ca2e474372 Fix a compiler warning: unused GetDevURandom() (Vasil Dimov)
Pull request description:
~~Only define GetDevURandom() if it is going to be used.~~
Silence by planting a dummy reference to the `GetDevURandom` symbol
in the places where we don't call the function.
ACKs for top commit:
practicalswift:
ACK ca2e474372 -- increased signal to noise in compiler diagnostics is good
sipa:
utACK ca2e474372
hebasto:
re-ACK ca2e474372, tested on macOS 10.15.6 + llvm clang 10.0.0
Tree-SHA512: 03c98f00dad5d9a3c5c9f68553d72ad5489ec02f18b9769108a22003ec7be7819a731b1eab6a9f64dafb5be0efddccf6980de7e3bb90cd20d4f4d72f74124675
0000ea3265 test: Add test for GetRandMillis and GetRandMicros (MarcoFalke)
fa0e5b89cf Add templated GetRandomDuration<> (MarcoFalke)
Pull request description:
A naive implementation of this template is dangerous, because the call site might accidentally omit the template parameter:
```cpp
template <typename D>
D GetRandDur(const D& duration_max)
{
return D{GetRand(duration_max.count())};
}
BOOST_AUTO_TEST_CASE(util_time_GetRandTime)
{
std::chrono::seconds rand_hour = GetRandDur(std::chrono::hours{1});
// Want seconds to be in range [0..1hour), but always get zero :((((
BOOST_CHECK_EQUAL(rand_hour.count(), 0);
}
```
Luckily `std::common_type` is already specialised in the standard lib for `std::chrono::duration` (https://en.cppreference.com/w/cpp/chrono/duration/common_type). And its effect seem to be that the call site must always specify the template argument explicitly.
So instead of implementing the function for each duration type by hand, replace it with a templated version that is safe to use.
ACKs for top commit:
laanwj:
Code review ACK 0000ea3265
promag:
Code review ACK 0000ea3265.
jonatack:
ACK 0000ea3 thanks for the improved documentation. Code review, built, ran `src/test/test_bitcoin -t random_tests -l test_suite` for the new unit tests, `git diff fa05a4c 0000ea3` since previous review:
hebasto:
ACK 0000ea3265 with non-blocking [nit](https://github.com/bitcoin/bitcoin/pull/18781#discussion_r424924671).
Tree-SHA512: e89d46e31452be6ea14269ecbbb2cdd9ae83b4412cd14dff7d1084283092722a2f847cb501e8054394e4a3eff852f9c87f6d694fd008b3f7e8458cb5a3068af7
Enable -Wconditional-uninitialized to warn on potentially uninitialized
reads.
Fix the sole such warning in Bitcoin Core in GetRdRand(): r1 would be
set to 0 on rdrand failure, so initializing it to 0 is a non-functional
change.
From "Intel 64 and IA-32 ArchitecturesSoftware Developer's Manual" [1],
page 1711: "CF=1 indicates that the data in the destination is valid.
Otherwise CF=0 and the data in the destination operand will be returned
as zeros for the specified width."
[1] https://software.intel.com/sites/default/files/managed/39/c5/325462-sdm-vol-1-2abcd-3abcd.pdf
50fc4df6c4 [mempool] Persist unbroadcast set to mempool.dat (Amiti Uttarwar)
297a178536 [test] Integration tests for unbroadcast functionality (Amiti Uttarwar)
6851502472 [refactor/test] Extract P2PTxInvStore into test framework (Amiti Uttarwar)
dc1da48dc5 [wallet] Update the rebroadcast frequency to be ~1/day. (Amiti Uttarwar)
e25e42f20a [p2p] Reattempt initial send of unbroadcast transactions (Amiti Uttarwar)
7e93eecce3 [util] Add method that returns random time in milliseconds (Amiti Uttarwar)
89eeb4a333 [mempool] Track "unbroadcast" transactions (Amiti Uttarwar)
Pull request description:
This PR introduces mempool tracking of unbroadcast transactions and periodic reattempts at initial broadcast. This is a part of the rebroadcast project, and a standalone privacy win.
