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dos: Account rejection in hs_dos_can_send_intro2

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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>
This commit is contained in:
David Goulet 2019-10-31 13:50:36 -04:00
parent fa0257eda0
commit ff8823d03c
1 changed files with 17 additions and 3 deletions
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20
src/feature/hs/hs_dos.c
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@ -45,6 +45,9 @@
* introduction DoS defense. Disabled by default. */ * introduction DoS defense. Disabled by default. */
#define HS_DOS_INTRODUCE_ENABLED_DEFAULT 0 #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 /* Consensus parameters. The ESTABLISH_INTRO DoS cell extension have higher
* priority than these values. If no extension is sent, these are used only by * priority than these values. If no extension is sent, these are used only by
* the introduction point. */ * 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 * This can be set by the consensus, the ESTABLISH_INTRO cell extension or
* the hardcoded values in tor code. */ * the hardcoded values in tor code. */
if (!s_intro_circ->introduce2_dos_defense_enabled) { if (!s_intro_circ->introduce2_dos_defense_enabled) {
return true; goto allow;
} }
/* Should not happen but if so, scream loudly. */ /* Should not happen but if so, scream loudly. */
if (BUG(TO_CIRCUIT(s_intro_circ)->purpose != CIRCUIT_PURPOSE_INTRO_POINT)) { 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 /* 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. */ /* 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. */ /* Initialize the onion service Denial of Service subsystem. */