Change ssl_sigalgs_build() to perform sigalg list selection.

Rather that doing sigalg list selection at every call site, pass in the
appropriate TLS version and have ssl_sigalgs_build() perform the sigalg
list selection itself. This reduces code duplication, simplifies the
calling code and is the first step towards internalising the sigalg lists.

ok tb@

4 files changed, 29 insertions, 28 deletions

diff --git a/src/lib/libssl/ssl_sigalgs.c b/src/lib/libssl/ssl_sigalgs.c
index d3ac3d969d..590932bdf6 100644
--- a/src/lib/libssl/ssl_sigalgs.c
+++ b/src/lib/libssl/ssl_sigalgs.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_sigalgs.c,v 1.26 2021/06/27 17:50:06 jsing Exp $ */
+/* $OpenBSD: ssl_sigalgs.c,v 1.27 2021/06/27 17:59:17 jsing Exp $ */
 /*
  * Copyright (c) 2018-2020 Bob Beck <beck@openbsd.org>
  *
@@ -174,6 +174,19 @@ const uint16_t tls12_sigalgs[] = {
 };
 const size_t tls12_sigalgs_len = (sizeof(tls12_sigalgs) / sizeof(tls12_sigalgs[0]));
 
+static void
+ssl_sigalgs_for_version(uint16_t tls_version, const uint16_t **out_values,
+    size_t *out_len)
+{
+        if (tls_version >= TLS1_3_VERSION) {
+                *out_values = tls13_sigalgs;
+                *out_len = tls13_sigalgs_len;
+        } else {
+                *out_values = tls12_sigalgs;
+                *out_len = tls12_sigalgs_len;
+        }
+}
+
 const struct ssl_sigalg *
 ssl_sigalg_lookup(uint16_t sigalg)
 {
@@ -201,10 +214,14 @@ ssl_sigalg(uint16_t sigalg, const uint16_t *values, size_t len)
 }
 
 int
-ssl_sigalgs_build(CBB *cbb, const uint16_t *values, size_t len)
+ssl_sigalgs_build(uint16_t tls_version, CBB *cbb)
 {
+        const uint16_t *values;
+        size_t len;
         size_t i;
 
+        ssl_sigalgs_for_version(tls_version, &values, &len);
+
         /* Add values in order as long as they are supported. */
         for (i = 0; i < len; i++) {
                 /* Do not allow the legacy value for < 1.2 to be used. */
diff --git a/src/lib/libssl/ssl_sigalgs.h b/src/lib/libssl/ssl_sigalgs.h
index db21eda1f8..64a2bd435c 100644
--- a/src/lib/libssl/ssl_sigalgs.h
+++ b/src/lib/libssl/ssl_sigalgs.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_sigalgs.h,v 1.17 2021/06/27 17:45:16 jsing Exp $ */
+/* $OpenBSD: ssl_sigalgs.h,v 1.18 2021/06/27 17:59:17 jsing Exp $ */
 /*
  * Copyright (c) 2018-2019 Bob Beck <beck@openbsd.org>
  *
@@ -75,7 +75,7 @@ extern const size_t tls13_sigalgs_len;
 
 const struct ssl_sigalg *ssl_sigalg_lookup(uint16_t sigalg);
 const struct ssl_sigalg *ssl_sigalg(uint16_t sigalg, const uint16_t *values, size_t len);
-int ssl_sigalgs_build(CBB *cbb, const uint16_t *values, size_t len);
+int ssl_sigalgs_build(uint16_t tls_version, CBB *cbb);
 int ssl_sigalg_pkey_check(uint16_t sigalg, EVP_PKEY *pk);
 int ssl_sigalg_pkey_ok(const struct ssl_sigalg *sigalg, EVP_PKEY *pkey,
     int check_curve);
diff --git a/src/lib/libssl/ssl_srvr.c b/src/lib/libssl/ssl_srvr.c
index c4bcd228ef..93fd8cfb85 100644
--- a/src/lib/libssl/ssl_srvr.c
+++ b/src/lib/libssl/ssl_srvr.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_srvr.c,v 1.111 2021/05/16 14:10:43 jsing Exp $ */
+/* $OpenBSD: ssl_srvr.c,v 1.112 2021/06/27 17:59:17 jsing Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -1671,9 +1671,11 @@ ssl3_send_certificate_request(SSL *s)
                         goto err;
 