The current rebroadcast logic is terrible for privacy because 1. only the source wallet rebroadcasts transactions and 2. it does so quite frequently. In the current system, if a user submits a transaction that does not immediately get broadcast to the network (eg. they are offline), this "rebroadcast" behavior is the safety net that can actually serve as the initial broadcast. So, keeping the attempts frequent is important for initial delivery within a reasonable timespan.
This PR aims to improve # 2 by reducing the wallet rebroadcast frequency to ~1/day from ~1/15 min. It achieves this by separating the notion of initial broadcast from rebroadcasts. With these changes, the mempool tracks locally submitted transactions & periodically reattempts initial broadcast. Transactions submitted via the wallet or RPC are added to an "unbroadcast" set & are removed when a peer sends a `getdata` request, or the transaction is removed from the mempool. Every 10-15 minutes, the node reattempts an initial broadcast. This enables reducing the wallet rebroadcast frequency while ensuring the transactions will be propagated to the network.
For privacy improvements around # 1, please see #16698.
Thank you to gmaxwell for the idea of how to break out this subset of functionality (https://github.com/bitcoin/bitcoin/pull/16698#issuecomment-571399346)
ACKs for top commit:
fjahr:
Code review ACK 50fc4df6c4
MarcoFalke:
ACK 50fc4df6c4, I think this is ready for merge now 👻
amitiuttarwar:
The current tip `50fc4df` currently has 6 ACKs on it, so I've opened #18807 to address the last bits.
jnewbery:
utACK 50fc4df6c4.
ariard:
Code Review ACK 50fc4df (minor points no need to invalid other ACKs)
robot-visions:
ACK 50fc4df6c4
sipa:
utACK 50fc4df6c4
naumenkogs:
utACK 50fc4df
Tree-SHA512: 2dd935d645d5e209f8abf87bfaa3ef0e4492705ce7e89ea64279cb27ffd37f4727fa94ad62d41be331177332f8edbebf3c7f4972f8cda10dd951b80a28ab3c0f
```
random.cpp:255:13: error: unused function 'GetDevURandom' [-Werror,-Wunused-function]
```
Clang 9.0.0, FreeBSD 12.1
Silence by planting a dummy reference to the `GetDevURandom` symbol
in the places where we don't call the function.
sysctl() on *BSD takes a "const int *name", whereas sysctl() on macOS
it takes an "int *name". So our configure check and sysctl() detection on
macOS currently fails:
```bash
/usr/include/sys/sysctl.h:759:9: note: candidate function not viable:
no known conversion from 'const int [2]' to 'int *' for 1st argument
int sysctl(int *, u_int, void *, size_t *, void *, size_t);
```
This change removes the name argument from the sysctl() detection check,
meaning we will detect correctly on macOS and *BSD.
For consistency we also switch to using the more generic, non-const
version of the name parameter in the rest of our usage.
55b2cb199c random: mark RandAddPeriodic and SeedPeriodic as noexcept (fanquake)
461e547877 doc: correct random.h docs after #17270 (fanquake)
Pull request description:
The usage of `MilliSleep()` in SeedPeriodic (previously SeedSleep) was
[removed](d61f2bb076) in #17270, meaning it, and its users can now be marked `noexcept`.
This also corrects the docs in random.h for some of the changes in #17270.
ACKs for top commit:
practicalswift:
ACK 55b2cb199c
laanwj:
ACK 55b2cb199c
sipa:
ACK 55b2cb199c
Tree-SHA512: 672d369796e7c4f9b4d98dc545e5454999fa1bef373871994a26041d6163c58909e2255e4f820d3ef011679aa3392754eb57477306a89f5fd3d57e2bd7f0811a
On the ::SLOW path we would use OpenSSL as an additional source of
random bytes. This commit removes that functionality. Note that this was
always only an additional source, and that we never checked the return
value
RAND_bytes(): https://www.openssl.org/docs/manmaster/man3/RAND_bytes.html
RAND_bytes() puts num cryptographically strong pseudo-random bytes into buf.
