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/* Copyright (C) 2014 mod_auth_gssapi authors - See COPYING for (C) terms */
#include "mod_auth_gssapi.h"
#include "asn1c/GSSSessionData.h"
APLOG_USE_MODULE(auth_gssapi);
static APR_OPTIONAL_FN_TYPE(ap_session_load) *mag_sess_load_fn = NULL;
static APR_OPTIONAL_FN_TYPE(ap_session_get) *mag_sess_get_fn = NULL;
static APR_OPTIONAL_FN_TYPE(ap_session_set) *mag_sess_set_fn = NULL;
void mag_post_config_session(void)
{
mag_sess_load_fn = APR_RETRIEVE_OPTIONAL_FN(ap_session_load);
mag_sess_get_fn = APR_RETRIEVE_OPTIONAL_FN(ap_session_get);
mag_sess_set_fn = APR_RETRIEVE_OPTIONAL_FN(ap_session_set);
}
static apr_status_t mag_session_load(request_rec *req, session_rec **sess)
{
if (mag_sess_load_fn) {
return mag_sess_load_fn(req, sess);
}
return DECLINED;
}
static apr_status_t mag_session_get(request_rec *req, session_rec *sess,
const char *key, const char **value)
{
if (mag_sess_get_fn) {
return mag_sess_get_fn(req, sess, key, value);
}
return DECLINED;
}
static apr_status_t mag_session_set(request_rec *req, session_rec *sess,
const char *key, const char *value)
{
if (mag_sess_set_fn) {
return mag_sess_set_fn(req, sess, key, value);
}
return DECLINED;
}
static bool encode_GSSSessionData(apr_pool_t *mempool,
GSSSessionData_t *gsessdata,
unsigned char **buf, int *len)
{
asn_enc_rval_t rval;
unsigned char *buffer = NULL;
size_t buflen;
bool ret = false;
/* dry run to compute the size */
rval = der_encode(&asn_DEF_GSSSessionData, gsessdata, NULL, NULL);
if (rval.encoded == -1) goto done;
buflen = rval.encoded;
buffer = apr_pcalloc(mempool, buflen);
/* now for real */
rval = der_encode_to_buffer(&asn_DEF_GSSSessionData,
gsessdata, buffer, buflen);
if (rval.encoded == -1) goto done;
*buf = buffer;
*len = buflen;
ret = true;
done:
return ret;
}
static GSSSessionData_t *decode_GSSSessionData(void *buf, size_t len)
{
GSSSessionData_t *gsessdata = NULL;
asn_dec_rval_t rval;
rval = ber_decode(NULL, &asn_DEF_GSSSessionData,
(void **)&gsessdata, buf, len);
if (rval.code == RC_OK) {
return gsessdata;
}
return NULL;
}
#define MAG_BEARER_KEY "MagBearerToken"
void mag_check_session(request_rec *req,
struct mag_config *cfg, struct mag_conn **conn)
{
struct mag_conn *mc;
apr_status_t rc;
session_rec *sess = NULL;
const char *sessval = NULL;
int declen;
struct databuf ctxbuf = { 0 };
struct databuf cipherbuf = { 0 };
GSSSessionData_t *gsessdata;
time_t expiration;
rc = mag_session_load(req, &sess);
if (rc != OK || sess == NULL) {
ap_log_rerror(APLOG_MARK, APLOG_INFO|APLOG_NOERRNO, 0, req,
"Sessions not available, no cookies!");
return;
}
mc = *conn;
if (!mc) {
mc = apr_pcalloc(req->pool, sizeof(struct mag_conn));
if (!mc) return;
mc->parent = req->pool;
*conn = mc;
}
rc = mag_session_get(req, sess, MAG_BEARER_KEY, &sessval);
if (rc != OK) {
ap_log_rerror(APLOG_MARK, APLOG_ERR|APLOG_NOERRNO, 0, req,
"Failed to get session data!");
return;
}
if (!sessval) {
/* no session established, just return */
return;
}
if (!cfg->mag_skey) {
ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, req,
"Session key not available, no cookies!");
/* we do not have a key, just return */
return;
