Rename the chain variable to chainidx

This variable represents the index of the cert within the chain, so give it
a name that better represents that.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/2020)

4 files changed, 158 insertions, 146 deletions

diff --git a/ssl/statem/extensions.c b/ssl/statem/extensions.c
index 9a76d8b1fa..0c655256ea 100644
--- a/ssl/statem/extensions.c
+++ b/ssl/statem/extensions.c
@@ -54,14 +54,15 @@ typedef struct extensions_definition_st {
      */
     int (*init)(SSL *s, unsigned int context);
     /* Parse extension sent from client to server */
-    int (*parse_ctos)(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al);
+    int (*parse_ctos)(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al);
     /* Parse extension send from server to client */
-    int (*parse_stoc)(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al);
+    int (*parse_stoc)(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al);
     /* Construct extension sent from server to client */
-    int (*construct_stoc)(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+    int (*construct_stoc)(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                           int *al);
     /* Construct extension sent from client to server */
-    int (*construct_ctos)(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al);
+    int (*construct_ctos)(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
+                          int *al);
     /*
      * Finalise extension after parsing. Always called where an extensions was
      * initialised even if the extension was not present. |sent| is set to 1 if
@@ -441,16 +442,16 @@ int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
  * tls_collect_extensions(). The parser is only run if it is applicable for the
  * given |context| and the parser has not already been run. If this is for a
  * Certificate message, then we also provide the parser with the relevant
- * Certificate |x| and its position in the |chain| with 0 being the first
+ * Certificate |x| and its position in the |chainidx| with 0 being the first
  * Certificate. Returns 1 on success or 0 on failure. In the event of a failure
  * |*al| is populated with a suitable alert code. If an extension is not present
  * this counted as success.
  */
 int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
-                        RAW_EXTENSION *exts, X509 *x, size_t chain, int *al)
+                        RAW_EXTENSION *exts, X509 *x, size_t chainidx, int *al)
 {
     RAW_EXTENSION *currext = &exts[idx];
-    int (*parser)(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al) = NULL;
+    int (*parser)(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al) = NULL;
 
     /* Skip if the extension is not present */
     if (!currext->present)
@@ -479,7 +480,7 @@ int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
         parser = s->server ? extdef->parse_ctos : extdef->parse_stoc;
 
         if (parser != NULL)
-            return parser(s, &currext->data, x, chain, al);
+            return parser(s, &currext->data, x, chainidx, al);
 
         /*
          * If the parser is NULL we fall through to the custom extension
@@ -490,7 +491,7 @@ int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
     /*
      * This is a custom extension. We only allow this if it is a non
      * resumed session on the server side.
-     *
+     *chain
      * TODO(TLS1.3): We only allow old style <=TLS1.2 custom extensions.
      * We're going to need a new mechanism for TLS1.3 to specify which
      * messages to add the custom extensions to.
@@ -512,11 +513,11 @@ int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
  * finalisation for all extensions at the end, whether we collected them or not.
  * Returns 1 for success or 0 for failure. If we are working on a Certificate
  * message then we also pass the Certificate |x| and its position in the
- * |chain|, with 0 being the first certificate. On failure, |*al| is populated
- * with a suitable alert code.
+ * |chainidx|, with 0 being the first certificate. On failure, |*al| is
+ * populated with a suitable alert code.
  */
 int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts, X509 *x,
-                             size_t chain, int *al)
+                             size_t chainidx, int *al)
 {
     size_t i, numexts = OSSL_NELEM(ext_defs);
     const EXTENSION_DEFINITION *thisexd;
@@ -530,7 +531,7 @@ int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts, X509 *x,
 
     /* Parse each extension in turn */
     for (i = 0; i < numexts; i++) {
-        if (!tls_parse_extension(s, i, context, exts, x, chain, al))
+        if (!tls_parse_extension(s, i, context, exts, x, chainidx, al))
             return 0;
     }
 
