frostfs-s3-gw/api/auth/center.go

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package auth
import (
"context"
"crypto/hmac"
"crypto/sha256"
"encoding/hex"
"fmt"
"io"
"mime/multipart"
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"net/http"
"regexp"
"strings"
"time"
v4 "git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/auth/signer/v4"
apiErrors "git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/errors"
"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/middleware"
"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/creds/accessbox"
"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/creds/tokens"
oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
"github.com/aws/aws-sdk-go/aws/credentials"
)
// authorizationFieldRegexp -- is regexp for credentials with Base58 encoded cid and oid and '0' (zero) as delimiter.
var authorizationFieldRegexp = regexp.MustCompile(`AWS4-HMAC-SHA256 Credential=(?P<access_key_id>[^/]+)/(?P<date>[^/]+)/(?P<region>[^/]*)/(?P<service>[^/]+)/aws4_request,\s*SignedHeaders=(?P<signed_header_fields>.+),\s*Signature=(?P<v4_signature>.+)`)
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// postPolicyCredentialRegexp -- is regexp for credentials when uploading file using POST with policy.
var postPolicyCredentialRegexp = regexp.MustCompile(`(?P<access_key_id>[^/]+)/(?P<date>[^/]+)/(?P<region>[^/]*)/(?P<service>[^/]+)/aws4_request`)
type (
Center struct {
reg *RegexpSubmatcher
postReg *RegexpSubmatcher
cli tokens.Credentials
allowedAccessKeyIDPrefixes []string // empty slice means all access key ids are allowed
}
//nolint:revive
AuthHeader struct {
AccessKeyID string
Service string
Region string
SignatureV4 string
SignedFields []string
Date string
IsPresigned bool
Expiration time.Duration
}
)
const (
accessKeyPartsNum = 2
authHeaderPartsNum = 6
maxFormSizeMemory = 50 * 1048576 // 50 MB
AmzAlgorithm = "X-Amz-Algorithm"
AmzCredential = "X-Amz-Credential"
AmzSignature = "X-Amz-Signature"
AmzSignedHeaders = "X-Amz-SignedHeaders"
AmzExpires = "X-Amz-Expires"
AmzDate = "X-Amz-Date"
AmzContentSHA256 = "X-Amz-Content-Sha256"
AuthorizationHdr = "Authorization"
ContentTypeHdr = "Content-Type"
UnsignedPayload = "UNSIGNED-PAYLOAD"
StreamingUnsignedPayloadTrailer = "STREAMING-UNSIGNED-PAYLOAD-TRAILER"
StreamingContentSHA256 = "STREAMING-AWS4-HMAC-SHA256-PAYLOAD"
StreamingContentSHA256Trailer = "STREAMING-AWS4-HMAC-SHA256-PAYLOAD-TRAILER"
StreamingContentECDSASHA256 = "STREAMING-AWS4-ECDSA-P256-SHA256-PAYLOAD"
StreamingContentECDSASHA256Trailer = "STREAMING-AWS4-ECDSA-P256-SHA256-PAYLOAD-TRAILER"
)
var ContentSHA256HeaderStandardValue = map[string]struct{}{
UnsignedPayload: {},
StreamingUnsignedPayloadTrailer: {},
StreamingContentSHA256: {},
StreamingContentSHA256Trailer: {},
StreamingContentECDSASHA256: {},
StreamingContentECDSASHA256Trailer: {},
}
// New creates an instance of AuthCenter.
