MINOR: ssl: allow to change the server signature algorithm

This patch introduces the "sigalgs" keyword for the bind line, which
allows to configure the list of server signature algorithms negociated
during the handshake. Also available as "ssl-default-bind-sigalgs" in
the default section.

This patch was originally written by Bruno Henc.

diff --git a/doc/configuration.txt b/doc/configuration.txt
index 9d4aa3c24793d987c6f338c1691bda9dee11cefd..0111b6125aa8fe61c6f5c3025b26589a31f15495 100644 (file)
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -1097,6 +1097,7 @@ The following keywords are supported in the "global" section :
    - ssl-default-bind-ciphersuites
    - ssl-default-bind-curves
    - ssl-default-bind-options
+   - ssl-default-bind-sigalgs
    - ssl-default-server-ciphers
    - ssl-default-server-ciphersuites
    - ssl-default-server-options
@@ -2183,6 +2184,22 @@ ssl-default-bind-options [<option>]...
         global
            ssl-default-bind-options ssl-min-ver TLSv1.0 no-tls-tickets
 
+ssl-default-bind-sigalgs <sigalgs>
+  This setting is only available when support for OpenSSL was built in. It
+  sets the default string describing the list of signature algorithms that
+  are negotiated during the TLSv1.2 and TLSv1.3 handshake for all "bind" lines
+  which do not explicitly define theirs. The format of the string is a
+  colon-delimited list of signature algorithms. Each signature algorithm can
+  use one of two forms: TLS1.3 signature scheme names ("rsa_pss_rsae_sha256")
+  or the public key algorithm + digest form ("ECDSA+SHA256"). A list
+  can contain both forms. For more information on the format,
+  see SSL_CTX_set1_sigalgs(3). A list of signature algorithms is also
+  available in RFC8446 section 4.2.3 and in OpenSSL in the ssl/t1_lib.c file.
+  This setting is not applicable to TLSv1.1 and earlier versions of the
+  protocol as the signature algorithms aren't separately negotiated in these
+  versions. It is not recommended to change this setting unless compatibility
+  with a middlebox is required.
+
 ssl-default-server-ciphers <ciphers>
   This setting is only available when support for OpenSSL was built in. It
   sets the default string describing the list of cipher algorithms that are
@@ -15330,6 +15347,14 @@ shards <number> | by-thread | by-group
   warning will be emitted if this happens since the resulting number of
   listeners will not be the expected one.
 
+sigalgs <sigalgs>
+  This setting is only available when support for OpenSSL was built in. It sets
+  the string describing the list of signature algorithms that are negotiated
+  during the TLSv1.2 and TLSv1.3 handshake. The format of the string is defined
+  in "man 3 SSL_CTX_set1_sigalgs" from the OpenSSL man pages. It is not
+  recommended to use this setting unless compatibility with a middlebox is
+  required.
+
 ssl
   This setting is only available when support for OpenSSL was built in. It
   enables SSL deciphering on connections instantiated from this listener. A

diff --git a/include/haproxy/listener-t.h b/include/haproxy/listener-t.h
index 92aa9cf5f3a88690b8c1ae67e884952a373c5625..ff5b30da720f281abbd1932078667a296f92276f 100644 (file)
--- a/include/haproxy/listener-t.h
+++ b/include/haproxy/listener-t.h
@@ -143,6 +143,7 @@ struct ssl_bind_conf {
        char *ciphersuites;        /* TLS 1.3 cipher suite to use if non-null */
        char *curves;              /* curves suite to use for ECDHE */
        char *ecdhe;               /* named curve to use for ECDHE */
+       char *sigalgs;             /* Signature algorithms */
        struct tls_version_filter ssl_methods_cfg; /* original ssl methods found in configuration */
        struct tls_version_filter ssl_methods; /* actual ssl methods used at runtime */
 #endif

diff --git a/include/haproxy/openssl-compat.h b/include/haproxy/openssl-compat.h
index d1fa7baac5d514c115e99d2e18ae7bc324c15d4f..b857e108c168bbd02186de48f98fe1c989f39d46 100644 (file)
--- a/include/haproxy/openssl-compat.h
+++ b/include/haproxy/openssl-compat.h
@@ -520,5 +520,9 @@ static inline unsigned long ERR_peek_error_func(const char **func)
 #define SSL_CTX_set1_curves_list SSL_CTX_set1_curves_list
 #endif
 
