MU: Fix marshaling of TPM2Bs with sub types.

* The offset was not computed correctly if a NULL buffer was passed.
  The TSS MU spec states: If the 'buffer' parameter is NULL the
  implementation shall not write any marshaled data but the 'offset'
  parameter shall be updated as as though it had.
* The unnecessary test of NULL buffer and not NULL offset was removed
  and the corresponding unit test was adapted.
* Also a unit test which compares the result of NULL buffer and
  not NULL buffer marshaling was added.

Signed-off-by: Juergen Repp <Juergen.Repp@sit.fraunhofer.de>

1 files changed, 22 insertions, 1 deletions

diff --git a/test/unit/TPM2B-marshal.c b/test/unit/TPM2B-marshal.c
index deb5ba6b..301e2e2c 100644
--- a/test/unit/TPM2B-marshal.c
+++ b/test/unit/TPM2B-marshal.c
@@ -138,7 +138,28 @@ tpm2b_marshal_buffer_null_with_offset(void **state)
     offset = 10;
     rc = Tss2_MU_TPM2B_ECC_POINT_Marshal(&point, NULL, buffer_size, &offset);
     assert_int_equal (rc, TSS2_RC_SUCCESS);
-    assert_int_equal (offset, 10 + 2 + 2 + TPM2_MAX_ECC_KEY_BYTES + 2 + TPM2_MAX_ECC_KEY_BYTES);
+    assert_int_equal (offset, 10 + 2 + 2 + sizeof(value) + 2 + sizeof(value2));
+    offset = 0;
+    rc = Tss2_MU_TPM2B_DIGEST_Marshal(&dgst, NULL, buffer_size, &offset);
+    assert_int_equal (rc, TSS2_RC_SUCCESS);
+    /*
+     * TSS MU spec states:
+     * If the 'buffer' parameter is NULL the implementation shall not write
+     * any marshaled data but the 'offset' parameter shall be updated as
+     * though it had.
+     * The offset of call with NULL and not NULL buffer will be compared.
+     */
+    uint8_t buffer[offset];
+
+    size_t offset1 = 0;
+    rc = Tss2_MU_TPM2B_DIGEST_Marshal(&dgst, NULL, buffer_size, &offset1);
+    assert_int_equal (rc, TSS2_RC_SUCCESS);
+
+    size_t offset2 = 0;
+    rc = Tss2_MU_TPM2B_DIGEST_Marshal(&dgst, buffer, buffer_size, &offset2);
+    assert_int_equal (rc, TSS2_RC_SUCCESS);
+    assert_int_equal(offset1, offset2);
+
 }
 
 /*