401 lines
11 KiB
Go
401 lines
11 KiB
Go
package auth
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import (
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"context"
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"crypto/hmac"
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"crypto/sha256"
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"encoding/hex"
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"errors"
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"fmt"
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"io"
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"mime/multipart"
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"net/http"
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"regexp"
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"strings"
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"time"
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v4 "git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/auth/signer/v4"
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"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/cache"
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apiErrors "git.frostfs.info/TrueCloudLab/frostfs-s3-gw/api/errors"
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"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/creds/accessbox"
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"git.frostfs.info/TrueCloudLab/frostfs-s3-gw/creds/tokens"
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oid "git.frostfs.info/TrueCloudLab/frostfs-sdk-go/object/id"
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"github.com/aws/aws-sdk-go/aws/credentials"
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"github.com/nspcc-dev/neo-go/pkg/crypto/keys"
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)
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// authorizationFieldRegexp -- is regexp for credentials with Base58 encoded cid and oid and '0' (zero) as delimiter.
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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.
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var postPolicyCredentialRegexp = regexp.MustCompile(`(?P<access_key_id>[^/]+)/(?P<date>[^/]+)/(?P<region>[^/]*)/(?P<service>[^/]+)/aws4_request`)
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type (
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// Center is a user authentication interface.
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Center interface {
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Authenticate(request *http.Request) (*Box, error)
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}
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// Box contains access box and additional info.
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Box struct {
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AccessBox *accessbox.Box
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ClientTime time.Time
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AuthHeaders *AuthHeader
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}
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center struct {
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reg *RegexpSubmatcher
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postReg *RegexpSubmatcher
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cli tokens.Credentials
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allowedAccessKeyIDPrefixes []string // empty slice means all access key ids are allowed
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}
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prs int
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//nolint:revive
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AuthHeader struct {
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AccessKeyID string
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Service string
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Region string
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SignatureV4 string
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SignedFields []string
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Date string
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IsPresigned bool
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Expiration time.Duration
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}
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)
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const (
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accessKeyPartsNum = 2
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authHeaderPartsNum = 6
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maxFormSizeMemory = 50 * 1048576 // 50 MB
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AmzAlgorithm = "X-Amz-Algorithm"
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AmzCredential = "X-Amz-Credential"
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AmzSignature = "X-Amz-Signature"
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AmzSignedHeaders = "X-Amz-SignedHeaders"
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AmzExpires = "X-Amz-Expires"
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AmzDate = "X-Amz-Date"
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AuthorizationHdr = "Authorization"
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ContentTypeHdr = "Content-Type"
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)
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// ErrNoAuthorizationHeader is returned for unauthenticated requests.
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var ErrNoAuthorizationHeader = errors.New("no authorization header")
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func (p prs) Read(_ []byte) (n int, err error) {
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panic("implement me")
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}
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func (p prs) Seek(_ int64, _ int) (int64, error) {
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panic("implement me")
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}
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var _ io.ReadSeeker = prs(0)
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// New creates an instance of AuthCenter.
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func New(frostFS tokens.FrostFS, key *keys.PrivateKey, prefixes []string, config *cache.Config) Center {
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return ¢er{
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cli: tokens.New(frostFS, key, config),
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reg: NewRegexpMatcher(authorizationFieldRegexp),
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postReg: NewRegexpMatcher(postPolicyCredentialRegexp),
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allowedAccessKeyIDPrefixes: prefixes,
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}
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}
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func (c *center) parseAuthHeader(header string) (*AuthHeader, error) {
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submatches := c.reg.GetSubmatches(header)
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if len(submatches) != authHeaderPartsNum {
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return nil, apiErrors.GetAPIError(apiErrors.ErrAuthorizationHeaderMalformed)
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}
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accessKey := strings.Split(submatches["access_key_id"], "0")
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if len(accessKey) != accessKeyPartsNum {
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return nil, apiErrors.GetAPIError(apiErrors.ErrInvalidAccessKeyID)
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}
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signedFields := strings.Split(submatches["signed_header_fields"], ";")
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return &AuthHeader{
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AccessKeyID: submatches["access_key_id"],
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Service: submatches["service"],
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Region: submatches["region"],
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SignatureV4: submatches["v4_signature"],
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SignedFields: signedFields,
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Date: submatches["date"],
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}, nil
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}
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func (a *AuthHeader) getAddress() (oid.Address, error) {
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var addr oid.Address
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if err := addr.DecodeString(strings.ReplaceAll(a.AccessKeyID, "0", "/")); err != nil {
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return addr, apiErrors.GetAPIError(apiErrors.ErrInvalidAccessKeyID)
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}
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return addr, nil
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}
