-/*
-Permissions management on Arvados locator hashes.
-
-The permissions structure for Arvados is as follows (from
-https://arvados.org/issues/2328)
-
-A Keep locator string has the following format:
-
- [hash]+[size]+A[signature]@[timestamp]
-
-The "signature" string here is a cryptographic hash, expressed as a
-string of hexadecimal digits, and timestamp is a 32-bit Unix timestamp
-expressed as a hexadecimal number. e.g.:
-
- acbd18db4cc2f85cedef654fccc4a4d8+3+A257f3f5f5f0a4e4626a18fc74bd42ec34dcb228a@7fffffff
-
-The signature represents a guarantee that this locator was generated
-by either Keep or the API server for use with the supplied API token.
-If a request to Keep includes a locator with a valid signature and is
-accompanied by the proper API token, the user has permission to GET
-that object.
-
-The signature may be generated either by Keep (after the user writes a
-block) or by the API server (if the user has can_read permission on
-the specified object). Keep and API server share a secret that is used
-to generate signatures.
-
-To verify a permission hint, Keep generates a new hint for the
-requested object (using the locator string, the timestamp, the
-permission secret and the user's API token, which must appear in the
-request headers) and compares it against the hint included in the
-request. If the permissions do not match, or if the API token is not
-present, Keep returns a 401 error.
-*/
+// Copyright (C) The Arvados Authors. All rights reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
package keepclient
-import (
- "crypto/hmac"
- "crypto/sha1"
- "fmt"
- "regexp"
- "strconv"
- "strings"
- "time"
-)
-
-// KeepError types.
-//
-type KeepError struct {
- HTTPCode int
- ErrMsg string
-}
+import "git.arvados.org/arvados.git/sdk/go/arvados"
var (
- PermissionError = &KeepError{403, "Forbidden"}
- ExpiredError = &KeepError{401, "Expired permission signature"}
+ ErrSignatureExpired = arvados.ErrSignatureExpired
+ ErrSignatureInvalid = arvados.ErrSignatureInvalid
+ ErrSignatureMissing = arvados.ErrSignatureMissing
+ SignLocator = arvados.SignLocator
+ SignedLocatorRe = arvados.SignedLocatorRe
+ VerifySignature = arvados.VerifySignature
)
-
-func (e *KeepError) Error() string {
- return e.ErrMsg
-}
-
-// makePermSignature returns a string representing the signed permission
-// hint for the blob identified by blobHash, apiToken, expiration timestamp, and permission secret.
-//
-// The permissionSecret is the secret key used to generate SHA1 digests
-// for permission hints. apiserver and Keep must use the same key.
-func makePermSignature(blobHash string, apiToken string, expiry string, permissionSecret []byte) string {
- hmac := hmac.New(sha1.New, permissionSecret)
- hmac.Write([]byte(blobHash))
- hmac.Write([]byte("@"))
- hmac.Write([]byte(apiToken))
- hmac.Write([]byte("@"))
- hmac.Write([]byte(expiry))
- digest := hmac.Sum(nil)
- return fmt.Sprintf("%x", digest)
-}
-
-// SignLocator takes a blobLocator, an apiToken, an expiry time, and a permission secret
-// and returns a signed locator string.
-func SignLocator(blobLocator string, apiToken string, expiry time.Time, permissionSecret []byte) string {
- // If no permission secret or API token is available,
- // return an unsigned locator.
- if permissionSecret == nil || apiToken == "" {
- return blobLocator
- }
- // Extract the hash from the blob locator, omitting any size hint that may be present.
- blobHash := strings.Split(blobLocator, "+")[0]
- // Return the signed locator string.
- timestampHex := fmt.Sprintf("%08x", expiry.Unix())
- return blobLocator +
- "+A" + makePermSignature(blobHash, apiToken, timestampHex, permissionSecret) +
- "@" + timestampHex
-}
-
-var signedLocatorRe = regexp.MustCompile(`^([[:xdigit:]]{32}).*\+A([[:xdigit:]]{40})@([[:xdigit:]]{8})`)
-
-// VerifySignature returns nil if the signature on the signedLocator
-// can be verified using the given apiToken. Otherwise it returns
-// either ExpiredError (if the timestamp has expired, which is
-// something the client could have figured out independently) or
-// PermissionError.
-func VerifySignature(signedLocator string, apiToken string, permissionSecret []byte) error {
- matches := signedLocatorRe.FindStringSubmatch(signedLocator)
- if matches == nil {
- // Could not find a permission signature at all
- return PermissionError
- }
- blobHash := matches[1]
- sigHex := matches[2]
- expHex := matches[3]
- if expTime, err := parseHexTimestamp(expHex); err != nil {
- return PermissionError
- } else if expTime.Before(time.Now()) {
- return ExpiredError
- }
- if sigHex != makePermSignature(blobHash, apiToken, expHex, permissionSecret) {
- return PermissionError
- }
- return nil
-}
-
-// parseHexTimestamp parses timestamp
-func parseHexTimestamp(timestampHex string) (ts time.Time, err error) {
- if tsInt, e := strconv.ParseInt(timestampHex, 16, 0); e == nil {
- ts = time.Unix(tsInt, 0)
- } else {
- err = e
- }
- return ts, err
-}
projects / arvados.git / blobdiff