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mod_auth_gssapi.c
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/* Copyright (C) 2014, 2016, 2020 mod_auth_gssapi contributors
* See COPYING for (C) terms */
#include "mod_auth_gssapi.h"
#include "mag_parse.h"
#include <sys/stat.h>
#include <sys/types.h>
const gss_OID_desc gss_mech_spnego = {
6, "\x2b\x06\x01\x05\x05\x02"
};
#ifdef HAVE_GSSAPI_GSSAPI_NTLMSSP_H
const gss_OID_desc gss_mech_ntlmssp_desc = {
GSS_NTLMSSP_OID_LENGTH, GSS_NTLMSSP_OID_STRING
};
gss_const_OID gss_mech_ntlmssp = &gss_mech_ntlmssp_desc;
const gss_OID_set_desc gss_mech_set_ntlmssp_desc = {
1, discard_const(&gss_mech_ntlmssp_desc)
};
gss_const_OID_set gss_mech_set_ntlmssp = &gss_mech_set_ntlmssp_desc;
#else
gss_OID gss_mech_ntlmssp = GSS_C_NO_OID;
gss_OID_set gss_mech_set_ntlmssp = GSS_C_NO_OID_SET;
#endif
#define MOD_AUTH_GSSAPI_VERSION PACKAGE_NAME "/" PACKAGE_VERSION
module AP_MODULE_DECLARE_DATA auth_gssapi_module;
APLOG_USE_MODULE(auth_gssapi);
static char *mag_status(apr_pool_t *pool, int type, uint32_t err)
{
uint32_t maj_ret, min_ret;
gss_buffer_desc text;
uint32_t msg_ctx;
char *msg_ret;
int len;
msg_ret = NULL;
msg_ctx = 0;
do {
maj_ret = gss_display_status(&min_ret, err, type,
GSS_C_NO_OID, &msg_ctx, &text);
if (maj_ret != GSS_S_COMPLETE) {
return msg_ret;
}
len = text.length;
if (msg_ret) {
msg_ret = apr_psprintf(pool, "%s, %*s",
msg_ret, len, (char *)text.value);
} else {
msg_ret = apr_psprintf(pool, "%*s", len, (char *)text.value);
}
gss_release_buffer(&min_ret, &text);
} while (msg_ctx != 0);
return msg_ret;
}
char *mag_error(apr_pool_t *pool, const char *msg, uint32_t maj, uint32_t min)
{
char *msg_maj;
char *msg_min;
msg_maj = mag_status(pool, GSS_C_GSS_CODE, maj);
msg_min = mag_status(pool, GSS_C_MECH_CODE, min);
return apr_psprintf(pool, "%s: [%s (%s)]", msg, msg_maj, msg_min);
}
enum mag_err_code {
MAG_NO_AUTH = 1,
MAG_GSS_ERR,
MAG_INTERNAL,
MAG_AUTH_NOT_ALLOWED
};
static const char *mag_err_text(enum mag_err_code err)
{
switch (err) {
case MAG_NO_AUTH:
return "NO AUTH DATA";
case MAG_GSS_ERR:
return "GSS ERROR";
case MAG_INTERNAL:
return "INTERNAL ERROR";
case MAG_AUTH_NOT_ALLOWED:
return "AUTH NOT ALLOWED";
default:
return "INVALID ERROR CODE";
}
}
static void mag_post_info(request_rec *req, struct mag_config *cfg,
enum mag_err_code err, const char *msg)
{
if (cfg->enverrs) {
mag_publish_error(req, 0, 0, msg, mag_err_text(err));
}
ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, req, "%s %s", mag_err_text(err),
msg);
}
static void mag_post_error(request_rec *req, struct mag_config *cfg,
enum mag_err_code err, uint32_t maj, uint32_t min,
const char *msg)
{
const char *text = NULL;
if (maj)
text = mag_error(req->pool, msg, maj, min);
if (cfg->enverrs)
mag_publish_error(req, maj, min, text ? text : msg, mag_err_text(err));
ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, req, "%s %s", mag_err_text(err),
text ? text : msg);
}
static APR_OPTIONAL_FN_TYPE(ssl_is_https) *mag_is_https = NULL;
static int mag_post_config(apr_pool_t *cfgpool, apr_pool_t *log,
apr_pool_t *temp, server_rec *s)
{
/* FIXME: create mutex to deal with connections and contexts ? */
mag_is_https = APR_RETRIEVE_OPTIONAL_FN(ssl_is_https);
mag_post_config_session();
