jws: split token into fixed number of parts
Thanks to 'jub0bs' for reporting this issue.
Fixes #71490
Fixes CVE-2025-22868
Change-Id: I2552731f46d4907f29aafe7863c558387b6bd6e2
Reviewed-on: https://go-review.googlesource.com/c/oauth2/+/652155
Auto-Submit: Gopher Robot <gobot@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Roland Shoemaker <roland@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
diff --git a/jws/jws.go b/jws/jws.go
index 9501564..6f03a49 100644
--- a/jws/jws.go
+++ b/jws/jws.go
@@ -165,11 +165,11 @@
// Verify tests whether the provided JWT token's signature was produced by the private key
// associated with the supplied public key.
func Verify(token string, key *rsa.PublicKey) error {
- parts := strings.Split(token, ".")
- if len(parts) != 3 {
+ if strings.Count(token, ".") != 2 {
return errors.New("jws: invalid token received, token must have 3 parts")
}
+ parts := strings.SplitN(token, ".", 3)
signedContent := parts[0] + "." + parts[1]
signatureString, err := base64.RawURLEncoding.DecodeString(parts[2])
if err != nil {
