From: Shelikhoo Date: Mon, 22 Feb 2021 13:20:36 +0000 Subject: Fix incorrect HMac Chaining, further checking needed (cherry picked from commit 0024c6e028768d8516bdee11be9834b2617ff00c) Closes: #1009818 --- proxy/vmess/aead/kdf.go | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-) diff --git a/proxy/vmess/aead/kdf.go b/proxy/vmess/aead/kdf.go index ebcea0a..5fc4ac5 100644 --- a/proxy/vmess/aead/kdf.go +++ b/proxy/vmess/aead/kdf.go @@ -7,17 +7,27 @@ import ( ) func KDF(key []byte, path ...string) []byte { - hmacf := hmac.New(sha256.New, []byte(KDFSaltConstVMessAEADKDF)) - + hmacCreator := &hMacCreator{value: []byte(KDFSaltConstVMessAEADKDF)} for _, v := range path { - hmacf = hmac.New(func() hash.Hash { - return hmacf - }, []byte(v)) + hmacCreator = &hMacCreator{value: []byte(v), parent: hmacCreator} } + hmacf := hmacCreator.Create() hmacf.Write(key) return hmacf.Sum(nil) } +type hMacCreator struct { + parent *hMacCreator + value []byte +} + +func (h *hMacCreator) Create() hash.Hash { + if h.parent == nil { + return hmac.New(sha256.New, h.value) + } + return hmac.New(h.parent.Create, h.value) +} + func KDF16(key []byte, path ...string) []byte { r := KDF(key, path...) return r[:16]