ap_add_version_component(cfgpool, MOD_AUTH_GSSAPI_VERSION);
return OK;
}
static int mag_pre_connection(conn_rec *c, void *csd)
{
struct mag_conn *mc;
mc = mag_new_conn_ctx(c->pool);
mc->is_preserved = true;
ap_set_module_config(c->conn_config, &auth_gssapi_module, (void*)mc);
return OK;
}
static apr_status_t mag_conn_destroy(void *ptr)
{
struct mag_conn *mc = (struct mag_conn *)ptr;
uint32_t min;
if (mc->ctx) {
(void)gss_delete_sec_context(&min, &mc->ctx, GSS_C_NO_BUFFER);
}
return APR_SUCCESS;
}
struct mag_conn *mag_new_conn_ctx(apr_pool_t *pool)
{
struct mag_conn *mc;
mc = apr_pcalloc(pool, sizeof(struct mag_conn));
apr_pool_create(&mc->pool, pool);
mc->env = apr_table_make(mc->pool, 1);
/* register the context in the memory pool, so it can be freed
* when the connection/request is terminated */
apr_pool_cleanup_register(mc->pool, (void *)mc,
mag_conn_destroy, apr_pool_cleanup_null);
return mc;
}
static void mag_conn_clear(struct mag_conn *mc)
{
(void)mag_conn_destroy(mc);
apr_pool_t *temp;
apr_pool_clear(mc->pool);
temp = mc->pool;
memset(mc, 0, sizeof(struct mag_conn));
mc->pool = temp;
mc->env = apr_table_make(mc->pool, 1);
}
static bool mag_conn_is_https(conn_rec *c)
{
if (mag_is_https) {
if (mag_is_https(c)) return true;
}
return false;
}
static char *get_ccache_name(request_rec *req, char *dir, const char *name,
bool use_unique, apr_pool_t *pool);
static bool mag_acquire_creds(request_rec *req,
struct mag_config *cfg,
gss_OID_set desired_mechs,
gss_cred_usage_t cred_usage,
gss_cred_id_t *creds,
gss_OID_set *actual_mechs)
{
gss_name_t acceptor_name = GSS_C_NO_NAME;
uint32_t maj, min;
bool ret;
if (cfg->acceptor_name_from_req) {
gss_buffer_desc bufnam;
bufnam.value = apr_psprintf(req->pool, "HTTP@%s", req->hostname);
bufnam.length = strlen(bufnam.value);
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, req, "GSS Server Name: %s",
(char *)bufnam.value);
maj = gss_import_name(&min, &bufnam, GSS_C_NT_HOSTBASED_SERVICE,
&acceptor_name);
if (GSS_ERROR(maj)) {
mag_post_error(req, cfg, MAG_GSS_ERR, maj, min,
"gss_import_name() failed to import hostnname");
return false;
}
} else {
acceptor_name = cfg->acceptor_name;
}
#ifdef HAVE_CRED_STORE
gss_const_key_value_set_t store = NULL;
/* When using multiple names, we need to use individual separate ccaches
* for each principal or gss_acquire_cred() on the default ccache will
* fail when names don't match. This is needed only for the s4u2proxy
* case, where we try to acquire proxy credentials. The lucky thing is
* that in this case we require the use of a delegated creedntials
* directory, so we just use this directory to also hold permanent ccaches
* for individual acceptor names. */
if (cfg->acceptor_name_from_req && cfg->use_s4u2proxy &&
cfg->deleg_ccache_dir) {
gss_key_value_set_desc *s;
bool add = true;
char *ccname;
char *special_name;
special_name = apr_psprintf(req->pool, "acceptor_%s", req->hostname);
ccname = get_ccache_name(req, cfg->deleg_ccache_dir, special_name,
false, req->pool);
s = apr_pcalloc(req->pool, sizeof(gss_key_value_set_desc));
s->count = cfg->cred_store->count;
s->elements = apr_pcalloc(req->pool,
(s->count + 1) *
sizeof(gss_key_value_element_desc));
for (size_t i = 0; i < s->count; i++) {
gss_key_value_element_desc *el = &cfg->cred_store->elements[i];
