Bucket policy `Principal` named callers by access key id. Under the standalone IAM service it now names them by AWS-style ARN, as real S3 does: a user ARN, a role ARN (covering every session of that role), an assumed-role ARN (covering one session), the account root ARN or bare account id, or `*`. Every other IAM backend has no ARNs to name anything by and keeps access-key principals unchanged, gated on a new `auth.PrincipalResolver` capability interface that only the standalone client implements.
`auth.Account` carries `Arn` and `RoleArn`, filled at authentication time, so a session can be matched against both its own ARN and its role's. Principals are validated at PutBucketPolicy time through a new `/private/resolve-principals` endpoint, which rejects anything that does not name a live identity with `MalformedPolicy: Invalid principal in policy`.
An `Allow` naming the account root ARN or bare account id delegates to the account's own IAM rather than granting on its own, while a `Deny` naming it denies every principal in the account outright. Denial messages now name the caller by ARN wherever one exists.
Also fixes `aws:PrincipalArn` for assumed-role sessions, which reported the session ARN where AWS reports the role's, and stops an unreachable IAM service being reported as a malformed policy.
Fixes#1327Fixes#1567Closes#2264
Wires the S3 gateway up to the standalone IAM service so identity policies, not just bucket policies and ACLs, are enforced on the S3 data plane. The gateway authenticates SigV4 requests by calling new private derive-signing-key and resolve-identity endpoints on the IAM service instead of holding secrets itself, and evaluates identity policy through the same PolicyEvaluator path added to auth.VerifyAccess, combined with the bucket policy using explicit-deny-wins precedence. The private endpoints are served over their own mTLS listener (new iamapi/private package, genmtlscerts.sh to generate test material, and client-cert support in internal/netutil), separate from the public IAM API. As part of this the vendored aws/signer/v4 package is deleted and replaced by a pure-Go SigV4 implementation in internal/sigv4auth, which now reads canonical request data directly off the fiber.Ctx instead of reconstructing an http.Request, and is shared by both the S3 request-signing verification and the new private-endpoint signing.
DeleteObjects moves from an all-or-nothing authorization check to true partial success: VerifyObjectsAccess evaluates every object in a batch independently against both the identity policy and any object lock, so a denial or a locked object only removes that key from the batch instead of failing the whole request. It also batches the identity-policy round trip and the bucket-policy fetch once per request rather than once per object, and separates plain deletes from versioned ones since a versioned delete needs s3:DeleteObjectVersion rather than s3:DeleteObject. Object lock handling got a few correctness fixes alongside this: a bypass is now modeled as BypassNone/BypassRequested/BypassOverwrite rather than a single bool, because root's blanket ability to override a GOVERNANCE retention should only apply when the client actually asked to bypass it (DeleteObject/DeleteObjects/PutObjectRetention), not when the gateway is silently replacing a locked object via an overwrite, which needs the permission from everyone including root. Retention changes are now correctly classified as an extension (allowed under plain s3:PutObjectRetention) versus a weakening (date or mode change, which needs the bypass permission), and a COMPLIANCE lock can never be weakened by anyone regardless of permissions, matching AWS. Separately, VerifyObjectCopyAccess had a readonly-mode gap: it returned early for root/admin before ever calling VerifyAccess, so the readonly check inside VerifyAccess never ran for them on CopyObject; access checks are now ordered so the readonly gate always applies before any root/admin bypass, for copy as well as every other write path.
Bucket policies also gained Condition block support, via a new shared internal/condition package moved out of the IAM policy package since both bucket and identity policies share the same evaluation semantics. It implements the full AWS operator set — String{Equals,NotEquals,EqualsIgnoreCase,NotEqualsIgnoreCase,Like,NotLike}, Numeric{Equals,NotEquals,LessThan,LessThanEquals,GreaterThan,GreaterThanEquals}, Date{Equals,NotEquals,LessThan,LessThanEquals,GreaterThan,GreaterThanEquals}, Bool, BinaryEquals, Arn{Equals,Like,NotEquals,NotLike}, IpAddress/NotIpAddress, and Null — along with the ForAllValues/ForAnyValue set qualifiers and the IfExists modifier. A new requestConditionContext builds the per-request keys a bucket policy's Condition block can reference — aws:SourceIp, aws:SecureTransport, aws:CurrentTime, aws:EpochTime, aws:UserAgent, aws:Referer, s3:prefix, s3:delimiter, s3:max-keys, s3:x-amz-acl, s3:VersionId — following AWS's own per-action rules for which keys a given S3 operation actually populates. Identity-derived keys such as aws:PrincipalArn and aws:username are deliberately left unwired here, since the gateway has no way to know them; the standalone IAM service fills those in itself when it evaluates an identity policy.
Also added new integration test suites for S3-side IAM: s3_iam_access_control.go and s3_iam_session_access_control.go cover identity-policy enforcement and session-credential requests against real S3 operations, alongside expanded OIDC/web-identity coverage and a new runoidctests.sh runner wired into the OIDC GitHub Actions workflow.
Object key validation allowed internal parent-directory segments such as `public/../private.txt`. Bucket policy and auth checks evaluated the raw key, so a policy allowing bucket/public/* could match the request while posix backend later resolved the key with `filepath.Join` and accessed `bucket/private.txt`.
