From 84c53958def0f510e92119fca14d74f94215827a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Mat=C4=9Bj=20Cepl?= <mcepl@cepl.eu>
Date: Tue, 28 Jun 2022 21:17:01 +0200
Subject: Mitigate the Bleichenbacher timing attacks in the RSA decryption API
 (CVE-2020-25657)

Fixes #282
---
 src/SWIG/_m2crypto_wrap.c | 20 ++++++++++++--------
 src/SWIG/_rsa.i           | 20 ++++++++++++--------
 2 files changed, 24 insertions(+), 16 deletions(-)

(limited to 'src')

diff --git a/src/SWIG/_m2crypto_wrap.c b/src/SWIG/_m2crypto_wrap.c
index aba9eb6..a9f30da 100644
--- a/src/SWIG/_m2crypto_wrap.c
+++ b/src/SWIG/_m2crypto_wrap.c
@@ -7040,9 +7040,10 @@ PyObject *rsa_private_encrypt(RSA *rsa, PyObject *from, int padding) {
     tlen = RSA_private_encrypt(flen, (unsigned char *)fbuf,
         (unsigned char *)tbuf, rsa, padding);
     if (tlen == -1) {
-        m2_PyErr_Msg(_rsa_err);
+        ERR_clear_error();
+        PyErr_Clear();
         PyMem_Free(tbuf);
-        return NULL;
+        Py_RETURN_NONE;
     }
 
     ret = PyBytes_FromStringAndSize((const char *)tbuf, tlen);
@@ -7070,9 +7071,10 @@ PyObject *rsa_public_decrypt(RSA *rsa, PyObject *from, int padding) {
     tlen = RSA_public_decrypt(flen, (unsigned char *)fbuf,
         (unsigned char *)tbuf, rsa, padding);
     if (tlen == -1) {
-        m2_PyErr_Msg(_rsa_err);
+        ERR_clear_error();
+        PyErr_Clear();
         PyMem_Free(tbuf);
-        return NULL;
+        Py_RETURN_NONE;
     }
 
     ret = PyBytes_FromStringAndSize((const char *)tbuf, tlen);
@@ -7097,9 +7099,10 @@ PyObject *rsa_public_encrypt(RSA *rsa, PyObject *from, int padding) {
     tlen = RSA_public_encrypt(flen, (unsigned char *)fbuf,
         (unsigned char *)tbuf, rsa, padding);
     if (tlen == -1) {
-        m2_PyErr_Msg(_rsa_err);
+        ERR_clear_error();
+        PyErr_Clear();
         PyMem_Free(tbuf);
-        return NULL;
+        Py_RETURN_NONE;
     }
 
     ret = PyBytes_FromStringAndSize((const char *)tbuf, tlen);
@@ -7124,9 +7127,10 @@ PyObject *rsa_private_decrypt(RSA *rsa, PyObject *from, int padding) {
     tlen = RSA_private_decrypt(flen, (unsigned char *)fbuf,
         (unsigned char *)tbuf, rsa, padding);
     if (tlen == -1) {
-        m2_PyErr_Msg(_rsa_err);
+        ERR_clear_error();
+        PyErr_Clear();
         PyMem_Free(tbuf);
-        return NULL;
+        Py_RETURN_NONE;
     }
     ret = PyBytes_FromStringAndSize((const char *)tbuf, tlen);
 
diff --git a/src/SWIG/_rsa.i b/src/SWIG/_rsa.i
index bc714e0..1377b8b 100644
--- a/src/SWIG/_rsa.i
+++ b/src/SWIG/_rsa.i
@@ -239,9 +239,10 @@ PyObject *rsa_private_encrypt(RSA *rsa, PyObject *from, int padding) {
     tlen = RSA_private_encrypt(flen, (unsigned char *)fbuf,
         (unsigned char *)tbuf, rsa, padding);
     if (tlen == -1) {
-        m2_PyErr_Msg(_rsa_err);
+        ERR_clear_error();
+        PyErr_Clear();
         PyMem_Free(tbuf);
-        return NULL;
+        Py_RETURN_NONE;
     }
 
     ret = PyBytes_FromStringAndSize((const char *)tbuf, tlen);
@@ -269,9 +270,10 @@ PyObject *rsa_public_decrypt(RSA *rsa, PyObject *from, int padding) {
     tlen = RSA_public_decrypt(flen, (unsigned char *)fbuf,
         (unsigned char *)tbuf, rsa, padding);
     if (tlen == -1) {
-        m2_PyErr_Msg(_rsa_err);
+        ERR_clear_error();
+        PyErr_Clear();
         PyMem_Free(tbuf);
-        return NULL;
+        Py_RETURN_NONE;
     }
 
     ret = PyBytes_FromStringAndSize((const char *)tbuf, tlen);
@@ -296,9 +298,10 @@ PyObject *rsa_public_encrypt(RSA *rsa, PyObject *from, int padding) {
     tlen = RSA_public_encrypt(flen, (unsigned char *)fbuf,
         (unsigned char *)tbuf, rsa, padding);
     if (tlen == -1) {
-        m2_PyErr_Msg(_rsa_err);
+        ERR_clear_error();
+        PyErr_Clear();
         PyMem_Free(tbuf);
-        return NULL;
+        Py_RETURN_NONE;
     }
 
     ret = PyBytes_FromStringAndSize((const char *)tbuf, tlen);
@@ -323,9 +326,10 @@ PyObject *rsa_private_decrypt(RSA *rsa, PyObject *from, int padding) {
     tlen = RSA_private_decrypt(flen, (unsigned char *)fbuf,
         (unsigned char *)tbuf, rsa, padding);
     if (tlen == -1) {
-        m2_PyErr_Msg(_rsa_err);
+        ERR_clear_error();
+        PyErr_Clear();
         PyMem_Free(tbuf);
-        return NULL;
+        Py_RETURN_NONE;
     }
     ret = PyBytes_FromStringAndSize((const char *)tbuf, tlen);
 
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