diff --git a/contracts/wallet_v5.fc b/contracts/wallet_v5.fc index 637b345..7308ed5 100644 --- a/contracts/wallet_v5.fc +++ b/contracts/wallet_v5.fc @@ -231,15 +231,23 @@ cell verify_actions(cell c5) inline { var stored_subwallet = ds~load_uint(size::stored_subwallet); var public_key = ds.preload_uint(size::public_key); + ;; Note on bouncing/nonbouncing behaviour: + ;; In principle, the wallet should not bounce incoming messages as to avoid + ;; returning deposits back to the sender due to opcode misinterpretation. + ;; However, specifically for "gasless" transactions (signed messages relayed by a 3rd party), + ;; there is a risk for the relaying party to be abused: their coins should be bounced back in case of a race condition or delays. + ;; We resolve this dilemma by silently failing at the signature check (therefore ordinary deposits with arbitrary opcodes never bounce), + ;; but failing with exception (therefore bouncing) after the signature check. + ;; TODO: Consider moving signed into separate ref, slice_hash consumes 500 gas just like cell creation! ;; Only such checking order results in least amount of gas return_unless(check_signature(slice_hash(signed), signature, public_key)); ;; If public key is disabled, stored_seqno is strictly less than zero: stored_seqno < 0 ;; However, msg_seqno is uint, therefore it can be only greater or equal to zero: msg_seqno >= 0 ;; Thus, if public key is disabled, these two domains NEVER intersect, and additional check is not needed - return_unless(msg_seqno == stored_seqno); - return_unless(subwallet_id == stored_subwallet); - return_if(valid_until <= now()); + throw_unless(msg_seqno == stored_seqno); + throw_unless(subwallet_id == stored_subwallet); + throw_if(valid_until <= now()); ;; Store and commit the seqno increment to prevent replays even if the subsequent requests fail. stored_seqno = stored_seqno + 1; @@ -337,4 +345,4 @@ cell get_extensions() method_id { int get_is_signature_auth_allowed() method_id { return get_data().begin_parse().preload_int(size::stored_seqno) >= 0; -} \ No newline at end of file +}