From 77a97536e8878ff0ddcd08cde16e9e54a9c226e1 Mon Sep 17 00:00:00 2001
From: William Lallemand <wlallemand@haproxy.com>
Date: Thu, 23 Nov 2023 17:54:47 +0100
Subject: [PATCH] MEDIUM: ssl: use ssl_sock_chose_sni_ctx() in the clienthello
 callback

This patch removes the code which selects the SSL certificate in the
OpenSSL Client Hello callback, to use the ssl_sock_chose_sni_ctx()
function which does the same.

The bigger part of the function which remains is the extraction of the
servername, ciphers and sigalgs, because it's done manually by parsing
the TLS extensions.

This is not supposed to change anything functionally.
---
 src/ssl_sock.c | 79 +++++---------------------------------------------
 1 file changed, 7 insertions(+), 72 deletions(-)

diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index 5219f3e2b..99a72d33d 100644
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -2435,11 +2435,9 @@ int ssl_sock_switchctx_cbk(SSL *ssl, int *al, void *arg)
 	const uint8_t *extension_data;
 	size_t extension_len;
 	int has_rsa_sig = 0, has_ecdsa_sig = 0;
-
-	char *wildp = NULL;
+	struct sni_ctx *sni_ctx;
 	const char *servername;
 	size_t servername_len;
-	struct ebmb_node *node, *n, *node_ecdsa = NULL, *node_rsa = NULL, *node_anonymous = NULL;
 	int allow_early = 0;
 	int i;
 
@@ -2610,81 +2608,18 @@ int ssl_sock_switchctx_cbk(SSL *ssl, int *al, void *arg)
 		}
 	}
 
-	for (i = 0; i < trash.size && i < servername_len; i++) {
+	/* we need to transform this a NULL-ended string in lowecase */
+	for (i = 0; i < trash.size && i < servername_len; i++)
 		trash.area[i] = tolower(servername[i]);
-		if (!wildp && (trash.area[i] == '.'))
-			wildp = &trash.area[i];
-	}
 	trash.area[i] = 0;
 	servername = trash.area;
 
 	HA_RWLOCK_RDLOCK(SNI_LOCK, &s->sni_lock);
-
-	/* Look for an ECDSA, RSA and DSA certificate, first in the single
-	 * name and if not found in the wildcard  */
-	for (i = 0; i < 2; i++) {
-		if (i == 0) 	/* lookup in full qualified names */
-			node = ebst_lookup(&s->sni_ctx, servername);
-		else if (i == 1 && wildp)  /* lookup in wildcards names */
-			node = ebst_lookup(&s->sni_w_ctx, wildp);
-		else
-			break;
-
-		for (n = node; n; n = ebmb_next_dup(n)) {
-
-			/* lookup a not neg filter */
-			if (!container_of(n, struct sni_ctx, name)->neg) {
-				struct sni_ctx *sni, *sni_tmp;
-				int skip = 0;
-
-				if (i == 1 && wildp) { /* wildcard */
-					/* If this is a wildcard, look for an exclusion on the same crt-list line */
-					sni = container_of(n, struct sni_ctx, name);
-					list_for_each_entry(sni_tmp, &sni->ckch_inst->sni_ctx, by_ckch_inst) {
-						if (sni_tmp->neg && (strcmp((const char *)sni_tmp->name.key, servername) == 0)) {
-							skip = 1;
-							break;
-						}
-					}
-					if (skip)
-						continue;
-				}
-
-				switch(container_of(n, struct sni_ctx, name)->kinfo.sig) {
-				case TLSEXT_signature_ecdsa:
-					if (!node_ecdsa)
-						node_ecdsa = n;
-					break;
-				case TLSEXT_signature_rsa:
-					if (!node_rsa)
-						node_rsa = n;
-					break;
-				default: /* TLSEXT_signature_anonymous|dsa */
-					if (!node_anonymous)
-						node_anonymous = n;
-					break;
-				}
-			}
-		}
-	}
-	/* Once the certificates are found, select them depending on what is
-	 * supported in the client and by key_signature priority order: EDSA >
-	 * RSA > DSA */
-	if (has_ecdsa_sig && node_ecdsa)
-		node = node_ecdsa;
-	else if (has_rsa_sig && node_rsa)
-		node = node_rsa;
-	else if (node_anonymous)
-		node = node_anonymous;
-	else if (node_ecdsa)
-		node = node_ecdsa;      /* no ecdsa signature case (< TLSv1.2) */
-	else
-		node = node_rsa;        /* no rsa signature case (far far away) */
-
-	if (node) {
+	sni_ctx = ssl_sock_chose_sni_ctx(s, servername, has_rsa_sig, has_ecdsa_sig);
+	if (sni_ctx) {
 		/* switch ctx */
-		struct ssl_bind_conf *conf = container_of(node, struct sni_ctx, name)->conf;
-		ssl_sock_switchctx_set(ssl, container_of(node, struct sni_ctx, name)->ctx);
+		struct ssl_bind_conf *conf = sni_ctx->conf;
+		ssl_sock_switchctx_set(ssl, sni_ctx->ctx);
 		if (conf) {
 			methodVersions[conf->ssl_methods.min].ssl_set_version(ssl, SET_MIN);
 			methodVersions[conf->ssl_methods.max].ssl_set_version(ssl, SET_MAX);