s3: support s3:x-amz-server-side-encryption policy condition (#8806)

* s3: support s3:x-amz-server-side-encryption policy condition (#7680)

- Normalize x-amz-server-side-encryption header values to canonical form
  (aes256 → AES256, aws:kms mixed-case → aws:kms) so StringEquals
  conditions work regardless of client capitalisation
- Exempt UploadPart and UploadPartCopy from SSE Null conditions: these
  actions inherit SSE from the initial CreateMultipartUpload request and
  do not re-send the header, so Deny/Null("true") should not block them
- Add sse_condition_test.go covering StringEquals, Null, case-insensitive
  normalisation, and multipart continuation action exemption

* s3: address review comments on SSE condition support

- Replace "inherited" sentinel in injectSSEForMultipart with "AES256" so
  that StringEquals/Null conditions evaluate against a meaningful value;
  add TODO noting that KMS multipart uploads need the actual algorithm
  looked up from the upload state
- Rewrite TestSSECaseInsensitiveNormalization to drive normalisation
  through EvaluatePolicyForRequest with a real *http.Request so regressions
  in the production code path are caught; split into AES256 and aws:kms
  variants to cover both normalisation branches

* s3: plumb real inherited SSE from multipart upload state into policy eval

Instead of injecting a static "AES256" sentinel for UploadPart/UploadPartCopy,
look up the actual SSE algorithm from the stored CreateMultipartUpload entry
and pass it through the evaluation chain.

Changes:
- PolicyEvaluationArgs gains InheritedSSEAlgorithm string; set by the
  BucketPolicyEngine wrapper for multipart continuation actions
- injectSSEForMultipart(conditions, inheritedSSE) now accepts the real
  algorithm; empty string means no SSE → Null("true") fires correctly
- IsMultipartContinuationAction exported so the s3api wrapper can use it
- BucketPolicyEngine gets a MultipartSSELookup callback (set by S3ApiServer)
  that fetches the upload entry and reads SeaweedFSSSEKMSKeyID /
  SeaweedFSSSES3Encryption to determine the algorithm
- S3ApiServer.getMultipartSSEAlgorithm implements the lookup via getEntry
- Tests updated: three multipart cases (AES256, aws:kms, no-SSE-must-deny)
  plus UploadPartCopy coverage
This commit is contained in:
Chris Lu
2026-03-27 23:15:01 -07:00
committed by GitHub
parent e3f052cd84
commit 7d5cbfd547
6 changed files with 354 additions and 1 deletions