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func (c *center) Authenticate(r *http.Request) (*Box, error) {
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var (
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err error
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authHdr *AuthHeader
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signatureDateTimeStr string
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needClientTime bool
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)
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queryValues := r.URL.Query()
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if queryValues.Get(AmzAlgorithm) == "AWS4-HMAC-SHA256" {
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creds := strings.Split(queryValues.Get(AmzCredential), "/")
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if len(creds) != 5 || creds[4] != "aws4_request" {
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return nil, fmt.Errorf("bad X-Amz-Credential")
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}
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authHdr = &AuthHeader{
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AccessKeyID: creds[0],
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Service: creds[3],
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Region: creds[2],
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SignatureV4: queryValues.Get(AmzSignature),
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SignedFields: strings.Split(queryValues.Get(AmzSignedHeaders), ";"),
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Date: creds[1],
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IsPresigned: true,
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}
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authHdr.Expiration, err = time.ParseDuration(queryValues.Get(AmzExpires) + "s")
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if err != nil {
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return nil, fmt.Errorf("couldn't parse X-Amz-Expires: %w", err)
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}
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signatureDateTimeStr = queryValues.Get(AmzDate)
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} else {
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authHeaderField := r.Header[AuthorizationHdr]
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if len(authHeaderField) != 1 {
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if strings.HasPrefix(r.Header.Get(ContentTypeHdr), "multipart/form-data") {
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return c.checkFormData(r)
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}
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return nil, ErrNoAuthorizationHeader
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}
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authHdr, err = c.parseAuthHeader(authHeaderField[0])
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if err != nil {
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return nil, err
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}
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signatureDateTimeStr = r.Header.Get(AmzDate)
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needClientTime = true
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}
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signatureDateTime, err := time.Parse("20060102T150405Z", signatureDateTimeStr)
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if err != nil {
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return nil, fmt.Errorf("failed to parse x-amz-date header field: %w", err)
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}
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if err := c.checkAccessKeyID(authHdr.AccessKeyID); err != nil {
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return nil, err
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}
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addr, err := authHdr.getAddress()
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if err != nil {
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return nil, err
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}
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box, err := c.cli.GetBox(r.Context(), addr)
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if err != nil {
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return nil, fmt.Errorf("get box: %w", err)
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}
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clonedRequest := cloneRequest(r, authHdr)
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if err = c.checkSign(authHdr, box, clonedRequest, signatureDateTime); err != nil {
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return nil, err
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}
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result := &Box{
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AccessBox: box,
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AuthHeaders: authHdr,
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}
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if needClientTime {
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result.ClientTime = signatureDateTime
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}
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return result, nil
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}
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func (c center) checkAccessKeyID(accessKeyID string) error {
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if len(c.allowedAccessKeyIDPrefixes) == 0 {
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return nil
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}
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for _, prefix := range c.allowedAccessKeyIDPrefixes {
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if strings.HasPrefix(accessKeyID, prefix) {
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return nil
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}
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}
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return apiErrors.GetAPIError(apiErrors.ErrAccessDenied)
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}
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func (c *center) checkFormData(r *http.Request) (*Box, error) {
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if err := r.ParseMultipartForm(maxFormSizeMemory); err != nil {
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return nil, apiErrors.GetAPIError(apiErrors.ErrInvalidArgument)
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}
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if err := prepareForm(r.MultipartForm); err != nil {
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return nil, fmt.Errorf("couldn't parse form: %w", err)
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}
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policy := MultipartFormValue(r, "policy")
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if policy == "" {
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return nil, ErrNoAuthorizationHeader
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}
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submatches := c.postReg.GetSubmatches(MultipartFormValue(r, "x-amz-credential"))
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if len(submatches) != 4 {
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return nil, apiErrors.GetAPIError(apiErrors.ErrAuthorizationHeaderMalformed)
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}
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signatureDateTime, err := time.Parse("20060102T150405Z", MultipartFormValue(r, "x-amz-date"))
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if err != nil {
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return nil, fmt.Errorf("failed to parse x-amz-date field: %w", err)
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}
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var addr oid.Address
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if err = addr.DecodeString(strings.ReplaceAll(submatches["access_key_id"], "0", "/")); err != nil {
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return nil, apiErrors.GetAPIError(apiErrors.ErrInvalidAccessKeyID)
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}
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box, err := c.cli.GetBox(r.Context(), addr)
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if err != nil {
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return nil, fmt.Errorf("get box: %w", err)
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}
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secret := box.Gate.AccessKey
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service, region := submatches["service"], submatches["region"]
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signature := signStr(secret, service, region, signatureDateTime, policy)
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if signature != MultipartFormValue(r, "x-amz-signature") {
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return nil, apiErrors.GetAPIError(apiErrors.ErrSignatureDoesNotMatch)