s->elements[i].key = el->key;
if (strcmp(el->key, "ccache") == 0) {
s->elements[i].value = ccname;
add = false;
} else {
s->elements[i].value = el->value;
}
}
if (add) {
s->elements[s->count].key = "ccache";
s->elements[s->count].value = ccname;
s->count++;
}
store = s;
} else {
store = cfg->cred_store;
}
maj = gss_acquire_cred_from(&min, acceptor_name, GSS_C_INDEFINITE,
desired_mechs, cred_usage, store, creds,
actual_mechs, NULL);
#else
maj = gss_acquire_cred(&min, acceptor_name, GSS_C_INDEFINITE,
desired_mechs, cred_usage, creds,
actual_mechs, NULL);
#endif
if (GSS_ERROR(maj)) {
mag_post_error(req, cfg, MAG_GSS_ERR, maj, min,
"gss_acquire_cred[_from]() failed to get server creds");
ret = false;
} else {
ret = true;
}
if (cfg->acceptor_name_from_req) {
gss_release_name(&min, &acceptor_name);
}
return ret;
}
#ifdef HAVE_CRED_STORE
static char *escape(apr_pool_t *pool, const char *name,
char find, const char *replace)
{
char *escaped = NULL;
char *namecopy;
char *n;
char *p;
namecopy = apr_pstrdup(pool, name);
p = strchr(namecopy, find);
if (!p) return namecopy;
/* first segment */
n = namecopy;
while (p) {
/* terminate previous segment */
*p = '\0';
if (escaped) {
escaped = apr_pstrcat(pool, escaped, n, replace, NULL);
} else {
escaped = apr_pstrcat(pool, n, replace, NULL);
}
/* move to next segment */
n = p + 1;
p = strchr(n, find);
}
/* append last segment if any */
if (*n) {
escaped = apr_pstrcat(pool, escaped, n, NULL);
}
return escaped;
}
static char *get_ccache_name(request_rec *req, char *dir, const char *name,
bool use_unique, apr_pool_t *pool)
{
char *ccname, *escaped;
int ccachefd;
mode_t umask_save;
/* We need to escape away '/', we can't have path separators in
* a ccache file name */
/* first double escape the esacping char (~) if any */
escaped = escape(req->pool, name, '~', "~~");
/* then escape away the separator (/) if any */
escaped = escape(req->pool, escaped, '/', "~");
if (use_unique == false) {
return apr_psprintf(pool, "%s/%s", dir, escaped);
}
ccname = apr_psprintf(pool, "%s/%s-XXXXXX", dir, escaped);
umask_save = umask(0177);
ccachefd = mkstemp(ccname);
umask(umask_save);
if (ccachefd == -1) {
ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, req,
"creating unique ccache file %s failed", ccname);
return NULL;
}
close(ccachefd);
return ccname;
}
static void mag_store_deleg_creds(request_rec *req, const char *ccname,
gss_cred_id_t delegated_cred)
{
gss_key_value_element_desc element;
gss_key_value_set_desc store;
uint32_t maj, min;
element.key = "ccache";
store.elements = &element;
store.count = 1;
element.value = apr_psprintf(req->pool, "FILE:%s", ccname);
maj = gss_store_cred_into(&min, delegated_cred, GSS_C_INITIATE,
GSS_C_NULL_OID, 1, 1, &store, NULL, NULL);
if (GSS_ERROR(maj)) {
ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, req, "%s",
mag_error(req->pool, "failed to store delegated creds",
maj, min));
}
}
#endif
static bool parse_auth_header(apr_pool_t *pool, const char **auth_header,
gss_buffer_t value)
{
char *auth_header_value;
auth_header_value = ap_getword_white(pool, auth_header);
if (!auth_header_value) return false;
value->length = apr_base64_decode_len(auth_header_value) + 1;
value->value = apr_pcalloc(pool, value->length);