@@ -551,14 +552,14 @@ int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts, X509 *x,
 /*
  * Construct all the extensions relevant to the current |context| and write
  * them to |pkt|. If this is an extension for a Certificate in a Certificate
- * message, then |x| will be set to the Certificate we are handling, and |chain|
- * will indicate the position in the chain we are processing (with 0 being the
- * first in the chain). Returns 1 on success or 0 on failure. If a failure
- * occurs then |al| is populated with a suitable alert code. On a failure
- * construction stops at the first extension to fail to construct.
+ * message, then |x| will be set to the Certificate we are handling, and
+ * |chainidx| will indicate the position in the chainidx we are processing (with
+ * 0 being the first in the chain). Returns 1 on success or 0 on failure. If a
+ * failure occurs then |al| is populated with a suitable alert code. On a
+ * failure construction stops at the first extension to fail to construct.
  */
 int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
-                             X509 *x, size_t chain, int *al)
+                             X509 *x, size_t chainidx, int *al)
 {
     size_t i;
     int addcustom = 0, min_version, max_version = 0, reason, tmpal;
@@ -613,7 +614,8 @@ int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
     }
 
     for (i = 0, thisexd = ext_defs; i < OSSL_NELEM(ext_defs); i++, thisexd++) {
-        int (*construct)(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al);
+        int (*construct)(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
+                         int *al);
 
         /* Skip if not relevant for our context */
         if ((thisexd->context & context) == 0)
@@ -640,7 +642,7 @@ int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
                 || construct == NULL)
             continue;
 
-        if (!construct(s, pkt, x, chain, &tmpal))
+        if (!construct(s, pkt, x, chainidx, &tmpal))
             goto err;
     }
 
diff --git a/ssl/statem/extensions_clnt.c b/ssl/statem/extensions_clnt.c
index 2a9a182409..277e0624a4 100644
--- a/ssl/statem/extensions_clnt.c
+++ b/ssl/statem/extensions_clnt.c
@@ -12,8 +12,8 @@
 #include "../ssl_locl.h"
 #include "statem_locl.h"
 
-int tls_construct_ctos_renegotiate(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
-                                   int *al)
+int tls_construct_ctos_renegotiate(SSL *s, WPACKET *pkt, X509 *x,
+                                   size_t chainidx, int *al)
 {
     /* Add RI if renegotiating */
     if (!s->renegotiate)
@@ -31,8 +31,8 @@ int tls_construct_ctos_renegotiate(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
     return 1;
 }
 
-int tls_construct_ctos_server_name(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
-                                   int *al)
+int tls_construct_ctos_server_name(SSL *s, WPACKET *pkt, X509 *x,
+                                   size_t chainidx, int *al)
 {
     if (s->tlsext_hostname == NULL)
         return 1;
@@ -56,7 +56,8 @@ int tls_construct_ctos_server_name(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
 }
 
 #ifndef OPENSSL_NO_SRP
-int tls_construct_ctos_srp(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_construct_ctos_srp(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
+                           int *al)
 {
     /* Add SRP username if there is one */
     if (s->srp_ctx.login == NULL)
@@ -108,7 +109,7 @@ static int use_ecc(SSL *s)
 }
 
 int tls_construct_ctos_ec_pt_formats(SSL *s, WPACKET *pkt, X509 *x,
-                                     size_t chain, int *al)
+                                     size_t chainidx, int *al)
 {
     const unsigned char *pformats;
     size_t num_formats;
@@ -132,7 +133,7 @@ int tls_construct_ctos_ec_pt_formats(SSL *s, WPACKET *pkt, X509 *x,
 }
 
 int tls_construct_ctos_supported_groups(SSL *s, WPACKET *pkt, X509 *x,
-                                        size_t chain, int *al)
+                                        size_t chainidx, int *al)
 {
     const unsigned char *pcurves = NULL, *pcurvestmp;
     size_t num_curves = 0, i;
@@ -182,7 +183,7 @@ int tls_construct_ctos_supported_groups(SSL *s, WPACKET *pkt, X509 *x,
 #endif
 
 int tls_construct_ctos_session_ticket(SSL *s, WPACKET *pkt, X509 *x,
-                                      size_t chain, int *al)
+                                      size_t chainidx, int *al)
 {
     size_t ticklen;
 
@@ -221,7 +222,7 @@ int tls_construct_ctos_session_ticket(SSL *s, WPACKET *pkt, X509 *x,
     return 1;
 }
 
-int tls_construct_ctos_sig_algs(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_ctos_sig_algs(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                                 int *al)
 {
     size_t salglen;
@@ -248,7 +249,7 @@ int tls_construct_ctos_sig_algs(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
 
