minio/cmd/auth-handler.go
Aditya Manthramurthy 890f43ffa5
Map policy to parent for STS (#13884)
When STS credentials are created for a user, a unique (hopefully stable) parent
user value exists for the credential, which corresponds to the user for whom the
credentials are created. The access policy is mapped to this parent-user and is
persisted. This helps ensure that all STS credentials of a user have the same
policy assignment at all times.

Before this change, for an OIDC STS credential, when the policy claim changes in
the provider (when not using RoleARNs), the change would not take effect on
existing credentials, but only on new ones.

To support existing STS credentials without parent-user policy mappings, we
lookup the policy in the policy claim value. This behavior should be deprecated
when such support is no longer required, as it can still lead to stale
policy mappings.

Additionally this change also simplifies the implementation for all non-RoleARN
STS credentials. Specifically, for AssumeRole (internal IDP) STS credentials,
policies are picked up from the parent user's policies; for
AssumeRoleWithCertificate STS credentials, policies are picked up from the
parent user mapping created when the STS credential is generated.
AssumeRoleWithLDAP already picks up policies mapped to the virtual parent user.
2021-12-17 00:46:30 -08:00

635 lines
21 KiB
Go

// Copyright (c) 2015-2021 MinIO, Inc.
//
// This file is part of MinIO Object Storage stack
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package cmd
import (
"bytes"
"context"
"crypto/subtle"
"encoding/base64"
"encoding/hex"
"errors"
"io"
"io/ioutil"
"net/http"
"net/url"
"strconv"
"strings"
"sync/atomic"
"time"
"github.com/minio/minio/internal/auth"
objectlock "github.com/minio/minio/internal/bucket/object/lock"
"github.com/minio/minio/internal/etag"
"github.com/minio/minio/internal/hash"
xhttp "github.com/minio/minio/internal/http"
xjwt "github.com/minio/minio/internal/jwt"
"github.com/minio/minio/internal/logger"
"github.com/minio/pkg/bucket/policy"
iampolicy "github.com/minio/pkg/iam/policy"
)
// Verify if request has JWT.
func isRequestJWT(r *http.Request) bool {
return strings.HasPrefix(r.Header.Get(xhttp.Authorization), jwtAlgorithm)
}
// Verify if request has AWS Signature Version '4'.
func isRequestSignatureV4(r *http.Request) bool {
return strings.HasPrefix(r.Header.Get(xhttp.Authorization), signV4Algorithm)
}
// Verify if request has AWS Signature Version '2'.
func isRequestSignatureV2(r *http.Request) bool {
return (!strings.HasPrefix(r.Header.Get(xhttp.Authorization), signV4Algorithm) &&
strings.HasPrefix(r.Header.Get(xhttp.Authorization), signV2Algorithm))
}
// Verify if request has AWS PreSign Version '4'.
func isRequestPresignedSignatureV4(r *http.Request) bool {
_, ok := r.Form[xhttp.AmzCredential]
return ok
}
// Verify request has AWS PreSign Version '2'.
func isRequestPresignedSignatureV2(r *http.Request) bool {
_, ok := r.Form[xhttp.AmzAccessKeyID]
return ok
}
// Verify if request has AWS Post policy Signature Version '4'.
func isRequestPostPolicySignatureV4(r *http.Request) bool {
return strings.Contains(r.Header.Get(xhttp.ContentType), "multipart/form-data") &&
r.Method == http.MethodPost
}
// Verify if the request has AWS Streaming Signature Version '4'. This is only valid for 'PUT' operation.
func isRequestSignStreamingV4(r *http.Request) bool {
return r.Header.Get(xhttp.AmzContentSha256) == streamingContentSHA256 &&
r.Method == http.MethodPut
}
// Authorization type.
type authType int
// List of all supported auth types.
const (
authTypeUnknown authType = iota
authTypeAnonymous
authTypePresigned
authTypePresignedV2
authTypePostPolicy
authTypeStreamingSigned
authTypeSigned
authTypeSignedV2
authTypeJWT
authTypeSTS
)
// Get request authentication type.