if (!value->value) return false;
value->length = apr_base64_decode(value->value, auth_header_value);
return true;
}
static bool is_mech_allowed(gss_OID_set allowed_mechs, gss_const_OID mech,
bool multi_step_supported)
{
if (mech == GSS_C_NO_OID) return false;
if (!multi_step_supported && gss_oid_equal(gss_mech_ntlmssp, mech))
return false;
if (allowed_mechs == GSS_C_NO_OID_SET) return true;
for (int i = 0; i < allowed_mechs->count; i++) {
if (gss_oid_equal(&allowed_mechs->elements[i], mech)) {
return true;
}
}
return false;
}
#define AUTH_TYPE_NEGOTIATE 0
#define AUTH_TYPE_BASIC 1
#define AUTH_TYPE_RAW_NTLM 2
#define AUTH_TYPE_IMPERSONATE 3
const char *auth_types[] = {
"Negotiate",
"Basic",
"NTLM",
"Impersonate",
NULL
};
const char *mag_str_auth_type(int auth_type)
{
return auth_types[auth_type];
}
gss_OID_set mag_filter_unwanted_mechs(gss_OID_set src)
{
gss_const_OID unwanted_mechs[] = {
&gss_mech_spnego,
gss_mech_krb5_old,
gss_mech_krb5_wrong,
gss_mech_iakerb,
GSS_C_NO_OID
};
gss_OID_set dst;
uint32_t maj, min;
int present = 0;
if (src == GSS_C_NO_OID_SET) return GSS_C_NO_OID_SET;
for (int i = 0; unwanted_mechs[i] != GSS_C_NO_OID; i++) {
maj = gss_test_oid_set_member(&min,
discard_const(unwanted_mechs[i]),
src, &present);
if (present) break;
}
if (present) {
maj = gss_create_empty_oid_set(&min, &dst);
if (maj != GSS_S_COMPLETE) {
return GSS_C_NO_OID_SET;
}
for (int i = 0; i < src->count; i++) {
present = 0;
for (int j = 0; unwanted_mechs[j] != GSS_C_NO_OID; j++) {
if (gss_oid_equal(&src->elements[i], unwanted_mechs[j])) {
present = 1;
break;
}
}
if (present) continue;
maj = gss_add_oid_set_member(&min, &src->elements[i], &dst);
if (maj != GSS_S_COMPLETE) {
gss_release_oid_set(&min, &dst);
return GSS_C_NO_OID_SET;
}
}
return dst;
}
return src;
}
static uint32_t mag_context_loop(uint32_t *min,
request_rec *req,
struct mag_config *cfg,
gss_cred_id_t init_cred,
gss_cred_id_t accept_cred,
gss_OID mech_type,
uint32_t req_lifetime,
gss_name_t *client,
uint32_t *lifetime,
gss_cred_id_t *delegated_cred)
{
gss_ctx_id_t init_ctx = GSS_C_NO_CONTEXT;
gss_ctx_id_t accept_ctx = GSS_C_NO_CONTEXT;
gss_buffer_desc init_token = GSS_C_EMPTY_BUFFER;
gss_buffer_desc accept_token = GSS_C_EMPTY_BUFFER;
gss_name_t accept_name = GSS_C_NO_NAME;
uint32_t maj, tmin;
maj = gss_inquire_cred_by_mech(min, accept_cred, mech_type, &accept_name,
NULL, NULL, NULL);
if (GSS_ERROR(maj)) {
mag_post_error(req, cfg, MAG_GSS_ERR, maj, *min,
"gss_inquired_cred_by_mech() failed");
return maj;
}
do {
/* output and input are inverted here, this is intentional */
maj = gss_init_sec_context(min, init_cred, &init_ctx,
accept_name, mech_type, GSS_C_DELEG_FLAG,
req_lifetime, GSS_C_NO_CHANNEL_BINDINGS,
&accept_token, NULL, &init_token, NULL,
NULL);
if (GSS_ERROR(maj)) {
mag_post_error(req, cfg, MAG_GSS_ERR, maj, *min,
"gss_init_sec_context()");
goto done;
}
gss_release_buffer(&tmin, &accept_token);
maj = gss_accept_sec_context(min, &accept_ctx, accept_cred,
&init_token, GSS_C_NO_CHANNEL_BINDINGS,
client, NULL, &accept_token, NULL,
lifetime, delegated_cred);
if (GSS_ERROR(maj)) {
mag_post_error(req, cfg, MAG_GSS_ERR, maj, *min,
"gss_accept_sec_context()");
goto done;
}
gss_release_buffer(&tmin, &init_token);
} while (maj == GSS_S_CONTINUE_NEEDED);
done:
