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, 5 insertions, 1 deletions

diff --git a/src/lib/libssl/ssl_locl.h b/src/lib/libssl/ssl_locl.h
index 9d06deeb7a..44abb6d6da 100644
--- a/src/lib/libssl/ssl_locl.h
+++ b/src/lib/libssl/ssl_locl.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_locl.h,v 1.241 2019/03/25 16:37:52 jsing Exp $ */
+/* $OpenBSD: ssl_locl.h,v 1.242 2019/03/25 17:21:18 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -432,6 +432,10 @@ typedef struct ssl_handshake_st {
 
         /* Extensions seen in this handshake. */
         uint32_t extensions_seen;
+
+        /* sigalgs offered in this handshake in wire form */
+        size_t sigalgs_len;
+        uint8_t *sigalgs;
 } SSL_HANDSHAKE;
 
 typedef struct ssl_handshake_tls13_st {