 #ifndef OPENSSL_NO_OCSP
 int tls_construct_ctos_status_request(SSL *s, WPACKET *pkt, X509 *x,
-                                      size_t chain, int *al)
+                                      size_t chainidx, int *al)
 {
     int i;
 
@@ -314,7 +315,8 @@ int tls_construct_ctos_status_request(SSL *s, WPACKET *pkt, X509 *x,
 #endif
 
 #ifndef OPENSSL_NO_NEXTPROTONEG
-int tls_construct_ctos_npn(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_construct_ctos_npn(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
+                           int *al)
 {
     if (s->ctx->next_proto_select_cb == NULL || s->s3->tmp.finish_md_len != 0)
         return 1;
@@ -333,7 +335,7 @@ int tls_construct_ctos_npn(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al)
 }
 #endif
 
-int tls_construct_ctos_alpn(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_ctos_alpn(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                             int *al)
 {
     s->s3->alpn_sent = 0;
@@ -362,7 +364,7 @@ int tls_construct_ctos_alpn(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
 
 
 #ifndef OPENSSL_NO_SRTP
-int tls_construct_ctos_use_srtp(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_ctos_use_srtp(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                                 int *al)
 {
     STACK_OF(SRTP_PROTECTION_PROFILE) *clnt = SSL_get_srtp_profiles(s);
@@ -402,7 +404,8 @@ int tls_construct_ctos_use_srtp(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
 }
 #endif
 
-int tls_construct_ctos_etm(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_construct_ctos_etm(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
+                           int *al)
 {
     if (s->options & SSL_OP_NO_ENCRYPT_THEN_MAC)
         return 1;
@@ -417,7 +420,8 @@ int tls_construct_ctos_etm(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al)
 }
 
 #ifndef OPENSSL_NO_CT
-int tls_construct_ctos_sct(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_construct_ctos_sct(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
+                           int *al)
 {
     if (s->ct_validation_callback == NULL)
         return 1;
@@ -436,7 +440,8 @@ int tls_construct_ctos_sct(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al)
 }
 #endif
 
-int tls_construct_ctos_ems(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_construct_ctos_ems(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
+                           int *al)
 {
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_extended_master_secret)
             || !WPACKET_put_bytes_u16(pkt, 0)) {
@@ -448,7 +453,7 @@ int tls_construct_ctos_ems(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al)
 }
 
 int tls_construct_ctos_supported_versions(SSL *s, WPACKET *pkt, X509 *x,
-                                          size_t chain, int *al)
+                                          size_t chainidx, int *al)
 {
     int currv, min_version, max_version, reason;
 
@@ -494,7 +499,7 @@ int tls_construct_ctos_supported_versions(SSL *s, WPACKET *pkt, X509 *x,
     return 1;
 }
 
-int tls_construct_ctos_key_share(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_ctos_key_share(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                                  int *al)
 {
 #ifndef OPENSSL_NO_TLS1_3
@@ -585,7 +590,7 @@ int tls_construct_ctos_key_share(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
 #define F5_WORKAROUND_MIN_MSG_LEN   0xff
 #define F5_WORKAROUND_MAX_MSG_LEN   0x200
 
-int tls_construct_ctos_padding(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_ctos_padding(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                                int *al)
 {
     unsigned char *padbytes;
@@ -632,7 +637,7 @@ int tls_construct_ctos_padding(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
 /*
  * Parse the server's renegotiation binding and abort if it's not right
  */
-int tls_parse_stoc_renegotiate(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_stoc_renegotiate(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                int *al)
 {
     size_t expected_len = s->s3->previous_client_finished_len
@@ -690,7 +695,7 @@ int tls_parse_stoc_renegotiate(SSL *s, PACKET *pkt, X509 *x, size_t chain,
     return 1;
 }
 
-int tls_parse_stoc_server_name(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_stoc_server_name(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                int *al)
 {
     if (s->tlsext_hostname == NULL || PACKET_remaining(pkt) > 0) {
@@ -714,7 +719,7 @@ int tls_parse_stoc_server_name(SSL *s, PACKET *pkt, X509 *x, size_t chain,
 }
 
