encoding: check overflow while calculating size of JSON escape buffer
The minimum input size to exploit is ~682MB (= INT_MAX / len('\\u0000') * 2)
on 32bit system, which isn't easy to achieve using Python str in 2GB process
address space, but probably doable.
--- a/mercurial/cext/charencode.c Wed Aug 30 20:25:56 2017 +0000
+++ b/mercurial/cext/charencode.c Thu Aug 31 21:56:40 2017 +0900
@@ -294,11 +294,21 @@
return -1;
}
esclen += jsonparanoidlentable[(unsigned char)c];
+ if (esclen < 0) {
+ PyErr_SetString(PyExc_MemoryError,
+ "overflow in jsonescapelen");
+ return -1;
+ }
}
} else {
for (i = 0; i < len; i++) {
char c = buf[i];
esclen += jsonlentable[(unsigned char)c];
+ if (esclen < 0) {
+ PyErr_SetString(PyExc_MemoryError,
+ "overflow in jsonescapelen");
+ return -1;
+ }
}
}
@@ -366,7 +376,7 @@
origlen = PyBytes_GET_SIZE(origstr);
esclen = jsonescapelen(origbuf, origlen, paranoid);
if (esclen < 0)
- return NULL; /* unsupported char found */
+ return NULL; /* unsupported char found or overflow */
if (origlen == esclen) {
Py_INCREF(origstr);
return origstr;