Update the beacon and state network content key prefixes

The Portal specifications were adjusted so that the content key
prefixes become unique selectors over all networks.

Fixes issue #1924

SSZ Union is still used, but it could be that in the future we
need to move to our own custom serialization here.

The unused enum value and the fact that we have to add these to
the case of is quite annoying but unless we stop using a case
object seems not avoidable.

fluffy/network/beacon/beacon_content.nim

@@ -1,4 +1,4 @@
-# Nimbus - Portal Network
+# Fluffy - Portal Network
 # Copyright (c) 2022-2023 Status Research & Development GmbH
 # Licensed and distributed under either of
 #   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
@@ -30,10 +30,12 @@ const
 
 type
   ContentType* = enum
-    lightClientBootstrap = 0x00
-    lightClientUpdate = 0x01
-    lightClientFinalityUpdate = 0x02
-    lightClientOptimisticUpdate = 0x03
+    # Note: See same note as for state_content.nim
+    unused = 0x00
+    lightClientBootstrap = 0x10
+    lightClientUpdate = 0x11
+    lightClientFinalityUpdate = 0x12
+    lightClientOptimisticUpdate = 0x13
 
   # TODO: Consider how we will gossip bootstraps?
   # In consensus light client operation a node trusts only one bootstrap hash,
@@ -59,6 +61,8 @@ type
 
   ContentKey* = object
     case contentType*: ContentType
+    of unused:
+      discard
     of lightClientBootstrap:
       lightClientBootstrapKey*: LightClientBootstrapKey
     of lightClientUpdate:
@@ -84,8 +88,17 @@ func forkDigestAtEpoch*(
   forkDigests.atEpoch(epoch, cfg)
 
 func encode*(contentKey: ContentKey): ByteList =
+  doAssert(contentKey.contentType != unused)
   ByteList.init(SSZ.encode(contentKey))
 
+proc readSszBytes*(
+    data: openArray[byte], val: var ContentKey) {.raises: [SszError].} =
+  mixin readSszValue
+  if data.len() > 0 and data[0] == ord(unused):
+    raise newException(MalformedSszError, "SSZ selector unused value")
+
+  readSszValue(data, val)
+
 func decode*(contentKey: ByteList): Opt[ContentKey] =
   try:
     Opt.some(SSZ.decode(contentKey.asSeq(), ContentKey))

fluffy/network/beacon/beacon_db.nim

@@ -253,6 +253,8 @@ proc createGetHandler*(db: BeaconDb): DbGetHandler =
         return Opt.none(seq[byte])
 
       case contentKey.contentType:
+      of unused:
+        raiseAssert "Should not be used and fail at decoding"
       of lightClientBootstrap:
         db.get(contentId)
       of lightClientUpdate:
@@ -309,6 +311,8 @@ proc createStoreHandler*(db: BeaconDb): DbStoreHandler =
       return
 
     case contentKey.contentType:
+    of unused:
+      raiseAssert "Should not be used and fail at decoding"
     of lightClientBootstrap:
       db.put(contentId, content)
     of lightClientUpdate:

fluffy/network/beacon/beacon_network.nim

@@ -192,6 +192,8 @@ proc validateContent(
     return err("Error decoding content key")
 
   case key.contentType:
+  of unused:
+    raiseAssert "Should not be used and fail at decoding"
   of lightClientBootstrap:
     let decodingResult = decodeLightClientBootstrapForked(
       n.forkDigests, content)

fluffy/network/state/state_content.nim

@@ -1,4 +1,4 @@
-# Nimbus
+# Fluffy
 # Copyright (c) 2021-2023 Status Research & Development GmbH
 # Licensed and distributed under either of
 #   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
@@ -23,11 +23,19 @@ type
   Address* = array[20, byte]
 
   ContentType* = enum
-    accountTrieNode = 0x00
-    contractStorageTrieNode = 0x01
-    accountTrieProof = 0x02
-    contractStorageTrieProof = 0x03
-    contractBytecode = 0x04
+    # Note: Need to add this unused value as a case object with an enum without
+    # a 0 valueis not allowed: "low(contentType) must be 0 for discriminant".
+    # For prefix values that are in the enum gap, the deserialization will fail
+    # at runtime as is wanted.
+    # In the future it might be possible that this will fail at compile time for
+    # the SSZ Union type, but currently it is allowed in the implementation, and
+    # the SSZ spec is not explicit about disallowing this.
+    unused = 0x00
+    accountTrieNode = 0x20
+    contractStorageTrieNode = 0x21
+    accountTrieProof = 0x22
+    contractStorageTrieProof = 0x23
+    contractBytecode = 0x24
 
   AccountTrieNodeKey* = object
     path*: ByteList
@@ -55,6 +63,8 @@ type
 
   ContentKey* = object
     case contentType*: ContentType
+    of unused:
+      discard
     of accountTrieNode:
       accountTrieNodeKey*: AccountTrieNodeKey
     of contractStorageTrieNode:
@@ -67,8 +77,18 @@ type
       contractBytecodeKey*: ContractBytecodeKey
 
 func encode*(contentKey: ContentKey): ByteList =
+  doAssert(contentKey.contentType != unused)
   ByteList.init(SSZ.encode(contentKey))
 
