_gnutls_record_overhead: count content type octet in plaintext

In TLS 1.3, TLSInnerPlaintext has the 'type' field followed by the
padding.  Exclude it from the overhead calculation.

Signed-off-by: Daiki Ueno <dueno@redhat.com>

diff --git a/lib/dtls.c b/lib/dtls.c
index 0966a0b6f6f249759e1490f667986f2279851e3b..07c3495a46286adc637eabe605732b432f0e3dad 100644 (file)
--- a/lib/dtls.c
+++ b/lib/dtls.c
@@ -508,6 +508,10 @@ unsigned _gnutls_record_overhead(const version_entry_st *ver,
        if (unlikely(cipher == NULL))
                return 0;
 
+       /* 1 octet content type in the unencrypted content */
+       if (ver->tls13_sem)
+               total++;
+
        if (mac->id == GNUTLS_MAC_AEAD) {
                if (!ver->tls13_sem)
                        total += _gnutls_cipher_get_explicit_iv_size(cipher);

diff --git a/tests/gnutls_record_overhead.c b/tests/gnutls_record_overhead.c
index 2f17420a386553ac08569a5959af8b17f2882e57..f07f0b232b82b4d42d4de723da64c71003986b81 100644 (file)
--- a/tests/gnutls_record_overhead.c
+++ b/tests/gnutls_record_overhead.c
@@ -56,27 +56,35 @@ unsigned _gnutls_record_overhead(const version_entry_st *ver,
                                 const mac_entry_st *mac,
                                 unsigned max);
 
-#define OVERHEAD(c, m) \
-       _gnutls_record_overhead(version_to_entry(GNUTLS_TLS1_2), cipher_to_entry(c), mac_to_entry(m), \
+#define OVERHEAD(v, c, m)                                              \
+       _gnutls_record_overhead(version_to_entry(v), cipher_to_entry(c), mac_to_entry(m), \
                                0)
 
-#define MAX_OVERHEAD(c, m) \
-       _gnutls_record_overhead(version_to_entry(GNUTLS_TLS1_2), cipher_to_entry(c), mac_to_entry(m), \
+#define MAX_OVERHEAD(v, c, m)                                          \
+       _gnutls_record_overhead(version_to_entry(v), cipher_to_entry(c), mac_to_entry(m), \
                                1)
 
 static void check_aes_gcm(void **glob_state)
 {
        const unsigned ov = 16+8;
        /* Under AES-GCM the overhead is constant */
-       assert_int_equal(OVERHEAD(GNUTLS_CIPHER_AES_128_GCM, GNUTLS_MAC_AEAD), ov);
-       assert_int_equal(MAX_OVERHEAD(GNUTLS_CIPHER_AES_128_GCM, GNUTLS_MAC_AEAD), ov);
+       assert_int_equal(OVERHEAD(GNUTLS_TLS1_2, GNUTLS_CIPHER_AES_128_GCM, GNUTLS_MAC_AEAD), ov);
+       assert_int_equal(MAX_OVERHEAD(GNUTLS_TLS1_2, GNUTLS_CIPHER_AES_128_GCM, GNUTLS_MAC_AEAD), ov);
+}
+
+static void check_tls13_aes_gcm(void **glob_state)
+{
+       const unsigned ov = 16+1;
+       /* Under AES-GCM the overhead is constant */
+       assert_int_equal(OVERHEAD(GNUTLS_TLS1_3, GNUTLS_CIPHER_AES_128_GCM, GNUTLS_MAC_AEAD), ov);
+       assert_int_equal(MAX_OVERHEAD(GNUTLS_TLS1_3, GNUTLS_CIPHER_AES_128_GCM, GNUTLS_MAC_AEAD), ov);
 }
 
 static void check_aes_sha1_min(void **glob_state)
 {
        const unsigned mac = 20;
        const unsigned block = 16;
-       assert_int_equal(OVERHEAD(GNUTLS_CIPHER_AES_128_CBC, GNUTLS_MAC_SHA1), 1+mac+block);
+       assert_int_equal(OVERHEAD(GNUTLS_TLS1_2, GNUTLS_CIPHER_AES_128_CBC, GNUTLS_MAC_SHA1), 1+mac+block);
 }
 
 static void check_aes_sha1_max(void **glob_state)
@@ -84,13 +92,14 @@ static void check_aes_sha1_max(void **glob_state)
        const unsigned mac = 20;
        const unsigned block = 16;
 
-       assert_int_equal(MAX_OVERHEAD(GNUTLS_CIPHER_AES_128_CBC, GNUTLS_MAC_SHA1), block+mac+block);
+       assert_int_equal(MAX_OVERHEAD(GNUTLS_TLS1_2, GNUTLS_CIPHER_AES_128_CBC, GNUTLS_MAC_SHA1), block+mac+block);
 }
 
 int main(void)
 {
        const struct CMUnitTest tests[] = {
                cmocka_unit_test(check_aes_gcm),
+               cmocka_unit_test(check_tls13_aes_gcm),
                cmocka_unit_test(check_aes_sha1_min),
                cmocka_unit_test(check_aes_sha1_max)
        };