[Python-checkins] bpo-23691: Protect the re.finditer() iterator from re-entering (GH-32012)

Mon Mar 21 07:31:08 EDT 2022

https://github.com/python/cpython/commit/1b21b55ee0ea57226c52dc9f3ee3c034a5d1dc7b
commit: 1b21b55ee0ea57226c52dc9f3ee3c034a5d1dc7b
branch: 3.10
author: Miss Islington (bot) <31488909+miss-islington at users.noreply.github.com>
committer: miss-islington <31488909+miss-islington at users.noreply.github.com>
date: 2022年03月21日T04:30:58-07:00
summary:
bpo-23691: Protect the re.finditer() iterator from re-entering (GH-32012)
(cherry picked from commit 08eb754d840696914928355014c2d424131f8835)
Co-authored-by: Serhiy Storchaka <storchaka at gmail.com>
files:
A Misc/NEWS.d/next/Library/2022-03-20-22-13-24.bpo-23691.Nc2TrW.rst
M Modules/_sre.c
M Modules/sre.h

diff --git a/Misc/NEWS.d/next/Library/2022-03-20-22-13-24.bpo-23691.Nc2TrW.rst b/Misc/NEWS.d/next/Library/2022-03-20-22-13-24.bpo-23691.Nc2TrW.rst
new file mode 100644
index 0000000000000..053a2b2709ee8
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2022-03-20-22-13-24.bpo-23691.Nc2TrW.rst
@@ -0,0 +1 @@
+Protect the :func:`re.finditer` iterator from re-entering.
diff --git a/Modules/_sre.c b/Modules/_sre.c
index d21b533530187..911626dafc977 100644
--- a/Modules/_sre.c
+++ b/Modules/_sre.c
@@ -2510,6 +2510,25 @@ scanner_dealloc(ScannerObject* self)
 Py_DECREF(tp);
 }
 
+static int
+scanner_begin(ScannerObject* self)
+{
+ if (self->executing) {
+ PyErr_SetString(PyExc_ValueError,
+ "regular expression scanner already executing");
+ return 0;
+ }
+ self->executing = 1;
+ return 1;
+}
+
+static void
+scanner_end(ScannerObject* self)
+{
+ assert(self->executing);
+ self->executing = 0;
+}
+
 /*[clinic input]
 _sre.SRE_Scanner.match
 
@@ -2527,16 +2546,23 @@ _sre_SRE_Scanner_match_impl(ScannerObject *self, PyTypeObject *cls)
 PyObject* match;
 Py_ssize_t status;
 
- if (state->start == NULL)
+ if (!scanner_begin(self)) {
+ return NULL;
+ }
+ if (state->start == NULL) {
+ scanner_end(self);
 Py_RETURN_NONE;
+ }
 
 state_reset(state);
 
 state->ptr = state->start;
 
 status = sre_match(state, PatternObject_GetCode(self->pattern));
- if (PyErr_Occurred())
+ if (PyErr_Occurred()) {
+ scanner_end(self);
 return NULL;
+ }
 
 match = pattern_new_match(module_state, (PatternObject*) self->pattern,
 state, status);
@@ -2548,6 +2574,7 @@ _sre_SRE_Scanner_match_impl(ScannerObject *self, PyTypeObject *cls)
 state->start = state->ptr;
 }
 
+ scanner_end(self);
 return match;
 }
 
@@ -2569,16 +2596,23 @@ _sre_SRE_Scanner_search_impl(ScannerObject *self, PyTypeObject *cls)
 PyObject* match;
 Py_ssize_t status;
 
- if (state->start == NULL)
+ if (!scanner_begin(self)) {
+ return NULL;
+ }
+ if (state->start == NULL) {
+ scanner_end(self);
 Py_RETURN_NONE;
+ }
 
 state_reset(state);
 
 state->ptr = state->start;
 
 status = sre_search(state, PatternObject_GetCode(self->pattern));
- if (PyErr_Occurred())
+ if (PyErr_Occurred()) {
+ scanner_end(self);
 return NULL;
+ }
 
 match = pattern_new_match(module_state, (PatternObject*) self->pattern,
 state, status);
@@ -2590,6 +2624,7 @@ _sre_SRE_Scanner_search_impl(ScannerObject *self, PyTypeObject *cls)
 state->start = state->ptr;
 }
 
+ scanner_end(self);
 return match;
 }
 
@@ -2607,6 +2642,7 @@ pattern_scanner(_sremodulestate *module_state,
 if (!scanner)
 return NULL;
 scanner->pattern = NULL;
+ scanner->executing = 0;
 
 /* create search state object */
 if (!state_init(&scanner->state, self, string, pos, endpos)) {
diff --git a/Modules/sre.h b/Modules/sre.h
index 9b0d8b190426a..785adbd003e7f 100644
--- a/Modules/sre.h
+++ b/Modules/sre.h
@@ -89,6 +89,7 @@ typedef struct {
 PyObject_HEAD
 PyObject* pattern;
 SRE_STATE state;
+ int executing;
 } ScannerObject;
 
 #endif
