commit ff8823d03cef50cb3a78f13a35558288e54c2173 Author: David Goulet <dgoulet@torproject.org> Date: Thu Oct 31 13:50:36 2019 -0400 dos: Account rejection in hs_dos_can_send_intro2 This required a small refactoring so we could count properly the INTRO2 sending disallow. Part of #31371 Signed-off-by: David Goulet <dgoulet@torproject.org> --- src/feature/hs/hs_dos.c | 20 +++++++++++++++++--- 1 file changed, 17 insertions(+), 3 deletions(-) diff --git a/src/feature/hs/hs_dos.c b/src/feature/hs/hs_dos.c index 19794e09d..81041475e 100644 --- a/src/feature/hs/hs_dos.c +++ b/src/feature/hs/hs_dos.c @@ -45,6 +45,9 @@ * introduction DoS defense. Disabled by default. */ #define HS_DOS_INTRODUCE_ENABLED_DEFAULT 0 +/* INTRODUCE2 rejected request counter. */ +static uint64_t intro2_rejected_count = 0; + /* Consensus parameters. The ESTABLISH_INTRO DoS cell extension have higher * priority than these values. If no extension is sent, these are used only by * the introduction point. */ @@ -163,12 +166,12 @@ hs_dos_can_send_intro2(or_circuit_t *s_intro_circ) * This can be set by the consensus, the ESTABLISH_INTRO cell extension or * the hardcoded values in tor code. */ if (!s_intro_circ->introduce2_dos_defense_enabled) { - return true; + goto allow; } /* Should not happen but if so, scream loudly. */ if (BUG(TO_CIRCUIT(s_intro_circ)->purpose != CIRCUIT_PURPOSE_INTRO_POINT)) { - return false; + goto disallow; } /* This is called just after we got a valid and parsed INTRODUCE1 cell. The @@ -189,7 +192,18 @@ hs_dos_can_send_intro2(or_circuit_t *s_intro_circ) } /* Finally, we can send a new INTRODUCE2 if there are still tokens. */ - return token_bucket_ctr_get(&s_intro_circ->introduce2_bucket) > 0; + if (token_bucket_ctr_get(&s_intro_circ->introduce2_bucket) > 0) { + goto allow; + } + + /* Fallthrough is to disallow since this means the bucket has reached 0. */ + disallow: + /* Increment stats counter, we are rejecting the INTRO2 cell. */ + intro2_rejected_count++; + return false; + + allow: + return true; } /* Initialize the onion service Denial of Service subsystem. */