[test] add fuzz targets for sequences of tbor commands and dispatcher - #787

Secondary CO sessions blocked by exhausted bootstrap session slots

fuzz/​fuzz_targets/​ddi/​tbor/​fuzz_tbor_app_ops.rs:61

The bootstrap session is an active Crypto-Officer session, and CO handshakes have only slot 0 available. Consequently every secondary CO SessionOpenInit reaches VaultSessionLimitReached here and immediately continues, so no finish-MAC or close operation below is ever exercised. Use the rotated CU fixture/credentials for the primary and secondary handles (CU has slots 1–7), or close the bootstrap CO and restructure the per-handle-limit check before opening secondaries.

Secondary CO session always exceeds the firmware session limit

fuzz/​fuzz_targets/​ddi/​tbor/​fuzz_tbor_app_ops.rs:61

The active bootstrap_rotated_co session already occupies the firmware's single CO slot, so this secondary CO SessionOpenInit always returns VaultSessionLimitReached (the same invariant is exercised in ddi/tbor/types/tests/commands/open_session.rs:352-372). Consequently every OpenSession operation continues here, file_handles remains empty, and none of the Phase 2 or close-session sequence logic is fuzzed. Use a session type/identity with spare capacity (for example CU), or restructure the bootstrap so the CO slot is free before opening the secondary session.

ECC DriverError is silently swallowed

fuzz/​fuzz_targets/​ddi/​tbor/​fuzz_tbor_cmd_reqs.rs:132

This wildcard converts ECC DriverError results into an ordinary request failure. For invalid session IDs or unsupported scopes, the later assertion expects false, so an I/O abort is silently accepted instead of being reported as the crash this fuzz target is meant to detect; the AES branch above and the other TBOR fuzz targets explicitly panic on DriverError. Preserve that arm before the wildcard.

This issue also appears on line 148 of the same file.