hs-v3: Close client intro circuits if the descriptor is replaced

When storing a descriptor in the client cache, if we are about to replace an
existing descriptor, make sure to close every introduction circuits of the old
descriptor so we don't have leftovers lying around.

Ticket 27471 describes a situation where tor is sending an INTRODUCE1 cell on
an introduction circuit for which it doesn't have a matching intro point
object (taken from the descriptor).

The main theory is that, after a new descriptor showed up, the introduction
points changed which led to selecting an introduction circuit not used by the
service anymore thus for which we are unable to find the corresponding
introduction point within the descriptor we just fetched.

Closes #27471.

Signed-off-by: David Goulet <dgoulet@torproject.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/feature/hs/hs_client.h b/src/feature/hs/hs_client.h
index fb4f9e9e9f..f6fb167ea2 100644
--- a/src/feature/hs/hs_client.h
+++ b/src/feature/hs/hs_client.h
@@ -77,6 +77,7 @@ int hs_config_client_authorization(const or_options_t *options,
                                    int validate_only);
 
 int hs_client_reextend_intro_circuit(origin_circuit_t *circ);
+void hs_client_close_intro_circuits_from_desc(const hs_descriptor_t *desc);
 
 void hs_client_purge_state(void);