 #ifndef OPENSSL_NO_EC
-int tls_parse_stoc_ec_pt_formats(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_stoc_ec_pt_formats(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                  int *al)
 {
     unsigned int ecpointformatlist_length;
@@ -750,7 +755,7 @@ int tls_parse_stoc_ec_pt_formats(SSL *s, PACKET *pkt, X509 *x, size_t chain,
 }
 #endif
 
-int tls_parse_stoc_session_ticket(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_stoc_session_ticket(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                   int *al)
 {
     if (s->tls_session_ticket_ext_cb != NULL &&
@@ -772,7 +777,7 @@ int tls_parse_stoc_session_ticket(SSL *s, PACKET *pkt, X509 *x, size_t chain,
 }
 
 #ifndef OPENSSL_NO_OCSP
-int tls_parse_stoc_status_request(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_stoc_status_request(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                   int *al)
 {
     /*
@@ -789,7 +794,7 @@ int tls_parse_stoc_status_request(SSL *s, PACKET *pkt, X509 *x, size_t chain,
         /* We only know how to handle this if it's for the first Certificate in
          * the chain. We ignore any other repsonses.
          */
-        if (chain != 0)
+        if (chainidx != 0)
             return 1;
         return tls_process_cert_status_body(s, pkt, al);
     }
@@ -803,7 +808,7 @@ int tls_parse_stoc_status_request(SSL *s, PACKET *pkt, X509 *x, size_t chain,
 
 
 #ifndef OPENSSL_NO_CT
-int tls_parse_stoc_sct(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_parse_stoc_sct(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al)
 {
     /*
      * Only take it if we asked for it - i.e if there is no CT validation
@@ -856,7 +861,7 @@ static int ssl_next_proto_validate(PACKET *pkt)
     return 1;
 }
 
-int tls_parse_stoc_npn(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_parse_stoc_npn(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al)
 {
     unsigned char *selected;
     unsigned char selected_len;
@@ -906,7 +911,7 @@ int tls_parse_stoc_npn(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
 }
 #endif
 
-int tls_parse_stoc_alpn(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_parse_stoc_alpn(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al)
 {
     size_t len;
 
@@ -943,7 +948,8 @@ int tls_parse_stoc_alpn(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
 }
 
 #ifndef OPENSSL_NO_SRTP
-int tls_parse_stoc_use_srtp(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_parse_stoc_use_srtp(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
+                            int *al)
 {
     unsigned int id, ct, mki;
     int i;
@@ -996,7 +1002,7 @@ int tls_parse_stoc_use_srtp(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
 }
 #endif
 
-int tls_parse_stoc_etm(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_parse_stoc_etm(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al)
 {
     /* Ignore if inappropriate ciphersuite */
     if (!(s->options & SSL_OP_NO_ENCRYPT_THEN_MAC)
@@ -1007,7 +1013,7 @@ int tls_parse_stoc_etm(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
     return 1;
 }
 
-int tls_parse_stoc_ems(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_parse_stoc_ems(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al)
 {
     s->s3->flags |= TLS1_FLAGS_RECEIVED_EXTMS;
     if (!s->hit)
@@ -1016,7 +1022,7 @@ int tls_parse_stoc_ems(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
     return 1;
 }
 
-int tls_parse_stoc_key_share(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_stoc_key_share(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                              int *al)
 {
 #ifndef OPENSSL_NO_TLS1_3
diff --git a/ssl/statem/extensions_srvr.c b/ssl/statem/extensions_srvr.c
index f2fc979d34..dfe5fc5aca 100644
--- a/ssl/statem/extensions_srvr.c
+++ b/ssl/statem/extensions_srvr.c
@@ -14,7 +14,7 @@
 /*
  * Parse the client's renegotiation binding and abort if it's not right
  */
-int tls_parse_ctos_renegotiate(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_ctos_renegotiate(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                int *al)
 {
     unsigned int ilen;
@@ -73,7 +73,7 @@ int tls_parse_ctos_renegotiate(SSL *s, PACKET *pkt, X509 *x, size_t chain,
  *   extension.
  * - On session reconnect, the servername extension may be absent.
  */
-int tls_parse_ctos_server_name(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_ctos_server_name(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                int *al)
 {
     unsigned int servname_type;
@@ -136,7 +136,7 @@ int tls_parse_ctos_server_name(SSL *s, PACKET *pkt, X509 *x, size_t chain,
 }
 
