The address MinIO attributes a request to is read from X-Forwarded-For,
X-Real-IP or RFC 7239 Forwarded, and never from the connection unless all
three are absent. It becomes aws:SourceIp and the audit remotehost field,
so any client that can reach the API port chooses the value an IpAddress
condition is evaluated against and the address every logged action is
attributed to.
MINIO_API_TRUSTED_PROXIES now selects who may make that claim:
unset the historical behaviour, unchanged
none no forwarded header is believed; the TCP peer wins
<CIDRs> believed only from listed peers, chains read right-to-left
Reading right-to-left is what makes an appending proxy safe: each hop
appends the peer it actually saw, so an entry a client injected can only
sit to the left of one a proxy wrote. The stock nginx recipe
$proxy_add_x_forwarded_for appends, which leaves the client's entry
left-most - exactly where the untrusted path reads - so a deployment with
no direct route to the API port was forgeable too.
_MINIO_API_XFF_HEADER is deliberately untouched, in semantics and in read
timing. Widening it to mean "trust nothing" was implemented and reverted:
it is the only part of this change that could alter a deployed
configuration, and the new variable expresses the same guarantee at no
compatibility cost. Upstream's TestXFFDisabled is retained verbatim.
Notes on the allow-list mode, all covered by tests:
- it must name proxies, not the subnet they sit in; listed entries are
skipped while walking, so a range covering clients lets them forge
- a cluster must list its own nodes, because MinIO forwards between
them and a client can force a hop via the ListObjectsV2 token
- loopback is trusted as a peer, not as a chain entry, so FTP and SFTP
keep attributing their sessions
- the node-to-node forwarder drops X-Real-IP and Forwarded from a peer
not entitled to have set them
- the walk scans the header in place and stops after 100 hops, so a
long chain costs neither allocation nor unbounded work
No behaviour change for any deployment that does not set the new
variable: the untrusted path is a verbatim copy of the previous function
body, differentially verified against it over ~5.1M header combinations.
The LDAP STS allow-list now shares the list parser as pure code motion,
verified identical across every combination of 37 allow-list values and
21 peer addresses.
Co-authored-by: ChatGPT <noreply@openai.com>
Co-authored-by: Claude <noreply@anthropic.com>
A bucket policy that allows s3:DeleteObject only when s3:versionid is null
-- Condition {"Null": {"s3:versionid": "true"}}, the idiom for "let clients
delete current objects but not roll back versions" -- denied every delete,
including the version-less ones it was meant to permit (upstream issue
minio/minio#21735).
getConditionValues wrote "versionid": {""} unconditionally. The condition
engine decides Null by slice length (nullfunc.evaluate), so a present-but-
empty value reads as "key present": Null:true never matched and Null:false
always did. Absent and empty were indistinguishable.
Writing the key only when the request names a version fixes the reported
case but, alone, opens a worse one. DeleteObjects carries each object's
version in the XML body, which getConditionValues -- reading only r.Form --
never sees. A body version would then vanish from the map, read as null,
and a policy meant to protect old versions would authorize deleting a
specific one. So authorization also rebinds versionid to the effective,
server-resolved reqInfo.VersionID for DeleteObjectAction: the per-entry
body value that checkRequestAuthTypeWithVID already sets in the
DeleteObjects loop, deleting the key when that value is empty. A
query-level ?versionId on a DeleteObjects POST no longer leaks into any
entry's decision.
Finally, trim the version the condition builder reads. newContext and
getOpts both TrimSpace it before the object layer acts, so an untrimmed
value here let a padded ?versionId=V%20 present a different s3:versionid
than the version actually operated on, sidestepping a Deny keyed on
StringEquals s3:versionid. DeleteObjectAction was already immune via the
trimmed reqInfo value; this covers GetObject, tagging, retention, and the
copy-source read.
Tests: an end-to-end DeleteObjects against a Null:{s3:versionid:true}
policy over versioned objects (with a decoy query versionId proving the
per-entry body value wins), and a unit test asserting key presence,
trimming, and the copy-source fallback.
Co-authored-by: ChatGPT <noreply@openai.com>
Co-authored-by: Claude <noreply@anthropic.com>
Policy evaluation mixed server-derived identity and transport values with raw headers and query parameters. A client could therefore shadow internal condition keys, synthesize LDAP or JWT resource variables, substitute request tags for stored tags, or make a condition observe a value different from the one the handler actually used.
Partition condition sources, reserve internal names, adopt exact-name lookup from silo-pkg, and bind authorization to the effective request state. Preserve compatible query forms for storage class and upload tags with explicit header precedence, while restricting signature age and existing-object tags to authenticated or server-resolved values.
Tests sweep every supported key across header and query routes and exercise LDAP/OIDC variables, object-lock spelling, STS tags, metadata extraction, and end-to-end policy decisions.
Co-authored-by: ChatGPT <noreply@openai.com>
Co-authored-by: Claude <noreply@anthropic.com>
Feng Ruohang