gss_release_name(&tmin, &accept_name);
gss_release_buffer(&tmin, &init_token);
gss_release_buffer(&tmin, &accept_token);
gss_delete_sec_context(&tmin, &init_ctx, GSS_C_NO_BUFFER);
gss_delete_sec_context(&tmin, &accept_ctx, GSS_C_NO_BUFFER);
return maj;
}
static int mag_complete(struct mag_req_cfg *req_cfg, struct mag_conn *mc,
gss_name_t client, gss_OID mech_type,
uint32_t vtime, gss_cred_id_t delegated_cred);
static int mag_auth_basic(struct mag_req_cfg *req_cfg, struct mag_conn *mc,
gss_buffer_desc ba_user, gss_buffer_desc ba_pwd)
{
struct mag_config *cfg = req_cfg->cfg;
request_rec *req = req_cfg->req;
const char *user_ccache = NULL;
const char *orig_ccache = NULL;
long long unsigned int rndname;
apr_status_t rs;
gss_name_t user = GSS_C_NO_NAME;
gss_cred_id_t user_cred = GSS_C_NO_CREDENTIAL;
gss_cred_id_t server_cred = GSS_C_NO_CREDENTIAL;
gss_OID_set allowed_mechs;
gss_OID_set filtered_mechs;
gss_OID_set actual_mechs = GSS_C_NO_OID_SET;
gss_cred_id_t delegated_cred = GSS_C_NO_CREDENTIAL;
gss_name_t client = GSS_C_NO_NAME;
uint32_t vtime;
uint32_t maj, min;
int present = 0;
int ret = HTTP_UNAUTHORIZED;
maj = gss_import_name(&min, &ba_user, GSS_C_NT_USER_NAME, &user);
if (GSS_ERROR(maj)) {
mag_post_error(req, cfg, MAG_GSS_ERR, maj, min,
"In Basic Auth: gss_import_name() failed");
goto done;
}
if (cfg->basic_mechs) {
allowed_mechs = cfg->basic_mechs;
} else if (cfg->allowed_mechs) {
allowed_mechs = cfg->allowed_mechs;
} else {
struct mag_server_config *scfg;
/* Try to fetch the default set if not explicitly configured,
* We need to do this because gss_acquire_cred_with_password()
* is currently limited to acquire creds for a single "default"
* mechanism if no desired mechanisms are passed in. This causes
* authentication to fail for secondary mechanisms as no user
* credentials are generated for those. */
scfg = ap_get_module_config(req->server->module_config,
&auth_gssapi_module);
/* In the worst case scenario default_mechs equals to GSS_C_NO_OID_SET.
* This generally causes only the krb5 mechanism to be tried due
* to implementation constraints, but may change in future. */
allowed_mechs = scfg->default_mechs;
}
/* Remove Spnego if present, or we'd repeat failed authentiations
* multiple times, one within Spnego and then again with an explicit
* mechanism. We would normally just force Spnego and use
* gss_set_neg_mechs, but due to the way we source the server name
* and the fact MIT up to 1.14 at least does no handle union names,
* we can't provide spnego with a server name that can be used by
* multiple mechanisms, causing any but the first mechanism to fail.
* Also remove unwanted krb mechs, or AS requests will be repeated
* multiple times uselessly.
*/
filtered_mechs = mag_filter_unwanted_mechs(allowed_mechs);
if (filtered_mechs == allowed_mechs) {
/* in case filtered_mechs was not allocated here don't free it */
filtered_mechs = GSS_C_NO_OID_SET;
} else if (filtered_mechs == GSS_C_NO_OID_SET) {
mag_post_error(req, cfg, MAG_INTERNAL, 0, 0,
"Fatal failure while filtering mechs, aborting");
goto done;
} else {
/* use the filtered list */
allowed_mechs = filtered_mechs;
}
/* If we are using the krb5 mechanism make sure to set a per thread
* memory ccache so that there can't be interferences between threads.