Add backend-specific object key normalization to close that mismatch. The Backend interface now exposes `NormalizeObjectKey` so authorization can evaluate resources using the same key shape a backend will use for storage access.
Backends that do not collapse object paths, including Azure and the S3 proxy, inherit `BackendUnsupported.NormalizeObjectKey`. That implementation returns the input key unchanged, avoiding unnecessary normalization and keeping policy evaluation unpolluted for object stores where ../ is part of the key name.
posix/scoutfs normalize keys with filepath.Join so policy resources and request keys are compared after internal dot segments are collapsed.
Bucket policy evaluation now normalizes both the incoming object key and object resource patterns from the policy before matching. Object lock governance bypass policy checks use the same backend normalizer as well, so retention and legal hold authorization cannot diverge from backend path resolution.
Distinguish public bucket policy no-match from explicit deny during anonymous access checks. This preserves ACL fallback only for requests that are not allowed by policy, while ensuring a matching Deny statement short-circuits authorization and returns AccessDenied even when a public ACL would otherwise grant access.
Fixes#1986
When a client includes tagging, legal hold, or retention headers in a PutObject, CopyObject or CreateMultipartUpload request, the corresponding bucket policy permissions must be verified in addition to s3:PutObject:
`X-Amz-Tagging` - `s3:PutObjectTagging`
`X-Amz-Object-Lock-Legal-Hold` - `s3:PutObjectLegalHold`
`X-Amz-Object-Lock-Mode` - `s3:PutObjectRetention`
Previously, only s3:PutObject was checked, allowing users to set tagging, legal hold, and retention without having the required permissions. Now each action permission is check, if user tries to add them.
For CopyObject these permissions are checked on destination object.
Closes#1536
Adds bucket policy version support. Two versions are supported: **2008-10-17** and **2012-10-17**. If the `Version` field is omitted in the bucket policy document, it defaults to **2008-10-17**. However, if an empty string (`""`) is provided, it is considered invalid.
Fixes#1488
Adds full wildcard (`*`) and single-character (`?`) support for bucket policy actions, fixes resource detection with wildcards, and includes unit tests for `bucket_policy_actions`, `bucket_policy_effect`, and `bucket_policy_principals`.
Closes#1454
Adds the implementation of [S3 GetBucketPolicyStatus action](https://docs.aws.amazon.com/AmazonS3/latest/API/API_GetBucketPolicyStatus.html). The implementation goes to front-end. Front-End loads the bucket policy and checks if it grants public access to all users.
A bucket policy document `is public` only when `Principal` contains `*`(all users): only when it grants access to `ALL` users.
This implementation introduces **public buckets**, which are accessible without signature-based authentication.
There are two ways to grant public access to a bucket:
* **Bucket ACLs**
* **Bucket Policies**
Only `Get` and `List` operations are permitted on public buckets. All **write operations** require authentication, regardless of whether public access is granted through an ACL or a policy.
The implementation includes an `AuthorizePublicBucketAccess` middleware, which checks if public access has been granted to the bucket. If so, authentication middlewares are skipped. For unauthenticated requests, appropriate errors are returned based on the specific S3 action.
---
**1. Bucket-Level Operations:**
```json
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Principal": "*",
"Action": "s3:*",
"Resource": "arn:aws:s3:::test"
}
]
}
```
**2. Object-Level Operations:**
```json
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Principal": "*",
"Action": "s3:*",
"Resource": "arn:aws:s3:::test/*"
}
]
}
```
**3. Both Bucket and Object-Level Operations:**
```json
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Principal": "*",
"Action": "s3:*",
"Resource": "arn:aws:s3:::test"
},
{
"Effect": "Allow",
"Principal": "*",
"Action": "s3:*",
"Resource": "arn:aws:s3:::test/*"
}
]
}
```
---
```sh
aws s3api create-bucket --bucket test --object-ownership BucketOwnerPreferred
aws s3api put-bucket-acl --bucket test --acl public-read
```
If `Statement` field is missing in the json document in `PutBucketPolicy` body, the gateway returns `Missing required field Statement` error description alongside with `MalformedPolicy` error code.
Fixes#965
Changes the returned error description to `Policies must be valid JSON and the first byte must be '{'` for invalid bucket policy json documents, which doesn't start with `{`.
The gateway returns `This policy contains invalid Json` error description, if the document starts with `{`, but still isn't valid json.
Implements the `policyErr` string type which implements the `error` interface, to handle the policy json document validation errors, by avoiding staticchecker warnings.
Bucket ACLs are now disabled by default the same as AWS.
By default the object ownership is BucketOwnerEnforced
which means that bucket ACLs are disabled. If one attempts
to set bucket ACL the following error is returned both in
the gateway and on AWS:
ErrAclNotSupported: {
Code: "AccessControlListNotSupported",
Description: "The bucket does not allow ACLs",
HTTPStatusCode: http.StatusBadRequest,
},
ACls can be enabled with PutBucketOwnershipControls
Changed bucket canned ACL translation
New backend interface methods:
PutBucketOwnershipControls
GetBucketOwnershipControls
DeleteBucketOwnershipControls
Added these to metrics
Added support to enable object lock on bucket creation in posix and azure
backends.
Implemented the logic to add object legal hold and retention on object creation
in azure and posix backends.
Added the functionality for HeadObject to return object lock related headers.
Added integration tests for these features.
niksis02
Ben McClelland
jonaustin09andBen McClelland