From b77463f5b274bdee3fd889ca748cafac1330ba70 Mon Sep 17 00:00:00 2001
From: Benoit Favre <benoit.favre@lis-lab.fr>
Date: Fri, 28 Feb 2025 15:07:20 +0100
Subject: [PATCH] jailed exec: add support for __builtins__ global

---
 src/interpreter/ceval.c | 56 +++++++++++++++++++++++++++++++++++++++++
 tests/66_eval.py        | 18 +++++++++++++
 2 files changed, 74 insertions(+)

diff --git a/src/interpreter/ceval.c b/src/interpreter/ceval.c
index dec2f112..b7d9e619 100644
--- a/src/interpreter/ceval.c
+++ b/src/interpreter/ceval.c
@@ -253,6 +253,20 @@ FrameResult VM__run_top_frame(VM* self) {
                 }
                 if(res == -1) goto __ERROR;
                 // builtins
+                if (self->max_steps > 0) {
+                    int res = Frame__getglobal(frame, py_name("__builtins__"));
+                    if (res == 1) {
+                        py_Ref builtins = &self->last_retval;
+                        if(!py_istype(builtins, tp_dict)) { return TypeError("__builtins__ must be a dict object"); }
+                        res = py_dict_getitem(builtins, py_name2ref(name));
+                        if (res == 1) {
+                            PUSH(&self->last_retval);
+                            DISPATCH();
+                        }
+                    }
+                    NameError(name);
+                    goto __ERROR;
+                }
                 py_Ref tmp = py_getdict(&self->builtins, name);
                 if(tmp != NULL) {
                     PUSH(tmp);
@@ -275,6 +289,20 @@ FrameResult VM__run_top_frame(VM* self) {
                 }
                 if(res == -1) goto __ERROR;
 
+                if (self->max_steps > 0) {
+                    int res = Frame__getglobal(frame, py_name("__builtins__"));
+                    if (res == 1) {
+                        py_Ref builtins = &self->last_retval;
+                        if(!py_istype(builtins, tp_dict)) { return TypeError("__builtins__ must be a dict object"); }
+                        res = py_dict_getitem(builtins, py_name2ref(name));
+                        if (res == 1) {
+                            PUSH(&self->last_retval);
+                            DISPATCH();
+                        }
+                    }
+                    NameError(name);
+                    goto __ERROR;
+                }
                 tmp = py_getdict(&self->builtins, name);
                 if(tmp != NULL) {
                     PUSH(tmp);
@@ -291,6 +319,20 @@ FrameResult VM__run_top_frame(VM* self) {
                     DISPATCH();
                 }
                 if(res == -1) goto __ERROR;
+                if (self->max_steps > 0) {
+                    int res = Frame__getglobal(frame, py_name("__builtins__"));
+                    if (res == 1) {
+                        py_Ref builtins = &self->last_retval;
+                        if(!py_istype(builtins, tp_dict)) { return TypeError("__builtins__ must be a dict object"); }
+                        res = py_dict_getitem(builtins, py_name2ref(name));
+                        if (res == 1) {
+                            PUSH(&self->last_retval);
+                            DISPATCH();
+                        }
+                    }
+                    NameError(name);
+                    goto __ERROR;
+                }
                 py_Ref tmp = py_getdict(&self->builtins, name);
                 if(tmp != NULL) {
                     PUSH(tmp);
@@ -322,6 +364,20 @@ FrameResult VM__run_top_frame(VM* self) {
                     DISPATCH();
                 }
                 if(res == -1) goto __ERROR;
+                if (self->max_steps > 0) {
+                    int res = Frame__getglobal(frame, py_name("__builtins__"));
+                    if (res == 1) {
+                        py_Ref builtins = &self->last_retval;
+                        if(!py_istype(builtins, tp_dict)) { return TypeError("__builtins__ must be a dict object"); }
+                        res = py_dict_getitem(builtins, py_name2ref(name));
+                        if (res == 1) {
+                            PUSH(&self->last_retval);
+                            DISPATCH();
+                        }
+                    }
+                    NameError(name);
+                    goto __ERROR;
+                }
                 tmp = py_getdict(&self->builtins, name);
                 if(tmp) {
                     PUSH(tmp);
diff --git a/tests/66_eval.py b/tests/66_eval.py
index dd41905f..fcf28255 100644
--- a/tests/66_eval.py
+++ b/tests/66_eval.py
@@ -82,3 +82,21 @@ try:
   exec_jailed(100000, code)
 except Timeout:
   pass
+
+code = '''
+def f():
+  z(1)
+f()
+z(2)
+'''
+res = []
+exec_jailed(100000, code, {'__builtins__': {'z': lambda x: res.append(x)}})
+assert res == [1, 2]
+
+code = '''
+print(1)
+'''
+try:
+  exec_jailed(100000, code, {'__builtins__': {}})
+except NameError:
+  pass