Merge branch 'maint-0.2.6' into release-0.2.6

This commit is contained in:
Nick Mathewson 2015-04-03 09:52:57 -04:00
commit b3f24b5de3
5 changed files with 27 additions and 1 deletions

5
changes/bug11447 Normal file
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@ -0,0 +1,5 @@
o Minor features (DoS-resistance):
- Decrease the amount of reattempts that a hidden service is
willing to perform when its rendezvous circuits fail. This
reduces the computational cost for hidden service under heavy
load. Resolves ticket #11447.

4
changes/bug15515 Normal file
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@ -0,0 +1,4 @@
o Minor features (DoS-resistance):
- Make it harder for attackers to overwhelm hidden services with
introductions, by blocking multiple introduction requests on the
same circuit. Resolves ticket #15515.

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@ -3181,6 +3181,9 @@ typedef struct or_circuit_t {
* to the specification? */ * to the specification? */
unsigned int remaining_relay_early_cells : 4; unsigned int remaining_relay_early_cells : 4;
/* We have already received an INTRODUCE1 cell on this circuit. */
unsigned int already_received_introduce1 : 1;
/** True iff this circuit was made with a CREATE_FAST cell. */ /** True iff this circuit was made with a CREATE_FAST cell. */
unsigned int is_first_hop : 1; unsigned int is_first_hop : 1;

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@ -149,6 +149,20 @@ rend_mid_introduce(or_circuit_t *circ, const uint8_t *request,
goto err; goto err;
} }
/* We have already done an introduction on this circuit but we just
received a request for another one. We block it since this might
be an attempt to DoS a hidden service (#15515). */
if (circ->already_received_introduce1) {
log_fn(LOG_PROTOCOL_WARN, LD_REND,
"Blocking multiple introductions on the same circuit. "
"Someone might be trying to attack a hidden service through "
"this relay.");
circuit_mark_for_close(TO_CIRCUIT(circ), END_CIRC_REASON_TORPROTOCOL);
return -1;
}
circ->already_received_introduce1 = 1;
/* We could change this to MAX_HEX_NICKNAME_LEN now that 0.0.9.x is /* We could change this to MAX_HEX_NICKNAME_LEN now that 0.0.9.x is
* obsolete; however, there isn't much reason to do so, and we're going * obsolete; however, there isn't much reason to do so, and we're going
* to revise this protocol anyway. * to revise this protocol anyway.

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@ -90,7 +90,7 @@ typedef struct rend_service_port_config_t {
#define MAX_INTRO_CIRCS_PER_PERIOD 10 #define MAX_INTRO_CIRCS_PER_PERIOD 10
/** How many times will a hidden service operator attempt to connect to /** How many times will a hidden service operator attempt to connect to
* a requested rendezvous point before giving up? */ * a requested rendezvous point before giving up? */
#define MAX_REND_FAILURES 8 #define MAX_REND_FAILURES 1
/** How many seconds should we spend trying to connect to a requested /** How many seconds should we spend trying to connect to a requested
* rendezvous point before giving up? */ * rendezvous point before giving up? */
#define MAX_REND_TIMEOUT 30 #define MAX_REND_TIMEOUT 30