View File

@@ -0,0 +1,249 @@
package policy_engine
import (
"net/http"
"testing"
)
// requiresSSEPolicy is a bucket policy that denies PutObject when the
// x-amz-server-side-encryption header is absent (Null == true).
const requiresSSEPolicy = `{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "DenyUnencryptedUploads",
"Effect": "Deny",
"Principal": "*",
"Action": "s3:PutObject",
"Resource": "arn:aws:s3:::test-bucket/*",
"Condition": {
"Null": {
"s3:x-amz-server-side-encryption": "true"
}
}
}
]
}`
// requiresAES256Policy denies PutObject unless AES256 is explicitly requested.
const requiresAES256Policy = `{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "AllowAES256Only",
"Effect": "Allow",
"Principal": "*",
"Action": "s3:PutObject",
"Resource": "arn:aws:s3:::test-bucket/*",
"Condition": {
"StringEquals": {
"s3:x-amz-server-side-encryption": "AES256"
}
}
}
]
}`
// requiresKMSPolicy allows PutObject only when aws:kms encryption is requested.
const requiresKMSPolicy = `{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "AllowKMSOnly",
"Effect": "Allow",
"Principal": "*",
"Action": "s3:PutObject",
"Resource": "arn:aws:s3:::test-bucket/*",
"Condition": {
"StringEquals": {
"s3:x-amz-server-side-encryption": "aws:kms"
}
}
}
]
}`
// multipartPolicy denies PutObject when SSE is absent but should NOT block UploadPart.
const multipartPolicy = `{
"Version": "2012-10-17",
"Statement": [
{
"Sid": "DenyUnencryptedUploads",
"Effect": "Deny",
"Principal": "*",
"Action": ["s3:PutObject", "s3:UploadPart", "s3:UploadPartCopy"],
"Resource": "arn:aws:s3:::test-bucket/*",
"Condition": {
"Null": {
"s3:x-amz-server-side-encryption": "true"
}
}
}
]
}`
func newEngineWithPolicy(t *testing.T, policy string) *PolicyEngine {
t.Helper()
engine := NewPolicyEngine()
if err := engine.SetBucketPolicy("test-bucket", policy); err != nil {
t.Fatalf("SetBucketPolicy: %v", err)
}
return engine
}
func evalArgs(action string, conditions map[string][]string) *PolicyEvaluationArgs {
return &PolicyEvaluationArgs{
Action: action,
Resource: "arn:aws:s3:::test-bucket/object.txt",
Principal: "*",
Conditions: conditions,
}
}
func evalArgsWithSSE(action, inheritedSSE string) *PolicyEvaluationArgs {
return &PolicyEvaluationArgs{
Action: action,
Resource: "arn:aws:s3:::test-bucket/object.txt",
Principal: "*",
Conditions: map[string][]string{},
InheritedSSEAlgorithm: inheritedSSE,
}
}
// TestSSEStringEqualsPresent StringEquals with AES256 header present should Allow.
func TestSSEStringEqualsPresent(t *testing.T) {
engine := newEngineWithPolicy(t, requiresAES256Policy)
conditions := map[string][]string{
"s3:x-amz-server-side-encryption": {"AES256"},
}
result := engine.EvaluatePolicy("test-bucket", evalArgs("s3:PutObject", conditions))
if result != PolicyResultAllow {
t.Errorf("expected Allow, got %v", result)
}
}
// TestSSEStringEqualsWrongValue StringEquals with wrong SSE value should not Allow.
func TestSSEStringEqualsWrongValue(t *testing.T) {
engine := newEngineWithPolicy(t, requiresAES256Policy)
conditions := map[string][]string{
"s3:x-amz-server-side-encryption": {"aws:kms"},
}
result := engine.EvaluatePolicy("test-bucket", evalArgs("s3:PutObject", conditions))
if result == PolicyResultAllow {
t.Errorf("expected non-Allow, got %v", result)
}
}
// TestSSENullConditionAbsent Null("true") matches when header is absent → Deny.
func TestSSENullConditionAbsent(t *testing.T) {
engine := newEngineWithPolicy(t, requiresSSEPolicy)
// No SSE header → condition "Null == true" matches → Deny statement fires
result := engine.EvaluatePolicy("test-bucket", evalArgs("s3:PutObject", map[string][]string{}))
if result != PolicyResultDeny {
t.Errorf("expected Deny (no SSE header), got %v", result)
}
}
// TestSSENullConditionPresent Null("true") does NOT match when header is present → not Deny.
func TestSSENullConditionPresent(t *testing.T) {
engine := newEngineWithPolicy(t, requiresSSEPolicy)
conditions := map[string][]string{
