test_hs_descriptor: Add a test case that fails without the fix for 40793

This adds a bit more to hs_descriptor/test_decode_descriptor, mostly
testing pow-params and triggering the tor_assert() in issue #40793.

There was no mechanism for adding arbitrary test strings to the
encrypted portion of the desc without duplicating encode logic. One
option might be to publicize get_inner_encrypted_layer_plaintext enough
to add a mock implementation. In this patch I opt for what seems like
the simplest solution, at the cost of a small amount of #ifdef noise.
The unpacked descriptor grows a new test-only member that's used for
dropping arbitrary data in at encode time.

Signed-off-by: Micah Elizabeth Scott <beth@torproject.org>

1 files changed, 12 insertions, 0 deletions

diff --git a/src/test/hs_test_helpers.c b/src/test/hs_test_helpers.c
index 20b225ba4a..4ef2398095 100644
--- a/src/test/hs_test_helpers.c
+++ b/src/test/hs_test_helpers.c
@@ -354,6 +354,18 @@ hs_helper_desc_equal(const hs_descriptor_t *desc1,
     }
   }
 
+  /* Proof of Work DoS mitigation options */
+  tt_int_op(!!desc1->encrypted_data.pow_params, OP_EQ,
+            !!desc2->encrypted_data.pow_params);
+  if (desc1->encrypted_data.pow_params && desc2->encrypted_data.pow_params) {
+    hs_pow_desc_params_t *params1 = desc1->encrypted_data.pow_params;
+    hs_pow_desc_params_t *params2 = desc2->encrypted_data.pow_params;
+    tt_int_op(params1->type, OP_EQ, params2->type);
+    tt_mem_op(params1->seed, OP_EQ, params2->seed, HS_POW_SEED_LEN);
+    tt_int_op(params1->suggested_effort, OP_EQ, params2->suggested_effort);
+    tt_int_op(params1->expiration_time, OP_EQ, params2->expiration_time);
+  }
+
   /* Introduction points. */
   {
     tt_assert(desc1->encrypted_data.intro_points);