bpo-30622: Improve NPN support detection (#5859)
The ssl module now detects missing NPN support in LibreSSL.
Co-Authored-By: Bernard Spil <brnrd@FreeBSD.org>
Signed-off-by: Christian Heimes <christian@python.org>
diff --git a/Modules/_ssl.c b/Modules/_ssl.c
index 2136cbd..ed6b7a8 100644
--- a/Modules/_ssl.c
+++ b/Modules/_ssl.c
@@ -160,6 +160,19 @@
# define HAVE_ALPN
#endif
+/* We cannot rely on OPENSSL_NO_NEXTPROTONEG because LibreSSL 2.6.1 dropped
+ * NPN support but did not set OPENSSL_NO_NEXTPROTONEG for compatibility
+ * reasons. The check for TLSEXT_TYPE_next_proto_neg works with
+ * OpenSSL 1.0.1+ and LibreSSL.
+ */
+#ifdef OPENSSL_NO_NEXTPROTONEG
+# define HAVE_NPN 0
+#elif defined(TLSEXT_TYPE_next_proto_neg)
+# define HAVE_NPN 1
+#else
+# define HAVE_NPN 0
+# endif
+
#ifndef INVALID_SOCKET /* MS defines this */
#define INVALID_SOCKET (-1)
#endif
@@ -328,7 +341,7 @@
typedef struct {
PyObject_HEAD
SSL_CTX *ctx;
-#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
+#ifdef HAVE_NPN
unsigned char *npn_protocols;
int npn_protocols_len;
#endif
@@ -1909,7 +1922,7 @@
return PyUnicode_FromString(version);
}
-#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
+#ifdef HAVE_NPN
/*[clinic input]
_ssl._SSLSocket.selected_npn_protocol
[clinic start generated code]*/
@@ -2874,7 +2887,7 @@
self->ctx = ctx;
self->hostflags = X509_CHECK_FLAG_NO_PARTIAL_WILDCARDS;
self->protocol = proto_version;
-#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
+#ifdef HAVE_NPN
self->npn_protocols = NULL;
#endif
#ifdef HAVE_ALPN
@@ -3013,7 +3026,7 @@
PyObject_GC_UnTrack(self);
context_clear(self);
SSL_CTX_free(self->ctx);
-#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
+#ifdef HAVE_NPN
PyMem_FREE(self->npn_protocols);
#endif
#ifdef HAVE_ALPN
@@ -3091,7 +3104,7 @@
#endif
-#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG) || defined(HAVE_ALPN)
+#if defined(HAVE_NPN) || defined(HAVE_ALPN)
static int
do_protocol_selection(int alpn, unsigned char **out, unsigned char *outlen,
const unsigned char *server_protocols, unsigned int server_protocols_len,
@@ -3117,7 +3130,7 @@
}
#endif
-#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
+#ifdef HAVE_NPN
/* this callback gets passed to SSL_CTX_set_next_protos_advertise_cb */
static int
_advertiseNPN_cb(SSL *s,
@@ -3160,7 +3173,7 @@
Py_buffer *protos)
/*[clinic end generated code: output=72b002c3324390c6 input=319fcb66abf95bd7]*/
{
-#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
+#ifdef HAVE_NPN
PyMem_Free(self->npn_protocols);
self->npn_protocols = PyMem_Malloc(protos->len);
if (self->npn_protocols == NULL)
@@ -5705,7 +5718,7 @@
Py_INCREF(r);
PyModule_AddObject(m, "HAS_ECDH", r);
-#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
+#ifdef HAVE_NPN
r = Py_True;
#else
r = Py_False;