func getRequestAuthType(r *http.Request) authType {
if r.URL != nil {
var err error
r.Form, err = url.ParseQuery(r.URL.RawQuery)
if err != nil {
logger.LogIf(r.Context(), err)
return authTypeUnknown
}
}
if isRequestSignatureV2(r) {
return authTypeSignedV2
} else if isRequestPresignedSignatureV2(r) {
return authTypePresignedV2
} else if isRequestSignStreamingV4(r) {
return authTypeStreamingSigned
} else if isRequestSignatureV4(r) {
return authTypeSigned
} else if isRequestPresignedSignatureV4(r) {
return authTypePresigned
} else if isRequestJWT(r) {
return authTypeJWT
} else if isRequestPostPolicySignatureV4(r) {
return authTypePostPolicy
} else if _, ok := r.Form[xhttp.Action]; ok {
return authTypeSTS
} else if _, ok := r.Header[xhttp.Authorization]; !ok {
return authTypeAnonymous
}
return authTypeUnknown
}
func validateAdminSignature(ctx context.Context, r *http.Request, region string) (auth.Credentials, map[string]interface{}, bool, APIErrorCode) {
var cred auth.Credentials
var owner bool
s3Err := ErrAccessDenied
if _, ok := r.Header[xhttp.AmzContentSha256]; ok &&
getRequestAuthType(r) == authTypeSigned {
// We only support admin credentials to access admin APIs.
cred, owner, s3Err = getReqAccessKeyV4(r, region, serviceS3)
if s3Err != ErrNone {
return cred, nil, owner, s3Err
}
// we only support V4 (no presign) with auth body
s3Err = isReqAuthenticated(ctx, r, region, serviceS3)
}
if s3Err != ErrNone {
reqInfo := (&logger.ReqInfo{}).AppendTags("requestHeaders", dumpRequest(r))
ctx := logger.SetReqInfo(ctx, reqInfo)
logger.LogIf(ctx, errors.New(getAPIError(s3Err).Description), logger.Application)
return cred, nil, owner, s3Err
}
return cred, cred.Claims, owner, ErrNone
}
// checkAdminRequestAuth checks for authentication and authorization for the incoming
// request. It only accepts V2 and V4 requests. Presigned, JWT and anonymous requests
// are automatically rejected.
func checkAdminRequestAuth(ctx context.Context, r *http.Request, action iampolicy.AdminAction, region string) (auth.Credentials, APIErrorCode) {
cred, claims, owner, s3Err := validateAdminSignature(ctx, r, region)
if s3Err != ErrNone {
return cred, s3Err
}
if globalIAMSys.IsAllowed(iampolicy.Args{
AccountName: cred.AccessKey,
Groups: cred.Groups,
Action: iampolicy.Action(action),
ConditionValues: getConditionValues(r, "", cred.AccessKey, claims),
IsOwner: owner,
Claims: claims,
}) {
// Request is allowed return the appropriate access key.
return cred, ErrNone
}
return cred, ErrAccessDenied
}
// Fetch the security token set by the client.
func getSessionToken(r *http.Request) (token string) {
token = r.Header.Get(xhttp.AmzSecurityToken)
if token != "" {
return token
}
return r.Form.Get(xhttp.AmzSecurityToken)
}
// Fetch claims in the security token returned by the client, doesn't return
// errors - upon errors the returned claims map will be empty.
func mustGetClaimsFromToken(r *http.Request) map[string]interface{} {
claims, _ := getClaimsFromToken(getSessionToken(r))
return claims
}
// Fetch claims in the security token returned by the client.
func getClaimsFromToken(token string) (map[string]interface{}, error) {
if token == "" {
claims := xjwt.NewMapClaims()
return claims.Map(), nil
}
// JWT token for x-amz-security-token is signed with admin
// secret key, temporary credentials become invalid if
// server admin credentials change. This is done to ensure
// that clients cannot decode the token using the temp
// secret keys and generate an entirely new claim by essentially
// hijacking the policies. We need to make sure that this is
// based an admin credential such that token cannot be decoded
// on the client side and is treated like an opaque value.
