ssl/npn+alpn: adjust protocol selection to fail if no protocols match

The current behavior causes a server written using rust-openssl to (if
it cannot negotiate a protocol) fallback to the first protocol it has
avaliable.

This makes it impossible to detect protocol mismatches.

This updates our selection to be more similar to how openssl's
s_server behaves: non-matching protocols are not supplied with a
fallback.

Note that some setups may actually want a fallback protocol supplied
via ALPN. To support those cases, we should consider adding a generic
callback that allows protocol selection to be entirely controlled by
the programmer.

For the purposes of having a sane default, however, not supplying a
default (and mimicing s_server's behavior) is the best choice.
This commit is contained in:
Cody P Schafer 2015-09-01 17:09:19 -04:00
parent 164f3f0873
commit 50c5042c70
2 changed files with 8 additions and 5 deletions

View File

@ -167,11 +167,11 @@ macro_rules! import_options {
include!("ssl_options.rs"); include!("ssl_options.rs");
#[cfg(feature = "npn")] #[cfg(any(feature = "npn", feature = "alpn"))]
pub const OPENSSL_NPN_UNSUPPORTED: c_int = 0; pub const OPENSSL_NPN_UNSUPPORTED: c_int = 0;
#[cfg(feature = "npn")] #[cfg(any(feature = "npn", feature = "alpn"))]
pub const OPENSSL_NPN_NEGOTIATED: c_int = 1; pub const OPENSSL_NPN_NEGOTIATED: c_int = 1;
#[cfg(feature = "npn")] #[cfg(any(feature = "npn", feature = "alpn"))]
pub const OPENSSL_NPN_NO_OVERLAP: c_int = 2; pub const OPENSSL_NPN_NO_OVERLAP: c_int = 2;
pub const V_ASN1_GENERALIZEDTIME: c_int = 24; pub const V_ASN1_GENERALIZEDTIME: c_int = 24;

View File

@ -308,8 +308,11 @@ unsafe fn select_proto_using(ssl: *mut ffi::SSL,
let client_len = protocols.len() as c_uint; let client_len = protocols.len() as c_uint;
// Finally, let OpenSSL find a protocol to be used, by matching the given server and // Finally, let OpenSSL find a protocol to be used, by matching the given server and
// client lists. // client lists.
ffi::SSL_select_next_proto(out, outlen, inbuf, inlen, client, client_len); if ffi::SSL_select_next_proto(out, outlen, inbuf, inlen, client, client_len) != ffi::OPENSSL_NPN_NEGOTIATED {
ffi::SSL_TLSEXT_ERR_OK ffi::SSL_TLSEXT_ERR_NOACK
} else {
ffi::SSL_TLSEXT_ERR_OK
}
} }
/// The function is given as the callback to `SSL_CTX_set_next_proto_select_cb`. /// The function is given as the callback to `SSL_CTX_set_next_proto_select_cb`.