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Merge remote-tracking branch 'public/bug12169_relay_check'

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This commit is contained in:
Nick Mathewson 2014-06-04 15:30:43 -04:00
commit 95d47a7481
2 changed files with 10 additions and 5 deletions
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5
changes/bug12169_simple Normal file
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@ -0,0 +1,5 @@
o Minor bugfixes (performance):
- Avoid using tor_memeq() for checking relay cell integrity.
This removes a possible performance bottleneck. Fixes part of bug
12169; bugfix on 0.2.1.31.

10
src/or/relay.c
View file

@ -111,14 +111,14 @@ relay_set_digest(crypto_digest_t *digest, cell_t *cell)
static int
relay_digest_matches(crypto_digest_t *digest, cell_t *cell)
{
char received_integrity[4], calculated_integrity[4];
uint32_t received_integrity, calculated_integrity;
relay_header_t rh;
crypto_digest_t *backup_digest=NULL;
backup_digest = crypto_digest_dup(digest);
relay_header_unpack(&rh, cell->payload);
memcpy(received_integrity, rh.integrity, 4);
memcpy(&received_integrity, rh.integrity, 4);
memset(rh.integrity, 0, 4);
relay_header_pack(cell->payload, &rh);
@ -127,15 +127,15 @@ relay_digest_matches(crypto_digest_t *digest, cell_t *cell)
// received_integrity[2], received_integrity[3]);
crypto_digest_add_bytes(digest, (char*) cell->payload, CELL_PAYLOAD_SIZE);
crypto_digest_get_digest(digest, calculated_integrity, 4);
crypto_digest_get_digest(digest, (char*) &calculated_integrity, 4);
if (tor_memneq(received_integrity, calculated_integrity, 4)) {
if (calculated_integrity != received_integrity) {
// log_fn(LOG_INFO,"Recognized=0 but bad digest. Not recognizing.");
// (%d vs %d).", received_integrity, calculated_integrity);
/* restore digest to its old form */
crypto_digest_assign(digest, backup_digest);
/* restore the relay header */
memcpy(rh.integrity, received_integrity, 4);
memcpy(rh.integrity, &received_integrity, 4);
relay_header_pack(cell->payload, &rh);
crypto_digest_free(backup_digest);
return 0;