int sftp_auth_password(struct ssh2_packet *pkt, cmd_rec *pass_cmd,
const char *orig_user, const char *user, const char *service,
unsigned char **buf, uint32_t *buflen, int *send_userauth_fail) {
const char *cipher_algo, *mac_algo;
char *passwd;
int have_new_passwd, res;
struct passwd *pw;
cipher_algo = sftp_cipher_get_read_algo();
mac_algo = sftp_mac_get_read_algo();
if (strncmp(cipher_algo, "none", 5) == 0 ||
strncmp(mac_algo, "none", 5) == 0) {
if (sftp_opts & SFTP_OPT_ALLOW_INSECURE_LOGIN) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"WARNING: cipher algorithm '%s' or MAC algorithm '%s' INSECURE for "
"password authentication (SFTPOption AllowInsecureLogin in effect)",
cipher_algo, mac_algo);
} else {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"cipher algorithm '%s' or MAC algorithm '%s' unacceptable for "
"password authentication, denying password authentication request",
cipher_algo, mac_algo);
*send_userauth_fail = TRUE;
errno = EPERM;
return 0;
}
}
/* XXX We currently don't do anything with this. */
have_new_passwd = sftp_msg_read_bool(pkt->pool, buf, buflen);
if (have_new_passwd) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION, "%s",
"client says they have provided a new password; this functionality "
"is not currently supported");
}
passwd = sftp_msg_read_string(pkt->pool, buf, buflen);
passwd = sftp_utf8_decode_str(pkt->pool, passwd);
pass_cmd->arg = passwd;
if (pr_cmd_dispatch_phase(pass_cmd, PRE_CMD, 0) < 0) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"authentication request for user '%s' blocked by '%s' handler",
orig_user, (char *) pass_cmd->argv[0]);
pr_cmd_dispatch_phase(pass_cmd, POST_CMD_ERR, 0);
pr_cmd_dispatch_phase(pass_cmd, LOG_CMD_ERR, 0);
pr_memscrub(passwd, strlen(passwd));
*send_userauth_fail = TRUE;
errno = EPERM;
return 0;
}
pw = pr_auth_getpwnam(pkt->pool, user);
if (pw == NULL) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"no account for user '%s' found", user);
pr_log_auth(PR_LOG_NOTICE,
"USER %s: no such user found from %s [%s] to %s:%d", user,
session.c->remote_name, pr_netaddr_get_ipstr(session.c->remote_addr),
pr_netaddr_get_ipstr(session.c->local_addr), session.c->local_port);
pr_memscrub(passwd, strlen(passwd));
*send_userauth_fail = TRUE;
errno = ENOENT;
return 0;
}
res = pr_auth_authenticate(pkt->pool, user, passwd);
pr_memscrub(passwd, strlen(passwd));
switch (res) {
case PR_AUTH_OK:
break;
case PR_AUTH_NOPWD:
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"password authentication for user '%s' failed: No such user", user);
pr_log_auth(PR_LOG_NOTICE, "USER %s (Login failed): No such user found",
user);
*send_userauth_fail = TRUE;
errno = ENOENT;
return 0;
case PR_AUTH_BADPWD:
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"password authentication for user '%s' failed: Incorrect password",
user);
pr_log_auth(PR_LOG_NOTICE, "USER %s (Login failed): Incorrect password",
user);
*send_userauth_fail = TRUE;
errno = EINVAL;
return 0;
case PR_AUTH_AGEPWD:
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"password authentication for user '%s' failed: Password expired",
user);
pr_log_auth(PR_LOG_NOTICE, "USER %s (Login failed): Password expired",
user);
*send_userauth_fail = TRUE;
errno = EINVAL;
return 0;
case PR_AUTH_DISABLEDPWD:
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"password authentication for user '%s' failed: Account disabled",
user);
pr_log_auth(PR_LOG_NOTICE, "USER %s (Login failed): Account disabled",
user);
*send_userauth_fail = TRUE;
errno = EINVAL;
return 0;
default:
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"unknown authentication value (%d), returning error", res);
