BUG/MEDIUM: ssl: initialize correctly ssl w/ default-server

This bug was introduced by d817dc73 ("MEDIUM: ssl: Load client
certificates in a ckch for backend servers") in which the creation of
the SSL_CTX for a server was moved to the configuration parser when
using a "crt" keyword instead of being done in ssl_sock_prepare_srv_ctx().

The patch 0498fa40 ("BUG/MINOR: ssl: Default-server configuration ignored by
server") made it worse by setting the same SSL_CTX for every servers
using a default-server. Resulting in any SSL option on a server applied
to every server in its backend.

This patch fixes the issue by reintroducing a string which store the
path of certificate inside the server structure, and loading the
certificate in ssl_sock_prepare_srv_ctx() again.

This is a quick fix to backport, a cleaner way can be achieve by always
creating the SSL_CTX in ssl_sock_prepare_srv_ctx() and splitting
properly the ssl_sock_load_srv_cert() function.

This patch fixes issue #1488.

Must be backported as far as 2.4.

include/haproxy/server-t.h

@@ -357,6 +357,7 @@ struct server {
 		char *verify_host;              /* hostname of certificate must match this host */
 		char *ca_file;			/* CAfile to use on verify */
 		char *crl_file;			/* CRLfile to use on verify */
+		char *client_crt;		/* client certificate to send */
 		struct sample_expr *sni;        /* sample expression for SNI */
 		char *npn_str;                  /* NPN protocol string */
 		int npn_len;                    /* NPN protocol string length */

reg-tests/ssl/ssl_default_server.vtc

@@ -15,7 +15,7 @@ feature cmd "$HAPROXY_PROGRAM -cc 'version_atleast(2.5-dev0)'"
 feature cmd "$HAPROXY_PROGRAM -cc 'feature(OPENSSL)'"
 feature ignore_unknown_macro
 
-server s1 -repeat 7 {
+server s1 -repeat 10 {
   rxreq
   txresp
 } -start
@@ -56,7 +56,10 @@ haproxy h1 -conf {
 
     backend third_be
         default-server ssl crt client1.pem ca-file ca-auth.crt verify none
-        server s1 "${tmpdir}/ssl.sock" crt client2_expired.pem
+        server s1 "${tmpdir}/ssl.sock"
+        server s2 "${tmpdir}/ssl.sock" crt client2_expired.pem
+        server s3 "${tmpdir}/ssl.sock"
+        server s4 "${tmpdir}/ssl.sock"
 
     backend fourth_be
         default-server ssl crt client1.pem verify none
@@ -101,6 +104,14 @@ client c1 -connect ${h1_clearlst_sock} {
     expect resp.http.x-ssl == "Ok"
 } -run
 
+client c1 -connect ${h1_clearlst_sock} {
+    txreq -url "/third"
+    txreq
+    rxresp
+    expect resp.status == 200
+    expect resp.http.x-ssl == "Ok"
+} -run
+
 client c1 -connect ${h1_clearlst_sock} {
     txreq -url "/third"
     txreq
@@ -109,6 +120,14 @@ client c1 -connect ${h1_clearlst_sock} {
     expect resp.http.x-ssl == "Expired"
 } -run
 
+client c1 -connect ${h1_clearlst_sock} -repeat 2 {
+    txreq -url "/third"
+    txreq
+    rxresp
+    expect resp.status == 200
+    expect resp.http.x-ssl == "Ok"
+} -run
+
 client c1 -connect ${h1_clearlst_sock} {
     txreq -url "/fourth"
     txreq

src/cfgparse-ssl.c

@@ -1500,9 +1500,6 @@ static int srv_parse_crl_file(char **args, int *cur_arg, struct proxy *px, struc
 /* parse the "crt" server keyword */
 static int srv_parse_crt(char **args, int *cur_arg, struct proxy *px, struct server *newsrv, char **err)
 {
-	const int create_if_none = newsrv->flags & SRV_F_DYNAMIC ? 0 : 1;
-	int retval = -1;
-	char *path = NULL;
 
