commit f9f450d688cc74403393dbe579ca9d92d98bfe13 Author: Nick Mathewson <nickm@torproject.org> Date: Wed Jun 11 09:33:20 2014 -0400 Also raise the check for 0 circuit ID in created cell. And add a comment about why conditions that would cause us to drop a cell should get checked before actions that would cause us to send a destroy cell. Spotted by 'cypherpunks'. And note that these issues have been present since 0.0.8pre1 (commit 0da256ef), where we added a "shutting down" state, and started responding to all create cells with DESTROY when shutting down. --- changes/bug12191 | 7 ++++--- src/or/command.c | 19 +++++++++++-------- 2 files changed, 15 insertions(+), 11 deletions(-) diff --git a/changes/bug12191 b/changes/bug12191 index 7fe1c55..77589ab 100644 --- a/changes/bug12191 +++ b/changes/bug12191 @@ -1,6 +1,7 @@ o Minor bugfixes: - - We now drop CREATE cells for already-existent circuit IDs, regardless - of other factors that might otherwise have called for DESTROY cells. - Fixes bug 12191; bugfix on 0.2.??? + - We now drop CREATE cells for already-existent circuit IDs and + for zero-valued circuit IDs, regardless of other factors that + might otherwise have called for DESTROY cells. Fixes bug 12191; + bugfix on 0.0.8pre1. diff --git a/src/or/command.c b/src/or/command.c index 51fb640..fa2a0e7 100644 --- a/src/or/command.c +++ b/src/or/command.c @@ -227,6 +227,17 @@ command_process_create_cell(cell_t *cell, channel_t *chan) (unsigned)cell->circ_id, U64_PRINTF_ARG(chan->global_identifier), chan); + /* We check for the conditions that would make us drop the cell before + * we check for the conditions that would make us send a DESTROY back, + * since those conditions would make a DESTROY nonsensical. */ + if (cell->circ_id == 0) { + log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, + "Received a create cell (type %d) from %s with zero circID; " + " ignoring.", (int)cell->command, + channel_get_actual_remote_descr(chan)); + return; + } + if (circuit_id_in_use_on_channel(cell->circ_id, chan)) { const node_t *node = node_get_by_id(chan->identity_digest); log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, @@ -265,14 +276,6 @@ command_process_create_cell(cell_t *cell, channel_t *chan) return; } - if (cell->circ_id == 0) { - log_fn(LOG_PROTOCOL_WARN, LD_PROTOCOL, - "Received a create cell (type %d) from %s with zero circID; " - " ignoring.", (int)cell->command, - channel_get_actual_remote_descr(chan)); - return; - } - /* If the high bit of the circuit ID is not as expected, close the * circ. */ if (chan->wide_circ_ids)