                 if (SSL_USE_SIGALGS(s)) {
-                        if (!CBB_add_u16_length_prefixed(&cert_request, &sigalgs))
+                        if (!CBB_add_u16_length_prefixed(&cert_request,
+                            &sigalgs))
                                 goto err;
-                        if (!ssl_sigalgs_build(&sigalgs, tls12_sigalgs, tls12_sigalgs_len))
+                        if (!ssl_sigalgs_build(
+                            S3I(s)->hs.negotiated_tls_version, &sigalgs))
                                 goto err;
                 }
 
diff --git a/src/lib/libssl/ssl_tlsext.c b/src/lib/libssl/ssl_tlsext.c
index 035d6b4564..22932f969d 100644
--- a/src/lib/libssl/ssl_tlsext.c
+++ b/src/lib/libssl/ssl_tlsext.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ssl_tlsext.c,v 1.95 2021/06/11 17:29:48 jsing Exp $ */
+/* $OpenBSD: ssl_tlsext.c,v 1.96 2021/06/27 17:59:17 jsing Exp $ */
 /*
  * Copyright (c) 2016, 2017, 2019 Joel Sing <jsing@openbsd.org>
  * Copyright (c) 2017 Doug Hogan <doug@openbsd.org>
@@ -558,21 +558,12 @@ tlsext_sigalgs_client_needs(SSL *s, uint16_t msg_type)
 int
 tlsext_sigalgs_client_build(SSL *s, uint16_t msg_type, CBB *cbb)
 {
-        const uint16_t *tls_sigalgs = tls12_sigalgs;
-        size_t tls_sigalgs_len = tls12_sigalgs_len;
         CBB sigalgs;
 
-        if (S3I(s)->hs.our_min_tls_version >= TLS1_3_VERSION) {
-                tls_sigalgs = tls13_sigalgs;
-                tls_sigalgs_len = tls13_sigalgs_len;
-        }
-
         if (!CBB_add_u16_length_prefixed(cbb, &sigalgs))
                 return 0;
-
-        if (!ssl_sigalgs_build(&sigalgs, tls_sigalgs, tls_sigalgs_len))
+        if (!ssl_sigalgs_build(S3I(s)->hs.our_min_tls_version, &sigalgs))
                 return 0;
-
         if (!CBB_flush(cbb))
                 return 0;
 
@@ -603,21 +594,12 @@ tlsext_sigalgs_server_needs(SSL *s, uint16_t msg_type)
 int
 tlsext_sigalgs_server_build(SSL *s, uint16_t msg_type, CBB *cbb)
 {
-        const uint16_t *tls_sigalgs = tls12_sigalgs;
-        size_t tls_sigalgs_len = tls12_sigalgs_len;
         CBB sigalgs;
 
-        if (S3I(s)->hs.negotiated_tls_version >= TLS1_3_VERSION) {
-                tls_sigalgs = tls13_sigalgs;
-                tls_sigalgs_len = tls13_sigalgs_len;
-        }
-
         if (!CBB_add_u16_length_prefixed(cbb, &sigalgs))
                 return 0;
-
-        if (!ssl_sigalgs_build(&sigalgs, tls_sigalgs, tls_sigalgs_len))
+        if (!ssl_sigalgs_build(S3I(s)->hs.negotiated_tls_version, &sigalgs))
                 return 0;
-
         if (!CBB_flush(cbb))
                 return 0;