* Also make sure we have new cache so no cached results end up being
* used. Some implementations of gss_acquire_cred_with_password() do
* not reacquire creds if cached ones are around, failing to check
* again for the password. */
maj = gss_test_oid_set_member(&min, discard_const(gss_mech_krb5),
allowed_mechs, &present);
if (GSS_ERROR(maj)) {
mag_post_error(req, cfg, MAG_GSS_ERR, maj, min,
"In Basic Auth: gss_test_oid_set_member() failed");
goto done;
}
if (present) {
rs = apr_generate_random_bytes((unsigned char *)(&rndname),
sizeof(long long unsigned int));
if (rs != APR_SUCCESS) {
mag_post_error(req, cfg, MAG_INTERNAL, 0, 0,
"Failed to generate random ccache name");
goto done;
}
user_ccache = apr_psprintf(req->pool, "MEMORY:user_%qu", rndname);
maj = gss_krb5_ccache_name(&min, user_ccache, &orig_ccache);
if (GSS_ERROR(maj)) {
mag_post_error(req, cfg, MAG_GSS_ERR, maj, min,
"In Basic Auth: gss_krb5_ccache_name() failed");
goto done;
}
}
maj = gss_acquire_cred_with_password(&min, user, &ba_pwd,
cfg->basic_timeout,
allowed_mechs,
GSS_C_INITIATE,
&user_cred, &actual_mechs, NULL);
if (GSS_ERROR(maj)) {
mag_post_error(req, cfg, MAG_GSS_ERR, maj, min,
"In Basic Auth: gss_acquire_cred_with_password() "
"failed");
goto done;
}
/* must acquire creds based on the actual mechs we want to try */
if (!mag_acquire_creds(req, cfg, actual_mechs,
GSS_C_ACCEPT, &server_cred, NULL)) {
goto done;
}
for (int i = 0; i < actual_mechs->count; i++) {
maj = mag_context_loop(&min, req, cfg, user_cred, server_cred,
&actual_mechs->elements[i], cfg->basic_timeout,
&client, &vtime, &delegated_cred);
if (maj == GSS_S_COMPLETE) {
ret = mag_complete(req_cfg, mc, client, &actual_mechs->elements[i],
vtime, delegated_cred);
if (ret == OK) {
mag_basic_cache(req_cfg, mc, ba_user, ba_pwd);
}
break;
}
}
done:
gss_release_cred(&min, &delegated_cred);
gss_release_name(&min, &client);
gss_release_cred(&min, &server_cred);
gss_release_name(&min, &user);
gss_release_cred(&min, &user_cred);
gss_release_oid_set(&min, &actual_mechs);
gss_release_oid_set(&min, &filtered_mechs);
if (user_ccache != NULL) {
maj = gss_krb5_ccache_name(&min, orig_ccache, NULL);
if (maj != GSS_S_COMPLETE) {
ap_log_rerror(APLOG_MARK, APLOG_WARNING, 0, req,
"Failed to restore per-thread ccache, %s",
mag_error(req->pool, "gss_krb5_ccache_name() "
"failed", maj, min));
}
}
return ret;
}
#define OPTION_WARNING "Warning: %s is set but %s = %s is missing!"
void mag_verify_config(request_rec *req, struct mag_config *cfg)
{
/* we check only once */
if (cfg->verified) return;
#ifdef HAVE_CRED_STORE
/* Check if cred store config is consistent with use_s4u2proxy.
* Although not strictly required it is generally advisable to
* set keytab, client_keytab, and ccache in the cred_store when
* use_s4u2proxy is set, this is to avoid easy mistakes that are
* very difficult to diagnose */
if (cfg->use_s4u2proxy) {
bool has_keytab = false;
bool has_client_keytab = false;
bool has_ccache = false;
if (cfg->cred_store) {
for (int i = 0; i < cfg->cred_store->count; i++) {
const char *key = cfg->cred_store->elements[i].key;
if (strcmp(key, "keytab") == 0) {
has_keytab = true;
} else if (strcmp(key, "client_keytab") == 0) {
has_client_keytab = true;
} else if (strcmp(key, "ccache") == 0) {
has_ccache = true;
}
}
}
if (!has_keytab) {
ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, req,
OPTION_WARNING, "GssapiUseS4U2Proxy",
