highperfocused/bitcoin
1
0
Fork 0
mirror of https://github.com/bitcoin/bitcoin.git synced 2025-11-11 22:50:59 +01:00
Code Issues Packages Projects Releases Wiki Activity

Merge #18991: Cache responses to GETADDR to prevent topology leaks

Browse Source 
3bd67ba5a4 Test addr response caching (Gleb Naumenko)
cf1569e074 Add addr permission flag enabling non-cached addr sharing (Gleb Naumenko)
acd6135b43 Cache responses to addr requests (Gleb Naumenko)
7cc0e8101f Remove useless 2500 limit on AddrMan queries (Gleb Naumenko)
ded742bc5b Move filtering banned addrs inside GetAddresses() (Gleb Naumenko)

Pull request description:

  This is a very simple code change with a big p2p privacy benefit.

  It’s currently trivial to scrape any reachable node’s AddrMan (a database of all nodes known to them along with the timestamps).
  We do have a limit of one GETADDR per connection, but a spy can disconnect and reconnect even from the same IP, and send GETADDR again and again.

  Since we respond with 1,000 random records at most, depending on the AddrMan size it takes probably up to 100 requests for an spy to make sure they scraped (almost) everything.
  I even have a script for that. It is totally doable within couple minutes.

  Then, with some extra protocol knowledge a spy can infer the direct peers of the victim, and other topological stuff.

  I suggest to cache responses to GETADDR on a daily basis, so that an attacker gets at most 1,000 records per day, and can’t track the changes in real time. I will be following up with more improvements to addr relay privacy, but this one alone is a very effective. And simple!

  I doubt any of the real software does *reconnect to get new addrs from a given peer*, so we shouldn’t be cutting anyone.
  I also believe it doesn’t have any negative implications on the overall topology quality. And the records being “outdated” for at most a day doesn’t break any honest assumptions either.

ACKs for top commit:
  jnewbery:
    reACK 3bd67ba5a4
  promag:
    Code review ACK 3bd67ba5a4.
  ariard:
    Code Review ACK 3bd67ba

Tree-SHA512: dfa5d03205c2424e40a3f8a41af9306227e1ca18beead3b3dda44aa2a082175bb1c6d929dbc7ea8e48e01aed0d50f0d54491caa1147471a2b72a46c3ca06b66f
This commit is contained in:
Wladimir J. van der Laan
2020-08-03 14:04:05 +02:00
parent a78742830a 3bd67ba5a4
commit 14ceddd290
11 changed files with 183 additions and 13 deletions
Download Patch File Download Diff File Expand all files Collapse all files

3
src/test/netbase_tests.cpp
View File

@@ -406,13 +406,14 @@ BOOST_AUTO_TEST_CASE(netpermissions_test)
BOOST_CHECK(NetWhitelistPermissions::TryParse("bloom,forcerelay,noban,relay,mempool@1.2.3.4/32", whitelistPermissions, error));
const auto strings = NetPermissions::ToStrings(PF_ALL);
BOOST_CHECK_EQUAL(strings.size(), 6U);
BOOST_CHECK_EQUAL(strings.size(), 7U);
BOOST_CHECK(std::find(strings.begin(), strings.end(), "bloomfilter") != strings.end());
BOOST_CHECK(std::find(strings.begin(), strings.end(), "forcerelay") != strings.end());
BOOST_CHECK(std::find(strings.begin(), strings.end(), "relay") != strings.end());
BOOST_CHECK(std::find(strings.begin(), strings.end(), "noban") != strings.end());
BOOST_CHECK(std::find(strings.begin(), strings.end(), "mempool") != strings.end());
BOOST_CHECK(std::find(strings.begin(), strings.end(), "download") != strings.end());
BOOST_CHECK(std::find(strings.begin(), strings.end(), "addr") != strings.end());
}
BOOST_AUTO_TEST_CASE(netbase_dont_resolve_strings_with_embedded_nul_characters)