[3.9] bpo-41056: Fix a possible MemoryError leak within zoneinfo. (GH-21007)

pganssle · gpshead · web-flow · commit 6c5635610961 · 2020-06-24T11:58:50.000-04:00
This was detected by our Coverity scan as a REVERSE_INULL issue. Automerge-Triggered-By: @gpshead (cherry picked from commit d780fa7) Co-authored-by: Gregory P. Smith <greg@krypto.org>
diff --git a/Misc/NEWS.d/next/Library/2020-06-20-18-33-03.bpo-41056.gTH4Bq.rst b/Misc/NEWS.d/next/Library/2020-06-20-18-33-03.bpo-41056.gTH4Bq.rst
@@ -0,0 +1 @@
+Fixed an instance where a MemoryError within the zoneinfo module might not be reported or not reported at its source. (found by Coverity)
diff --git a/Modules/_zoneinfo.c b/Modules/_zoneinfo.c
@@ -278,13 +278,11 @@ zoneinfo_new(PyTypeObject *type, PyObject *args, PyObject *kw)
 
         instance =
             PyObject_CallMethod(weak_cache, "setdefault", "OO", key, tmp);
-        ((PyZoneInfo_ZoneInfo *)instance)->source = SOURCE_CACHE;
-
         Py_DECREF(tmp);
-
         if (instance == NULL) {
             return NULL;
         }
+        ((PyZoneInfo_ZoneInfo *)instance)->source = SOURCE_CACHE;
     }
 
     update_strong_cache(type, key, instance);
@@ -1622,7 +1620,7 @@ parse_abbr(const char *const p, PyObject **abbr)
     }
 
     *abbr = PyUnicode_FromStringAndSize(str_start, str_end - str_start);
-    if (abbr == NULL) {
+    if (*abbr == NULL) {
         return -1;
     }
 

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+Fixed an instance where a MemoryError within the zoneinfo module might not be reported or not reported at its source. (found by Coverity)`
Original file line number	Diff line number	Diff line change
`@@ -278,13 +278,11 @@ zoneinfo_new(PyTypeObject type, PyObject args, PyObject *kw)`
`278`	`278`
`279`	`279`	`instance =`
`280`	`280`	`PyObject_CallMethod(weak_cache, "setdefault", "OO", key, tmp);`
`281`		`- ((PyZoneInfo_ZoneInfo *)instance)->source = SOURCE_CACHE;`
`282`		`-`
`283`	`281`	`Py_DECREF(tmp);`
`284`		`-`
`285`	`282`	`if (instance == NULL) {`
`286`	`283`	`return NULL;`
`287`	`284`	`}`
	`285`	`+ ((PyZoneInfo_ZoneInfo *)instance)->source = SOURCE_CACHE;`
`288`	`286`	`}`
`289`	`287`
`290`	`288`	`update_strong_cache(type, key, instance);`
`@@ -1622,7 +1620,7 @@ parse_abbr(const char const p, PyObject *abbr)`
`1622`	`1620`	`}`
`1623`	`1621`
`1624`	`1622`	`*abbr = PyUnicode_FromStringAndSize(str_start, str_end - str_start);`
`1625`		`- if (abbr == NULL) {`
	`1623`	`+ if (*abbr == NULL) {`
`1626`	`1624`	`return -1;`
`1627`	`1625`	`}`
`1628`	`1626`