Defer sigalgs selection until the certificate is known.

Previously the signature algorithm was selected when the TLS extension was
parsed (or the client received a certificate request), however the actual
certificate to be used is not known at this stage. This leads to various
problems, including the selection of a signature algorithm that cannot be
used with the certificate key size (as found by jeremy@ via ruby regress).

Instead, store the signature algorithms list and only select a signature
algorithm when we're ready to do signature generation.

Joint work with beck@.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/lib/libssl/ssl_srvr.c b/src/lib/libssl/ssl_srvr.c
index f2aafc3032..745d0228f3 100644
--- a/src/lib/libssl/ssl_srvr.c
+++ b/src/lib/libssl/ssl_srvr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_srvr.c,v 1.65 2019/03/25 16:35:48 jsing Exp $ */
+/* $OpenBSD: ssl_srvr.c,v 1.66 2019/03/25 17:21:18 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -2177,7 +2177,7 @@ ssl3_get_cert_verify(SSL *s)
                         al = SSL_AD_DECODE_ERROR;
                         goto f_err;
                 }
-                if (!ssl_sigalg_pkey_ok(sigalg, pkey)) {
+                if (!ssl_sigalg_pkey_ok(sigalg, pkey, 0)) {
                         SSLerror(s, SSL_R_WRONG_SIGNATURE_TYPE);
                         al = SSL_AD_DECODE_ERROR;
                         goto f_err;