python
diff --git a/‎Lib/test/test_subprocess.py‎
Lines changed: 40 additions & 0 deletions b/‎Lib/test/test_subprocess.py‎
Lines changed: 40 additions & 0 deletions
diff --git a/‎Misc/NEWS‎
Lines changed: 3 additions & 0 deletions b/‎Misc/NEWS‎
Lines changed: 3 additions & 0 deletions
diff --git a/‎Modules/posixmodule.c‎
Lines changed: 6 additions & 0 deletions b/‎Modules/posixmodule.c‎
Lines changed: 6 additions & 0 deletions
diff --git a/‎PC/_subprocess.c‎
Lines changed: 14 additions & 2 deletions b/‎PC/_subprocess.c‎
Lines changed: 14 additions & 2 deletions
@@ -385,6 +385,46 @@ def test_env(self):
         self.addCleanup(p.stdout.close)
         self.assertEqual(p.stdout.read(), "orange")
 
+    def test_invalid_cmd(self):
+        # null character in the command name
+        cmd = sys.executable + '\0'
+        with self.assertRaises(TypeError):
+            subprocess.Popen([cmd, "-c", "pass"])
+
+        # null character in the command argument
+        with self.assertRaises(TypeError):
+            subprocess.Popen([sys.executable, "-c", "pass#\0"])
+
+    def test_invalid_env(self):
+        # null character in the enviroment variable name
+        newenv = os.environ.copy()
+        newenv["FRUIT\0VEGETABLE"] = "cabbage"
+        with self.assertRaises(TypeError):
+            subprocess.Popen([sys.executable, "-c", "pass"], env=newenv)
+
+        # null character in the enviroment variable value
+        newenv = os.environ.copy()
+        newenv["FRUIT"] = "orange\0VEGETABLE=cabbage"
+        with self.assertRaises(TypeError):
+            subprocess.Popen([sys.executable, "-c", "pass"], env=newenv)
+
+        # equal character in the enviroment variable name
+        newenv = os.environ.copy()
+        newenv["FRUIT=ORANGE"] = "lemon"
+        with self.assertRaises(ValueError):
+            subprocess.Popen([sys.executable, "-c", "pass"], env=newenv)
+
+        # equal character in the enviroment variable value
+        newenv = os.environ.copy()
+        newenv["FRUIT"] = "orange=lemon"
+        p = subprocess.Popen([sys.executable, "-c",
+                              'import sys, os;'
+                              'sys.stdout.write(os.getenv("FRUIT"))'],
+                             stdout=subprocess.PIPE,
+                             env=newenv)
+        stdout, stderr = p.communicate()
+        self.assertEqual(stdout, "orange=lemon")
+
     def test_communicate_stdin(self):
         p = subprocess.Popen([sys.executable, "-c",
                               'import sys;'
 
@@ -52,6 +52,9 @@ Extension Modules
 Library
 -------
 
+- [Security] bpo-30730: Prevent environment variables injection in subprocess on
+  Windows.  Prevent passing other environment variables and command arguments.
+
 - [Security] bpo-30694: Upgrade expat copy from 2.2.0 to 2.2.1 to get fixes
   of multiple security vulnerabilities including: CVE-2017-9233 (External
   entity infinite loop DoS), CVE-2016-9063 (Integer overflow, re-fix),
 
@@ -3315,6 +3315,12 @@ posix_execve(PyObject *self, PyObject *args)
         {
             goto fail_2;
         }
+        /* Search from index 1 because on Windows starting '=' is allowed for
+           defining hidden environment variables. */
+        if (*k == '\0' || strchr(k + 1, '=') != NULL) {
+            PyErr_SetString(PyExc_ValueError, "illegal environment variable name");
+            goto fail_2;
+        }
 
 #if defined(PYOS_OS2)
         /* Omit Pseudo-Env Vars that Would Confuse Programs if Passed On */
 
@@ -352,7 +352,7 @@ getenvironment(PyObject* environment)
     p = PyString_AS_STRING(out);
 
     for (i = 0; i < envsize; i++) {
-        int ksize, vsize, totalsize;
+        size_t ksize, vsize, totalsize;
         PyObject* key = PyList_GET_ITEM(keys, i);
         PyObject* value = PyList_GET_ITEM(values, i);
 
@@ -363,10 +363,22 @@ getenvironment(PyObject* environment)
         }
         ksize = PyString_GET_SIZE(key);
         vsize = PyString_GET_SIZE(value);
+        if (strlen(PyString_AS_STRING(key)) != ksize ||
+            strlen(PyString_AS_STRING(value)) != vsize)
+        {
+            PyErr_SetString(PyExc_TypeError, "embedded null character");
+            goto error;
+        }
+        /* Search from index 1 because on Windows starting '=' is allowed for
+           defining hidden environment variables. */
+        if (ksize == 0 || strchr(PyString_AS_STRING(key) + 1, '=') != NULL) {
+            PyErr_SetString(PyExc_ValueError, "illegal environment variable name");
+            goto error;
+        }
         totalsize = (p - PyString_AS_STRING(out)) + ksize + 1 +
                                                      vsize + 1 + 1;
         if (totalsize > PyString_GET_SIZE(out)) {
-            int offset = p - PyString_AS_STRING(out);
+            size_t offset = p - PyString_AS_STRING(out);
             if (_PyString_Resize(&out, totalsize + 1024))
                 goto exit;
             p = PyString_AS_STRING(out) + offset;
Original file line number	Diff line number	Diff line change
`@@ -3315,6 +3315,12 @@ posix_execve(PyObject self, PyObject args)`
`3315`	`3315`	`{`
`3316`	`3316`	`goto fail_2;`
`3317`	`3317`	`}`
	`3318`	`+ /* Search from index 1 because on Windows starting '=' is allowed for`
	`3319`	`+ defining hidden environment variables. */`
	`3320`	`+ if (*k == '\0' \|\| strchr(k + 1, '=') != NULL) {`
	`3321`	`+ PyErr_SetString(PyExc_ValueError, "illegal environment variable name");`
	`3322`	`+ goto fail_2;`
	`3323`	`+ }`
`3318`	`3324`
`3319`	`3325`	`#if defined(PYOS_OS2)`
`3320`	`3326`	`/* Omit Pseudo-Env Vars that Would Confuse Programs if Passed On */`