[tor-commits] [tor/master] hs-v3: Close pending SOCKS connection on descriptor fetch error

[nickm at torproject.org]

commit c232b6b59cc136f7053922b3efc14afd5c34b6ec
Author: David Goulet <dgoulet at torproject.org>
Date:   Tue Sep 26 10:45:24 2017 -0400

    hs-v3: Close pending SOCKS connection on descriptor fetch error
    
    Signed-off-by: David Goulet <dgoulet at torproject.org>
---
 src/or/hs_client.c | 111 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 110 insertions(+), 1 deletion(-)

diff --git a/src/or/hs_client.c b/src/or/hs_client.c
index 8ed19529b..6f81ea09e 100644
--- a/src/or/hs_client.c
+++ b/src/or/hs_client.c
@@ -32,6 +32,58 @@
 #include "hs_ntor.h"
 #include "circuitbuild.h"
 #include "networkstatus.h"
+#include "reasons.h"
+
+/* Return a human-readable string for the client fetch status code. */
+static const char *
+fetch_status_to_string(hs_client_fetch_status_t status)
+{
+  switch (status) {
+  case HS_CLIENT_FETCH_ERROR:
+    return "Internal error";
+  case HS_CLIENT_FETCH_LAUNCHED:
+    return "Descriptor fetch launched";
+  case HS_CLIENT_FETCH_HAVE_DESC:
+    return "Already have descriptor";
+  case HS_CLIENT_FETCH_NO_HSDIRS:
+    return "No more HSDir available to query";
+  case HS_CLIENT_FETCH_NOT_ALLOWED:
+    return "Fetching descriptors is not allowed";
+  case HS_CLIENT_FETCH_MISSING_INFO:
+    return "Missing directory information";
+  case HS_CLIENT_FETCH_PENDING:
+    return "Pending descriptor fetch";
+  default:
+    return "(Unknown client fetch status code)";
+  }
+}
+
+/* Return true iff tor should close the SOCKS request(s) for the descriptor
+ * fetch that ended up with this given status code. */
+static int
+fetch_status_should_close_socks(hs_client_fetch_status_t status)
+{
+  switch (status) {
+  case HS_CLIENT_FETCH_NO_HSDIRS:
+    /* No more HSDir to query, we can't complete the SOCKS request(s). */
+  case HS_CLIENT_FETCH_ERROR:
+    /* The fetch triggered an internal error. */
+  case HS_CLIENT_FETCH_NOT_ALLOWED:
+    /* Client is not allowed to fetch (FetchHidServDescriptors 0). */
+    goto close;
+  case HS_CLIENT_FETCH_MISSING_INFO:
+  case HS_CLIENT_FETCH_HAVE_DESC:
+  case HS_CLIENT_FETCH_PENDING:
+  case HS_CLIENT_FETCH_LAUNCHED:
+    /* The rest doesn't require tor to close the SOCKS request(s). */
+    goto no_close;
+  }
+
+ no_close:
+  return 0;
+ close:
+  return 1;
+}
 
 /* Cancel all descriptor fetches currently in progress. */
 static void
@@ -136,6 +188,51 @@ directory_request_is_pending(const ed25519_public_key_t *identity_pk)
   return ret;
 }
 
+/* We failed to fetch a descriptor for the service with <b>identity_pk</b>
+ * because of <b>status</b>. Find all pending SOCKS connections for this
+ * service that are waiting on the descriptor and close them with
+ * <b>reason</b>. */
+static void
+close_all_socks_conns_waiting_for_desc(const ed25519_public_key_t *identity_pk,
+                                       hs_client_fetch_status_t status,
+                                       int reason)
+{
+  unsigned int count = 0;
+  time_t now = approx_time();
+  smartlist_t *conns =
+    connection_list_by_type_state(CONN_TYPE_AP, AP_CONN_STATE_RENDDESC_WAIT);
+
+  SMARTLIST_FOREACH_BEGIN(conns, connection_t *, base_conn) {
+    entry_connection_t *entry_conn = TO_ENTRY_CONN(base_conn);
+    const edge_connection_t *edge_conn = ENTRY_TO_EDGE_CONN(entry_conn);
+
+    /* Only consider the entry connections that matches the service for which
+     * we tried to get the descriptor */
+    if (!edge_conn->hs_ident ||
+        !ed25519_pubkey_eq(identity_pk,
+                           &edge_conn->hs_ident->identity_pk)) {
+      continue;
+    }
+    assert_connection_ok(base_conn, now);
+    /* Unattach the entry connection which will close for the reason. */
+    connection_mark_unattached_ap(entry_conn, reason);
+    count++;
+  } SMARTLIST_FOREACH_END(base_conn);
+
+  if (count > 0) {
+    char onion_address[HS_SERVICE_ADDR_LEN_BASE32 + 1];
+    hs_build_address(identity_pk, HS_VERSION_THREE, onion_address);
+    log_notice(LD_REND, "Closed %u streams for service %s.onion "
+                        "for reason %s. Fetch status: %s.",
+               count, safe_str_client(onion_address),
+               stream_end_reason_to_string(reason),
+               fetch_status_to_string(status));
+  }
+
+  /* No ownership of the object(s) in this list. */
+  smartlist_free(conns);
+}
+
 /* A v3 HS circuit successfully connected to the hidden service. Update the
  * stream state at <b>hs_conn_ident</b> appropriately. */
 static void
@@ -1037,6 +1134,8 @@ hs_client_any_intro_points_usable(const ed25519_public_key_t *service_pk,
 int
 hs_client_refetch_hsdesc(const ed25519_public_key_t *identity_pk)
 {
+  int ret;
+
   tor_assert(identity_pk);
 
   /* Are we configured to fetch descriptors? */
@@ -1080,7 +1179,17 @@ hs_client_refetch_hsdesc(const ed25519_public_key_t *identity_pk)
     return HS_CLIENT_FETCH_PENDING;
   }
 
-  return fetch_v3_desc(identity_pk);
+  /* Try to fetch the desc and if we encounter an unrecoverable error, mark the
+   * desc as unavailable for now. */
+  ret = fetch_v3_desc(identity_pk);
+  if (fetch_status_should_close_socks(ret)) {
+    close_all_socks_conns_waiting_for_desc(identity_pk, ret,
+                                           END_STREAM_REASON_RESOLVEFAILED);
+    /* Remove HSDir fetch attempts so that we can retry later if the user
+     * wants us to regardless of if we closed any connections. */
+    purge_hid_serv_request(identity_pk);
+  }
+  return ret;
 }
 
 /* This is called when we are trying to attach an AP connection to these