claims, err := auth.ExtractClaims(token, globalActiveCred.SecretKey)
if err != nil {
return nil, errAuthentication
}
// If OPA is set, return without any further checks.
if globalPolicyOPA != nil {
return claims.Map(), nil
}
// Check if a session policy is set. If so, decode it here.
sp, spok := claims.Lookup(iampolicy.SessionPolicyName)
if spok {
// Looks like subpolicy is set and is a string, if set then its
// base64 encoded, decode it. Decoding fails reject such
// requests.
spBytes, err := base64.StdEncoding.DecodeString(sp)
if err != nil {
// Base64 decoding fails, we should log to indicate
// something is malforming the request sent by client.
logger.LogIf(GlobalContext, err, logger.Application)
return nil, errAuthentication
}
claims.MapClaims[iampolicy.SessionPolicyName] = string(spBytes)
}
return claims.Map(), nil
}
// Fetch claims in the security token returned by the client and validate the token.
func checkClaimsFromToken(r *http.Request, cred auth.Credentials) (map[string]interface{}, APIErrorCode) {
token := getSessionToken(r)
if token != "" && cred.AccessKey == "" {
return nil, ErrNoAccessKey
}
if cred.IsServiceAccount() && token == "" {
token = cred.SessionToken
}
if subtle.ConstantTimeCompare([]byte(token), []byte(cred.SessionToken)) != 1 {
return nil, ErrInvalidToken
}
claims, err := getClaimsFromToken(token)
if err != nil {
return nil, toAPIErrorCode(r.Context(), err)
}
return claims, ErrNone
}
// Check request auth type verifies the incoming http request
// - validates the request signature
// - validates the policy action if anonymous tests bucket policies if any,
// for authenticated requests validates IAM policies.
// returns APIErrorCode if any to be replied to the client.
func checkRequestAuthType(ctx context.Context, r *http.Request, action policy.Action, bucketName, objectName string) (s3Err APIErrorCode) {
_, _, s3Err = checkRequestAuthTypeCredential(ctx, r, action, bucketName, objectName)
return s3Err
}
// Check request auth type verifies the incoming http request
// - validates the request signature
// - validates the policy action if anonymous tests bucket policies if any,
// for authenticated requests validates IAM policies.
// returns APIErrorCode if any to be replied to the client.
// Additionally returns the accessKey used in the request, and if this request is by an admin.
func checkRequestAuthTypeCredential(ctx context.Context, r *http.Request, action policy.Action, bucketName, objectName string) (cred auth.Credentials, owner bool, s3Err APIErrorCode) {
switch getRequestAuthType(r) {
case authTypeUnknown, authTypeStreamingSigned:
return cred, owner, ErrSignatureVersionNotSupported
case authTypePresignedV2, authTypeSignedV2:
if s3Err = isReqAuthenticatedV2(r); s3Err != ErrNone {
return cred, owner, s3Err
}
cred, owner, s3Err = getReqAccessKeyV2(r)
case authTypeSigned, authTypePresigned:
region := globalSite.Region
switch action {
case policy.GetBucketLocationAction, policy.ListAllMyBucketsAction:
region = ""
}
if s3Err = isReqAuthenticated(ctx, r, region, serviceS3); s3Err != ErrNone {
return cred, owner, s3Err
}
cred, owner, s3Err = getReqAccessKeyV4(r, region, serviceS3)
}
if s3Err != ErrNone {
return cred, owner, s3Err
}
// LocationConstraint is valid only for CreateBucketAction.
var locationConstraint string
if action == policy.CreateBucketAction {
// To extract region from XML in request body, get copy of request body.
payload, err := ioutil.ReadAll(io.LimitReader(r.Body, maxLocationConstraintSize))
if err != nil {
logger.LogIf(ctx, err, logger.Application)
return cred, owner, ErrMalformedXML
}
// Populate payload to extract location constraint.
