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This patch is based on http://kyberdigi.cz/projects/execdir/ but instead trying
to sanitize the exec command string inside PHP this job is handled by bash and
a special restricted PHP-mode which strips off all path informations.
This patch depends on:
- bash restricted php mode patch
https://manuel.mausz.at/coding/patches/php/bash-4.2-restricted-php.patch
No warranty!
diff -Naur a/ext/standard/exec.c b/ext/standard/exec.c
--- a/ext/standard/exec.c 2018-07-31 16:33:11.000000000 +0200
+++ b/ext/standard/exec.c 2018-08-03 18:54:50.069801829 +0200
@@ -99,21 +99,30 @@
char *buf;
size_t l = 0;
int pclose_return;
- char *b, *d=NULL;
+ char *cmd_p, *b, *d=NULL;
php_stream *stream;
size_t buflen, bufl = 0;
#if PHP_SIGCHILD
void (*sig_handler)() = NULL;
#endif
+ if (PG(exec_dir) && strlen(PG(exec_dir))) {
+ zend_string *cmd_esc = php_escape_shell_arg(cmd);
+ spprintf(&d, 0, "PATH=%s /bin/bash --php -rc %s", PG(exec_dir), ZSTR_VAL(cmd_esc));
+ zend_string_release(cmd_esc);
+ cmd_p = d;
+ } else {
+ cmd_p = cmd;
+ }
+
#if PHP_SIGCHILD
sig_handler = signal (SIGCHLD, SIG_DFL);
#endif
#ifdef PHP_WIN32
- fp = VCWD_POPEN(cmd, "rb");
+ fp = VCWD_POPEN(cmd_p, "rb");
#else
- fp = VCWD_POPEN(cmd, "r");
+ fp = VCWD_POPEN(cmd_p, "r");
#endif
if (!fp) {
php_error_docref(NULL, E_WARNING, "Unable to fork [%s]", cmd);
@@ -521,7 +530,7 @@
PHP_FUNCTION(shell_exec)
{
FILE *in;
- char *command;
+ char *command, *command_p;
size_t command_len;
zend_string *ret;
php_stream *stream;
@@ -530,14 +539,24 @@
Z_PARAM_STRING(command, command_len)
ZEND_PARSE_PARAMETERS_END();
+ if (PG(exec_dir) && strlen(PG(exec_dir))) {
+ zend_string *cmd_esc = php_escape_shell_arg(command);
+ spprintf(&command_p, 0, "PATH=%s /bin/bash --php -rc %s", PG(exec_dir), ZSTR_VAL(cmd_esc));
+ zend_string_release(cmd_esc);
+ } else {
+ command_p = estrdup(command);
+ }
+
#ifdef PHP_WIN32
- if ((in=VCWD_POPEN(command, "rt"))==NULL) {
+ if ((in=VCWD_POPEN(command_p, "rt"))==NULL) {
#else
- if ((in=VCWD_POPEN(command, "r"))==NULL) {
+ if ((in=VCWD_POPEN(command_p, "r"))==NULL) {
#endif
php_error_docref(NULL, E_WARNING, "Unable to execute '%s'", command);
+ efree(command_p);
RETURN_FALSE;
}
+ efree(command_p);
stream = php_stream_fopen_from_pipe(in, "rb");
ret = php_stream_copy_to_mem(stream, PHP_STREAM_COPY_ALL, 0);
diff -Naur a/ext/standard/file.c b/ext/standard/file.c
--- a/ext/standard/file.c 2018-07-31 16:33:09.000000000 +0200
+++ b/ext/standard/file.c 2018-08-03 18:54:50.070801819 +0200
@@ -950,7 +950,16 @@
}
#endif
- fp = VCWD_POPEN(command, posix_mode);
+ if (PG(exec_dir) && strlen(PG(exec_dir))) {
+ zend_string *cmd_esc = php_escape_shell_arg(command);
+ char *tmp;
+ spprintf(&tmp, 0, "PATH=%s /bin/bash --php -rc %s", PG(exec_dir), ZSTR_VAL(cmd_esc));
+ fp = VCWD_POPEN(tmp, posix_mode);
+ efree(tmp);
+ zend_string_release(cmd_esc);
+ } else {
+ fp = VCWD_POPEN(command, posix_mode);
+ }
if (!fp) {
php_error_docref2(NULL, command, posix_mode, E_WARNING, "%s", strerror(errno));
efree(posix_mode);
diff -Naur a/ext/standard/filestat.c b/ext/standard/filestat.c
--- a/ext/standard/filestat.c 2018-07-31 16:33:11.000000000 +0200
+++ b/ext/standard/filestat.c 2018-08-03 18:54:50.071801808 +0200
@@ -769,13 +769,14 @@
"size", "atime", "mtime", "ctime", "blksize", "blocks"
};
const char *local;
+ char local_safe[MAXPATHLEN];
php_stream_wrapper *wrapper;
if (!filename_length) {
RETURN_FALSE;
}
- if ((wrapper = php_stream_locate_url_wrapper(filename, &local, 0)) == &php_plain_files_wrapper && php_check_open_basedir(local)) {
+ if ((wrapper = php_stream_locate_url_wrapper(filename, &local, 0)) == &php_plain_files_wrapper && type != FS_IS_X && php_check_open_basedir(local)) {
