From 0699e96f1f65a89222f1dfe054e69957801a4f1c Mon Sep 17 00:00:00 2001 From: Bernd Edlinger Date: Mon, 11 Apr 2022 10:12:48 +0200 Subject: Fix an assertion in the DTLS server code This fixes an internal error alert from the server and an unexpected connection failure in the release version, but a failed assertion and a server crash in the debug version. Reproduce this issue with a DTLS server/client like that: ./openssl s_server -dtls -mtu 1500 ./openssl s_client -dtls -maxfraglen 512 In the debug version a crash happens in the Server now: ./openssl s_server -dtls -mtu 1500 Using default temp DH parameters ACCEPT ssl/statem/statem_dtls.c:269: OpenSSL internal error: Assertion failed: len == written Aborted (core dumped) While in the release version the handshake exceeds the negotiated max fragment size, and fails because of this: $ ./openssl s_server -dtls -mtu 1500 Using default temp DH parameters ACCEPT ERROR 4057152ADA7F0000:error:0A0000C2:SSL routines:do_dtls1_write:exceeds max fragment size:ssl/record/rec_layer_d1.c:826: shutting down SSL CONNECTION CLOSED From the client's point of view the connection fails with an Internal Error Alert: $ ./openssl s_client -dtls -maxfraglen 512 Connecting to ::1 CONNECTED(00000003) 40B76343377F0000:error:0A000438:SSL routines:dtls1_read_bytes:tlsv1 alert internal error:ssl/record/rec_layer_d1.c:613:SSL alert number 80 and now the connection attempt fails unexpectedly. Reviewed-by: Tomas Mraz Reviewed-by: Matt Caswell (Merged from https://github.com/openssl/openssl/pull/18093) (cherry picked from commit e915c3f5381cd38ebdc1824c3ba9896ea7160103) --- test/dtls_mtu_test.c | 48 +++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 47 insertions(+), 1 deletion(-) (limited to 'test') diff --git a/test/dtls_mtu_test.c b/test/dtls_mtu_test.c index 612b76a3bc..7e1fe36cd9 100644 --- a/test/dtls_mtu_test.c +++ b/test/dtls_mtu_test.c @@ -185,12 +185,58 @@ static int run_mtu_tests(void) end: SSL_CTX_free(ctx); - bio_s_mempacket_test_free(); return ret; } +static int test_server_mtu_larger_than_max_fragment_length(void) +{ + SSL_CTX *ctx = NULL; + SSL *srvr_ssl = NULL, *clnt_ssl = NULL; + int rv = 0; + + if (!TEST_ptr(ctx = SSL_CTX_new(DTLS_method()))) + goto end; + + SSL_CTX_set_psk_server_callback(ctx, srvr_psk_callback); + SSL_CTX_set_psk_client_callback(ctx, clnt_psk_callback); + +#ifndef OPENSSL_NO_DH + if (!TEST_true(SSL_CTX_set_dh_auto(ctx, 1))) + goto end; +#endif + + if (!TEST_true(create_ssl_objects(ctx, ctx, &srvr_ssl, &clnt_ssl, + NULL, NULL))) + goto end; + + SSL_set_options(srvr_ssl, SSL_OP_NO_QUERY_MTU); + if (!TEST_true(DTLS_set_link_mtu(srvr_ssl, 1500))) + goto end; + + SSL_set_tlsext_max_fragment_length(clnt_ssl, + TLSEXT_max_fragment_length_512); + + if (!TEST_true(create_ssl_connection(srvr_ssl, clnt_ssl, + SSL_ERROR_NONE))) + goto end; + + rv = 1; + + end: + SSL_free(clnt_ssl); + SSL_free(srvr_ssl); + SSL_CTX_free(ctx); + return rv; +} + int setup_tests(void) { ADD_TEST(run_mtu_tests); + ADD_TEST(test_server_mtu_larger_than_max_fragment_length); return 1; } + +void cleanup_tests(void) +{ + bio_s_mempacket_test_free(); +} -- cgit v1.2.3