 	if (!*args[*cur_arg + 1]) {
 		memprintf(err, "'%s' : missing certificate file path", args[*cur_arg]);
@@ -1510,16 +1507,11 @@ static int srv_parse_crt(char **args, int *cur_arg, struct proxy *px, struct ser
 	}
 
 	if ((*args[*cur_arg + 1] != '/') && global_ssl.crt_base)
-		memprintf(&path, "%s/%s", global_ssl.crt_base, args[*cur_arg + 1]);
+		memprintf(&newsrv->ssl_ctx.client_crt, "%s/%s", global_ssl.crt_base, args[*cur_arg + 1]);
 	else
-		memprintf(&path, "%s", args[*cur_arg + 1]);
+		memprintf(&newsrv->ssl_ctx.client_crt, "%s", args[*cur_arg + 1]);
 
-	if (path) {
-		retval = ssl_sock_load_srv_cert(path, newsrv, create_if_none, err);
-		free(path);
-	}
-
-	return retval;
+	return 0;
 }
 
 /* parse the "no-check-ssl" server keyword */

src/server.c

@@ -2050,6 +2050,8 @@ static void srv_conn_src_cpy(struct server *srv, struct server *src)
 static void srv_ssl_settings_cpy(struct server *srv, struct server *src)
 {
 	/* <src> is the current proxy's default server and SSL is enabled */
+	BUG_ON(src->ssl_ctx.ctx != NULL); /* the SSL_CTX must never be initialized in a default-server */
+
 	if (src == &srv->proxy->defsrv && src->use_ssl == 1)
 		srv->flags |= SRV_F_DEFSRV_USE_SSL;
 
@@ -2057,10 +2059,11 @@ static void srv_ssl_settings_cpy(struct server *srv, struct server *src)
 		srv->ssl_ctx.ca_file = strdup(src->ssl_ctx.ca_file);
 	if (src->ssl_ctx.crl_file != NULL)
 		srv->ssl_ctx.crl_file = strdup(src->ssl_ctx.crl_file);
+	if (src->ssl_ctx.client_crt != NULL)
+		srv->ssl_ctx.client_crt = strdup(src->ssl_ctx.client_crt);
 
 	srv->ssl_ctx.verify = src->ssl_ctx.verify;
 
-	srv->ssl_ctx.ctx = src->ssl_ctx.ctx;
 
 	if (src->ssl_ctx.verify_host != NULL)
 		srv->ssl_ctx.verify_host = strdup(src->ssl_ctx.verify_host);

src/ssl_sock.c

@@ -4837,8 +4837,7 @@ static int ssl_sock_srv_verifycbk(int ok, X509_STORE_CTX *ctx)
 int ssl_sock_prepare_srv_ctx(struct server *srv)
 {
 	int cfgerr = 0;
-	SSL_CTX *ctx = srv->ssl_ctx.ctx;
-
+	SSL_CTX *ctx;
 	/* Automatic memory computations need to know we use SSL there */
 	global.ssl_used_backend = 1;
 
@@ -4853,6 +4852,27 @@ int ssl_sock_prepare_srv_ctx(struct server *srv)
 	if (srv->use_ssl == 1)
 		srv->xprt = &ssl_sock;
 
+	if (srv->ssl_ctx.client_crt) {
+		const int create_if_none = srv->flags & SRV_F_DYNAMIC ? 0 : 1;
+		char *err = NULL;
+		int err_code = 0;
+
+		/* If there is a crt keyword there, the SSL_CTX will be created here. */
+		err_code = ssl_sock_load_srv_cert(srv->ssl_ctx.client_crt, srv, create_if_none, &err);
+		if (err_code != ERR_NONE) {
+			if ((err_code & ERR_WARN) && !(err_code & ERR_ALERT))
+				ha_warning("%s", err);
+			else
+				ha_alert("%s", err);
+
+			if (err_code & (ERR_FATAL|ERR_ABORT))
+				cfgerr++;
+		}
+		ha_free(&err);
+	}
+
+	ctx = srv->ssl_ctx.ctx;
+
 	/* The context will be uninitialized if there wasn't any "cert" option
 	 * in the server line. */
 	if (!ctx) {