If the code was compiled with newer (>=3.17) kernel headers but executed
on a system without the system call, every use of random would crash the
program. Add a fallback for that case.
Move the OS random test to a sanity check function that is called every
time bitcoind is initialized.
Keep `src/test/random_tests.cpp` for the case that later random tests
are added, and keep a rudimentary test that just calls the sanity check.
These are available in sandboxes without access to files or
devices. Also [they are safer and more straightforward](https://en.wikipedia.org/wiki/Entropy-supplying_system_calls)
to use than `/dev/urandom` as reading from a file has quite a few edge
cases:
- Linux: `getrandom(buf, buflen, 0)`. [getrandom(2)](http://man7.org/linux/man-pages/man2/getrandom.2.html)
was introduced in version 3.17 of the Linux kernel.
- OpenBSD: `getentropy(buf, buflen)`. The [getentropy(2)](http://man.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man2/getentropy.2)
function appeared in OpenBSD 5.6.
- FreeBSD and NetBSD: `sysctl(KERN_ARND)`. Not sure when this was added
but it has existed for quite a while.
Alternatives:
- Linux has sysctl `CTL_KERN` / `KERN_RANDOM` / `RANDOM_UUID`
which gives 16 bytes of randomness. This may be available
on older kernels, however [sysctl is deprecated on Linux](https://lwn.net/Articles/605392/)
and even removed in some distros so we shouldn't use it.
Add tests for `GetOSRand()`:
- Test that no error happens (otherwise `RandFailure()` which aborts)
- Test that all 32 bytes are overwritten (initialize with zeros, try multiple times)
Discussion:
- When to use these? Currently they are always used when available.
Another option would be to use them only when `/dev/urandom` is not
available. But this would mean these code paths receive less testing,
and I'm not sure there is any reason to prefer `/dev/urandom`.
Closes: #9676
* Extends -dns parameter (via fNameLookup) to control these two new
parameters in addition to -addnode, -connect, and -seednode
* Moves fNameLookup assignment earlier as needed
* Changes -proxy and -onion to use Lookup() instead of LookupNumeric()
Remove "nLowestTimestamp <= chainActive.Tip()->GetBlockTimeMax()" check from
importmulti, which is always true because nLowestTimestamp is set to the
minimum of the most recent block time and all the imported key timestamps,
which is necessarily lower than the maximum block time.
- If the -maxsigcachesize parameter is set to zero, setup a minimum sized
sigcache (2 elements) rather than segfaulting.
- Handle maxsigcachesize being negative
- Handle maxsigcachesize being too large
A new AssertLockHeld(cs_wallet) call was added in commit a58370e
"Dedup nTimeFirstKey update logic" (part of PR #9108).
The lock held assertion will fail when loading prexisting wallets files from
before the #9108 merge that have watch-only keys.
Fixes a bug in AcceptBlock() in invoking CheckBlock() with incorrect
arguments, and restores a call to CheckBlock() from ProcessNewBlock()
as belt-and-suspenders.
Updates the (overspecified) tests to match behavior.
Because it is used inconsistently at least version 5.4.0 of g++ to
complains about methods that don't use override. There is two ways to go
about this: remove override from the methods having it, or add it to the
methods missing it. I chose the second.
7a8c251901 made this logic hard to follow. After that change, messages would
not be sent to a peer via SendMessages() before the handshake was complete, but
messages could still be sent as a response to an incoming message.
For example, if a peer had not yet sent a verack, we wouldn't notify it about
new blocks, but we would respond to a PING with a PONG.
This change makes the behavior straightforward: until we've received a verack,
never send any message other than version/verack/reject.
The behavior until a VERACK is received has always been undefined, this change
just tightens our policy.
This also makes testing much easier, because we can now connect but not send
version/verack, and anything sent to us is an error.
Prior to this change, all messages were ignored until a VERSION message was
received, as well as possibly incurring a ban score.
Since REJECT messages can be sent at any time (including as a response to a bad
VERSION message), make sure to always parse them.
Moving this parsing up keeps it from being caught in the
if (pfrom->nVersion == 0) check below.
7a8c251901 made a change to avoid getting into SendMessages() until the
version handshake (VERSION + VERACK) is complete. That was done to avoid
leaking out messages to nodes who could connect, but never bothered sending
us their version/verack.
Unfortunately, the ban tally and possible disconnect are done as part of
SendMessages(). So after 7a8c251901, if a peer managed to do something
bannable before completing the handshake (say send 100 non-version messages
before their version), they wouldn't actually end up getting
disconnected/banned. That's fixed here by checking the banscore as part of
ProcessMessages() in addition to SendMessages().
When importing a watch-only address over importmulti with a specific timestamp,
the wallet's nTimeFirstKey is currently set to 1. After this change, the
provided timestamp will be used and stored as metadata associated with
watch-only key. This can improve wallet performance because it can avoid the
need to scan the entire blockchain for watch only addresses when timestamps are
provided.
Also adds timestamp to validateaddress return value (needed for tests).
Fixes#9034.
Additionally, accept a "now" timestamp, to allow avoiding rescans for keys
which are known never to have been used.
Note that the behavior when "now" is specified is slightly different than the
previous behavior when no timestamp was specified at all. Previously, when no
timestamp was specified, it would avoid rescanning during the importmulti call,
but set the key's nCreateTime value to 1, which would not prevent future block
reads in later ScanForWalletTransactions calls. With this change, passing a
"now" timestamp will set the key's nCreateTime to the current block time
instead of 1.
Fixes#9491
Wladimir J. van der Laan