 #ifndef OPENSSL_NO_SRP
-int tls_parse_ctos_srp(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_parse_ctos_srp(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al)
 {
     PACKET srp_I;
 
@@ -160,7 +160,7 @@ int tls_parse_ctos_srp(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
 #endif
 
 #ifndef OPENSSL_NO_EC
-int tls_parse_ctos_ec_pt_formats(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_ctos_ec_pt_formats(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                  int *al)
 {
     PACKET ec_point_format_list;
@@ -184,7 +184,7 @@ int tls_parse_ctos_ec_pt_formats(SSL *s, PACKET *pkt, X509 *x, size_t chain,
 }
 #endif                          /* OPENSSL_NO_EC */
 
-int tls_parse_ctos_session_ticket(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_ctos_session_ticket(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                   int *al)
 {
     if (s->tls_session_ticket_ext_cb &&
@@ -198,7 +198,8 @@ int tls_parse_ctos_session_ticket(SSL *s, PACKET *pkt, X509 *x, size_t chain,
     return 1;
 }
 
-int tls_parse_ctos_sig_algs(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_parse_ctos_sig_algs(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
+                            int *al)
 {
     PACKET supported_sig_algs;
 
@@ -219,7 +220,7 @@ int tls_parse_ctos_sig_algs(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
 }
 
 #ifndef OPENSSL_NO_OCSP
-int tls_parse_ctos_status_request(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_ctos_status_request(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                   int *al)
 {
     PACKET responder_id_list, exts;
@@ -318,7 +319,7 @@ int tls_parse_ctos_status_request(SSL *s, PACKET *pkt, X509 *x, size_t chain,
 #endif
 
 #ifndef OPENSSL_NO_NEXTPROTONEG
-int tls_parse_ctos_npn(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_parse_ctos_npn(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al)
 {
     /*
      * We shouldn't accept this extension on a
@@ -349,7 +350,7 @@ int tls_parse_ctos_npn(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
  * extension, not including type and length. |al| is a pointer to the alert
  * value to send in the event of a failure. Returns: 1 on success, 0 on error.
  */
-int tls_parse_ctos_alpn(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_parse_ctos_alpn(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al)
 {
     PACKET protocol_list, save_protocol_list, protocol;
 
@@ -382,7 +383,8 @@ int tls_parse_ctos_alpn(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
 }
 
 #ifndef OPENSSL_NO_SRTP
-int tls_parse_ctos_use_srtp(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_parse_ctos_use_srtp(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
+                            int *al)
 {
     STACK_OF(SRTP_PROTECTION_PROFILE) *srvr;
     unsigned int ct, mki_len, id;
@@ -452,7 +454,7 @@ int tls_parse_ctos_use_srtp(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
 }
 #endif
 
-int tls_parse_ctos_etm(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_parse_ctos_etm(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al)
 {
     if (!(s->options & SSL_OP_NO_ENCRYPT_THEN_MAC))
         s->s3->flags |= TLS1_FLAGS_ENCRYPT_THEN_MAC;
@@ -496,7 +498,7 @@ static int check_in_list(SSL *s, unsigned int group_id,
  * the raw PACKET data for the extension. Returns 1 on success or 0 on failure.
  * If a failure occurs then |*al| is set to an appropriate alert value.
  */
-int tls_parse_ctos_key_share(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_ctos_key_share(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                              int *al)
 {
 #ifndef OPENSSL_NO_TLS1_3
@@ -626,8 +628,8 @@ int tls_parse_ctos_key_share(SSL *s, PACKET *pkt, X509 *x, size_t chain,
 }
 
 #ifndef OPENSSL_NO_EC
-int tls_parse_ctos_supported_groups(SSL *s, PACKET *pkt, X509 *x, size_t chain,
-                                    int *al)
+int tls_parse_ctos_supported_groups(SSL *s, PACKET *pkt, X509 *x,
+                                    size_t chainidx, int *al)
 {
     PACKET supported_groups_list;
 
@@ -651,7 +653,7 @@ int tls_parse_ctos_supported_groups(SSL *s, PACKET *pkt, X509 *x, size_t chain,
 }
 #endif
 
