#endif /* KRB4 */ |
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} else { |
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#ifdef KRB5 |
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krb5_data tkt; |
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tkt.length = dlen; |
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tkt.data = kdata; |
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if (auth_krb5(authctxt, &tkt, &client_user)) { |
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authenticated = 1; |
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snprintf(info, sizeof(info), |
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" tktuser %.100s", |
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client_user); |
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xfree(client_user); |
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} |
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#endif /* KRB5 */ |
} |
} |
xfree(kdata); |
xfree(kdata); |
} |
} |
break; |
break; |
#endif /* KRB4 */ |
#endif /* KRB4 || KRB5 */ |
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#if defined(AFS) || defined(KRB5) |
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/* XXX - punt on backward compatibility here. */ |
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case SSH_CMSG_HAVE_KERBEROS_TGT: |
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packet_send_debug("Kerberos TGT passing disabled before authentication."); |
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break; |
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#ifdef AFS |
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case SSH_CMSG_HAVE_AFS_TOKEN: |
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packet_send_debug("AFS token passing disabled before authentication."); |
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break; |
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#endif /* AFS */ |
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#endif /* AFS || KRB5 */ |
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case SSH_CMSG_AUTH_RHOSTS: |
case SSH_CMSG_AUTH_RHOSTS: |
if (!options.rhosts_authentication) { |
if (!options.rhosts_authentication) { |
verbose("Rhosts authentication disabled."); |
verbose("Rhosts authentication disabled."); |
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* IP-spoofing on a local network.) |
* IP-spoofing on a local network.) |
*/ |
*/ |
client_user = packet_get_string(&ulen); |
client_user = packet_get_string(&ulen); |
packet_integrity_check(plen, 4 + ulen, type); |
packet_check_eom(); |
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/* Try to authenticate using /etc/hosts.equiv and .rhosts. */ |
/* Try to authenticate using /etc/hosts.equiv and .rhosts. */ |
authenticated = auth_rhosts(pw, client_user); |
authenticated = auth_rhosts(pw, client_user); |
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client_user = packet_get_string(&ulen); |
client_user = packet_get_string(&ulen); |
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/* Get the client host key. */ |
/* Get the client host key. */ |
client_host_key = RSA_new(); |
client_host_key = key_new(KEY_RSA1); |
if (client_host_key == NULL) |
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fatal("RSA_new failed"); |
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client_host_key->e = BN_new(); |
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client_host_key->n = BN_new(); |
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if (client_host_key->e == NULL || client_host_key->n == NULL) |
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fatal("BN_new failed"); |
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bits = packet_get_int(); |
bits = packet_get_int(); |
packet_get_bignum(client_host_key->e, &elen); |
packet_get_bignum(client_host_key->rsa->e); |
packet_get_bignum(client_host_key->n, &nlen); |
packet_get_bignum(client_host_key->rsa->n); |
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if (bits != BN_num_bits(client_host_key->n)) |
if (bits != BN_num_bits(client_host_key->rsa->n)) |
verbose("Warning: keysize mismatch for client_host_key: " |
verbose("Warning: keysize mismatch for client_host_key: " |
"actual %d, announced %d", BN_num_bits(client_host_key->n), bits); |
"actual %d, announced %d", |
packet_integrity_check(plen, (4 + ulen) + 4 + elen + nlen, type); |
BN_num_bits(client_host_key->rsa->n), bits); |
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packet_check_eom(); |
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authenticated = auth_rhosts_rsa(pw, client_user, client_host_key); |
authenticated = auth_rhosts_rsa(pw, client_user, |
RSA_free(client_host_key); |
client_host_key); |
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key_free(client_host_key); |
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snprintf(info, sizeof info, " ruser %.100s", client_user); |
snprintf(info, sizeof info, " ruser %.100s", client_user); |
xfree(client_user); |
xfree(client_user); |
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break; |
break; |
} |
} |
/* RSA authentication requested. */ |
/* RSA authentication requested. */ |
n = BN_new(); |
if ((n = BN_new()) == NULL) |
packet_get_bignum(n, &nlen); |
fatal("do_authloop: BN_new failed"); |
packet_integrity_check(plen, nlen, type); |
packet_get_bignum(n); |
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packet_check_eom(); |
authenticated = auth_rsa(pw, n); |
authenticated = auth_rsa(pw, n); |
BN_clear_free(n); |
BN_clear_free(n); |
break; |
break; |
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* not visible to an outside observer. |
* not visible to an outside observer. |
*/ |
*/ |
password = packet_get_string(&dlen); |
password = packet_get_string(&dlen); |
packet_integrity_check(plen, 4 + dlen, type); |
packet_check_eom(); |
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/* Try authentication with the password. */ |
/* Try authentication with the password. */ |
authenticated = auth_password(authctxt, password); |