r.Body = ioutil.NopCloser(bytes.NewReader(payload))
var s3Error APIErrorCode
locationConstraint, s3Error = parseLocationConstraint(r)
if s3Error != ErrNone {
return cred, owner, s3Error
}
// Populate payload again to handle it in HTTP handler.
r.Body = ioutil.NopCloser(bytes.NewReader(payload))
}
if cred.AccessKey != "" {
logger.GetReqInfo(ctx).AccessKey = cred.AccessKey
}
if action != policy.ListAllMyBucketsAction && cred.AccessKey == "" {
// Anonymous checks are not meant for ListBuckets action
if globalPolicySys.IsAllowed(policy.Args{
AccountName: cred.AccessKey,
Action: action,
BucketName: bucketName,
ConditionValues: getConditionValues(r, locationConstraint, "", nil),
IsOwner: false,
ObjectName: objectName,
}) {
// Request is allowed return the appropriate access key.
return cred, owner, ErrNone
}
if action == policy.ListBucketVersionsAction {
// In AWS S3 s3:ListBucket permission is same as s3:ListBucketVersions permission
// verify as a fallback.
if globalPolicySys.IsAllowed(policy.Args{
AccountName: cred.AccessKey,
Action: policy.ListBucketAction,
BucketName: bucketName,
ConditionValues: getConditionValues(r, locationConstraint, "", nil),
IsOwner: false,
ObjectName: objectName,
}) {
// Request is allowed return the appropriate access key.
return cred, owner, ErrNone
}
}
return cred, owner, ErrAccessDenied
}
if globalIAMSys.IsAllowed(iampolicy.Args{
AccountName: cred.AccessKey,
Groups: cred.Groups,
Action: iampolicy.Action(action),
BucketName: bucketName,
ConditionValues: getConditionValues(r, "", cred.AccessKey, cred.Claims),
ObjectName: objectName,
IsOwner: owner,
Claims: cred.Claims,
}) {
// Request is allowed return the appropriate access key.
return cred, owner, ErrNone
}
if action == policy.ListBucketVersionsAction {
// In AWS S3 s3:ListBucket permission is same as s3:ListBucketVersions permission
// verify as a fallback.
if globalIAMSys.IsAllowed(iampolicy.Args{
AccountName: cred.AccessKey,
Groups: cred.Groups,
Action: iampolicy.ListBucketAction,
BucketName: bucketName,
ConditionValues: getConditionValues(r, "", cred.AccessKey, cred.Claims),
ObjectName: objectName,
IsOwner: owner,
Claims: cred.Claims,
}) {
// Request is allowed return the appropriate access key.
return cred, owner, ErrNone
}
}
return cred, owner, ErrAccessDenied
}
// Verify if request has valid AWS Signature Version '2'.
func isReqAuthenticatedV2(r *http.Request) (s3Error APIErrorCode) {
if isRequestSignatureV2(r) {
return doesSignV2Match(r)
}
return doesPresignV2SignatureMatch(r)
}
func reqSignatureV4Verify(r *http.Request, region string, stype serviceType) (s3Error APIErrorCode) {
sha256sum := getContentSha256Cksum(r, stype)
switch {
case isRequestSignatureV4(r):
return doesSignatureMatch(sha256sum, r, region, stype)
case isRequestPresignedSignatureV4(r):
return doesPresignedSignatureMatch(sha256sum, r, region, stype)
default:
return ErrAccessDenied
}
}
// Verify if request has valid AWS Signature Version '4'.
func isReqAuthenticated(ctx context.Context, r *http.Request, region string, stype serviceType) (s3Error APIErrorCode) {
if errCode := reqSignatureV4Verify(r, region, stype); errCode != ErrNone {
return errCode
}
clientETag, err := etag.FromContentMD5(r.Header)
if err != nil {
return ErrInvalidDigest
}
// Extract either 'X-Amz-Content-Sha256' header or 'X-Amz-Content-Sha256' query parameter (if V4 presigned)
// Do not verify 'X-Amz-Content-Sha256' if skipSHA256.