-int tls_parse_ctos_ems(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_parse_ctos_ems(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al)
 {
     /* The extension must always be empty */
     if (PACKET_remaining(pkt) != 0) {
@@ -667,8 +669,8 @@ int tls_parse_ctos_ems(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al)
 /*
  * Add the server's renegotiation binding
  */
-int tls_construct_stoc_renegotiate(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
-                                   int *al)
+int tls_construct_stoc_renegotiate(SSL *s, WPACKET *pkt, X509 *x, size_t
+                                   chainidx, int *al)
 {
     if (!s->s3->send_connection_binding)
         return 1;
@@ -689,8 +691,8 @@ int tls_construct_stoc_renegotiate(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
     return 1;
 }
 
-int tls_construct_stoc_server_name(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
-                                   int *al)
+int tls_construct_stoc_server_name(SSL *s, WPACKET *pkt, X509 *x,
+                                   size_t chainidx, int *al)
 {
     if (s->hit || s->servername_done != 1
             || s->session->tlsext_hostname == NULL)
@@ -707,7 +709,7 @@ int tls_construct_stoc_server_name(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
 
 #ifndef OPENSSL_NO_EC
 int tls_construct_stoc_ec_pt_formats(SSL *s, WPACKET *pkt, X509 *x,
-                                     size_t chain, int *al)
+                                     size_t chainidx, int *al)
 {
     unsigned long alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
     unsigned long alg_a = s->s3->tmp.new_cipher->algorithm_auth;
@@ -733,7 +735,7 @@ int tls_construct_stoc_ec_pt_formats(SSL *s, WPACKET *pkt, X509 *x,
 #endif
 
 int tls_construct_stoc_session_ticket(SSL *s, WPACKET *pkt, X509 *x,
-                                      size_t chain, int *al)
+                                      size_t chainidx, int *al)
 {
     if (!s->tlsext_ticket_expected || !tls_use_ticket(s)) {
         s->tlsext_ticket_expected = 0;
@@ -751,12 +753,12 @@ int tls_construct_stoc_session_ticket(SSL *s, WPACKET *pkt, X509 *x,
 
 #ifndef OPENSSL_NO_OCSP
 int tls_construct_stoc_status_request(SSL *s, WPACKET *pkt, X509 *x,
-                                     size_t chain, int *al)
+                                     size_t chainidx, int *al)
 {
     if (!s->tlsext_status_expected)
         return 1;
 
-    if (SSL_IS_TLS13(s) && chain != 0)
+    if (SSL_IS_TLS13(s) && chainidx != 0)
         return 1;
 
     if (!WPACKET_put_bytes_u16(pkt, TLSEXT_TYPE_status_request)
@@ -782,7 +784,7 @@ int tls_construct_stoc_status_request(SSL *s, WPACKET *pkt, X509 *x,
 
 #ifndef OPENSSL_NO_NEXTPROTONEG
 int tls_construct_stoc_next_proto_neg(SSL *s, WPACKET *pkt, X509 *x,
-                                      size_t chain, int *al)
+                                      size_t chainidx, int *al)
 {
     const unsigned char *npa;
     unsigned int npalen;
@@ -809,7 +811,7 @@ int tls_construct_stoc_next_proto_neg(SSL *s, WPACKET *pkt, X509 *x,
 }
 #endif
 
-int tls_construct_stoc_alpn(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_stoc_alpn(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                             int *al)
 {
     if (s->s3->alpn_selected == NULL)
@@ -831,7 +833,7 @@ int tls_construct_stoc_alpn(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
 }
 
 #ifndef OPENSSL_NO_SRTP
-int tls_construct_stoc_use_srtp(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_stoc_use_srtp(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                                 int *al)
 {
     if (s->srtp_profile == NULL)
@@ -851,7 +853,8 @@ int tls_construct_stoc_use_srtp(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
 }
 #endif
 
-int tls_construct_stoc_etm(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_construct_stoc_etm(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
+                           int *al)
 {
     if ((s->s3->flags & TLS1_FLAGS_ENCRYPT_THEN_MAC) == 0)
         return 1;
@@ -877,7 +880,8 @@ int tls_construct_stoc_etm(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al)
     return 1;
 }
 