On the ::SLOW or ::SLEEP paths, we would feed our RNG output back into
OpenSSL using RAND_add. This commit removes that functionality.
RAND_add(): https://www.openssl.org/docs/manmaster/man3/RAND_add.html
RAND_add() mixes the num bytes at buf into the internal state of the
random generator. This function will not normally be needed, as
mentioned above. The randomness argument is an estimate of how much
randomness is contained in buf, in bytes, and should be a number
between zero and num.
* Instead of calling RandAddSeedSleep anytime the scheduler goes
idle, call its replacement (RandAddSeedPeriodic) just once per
minute. This has better guarantees of actually being run, and
helps limit how frequently the dynamic env data is gathered.
* Since this code runs once per minute regardless now, we no
longer need to keep track of the last time strengthening was
run; just do it always.
* Make strengthening time context dependent (100 ms at startup,
10 ms once per minute afterwards).
3cb9ce85d0 Document strenghtening (Pieter Wuille)
1d207bc46f Add hash strengthening to the RNG (Pieter Wuille)
Pull request description:
This patch improves the built-in RNG using hash strengthening.
At startup, and once every minute, 32 bytes of entropy are produced from the RNG, repeatedly hashed using SHA512 for 10ms, and then fed back into the RNG, together with high-precision timestamps obtained every 1000 iterations.
ACKs for commit 3cb9ce:
pstratem:
utACK 3cb9ce85d0
Tree-SHA512: 4fb6f61639b392697beb81c5f0903f79f10dd1087bed7f34de2abb5c22704a671e37b2d828ed141492491863efb1e7d1fa04408a1d32c9de2f2cc8ac406bbe57
1435fabc19 Use RdSeed when available, and reduce RdRand load (Pieter Wuille)
Pull request description:
This introduces support for autodetecting and using the RdSeed instruction on x86/x86_64 systems.
In addition:
* In SeedFast, only 64 bits of entropy are generated through RdRand (256 was relatively slow).
* In SeedStartup, 256 bits of entropy are generated, using RdSeed (preferably) or RdRand (otherwise).
Tree-SHA512: fb7d3e22e93e14592f4b07282aa79d7c3cc4e9debdd9978580b8d2562bbad345e289bf3f80de2c50c9b50b8bac2aa9b838f9f272f7f8d43f1efc0913aa8acce3
This introduces support for autodetecting and using the RdSeed instruction.
In addition:
* In SeedFast, only 64 bits of entropy are generated through RdRand (256 was relatively slow).
* In SeedStartup, 256 bits of entropy are generated, using RdSeed (preferably) or RdRand (otherwise).
It includes the following policy changes:
* All GetRand* functions seed the stack pointer and rdrand result
(in addition to the performance counter)
* The periodic entropy added by the idle scheduler now seeds stack pointer,
rdrand and perfmon data (once every 10 minutes) in addition to
just a sleep timing.
* The entropy added when calling GetStrongRandBytes no longer includes
the once-per-10-minutes perfmon data on windows (it is moved to the
idle scheduler instead, where latency matters less).
Other changes:
* OpenSSL is no longer seeded directly anywhere. Instead, any generated
randomness through our own RNG is fed back to OpenSSL (after an
additional hashing step to prevent leaking our RNG state).
* Seeding that was previously done directly in RandAddSeedSleep is now
moved to SeedSleep(), which is indirectly invoked through ProcRand
from RandAddSeedSleep.
* Seeding that was previously done directly in GetStrongRandBytes()
is now moved to SeedSlow(), which is indirectly invoked through
ProcRand from GetStrongRandBytes().
This guarantees that OpenSSL is initialized properly whenever randomness
is used, even when that randomness is invoked from global constructors.
Note that this patch uses Mutex directly, rather than CCriticalSection.
This is because the lock-detection code is not necessarily initialized
during global constructors.
Sebastian Falbesoner