var contentSHA256 []byte
if skipSHA256 := skipContentSha256Cksum(r); !skipSHA256 && isRequestPresignedSignatureV4(r) {
if sha256Sum, ok := r.Form[xhttp.AmzContentSha256]; ok && len(sha256Sum) > 0 {
contentSHA256, err = hex.DecodeString(sha256Sum[0])
if err != nil {
return ErrContentSHA256Mismatch
}
}
} else if _, ok := r.Header[xhttp.AmzContentSha256]; !skipSHA256 && ok {
contentSHA256, err = hex.DecodeString(r.Header.Get(xhttp.AmzContentSha256))
if err != nil || len(contentSHA256) == 0 {
return ErrContentSHA256Mismatch
}
}
// Verify 'Content-Md5' and/or 'X-Amz-Content-Sha256' if present.
// The verification happens implicit during reading.
reader, err := hash.NewReader(r.Body, -1, clientETag.String(), hex.EncodeToString(contentSHA256), -1)
if err != nil {
return toAPIErrorCode(ctx, err)
}
r.Body = reader
return ErrNone
}
// List of all support S3 auth types.
var supportedS3AuthTypes = map[authType]struct{}{
authTypeAnonymous: {},
authTypePresigned: {},
authTypePresignedV2: {},
authTypeSigned: {},
authTypeSignedV2: {},
authTypePostPolicy: {},
authTypeStreamingSigned: {},
}
// Validate if the authType is valid and supported.
func isSupportedS3AuthType(aType authType) bool {
_, ok := supportedS3AuthTypes[aType]
return ok
}
// setAuthHandler to validate authorization header for the incoming request.
func setAuthHandler(h http.Handler) http.Handler {
// handler for validating incoming authorization headers.
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
aType := getRequestAuthType(r)
if aType == authTypeSigned || aType == authTypeSignedV2 || aType == authTypeStreamingSigned {
// Verify if date headers are set, if not reject the request
amzDate, errCode := parseAmzDateHeader(r)
if errCode != ErrNone {
// All our internal APIs are sensitive towards Date
// header, for all requests where Date header is not
// present we will reject such clients.
writeErrorResponse(r.Context(), w, errorCodes.ToAPIErr(errCode), r.URL)
atomic.AddUint64(&globalHTTPStats.rejectedRequestsTime, 1)
return
}
// Verify if the request date header is shifted by less than globalMaxSkewTime parameter in the past
// or in the future, reject request otherwise.
curTime := UTCNow()
if curTime.Sub(amzDate) > globalMaxSkewTime || amzDate.Sub(curTime) > globalMaxSkewTime {
writeErrorResponse(r.Context(), w, errorCodes.ToAPIErr(ErrRequestTimeTooSkewed), r.URL)
atomic.AddUint64(&globalHTTPStats.rejectedRequestsTime, 1)
return
}
}
if isSupportedS3AuthType(aType) || aType == authTypeJWT || aType == authTypeSTS {
h.ServeHTTP(w, r)
return
}
writeErrorResponse(r.Context(), w, errorCodes.ToAPIErr(ErrSignatureVersionNotSupported), r.URL)
atomic.AddUint64(&globalHTTPStats.rejectedRequestsAuth, 1)
})
}
func validateSignature(atype authType, r *http.Request) (auth.Credentials, bool, APIErrorCode) {
var cred auth.Credentials
var owner bool
var s3Err APIErrorCode
switch atype {
case authTypeUnknown, authTypeStreamingSigned:
return cred, owner, ErrSignatureVersionNotSupported
case authTypeSignedV2, authTypePresignedV2:
if s3Err = isReqAuthenticatedV2(r); s3Err != ErrNone {
return cred, owner, s3Err
}
cred, owner, s3Err = getReqAccessKeyV2(r)
case authTypePresigned, authTypeSigned:
region := globalSite.Region