+#if !defined(SSL_CTX_set1_sigalgs_list) && defined(SSL_CTRL_SET_SIGALGS_LIST)
+#define SSL_CTX_set1_sigalgs_list SSL_CTX_set1_sigalgs_list
+#endif
+
 #endif /* USE_OPENSSL */
 #endif /* _HAPROXY_OPENSSL_COMPAT_H */

diff --git a/include/haproxy/ssl_sock-t.h b/include/haproxy/ssl_sock-t.h
index 022c5748711536adc1f1ba6fe823093739284a8d..b4d350215e7245a04f2bb627d4630268b6ecaab4 100644 (file)
--- a/include/haproxy/ssl_sock-t.h
+++ b/include/haproxy/ssl_sock-t.h
@@ -278,6 +278,9 @@ struct global_ssl {
 #endif
 #if defined(SSL_CTX_set1_curves_list)
        char *listen_default_curves;
+#endif
+#if defined(SSL_CTX_set1_sigalgs_list)
+       char *listen_default_sigalgs;
 #endif
        int listen_default_ssloptions;
        int connect_default_ssloptions;

diff --git a/src/cfgparse-ssl.c b/src/cfgparse-ssl.c
index 43ac3dfdc87d3296748d051362dba32d3e033592..48e14508902d672e61de550b955d7185fd5dae5b 100644 (file)
--- a/src/cfgparse-ssl.c
+++ b/src/cfgparse-ssl.c
@@ -316,6 +316,34 @@ static int ssl_parse_global_curves(char **args, int section_type, struct proxy *
        return 0;
 }
 #endif
+
+#if defined(SSL_CTX_set1_sigalgs_list)
+/*
+ * parse the "ssl-default-bind-sigalgs" keyword in a global section.
+ * Returns <0 on alert, >0 on warning, 0 on success.
+ */
+static int ssl_parse_global_sigalgs(char **args, int section_type, struct proxy *curpx,
+                                   const struct proxy *defpx, const char *file, int line,
+                                  char **err)
+{
+       char **target;
+
+       target = &global_ssl.listen_default_sigalgs;
+
+       if (too_many_args(1, args, err, NULL))
+               return -1;
+
+       if (*(args[1]) == 0) {
+               memprintf(err, "global statement '%s' expects a curves suite as an arguments.", args[0]);
+               return -1;
+       }
+
+       free(*target);
+       *target = strdup(args[1]);
+       return 0;
+}
+#endif
+
 /* parse various global tune.ssl settings consisting in positive integers.
  * Returns <0 on alert, >0 on warning, 0 on success.
  */
@@ -798,6 +826,27 @@ static int bind_parse_curves(char **args, int cur_arg, struct proxy *px, struct
        return ssl_bind_parse_curves(args, cur_arg, px, &conf->ssl_conf, 0, err);
 }
 
+/* parse the "sigalgs" bind keyword */
+static int ssl_bind_parse_sigalgs(char **args, int cur_arg, struct proxy *px, struct ssl_bind_conf *conf, int from_cli, char **err)
+{
+#if defined(SSL_CTX_set1_sigalgs_list)
+       if (!*args[cur_arg + 1]) {
+               memprintf(err, "'%s' : missing signature algorithm list", args[cur_arg]);
+               return ERR_ALERT | ERR_FATAL;
+       }
+       conf->sigalgs = strdup(args[cur_arg + 1]);
+       return 0;
+#else
+       memprintf(err, "'%s' : library does not support setting signature algorithms", args[cur_arg]);
+       return ERR_ALERT | ERR_FATAL;
+#endif
+}
+static int bind_parse_sigalgs(char **args, int cur_arg, struct proxy *px, struct bind_conf *conf, char **err)
+{
+       return ssl_bind_parse_sigalgs(args, cur_arg, px, &conf->ssl_conf, 0, err);
+}
+
+
 /* parse the "ecdhe" bind keyword keyword */
 static int ssl_bind_parse_ecdhe(char **args, int cur_arg, struct proxy *px, struct ssl_bind_conf *conf, int from_cli, char **err)
 {
@@ -1153,6 +1202,10 @@ static int bind_parse_ssl(char **args, int cur_arg, struct proxy *px, struct bin
        if (global_ssl.listen_default_curves && !conf->ssl_conf.curves)
                conf->ssl_conf.curves = strdup(global_ssl.listen_default_curves);
 #endif
+#if defined(SSL_CTX_set1_sigalgs_list)
+       if (global_ssl.listen_default_sigalgs && !conf->ssl_conf.sigalgs)
+               conf->ssl_conf.sigalgs = strdup(global_ssl.listen_default_sigalgs);
+#endif
 #ifdef HAVE_SSL_CTX_SET_CIPHERSUITES
        if (global_ssl.listen_default_ciphersuites && !conf->ssl_conf.ciphersuites)
                conf->ssl_conf.ciphersuites = strdup(global_ssl.listen_default_ciphersuites);
@@ -2009,6 +2062,7 @@ struct ssl_crtlist_kw ssl_crtlist_kws[] = {
        { "no-alpn",               ssl_bind_parse_no_alpn,          0 }, /* disable sending ALPN */
        { "no-ca-names",           ssl_bind_parse_no_ca_names,      0 }, /* do not send ca names to clients (ca_file related) */
        { "npn",                   ssl_bind_parse_npn,              1 }, /* set NPN supported protocols */
+       { "sigalgs",               ssl_bind_parse_sigalgs,          1 }, /* set SSL signature algorithms */
        { "ssl-min-ver",           ssl_bind_parse_tls_method_minmax,1 }, /* minimum version */
        { "ssl-max-ver",           ssl_bind_parse_tls_method_minmax,1 }, /* maximum version */
        { "verify",                ssl_bind_parse_verify,           1 }, /* set SSL verify method */
@@ -2050,6 +2104,7 @@ static struct bind_kw_list bind_kws = { "SSL", { }, {
        { "no-tlsv12",             bind_parse_tls_method_options, 0 }, /* disable TLSv12 */
        { "no-tlsv13",             bind_parse_tls_method_options, 0 }, /* disable TLSv13 */
        { "no-tls-tickets",        bind_parse_no_tls_tickets,     0 }, /* disable session resumption tickets */
+       { "sigalgs",               bind_parse_sigalgs,            1 }, /* set SSL signature algorithms */
        { "ssl",                   bind_parse_ssl,                0 }, /* enable SSL processing */
        { "ssl-min-ver",           bind_parse_tls_method_minmax,  1 }, /* minimum version */
        { "ssl-max-ver",           bind_parse_tls_method_minmax,  1 }, /* maximum version */
@@ -2152,6 +2207,9 @@ static struct cfg_kw_list cfg_kws = {ILH, {
 #if defined(SSL_CTX_set1_curves_list)
        { CFG_GLOBAL, "ssl-default-bind-curves", ssl_parse_global_curves },
 #endif
+#if defined(SSL_CTX_set1_sigalgs_list)
+       { CFG_GLOBAL, "ssl-default-bind-sigalgs", ssl_parse_global_sigalgs },
+#endif
 #ifdef HAVE_SSL_CTX_SET_CIPHERSUITES
        { CFG_GLOBAL, "ssl-default-bind-ciphersuites", ssl_parse_global_ciphersuites },
        { CFG_GLOBAL, "ssl-default-server-ciphersuites", ssl_parse_global_ciphersuites },

