Module kdf 

Shared guards for key derivation from untrusted inputs. Guards for Argon2 parameters read from untrusted file headers.

Every code path that derives a key from header-supplied parameters (decryption and listing alike) must validate them here first, so a crafted .shadow file cannot request an enormous allocation or an excessive amount of CPU time.

Constants

KDF_MEMORY_BUDGET_KIB

Total Argon2 buffer memory allowed across all concurrent derivations.

MAX_KDF_ITERATIONS

MAX_KDF_KEY_SIZE

MAX_KDF_MEMORY_KIB

Upper bounds for KDF parameters read from untrusted file headers. These prevent a crafted file from causing OOM or excessive CPU use.

MAX_KDF_PARALLELISM

Functions

derive_untrusted_key

Derives a parsed file’s key from a password, guarding the (untrusted) KDF parameters its header requests.

validate_kdf_request

Validates the KDF parameters a file header requests, against the bounds above. The request is version-agnostic, so every format version passes through the same checks.

with_kdf_memory_permit

Runs f (a key derivation) while holding a reservation of cost_kib against the global memory budget, blocking until enough budget is free.