core/signverify: add failsafe for an empty message header

4 years ago · 981d079d7f
parent 56fe5adcfc
commit 981d079d7f
1 changed files with 2 additions and 0 deletions
--- a/core/src/apps/common/signverify.py
+++ b/core/src/apps/common/signverify.py
@ -18,6 +18,8 @@ def message_digest(coin: CoinType, message: bytes) -> bytes:
        h = utils.HashWriter(blake256())
    else:
        h = utils.HashWriter(sha256())
+    if not coin.signed_message_header:
+        raise wire.DataError("Empty message header not allowed.")
    write_bitcoin_varint(h, len(coin.signed_message_header))
    h.extend(coin.signed_message_header)
    write_bitcoin_varint(h, len(message))