commit 418c2845d03bf425ac2a0a9758b89e151dc3b9aa Author: Andrea Shepard andrea@torproject.org Date: Thu Jun 13 20:49:01 2013 -0700

Don't queue more cells as a middle relay than the spec allows to be in flight --- changes/bug9063 | 3 +++ src/or/or.h | 8 ++++++++ src/or/relay.c | 28 +++++++++++++++++++++++++++- 3 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/changes/bug9063 b/changes/bug9063 new file mode 100644 index 0000000..dcbecf6 --- /dev/null +++ b/changes/bug9063 @@ -0,0 +1,3 @@ + o Normal bugfixes: + - Close any circuit that has more cells queued than the spec permits. + Fixes bug #9063; bugfix on 0.2.4.12. diff --git a/src/or/or.h b/src/or/or.h index ab5e3aa..36b6778 100644 --- a/src/or/or.h +++ b/src/or/or.h @@ -541,6 +541,8 @@ typedef enum { #define CIRCUIT_PURPOSE_IS_ESTABLISHED_REND(p) \ ((p) == CIRCUIT_PURPOSE_C_REND_JOINED || \ (p) == CIRCUIT_PURPOSE_S_REND_JOINED) +/** True iff the circuit_t c is actually an or_circuit_t */ +#define CIRCUIT_IS_ORCIRC(c) (((circuit_t *)(c))->magic == OR_CIRCUIT_MAGIC)

/** How many circuits do we want simultaneously in-progress to handle * a given stream? */ @@ -818,6 +820,12 @@ typedef enum { /** Amount to increment a stream window when we get a stream SENDME. */ #define STREAMWINDOW_INCREMENT 50

+/** Maximum number of queued cells on a circuit for which we are the + * midpoint before we give up and kill it. This must be >= circwindow + * to avoid killing innocent circuits. + */ +#define ORCIRC_MAX_MIDDLE_CELLS (11*(CIRCWINDOW_START_MAX)/10) + /* Cell commands. These values are defined in tor-spec.txt. */ #define CELL_PADDING 0 #define CELL_CREATE 1 diff --git a/src/or/relay.c b/src/or/relay.c index d57ceaa..a26d418 100644 --- a/src/or/relay.c +++ b/src/or/relay.c @@ -2466,8 +2466,10 @@ append_cell_to_circuit_queue(circuit_t *circ, channel_t *chan, cell_t *cell, cell_direction_t direction, streamid_t fromstream) { + or_circuit_t *orcirc = NULL; cell_queue_t *queue; int streams_blocked; + if (circ->marked_for_close) return;

@@ -2475,11 +2477,35 @@ append_cell_to_circuit_queue(circuit_t *circ, channel_t *chan, queue = &circ->n_chan_cells; streams_blocked = circ->streams_blocked_on_n_chan; } else { - or_circuit_t *orcirc = TO_OR_CIRCUIT(circ); + orcirc = TO_OR_CIRCUIT(circ); queue = &orcirc->p_chan_cells; streams_blocked = circ->streams_blocked_on_p_chan; }

+ /* Are we a middle circuit about to exceed ORCIRC_MAX_MIDDLE_CELLS? */ + if ((circ->n_chan != NULL) && CIRCUIT_IS_ORCIRC(circ)) { + orcirc = TO_OR_CIRCUIT(circ); + if (orcirc->p_chan) { + if (queue->n + 1 >= ORCIRC_MAX_MIDDLE_CELLS) { + /* Queueing this cell would put queue over the cap */ + log_warn(LD_CIRC, + "Got a cell exceeding the cap of %u in the %s direction " + "on middle circ ID %u on chan ID " U64_FORMAT + "; killing the circuit.", + ORCIRC_MAX_MIDDLE_CELLS, + (direction == CELL_DIRECTION_OUT) ? "n" : "p", + (direction == CELL_DIRECTION_OUT) ? + circ->n_circ_id : orcirc->p_circ_id, + U64_PRINTF_ARG( + (direction == CELL_DIRECTION_OUT) ? + circ->n_chan->global_identifier : + orcirc->p_chan->global_identifier)); + circuit_mark_for_close(circ, END_CIRC_REASON_RESOURCELIMIT); + return; + } + } + } + cell_queue_append_packed_copy(queue, cell, chan->wide_circ_ids);

/* If we have too many cells on the circuit, we should stop reading from