selftests: tls: add a selftest for wrapping rec_seq

Set the initial rec_seq to 0xffffffffffffffff so that it wraps
immediately. The send() call should fail with EBADMSG.

A bug in this code was fixed in commit cfaa80c ("net/tls: do not
free tls_rec on async operation in bpf_exec_tx_verdict()").

Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20775fcfd0371422921ee60a42de170c0398ac10.1729244987.git.sd@queasysnail.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

tools/testing/selftests/net/tls.c

@@ -266,6 +266,25 @@ TEST_F(tls_basic, bad_cipher)
 	EXPECT_EQ(setsockopt(self->fd, SOL_TLS, TLS_TX, &tls12, sizeof(struct tls12_crypto_info_aes_gcm_128)), -1);
 }
 
+TEST_F(tls_basic, recseq_wrap)
+{
+	struct tls_crypto_info_keys tls12;
+	char const *test_str = "test_read";
+	int send_len = 10;
+
+	if (self->notls)
+		SKIP(return, "no TLS support");
+
+	tls_crypto_info_init(TLS_1_2_VERSION, TLS_CIPHER_AES_GCM_128, &tls12);
+	memset(&tls12.aes128.rec_seq, 0xff, sizeof(tls12.aes128.rec_seq));
+
+	ASSERT_EQ(setsockopt(self->fd, SOL_TLS, TLS_TX, &tls12, tls12.len), 0);
+	ASSERT_EQ(setsockopt(self->cfd, SOL_TLS, TLS_RX, &tls12, tls12.len), 0);
+
+	EXPECT_EQ(send(self->fd, test_str, send_len, 0), -1);
+	EXPECT_EQ(errno, EBADMSG);
+}
+
 FIXTURE(tls)
 {
 	int fd, cfd;