From dbfadc5a7e5bd3163b49878994063cd6d869fe6a Mon Sep 17 00:00:00 2001 From: Runxi Yu Date: Mon, 24 Mar 2025 21:47:40 +0800 Subject: Refactor --- identifier.go | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) (limited to 'identifier.go') diff --git a/identifier.go b/identifier.go index 4b15f0f..88d2be3 100644 --- a/identifier.go +++ b/identifier.go @@ -6,11 +6,15 @@ package main import ( "crypto/hmac" "crypto/sha256" + "crypto/subtle" + "encoding/base64" "encoding/binary" "net/http" "time" ) +// makeIdentifierMAC generates an identifier that semi-uniquely identifies the client, +// and generates a MAC for that identifier. func makeIdentifierMAC(request *http.Request) (identifier []byte, mac []byte) { identifier = make([]byte, 0, sha256.Size) mac = make([]byte, 0, sha256.Size) @@ -37,3 +41,18 @@ func makeIdentifierMAC(request *http.Request) (identifier []byte, mac []byte) { return } + +// validateCookie checks if the cookie is valid by comparing the base64-decoded +// value of the cookie with an expected MAC. +func validateCookie(cookie *http.Cookie, expectedMAC []byte) bool { + if cookie == nil { + return false + } + + gotMAC, err := base64.StdEncoding.DecodeString(cookie.Value) + if err != nil { + return false + } + + return subtle.ConstantTimeCompare(gotMAC, expectedMAC) == 1 +} -- cgit v1.2.3