fix: add some checks on disclosed indexes array

src/lua/crypto_bbs.lua

@@ -644,16 +644,19 @@ local function core_proof_gen(ciphersuite, pk, signature, generators, header, ph
  local signature_result = octets_to_signature(signature)
  local AA, e = table.unpack(signature_result)
  local undisclosed_indexes = {}
+ local disclosed_messages = {}
+ local undisclosed_messages = {}
+ for i, v in ipairs(disclosed_indexes) do
+ if i > 1 and disclosed_indexes[i] == disclosed_indexes[i - 1] then
+ error('disclosed indexes contains duplicates', 3)
+ end
+ table.insert(disclosed_messages, messages[v])
+ end
  for i = 1, L do
  if not array_contains(disclosed_indexes, i) then
  table.insert(undisclosed_indexes, i)
  end
  end
- local disclosed_messages = {}
- local undisclosed_messages = {}
- for _,v in ipairs(disclosed_indexes) do
- table.insert(disclosed_messages, messages[v])
- end
  for _,v in ipairs(undisclosed_indexes) do
  table.insert(undisclosed_messages, messages[v])
  end
@@ -679,6 +682,7 @@ function bbs.proof_gen(ciphersuite, pk, signature, header, ph, messages, disclos
  header = header or O.empty()
  ph = ph or O.empty()
  table.sort(disclosed_indexes) -- make sure indexes are sorted
+ if (disclosed_indexes[1] <= 0 or disclosed_indexes[#disclosed_indexes] > #messages) then error('disclosed indexes contains not valid integers', 2) end
  local messages = bbs.messages_to_scalars(ciphersuite,messages)
  local generators = bbs.create_generators(ciphersuite, table_size(messages) + 1)
  local proof = core_proof_gen(ciphersuite, pk, signature, generators, header, ph, messages, disclosed_indexes)
@@ -830,7 +834,14 @@ function bbs.proof_verify(ciphersuite, pk, proof, header, ph, disclosed_messages
  disclosed_indexes = disclosed_indexes or {}
  local len_U = math.floor((#proof-proof_len_floor)/OCTET_SCALAR_LENGTH)
  local len_R = table_size(disclosed_indexes)
-
+ if (disclosed_indexes[1] <= 0 or disclosed_indexes[#disclosed_indexes] > len_U + len_R) then
+ error('disclosed indexes contains not valid integers', 2)
+ end
+ for i = 2, len_R, 1 do
+ if disclosed_indexes[i] == disclosed_indexes[i - 1] then
+ error('disclosed indexes contains duplicates', 2)
+ end
+ end
  local message_scalars = bbs.messages_to_scalars(ciphersuite, disclosed_messages_octets)
  local generators = bbs.create_generators(ciphersuite, len_U+len_R+1)