From: Matt Caswell <matt@openssl.org>
Date: Mon, 1 Dec 2014 23:57:44 +0000 (+0000)
Subject: Updates to s_client and s_server to remove the constant 28 (for IPv4 header
X-Git-Tag: OpenSSL_1_0_0p~35
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=82d7247fc5feca45c9a3526582912ccfe8e5f96a;p=oweals%2Fopenssl.git

Updates to s_client and s_server to remove the constant 28 (for IPv4 header
and UDP header) when setting an mtu. This constant is not always correct (e.g.
if using IPv6). Use the new DTLS_CTRL functions instead.

Reviewed-by: Tim Hudson <tjh@openssl.org>
(cherry picked from commit 464ce92026bd0c79186cbefa75470f39607110be)
---

diff --git a/apps/s_client.c b/apps/s_client.c
index 1e377debc0..fb170e256a 100644
--- a/apps/s_client.c
+++ b/apps/s_client.c
@@ -1018,10 +1018,22 @@ re_start:
 			BIO_ctrl(sbio, BIO_CTRL_DGRAM_SET_SEND_TIMEOUT, 0, &timeout);
 			}
 
-		if (socket_mtu > 28)
+		if (socket_mtu)
 			{
+			if(socket_mtu < DTLS_get_link_min_mtu(con))
+				{
+				BIO_printf(bio_err,"MTU too small. Must be at least %ld\n",
+					DTLS_get_link_min_mtu(con));
+				BIO_free(sbio);
+				goto shut;
+				}
 			SSL_set_options(con, SSL_OP_NO_QUERY_MTU);
-			SSL_set_mtu(con, socket_mtu - 28);
+			if(!DTLS_set_link_mtu(con, socket_mtu))
+				{
+				BIO_printf(bio_err, "Failed to set MTU\n");
+				BIO_free(sbio);
+				goto shut;
+				}
 			}
 		else
 			/* want to do MTU discovery */
diff --git a/apps/s_server.c b/apps/s_server.c
index f25f530d60..876d76a72d 100644
--- a/apps/s_server.c
+++ b/apps/s_server.c
@@ -1856,10 +1856,24 @@ static int sv_body(char *hostname, int s, unsigned char *context)
 			BIO_ctrl(sbio, BIO_CTRL_DGRAM_SET_SEND_TIMEOUT, 0, &timeout);
 			}
 
-		if (socket_mtu > 28)
+		if (socket_mtu)
 			{
+			if(socket_mtu < DTLS_get_link_min_mtu(con))
+				{
+				BIO_printf(bio_err,"MTU too small. Must be at least %ld\n",
+					DTLS_get_link_min_mtu(con));
+				ret = -1;
+				BIO_free(sbio);
+				goto err;
+				}
 			SSL_set_options(con, SSL_OP_NO_QUERY_MTU);
-			SSL_set_mtu(con, socket_mtu - 28);
+			if(!DTLS_set_link_mtu(con, socket_mtu))
+				{
+				BIO_printf(bio_err, "Failed to set MTU\n");
+				ret = -1;
+				BIO_free(sbio);
+				goto err;
+				}
 			}
 		else
 			/* want to do MTU discovery */