In protover.c, the `expand_protocol_list()` function expands a `smartlist_t` of
`proto_entry_t`s to their protocol name concatenated with each version number.
For example, given a `proto_entry_t` like so:
proto_entry_t *proto = tor_malloc(sizeof(proto_entry_t));
proto_range_t *range = tor_malloc_zero(sizeof(proto_range_t));
proto->name = tor_strdup("DoSaaaaaaaaaaaaaaaaaaaaaa[19KB]aaa");
proto->ranges = smartlist_new();
range->low = 1;
range->high = 65536;
smartlist_add(proto->ranges, range);
(Where `[19KB]` is roughly 19KB of `"a"` bytes.) This would expand in
`expand_protocol_list()` to a `smartlist_t` containing 65536 copies of the
string, e.g.:
"DoSaaaaaaaaaaaaaaaaaaaaaa[19KB]aaa=1"
"DoSaaaaaaaaaaaaaaaaaaaaaa[19KB]aaa=2"
[…]
"DoSaaaaaaaaaaaaaaaaaaaaaa[19KB]aaa=65535"
Thus constituting a potential resource exhaustion attack.
The Rust implementation is not subject to this attack, because it instead
expands the above string into a `HashMap<String, HashSet<u32>` prior to #24031,
and a `HashMap<UnvalidatedProtocol, ProtoSet>` after). Neither Rust version is
subject to this attack, because it only stores the `String` once per protocol.
(Although a related, but apparently of too minor impact to be usable, DoS bug
has been fixed in #24031. [0])
[0]: https://bugs.torproject.org/24031
* ADDS hard limit on protocol name lengths in protover.c and checks in
parse_single_entry() and expand_protocol_list().
* ADDS tests to ensure the bug is caught.
* FIXES#25517: https://bugs.torproject.org/25517
In protover.c, the `expand_protocol_list()` function expands a `smartlist_t` of
`proto_entry_t`s to their protocol name concatenated with each version number.
For example, given a `proto_entry_t` like so:
proto_entry_t *proto = tor_malloc(sizeof(proto_entry_t));
proto_range_t *range = tor_malloc_zero(sizeof(proto_range_t));
proto->name = tor_strdup("DoSaaaaaaaaaaaaaaaaaaaaaa[19KB]aaa");
proto->ranges = smartlist_new();
range->low = 1;
range->high = 65536;
smartlist_add(proto->ranges, range);
(Where `[19KB]` is roughly 19KB of `"a"` bytes.) This would expand in
`expand_protocol_list()` to a `smartlist_t` containing 65536 copies of the
string, e.g.:
"DoSaaaaaaaaaaaaaaaaaaaaaa[19KB]aaa=1"
"DoSaaaaaaaaaaaaaaaaaaaaaa[19KB]aaa=2"
[…]
"DoSaaaaaaaaaaaaaaaaaaaaaa[19KB]aaa=65535"
Thus constituting a potential resource exhaustion attack.
The Rust implementation is not subject to this attack, because it instead
expands the above string into a `HashMap<String, HashSet<u32>` prior to #24031,
and a `HashMap<UnvalidatedProtocol, ProtoSet>` after). Neither Rust version is
subject to this attack, because it only stores the `String` once per protocol.
(Although a related, but apparently of too minor impact to be usable, DoS bug
has been fixed in #24031. [0])
[0]: https://bugs.torproject.org/24031
* ADDS hard limit on protocol name lengths in protover.c and checks in
parse_single_entry() and expand_protocol_list().
* ADDS tests to ensure the bug is caught.
* FIXES#25517: https://bugs.torproject.org/25517
We alloc/free X.509 structures in three ways:
1) X509 structure allocated with X509_new() and X509_free()
2) Fake X509 structure allocated with fake_x509_malloc() and fake_x509_free()
May contain valid pointers inside.
3) Empty X509 structure shell allocated with tor_malloc_zero() and
freed with tor_free()
Since we're going to be disabling the second-elapsed callback, we're
going to sometimes have long periods when no events file, and so the
current second is not updated. Handle that by having a better means
to detect "clock jumps" as opposed to "being idle for a while".
Tolerate far more of the latter.
Part of #26009.
Previously the coverage on this function was mostly accidental,
coming as it did from test_entryconn.c. These new tests use mocking
to ensure that we actually hit the different failure and retry cases
of addressmap_get_virtual_address(), and make our test coverage a
bit more deterministic.
Closes ticket 25993.
Previously, an authority with a clock more than 60 seconds ahead could
cause a client with a correct clock to warn that the client's clock
was behind. Now the clocks of a majority of directory authorities
have to be ahead of the client before this warning will occur.
Relax the early-consensus check so that a client's clock must be 60
seconds behind the earliest time that a given sufficiently-signed
consensus could possibly be available.
Add a new unit test that calls warn_early_consensus() directly.
Fixes bug 25756; bugfix on 0.2.2.25-alpha.
construct_consensus() in test_routerlist.c created votes using a
timestamp from time(). Tests that called construct_consensus() might
have nondeterministic results if they rely on time() not changing too
much on two successive calls.
Neither existing of the two existing tests that calls
construct_consensus is likely to have a failure due to this problem.
Our previous algorithm had a nonzero probability of picking no
events to cancel, which is of course incorrect. The new code uses
Vitter's good old reservoir sampling "algorithm R" from 1985.
Fixes bug 26008; bugfix on 0.2.6.3-alpha.
This functionality was covered only accidentally by our voting-test
code, and as such wasn't actually tested at all. The tests that
called it made its coverage nondeterministic, depending on what time
of day you ran the tests.
Closes ticket 26014.