if s3Err = isReqAuthenticated(GlobalContext, r, region, serviceS3); s3Err != ErrNone {
return cred, owner, s3Err
}
cred, owner, s3Err = getReqAccessKeyV4(r, region, serviceS3)
}
if s3Err != ErrNone {
return cred, owner, s3Err
}
return cred, owner, ErrNone
}
func isPutRetentionAllowed(bucketName, objectName string, retDays int, retDate time.Time, retMode objectlock.RetMode, byPassSet bool, r *http.Request, cred auth.Credentials, owner bool) (s3Err APIErrorCode) {
var retSet bool
if cred.AccessKey == "" {
return ErrAccessDenied
}
conditions := getConditionValues(r, "", cred.AccessKey, cred.Claims)
conditions["object-lock-mode"] = []string{string(retMode)}
conditions["object-lock-retain-until-date"] = []string{retDate.Format(time.RFC3339)}
if retDays > 0 {
conditions["object-lock-remaining-retention-days"] = []string{strconv.Itoa(retDays)}
}
if retMode == objectlock.RetGovernance && byPassSet {
byPassSet = globalIAMSys.IsAllowed(iampolicy.Args{
AccountName: cred.AccessKey,
Groups: cred.Groups,
Action: iampolicy.BypassGovernanceRetentionAction,
BucketName: bucketName,
ObjectName: objectName,
ConditionValues: conditions,
IsOwner: owner,
Claims: cred.Claims,
})
}
if globalIAMSys.IsAllowed(iampolicy.Args{
AccountName: cred.AccessKey,
Groups: cred.Groups,
Action: iampolicy.PutObjectRetentionAction,
BucketName: bucketName,
ConditionValues: conditions,
ObjectName: objectName,
IsOwner: owner,
Claims: cred.Claims,
}) {
retSet = true
}
if byPassSet || retSet {
return ErrNone
}
return ErrAccessDenied
}
// isPutActionAllowed - check if PUT operation is allowed on the resource, this
// call verifies bucket policies and IAM policies, supports multi user
// checks etc.
func isPutActionAllowed(ctx context.Context, atype authType, bucketName, objectName string, r *http.Request, action iampolicy.Action) (s3Err APIErrorCode) {
var cred auth.Credentials
var owner bool
switch atype {
case authTypeUnknown:
return ErrSignatureVersionNotSupported
case authTypeSignedV2, authTypePresignedV2:
cred, owner, s3Err = getReqAccessKeyV2(r)
case authTypeStreamingSigned, authTypePresigned, authTypeSigned:
region := globalSite.Region
cred, owner, s3Err = getReqAccessKeyV4(r, region, serviceS3)
}
if s3Err != ErrNone {
return s3Err
}
if cred.AccessKey != "" {
logger.GetReqInfo(ctx).AccessKey = cred.AccessKey
}
// Do not check for PutObjectRetentionAction permission,
// if mode and retain until date are not set.
// Can happen when bucket has default lock config set
if action == iampolicy.PutObjectRetentionAction &&
r.Header.Get(xhttp.AmzObjectLockMode) == "" &&
r.Header.Get(xhttp.AmzObjectLockRetainUntilDate) == "" {
return ErrNone
}
if cred.AccessKey == "" {
if globalPolicySys.IsAllowed(policy.Args{
AccountName: cred.AccessKey,
Groups: cred.Groups,
Action: policy.Action(action),
BucketName: bucketName,
ConditionValues: getConditionValues(r, "", "", nil),
IsOwner: false,
ObjectName: objectName,
}) {
return ErrNone
}
return ErrAccessDenied
}
if globalIAMSys.IsAllowed(iampolicy.Args{
AccountName: cred.AccessKey,
Groups: cred.Groups,
Action: action,
BucketName: bucketName,
ConditionValues: getConditionValues(r, "", cred.AccessKey, cred.Claims),
ObjectName: objectName,
IsOwner: owner,
Claims: cred.Claims,
}) {
return ErrNone
}
return ErrAccessDenied
}