"s3:x-amz-server-side-encryption": {"AES256"},
}
result := engine.EvaluatePolicy("test-bucket", evalArgs("s3:PutObject", conditions))
// Deny condition not matched; no explicit Allow → Indeterminate
if result == PolicyResultDeny {
t.Errorf("expected non-Deny when SSE header present, got Deny")
}
}
// TestSSECaseInsensitiveNormalizationAES256 drives the AES256 normalisation
// through EvaluatePolicyForRequest so that a regression in the production
// code path would be caught. The request carries the header in lowercase
// ("aes256"); after normalisation it must match the policy's "AES256" value.
func TestSSECaseInsensitiveNormalizationAES256(t *testing.T) {
engine := newEngineWithPolicy(t, requiresAES256Policy)
req, _ := http.NewRequest(http.MethodPut, "/", nil)
req.RemoteAddr = "1.2.3.4:1234"
req.Header.Set("X-Amz-Server-Side-Encryption", "aes256") // lowercase
result := engine.EvaluatePolicyForRequest("test-bucket", "object.txt", "PutObject", "*", req)
if result != PolicyResultAllow {
t.Errorf("expected Allow after AES256 case normalisation, got %v", result)
}
}
// TestSSECaseInsensitiveNormalizationKMS drives the aws:kms branch of the
// normalisation through the production code path. The request carries
// "AWS:KMS" (mixed case); after normalisation it must match "aws:kms".
func TestSSECaseInsensitiveNormalizationKMS(t *testing.T) {
engine := newEngineWithPolicy(t, requiresKMSPolicy)
req, _ := http.NewRequest(http.MethodPut, "/", nil)
req.RemoteAddr = "1.2.3.4:1234"
req.Header.Set("X-Amz-Server-Side-Encryption", "AWS:KMS") // mixed case
result := engine.EvaluatePolicyForRequest("test-bucket", "object.txt", "PutObject", "*", req)
if result != PolicyResultAllow {
t.Errorf("expected Allow after aws:kms case normalisation, got %v", result)
}
}
// TestSSEMultipartAES256Exempt UploadPart with AES256 inherited from
// CreateMultipartUpload is not blocked by the Null("true") deny condition.
func TestSSEMultipartAES256Exempt(t *testing.T) {
engine := newEngineWithPolicy(t, multipartPolicy)
result := engine.EvaluatePolicy("test-bucket", evalArgsWithSSE("s3:UploadPart", "AES256"))
if result == PolicyResultDeny {
t.Errorf("UploadPart with inherited AES256 should not be Deny, got Deny")
}
}
// TestSSEMultipartKMSExempt UploadPart with aws:kms inherited from
// CreateMultipartUpload is not blocked by the Null("true") deny condition.
func TestSSEMultipartKMSExempt(t *testing.T) {
engine := newEngineWithPolicy(t, multipartPolicy)
result := engine.EvaluatePolicy("test-bucket", evalArgsWithSSE("s3:UploadPart", "aws:kms"))
if result == PolicyResultDeny {
t.Errorf("UploadPart with inherited aws:kms should not be Deny, got Deny")
}
}
// TestSSEMultipartNoSSEDenied UploadPart for an upload that had no SSE
// must still be denied by the Null("true") deny condition.
func TestSSEMultipartNoSSEDenied(t *testing.T) {
engine := newEngineWithPolicy(t, multipartPolicy)
// inheritedSSE="" means CreateMultipartUpload was sent without SSE
result := engine.EvaluatePolicy("test-bucket", evalArgsWithSSE("s3:UploadPart", ""))
if result != PolicyResultDeny {
t.Errorf("UploadPart with no inherited SSE should be Deny, got %v", result)
}
}
// TestSSEUploadPartCopyKMSExempt UploadPartCopy with aws:kms is also exempt.
func TestSSEUploadPartCopyKMSExempt(t *testing.T) {
engine := newEngineWithPolicy(t, multipartPolicy)
result := engine.EvaluatePolicy("test-bucket", evalArgsWithSSE("s3:UploadPartCopy", "aws:kms"))
if result == PolicyResultDeny {
t.Errorf("UploadPartCopy with inherited aws:kms should not be Deny, got Deny")
}
}
// TestSSEPutObjectStillBlockedWithoutHeader regular PutObject still denied without SSE.
func TestSSEPutObjectStillBlockedWithoutHeader(t *testing.T) {
engine := newEngineWithPolicy(t, multipartPolicy)
result := engine.EvaluatePolicy("test-bucket", evalArgs("s3:PutObject", map[string][]string{}))
if result != PolicyResultDeny {
t.Errorf("PutObject without SSE should be Deny, got %v", result)
}
}