Issue #28732: Raise ValueError when argv[0] is empty

2 files changed, 50 insertions, 2 deletions

diff --git a/Lib/test/test_os.py b/Lib/test/test_os.py
index 9194a8a..e9fdb07 100644
--- a/Lib/test/test_os.py
+++ b/Lib/test/test_os.py
@@ -1481,8 +1481,16 @@ class ExecTests(unittest.TestCase):
         self.assertRaises(OSError, os.execvpe, 'no such app-',
                           ['no such app-'], None)
 
+    def test_execv_with_bad_arglist(self):
+        self.assertRaises(ValueError, os.execv, 'notepad', ())
+        self.assertRaises(ValueError, os.execv, 'notepad', [])
+        self.assertRaises(ValueError, os.execv, 'notepad', ('',))
+        self.assertRaises(ValueError, os.execv, 'notepad', [''])
+
     def test_execvpe_with_bad_arglist(self):
         self.assertRaises(ValueError, os.execvpe, 'notepad', [], None)
+        self.assertRaises(ValueError, os.execvpe, 'notepad', [], {})
+        self.assertRaises(ValueError, os.execvpe, 'notepad', [''], {})
 
     @unittest.skipUnless(hasattr(os, '_execvpe'),
                          "No internal os._execvpe function to test.")
@@ -2325,23 +2333,29 @@ class SpawnTests(unittest.TestCase):
     def test_spawnl_noargs(self):
         args = self.create_args()
         self.assertRaises(ValueError, os.spawnl, os.P_NOWAIT, args[0])
+        self.assertRaises(ValueError, os.spawnl, os.P_NOWAIT, args[0], '')
 
     @requires_os_func('spawnle')
-    def test_spawnl_noargs(self):
+    def test_spawnle_noargs(self):
         args = self.create_args()
         self.assertRaises(ValueError, os.spawnle, os.P_NOWAIT, args[0], {})
+        self.assertRaises(ValueError, os.spawnle, os.P_NOWAIT, args[0], '', {})
 
     @requires_os_func('spawnv')
     def test_spawnv_noargs(self):
         args = self.create_args()
         self.assertRaises(ValueError, os.spawnv, os.P_NOWAIT, args[0], ())
         self.assertRaises(ValueError, os.spawnv, os.P_NOWAIT, args[0], [])
+        self.assertRaises(ValueError, os.spawnv, os.P_NOWAIT, args[0], ('',))
+        self.assertRaises(ValueError, os.spawnv, os.P_NOWAIT, args[0], [''])
 
     @requires_os_func('spawnve')
-    def test_spawnv_noargs(self):
+    def test_spawnve_noargs(self):
         args = self.create_args()
         self.assertRaises(ValueError, os.spawnve, os.P_NOWAIT, args[0], (), {})
         self.assertRaises(ValueError, os.spawnve, os.P_NOWAIT, args[0], [], {})
+        self.assertRaises(ValueError, os.spawnve, os.P_NOWAIT, args[0], ('',), {})
+        self.assertRaises(ValueError, os.spawnve, os.P_NOWAIT, args[0], [''], {})
 
 # The introduction of this TestCase caused at least two different errors on
 # *nix buildbots. Temporarily skip this to let the buildbots move along.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 0482f2b..acef3c3 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -4916,12 +4916,20 @@ os_execv_impl(PyObject *module, path_t *path, PyObject *argv)
     if (argvlist == NULL) {
         return NULL;
     }
+    if (!argvlist[0][0]) {
+        PyErr_SetString(PyExc_ValueError,
+            "execv() arg 2 first element cannot be empty");
+        free_string_array(argvlist, argc);
+        return NULL;
+    }
 
+    _Py_BEGIN_SUPPRESS_IPH
 #ifdef HAVE_WEXECV
     _wexecv(path->wide, argvlist);
 #else
     execv(path->narrow, argvlist);
 #endif
+    _Py_END_SUPPRESS_IPH
 
     /* If we get here it's definitely an error */
 
@@ -4961,6 +4969,11 @@ os_execve_impl(PyObject *module, path_t *path, PyObject *argv, PyObject *env)
         goto fail;
     }
     argc = PySequence_Size(argv);
+    if (argc < 1) {
+        PyErr_SetString(PyExc_ValueError, "execve: argv must not be empty");
+        return NULL;
+    }
+
     if (!PyMapping_Check(env)) {
         PyErr_SetString(PyExc_TypeError,
                         "execve: environment must be a mapping object");
@@ -4971,11 +4984,17 @@ os_execve_impl(PyObject *module, path_t *path, PyObject *argv, PyObject *env)
     if (argvlist == NULL) {
         goto fail;
     }
+    if (!argvlist[0][0]) {
+        PyErr_SetString(PyExc_ValueError,
+            "execve: argv first element cannot be empty");
+        goto fail;
+    }
 
     envlist = parse_envlist(env, &envc);
     if (envlist == NULL)
         goto fail;
 
+    _Py_BEGIN_SUPPRESS_IPH
 #ifdef HAVE_FEXECVE
     if (path->fd > -1)
         fexecve(path->fd, argvlist, envlist);
@@ -4986,6 +5005,7 @@ os_execve_impl(PyObject *module, path_t *path, PyObject *argv, PyObject *env)
 #else
         execve(path->narrow, argvlist, envlist);
 #endif
+    _Py_END_SUPPRESS_IPH
 
     /* If we get here it's definitely an error */
 
@@ -5061,6 +5081,13 @@ os_spawnv_impl(PyObject *module, int mode, path_t *path, PyObject *argv)
                 "spawnv() arg 2 must contain only strings");
             return NULL;
         }
+        if (i == 0 && !argvlist[0][0]) {
+            free_string_array(argvlist, i);
+            PyErr_SetString(
+                PyExc_ValueError,
+                "spawnv() arg 2 first element cannot be empty");
+            return NULL;
+        }
     }
     argvlist[argc] = NULL;
 
@@ -5155,6 +5182,13 @@ os_spawnve_impl(PyObject *module, int mode, path_t *path, PyObject *argv,
             lastarg = i;
             goto fail_1;
         }
+        if (i == 0 && !argvlist[0][0]) {
+            lastarg = i;
+            PyErr_SetString(
+                PyExc_ValueError,
+                "spawnv() arg 2 first element cannot be empty");
+            goto fail_1;
+        }
     }
     lastarg = argc;
     argvlist[argc] = NULL;