-int tls_construct_stoc_ems(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al)
+int tls_construct_stoc_ems(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
+                           int *al)
 {
     if ((s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) == 0)
         return 1;
@@ -891,7 +895,7 @@ int tls_construct_stoc_ems(SSL *s, WPACKET *pkt, X509 *x, size_t chain, int *al)
     return 1;
 }
 
-int tls_construct_stoc_key_share(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_stoc_key_share(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                                  int *al)
 {
 #ifndef OPENSSL_NO_TLS1_3
@@ -949,7 +953,7 @@ int tls_construct_stoc_key_share(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
 }
 
 int tls_construct_stoc_cryptopro_bug(SSL *s, WPACKET *pkt, X509 *x,
-                                     size_t chain, int *al)
+                                     size_t chainidx, int *al)
 {
     const unsigned char cryptopro_ext[36] = {
         0xfd, 0xe8,         /* 65000 */
diff --git a/ssl/statem/statem_locl.h b/ssl/statem/statem_locl.h
index 35115c9e93..7da975473c 100644
--- a/ssl/statem/statem_locl.h
+++ b/ssl/statem/statem_locl.h
@@ -158,77 +158,77 @@ __owur int tls_construct_new_session_ticket(SSL *s, WPACKET *pkt);
 __owur int tls_collect_extensions(SSL *s, PACKET *packet, unsigned int context,
                                   RAW_EXTENSION **res, int *al);
 __owur int tls_parse_extension(SSL *s, TLSEXT_INDEX idx, int context,
-                               RAW_EXTENSION *exts,  X509 *x, size_t chain,
+                               RAW_EXTENSION *exts,  X509 *x, size_t chainidx,
                                int *al);
 __owur int tls_parse_all_extensions(SSL *s, int context, RAW_EXTENSION *exts,
-                                    X509 *x, size_t chain, int *al);
+                                    X509 *x, size_t chainidx, int *al);
 __owur int tls_construct_extensions(SSL *s, WPACKET *pkt, unsigned int context,
-                                    X509 *x, size_t chain, int *al);
+                                    X509 *x, size_t chainidx, int *al);
 
 /* Server Extension processing */
-int tls_parse_ctos_renegotiate(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_ctos_renegotiate(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                int *al);
-int tls_parse_ctos_server_name(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_ctos_server_name(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                int *al);
 #ifndef OPENSSL_NO_SRP
-int tls_parse_ctos_srp(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al);
+int tls_parse_ctos_srp(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al);
 #endif
 #ifndef OPENSSL_NO_EC
-int tls_parse_ctos_ec_pt_formats(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_ctos_ec_pt_formats(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                  int *al);
-int tls_parse_ctos_supported_groups(SSL *s, PACKET *pkt, X509 *x, size_t chain,
-                                    int *al);
+int tls_parse_ctos_supported_groups(SSL *s, PACKET *pkt, X509 *x,
+                                    size_t chainidx, int *al);
 #endif
-int tls_parse_ctos_session_ticket(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_ctos_session_ticket(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                   int *al);
-int tls_parse_ctos_sig_algs(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_ctos_sig_algs(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                             int *al);
 #ifndef OPENSSL_NO_OCSP
-int tls_parse_ctos_status_request(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_ctos_status_request(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                                   int *al);
 #endif
 #ifndef OPENSSL_NO_NEXTPROTONEG
-int tls_parse_ctos_npn(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al);
+int tls_parse_ctos_npn(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al);
 #endif
-int tls_parse_ctos_alpn(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al);
+int tls_parse_ctos_alpn(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al);
 #ifndef OPENSSL_NO_SRTP
-int tls_parse_ctos_use_srtp(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_ctos_use_srtp(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                             int *al);
 #endif
-int tls_parse_ctos_etm(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al);
-int tls_parse_ctos_key_share(SSL *s, PACKET *pkt, X509 *x, size_t chain,
+int tls_parse_ctos_etm(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al);
+int tls_parse_ctos_key_share(SSL *s, PACKET *pkt, X509 *x, size_t chainidx,
                              int *al);
-int tls_parse_ctos_ems(SSL *s, PACKET *pkt, X509 *x, size_t chain, int *al);
+int tls_parse_ctos_ems(SSL *s, PACKET *pkt, X509 *x, size_t chainidx, int *al);
 
