bpo-30622: Change NPN detection: (#2079)
* Change NPN detection:
Version breakdown, support disabled (pre-patch/post-patch):
- pre-1.0.1: OPENSSL_NPN_NEGOTIATED will not be defined -> False/False
- 1.0.1 and 1.0.2: OPENSSL_NPN_NEGOTIATED will not be defined ->
False/False
- 1.1.0+: OPENSSL_NPN_NEGOTIATED will be defined and
OPENSSL_NO_NEXTPROTONEG will be defined -> True/False
Version breakdown support enabled (pre-patch/post-patch):
- pre-1.0.1: OPENSSL_NPN_NEGOTIATED will not be defined -> False/False
- 1.0.1 and 1.0.2: OPENSSL_NPN_NEGOTIATED will be defined and
OPENSSL_NO_NEXTPROTONEG will not be defined -> True/True
- 1.1.0+: OPENSSL_NPN_NEGOTIATED will be defined and
OPENSSL_NO_NEXTPROTONEG will not be defined -> True/True
* Refine NPN guard:
- If NPN is disabled, but ALPN is available we need our callback
- Make clinic's ssl behave the same way
This created a working ssl module for me, with NPN disabled and ALPN
enabled for OpenSSL 1.1.0f.
Concerns to address:
The initial commit for NPN support into OpenSSL [1], had the
OPENSSL_NPN_* variables defined inside the OPENSSL_NO_NEXTPROTONEG
guard. The question is if that ever made it into a release.
This would need an ugly hack, something like:
#if defined(OPENSSL_NO_NEXTPROTONEG) && \
!defined(OPENSSL_NPN_NEGOTIATED)
# define OPENSSL_NPN_UNSUPPORTED 0
# define OPENSSL_NPN_NEGOTIATED 1
# define OPENSSL_NPN_NO_OVERLAP 2
#endif
[1] https://github.com/openssl/openssl/commit/68b33cc5c7
diff --git a/Modules/_ssl.c b/Modules/_ssl.c
index e8abcb2..b7761d7 100644
--- a/Modules/_ssl.c
+++ b/Modules/_ssl.c
@@ -315,7 +315,7 @@
typedef struct {
PyObject_HEAD
SSL_CTX *ctx;
-#ifdef OPENSSL_NPN_NEGOTIATED
+#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
unsigned char *npn_protocols;
int npn_protocols_len;
#endif
@@ -1697,7 +1697,7 @@
return PyUnicode_FromString(version);
}
-#ifdef OPENSSL_NPN_NEGOTIATED
+#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
/*[clinic input]
_ssl._SSLSocket.selected_npn_protocol
[clinic start generated code]*/
@@ -2647,7 +2647,7 @@
return NULL;
}
self->ctx = ctx;
-#ifdef OPENSSL_NPN_NEGOTIATED
+#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
self->npn_protocols = NULL;
#endif
#ifdef HAVE_ALPN
@@ -2782,7 +2782,7 @@
PyObject_GC_UnTrack(self);
context_clear(self);
SSL_CTX_free(self->ctx);
-#ifdef OPENSSL_NPN_NEGOTIATED
+#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
PyMem_FREE(self->npn_protocols);
#endif
#ifdef HAVE_ALPN
@@ -2860,7 +2860,7 @@
#endif
-#ifdef OPENSSL_NPN_NEGOTIATED
+#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG) || 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,
@@ -2884,7 +2884,9 @@
return SSL_TLSEXT_ERR_OK;
}
+#endif
+#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
/* this callback gets passed to SSL_CTX_set_next_protos_advertise_cb */
static int
_advertiseNPN_cb(SSL *s,
@@ -2927,7 +2929,7 @@
Py_buffer *protos)
/*[clinic end generated code: output=72b002c3324390c6 input=319fcb66abf95bd7]*/
{
-#ifdef OPENSSL_NPN_NEGOTIATED
+#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
PyMem_Free(self->npn_protocols);
self->npn_protocols = PyMem_Malloc(protos->len);
if (self->npn_protocols == NULL)
@@ -5397,7 +5399,7 @@
Py_INCREF(r);
PyModule_AddObject(m, "HAS_ECDH", r);
-#ifdef OPENSSL_NPN_NEGOTIATED
+#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
r = Py_True;
#else
r = Py_False;
diff --git a/Modules/clinic/_ssl.c.h b/Modules/clinic/_ssl.c.h
index ac205f6..fa4f7e2 100644
--- a/Modules/clinic/_ssl.c.h
+++ b/Modules/clinic/_ssl.c.h
@@ -132,7 +132,7 @@
return _ssl__SSLSocket_version_impl(self);
}
-#if defined(OPENSSL_NPN_NEGOTIATED)
+#if defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG)
PyDoc_STRVAR(_ssl__SSLSocket_selected_npn_protocol__doc__,
"selected_npn_protocol($self, /)\n"
@@ -151,7 +151,7 @@
return _ssl__SSLSocket_selected_npn_protocol_impl(self);
}
-#endif /* defined(OPENSSL_NPN_NEGOTIATED) */
+#endif /* defined(OPENSSL_NPN_NEGOTIATED) && !defined(OPENSSL_NO_NEXTPROTONEG) */
#if defined(HAVE_ALPN)