}
/* decode it */
declen = apr_base64_decode_len(sessval);
cipherbuf.value = apr_palloc(req->pool, declen);
if (!cipherbuf.value) return;
cipherbuf.length = (int)apr_base64_decode((char *)cipherbuf.value, sessval);
rc = UNSEAL_BUFFER(req->pool, cfg->mag_skey, &cipherbuf, &ctxbuf);
if (rc != OK) {
ap_log_rerror(APLOG_MARK, APLOG_ERR|APLOG_NOERRNO, 0, req,
"Failed to unseal session data!");
return;
}
gsessdata = decode_GSSSessionData(ctxbuf.value, ctxbuf.length);
if (!gsessdata) {
ap_log_rerror(APLOG_MARK, APLOG_ERR|APLOG_NOERRNO, 0, req,
"Failed to unpack session data!");
return;
}
/* get time */
expiration = gsessdata->expiration;
if (expiration < time(NULL)) {
/* credentials fully expired, return nothing */
goto done;
}
/* user name */
mc->user_name = apr_pstrndup(mc->parent,
(char *)gsessdata->username.buf,
gsessdata->username.size);
if (!mc->user_name) goto done;
/* gssapi name */
mc->gss_name = apr_pstrndup(mc->parent,
(char *)gsessdata->gssname.buf,
gsessdata->gssname.size);
if (!mc->gss_name) goto done;
/* OK we have a valid token */
mc->established = true;
done:
ASN_STRUCT_FREE(asn_DEF_GSSSessionData, gsessdata);
}
void mag_attempt_session(request_rec *req,
struct mag_config *cfg, struct mag_conn *mc)
{
session_rec *sess = NULL;
struct databuf plainbuf = { 0 };
struct databuf cipherbuf = { 0 };
struct databuf ctxbuf = { 0 };
GSSSessionData_t gsessdata = { 0 };
apr_status_t rc;
bool ret;
/* we save the session only if the authentication is established */
if (!mc->established) return;
rc = mag_session_load(req, &sess);
if (rc != OK || sess == NULL) {
ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, req,
"Sessions not available, can't send cookies!");
return;
}
if (!cfg->mag_skey) {
ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, req,
"Session key not available, generating new one.");
rc = SEAL_KEY_CREATE(cfg->pool, &cfg->mag_skey, NULL);
if (rc != OK) {
ap_log_rerror(APLOG_MARK, APLOG_ERR|APLOG_NOERRNO, 0, req,
"Failed to create sealing key!");
return;
}
}
gsessdata.expiration = mc->expiration;
if (OCTET_STRING_fromString(&gsessdata.username, mc->user_name) != 0)
goto done;
if (OCTET_STRING_fromString(&gsessdata.gssname, mc->gss_name) != 0)
goto done;
ret = encode_GSSSessionData(req->pool, &gsessdata,
&plainbuf.value, &plainbuf.length);
if (ret == false) {
ap_log_rerror(APLOG_MARK, APLOG_ERR|APLOG_NOERRNO, 0, req,
"Failed to pack session data!");
goto done;
}
rc = SEAL_BUFFER(req->pool, cfg->mag_skey, &plainbuf, &cipherbuf);
if (rc != OK) {
ap_log_rerror(APLOG_MARK, APLOG_ERR|APLOG_NOERRNO, 0, req,
"Failed to seal session data!");
goto done;
}
ctxbuf.length = apr_base64_encode_len(cipherbuf.length);
ctxbuf.value = apr_pcalloc(req->pool, ctxbuf.length);
if (!ctxbuf.value) goto done;
ctxbuf.length = apr_base64_encode((char *)ctxbuf.value,
(char *)cipherbuf.value,
cipherbuf.length);
rc = mag_session_set(req, sess, MAG_BEARER_KEY, (char *)ctxbuf.value);
if (rc != OK) {
ap_log_rerror(APLOG_MARK, APLOG_ERR|APLOG_NOERRNO, 0, req,
"Failed to set session data!");
}
done:
ASN_STRUCT_FREE_CONTENTS_ONLY(asn_DEF_GSSSessionData, &gsessdata);
}
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