"GssapiCredStore", "keytab");
}
if (!has_client_keytab) {
ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, req,
OPTION_WARNING, "GssapiUseS4U2Proxy",
"GssapiCredStore", "client_keytab");
}
if (!has_ccache) {
ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, req,
OPTION_WARNING, "GssapiUseS4U2Proxy",
"GssapiCredStore", "ccache");
}
}
#endif
cfg->verified = true;
}
struct mag_req_cfg *mag_init_cfg(request_rec *req)
{
struct mag_server_config *scfg;
struct mag_req_cfg *req_cfg = apr_pcalloc(req->pool,
sizeof(struct mag_req_cfg));
req_cfg->req = req;
req_cfg->cfg = ap_get_module_config(req->per_dir_config,
&auth_gssapi_module);
mag_verify_config(req, req_cfg->cfg);
scfg = ap_get_module_config(req->server->module_config,
&auth_gssapi_module);
if (req_cfg->cfg->allowed_mechs) {
req_cfg->desired_mechs = req_cfg->cfg->allowed_mechs;
} else {
/* Use the default set if not explicitly configured */
req_cfg->desired_mechs = scfg->default_mechs;
}
if (req_cfg->cfg->mag_skey) {
req_cfg->mag_skey = req_cfg->cfg->mag_skey;
} else {
/* Use server random key if not explicitly configured */
req_cfg->mag_skey = scfg->mag_skey;
}
if (req->proxyreq == PROXYREQ_PROXY) {
req_cfg->req_proto = "Proxy-Authorization";
req_cfg->rep_proto = "Proxy-Authenticate";
} else {
req_cfg->req_proto = "Authorization";
req_cfg->rep_proto = "WWW-Authenticate";
req_cfg->use_sessions = req_cfg->cfg->use_sessions;
req_cfg->send_persist = req_cfg->cfg->send_persist;
}
return req_cfg;
}
#ifdef HAVE_CRED_STORE
static bool use_s4u2proxy(struct mag_req_cfg *req_cfg) {
if (req_cfg->cfg->use_s4u2proxy) {
if (req_cfg->cfg->deleg_ccache_dir != NULL) {
return true;
} else {
ap_log_rerror(APLOG_MARK, APLOG_ERR, 0, req_cfg->req,
"S4U2 Proxy requested but GssapiDelegCcacheDir "
"is not set. Constrained delegation disabled!");
}
}
return false;
}
static apr_status_t mag_s4u2self(request_rec *req)
{
apr_status_t ret = DECLINED;
const char *type;
struct mag_config *cfg;
struct mag_req_cfg *req_cfg;
gss_OID mech_type = discard_const(gss_mech_krb5);
gss_OID_set_desc gss_mech_krb5_set = { 1, mech_type };
gss_buffer_desc user_name = GSS_C_EMPTY_BUFFER;
gss_cred_id_t user_cred = GSS_C_NO_CREDENTIAL;
gss_name_t user = GSS_C_NO_NAME;
gss_name_t client = GSS_C_NO_NAME;
gss_cred_id_t server_cred = GSS_C_NO_CREDENTIAL;
gss_cred_id_t delegated_cred = GSS_C_NO_CREDENTIAL;
struct mag_conn *mc = NULL;
uint32_t vtime;
uint32_t maj, min;
req_cfg = mag_init_cfg(req);
cfg = req_cfg->cfg;
if (!cfg->s4u2self) {
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, req,
"GSSapiImpersonate not On, skipping impersonation.");
return DECLINED;
}
type = ap_auth_type(req);
if (type && (strcasecmp(type, "GSSAPI") == 0)) {
/* do not try to impersonate if GSSAPI is handling real auth */
return DECLINED;
}
if (!req->user) {
ap_log_rerror(APLOG_MARK, APLOG_INFO, 0, req,
"Authentication user not found, "
"skipping impersonation.");
return DECLINED;
}
ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, req,
"Using user %s for impersonation.", req->user);
if (!mag_acquire_creds(req, cfg, &gss_mech_krb5_set,
GSS_C_BOTH, &server_cred, NULL)) {
goto done;
}
user_name.value = req->user;
user_name.length = strlen(user_name.value);
maj = gss_import_name(&min, &user_name, GSS_C_NT_USER_NAME, &user);
if (GSS_ERROR(maj)) {
mag_post_error(req, cfg, MAG_GSS_ERR, maj, min,
"In S4U2Self: gss_import_name()");
