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#include "php_snuffleupagus.h"
#define LOG_FEATURE "wrappers_whitelist"
static bool wrapper_is_whitelisted(const zend_string *const zs) {
const sp_list_node *list = SPCFG(wrapper).whitelist;
if (!zs) {
return false; // LCOV_EXCL_LINE
}
while (list) {
if (zend_string_equals_ci(zs, (const zend_string *)list->data)) {
return true;
}
list = list->next;
}
return false;
}
static bool sp_php_stream_is_filtered(void) {
const sp_list_node *list = SPCFG(wrapper).php_stream_allowlist;
return list != NULL;
}
static bool sp_php_stream_is_whitelisted(const char *const kind) {
const sp_list_node *list = SPCFG(wrapper).php_stream_allowlist;
while (list) {
if (!strcasecmp(kind, ZSTR_VAL((const zend_string *)list->data))) {
return true;
}
list = list->next;
}
return false;
}
/*
* Adopted from
* https://github.com/php/php-src/blob/8896bd3200892000d8aaa01595d6c64b926a26f7/ext/standard/php_fopen_wrapper.c#L176
*/
static php_stream * sp_php_stream_url_wrap_php(php_stream_wrapper *wrapper,
const char *path, const char *mode,
int options, zend_string **opened_path,
php_stream_context *context STREAMS_DC) {
if (!strncasecmp(path, "php://", 6)) {
path += 6;
}
if (!strncasecmp(path, "temp", 4)) {
if (!sp_php_stream_is_whitelisted("temp")) {
sp_log_warn(LOG_FEATURE, "Call to not allowed php stream type \"temp\" dropped");
return NULL;
}
} else if (!strcasecmp(path, "memory")) {
if (!sp_php_stream_is_whitelisted("memory")) {
sp_log_warn(LOG_FEATURE, "Call to not allowed php stream type \"memory\" dropped");
return NULL;
}
} else if (!strcasecmp(path, "output")) {
if (!sp_php_stream_is_whitelisted("output")) {
sp_log_warn(LOG_FEATURE, "Call to not allowed php stream type \"output\" dropped");
return NULL;
}
} else if (!strcasecmp(path, "input")) {
if (!sp_php_stream_is_whitelisted("input")) {
sp_log_warn(LOG_FEATURE, "Call to not allowed php stream type \"input\" dropped");
return NULL;
}
} else if (!strcasecmp(path, "stdin")) {
if (!sp_php_stream_is_whitelisted("stdin")) {
sp_log_warn(LOG_FEATURE, "Call to not allowed php stream type \"stdin\" dropped");
return NULL;
}
} else if (!strcasecmp(path, "stdout")) {
if (!sp_php_stream_is_whitelisted("stdout")) {
sp_log_warn(LOG_FEATURE, "Call to not allowed php stream type \"stdout\" dropped");
return NULL;
}
} else if (!strcasecmp(path, "stderr")) {
if (!sp_php_stream_is_whitelisted("stderr")) {
sp_log_warn(LOG_FEATURE, "Call to not allowed php stream type \"stderr\" dropped");
return NULL;
}
} else if (!strncasecmp(path, "fd/", 3)) {
if (!sp_php_stream_is_whitelisted("fd")) {
sp_log_warn(LOG_FEATURE, "Call to not allowed php stream type \"fd\" dropped");
return NULL;
}
} else if (!strncasecmp(path, "filter/", 7)) {
if (!sp_php_stream_is_whitelisted("filter")) {
sp_log_warn(LOG_FEATURE, "Call to not allowed php stream type \"filter\" dropped");
return NULL;
}
} else {
sp_log_warn(LOG_FEATURE, "Call to unknown php stream type dropped");
return NULL;
}
extern PHPAPI const php_stream_wrapper php_stream_php_wrapper;
return php_stream_php_wrapper.wops->stream_opener(wrapper, path, mode, options, opened_path, context STREAMS_DC);
}
/*
* Adopted from
* https://github.com/php/php-src/blob/8896bd3200892000d8aaa01595d6c64b926a26f7/ext/standard/php_fopen_wrapper.c#L428-L446
*/
static const php_stream_wrapper_ops sp_php_stdio_wops = {
sp_php_stream_url_wrap_php,
NULL, /* close */
NULL, /* fstat */
NULL, /* stat */
NULL, /* opendir */
"PHP",
NULL, /* unlink */
NULL, /* rename */
NULL, /* mkdir */
NULL, /* rmdir */
NULL
};
static const php_stream_wrapper sp_php_stream_php_wrapper = {
&sp_php_stdio_wops,
NULL,
0, /* is_url */
};
static void sp_reregister_php_wrapper(void) {
if (!sp_php_stream_is_filtered()) {
return;
}
if (php_unregister_url_stream_wrapper("php") != SUCCESS) {
sp_log_warn(LOG_FEATURE, "Failed to unregister stream wrapper \"php\"");
return;
}
if (php_register_url_stream_wrapper("php", &sp_php_stream_php_wrapper) != SUCCESS) {
sp_log_warn(LOG_FEATURE, "Failed to register custom stream wrapper \"php\"");
}
sp_log_debug(LOG_FEATURE, "Stream \"php\" successfully re-registered");
}
void sp_disable_wrapper() {
HashTable *orig = php_stream_get_url_stream_wrappers_hash();
HashTable *orig_complete = pemalloc(sizeof(HashTable), 1);
zval *zv;
zend_string *zs;
// Copy the original hashtable into a temporary one, as I'm not sure about
// the behaviour of ZEND_HASH_FOREACH when element are removed from the
// hashtable used in the loop.
zend_hash_init(orig_complete, zend_hash_num_elements(orig), NULL, NULL, 1);
zend_hash_copy(orig_complete, orig, NULL);
zend_hash_clean(orig);
ZEND_HASH_FOREACH_STR_KEY_VAL(orig_complete, zs, zv) {
if (wrapper_is_whitelisted(zs)) {
zend_hash_add(orig, zs, zv);
}
}
ZEND_HASH_FOREACH_END();
zend_hash_destroy(orig_complete);
pefree(orig_complete, 1);
SPCFG(wrapper).num_wrapper = zend_hash_num_elements(orig);
}
PHP_FUNCTION(sp_stream_wrapper_register) {
zif_handler orig_handler;
zend_string *protocol_name = NULL;
zval *params = NULL;
uint32_t param_count = 0;
zend_parse_parameters_ex(ZEND_PARSE_PARAMS_QUIET, ZEND_NUM_ARGS(), "S*", &protocol_name, ¶ms, ¶m_count);
// ignore proper arguments here and just let the original handler deal with it
if (!protocol_name || wrapper_is_whitelisted(protocol_name)) {
// reject manual loading of "php" wrapper
if (!strcasecmp(ZSTR_VAL(protocol_name), "php") && sp_php_stream_is_filtered()) {
return;
}
orig_handler = zend_hash_str_find_ptr(SPG(sp_internal_functions_hook), ZEND_STRL("stream_wrapper_register"));
orig_handler(INTERNAL_FUNCTION_PARAM_PASSTHRU);
}
}
int hook_stream_wrappers() {
TSRMLS_FETCH();
HOOK_FUNCTION("stream_wrapper_register", sp_internal_functions_hook,
PHP_FN(sp_stream_wrapper_register));
sp_reregister_php_wrapper();
return SUCCESS;
}
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