Commit Graph
4 Commits
Author SHA1 Message Date
Chris LuandDevin c0152e6be1 s3: keep '\' a literal object-key character behind -s3.allowBackslashInKey (#11911)
* s3: keep '\' a literal object-key character when AllowBackslashInKey is set

NormalizeObjectKey rewrites every S3 object key: '\' becomes '/' and
duplicate slashes collapse. On AWS S3 both are ordinary key characters,
so keys that are distinct there alias one object here — writing
probe/back/slash.txt silently overwrites probe/back\slash.txt.

The filer only treats '/' as a path separator, so a verbatim '\' stays
inside one entry name. Gate the backslash rewrite and the matching '\'
handling in IsValidObjectKey behind a process-wide mode the S3 server
sets from the new S3ApiServerOption. Duplicate-slash collapsing stays:
an entry name cannot contain an empty segment.

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* command: add -s3.allowBackslashInKey flag for AWS-compatible key handling

Registers the flag on all four S3 entry points (s3, server -s3,
filer -s3, mini) and passes it through S3Options into
S3ApiServerOption. Default off, so existing normalization is
unchanged.

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* s3: correct IsValidObjectKey/NormalizeObjectKey docs under allowBackslashInKey

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* s3: normalize DeleteObjects body keys the same as path keys

DeleteObjects keys arrive in the XML body, so they bypassed the
normalization applied to route-var keys. The lock, the authorization
checks, the table-bucket layout check and the filer delete itself all
addressed the raw key while the conditional check resolved the
normalized one, so a key spelled with '\' or '//' could be reported
deleted while the stored entry survived. Echo the client-sent key in
the result while operating on the normalized form.

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* s3: report a normalized-empty DeleteObjects key as a delete no-op

A multi-delete key of only slashes normalizes to the empty string. Left
to reach the filer delete, the empty name resolves to the bucket entry
itself, so an unauthorized caller could remove a bucket through the
body-key path. Such a key can never name a stored entry, so like a
missing key the delete is an idempotent no-op reported before any
permission check or filer call.

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* s3: drop unused AllowBackslashInObjectKey getter

* s3: answer conditional delete of a normalized-empty key with NoSuchKey

* s3: normalize the probed key in authorizeAnonymousBucketList

The masked-miss probe read the raw mux var, so a spelling like folder//
or folder\ was authorized against a key that can never exist while the
request itself targets the normalized folder/. Probe the normalized key
so the answer matches what the read path authorizes.

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* s3: cover anonymous authz of a literal-backslash key under allowBackslashInKey

A public grant on the slash key must not authorize an anonymous read of
the distinct backslash object when the flag keeps '\' literal; grant the
backslash key's own ACL and it reads back. Default mode still folds the
spelling onto the covered slash key.

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* s3: publish the key mode only after the S3 server is constructed

A failed NewS3ApiServerWithStore could previously flip the process-wide
key mode out from under an already-running gateway.

* s3: normalize the copy-source key before validation and authorization

pathToBucketObjectAndVersion returned the raw header spelling, so an
equivalent spelling (a//b, a\b) was authorized and compared against the
normalized destination while resolveCopySourceEntry looked up the
normalized key — a deny on the canonical key could be bypassed and
self-copy detection missed. Normalize once at parse so the CopyObject and
UploadPartCopy paths agree.

---------

Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
2026-10-21 20:02:04 -07:00
Javier de la TorreandJavier de la Torre f40267db44 s3: answer InvalidBucketName to a denied request on a malformed bucket name (#11893)
* s3: answer InvalidBucketName to a denied request on a malformed bucket name

The store authorizes a request before it looks at the bucket, so a caller
denied on a bucket whose name breaks the S3 naming rules (upper case, an
underscore, too short, two adjacent periods, a non-ASCII letter) gets 403
AccessDenied, where AWS S3 answers 400 InvalidBucketName. Clients and
compatibility suites that check the error code read the 403 as a permission
problem.

Auth and AuthPostPolicy now turn an AccessDenied for a resolved identity into
InvalidBucketName when the bucket name fails VerifyS3BucketName or uses a
character outside a-z, 0-9, '.' and '-' (VerifyS3BucketName checks with
unicode.IsLower/IsNumber, which accept letters such as 'ü'). The answer depends
on the name alone, so it reveals nothing about which buckets exist. An
authentication failure, an allowed request and a denial on a well-formed name
answer as before.

Test: TestAuthDeniedInvalidBucketName drives iam.Auth with signed and anonymous
requests; on master every malformed name answers 403, with the change 400,
while the identity's own bucket stays allowed and a well-formed foreign name
stays 403. TestRefineDenialForBucketName covers the rule table.