*send_userauth_fail = TRUE;
errno = EINVAL;
return 0;
}
return 1;
}
int sftp_auth_publickey(struct ssh2_packet *pkt, cmd_rec *pass_cmd,
const char *orig_user, const char *user, const char *service, char **buf,
uint32_t *buflen, int *send_userauth_fail) {
int have_signature, pubkey_type;
char *pubkey_algo = NULL, *pubkey_data;
const char *fp = NULL;
uint32_t pubkey_len;
struct passwd *pw;
if (pr_cmd_dispatch_phase(pass_cmd, PRE_CMD, 0) < 0) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"authentication request for user '%s' blocked by '%s' handler",
orig_user, pass_cmd->argv[0]);
pr_cmd_dispatch_phase(pass_cmd, POST_CMD_ERR, 0);
pr_cmd_dispatch_phase(pass_cmd, LOG_CMD_ERR, 0);
*send_userauth_fail = TRUE;
errno = EPERM;
return 0;
}
have_signature = sftp_msg_read_bool(pkt->pool, buf, buflen);
if (sftp_interop_supports_feature(SFTP_SSH2_FEAT_HAVE_PUBKEY_ALGO)) {
pubkey_algo = sftp_msg_read_string(pkt->pool, buf, buflen);
}
pubkey_len = sftp_msg_read_int(pkt->pool, buf, buflen);
pubkey_data = sftp_msg_read_data(pkt->pool, buf, buflen, pubkey_len);
if (pubkey_algo == NULL) {
/* The client did not send the string identifying the public key algorithm.
* Thus we need to extract the algorithm string from the public key data.
*/
pubkey_algo = sftp_msg_read_string(pkt->pool, &pubkey_data, &pubkey_len);
}
pr_trace_msg(trace_channel, 9, "client sent '%s' public key %s",
pubkey_algo, have_signature ? "with signature" : "without signature");
if (strncmp(pubkey_algo, "ssh-rsa", 8) == 0) {
pubkey_type = EVP_PKEY_RSA;
} else if (strncmp(pubkey_algo, "ssh-dss", 8) == 0) {
pubkey_type = EVP_PKEY_DSA;
/* XXX This is where we would add support for X509 public keys, e.g.:
*
* x509v3-ssh-dss
* x509v3-ssh-rsa
* x509v3-sign (older)
*
*/
} else {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"unsupported public key algorithm '%s' requested, rejecting request",
pubkey_algo);
*send_userauth_fail = TRUE;
errno = EINVAL;
return 0;
}
if (sftp_keys_verify_pubkey_type(pkt->pool, pubkey_data, pubkey_len,
pubkey_type) != TRUE) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"unable to verify that given public key matches given '%s' algorithm",
pubkey_algo);
*send_userauth_fail = TRUE;
errno = EINVAL;
return 0;
}
#ifdef OPENSSL_FIPS
if (FIPS_mode()) {
fp = sftp_keys_get_fingerprint(pkt->pool, pubkey_data, pubkey_len,
SFTP_KEYS_FP_DIGEST_SHA1);
if (fp != NULL) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"public key SHA1 fingerprint: %s", fp);
} else {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"error obtaining public key SHA1 fingerprint: %s", strerror(errno));
}
} else {
#endif /* OPENSSL_FIPS */
fp = sftp_keys_get_fingerprint(pkt->pool, pubkey_data, pubkey_len,
SFTP_KEYS_FP_DIGEST_MD5);
if (fp != NULL) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"public key MD5 fingerprint: %s", fp);
} else {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"error obtaining public key MD5 fingerprint: %s", strerror(errno));
}
#ifdef OPENSSL_FIPS
}
#endif /* OPENSSL_FIPS */
pw = pr_auth_getpwnam(pkt->pool, user);
if (pw == NULL) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"no account for user '%s' found", user);
pr_log_auth(PR_LOG_NOTICE,
"USER %s: no such user found from %s [%s] to %s:%d", user,
session.c->remote_name, pr_netaddr_get_ipstr(session.c->remote_addr),
pr_netaddr_get_ipstr(session.c->local_addr), session.c->local_port);
*send_userauth_fail = TRUE;
errno = ENOENT;
return 0;
}
if (!have_signature) {
/* We don't perform the actual authentication just yet; we need to
* let the client know that the pubkey algorithms are acceptable.
