From c99412d11ee91a9e36e868d2614ab66d8609887c Mon Sep 17 00:00:00 2001
From: Nick Craig-Wood <nick@craig-wood.com>
Date: Mon, 19 Feb 2018 17:37:07 +0000
Subject: [PATCH] cryptcheck: make reading of nonce more efficient with
RangeOption #1825
...also only calculate the required hash which will speed things up slightly.
---
backend/crypt/crypt.go | 21 +++++++++++++++------
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/backend/crypt/crypt.go b/backend/crypt/crypt.go
index 23753c9b8..415fc4c6b 100644
--- a/backend/crypt/crypt.go
+++ b/backend/crypt/crypt.go
@@ -465,11 +465,17 @@ func (f *Fs) DecryptFileName(encryptedFileName string) (string, error) {
// Note that we break lots of encapsulation in this function.
func (f *Fs) ComputeHash(o *Object, src fs.Object, hashType hash.Type) (hashStr string, err error) {
// Read the nonce - opening the file is sufficient to read the nonce in
- in, err := o.Open()
+ // use a limited read so we only read the header
+ in, err := o.Object.Open(&fs.RangeOption{Start: 0, End: int64(fileHeaderSize) - 1})
if err != nil {
- return "", errors.Wrap(err, "failed to read nonce")
+ return "", errors.Wrap(err, "failed to open object to read nonce")
}
- nonce := in.(*decrypter).nonce
+ d, err := f.cipher.(*cipher).newDecrypter(in)
+ if err != nil {
+ _ = in.Close()
+ return "", errors.Wrap(err, "failed to open object to read nonce")
+ }
+ nonce := d.nonce
// fs.Debugf(o, "Read nonce % 2x", nonce)
// Check nonce isn't all zeros
@@ -483,8 +489,8 @@ func (f *Fs) ComputeHash(o *Object, src fs.Object, hashType hash.Type) (hashStr
fs.Errorf(o, "empty nonce read")
}
- // Close in once we have read the nonce
- err = in.Close()
+ // Close d (and hence in) once we have read the nonce
+ err = d.Close()
if err != nil {
return "", errors.Wrap(err, "failed to close nonce read")
}
@@ -503,7 +509,10 @@ func (f *Fs) ComputeHash(o *Object, src fs.Object, hashType hash.Type) (hashStr
}
// pipe into hash
- m := hash.NewMultiHasher()
+ m, err := hash.NewMultiHasherTypes(hash.NewHashSet(hashType))
+ if err != nil {
+ return "", errors.Wrap(err, "failed to make hasher")
+ }
_, err = io.Copy(m, out)
if err != nil {
return "", errors.Wrap(err, "failed to hash data")