func New(creds tokens.Credentials, prefixes []string) *Center {
return &Center{
cli: creds,
reg: NewRegexpMatcher(authorizationFieldRegexp),
postReg: NewRegexpMatcher(postPolicyCredentialRegexp),
allowedAccessKeyIDPrefixes: prefixes,
}
}
func (c *Center) parseAuthHeader(header string) (*AuthHeader, error) {
submatches := c.reg.GetSubmatches(header)
if len(submatches) != authHeaderPartsNum {
return nil, fmt.Errorf("%w: %s", apiErrors.GetAPIError(apiErrors.ErrAuthorizationHeaderMalformed), header)
}
accessKey := strings.Split(submatches["access_key_id"], "0")
if len(accessKey) != accessKeyPartsNum {
return nil, fmt.Errorf("%w: %s", apiErrors.GetAPIError(apiErrors.ErrInvalidAccessKeyID), accessKey)
}
signedFields := strings.Split(submatches["signed_header_fields"], ";")
return &AuthHeader{
AccessKeyID: submatches["access_key_id"],
Service: submatches["service"],
Region: submatches["region"],
SignatureV4: submatches["v4_signature"],
SignedFields: signedFields,
Date: submatches["date"],
}, nil
}
func getAddress(accessKeyID string) (oid.Address, error) {
var addr oid.Address
if err := addr.DecodeString(strings.ReplaceAll(accessKeyID, "0", "/")); err != nil {
return addr, fmt.Errorf("%w: %s", apiErrors.GetAPIError(apiErrors.ErrInvalidAccessKeyID), accessKeyID)
}
return addr, nil
}
func IsStandardContentSHA256(key string) bool {
_, ok := ContentSHA256HeaderStandardValue[key]
return ok
}
func (c *Center) Authenticate(r *http.Request) (*middleware.Box, error) {
var (
err error
authHdr *AuthHeader
signatureDateTimeStr string
needClientTime bool
)
queryValues := r.URL.Query()
if queryValues.Get(AmzAlgorithm) == "AWS4-HMAC-SHA256" {
creds := strings.Split(queryValues.Get(AmzCredential), "/")
if len(creds) != 5 || creds[4] != "aws4_request" {
return nil, fmt.Errorf("bad X-Amz-Credential")
}
authHdr = &AuthHeader{
AccessKeyID: creds[0],
Service: creds[3],
Region: creds[2],
SignatureV4: queryValues.Get(AmzSignature),
SignedFields: strings.Split(queryValues.Get(AmzSignedHeaders), ";"),
Date: creds[1],
IsPresigned: true,
}
authHdr.Expiration, err = time.ParseDuration(queryValues.Get(AmzExpires) + "s")
if err != nil {
return nil, fmt.Errorf("couldn't parse X-Amz-Expires: %w", err)
}
signatureDateTimeStr = queryValues.Get(AmzDate)
} else {
authHeaderField := r.Header[AuthorizationHdr]
if len(authHeaderField) != 1 {
if strings.HasPrefix(r.Header.Get(ContentTypeHdr), "multipart/form-data") {
return c.checkFormData(r)
}
return nil, fmt.Errorf("%w: %v", middleware.ErrNoAuthorizationHeader, authHeaderField)
}
authHdr, err = c.parseAuthHeader(authHeaderField[0])
if err != nil {
return nil, err
}
signatureDateTimeStr = r.Header.Get(AmzDate)
needClientTime = true
}
signatureDateTime, err := time.Parse("20060102T150405Z", signatureDateTimeStr)
if err != nil {
return nil, fmt.Errorf("failed to parse x-amz-date header field: %w", err)
}
if err = c.checkAccessKeyID(authHdr.AccessKeyID); err != nil {
return nil, err
}
addr, err := getAddress(authHdr.AccessKeyID)
if err != nil {
return nil, err
}
box, attrs, err := c.cli.GetBox(r.Context(), addr)
if err != nil {
return nil, fmt.Errorf("get box '%s': %w", addr, err)
}
if err = checkFormatHashContentSHA256(r.Header.Get(AmzContentSHA256)); err != nil {
return nil, err
}
clonedRequest := cloneRequest(r, authHdr)
