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Merge remote-tracking branch 'origin/maint-0.2.2' into maint-0.2.3

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Conflicts:
	src/or/routerlist.c
This commit is contained in:
Nick Mathewson
2012-08-03 12:04:11 -04:00
parent 82c5e385cb d48cebc5e4
commit 93be3a8822
2 changed files with 33 additions and 5 deletions
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changes/pathsel-BUGGY-a
+14
View File
@@ -0,0 +1,14 @@
o Security fixes:
- Try to leak less information about what relays a client is
choosing to a side-channel attacker. Previously, a Tor client
would stop iterating through the list of available relays as
soon as it had chosen one, thus finishing a little earlier
when it picked a router earlier in the list. If an attacker
can recover this timing information (nontrivial but not
proven to be impossible), they could learn some coarse-
grained information about which relays a client was picking
(middle nodes in particular are likelier to be affected than
exits). The timing attack might be mitigated by other factors
(see bug #6537 for some discussion), but it's best not to
take chances. Fixes bug 6537; bugfix on 0.0.8rc1.
src/or/routerlist.c
+19 -5
View File
@@ -1709,6 +1709,8 @@ smartlist_choose_node_by_bandwidth_weights(smartlist_t *sl,
double *bandwidths;
double tmp = 0;
unsigned int i;
unsigned int i_chosen;
unsigned int i_has_been_chosen;
int have_unknown = 0; /* true iff sl contains element not in consensus. */
/* Can't choose exit and guard at same time */
@@ -1871,12 +1873,17 @@ smartlist_choose_node_by_bandwidth_weights(smartlist_t *sl,
* from 1 below. See bug 1203 for details. */
/* Last, count through sl until we get to the element we picked */
i_chosen = (unsigned)smartlist_len(sl);
i_has_been_chosen = 0;
tmp = 0.0;
for (i=0; i < (unsigned)smartlist_len(sl); i++) {
tmp += bandwidths[i];
if (tmp >= rand_bw)
break;
if (tmp >= rand_bw && !i_has_been_chosen) {
i_chosen = i;
i_has_been_chosen = 1;
}
}
i = i_chosen;
if (i == (unsigned)smartlist_len(sl)) {
/* This was once possible due to round-off error, but shouldn't be able
@@ -1909,7 +1916,9 @@ static const node_t *
smartlist_choose_node_by_bandwidth(smartlist_t *sl,
bandwidth_weight_rule_t rule)
{
unsigned i;
unsigned int i;
unsigned int i_chosen;
unsigned int i_has_been_chosen;
int32_t *bandwidths;
int is_exit;
int is_guard;
@@ -2109,6 +2118,8 @@ smartlist_choose_node_by_bandwidth(smartlist_t *sl,
/* Last, count through sl until we get to the element we picked */
tmp = 0;
i_chosen = (unsigned)smartlist_len(sl);
i_has_been_chosen = 0;
for (i=0; i < (unsigned)smartlist_len(sl); i++) {
is_exit = bitarray_is_set(exit_bits, i);
is_guard = bitarray_is_set(guard_bits, i);
@@ -2123,9 +2134,12 @@ smartlist_choose_node_by_bandwidth(smartlist_t *sl,
else
tmp += bandwidths[i];
if (tmp >= rand_bw)
break;
if (tmp >= rand_bw && !i_has_been_chosen) {
i_chosen = i;
i_has_been_chosen = 1;
}
}
i = i_chosen;
if (i == (unsigned)smartlist_len(sl)) {
/* This was once possible due to round-off error, but shouldn't be able
* to occur any longer. */