RETURN_FALSE;
}
@@ -800,6 +801,19 @@
#endif
#ifdef X_OK
case FS_IS_X:
+ if (PG(exec_dir) && strlen(PG(exec_dir))) {
+ if (strstr(local, "..")) {
+ RETURN_FALSE;
+ } else {
+ char *b = strrchr(local, PHP_DIR_SEPARATOR);
+ if (b) {
+ snprintf(local_safe, MAXPATHLEN, "%s%s", PG(exec_dir), b);
+ } else {
+ snprintf(local_safe, MAXPATHLEN, "%s%c%s", PG(exec_dir), PHP_DIR_SEPARATOR, local);
+ }
+ local = (char *)&local_safe;
+ }
+ }
RETURN_BOOL(VCWD_ACCESS(local, X_OK) == 0);
break;
#endif
diff -Naur a/ext/standard/proc_open.c b/ext/standard/proc_open.c
--- a/ext/standard/proc_open.c 2018-07-31 16:33:11.000000000 +0200
+++ b/ext/standard/proc_open.c 2018-08-03 18:54:50.071801808 +0200
@@ -483,6 +483,15 @@
command_len = strlen(command);
+ zval envpath;
+ if (PG(exec_dir) && strlen(PG(exec_dir))) {
+ if (!environment || zend_hash_num_elements(Z_ARRVAL_P(environment)) == 0) {
+ array_init_size(&envpath, 1);
+ environment = &envpath;
+ }
+ add_assoc_string(environment, "PATH", PG(exec_dir));
+ }
+
if (environment) {
env = _php_array_to_envp(environment, is_persistent);
} else {
@@ -835,10 +844,14 @@
php_ignore_value(chdir(cwd));
}
- if (env.envarray) {
- execle("/bin/sh", "sh", "-c", command, NULL, env.envarray);
+ if (PG(exec_dir) && strlen(PG(exec_dir))) {
+ execle("/bin/bash", "bash", "--php", "-rc", command, NULL, env.envarray);
} else {
- execl("/bin/sh", "sh", "-c", command, NULL);
+ if (env.envarray) {
+ execle("/bin/sh", "sh", "-c", command, NULL, env.envarray);
+ } else {
+ execl("/bin/sh", "sh", "-c", command, NULL);
+ }
}
_exit(127);
diff -Naur a/main/main.c b/main/main.c
--- a/main/main.c 2018-07-31 16:33:06.000000000 +0200
+++ b/main/main.c 2018-08-03 18:58:34.802426791 +0200
@@ -797,6 +797,7 @@
STD_PHP_INI_ENTRY("syslog.facility", "LOG_USER", PHP_INI_SYSTEM, OnSetFacility, syslog_facility, php_core_globals, core_globals)
STD_PHP_INI_ENTRY("syslog.ident", "php", PHP_INI_SYSTEM, OnUpdateString, syslog_ident, php_core_globals, core_globals)
STD_PHP_INI_ENTRY("syslog.filter", "no-ctrl", PHP_INI_ALL, OnSetLogFilter, syslog_filter, php_core_globals, core_globals)
+ STD_PHP_INI_ENTRY("exec_dir", NULL, PHP_INI_SYSTEM, OnUpdateString, exec_dir, php_core_globals, core_globals)
PHP_INI_END()
/* }}} */
diff -Naur a/main/php_globals.h b/main/php_globals.h
--- a/main/php_globals.h 2018-07-31 16:33:06.000000000 +0200
+++ b/main/php_globals.h 2018-08-03 18:55:27.213409218 +0200
@@ -169,6 +169,8 @@
char *syslog_ident;
zend_bool have_called_openlog;
zend_long syslog_filter;
+
+ char *exec_dir;
};
diff -Naur a/php.ini-development b/php.ini-development
--- a/php.ini-development 2018-07-31 16:33:05.000000000 +0200
+++ b/php.ini-development 2018-08-03 18:54:50.074801776 +0200
@@ -303,6 +303,10 @@
; http://php.net/open-basedir
;open_basedir =
+; Only executables located in the exec_dir will be allowed to be executed
+; via the exec family of functions.
+exec_dir =
+
; This directive allows you to disable certain functions for security reasons.
; It receives a comma-delimited list of function names.
; http://php.net/disable-functions
diff -Naur a/php.ini-production b/php.ini-production
--- a/php.ini-production 2018-07-31 16:33:05.000000000 +0200
+++ b/php.ini-production 2018-08-03 18:54:50.075801766 +0200
@@ -308,6 +308,10 @@
; http://php.net/open-basedir
;open_basedir =
+; Only executables located in the exec_dir will be allowed to be executed
+; via the exec family of functions.
+exec_dir =
+
; This directive allows you to disable certain functions for security reasons.
; It receives a comma-delimited list of function names.
; http://php.net/disable-functions