authenticated = PRIVSEP(auth_password(authctxt, password)); |
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memset(password, 0, strlen(password)); |
memset(password, 0, strlen(password)); |
xfree(password); |
xfree(password); |
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case SSH_CMSG_AUTH_TIS: |
case SSH_CMSG_AUTH_TIS: |
debug("rcvd SSH_CMSG_AUTH_TIS"); |
debug("rcvd SSH_CMSG_AUTH_TIS"); |
if (options.challenge_reponse_authentication == 1) { |
if (options.challenge_response_authentication == 1) { |
char *challenge = get_challenge(authctxt, authctxt->style); |
char *challenge = get_challenge(authctxt); |
if (challenge != NULL) { |
if (challenge != NULL) { |
debug("sending challenge '%s'", challenge); |
debug("sending challenge '%s'", challenge); |
packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); |
packet_start(SSH_SMSG_AUTH_TIS_CHALLENGE); |
packet_put_cstring(challenge); |
packet_put_cstring(challenge); |
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xfree(challenge); |
packet_send(); |
packet_send(); |
packet_write_wait(); |
packet_write_wait(); |
continue; |
continue; |
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break; |
break; |
case SSH_CMSG_AUTH_TIS_RESPONSE: |
case SSH_CMSG_AUTH_TIS_RESPONSE: |
debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE"); |
debug("rcvd SSH_CMSG_AUTH_TIS_RESPONSE"); |
if (options.challenge_reponse_authentication == 1) { |
if (options.challenge_response_authentication == 1) { |
char *response = packet_get_string(&dlen); |
char *response = packet_get_string(&dlen); |
debug("got response '%s'", response); |
debug("got response '%s'", response); |
packet_integrity_check(plen, 4 + dlen, type); |
packet_check_eom(); |
authenticated = verify_response(authctxt, response); |
authenticated = verify_response(authctxt, response); |
memset(response, 'r', dlen); |
memset(response, 'r', dlen); |
xfree(response); |
xfree(response); |
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* Performs authentication of an incoming connection. Session key has already |
* Performs authentication of an incoming connection. Session key has already |
* been exchanged and encryption is enabled. |
* been exchanged and encryption is enabled. |
*/ |
*/ |
void |
Authctxt * |
do_authentication() |
do_authentication(void) |
{ |
{ |
Authctxt *authctxt; |
Authctxt *authctxt; |
struct passwd *pw; |
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int plen; |
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u_int ulen; |
u_int ulen; |
char *user, *style = NULL; |
char *user, *style = NULL; |
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/* Get the name of the user that we wish to log in as. */ |
/* Get the name of the user that we wish to log in as. */ |
packet_read_expect(&plen, SSH_CMSG_USER); |
packet_read_expect(SSH_CMSG_USER); |
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/* Get the user name. */ |
/* Get the user name. */ |
user = packet_get_string(&ulen); |
user = packet_get_string(&ulen); |
packet_integrity_check(plen, (4 + ulen), SSH_CMSG_USER); |
packet_check_eom(); |
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if ((style = strchr(user, ':')) != NULL) |
if ((style = strchr(user, ':')) != NULL) |
*style++ = 0; |
*style++ = '\0'; |
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#ifdef KRB5 |
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/* XXX - SSH.com Kerberos v5 braindeath. */ |
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if ((datafellows & SSH_BUG_K5USER) && |
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options.kerberos_authentication) { |
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char *p; |
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if ((p = strchr(user, '@')) != NULL) |
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*p = '\0'; |
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} |
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#endif |
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authctxt = authctxt_new(); |
authctxt = authctxt_new(); |
authctxt->user = user; |
authctxt->user = user; |
authctxt->style = style; |
authctxt->style = style; |
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/* Verify that the user is a valid user. */ |
/* Verify that the user is a valid user. */ |
pw = getpwnam(user); |
if ((authctxt->pw = PRIVSEP(getpwnamallow(user))) != NULL) |
if (pw && allowed_user(pw)) { |
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authctxt->valid = 1; |
authctxt->valid = 1; |
pw = pwcopy(pw); |
else |
} else { |
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debug("do_authentication: illegal user %s", user); |
debug("do_authentication: illegal user %s", user); |
pw = NULL; |
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} |
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authctxt->pw = pw; |
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setproctitle("%s", pw ? user : "unknown"); |
setproctitle("%s%s", authctxt->pw ? user : "unknown", |
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use_privsep ? " [net]" : ""); |
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/* |
/* |
* If we are not running as root, the user must have the same uid as |
* If we are not running as root, the user must have the same uid as |
* the server. |
* the server. |
*/ |
*/ |
if (getuid() != 0 && pw && pw->pw_uid != getuid()) |
if (!use_privsep && getuid() != 0 && authctxt->pw && |
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authctxt->pw->pw_uid != getuid()) |
packet_disconnect("Cannot change user when server not running as root."); |
packet_disconnect("Cannot change user when server not running as root."); |
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/* |
/* |
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packet_send(); |
packet_send(); |
packet_write_wait(); |
packet_write_wait(); |
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/* Perform session preparation. */ |
return (authctxt); |
do_authenticated(authctxt); |
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} |
} |