commit ff410edec04793d6d72f9961acd2f13a5ee3b9b5 Author: Mike Perry <mikeperry-git@torproject.org> Date: Thu Feb 21 01:34:55 2019 +0000 Bug 29204: Inspect circuit queues before sending padding. Mitigates OOM conditions at relays. --- changes/bug29204 | 4 ++++ src/core/or/circuitpadding.c | 21 +++++++++++++++++---- 2 files changed, 21 insertions(+), 4 deletions(-) diff --git a/changes/bug29204 b/changes/bug29204 new file mode 100644 index 000000000..ec2cf67b2 --- /dev/null +++ b/changes/bug29204 @@ -0,0 +1,4 @@ + o Minor bugfixes (circuitpadding): + - Inspect circuit-level cell queue before sending padding, to avoid + sending padding while too much data is queued. Fixes bug 29204; + bugfix on 0.4.0.1-alpha. diff --git a/src/core/or/circuitpadding.c b/src/core/or/circuitpadding.c index 0dadc5213..ba6bfe1f5 100644 --- a/src/core/or/circuitpadding.c +++ b/src/core/or/circuitpadding.c @@ -61,6 +61,7 @@ #include "core/or/crypt_path_st.h" #include "core/or/circuit_st.h" #include "core/or/origin_circuit_st.h" +#include "core/or/or_circuit_st.h" #include "feature/nodelist/routerstatus_st.h" #include "feature/nodelist/node_st.h" #include "core/or/cell_st.h" @@ -81,6 +82,7 @@ static double circpad_distribution_sample(circpad_distribution_t dist); /** Cached consensus params */ static uint8_t circpad_global_max_padding_percent; static uint16_t circpad_global_allowed_cells; +static uint16_t circpad_max_circ_queued_cells; /** Global cell counts, for rate limiting */ static uint64_t circpad_global_padding_sent; @@ -1027,10 +1029,17 @@ circpad_send_padding_cell_for_callback(circpad_machine_state_t *mi) } else { // If we're a non-origin circ, we can just send from here as if we're the // edge. - log_fn(LOG_INFO,LD_CIRC, - "Callback: Sending padding to non-origin circuit."); - relay_send_command_from_edge(0, mi->on_circ, RELAY_COMMAND_DROP, NULL, - 0, NULL); + if (TO_OR_CIRCUIT(circ)->p_chan_cells.n <= circpad_max_circ_queued_cells) { + log_fn(LOG_INFO,LD_CIRC, + "Callback: Sending padding to non-origin circuit."); + relay_send_command_from_edge(0, mi->on_circ, RELAY_COMMAND_DROP, NULL, + 0, NULL); + } else { + static ratelim_t cell_lim = RATELIM_INIT(600); + log_fn_ratelim(&cell_lim,LOG_NOTICE,LD_CIRC, + "Too many cells (%d) in circ queue to send padding.", + TO_OR_CIRCUIT(circ)->p_chan_cells.n); + } } rep_hist_padding_count_write(PADDING_TYPE_DROP); @@ -1093,6 +1102,10 @@ circpad_new_consensus_params(const networkstatus_t *ns) circpad_global_max_padding_percent = networkstatus_get_param(ns, "circpad_global_max_padding_pct", 0, 0, 100); + + circpad_max_circ_queued_cells = + networkstatus_get_param(ns, "circpad_max_circ_queued_cells", + CIRCWINDOW_START_MAX, 0, 50*CIRCWINDOW_START_MAX); } /**