There are a few reasons that relays might be uploading desciptors
without saying X-Desc-Gen-Reason:
1. They are running an old version of our software, before 0.3.2.stable.
2. They are not running our software, but they are claiming they
are.
3. They are uploading through a proxy that strips X-Desc-Gen-Reason.
4. They somehow had a bug in their software.
According to the 25686 data, 1 is the most common reason. This
ticket is an attempt to diagnose case 4, or prove that case 4
doesn't actually happen.
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
The specification describes the signature token to be right after a newline
(\n) then the token "signature" and then a white-space followed by the encoded
signature.
This commit makes sure that when we parse the signature from the descriptor,
we are always looking for that extra white-space at the end of the token.
It will allow us also to support future fields that might start with
"signature".
Fixes#26069
Signed-off-by: David Goulet <dgoulet@torproject.org>
The any_client_port_set() returns true if the ControlPort is set which is
wrong because we can have that port open but still not behave as a tor client
(like many relays for instance).
Fixes#26062
Signed-off-by: David Goulet <dgoulet@torproject.org>
Remove v3 optimization which made Tor not detect disabling services.
This optimization is not so needed because we only call that function after HUP
anyway.
Fixes bug #25761.
During service configuration, rend_service_prune_list_impl_() sets
rend_service_staging_list to NULL, which blocked pruning after a HUP.
This patch initializes rend_service_staging_list when needed, so that HUP can
detect disabled onion services.
Fixes bug #25761.
When directory authorities read a zero-byte bandwidth file, they log
a warning with the contents of an uninitialised buffer. Log a warning
about the empty file instead.
Fixes bug 26007; bugfix on 0.2.2.1-alpha.
Prior to #23100, we were not counting HS circuit build times in our
calculation of the timeout. This could lead to a condition where our timeout
was set too low, based on non HS circuit build times, and then we would
abandon all HS circuits, storing no valid timeouts in the histogram.
This commit avoids the assert.
