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log: Add rate limiting to LogPrintf, LogInfo, LogWarning, LogError, LogPrintLevel

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To mitigate disk-filling attacks caused by unsafe usages of LogPrintf and
friends, we rate-limit them by passing a should_ratelimit bool that
eventually makes its way to LogPrintStr which may call
LogRateLimiter::Consume. The rate limiting is accomplished by
adding a LogRateLimiter member to BCLog::Logger which tracks source
code locations for the given logging window.

Every hour, a source location can log up to 1MiB of data. Source
locations that exceed the limit will have their logs suppressed for the
rest of the window determined by m_limiter.

This change affects the public LogPrintLevel function if called with
a level >= BCLog::Level::Info.

The UpdateTipLog function has been changed to use the private LogPrintLevel_
macro with should_ratelimit set to false. This allows UpdateTipLog to log
during IBD without hitting the rate limit.

Note that on restart, a source location that was rate limited before the
restart will be able to log until it hits the rate limit again.

Co-Authored-By: Niklas Gogge <n.goeggi@gmail.com>
Co-Authored-By: stickies-v <stickies-v@protonmail.com>
This commit is contained in:
Eugene Siegel
2025-06-05 13:42:03 -04:00
parent a6a35cc0c2
commit d541409a64
5 changed files with 181 additions and 31 deletions
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35
src/logging.cpp
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@@ -75,7 +75,7 @@ bool BCLog::Logger::StartLogging()
// dump buffered messages from before we opened the log
m_buffering = false;
if (m_buffer_lines_discarded > 0) {
LogPrintStr_(strprintf("Early logging buffer overflowed, %d log lines discarded.\n", m_buffer_lines_discarded), std::source_location::current(), BCLog::ALL, Level::Info);
LogPrintStr_(strprintf("Early logging buffer overflowed, %d log lines discarded.\n", m_buffer_lines_discarded), std::source_location::current(), BCLog::ALL, Level::Info, /*should_ratelimit=*/false);
}
while (!m_msgs_before_open.empty()) {
const auto& buflog = m_msgs_before_open.front();
@@ -412,13 +412,14 @@ void BCLog::Logger::FormatLogStrInPlace(std::string& str, BCLog::LogFlags catego
str.insert(0, LogTimestampStr(now, mocktime));
}
void BCLog::Logger::LogPrintStr(std::string_view str, std::source_location&& source_loc, BCLog::LogFlags category, BCLog::Level level)
void BCLog::Logger::LogPrintStr(std::string_view str, std::source_location&& source_loc, BCLog::LogFlags category, BCLog::Level level, bool should_ratelimit)
{
StdLockGuard scoped_lock(m_cs);
return LogPrintStr_(str, std::move(source_loc), category, level);
return LogPrintStr_(str, std::move(source_loc), category, level, should_ratelimit);
}
void BCLog::Logger::LogPrintStr_(std::string_view str, std::source_location&& source_loc, BCLog::LogFlags category, BCLog::Level level)
// NOLINTNEXTLINE(misc-no-recursion)
void BCLog::Logger::LogPrintStr_(std::string_view str, std::source_location&& source_loc, BCLog::LogFlags category, BCLog::Level level, bool should_ratelimit)
{
std::string str_prefixed = LogEscapeMessage(str);
@@ -451,6 +452,28 @@ void BCLog::Logger::LogPrintStr_(std::string_view str, std::source_location&& so
}
FormatLogStrInPlace(str_prefixed, category, level, source_loc, util::ThreadGetInternalName(), SystemClock::now(), GetMockTime());
bool ratelimit{false};
if (should_ratelimit && m_limiter) {
auto status{m_limiter->Consume(source_loc, str_prefixed)};
if (status == BCLog::LogRateLimiter::Status::NEWLY_SUPPRESSED) {
// NOLINTNEXTLINE(misc-no-recursion)
LogPrintStr_(strprintf(
"Excessive logging detected from %s:%d (%s): >%d bytes logged during "
"the last time window of %is. Suppressing logging to disk from this "
"source location until time window resets. Console logging "
"unaffected. Last log entry.\n",
source_loc.file_name(), source_loc.line(), source_loc.function_name(),
m_limiter->m_max_bytes,
Ticks<std::chrono::seconds>(m_limiter->m_reset_window)),
std::source_location::current(), LogFlags::ALL, Level::Warning, /*should_ratelimit=*/false); // with should_ratelimit=false, this cannot lead to infinite recursion
}
ratelimit = status == BCLog::LogRateLimiter::Status::STILL_SUPPRESSED;
// To avoid confusion caused by dropped log messages when debugging an issue,
// we prefix log lines with "[*]" when there are any suppressed source locations.
if (m_limiter->SuppressionsActive()) {
str_prefixed.insert(0, "[*] ");
}
}
if (m_print_to_console) {
// print to console
@@ -460,7 +483,7 @@ void BCLog::Logger::LogPrintStr_(std::string_view str, std::source_location&& so
for (const auto& cb : m_print_callbacks) {
cb(str_prefixed);
}
if (m_print_to_file) {
if (m_print_to_file && !ratelimit) {
assert(m_fileout != nullptr);
// reopen the log file, if requested
@@ -530,7 +553,7 @@ void BCLog::LogRateLimiter::Reset()
uint64_t dropped_bytes{counter.GetDroppedBytes()};
if (dropped_bytes == 0) continue;
LogPrintLevel_(
LogFlags::ALL, Level::Info,
LogFlags::ALL, Level::Info, /*should_ratelimit=*/false,
"Restarting logging from %s:%d (%s): %d bytes were dropped during the last %ss.\n",
source_loc.file_name(), source_loc.line(), source_loc.function_name(),
dropped_bytes, Ticks<std::chrono::seconds>(m_reset_window));