diff --git a/src/ssl_crtlist.c b/src/ssl_crtlist.c
index 741e6aed6e91009ffb7526a328dea3b93487162a..3d3ae407e3efc284654df5613911c6a05d2f1c65 100644 (file)
--- a/src/ssl_crtlist.c
+++ b/src/ssl_crtlist.c
@@ -74,6 +74,9 @@ void ssl_sock_free_ssl_conf(struct ssl_bind_conf *conf)
 #endif
                ha_free(&conf->curves);
                ha_free(&conf->ecdhe);
+#if defined(SSL_CTX_set1_sigalgs_list)
+               ha_free(&conf->sigalgs);
+#endif
        }
 }
 
@@ -151,6 +154,13 @@ struct ssl_bind_conf *crtlist_dup_ssl_conf(struct ssl_bind_conf *src)
        dst->ssl_methods.min = src->ssl_methods.min;
        dst->ssl_methods.max = src->ssl_methods.max;
 
+#if defined(SSL_CTX_set1_sigalgs_list)
+       if (src->sigalgs) {
+               dst->sigalgs = strdup(src->sigalgs);
+               if (!dst->sigalgs)
+                       goto error;
+       }
+#endif
        return dst;
 
 error:

diff --git a/src/ssl_sock.c b/src/ssl_sock.c
index a32ff413e64a7b6d76f93c1c702ce523c5093ec8..b44b5ce9283e805dc89e7bc8dc284fc58c9f5c21 100644 (file)
--- a/src/ssl_sock.c
+++ b/src/ssl_sock.c
@@ -4570,6 +4570,9 @@ static int ssl_sock_prepare_ctx(struct bind_conf *bind_conf, struct ssl_bind_con
 #endif
        const char *conf_curves = NULL;
        X509_STORE *store = SSL_CTX_get_cert_store(ctx);
+#if defined(SSL_CTX_set1_sigalgs_list)
+       const char *conf_sigalgs = NULL;
+#endif
 
        if (ssl_conf) {
                struct tls_version_filter *conf_ssl_methods = &ssl_conf->ssl_methods;
@@ -4772,6 +4775,17 @@ static int ssl_sock_prepare_ctx(struct bind_conf *bind_conf, struct ssl_bind_con
 #endif /* HA_OPENSSL_VERSION_NUMBER >= 0x10101000L */
        }
 
+#if defined(SSL_CTX_set1_sigalgs_list)
+       conf_sigalgs = (ssl_conf && ssl_conf->sigalgs) ? ssl_conf->sigalgs : bind_conf->ssl_conf.sigalgs;
+       if (conf_sigalgs) {
+               if (!SSL_CTX_set1_sigalgs_list(ctx, conf_sigalgs)) {
+                       memprintf(err, "%sProxy '%s': unable to set SSL Signature Algorithm list to '%s' for bind '%s' at [%s:%d].\n",
+                                 err && *err ? *err : "", curproxy->id, conf_sigalgs, bind_conf->arg, bind_conf->file, bind_conf->line);
+                       cfgerr |= ERR_ALERT | ERR_FATAL;
+               }
+       }
+#endif
+
        return cfgerr;
 }