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}
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return &Box{AccessBox: box}, nil
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}
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func cloneRequest(r *http.Request, authHeader *AuthHeader) *http.Request {
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otherRequest := r.Clone(context.TODO())
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otherRequest.Header = make(http.Header)
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for key, val := range r.Header {
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for _, name := range authHeader.SignedFields {
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if strings.EqualFold(key, name) {
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otherRequest.Header[key] = val
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}
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}
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}
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if authHeader.IsPresigned {
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otherQuery := otherRequest.URL.Query()
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otherQuery.Del(AmzSignature)
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otherRequest.URL.RawQuery = otherQuery.Encode()
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}
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return otherRequest
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}
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func (c *center) checkSign(authHeader *AuthHeader, box *accessbox.Box, request *http.Request, signatureDateTime time.Time) error {
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awsCreds := credentials.NewStaticCredentials(authHeader.AccessKeyID, box.Gate.AccessKey, "")
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signer := v4.NewSigner(awsCreds)
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signer.DisableURIPathEscaping = true
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var signature string
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if authHeader.IsPresigned {
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now := time.Now()
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if signatureDateTime.Add(authHeader.Expiration).Before(now) {
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return apiErrors.GetAPIError(apiErrors.ErrExpiredPresignRequest)
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}
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if now.Before(signatureDateTime) {
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return apiErrors.GetAPIError(apiErrors.ErrBadRequest)
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}
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if _, err := signer.Presign(request, nil, authHeader.Service, authHeader.Region, authHeader.Expiration, signatureDateTime); err != nil {
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return fmt.Errorf("failed to pre-sign temporary HTTP request: %w", err)
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}
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signature = request.URL.Query().Get(AmzSignature)
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} else {
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if _, err := signer.Sign(request, nil, authHeader.Service, authHeader.Region, signatureDateTime); err != nil {
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return fmt.Errorf("failed to sign temporary HTTP request: %w", err)
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}
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signature = c.reg.GetSubmatches(request.Header.Get(AuthorizationHdr))["v4_signature"]
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}
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if authHeader.SignatureV4 != signature {
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return apiErrors.GetAPIError(apiErrors.ErrSignatureDoesNotMatch)
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}
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return nil
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}
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func signStr(secret, service, region string, t time.Time, strToSign string) string {
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creds := deriveKey(secret, service, region, t)
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signature := hmacSHA256(creds, []byte(strToSign))
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return hex.EncodeToString(signature)
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}
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func deriveKey(secret, service, region string, t time.Time) []byte {
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hmacDate := hmacSHA256([]byte("AWS4"+secret), []byte(t.UTC().Format("20060102")))
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hmacRegion := hmacSHA256(hmacDate, []byte(region))
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hmacService := hmacSHA256(hmacRegion, []byte(service))
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return hmacSHA256(hmacService, []byte("aws4_request"))
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}
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func hmacSHA256(key []byte, data []byte) []byte {
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hash := hmac.New(sha256.New, key)
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hash.Write(data)
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return hash.Sum(nil)
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}
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// MultipartFormValue gets value by key from multipart form.
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func MultipartFormValue(r *http.Request, key string) string {
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if r.MultipartForm == nil {
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return ""
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}
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if vs := r.MultipartForm.Value[key]; len(vs) > 0 {
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return vs[0]
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}
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return ""
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}
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func prepareForm(form *multipart.Form) error {
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var oldKeysValue []string
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var oldKeysFile []string
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for k, v := range form.Value {
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lowerKey := strings.ToLower(k)
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if lowerKey != k {
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form.Value[lowerKey] = v
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oldKeysValue = append(oldKeysValue, k)
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}
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}
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for _, k := range oldKeysValue {
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delete(form.Value, k)
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}
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for k, v := range form.File {
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lowerKey := strings.ToLower(k)
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if lowerKey != "file" {
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oldKeysFile = append(oldKeysFile, k)
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if len(v) > 0 {
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field, err := v[0].Open()
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if err != nil {
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return fmt.Errorf("file header open: %w", err)
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}
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data, err := io.ReadAll(field)
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if err != nil {
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return fmt.Errorf("read field: %w", err)
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}
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form.Value[lowerKey] = []string{string(data)}
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}
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} else if lowerKey != k {
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form.File[lowerKey] = v
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oldKeysFile = append(oldKeysFile, k)
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}
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}
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for _, k := range oldKeysFile {
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delete(form.File, k)
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}
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return nil
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}
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