* feat(kms): add AppRole configuration surface for Vault auth
Extend VaultAuthMethod::AppRole with secret_id_file (re-read on every
login so external rotation is picked up), a configurable auth mount
(default "approle"), and an optional fail-closed safety window. All new
fields are serde(default) so previously persisted configurations keep
deserializing, and the strict admin-configure deserializer accepts them
as optional.
Environment selection: setting RUSTFS_KMS_VAULT_APPROLE_ROLE_ID switches
both Vault backends to AppRole; the secret_id comes from
RUSTFS_KMS_VAULT_APPROLE_SECRET_ID_FILE (path stored, file wins) or
RUSTFS_KMS_VAULT_APPROLE_SECRET_ID, following the static secret-key file
precedent. validate() rejects AppRole configs without a role_id, without
any secret_id source, or with an empty mount.
Also append the CredentialsUnavailable error variant used by the
fail-closed credential gate.
* feat(kms): implement AppRole login with background renewal and fail-closed expiry
Implement the AppRoleLogin token source (vaultrs approle login +
renew-self) and wire lease-bound credentials through the provider:
- Each successful login/renewal installs a new client generation in the
ArcSwap; in-flight requests finish on the generation they captured.
- A background renewal task refreshes at half the lease TTL: renewable
tokens are renewed in place, everything else (or a failed renewal)
falls back to a fresh login. Auth exchanges run under the typed retry
policy (OpClass::Auth) and failed cycles retry on a fixed cadence, so
the provider recovers once Vault does.
- Fail-closed: current() refuses to hand out a token inside the
configured safety window of its expiry (default: one attempt timeout),
returning CredentialsUnavailable instead of sending a request whose
token may lapse mid-flight.
- Refreshes are single-flight: concurrent triggers for the same
generation coalesce into one login.
- The renewal task's owner handle lives on the KMS service version:
stop() shuts it down explicitly and reconfigure recycles it via
cancel-on-drop when the old version is discarded.
- The secret_id file is re-read on every login attempt; missing or empty
files fail the attempt without contacting Vault. Crate-owned copies of
tokens and secret_ids are zeroized on drop, and Debug output of every
credential-carrying type stays redacted (leak regression tests).
The renewal machinery is covered by paused-clock tests driving a
scripted token source: renew-at-half-TTL timing, login fallback,
fail-closed window entry and recovery, prompt task recycling, and
coalesced concurrent refreshes.
* feat(kms): add Vault Agent token file authentication
Add the TokenFile source: the token is read from an agent-managed sink
file (RUSTFS_KMS_VAULT_TOKEN_FILE or the TokenFile auth config) and
re-read once per poll interval (default 30s) through the existing
renewal loop, so a token rotated by the agent installs a new client
generation within one poll of the atomic replace. Each successful read
extends the token's observed validity to twice the poll interval; a
file that disappears or turns empty keeps failing the refresh until the
fail-closed window trips, and heals the provider as soon as it is
restored.
Reads are strict and never contact Vault on failure: the file must be
non-empty after trimming, and on Unix group/other permission bits are a
hard error (mirroring the SFTP host-key rule). Rotation detection uses
a content digest; the token itself is never stored on the source and
the crate-owned copy is zeroized.
Configuring the token file together with AppRole or an explicit static
token is rejected as a configuration error. All new config fields are
serde(default) and the strict admin-configure deserializer accepts the
new variant.
Covered by paused-clock tests (atomic replacement installs a new
generation next cycle, deletion fails closed and recovers, prompt task
recycling) plus negatives for missing/empty/over-permissive files and a
Debug leak regression.
* docs(kms): add Vault authentication and credential lifecycle runbook
Cover choosing between static token, AppRole, and Vault Agent token
file auth; AppRole role setup with SecretID delivery and rotation;
Agent sink deployment with the permission requirements; and the
fail-closed window semantics with a troubleshooting table keyed on the
renewal task's log lines.
* feat(kms): retain historical master key versions for Vault KV2 rotation
Rotation previously had to be rejected outright because replacing the
stored material would orphan every DEK wrapped by earlier versions.
Vault KV2 now keeps each version's material in an immutable, create-only
record at {prefix}/{key_id}/versions/{N} and treats the top-level record
as the current-version pointer plus fast-path material copy:
- decrypt resolves the envelope's master_key_version to its version
record; a missing version fails closed with KeyVersionNotFound and
never falls back to the current material
- envelopes without a version (pre-versioning writers) resolve to the
baseline_version frozen at the key's first rotation, so never-rotated
keys behave exactly as before
- generate_data_key stamps the wrapping version from the same key record
snapshot that supplied the material
- rotate_key commits in check-and-set order: freeze baseline, persist
the next version's material, then switch the current pointer; any
failure leaves the current pointer untouched, and concurrent rotations
serialize on the CAS writes with monotonically unique versions
- key listings drop the versions/ directory entries and physical key
deletion purges version records before the key record
Refs rustfs/backlog#1565
* test(kms): pin rotation contracts across backends and document retention
Completes the backlog#1565 series with the cross-backend regression net
and operator documentation:
- Vault Transit: ignored integration test proving version-prefixed
historical ciphertext still decrypts after rotation, with no
RustFS-side version bookkeeping in the envelope
- Local: offline mixed-format test interleaving pre-versioning and
versioned envelopes through a rejected rotation; the existing
rotation-rejection pinning test already covers material immutability
- docs: kms-backend-security.md gains the KV2 versioned retention
model, version record retention/destruction preconditions, and the
upgrade-before-first-rotation cluster constraint
Refs rustfs/backlog#1565
Zhengchao An