Error out when forcing an unsupported TLS version

If the result of a SSL_{CTX_,}set_{min,max}_proto_version() call
leaves the min and max version identical, and support for that version
is compiled out of the library, return an error.  Such an object has
no hope of successfully completing a handshake, and this error may
be easier to decipher than the resulting handshake failure.

Reviewed-by: Rich Salz <rsalz@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/3422)

1 files changed, 122 insertions, 8 deletions

diff --git a/ssl/ssl_lib.c b/ssl/ssl_lib.c
index 9add3bea11..cef8e41c6f 100644
--- a/ssl/ssl_lib.c
+++ b/ssl/ssl_lib.c
@@ -400,6 +400,116 @@ static int dane_tlsa_add(SSL_DANE *dane,
     return 1;
 }
 
+/*
+ * Return 0 if there is only one version configured and it was disabled
+ * at configure time.  Return 1 otherwise.
+ */
+static int ssl_check_allowed_versions(int min_version, int max_version)
+{
+    int minisdtls = 0, maxisdtls = 0;
+
+    /* Figure out if we're doing DTLS versions or TLS versions */
+    if (min_version == DTLS1_BAD_VER
+        || min_version >> 8 == DTLS1_VERSION_MAJOR)
+        minisdtls = 1;
+    if (max_version == DTLS1_BAD_VER
+        || max_version >> 8 == DTLS1_VERSION_MAJOR)
+        maxisdtls = 1;
+    /* A wildcard version of 0 could be DTLS or TLS. */
+    if ((minisdtls && !maxisdtls && max_version != 0)
+        || (maxisdtls && !minisdtls && min_version != 0)) {
+        /* Mixing DTLS and TLS versions will lead to sadness; deny it. */
+        return 0;
+    }
+
+    if (minisdtls || maxisdtls) {
+        /* Do DTLS version checks. */
+        if (min_version == 0)
+            /* Ignore DTLS1_BAD_VER */
+            min_version = DTLS1_VERSION;
+        if (max_version == 0)
+            max_version = DTLS1_2_VERSION;
+#ifdef OPENSSL_NO_DTLS1_2
+        if (max_version == DTLS1_2_VERSION)
+            max_version = DTLS1_VERSION;
+#endif
+#ifdef OPENSSL_NO_DTLS1
+        if (min_version == DTLS1_VERSION)
+            min_version = DTLS1_2_VERSION;
+#endif
+	/* Done massaging versions; do the check. */
+	if (0
+#ifdef OPENSSL_NO_DTLS1
+            || (DTLS_VERSION_GE(min_version, DTLS1_VERSION)
+                && DTLS_VERSION_GE(DTLS1_VERSION, max_version))
+#endif
+#ifdef OPENSSL_NO_DTLS1_2
+            || (DTLS_VERSION_GE(min_version, DTLS1_2_VERSION)
+                && DTLS_VERSION_GE(DTLS1_2_VERSION, max_version))
+#endif
+            )
+            return 0;
+    } else {
+        /* Regular TLS version checks. */
+	if (min_version == 0)
+	    min_version = SSL3_VERSION;
+	if (max_version == 0)
+	    max_version = TLS1_3_VERSION;
+#ifdef OPENSSL_NO_TLS1_3
+	if (max_version == TLS1_3_VERSION)
+	    max_version = TLS1_2_VERSION;
+#endif
+#ifdef OPENSSL_NO_TLS1_2
+	if (max_version == TLS1_2_VERSION)
+	    max_version = TLS1_1_VERSION;
+#endif
+#ifdef OPENSSL_NO_TLS1_1
+	if (max_version == TLS1_1_VERSION)
+	    max_version = TLS1_VERSION;
+#endif
+#ifdef OPENSSL_NO_TLS1
+	if (max_version == TLS1_VERSION)
+	    max_version = SSL3_VERSION;
+#endif
+#ifdef OPENSSL_NO_SSL3
+	if (min_version == SSL3_VERSION)
+	    min_version = TLS1_VERSION;
+#endif
+#ifdef OPENSSL_NO_TLS1
+	if (min_version == TLS1_VERSION)
+	    min_version = TLS1_1_VERSION;
+#endif
+#ifdef OPENSSL_NO_TLS1_1
+	if (min_version == TLS1_1_VERSION)
+	    min_version = TLS1_2_VERSION;
+#endif
+#ifdef OPENSSL_NO_TLS1_2
+	if (min_version == TLS1_2_VERSION)
+	    min_version = TLS1_3_VERSION;
+#endif
+	/* Done massaging versions; do the check. */
+	if (0
+#ifdef OPENSSL_NO_SSL3
+            || (min_version <= SSL3_VERSION && SSL3_VERSION <= max_version)
+#endif
+#ifdef OPENSSL_NO_TLS1
+            || (min_version <= TLS1_VERSION && TLS1_VERSION <= max_version)
+#endif
+#ifdef OPENSSL_NO_TLS1_1
+            || (min_version <= TLS1_1_VERSION && TLS1_1_VERSION <= max_version)
+#endif
+#ifdef OPENSSL_NO_TLS1_2
+            || (min_version <= TLS1_2_VERSION && TLS1_2_VERSION <= max_version)
+#endif
+#ifdef OPENSSL_NO_TLS1_3
+            || (min_version <= TLS1_3_VERSION && TLS1_3_VERSION <= max_version)
+#endif
+            )
+            return 0;
+    }
+    return 1;
+}
+
 static void clear_ciphers(SSL *s)
 {
     /* clear the current cipher */
@@ -2009,11 +2119,13 @@ long SSL_ctrl(SSL *s, int cmd, long larg, void *parg)
         else
             return 0;
     case SSL_CTRL_SET_MIN_PROTO_VERSION:
-        return ssl_set_version_bound(s->ctx->method->version, (int)larg,
-                                     &s->min_proto_version);
+        return ssl_check_allowed_versions(larg, s->max_proto_version)
+               && ssl_set_version_bound(s->ctx->method->version, (int)larg,
+                                        &s->min_proto_version);
     case SSL_CTRL_SET_MAX_PROTO_VERSION:
-        return ssl_set_version_bound(s->ctx->method->version, (int)larg,
-                                     &s->max_proto_version);
+        return ssl_check_allowed_versions(s->min_proto_version, larg)
+               && ssl_set_version_bound(s->ctx->method->version, (int)larg,
+                                        &s->max_proto_version);
     default:
         return (s->method->ssl_ctrl(s, cmd, larg, parg));
     }
@@ -2143,11 +2255,13 @@ long SSL_CTX_ctrl(SSL_CTX *ctx, int cmd, long larg, void *parg)
     case SSL_CTRL_CLEAR_CERT_FLAGS:
         return (ctx->cert->cert_flags &= ~larg);
     case SSL_CTRL_SET_MIN_PROTO_VERSION:
-        return ssl_set_version_bound(ctx->method->version, (int)larg,
-                                     &ctx->min_proto_version);
+        return ssl_check_allowed_versions(larg, ctx->max_proto_version)
+               && ssl_set_version_bound(ctx->method->version, (int)larg,
+                                        &ctx->min_proto_version);
     case SSL_CTRL_SET_MAX_PROTO_VERSION:
-        return ssl_set_version_bound(ctx->method->version, (int)larg,
-                                     &ctx->max_proto_version);
+        return ssl_check_allowed_versions(ctx->min_proto_version, larg)
+               && ssl_set_version_bound(ctx->method->version, (int)larg,
+                                        &ctx->max_proto_version);
     default:
         return (ctx->method->ssl_ctx_ctrl(ctx, cmd, larg, parg));
     }