commit 9409c7f2f52f192eaf497c56daa485d75358de65
Author: Nick Mathewson <ni...@torproject.org>
Date: Mon Mar 8 13:41:20 2021 -0500
Don't warn about missing guard state if controller picked first hop
See comments about why this needs a new flag and we can't just use
CIRCUIT_PURPOSE_CONTROLLER.
Fixes #40285; bugfix on 0.3.2.1-alpha.
---
changes/bug40285_045 | 4 ++++
src/core/or/circuitbuild.c | 18 +++++++++++++-----
src/core/or/circuitlist.h | 3 ++-
src/core/or/origin_circuit_st.h | 12 ++++++++++++
src/feature/control/control_cmd.c | 1 +
5 files changed, 32 insertions(+), 6 deletions(-)
diff --git a/changes/bug40285_045 b/changes/bug40285_045
new file mode 100644
index 0000000000..db4f73cde0
--- /dev/null
+++ b/changes/bug40285_045
@@ -0,0 +1,4 @@
+ o Minor bugfixes (controller):
+ - Fix a "BUG" warning that would appear when a controller chooses the
+ first hop for a circuit, and that circuit completes. Fixes
+ bug 40285; bugfix on 0.3.2.1-alpha.
diff --git a/src/core/or/circuitbuild.c b/src/core/or/circuitbuild.c
index c0c918abe4..78501c0aa2 100644
--- a/src/core/or/circuitbuild.c
+++ b/src/core/or/circuitbuild.c
@@ -881,14 +881,22 @@ circuit_pick_extend_handshake(uint8_t *cell_type_out,
}
/**
- * Return true iff <b>purpose</b> is a purpose for a circuit which is
- * allowed to have no guard configured, even if the circuit is multihop
+ * Return true iff <b>circ</b> is allowed
+ * to have no guard configured, even if the circuit is multihop
* and guards are enabled.
*/
static int
-circuit_purpose_may_omit_guard(int purpose)
+circuit_may_omit_guard(const origin_circuit_t *circ)
{
- switch (purpose) {
+ if (BUG(!circ))
+ return 0;
+
+ if (circ->first_hop_from_controller) {
+ /* The controller picked the first hop: that bypasses the guard system. */
+ return 1;
+ }
+
+ switch (circ->base_.purpose) {
case CIRCUIT_PURPOSE_TESTING:
case CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT:
/* Testing circuits may omit guards because they're measuring
@@ -1019,7 +1027,7 @@ circuit_build_no_more_hops(origin_circuit_t *circ)
guard_usable_t r;
if (! circ->guard_state) {
if (circuit_get_cpath_len(circ) != 1 &&
- ! circuit_purpose_may_omit_guard(circ->base_.purpose) &&
+ ! circuit_may_omit_guard(circ) &&
get_options()->UseEntryGuards) {
log_warn(LD_BUG, "%d-hop circuit %p with purpose %d has no "
"guard state",
diff --git a/src/core/or/circuitlist.h b/src/core/or/circuitlist.h
index 3178e6cd0d..bd4a117e26 100644
--- a/src/core/or/circuitlist.h
+++ b/src/core/or/circuitlist.h
@@ -118,7 +118,8 @@
* bandwidth measurement, reachability test and address discovery from an
* authority using the NETINFO cell. */
#define CIRCUIT_PURPOSE_TESTING 21
-/** A controller made this circuit and Tor should not use it. */
+/** A controller made this circuit and Tor should not cannibalize it or attach
+ * streams to it without explicitly being told. */
#define CIRCUIT_PURPOSE_CONTROLLER 22
/** This circuit is used for path bias probing only */
#define CIRCUIT_PURPOSE_PATH_BIAS_TESTING 23
diff --git a/src/core/or/origin_circuit_st.h b/src/core/or/origin_circuit_st.h
index a45a6573dc..c40e84aed8 100644
--- a/src/core/or/origin_circuit_st.h
+++ b/src/core/or/origin_circuit_st.h
@@ -170,6 +170,18 @@ struct origin_circuit_t {
* not try to negotiate further circuit padding. */
unsigned padding_negotiation_failed : 1;
+ /**
+ * If this flag is set, then a controller chose the first hop of this
+ * circuit's path, and it's okay to ignore checks that we'd usually do
+ * on this circuit's first hop.
+ *
+ * This flag is distinct from the CIRCUIT_PURPOSE_CONTROLLER purpose: the
+ * purpose indicates _what tor can use the circuit for_. Controller-created
+ * circuits can still have the CIRCUIT_PURPOSE_GENERAL purpose if Tor is
+ * allowed to attach streams to them.
+ */
+ unsigned first_hop_from_controller : 1;
+
/**
* Tristate variable to guard against pathbias miscounting
* due to circuit purpose transitions changing the decision
diff --git a/src/feature/control/control_cmd.c
b/src/feature/control/control_cmd.c
index 5b75c24692..0456d709f5 100644
--- a/src/feature/control/control_cmd.c
+++ b/src/feature/control/control_cmd.c
@@ -819,6 +819,7 @@ handle_control_extendcircuit(control_connection_t *conn,
if (zero_circ) {
/* start a new circuit */
circ = origin_circuit_init(intended_purpose, 0);
+ circ->first_hop_from_controller = 1;
}
/* now circ refers to something that is ready to be extended */
_______________________________________________
tor-commits mailing list
tor-commits@lists.torproject.org
https://lists.torproject.org/cgi-bin/mailman/listinfo/tor-commits
