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#include "php_snuffleupagus.h"
#include <errno.h>
#include <string.h>
ZEND_DECLARE_MODULE_GLOBALS(snuffleupagus)
static void (*orig_execute_ex)(zend_execute_data *execute_data);
static void (*orig_zend_execute_internal)(zend_execute_data *execute_data,
zval *return_value);
static int (*orig_zend_stream_open)(const char *filename,
zend_file_handle *handle);
// FIXME handle symlink
ZEND_COLD static inline void terminate_if_writable(const char *filename) {
if (0 == access(filename, W_OK)) {
if (true == SNUFFLEUPAGUS_G(config).config_readonly_exec->simulation) {
sp_log_msg("readonly_exec", SP_LOG_SIMULATION,
"Attempted execution of a writable file (%s).", filename);
} else {
sp_log_msg("readonly_exec", SP_LOG_DROP,
"Attempted execution of a writable file (%s).", filename);
sp_terminate();
}
} else {
if (EACCES != errno) {
sp_log_err("Writable execution", "Error while accessing %s: %s", filename,
strerror(errno));
}
}
}
static void is_builtin_matching(const char *restrict const filename,
const char *restrict const function_name,
const char *restrict const param_name,
const sp_list_node *config) {
if (!config || !config->data) {
return;
}
if (true == should_disable(EG(current_execute_data), function_name, filename,
param_name)) {
sp_terminate();
}
}
static void ZEND_HOT
is_in_eval_and_whitelisted(const zend_execute_data *execute_data) {
if (EXPECTED(0 == SNUFFLEUPAGUS_G(in_eval))) {
return;
}
if (EXPECTED(NULL == SNUFFLEUPAGUS_G(config).config_eval->whitelist->data)) {
return;
}
if (zend_is_executing() && !EG(current_execute_data)->func) {
return;
}
if (!(execute_data->func->common.function_name)) {
return;
}
char const *const current_function = ZSTR_VAL(EX(func)->common.function_name);
if (EXPECTED(NULL != current_function)) {
if (false == check_is_in_eval_whitelist(current_function)) {
sp_log_msg(
"Eval_whitelist", SP_LOG_DROP,
"The function '%s' isn't in the eval whitelist, dropping its call.",
current_function);
sp_terminate();
}
}
}
/* This function gets the filename in which `eval()` is called from,
* since it looks like "foo.php(1) : eval()'d code", so we're starting
* from the end of the string until the second closing parenthesis. */
char *get_eval_filename(const char *filename) {
size_t i = strlen(filename);
int count = 0;
char *clean_filename = estrdup(filename);
while (i--) {
if (clean_filename[i] == '(') {
if (count == 1) {
clean_filename[i] = '\0';
break;
}
count++;
}
}
return clean_filename;
}
static void sp_execute_ex(zend_execute_data *execute_data) {
is_in_eval_and_whitelisted(execute_data);
if (true == should_disable(execute_data, NULL, NULL, NULL)) {
sp_terminate();
}
if (EX(func)->op_array.type == ZEND_EVAL_CODE) {
SNUFFLEUPAGUS_G(in_eval)++;
const sp_list_node *config =
SNUFFLEUPAGUS_G(config).config_disabled_constructs->construct_eval;
char *filename = get_eval_filename((char *)zend_get_executed_filename());
is_builtin_matching(filename, "eval", NULL, config);
efree(filename);
}
if (NULL != EX(func)->op_array.filename) {
if (true == SNUFFLEUPAGUS_G(config).config_readonly_exec->enable) {
terminate_if_writable(ZSTR_VAL(EX(func)->op_array.filename));
}
}
orig_execute_ex(execute_data);
if (true == should_drop_on_ret(EX(return_value), execute_data)) {
sp_terminate();
}
if (ZEND_EVAL_CODE == EX(func)->op_array.type) {
SNUFFLEUPAGUS_G(in_eval)--;
}
}
static void sp_zend_execute_internal(INTERNAL_FUNCTION_PARAMETERS) {
is_in_eval_and_whitelisted(execute_data);
EX(func)->internal_function.handler(INTERNAL_FUNCTION_PARAM_PASSTHRU);
if (UNEXPECTED(NULL != orig_zend_execute_internal)) {
orig_zend_execute_internal(INTERNAL_FUNCTION_PARAM_PASSTHRU);
}
}
static int sp_stream_open(const char *filename, zend_file_handle *handle) {
zend_execute_data const *const data = EG(current_execute_data);
if ((NULL == data) || (NULL == data->opline) ||
(data->func->type != ZEND_USER_FUNCTION)) {
goto end;
}
switch (data->opline->opcode) {
case ZEND_INCLUDE_OR_EVAL:
if (true == SNUFFLEUPAGUS_G(config).config_readonly_exec->enable) {
terminate_if_writable(filename);
}
const sp_list_node *config =
SNUFFLEUPAGUS_G(config).config_disabled_constructs->construct_include;
switch (data->opline->extended_value) {
case ZEND_INCLUDE:
is_builtin_matching(filename, "include", "inclusion path", config);
break;
case ZEND_REQUIRE:
is_builtin_matching(filename, "require", "inclusion path", config);
break;
case ZEND_REQUIRE_ONCE:
is_builtin_matching(filename, "require_once", "inclusion path",
config);
break;
case ZEND_INCLUDE_ONCE:
is_builtin_matching(filename, "include_once", "inclusion path",
config);
break;
EMPTY_SWITCH_DEFAULT_CASE();
}
}
end:
return orig_zend_stream_open(filename, handle);
}
int hook_execute(void) {
TSRMLS_FETCH();
/* zend_execute_ex is used for "user" function calls */
orig_execute_ex = zend_execute_ex;
zend_execute_ex = sp_execute_ex;
/* zend_execute_internal is used for "builtin" functions calls */
orig_zend_execute_internal = zend_execute_internal;
zend_execute_internal = sp_zend_execute_internal;
/* zend_stream_open_function is used for include-related stuff */
orig_zend_stream_open = zend_stream_open_function;
zend_stream_open_function = sp_stream_open;
return SUCCESS;
}
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