* s3: refine POST-policy and deferred anonymous-read denials on a malformed bucket name

Two denial paths bypass the refinement in Auth and AuthPostPolicy:

- A browser POST upload carries its credentials in the form, so
  AuthPostPolicy delegates it to PostPolicyBucketHandler, which verifies the
  form and writes AccessDenied itself when the signer may not write the bucket
  or the per-key authorization denies the object. Both denials now go through
  refineDenialForBucketName with the verified identity.

  The coarse Write check used to run inside doesPolicySignatureV2Match and
  doesPolicySignatureV4Match before the signature was compared, so a form with
  a wrong signature was told whether the key may write the bucket. It now runs
  in doesPolicySignatureMatch after the signature verifies, as on the
  header-signed path; a form that fails verification answers
  SignatureDoesNotMatch (or MissingFields) and is never refined.

- Unsigned GET/HEAD object reads are deferred by AuthWithPublicRead to the
  object handlers, where writeAnonymousAwareNotFound masks a miss as
  AccessDenied. That denial is refined with the anonymous identity, so a
  missing malformed bucket answers InvalidBucketName when an anonymous
  identity is configured, as Auth does. A denial on an entry that was found
  is left alone: the bucket exists.

Test: TestPostPolicyDeniedInvalidBucketName drives AuthPostPolicy with signed
forms (Write denied, per-key policy deny, bad signature, well-formed name);
TestAnonymousReadDeniedInvalidBucketName drives AuthWithPublicRead with GET and
HEAD, with and without an anonymous identity. Both fail before this change.

* s3: refine a denied anonymous read of an existing key on a malformed bucket name

A deferred anonymous GET/HEAD refined only its masked miss to
InvalidBucketName, so in a bucket whose name breaks the S3 rules (one
VerifyS3BucketName still accepts, such as a non-ASCII name) a missing key
answered 400 and an existing private key 403, telling the caller which
keys exist. The entry check now refines its denial the same way, so both
answer alike. Without an anonymous identity no identity resolves and both
stay 403, as in Auth.

The deny-precedence case in TestAnonymousObjectACLConfiguredIdentity runs
on the fixture bucket "b", shorter than S3's three-character minimum, so
its denial now answers InvalidBucketName.

---------

Co-authored-by: Javier de la Torre <jatorre@lakehousebox.com>
2026-10-21 14:08:33 -07:00
Chris LuandDevin 0de6347b11 s3: mask anonymous misses behind AccessDenied unless the bucket is listable (#11857)
* s3: mask anonymous misses behind AccessDenied unless the bucket is listable

Deferred anonymous GET/HEAD authorization only runs once an entry is
selected, so misses returned 404 while existing keys returned 403 — an
unauthenticated existence oracle for bucket names and object keys.

Route not-found responses in Get/HeadObjectHandler through a check that
only discloses 404 when anonymous listing is allowed (policy, identity or
a public-read bucket); otherwise the miss is indistinguishable from a
denied read, matching AWS and 4.48 behavior.

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* s3: mask missing-directory misses for anonymous reads too

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* s3: check a fixed request shape when masking anonymous misses

The miss check passed the caller's request through, so query parameters
could retarget the resolved action (?policy) or satisfy an s3:prefix
condition on an unrelated subtree. Each check now runs on a request with a
fixed shape: a ListBucket scoped to the probed key and a plain read of the
key, so the miss only shows when the caller could learn the same fact
directly.

* s3: mask conditional-header misses for anonymous reads

An If-Match conditional on a missing key wrote NoSuchKey directly from
processConditionalHeaders, before the handlers reached the masked miss
path, so anonymous callers could still distinguish a missing key from a
denied read.

* s3: keep the versionId when masking anonymous misses

The read leg must evaluate the action the caller's request resolves to:
a versioned miss is s3:GetObjectVersion, and dropping versionId would let a
plain GetObject grant disclose versions the caller may not read.

---------

Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
2026-10-20 12:52:58 -07:00
aa5b337716 fix(s3): honor object ACLs for anonymous GET and HEAD (#11605)
* fix(s3): honor object ACLs for anonymous reads

Signed-off-by: zhaoyuchen <43179751+zhao-yc@users.noreply.github.com>

* s3: drop unsigned session tokens on deferred anonymous reads

An unsigned GET/HEAD carrying X-Amz-Security-Token is anonymous, not a
session request; strip the token before authentication and authorization
so it cannot influence identity or policy evaluation.

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Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

---------

Signed-off-by: zhaoyuchen <43179751+zhao-yc@users.noreply.github.com>
Co-authored-by: Chris Lu <chrislusf@users.noreply.github.com>
Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
2026-10-06 09:52:37 +08:00