bpo-36398: Fix a possible crash in structseq_repr(). (GH-12492)

ZackerySpytz · serhiy-storchaka · commit 93e8012f2cab · 2019-03-22T09:24:34.000+02:00
If the first PyUnicode_DecodeUTF8() call fails in structseq_repr(),
_PyUnicodeWriter_Dealloc() will be called on an uninitialized
_PyUnicodeWriter.
diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-03-21-22-19-38.bpo-36398.B_jXGe.rst b/Misc/NEWS.d/next/Core and Builtins/2019-03-21-22-19-38.bpo-36398.B_jXGe.rst
@@ -0,0 +1 @@
+Fix a possible crash in ``structseq_repr()``.
diff --git a/Objects/structseq.c b/Objects/structseq.c
@@ -176,7 +176,7 @@ structseq_repr(PyStructSequence *obj)
                                                strlen(typ->tp_name),
                                                NULL);
     if (type_name == NULL) {
-        goto error;
+        return NULL;
     }
 
     _PyUnicodeWriter_Init(&writer);

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	+Fix a possible crash in ``structseq_repr()``.
Original file line number	Diff line number	Diff line change
`@@ -176,7 +176,7 @@ structseq_repr(PyStructSequence *obj)`
`176`	`176`	`strlen(typ->tp_name),`
`177`	`177`	`NULL);`
`178`	`178`	`if (type_name == NULL) {`
`179`		`- goto error;`
	`179`	`+ return NULL;`
`180`	`180`	`}`
`181`	`181`
`182`	`182`	`_PyUnicodeWriter_Init(&writer);`