if err = c.checkSign(authHdr, box, clonedRequest, signatureDateTime); err != nil {
return nil, err
}
result := &middleware.Box{
AccessBox: box,
AuthHeaders: &middleware.AuthHeader{
AccessKeyID: authHdr.AccessKeyID,
Region: authHdr.Region,
SignatureV4: authHdr.SignatureV4,
},
Attributes: attrs,
}
if needClientTime {
result.ClientTime = signatureDateTime
}
return result, nil
}
func checkFormatHashContentSHA256(hash string) error {
if !IsStandardContentSHA256(hash) {
hashBinary, err := hex.DecodeString(hash)
if err != nil {
return fmt.Errorf("%w: decode hash: %s: %s", apiErrors.GetAPIError(apiErrors.ErrContentSHA256Mismatch),
hash, err.Error())
}
if len(hashBinary) != sha256.Size && len(hash) != 0 {
return fmt.Errorf("%w: invalid hash size %d", apiErrors.GetAPIError(apiErrors.ErrContentSHA256Mismatch), len(hashBinary))
}
}
return nil
}
func (c Center) checkAccessKeyID(accessKeyID string) error {
if len(c.allowedAccessKeyIDPrefixes) == 0 {
return nil
}
for _, prefix := range c.allowedAccessKeyIDPrefixes {
if strings.HasPrefix(accessKeyID, prefix) {
return nil
}
}
return fmt.Errorf("%w: accesskeyID prefix isn't allowed", apiErrors.GetAPIError(apiErrors.ErrAccessDenied))
}
func (c *Center) checkFormData(r *http.Request) (*middleware.Box, error) {
if err := r.ParseMultipartForm(maxFormSizeMemory); err != nil {
return nil, fmt.Errorf("%w: parse multipart form with max size %d", apiErrors.GetAPIError(apiErrors.ErrInvalidArgument), maxFormSizeMemory)
}
if err := prepareForm(r.MultipartForm); err != nil {
return nil, fmt.Errorf("couldn't parse form: %w", err)
}
policy := MultipartFormValue(r, "policy")
if policy == "" {
return nil, fmt.Errorf("%w: missing policy", middleware.ErrNoAuthorizationHeader)
}
creds := MultipartFormValue(r, "x-amz-credential")
submatches := c.postReg.GetSubmatches(creds)
if len(submatches) != 4 {
return nil, fmt.Errorf("%w: %s", apiErrors.GetAPIError(apiErrors.ErrAuthorizationHeaderMalformed), creds)
}
signatureDateTime, err := time.Parse("20060102T150405Z", MultipartFormValue(r, "x-amz-date"))
if err != nil {
return nil, fmt.Errorf("failed to parse x-amz-date field: %w", err)
}
addr, err := getAddress(submatches["access_key_id"])
if err != nil {
return nil, err
}
box, attrs, err := c.cli.GetBox(r.Context(), addr)
if err != nil {
return nil, fmt.Errorf("get box '%s': %w", addr, err)
}
secret := box.Gate.SecretKey
service, region := submatches["service"], submatches["region"]
signature := signStr(secret, service, region, signatureDateTime, policy)
reqSignature := MultipartFormValue(r, "x-amz-signature")
if signature != reqSignature {
return nil, fmt.Errorf("%w: %s != %s", apiErrors.GetAPIError(apiErrors.ErrSignatureDoesNotMatch),
reqSignature, signature)
}
return &middleware.Box{AccessBox: box, Attributes: attrs}, nil
}
func cloneRequest(r *http.Request, authHeader *AuthHeader) *http.Request {
otherRequest := r.Clone(context.TODO())
otherRequest.Header = make(http.Header)
for key, val := range r.Header {
for _, name := range authHeader.SignedFields {
if strings.EqualFold(key, name) {
otherRequest.Header[key] = val
}
}
}
if authHeader.IsPresigned {
otherQuery := otherRequest.URL.Query()
otherQuery.Del(AmzSignature)
otherRequest.URL.RawQuery = otherQuery.Encode()
}
return otherRequest
}
func (c *Center) checkSign(authHeader *AuthHeader, box *accessbox.Box, request *http.Request, signatureDateTime time.Time) error {
