Add patch to mbedtls that fixes commissioning problem with retransmitted messages. (#1207)

.travis/script.sh

@@ -50,6 +50,7 @@ set -x
 [ $BUILD_TARGET != arm-gcc49 ] || {
     export PATH=/tmp/gcc-arm-none-eabi-4_9-2015q3/bin:$PATH || die
 
+    git checkout -- . || die
     git clean -xfd || die
     ./bootstrap || die
     COMMISSIONER=1 JOINER=1 DHCP6_CLIENT=1 DHCP6_SERVER=1 make -f examples/Makefile-cc2538 || die
@@ -57,6 +58,7 @@ set -x
     arm-none-eabi-size  output/bin/arm-none-eabi-ot-cli-mtd || die
     arm-none-eabi-size  output/bin/arm-none-eabi-ot-ncp || die
 
+    git checkout -- . || die
     git clean -xfd || die
     ./bootstrap || die
     COMMISSIONER=1 JOINER=1 DHCP6_CLIENT=1 DHCP6_SERVER=1 make -f examples/Makefile-da15000 || die
@@ -64,6 +66,7 @@ set -x
     arm-none-eabi-size  output/bin/arm-none-eabi-ot-cli-mtd || die
     arm-none-eabi-size  output/bin/arm-none-eabi-ot-ncp || die
 
+    git checkout -- . || die
     git clean -xfd || die
     ./bootstrap || die
     COMMISSIONER=1 JOINER=1 DHCP6_CLIENT=1 DHCP6_SERVER=1 make -f examples/Makefile-nrf52840 || die
@@ -75,6 +78,7 @@ set -x
 [ $BUILD_TARGET != arm-gcc54 ] || {
     export PATH=/tmp/gcc-arm-none-eabi-5_4-2016q3/bin:$PATH || die
 
+    git checkout -- . || die
     git clean -xfd || die
     ./bootstrap || die
     COMMISSIONER=1 JOINER=1 DHCP6_CLIENT=1 DHCP6_SERVER=1 make -f examples/Makefile-cc2538 || die
@@ -82,6 +86,7 @@ set -x
     arm-none-eabi-size  output/bin/arm-none-eabi-ot-cli-mtd || die
     arm-none-eabi-size  output/bin/arm-none-eabi-ot-ncp || die
 
+    git checkout -- . || die
     git clean -xfd || die
     ./bootstrap || die
     COMMISSIONER=1 JOINER=1 DHCP6_CLIENT=1 DHCP6_SERVER=1 make -f examples/Makefile-da15000 || die
@@ -89,6 +94,7 @@ set -x
     arm-none-eabi-size  output/bin/arm-none-eabi-ot-cli-mtd || die
     arm-none-eabi-size  output/bin/arm-none-eabi-ot-ncp || die
 
+    git checkout -- . || die
     git clean -xfd || die
     ./bootstrap || die
     COMMISSIONER=1 JOINER=1 DHCP6_CLIENT=1 DHCP6_SERVER=1 make -f examples/Makefile-nrf52840 || die

third_party/mbedtls/Makefile.am

@@ -71,6 +71,26 @@ libmbedcrypto_a_SOURCES                      += \
     repo/library/ssl_ticket.c                   \
     repo/library/ssl_tls.c                      \
     $(NULL)
+
+EXTRA_DIST                                                         += \
+    patch/0001-Fix-commissioning-problem-with-retransmissions.patch   \
+    $(NULL)
+    
+BUILT_SOURCES                                 = \
+    $(MBEDTLS_SRCDIR)/library/ssl_tls.c.patched \
+    $(NULL)
+
+$(MBEDTLS_SRCDIR)/library/ssl_tls.c.patched: $(abs_top_srcdir)/third_party/mbedtls/patch/0001-Fix-commissioning-problem-with-retransmissions.patch
+	chmod u+w $(abs_top_srcdir)/third_party/mbedtls/repo/library/
+	chmod u+w $(abs_top_srcdir)/third_party/mbedtls/repo/library/ssl_tls.c
+	if [ -e $@ ]; then patch -R $(abs_top_srcdir)/third_party/mbedtls/repo/library/ssl_tls.c $@; fi
+	patch $(abs_top_srcdir)/third_party/mbedtls/repo/library/ssl_tls.c $<
+	cp $(abs_top_srcdir)/third_party/mbedtls/patch/0001-Fix-commissioning-problem-with-retransmissions.patch $@
+
+all-local: libmbedcrypto.a
+	patch -R $(abs_top_srcdir)/third_party/mbedtls/repo/library/ssl_tls.c $(abs_top_srcdir)/third_party/mbedtls/patch/0001-Fix-commissioning-problem-with-retransmissions.patch
+	rm -f $(MBEDTLS_SRCDIR)/library/ssl_tls.c.patched
+
 endif  # OPENTHREAD_ENABLE_DTLS
 
 if OPENTHREAD_BUILD_COVERAGE

third_party/mbedtls/patch/0001-Fix-commissioning-problem-with-retransmissions.patch

@@ -0,0 +1,39 @@
+diff --git a/third_party/mbedtls/repo/library/ssl_tls.c b/third_party/mbedtls/repo/library/ssl_tls.c
+index 84a04ae..2153c80 100644
+--- a/third_party/mbedtls/repo/library/ssl_tls.c
++++ b/third_party/mbedtls/repo/library/ssl_tls.c
+@@ -3608,6 +3608,24 @@ static int ssl_parse_record_header( mbedtls_ssl_context *ssl )
+                                         "expected %d, received %d",
+                                         ssl->in_epoch, rec_epoch ) );
+ 
++#if defined(MBEDTLS_SSL_SRV_C)
++            /*
++             * Check for an epoch 0 Change Cipher Spec retransmission.
++             */
++            if( ssl->conf->endpoint == MBEDTLS_SSL_IS_SERVER &&
++                ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER &&
++                rec_epoch == 0 &&
++                ssl->in_epoch == 1 &&
++                ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE &&
++                ssl->in_left > 13 &&
++                ssl->in_buf[13] == MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE )
++            {
++                MBEDTLS_SSL_DEBUG_MSG( 1, ( "possible Client Key Exchange "
++                                            "retransmission" ) );
++                return( mbedtls_ssl_resend( ssl ) );
++            }
++#endif
++
+ #if defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE) && defined(MBEDTLS_SSL_SRV_C)
+             /*
+              * Check for an epoch 0 ClientHello. We can't use in_msg here to
+@@ -3737,7 +3755,8 @@ int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl )
+ 
+         ret = mbedtls_ssl_handle_message_type( ssl );
+ 
+-    } while( MBEDTLS_ERR_SSL_NON_FATAL == ret );
++    } while( MBEDTLS_ERR_SSL_NON_FATAL == ret ||
++             ( MBEDTLS_ERR_SSL_WANT_READ == ret && ssl->in_msglen ) );
+ 
+     if( 0 != ret )
+     {