diff options
| -rw-r--r-- | Misc/NEWS.d/next/Security/2020-05-28-06-06-47.bpo-40791.QGZClX.rst | 1 | ||||
| -rw-r--r-- | Modules/operator.c | 2 |
2 files changed, 2 insertions, 1 deletions
diff --git a/Misc/NEWS.d/next/Security/2020-05-28-06-06-47.bpo-40791.QGZClX.rst b/Misc/NEWS.d/next/Security/2020-05-28-06-06-47.bpo-40791.QGZClX.rst new file mode 100644 index 00000000000..69b9de1beae --- /dev/null +++ b/Misc/NEWS.d/next/Security/2020-05-28-06-06-47.bpo-40791.QGZClX.rst @@ -0,0 +1 @@ +Add ``volatile`` to the accumulator variable in ``hmac.compare_digest``, making constant-time-defeating optimizations less likely.
\ No newline at end of file diff --git a/Modules/operator.c b/Modules/operator.c index 7ddd123f405..67011a6a823 100644 --- a/Modules/operator.c +++ b/Modules/operator.c @@ -259,7 +259,7 @@ _tscmp(const unsigned char *a, const unsigned char *b, volatile const unsigned char *left; volatile const unsigned char *right; Py_ssize_t i; - unsigned char result; + volatile unsigned char result; /* loop count depends on length of b */ length = len_b; |