diff --git a/Misc/NEWS.d/next/Core and Builtins/2018-09-27-11-10-02.bpo-34824.VLlCaU.rst b/Misc/NEWS.d/next/Core and Builtins/2018-09-27-11-10-02.bpo-34824.VLlCaU.rst new file mode 100644 index 00000000000..fe95b8973c0 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2018-09-27-11-10-02.bpo-34824.VLlCaU.rst @@ -0,0 +1,2 @@ +Fix a possible null pointer dereference in Modules/_ssl.c. Patch by Zackery +Spytz. diff --git a/Modules/_ssl.c b/Modules/_ssl.c index 4253e2a7720..f9d1b8c3087 100644 --- a/Modules/_ssl.c +++ b/Modules/_ssl.c @@ -4711,12 +4711,17 @@ _ssl_MemoryBIO_read_impl(PySSLMemoryBIO *self, int len) return result; nbytes = BIO_read(self->bio, PyBytes_AS_STRING(result), len); - /* There should never be any short reads but check anyway. */ - if ((nbytes < len) && (_PyBytes_Resize(&result, len) < 0)) { + if (nbytes < 0) { Py_DECREF(result); + _setSSLError(NULL, 0, __FILE__, __LINE__); return NULL; } + /* There should never be any short reads but check anyway. */ + if (nbytes < len) { + _PyBytes_Resize(&result, nbytes); + } + return result; }