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bpo-40645: restrict HMAC key len to INT_MAX #20238

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Merged
miss-islington merged 1 commit into from
May 19, 2020
Merged

bpo-40645: restrict HMAC key len to INT_MAX #20238

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8 changes: 7 additions & 1 deletion Modules/_hashopenssl.c
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Original file line number Diff line number Diff line change
Expand Up @@ -1403,6 +1403,12 @@ _hashlib_hmac_new_impl(PyObject *module, Py_buffer *key, PyObject *msg_obj,
HMACobject *self = NULL;
int r;

if (key->len > INT_MAX) {
PyErr_SetString(PyExc_OverflowError,
"key is too long.");

@vstinner vstinner May 19, 2020 •
edited
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"2 GB key should be enough for everyone" :-D

return NULL;
}

if ((digestmod == NULL) || !strlen(digestmod)) {
PyErr_SetString(
PyExc_TypeError, "Missing required parameter 'digestmod'.");
Expand All @@ -1424,7 +1430,7 @@ _hashlib_hmac_new_impl(PyObject *module, Py_buffer *key, PyObject *msg_obj,
r = HMAC_Init_ex(
ctx,
(const char*)key->buf,
key->len,
(int)key->len,
digest,
NULL /*impl*/);
if (r == 0) {
Expand Down