Require callers of AcceptBlockHeader() to perform anti-dos checks

In order to prevent memory DoS, we must ensure that we don't accept a new
header into memory until we've performed anti-DoS checks, such as verifying
that the header is part of a sufficiently high work chain. This commit adds a
new argument to AcceptBlockHeader() so that we can ensure that all call-sites
which might cause a new header to be accepted into memory have to grapple with
the question of whether the header is safe to accept, or needs further
validation.

This patch also fixes two places where low-difficulty-headers could have been
processed without such validation (processing an unrequested block from the
network, and processing a compact block).

Credit to Niklas Gögge for noticing this issue, and thanks to Sjors Provoost
for test code.

1 files changed, 5 insertions, 5 deletions

diff --git a/src/test/validation_block_tests.cpp b/src/test/validation_block_tests.cpp
index 1c5ca18759..bb1ade153a 100644
--- a/src/test/validation_block_tests.cpp
+++ b/src/test/validation_block_tests.cpp
@@ -100,7 +100,7 @@ std::shared_ptr<CBlock> MinerTestingSetup::FinalizeBlock(std::shared_ptr<CBlock>
     // submit block header, so that miner can get the block height from the
     // global state and the node has the topology of the chain
     BlockValidationState ignored;
-    BOOST_CHECK(Assert(m_node.chainman)->ProcessNewBlockHeaders({pblock->GetBlockHeader()}, ignored));
+    BOOST_CHECK(Assert(m_node.chainman)->ProcessNewBlockHeaders({pblock->GetBlockHeader()}, true, ignored));
 
     return pblock;
 }
@@ -157,7 +157,7 @@ BOOST_AUTO_TEST_CASE(processnewblock_signals_ordering)
 
     bool ignored;
     // Connect the genesis block and drain any outstanding events
-    BOOST_CHECK(Assert(m_node.chainman)->ProcessNewBlock(std::make_shared<CBlock>(Params().GenesisBlock()), true, &ignored));
+    BOOST_CHECK(Assert(m_node.chainman)->ProcessNewBlock(std::make_shared<CBlock>(Params().GenesisBlock()), true, true, &ignored));
     SyncWithValidationInterfaceQueue();
 
     // subscribe to events (this subscriber will validate event ordering)
@@ -179,13 +179,13 @@ BOOST_AUTO_TEST_CASE(processnewblock_signals_ordering)
             FastRandomContext insecure;
             for (int i = 0; i < 1000; i++) {
                 auto block = blocks[insecure.randrange(blocks.size() - 1)];
-                Assert(m_node.chainman)->ProcessNewBlock(block, true, &ignored);
+                Assert(m_node.chainman)->ProcessNewBlock(block, true, true, &ignored);
             }
 
             // to make sure that eventually we process the full chain - do it here
             for (const auto& block : blocks) {
                 if (block->vtx.size() == 1) {
-                    bool processed = Assert(m_node.chainman)->ProcessNewBlock(block, true, &ignored);
+                    bool processed = Assert(m_node.chainman)->ProcessNewBlock(block, true, true, &ignored);
                     assert(processed);
                 }
             }
@@ -224,7 +224,7 @@ BOOST_AUTO_TEST_CASE(mempool_locks_reorg)
 {
     bool ignored;
     auto ProcessBlock = [&](std::shared_ptr<const CBlock> block) -> bool {
-        return Assert(m_node.chainman)->ProcessNewBlock(block, /*force_processing=*/true, /*new_block=*/&ignored);
+        return Assert(m_node.chainman)->ProcessNewBlock(block, /*force_processing=*/true, /*min_pow_checked=*/true, /*new_block=*/&ignored);
     };
 
     // Process all mined blocks