awsCreds := credentials.NewStaticCredentials(authHeader.AccessKeyID, box.Gate.SecretKey, "")
signer := v4.NewSigner(awsCreds)
signer.DisableURIPathEscaping = true
var signature string
if authHeader.IsPresigned {
now := time.Now()
if signatureDateTime.Add(authHeader.Expiration).Before(now) {
return fmt.Errorf("%w: expired: now %s, signature %s", apiErrors.GetAPIError(apiErrors.ErrExpiredPresignRequest),
now.Format(time.RFC3339), signatureDateTime.Format(time.RFC3339))
}
if now.Before(signatureDateTime) {
return fmt.Errorf("%w: signature time from the future: now %s, signature %s", apiErrors.GetAPIError(apiErrors.ErrBadRequest),
now.Format(time.RFC3339), signatureDateTime.Format(time.RFC3339))
}
if _, err := signer.Presign(request, nil, authHeader.Service, authHeader.Region, authHeader.Expiration, signatureDateTime); err != nil {
return fmt.Errorf("failed to pre-sign temporary HTTP request: %w", err)
}
signature = request.URL.Query().Get(AmzSignature)
} else {
if _, err := signer.Sign(request, nil, authHeader.Service, authHeader.Region, signatureDateTime); err != nil {
return fmt.Errorf("failed to sign temporary HTTP request: %w", err)
}
signature = c.reg.GetSubmatches(request.Header.Get(AuthorizationHdr))["v4_signature"]
}
if authHeader.SignatureV4 != signature {
return fmt.Errorf("%w: %s != %s: headers %v", apiErrors.GetAPIError(apiErrors.ErrSignatureDoesNotMatch),
authHeader.SignatureV4, signature, authHeader.SignedFields)
}
return nil
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}
func signStr(secret, service, region string, t time.Time, strToSign string) string {
creds := deriveKey(secret, service, region, t)
signature := hmacSHA256(creds, []byte(strToSign))
return hex.EncodeToString(signature)
}
func deriveKey(secret, service, region string, t time.Time) []byte {
hmacDate := hmacSHA256([]byte("AWS4"+secret), []byte(t.UTC().Format("20060102")))
hmacRegion := hmacSHA256(hmacDate, []byte(region))
hmacService := hmacSHA256(hmacRegion, []byte(service))
return hmacSHA256(hmacService, []byte("aws4_request"))
}
func hmacSHA256(key []byte, data []byte) []byte {
hash := hmac.New(sha256.New, key)
hash.Write(data)
return hash.Sum(nil)
}
// MultipartFormValue gets value by key from multipart form.
func MultipartFormValue(r *http.Request, key string) string {
if r.MultipartForm == nil {
return ""
}
if vs := r.MultipartForm.Value[key]; len(vs) > 0 {
return vs[0]
}
return ""
}
func prepareForm(form *multipart.Form) error {
var oldKeysValue []string
var oldKeysFile []string
for k, v := range form.Value {
lowerKey := strings.ToLower(k)
if lowerKey != k {
form.Value[lowerKey] = v
oldKeysValue = append(oldKeysValue, k)
}
}
for _, k := range oldKeysValue {
delete(form.Value, k)
}
for k, v := range form.File {
lowerKey := strings.ToLower(k)
if lowerKey != "file" {
oldKeysFile = append(oldKeysFile, k)
if len(v) > 0 {
field, err := v[0].Open()
if err != nil {
return fmt.Errorf("file header open: %w", err)
}
data, err := io.ReadAll(field)
if err != nil {
return fmt.Errorf("read field: %w", err)
}
form.Value[lowerKey] = []string{string(data)}
}
} else if lowerKey != k {
form.File[lowerKey] = v
oldKeysFile = append(oldKeysFile, k)
}
}
for _, k := range oldKeysFile {
delete(form.File, k)
}
return nil
}