Track the sigalgs used by ourselves and our peer.

Move the sigalg pointer from SSL_HANDSHAKE_TLS13 to SSL_HANDSHAKE, naming
it our_sigalg, adding an equivalent peer_sigalg. Adjust the TLSv1.3 code
that records our signature algorithm. Add code to record the signature
algorithm used by our peer.

Needed for upcoming API additions.

ok tb@

3 files changed, 14 insertions, 9 deletions

diff --git a/src/lib/libssl/ssl_locl.h b/src/lib/libssl/ssl_locl.h
index 5f99c08cc9..200219c141 100644
--- a/src/lib/libssl/ssl_locl.h
+++ b/src/lib/libssl/ssl_locl.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_locl.h,v 1.351 2021/06/23 11:12:33 tb Exp $ */
+/* $OpenBSD: ssl_locl.h,v 1.352 2021/06/27 19:23:51 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -444,9 +444,8 @@ typedef struct ssl_handshake_tls13_st {
         int use_legacy;
         int hrr;
 
-        /* Certificate and sigalg selected for use (static pointers). */
+        /* Certificate selected for use (static pointer). */
         const CERT_PKEY *cpk;
-        const struct ssl_sigalg *sigalg;
 
         /* Version proposed by peer server. */
         uint16_t server_version;
@@ -503,6 +502,10 @@ typedef struct ssl_handshake_st {
         /* Extensions seen in this handshake. */
         uint32_t extensions_seen;
 
+        /* Signature algorithms selected for use (static pointers). */
+        const struct ssl_sigalg *our_sigalg;
+        const struct ssl_sigalg *peer_sigalg;
+
         /* sigalgs offered in this handshake in wire form */
         uint8_t *sigalgs;
         size_t sigalgs_len;
diff --git a/src/lib/libssl/tls13_client.c b/src/lib/libssl/tls13_client.c
index 644b16e26c..4ba0dd92f2 100644
--- a/src/lib/libssl/tls13_client.c
+++ b/src/lib/libssl/tls13_client.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls13_client.c,v 1.82 2021/06/27 18:15:35 jsing Exp $ */
+/* $OpenBSD: tls13_client.c,v 1.83 2021/06/27 19:23:51 jsing Exp $ */
 /*
  * Copyright (c) 2018, 2019 Joel Sing <jsing@openbsd.org>
  *
@@ -697,6 +697,7 @@ tls13_server_certificate_verify_recv(struct tls13_ctx *ctx, CBS *cbs)
                 goto err;
         if (!ssl_sigalg_pkey_ok(sigalg, pkey, 1))
                 goto err;
+        ctx->hs->peer_sigalg = sigalg;
 
         if (CBS_len(&signature) > EVP_PKEY_size(pkey))
                 goto err;
@@ -898,7 +899,7 @@ tls13_client_certificate_send(struct tls13_ctx *ctx, CBB *cbb)
                 goto err;
 
         ctx->hs->tls13.cpk = cpk;
-        ctx->hs->tls13.sigalg = sigalg;
+        ctx->hs->our_sigalg = sigalg;
 
         if (!CBB_add_u8_length_prefixed(cbb, &cert_request_context))
                 goto err;
@@ -949,7 +950,7 @@ tls13_client_certificate_verify_send(struct tls13_ctx *ctx, CBB *cbb)
 
         if ((cpk = ctx->hs->tls13.cpk) == NULL)
                 goto err;
-        if ((sigalg = ctx->hs->tls13.sigalg) == NULL)
+        if ((sigalg = ctx->hs->our_sigalg) == NULL)
                 goto err;
         pkey = cpk->privatekey;
 
diff --git a/src/lib/libssl/tls13_server.c b/src/lib/libssl/tls13_server.c
index b68a2f9294..18cb056755 100644
--- a/src/lib/libssl/tls13_server.c
+++ b/src/lib/libssl/tls13_server.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: tls13_server.c,v 1.80 2021/06/27 18:15:35 jsing Exp $ */
+/* $OpenBSD: tls13_server.c,v 1.81 2021/06/27 19:23:51 jsing Exp $ */
 /*
  * Copyright (c) 2019, 2020 Joel Sing <jsing@openbsd.org>
  * Copyright (c) 2020 Bob Beck <beck@openbsd.org>
@@ -635,7 +635,7 @@ tls13_server_certificate_send(struct tls13_ctx *ctx, CBB *cbb)
         }
 
         ctx->hs->tls13.cpk = cpk;
-        ctx->hs->tls13.sigalg = sigalg;
+        ctx->hs->our_sigalg = sigalg;
 
         if ((chain = cpk->chain) == NULL)
                 chain = s->ctx->extra_certs;
@@ -708,7 +708,7 @@ tls13_server_certificate_verify_send(struct tls13_ctx *ctx, CBB *cbb)
 
         if ((cpk = ctx->hs->tls13.cpk) == NULL)
                 goto err;
-        if ((sigalg = ctx->hs->tls13.sigalg) == NULL)
+        if ((sigalg = ctx->hs->our_sigalg) == NULL)
                 goto err;
         pkey = cpk->privatekey;
 
@@ -996,6 +996,7 @@ tls13_client_certificate_verify_recv(struct tls13_ctx *ctx, CBS *cbs)
                 goto err;
         if (!ssl_sigalg_pkey_ok(sigalg, pkey, 1))
                 goto err;
+        ctx->hs->peer_sigalg = sigalg;
 
         if (CBS_len(&signature) > EVP_PKEY_size(pkey))
                 goto err;