remove panics [squash]

Length checks are already carried out at the entry points into fat error
encryption/decryption.

Author: joostjager

fat_error_decrypt.go

@@ -154,10 +154,6 @@ const (
 )
 
 func (o *OnionFatErrorDecrypter) shiftHmacsLeft(hmacs []byte) {
-	if len(hmacs) != o.allHmacsLen {
-		panic("invalid hmac block length")
-	}
-
 	srcIdx := o.maxHops
 	destIdx := 1
 	copyLen := o.maxHops - 1
@@ -174,10 +170,6 @@ func (o *OnionFatErrorDecrypter) shiftHmacsLeft(hmacs []byte) {
 }
 
 func (o *OnionFatErrorDecrypter) shiftPayloadsLeft(payloads []byte) {
-	if len(payloads) != o.allPayloadsLen {
-		panic("invalid payload block length")
-	}
-
 	copy(payloads, payloads[o.payloadLen:o.maxHops*o.payloadLen])
 }
 

fat_error_encrypt.go

@@ -26,10 +26,6 @@ type OnionFatErrorEncrypter struct {
 }
 
 func (o *OnionFatErrorEncrypter) shiftHmacsRight(hmacs []byte) {
-	if len(hmacs) != o.allHmacsLen {
-		panic("invalid hmac block length")
-	}
-
 	srcIdx := o.totalHmacs - 2
 	destIdx := o.totalHmacs - 1
 	copyLen := 1
@@ -47,10 +43,6 @@ func (o *OnionFatErrorEncrypter) shiftHmacsRight(hmacs []byte) {
 }
 
 func (o *OnionFatErrorEncrypter) shiftPayloadsRight(payloads []byte) {
-	if len(payloads) != o.allPayloadsLen {
-		panic("invalid payload block length")
-	}
-
 	copy(payloads[o.payloadLen:], payloads)
 }