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#include "first.h"
/* mod_authn_pam
*
* FUTURE POTENTIAL PERFORMANCE ENHANCEMENTS:
* - database response is not cached
* TODO: db response caching (for limited time) to reduce load on db
* (only cache successful logins to prevent cache bloat?)
* (or limit number of entries (size) of cache)
* (maybe have negative cache (limited size) of names not found in database)
* - database query is synchronous and blocks waiting for response
*/
#include <security/pam_appl.h>
#include "base.h"
#include "http_auth.h"
#include "log.h"
#include "plugin.h"
#include <stdlib.h>
#include <string.h>
typedef struct {
array *opts;
const char *service;
} plugin_config;
typedef struct {
PLUGIN_DATA;
plugin_config **config_storage;
plugin_config conf;
} plugin_data;
static handler_t mod_authn_pam_basic(server *srv, connection *con, void *p_d, const http_auth_require_t *require, const buffer *username, const char *pw);
INIT_FUNC(mod_authn_pam_init) {
static http_auth_backend_t http_auth_backend_pam =
{ "pam", mod_authn_pam_basic, NULL, NULL };
plugin_data *p = calloc(1, sizeof(*p));
/* register http_auth_backend_pam */
http_auth_backend_pam.p_d = p;
http_auth_backend_set(&http_auth_backend_pam);
return p;
}
FREE_FUNC(mod_authn_pam_free) {
plugin_data *p = p_d;
if (!p) return HANDLER_GO_ON;
if (p->config_storage) {
for (size_t i = 0; i < srv->config_context->used; ++i) {
plugin_config *s = p->config_storage[i];
if (NULL == s) continue;
array_free(s->opts);
free(s);
}
free(p->config_storage);
}
free(p);
UNUSED(srv);
return HANDLER_GO_ON;
}
SETDEFAULTS_FUNC(mod_authn_pam_set_defaults) {
plugin_data *p = p_d;
config_values_t cv[] = {
{ "auth.backend.pam.opts", NULL, T_CONFIG_ARRAY, T_CONFIG_SCOPE_CONNECTION },
{ NULL, NULL, T_CONFIG_UNSET, T_CONFIG_SCOPE_UNSET }
};
p->config_storage = calloc(1, srv->config_context->used * sizeof(plugin_config *));
for (size_t i = 0; i < srv->config_context->used; ++i) {
data_config const *config = (data_config const*)srv->config_context->data[i];
data_string *ds;
plugin_config *s = calloc(1, sizeof(plugin_config));
s->opts = array_init();
cv[0].destination = s->opts;
p->config_storage[i] = s;
if (0 != config_insert_values_global(srv, config->value, cv, i == 0 ? T_CONFIG_SCOPE_SERVER : T_CONFIG_SCOPE_CONNECTION)) {
return HANDLER_ERROR;
}
if (0 == s->opts->used) continue;
ds = (data_string *)
array_get_element_klen(s->opts, CONST_STR_LEN("service"));
s->service = (NULL != ds) ? ds->value->ptr : "http";
}
if (p->config_storage[0]->service == NULL)
p->config_storage[0]->service = "http";
return HANDLER_GO_ON;
}
#define PATCH(x) \
p->conf.x = s->x;
static int mod_authn_pam_patch_connection(server *srv, connection *con, plugin_data *p) {
plugin_config *s = p->config_storage[0];
PATCH(service);
/* skip the first, the global context */
for (size_t i = 1; i < srv->config_context->used; ++i) {
data_config *dc = (data_config *)srv->config_context->data[i];
/* condition didn't match */
if (!config_check_cond(srv, con, dc)) continue;
/* merge config */
s = p->config_storage[i];
for (size_t j = 0; j < dc->value->used; ++j) {
data_unset *du = dc->value->data[j];
if (buffer_is_equal_string(du->key, CONST_STR_LEN("auth.backend.pam.opts"))) {
PATCH(service);
}
}
}
return 0;
}
#undef PATCH
static int mod_authn_pam_fn_conv(int num_msg, const struct pam_message **msg, struct pam_response **resp, void *appdata_ptr) {
const char * const pw = (char *)appdata_ptr;
struct pam_response * const pr = *resp =
(struct pam_response *)malloc(num_msg * sizeof(struct pam_response));
for (int i = 0; i < num_msg; ++i) {
const int style = msg[i]->msg_style;
pr[i].resp_retcode = 0;
pr[i].resp = (style==PAM_PROMPT_ECHO_OFF || style==PAM_PROMPT_ECHO_ON)
? strdup(pw)
: NULL;
}
return PAM_SUCCESS;
}
static handler_t mod_authn_pam_query(server *srv, connection *con, void *p_d, const buffer *username, const char *realm, const char *pw) {
plugin_data *p = (plugin_data *)p_d;
pam_handle_t *pamh = NULL;
struct pam_conv conv = { mod_authn_pam_fn_conv, NULL };
const int flags = PAM_SILENT | PAM_DISALLOW_NULL_AUTHTOK;
int rc;
UNUSED(realm);
*(const char **)&conv.appdata_ptr = pw; /*(cast away const)*/
mod_authn_pam_patch_connection(srv, con, p);
rc = pam_start(p->conf.service, username->ptr, &conv, &pamh);
if (PAM_SUCCESS != rc
|| PAM_SUCCESS !=(rc = pam_set_item(pamh,PAM_RHOST,con->dst_addr_buf->ptr))
|| PAM_SUCCESS !=(rc = pam_authenticate(pamh, flags))
|| PAM_SUCCESS !=(rc = pam_acct_mgmt(pamh, flags)))
log_error_write(srv, __FILE__, __LINE__, "ss",
"pam:", pam_strerror(pamh, rc));
pam_end(pamh, rc);
return (PAM_SUCCESS == rc) ? HANDLER_GO_ON : HANDLER_ERROR;
}
static handler_t mod_authn_pam_basic(server *srv, connection *con, void *p_d, const http_auth_require_t *require, const buffer *username, const char *pw) {
char *realm = require->realm->ptr;
handler_t rc = mod_authn_pam_query(srv, con, p_d, username, realm, pw);
if (HANDLER_GO_ON != rc) return rc;
return http_auth_match_rules(require, username->ptr, NULL, NULL)
? HANDLER_GO_ON /* access granted */
: HANDLER_ERROR;
}
int mod_authn_pam_plugin_init(plugin *p);
int mod_authn_pam_plugin_init(plugin *p) {
p->version = LIGHTTPD_VERSION_ID;
p->name = buffer_init_string("authn_pam");
p->data = NULL;
p->init = mod_authn_pam_init;
p->cleanup = mod_authn_pam_free;
p->set_defaults= mod_authn_pam_set_defaults;
return 0;
}
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