wrap errors

[govpn.git] / src / cypherpunks.ru / govpn / aont / oaep.go

diff --git a/src/cypherpunks.ru/govpn/aont/oaep.go b/src/cypherpunks.ru/govpn/aont/oaep.go
index a2329a3dd28187a3dc6a83cd64de946cbada643b..7431060fa0a6b3bb1dabdd0a0ab12a75b8239269 100644 (file)
--- a/src/cypherpunks.ru/govpn/aont/oaep.go
+++ b/src/cypherpunks.ru/govpn/aont/oaep.go
@@ -36,9 +36,9 @@ package aont
 
 import (
        "crypto/subtle"
-       "errors"
 
        "chacha20"
+       "github.com/pkg/errors"
        "golang.org/x/crypto/blake2b"
 )
 
@@ -47,6 +47,9 @@ const (
        HSize = 32
        // RSize size of generated random output in terms of OAEP
        RSize = 16
+
+       wrapBlake2bNew256 = "blake2b.New256"
+       wrapHashWrite     = "hash.Write"
 )
 
 var (
@@ -60,16 +63,22 @@ func Encode(r *[RSize]byte, in []byte) ([]byte, error) {
        copy(out, in)
        h, err := blake2b.New256(nil)
        if err != nil {
-               return nil, err
+               return nil, errors.Wrap(err, wrapBlake2bNew256)
+       }
+       if _, err = h.Write(r[:]); err != nil {
+               return nil, errors.Wrap(err, wrapHashWrite)
+       }
+       if _, err = h.Write(in); err != nil {
+               return nil, errors.Wrap(err, wrapHashWrite)
        }
-       h.Write(r[:])
-       h.Write(in)
        copy(out[len(in):], h.Sum(nil))
        chachaKey := new([32]byte)
        copy(chachaKey[:], r[:])
        chacha20.XORKeyStream(out, out, dummyNonce, chachaKey)
        h.Reset()
-       h.Write(out[:len(in)+32])
+       if _, err = h.Write(out[:len(in)+32]); err != nil {
+               return nil, errors.Wrap(err, wrapHashWrite)
+       }
        for i, b := range h.Sum(nil)[:RSize] {
                out[len(in)+32+i] = b ^ r[i]
        }
@@ -84,18 +93,24 @@ func Decode(in []byte) ([]byte, error) {
        }
        h, err := blake2b.New256(nil)
        if err != nil {
-               return nil, err
+               return nil, errors.Wrap(err, wrapBlake2bNew256)
+       }
+       if _, err = h.Write(in[:len(in)-RSize]); err != nil {
+               return nil, errors.Wrap(err, wrapHashWrite)
        }
-       h.Write(in[:len(in)-RSize])
        chachaKey := new([32]byte)
        for i, b := range h.Sum(nil)[:RSize] {
                chachaKey[i] = b ^ in[len(in)-RSize+i]
        }
        h.Reset()
-       h.Write(chachaKey[:RSize])
+       if _, err = h.Write(chachaKey[:RSize]); err != nil {
+               return nil, errors.Wrap(err, wrapHashWrite)
+       }
        out := make([]byte, len(in)-RSize)
        chacha20.XORKeyStream(out, in[:len(in)-RSize], dummyNonce, chachaKey)
-       h.Write(out[:len(out)-HSize])
+       if _, err = h.Write(out[:len(out)-HSize]); err != nil {
+               return nil, errors.Wrap(err, wrapHashWrite)
+       }
        if subtle.ConstantTimeCompare(h.Sum(nil), out[len(out)-HSize:]) != 1 {
                return nil, errors.New("Invalid checksum")
        }