goto done;
}
maj = gss_acquire_cred_impersonate_name(&min, server_cred, user,
GSS_C_INDEFINITE,
&gss_mech_krb5_set,
GSS_C_INITIATE, &user_cred,
NULL, NULL);
if (GSS_ERROR(maj)) {
mag_post_error(req, cfg, MAG_GSS_ERR, maj, min,
"In S4U2Self: gss_acquire_cred_impersonate_name()");
goto done;
}
/* the following exchange is needed to decrypt the ticket and get named
* attributes as well as check if the ticket is forwardable when
* delegated credentials are requested */
maj = mag_context_loop(&min, req, cfg, user_cred, server_cred,
discard_const(gss_mech_krb5), GSS_C_INDEFINITE,
&client, &vtime, &delegated_cred);
if (GSS_ERROR(maj))
goto done;
if (cfg->deleg_ccache_dir && delegated_cred == GSS_C_NO_CREDENTIAL) {
mag_post_error(req, cfg, MAG_INTERNAL, 0, 0,
"Failed to obtain delegated credentials, "
"does service have +ok_to_auth_as_delegate?");
goto done;
}
mc = mag_new_conn_ctx(req->pool);
mc->auth_type = AUTH_TYPE_IMPERSONATE;
ret = mag_complete(req_cfg, mc, client, mech_type, vtime, delegated_cred);
if (ret != OK) ret = DECLINED;
done:
gss_release_cred(&min, &user_cred);
gss_release_name(&min, &user);
gss_release_name(&min, &client);
gss_release_cred(&min, &server_cred);
gss_release_cred(&min, &delegated_cred);
return ret;
}
#endif
static apr_status_t mag_oid_set_destroy(void *ptr)
{
uint32_t min;
gss_OID_set set = (gss_OID_set)ptr;
(void)gss_release_oid_set(&min, &set);
return APR_SUCCESS;
}
static gss_OID_set mag_get_negotiate_mechs(apr_pool_t *p, gss_OID_set desired)
{
gss_OID spnego_oid = discard_const(&gss_mech_spnego);
uint32_t maj, min;
int present = 0;
maj = gss_test_oid_set_member(&min, spnego_oid, desired, &present);
if (maj != GSS_S_COMPLETE) {
return GSS_C_NO_OID_SET;
}
if (present) {
return desired;
} else {
gss_OID_set set;
maj = gss_create_empty_oid_set(&min, &set);
if (maj != GSS_S_COMPLETE) {
return GSS_C_NO_OID_SET;
}
apr_pool_cleanup_register(p, (void *)set,
mag_oid_set_destroy,
apr_pool_cleanup_null);
maj = gss_add_oid_set_member(&min, spnego_oid, &set);
if (maj != GSS_S_COMPLETE) {
return GSS_C_NO_OID_SET;
}
for (int i = 0; i < desired->count; i++) {
maj = gss_add_oid_set_member(&min, &desired->elements[i], &set);
if (maj != GSS_S_COMPLETE) {
return GSS_C_NO_OID_SET;
}
}
return set;
}
}
static int mag_auth(request_rec *req)
{
const char *type;
int auth_type = -1;
struct mag_req_cfg *req_cfg;
struct mag_config *cfg;
const char *auth_header;
char *auth_header_type;
int ret = HTTP_UNAUTHORIZED;
gss_ctx_id_t ctx = GSS_C_NO_CONTEXT;
gss_ctx_id_t *pctx;
gss_buffer_desc input = GSS_C_EMPTY_BUFFER;
gss_buffer_desc output = GSS_C_EMPTY_BUFFER;
gss_buffer_desc ba_user;
gss_buffer_desc ba_pwd;
gss_name_t client = GSS_C_NO_NAME;
gss_cred_id_t acquired_cred = GSS_C_NO_CREDENTIAL;
gss_cred_id_t delegated_cred = GSS_C_NO_CREDENTIAL;
gss_cred_usage_t cred_usage = GSS_C_ACCEPT;
uint32_t vtime;
uint32_t maj, min;
char *reply;
size_t replen;
gss_OID mech_type = GSS_C_NO_OID;
gss_OID_set desired_mechs = GSS_C_NO_OID_SET;
struct mag_conn *mc = NULL;
int i;
bool send_nego_header = true;
type = ap_auth_type(req);
if ((type == NULL) || (strcasecmp(type, "GSSAPI") != 0)) {
return DECLINED;
}
req_cfg = mag_init_cfg(req);
cfg = req_cfg->cfg;
if ((req_cfg->desired_mechs == GSS_C_NO_OID_SET) ||
(req_cfg->desired_mechs->count == 0)) {
mag_post_error(req, cfg, MAG_INTERNAL, 0, 0,
"List of desired mechs is missing or empty, "