*/
if (send_pubkey_ok(pubkey_algo, pubkey_data, pubkey_len) < 0) {
return -1;
}
return 0;
} else {
const unsigned char *id;
char *buf2, *ptr2, *signature_data;
uint32_t buflen2, bufsz2, id_len, signature_len;
/* XXX This should become a more generic "is this key data
* usable/acceptable?" check (and take the pubkey_type parameter), so that
* that is where we would check the validity/usability of an X509v3 cert
* (if a cert), or if the key is on the blacklist (if a key).
*/
if (sftp_blacklist_reject_key(pkt->pool, pubkey_data, pubkey_len)) {
*send_userauth_fail = TRUE;
errno = EPERM;
return 0;
}
signature_len = sftp_msg_read_int(pkt->pool, buf, buflen);
signature_data = sftp_msg_read_data(pkt->pool, buf, buflen, signature_len);
/* The client signed the request as well; we need to authenticate the
* user with the given pubkey now. If that succeeds, we use the
* signature to verify the request. And if that succeeds, then we're
* done authenticating.
*/
/* XXX Need to pass the pubkey_type here as well, so that the
* verification routines can handle different databases of keys/certs.
*
* For X509v3 certs, we will want a way to enforce/restrict which
* user names can be used with the provided cert. Perhaps a database
* mapping cert fingerprints to user names/UIDs? Configurable callback
* check (HOOK?), for modules to enforce.
*/
if (sftp_keystore_verify_user_key(pkt->pool, user, pubkey_data,
pubkey_len) < 0) {
*send_userauth_fail = TRUE;
return 0;
}
/* Make sure the signature matches as well. */
id_len = sftp_session_get_id(&id);
/* Make sure to allocate a buffer large enough to hold the publickey
* signature and data we want to send back.
*/
bufsz2 = buflen2 = pubkey_len + 1024;
ptr2 = buf2 = sftp_msg_getbuf(pkt->pool, bufsz2);
sftp_msg_write_data(&buf2, &buflen2, (char *) id, id_len, TRUE);
sftp_msg_write_byte(&buf2, &buflen2, SFTP_SSH2_MSG_USER_AUTH_REQUEST);
sftp_msg_write_string(&buf2, &buflen2, orig_user);
if (sftp_interop_supports_feature(SFTP_SSH2_FEAT_SERVICE_IN_PUBKEY_SIG)) {
sftp_msg_write_string(&buf2, &buflen2, service);
} else {
sftp_msg_write_string(&buf2, &buflen2, "ssh-userauth");
}
if (sftp_interop_supports_feature(SFTP_SSH2_FEAT_HAVE_PUBKEY_ALGO)) {
sftp_msg_write_string(&buf2, &buflen2, "publickey");
sftp_msg_write_bool(&buf2, &buflen2, TRUE);
sftp_msg_write_string(&buf2, &buflen2, pubkey_algo);
} else {
sftp_msg_write_bool(&buf2, &buflen2, TRUE);
}
sftp_msg_write_data(&buf2, &buflen2, pubkey_data, pubkey_len, TRUE);
if (sftp_keys_verify_signed_data(pkt->pool, pubkey_algo, pubkey_data,
pubkey_len, signature_data, signature_len, (unsigned char *) ptr2,
(bufsz2 - buflen2)) < 0) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"failed to verify '%s' signature on public key auth request for "
"user '%s'", pubkey_algo, orig_user);
*send_userauth_fail = TRUE;
return 0;
}
}
/* Make sure the user is authorized to login. Normally this is checked
* as part of the password verification process, but in the case of
* publickey authentication, there is no password to verify.
*/
if (pr_auth_authorize(pkt->pool, user) != PR_AUTH_OK) {
(void) pr_log_writefile(sftp_logfd, MOD_SFTP_VERSION,
"authentication for user '%s' failed: User not authorized", user);
pr_log_auth(PR_LOG_NOTICE, "USER %s (Login failed): User not authorized "
"for login", user);
*send_userauth_fail = TRUE;
errno = EACCES;
return 0;
}
return 1;
}