+proc readSszBytes*(
+    data: openArray[byte], val: var ContentKey
+) {.raises: [SszError].} =
+  mixin readSszValue
+  if data.len() > 0 and data[0] == ord(unused):
+    raise newException(MalformedSszError, "SSZ selector is unused value")
+
+  readSszValue(data, val)
+
 func decode*(contentKey: ByteList): Opt[ContentKey] =
   try:
     Opt.some(SSZ.decode(contentKey.asSeq(), ContentKey))
@@ -84,6 +104,8 @@ template computeContentId*(digestCtxType: type, body: untyped): ContentId =
 
 func toContentId*(contentKey: ContentKey): ContentId =
   case contentKey.contentType:
+  of unused:
+    raiseAssert "Should not be used and fail at decoding"
   of accountTrieNode: # sha256(path | node_hash)
     let key = contentKey.accountTrieNodeKey
     computeContentId sha256:

fluffy/tests/beacon_network_tests/test_beacon_content.nim

@@ -281,3 +281,28 @@ suite "Beacon Content Encodings":
       decodeLightClientBootstrapForked(forkDigests, @[]).isErr()
       decodeLightClientBootstrapForked(forkDigests, encodedTooEarlyFork).isErr()
       decodeLightClientBootstrapForked(forkDigests, encodedUnknownFork).isErr()
+
+suite "Beacon ContentKey Encodings ":
+  test "Invalid prefix - 0 value":
+    let encoded =  ByteList.init(@[byte 0x00])
+    let decoded = decode(encoded)
+
+    check decoded.isNone()
+
+  test "Invalid prefix - before valid range":
+    let encoded = ByteList.init(@[byte 0x01])
+    let decoded = decode(encoded)
+
+    check decoded.isNone()
+
+  test "Invalid prefix - after valid range":
+    let encoded = ByteList.init(@[byte 0x14])
+    let decoded = decode(encoded)
+
+    check decoded.isNone()
+
+  test "Invalid key - empty input":
+    let encoded = ByteList.init(@[])
+    let decoded = decode(encoded)
+
+    check decoded.isNone()

fluffy/tests/portal_spec_tests/mainnet/test_state_content.nim

@@ -1,5 +1,5 @@
-# Nimbus
-# Copyright (c) 2021-2022 Status Research & Development GmbH
+# Fluffy
+# Copyright (c) 2021-2023 Status Research & Development GmbH
 # Licensed and distributed under either of
 #   * MIT license (license terms in the root directory or at https://opensource.org/licenses/MIT).
 #   * Apache v2 license (license terms in the root directory or at https://www.apache.org/licenses/LICENSE-2.0).
@@ -31,7 +31,7 @@ suite "State ContentKey Encodings":
 
     # Output
       contentKeyHex =
-        "0044000000b8be7903aee73b8f6a59cd44a1f52c62148e1f376c0dfa1f5f773a98666efc2bd1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d01020001"
+        "2044000000b8be7903aee73b8f6a59cd44a1f52c62148e1f376c0dfa1f5f773a98666efc2bd1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d01020001"
       contentId =
         "41237096982860596884042712109427867048220765019203857308279863638242761605893"
       # or
@@ -67,7 +67,7 @@ suite "State ContentKey Encodings":
 
     # Output
       contentKeyHex =
-        "01829bd824b016326a401d083b33d092293333a830580000003e190b68719aecbcb28ed2271014dd25f2aa633184988eb414189ce0899cade5d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d01000f0e0c00"
+        "21829bd824b016326a401d083b33d092293333a830580000003e190b68719aecbcb28ed2271014dd25f2aa633184988eb414189ce0899cade5d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d01000f0e0c00"
       contentId =
         "43529358882110548041037387588279806363134301284609868141745095118932570363585"
       # or
@@ -100,7 +100,7 @@ suite "State ContentKey Encodings":
     # Output
     const
       contentKeyHex =
-        "02829bd824b016326a401d083b33d092293333a830d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d"
+        "22829bd824b016326a401d083b33d092293333a830d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d"
       contentId =
         "45301550050471302973396879294932122279426162994178563319590607565171451545101"
       # or
@@ -135,7 +135,7 @@ suite "State ContentKey Encodings":
 
     # Output
       contentKeyHex =
-        "03829bd824b016326a401d083b33d092293333a830c8a6030000000000000000000000000000000000000000000000000000000000d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d"
+        "23829bd824b016326a401d083b33d092293333a830c8a6030000000000000000000000000000000000000000000000000000000000d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d"
       contentId =
         "80413803151602881485894828440259195604313253842905231566803078625935967002376"
       # or
@@ -172,7 +172,7 @@ suite "State ContentKey Encodings":
     # Output
     const
       contentKeyHex =
-        "04829bd824b016326a401d083b33d092293333a830d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d"
+        "24829bd824b016326a401d083b33d092293333a830d1c390624d3bd4e409a61a858e5dcc5517729a9170d014a6c96530d64dd8621d"
       contentId =
         "9243655320250466575533858917172702581481192615849913473767356296630272634800"
       # or
@@ -199,3 +199,27 @@ suite "State ContentKey Encodings":
       toContentId(contentKey) == parse(contentId, StUint[256], 10)
       # In stint this does BE hex string
       toContentId(contentKey).toHex() == contentIdHexBE
+
+  test "Invalid prefix - 0 value":
+    let encoded =  ByteList.init(@[byte 0x00])
+    let decoded = decode(encoded)
+
+    check decoded.isNone()
+
+  test "Invalid prefix - before valid range":
+    let encoded = ByteList.init(@[byte 0x01])
+    let decoded = decode(encoded)
+
+    check decoded.isNone()
+
+  test "Invalid prefix - after valid range":
+    let encoded = ByteList.init(@[byte 0x25])
+    let decoded = decode(encoded)
+
+    check decoded.isNone()
+
+  test "Invalid key - empty input":
+    let encoded = ByteList.init(@[])
+    let decoded = decode(encoded)
+
+    check decoded.isNone()