Merge bitcoin/bitcoin#22146: Reject invalid coin height and output index when loading assumeutxo

fa9ebedec3 Reject invalid coin height and output index when loading assumeutxo (MarcoFalke)

Pull request description:

  It should be impossible to have a coin at a height higher than the height of the snapshot block, so reject those early to avoid integer wraparounds and hash collisions later on.

  Same for the outpoint index.

  Both issues were found by fuzzing:

  * The height issue by OSS-Fuzz: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=34793
  * The outpoint issue by my fuzz server: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=34793#c2

ACKs for top commit:
  practicalswift:
    cr ACK fa9ebedec3: patch looks correct
  jamesob:
    crACK fa9ebedec3
  theStack:
    Code review ACK fa9ebedec3
  benthecarman:
    crACK fa9ebedec3

Tree-SHA512: dae7caee4b3862b23ebdf2acb7edec4baf75b0dbf1409b370b1a73aa6b632b317ebfac596dcbaf4edfb1301b513f45465ea75328962460f35e2af0d7e547c9ac

src/validation.cpp

@@ -4879,6 +4879,14 @@ bool ChainstateManager::PopulateAndValidateSnapshot(
                       coins_count - coins_left);
             return false;
         }
+        if (coin.nHeight > base_height ||
+            outpoint.n >= std::numeric_limits<decltype(outpoint.n)>::max() // Avoid integer wrap-around in coinstats.cpp:ApplyHash
+        ) {
+            LogPrintf("[snapshot] bad snapshot data after deserializing %d coins\n",
+                      coins_count - coins_left);
+            return false;
+        }
+
         coins_cache.EmplaceCoinInternalDANGER(std::move(outpoint), std::move(coin));
 
         --coins_left;

test/sanitizer_suppressions/ubsan

@@ -34,9 +34,6 @@ unsigned-integer-overflow:crypto/
 unsigned-integer-overflow:FuzzedDataProvider.h
 unsigned-integer-overflow:hash.cpp
 unsigned-integer-overflow:leveldb/
-# temporary coinstats suppressions (will be removed and fixed in https://github.com/bitcoin/bitcoin/pull/22146)
-unsigned-integer-overflow:node/coinstats.cpp
-signed-integer-overflow:node/coinstats.cpp
 unsigned-integer-overflow:policy/fees.cpp
 unsigned-integer-overflow:prevector.h
 unsigned-integer-overflow:pubkey.h