-int tls_construct_stoc_renegotiate(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
-                                   int *al);
-int tls_construct_stoc_server_name(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
-                                   int *al);
+int tls_construct_stoc_renegotiate(SSL *s, WPACKET *pkt, X509 *x,
+                                   size_t chainidx, int *al);
+int tls_construct_stoc_server_name(SSL *s, WPACKET *pkt, X509 *x,
+                                   size_t chainidx, int *al);
 #ifndef OPENSSL_NO_EC
 int tls_construct_stoc_ec_pt_formats(SSL *s, WPACKET *pkt, X509 *x,
-                                     size_t chain, int *al);
+                                     size_t chainidx, int *al);
 #endif
 int tls_construct_stoc_session_ticket(SSL *s, WPACKET *pkt, X509 *x,
-                                      size_t chain, int *al);
+                                      size_t chainidx, int *al);
 #ifndef OPENSSL_NO_OCSP
 int tls_construct_stoc_status_request(SSL *s, WPACKET *pkt, X509 *x,
-                                      size_t chain, int *al);
+                                      size_t chainidx, int *al);
 #endif
 #ifndef OPENSSL_NO_NEXTPROTONEG
 int tls_construct_stoc_next_proto_neg(SSL *s, WPACKET *pkt, X509 *x,
-                                      size_t chain, int *al);
+                                      size_t chainidx, int *al);
 #endif
-int tls_construct_stoc_alpn(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_stoc_alpn(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                             int *al);
 #ifndef OPENSSL_NO_SRTP
-int tls_construct_stoc_use_srtp(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_stoc_use_srtp(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                                 int *al);
 #endif
-int tls_construct_stoc_etm(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_stoc_etm(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                            int *al);
-int tls_construct_stoc_ems(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_stoc_ems(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                            int *al);
-int tls_construct_stoc_key_share(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_stoc_key_share(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                                  int *al);
 /*
  * Not in public headers as this is not an official extension. Only used when
@@ -236,81 +236,81 @@ int tls_construct_stoc_key_share(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
  */
 #define TLSEXT_TYPE_cryptopro_bug      0xfde8
 int tls_construct_stoc_cryptopro_bug(SSL *s, WPACKET *pkt, X509 *x,
-                                     size_t chain, int *al);
+                                     size_t chainidx, int *al);
 
 /* Client Extension processing */
-int tls_construct_ctos_renegotiate(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
-                                   int *al);
-int tls_construct_ctos_server_name(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
-                                   int *al);
+int tls_construct_ctos_renegotiate(SSL *s, WPACKET *pkt, X509 *x,
+                                   size_t chainidx, int *al);
+int tls_construct_ctos_server_name(SSL *s, WPACKET *pkt, X509 *x,
+                                   size_t chainidx, int *al);
 #ifndef OPENSSL_NO_SRP
-int tls_construct_ctos_srp(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_ctos_srp(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                                    int *al);
 #endif
 #ifndef OPENSSL_NO_EC
 int tls_construct_ctos_ec_pt_formats(SSL *s, WPACKET *pkt, X509 *x,
-                                     size_t chain, int *al);
+                                     size_t chainidx, int *al);
 int tls_construct_ctos_supported_groups(SSL *s, WPACKET *pkt, X509 *x,
-                                        size_t chain, int *al);
+                                        size_t chainidx, int *al);
 #endif
 int tls_construct_ctos_session_ticket(SSL *s, WPACKET *pkt, X509 *x,
-                                      size_t chain, int *al);
-int tls_construct_ctos_sig_algs(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+                                      size_t chainidx, int *al);
+int tls_construct_ctos_sig_algs(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                                 int *al);
 #ifndef OPENSSL_NO_OCSP
 int tls_construct_ctos_status_request(SSL *s, WPACKET *pkt, X509 *x,
-                                      size_t chain, int *al);
+                                      size_t chainidx, int *al);
 #endif
 #ifndef OPENSSL_NO_NEXTPROTONEG
-int tls_construct_ctos_npn(SSL *s, WPACKET *pkt, X509 *x, size_t chain,
+int tls_construct_ctos_npn(SSL *s, WPACKET *pkt, X509 *x, size_t chainidx,
                            int *al);
 #endif
-int tl