From: Sergey Matveev <stargrave@stargrave.org>
Date: Wed, 5 Apr 2023 11:21:15 +0000 (+0300)
Subject: Slightly refactored error messages
X-Git-Tag: v5.10.0~5
X-Git-Url: http://www.git.cypherpunks.ru/?p=gogost.git;a=commitdiff_plain;h=c19a111af499e05273906e9d5f7c059ab38d6f02

Slightly refactored error messages
---

diff --git a/gost28147/mac.go b/gost28147/mac.go
index a5a0487..71e8039 100644
--- a/gost28147/mac.go
+++ b/gost28147/mac.go
@@ -16,7 +16,7 @@
 package gost28147
 
 import (
-	"errors"
+	"fmt"
 )
 
 var (
@@ -42,10 +42,10 @@ type MAC struct {
 // following ones are fed to Write function.
 func (c *Cipher) NewMAC(size int, iv []byte) (*MAC, error) {
 	if size == 0 || size > 8 {
-		return nil, errors.New("gogost/gost28147: invalid tag size")
+		return nil, fmt.Errorf("gogost/gost28147: invalid tag size (0<%d<=8)", size)
 	}
 	if len(iv) != BlockSize {
-		return nil, errors.New("gogost/gost28147: len(iv) != 8")
+		return nil, fmt.Errorf("gogost/gost28147: len(iv)=%d != %d", len(iv), BlockSize)
 	}
 	m := MAC{c: c, size: size, iv: iv}
 	n2, n1 := block2nvs(iv)
diff --git a/gost3410/private.go b/gost3410/private.go
index f51096f..7629563 100644
--- a/gost3410/private.go
+++ b/gost3410/private.go
@@ -31,7 +31,7 @@ type PrivateKey struct {
 func NewPrivateKey(c *Curve, raw []byte) (*PrivateKey, error) {
 	pointSize := c.PointSize()
 	if len(raw) != pointSize {
-		return nil, fmt.Errorf("gogost/gost3410: len(key) != %d", pointSize)
+		return nil, fmt.Errorf("gogost/gost3410: len(key)=%d != %d", len(raw), pointSize)
 	}
 	key := make([]byte, pointSize)
 	for i := 0; i < len(key); i++ {
@@ -47,7 +47,7 @@ func NewPrivateKey(c *Curve, raw []byte) (*PrivateKey, error) {
 func GenPrivateKey(c *Curve, rand io.Reader) (*PrivateKey, error) {
 	raw := make([]byte, c.PointSize())
 	if _, err := io.ReadFull(rand, raw); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("gogost/gost3410.GenPrivateKey: %w", err)
 	}
 	return NewPrivateKey(c, raw)
 }
@@ -61,7 +61,7 @@ func (prv *PrivateKey) Raw() []byte {
 func (prv *PrivateKey) PublicKey() (*PublicKey, error) {
 	x, y, err := prv.C.Exp(prv.Key, prv.C.X, prv.C.Y)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("gogost/gost3410.PrivateKey.PublicKey: %w", err)
 	}
 	return &PublicKey{prv.C, x, y}, nil
 }
@@ -80,7 +80,7 @@ func (prv *PrivateKey) SignDigest(digest []byte, rand io.Reader) ([]byte, error)
 	s := big.NewInt(0)
 Retry:
 	if _, err = io.ReadFull(rand, kRaw); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("gogost/gost3410.PrivateKey.SignDigest: %w", err)
 	}
 	k = bytes2big(kRaw)
 	k.Mod(k, prv.C.Q)
@@ -89,7 +89,7 @@ Retry:
 	}
 	r, _, err = prv.C.Exp(k, prv.C.X, prv.C.Y)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("gogost/gost3410.PrivateKey.SignDigest: %w", err)
 	}
 	r.Mod(r, prv.C.Q)
 	if r.Cmp(zero) == 0 {
diff --git a/gost3410/public.go b/gost3410/public.go
index ea1906d..957293e 100644
--- a/gost3410/public.go
+++ b/gost3410/public.go
@@ -56,7 +56,7 @@ func (pub *PublicKey) Raw() []byte {
 func (pub *PublicKey) VerifyDigest(digest, signature []byte) (bool, error) {
 	pointSize := pub.C.PointSize()
 	if len(signature) != 2*pointSize {
-		return false, fmt.Errorf("gogost/gost3410: len(signature) != %d", 2*pointSize)
+		return false, fmt.Errorf("gogost/gost3410: len(signature)=%d != %d", len(signature), 2*pointSize)
 	}
 	s := bytes2big(signature[:pointSize])
 	r := bytes2big(signature[pointSize:])
diff --git a/gost3410/vko.go b/gost3410/vko.go
index 88d0a26..c0afa99 100644
--- a/gost3410/vko.go
+++ b/gost3410/vko.go
@@ -16,19 +16,20 @@
 package gost3410
 
 import (
+	"fmt"
 	"math/big"
 )
 
 func (prv *PrivateKey) KEK(pub *PublicKey, ukm *big.Int) ([]byte, error) {
 	keyX, keyY, err := prv.C.Exp(prv.Key, pub.X, pub.Y)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("gogost/gost3410.PrivateKey.KEK: %w", err)
 	}
 	u := big.NewInt(0).Set(ukm).Mul(ukm, prv.C.Co)
 	if u.Cmp(bigInt1) != 0 {
 		keyX, keyY, err = prv.C.Exp(u, keyX, keyY)
 		if err != nil {
-			return nil, err
+			return nil, fmt.Errorf("gogost/gost3410.PrivateKey.KEK: %w", err)
 		}
 	}
 	pk := PublicKey{prv.C, keyX, keyY}
diff --git a/gost3410/vko2001.go b/gost3410/vko2001.go
index 6d8fbf6..fd944b1 100644
--- a/gost3410/vko2001.go
+++ b/gost3410/vko2001.go
@@ -17,6 +17,7 @@ package gost3410
 
 import (
 	"errors"
+	"fmt"
 	"math/big"
 
 	"go.cypherpunks.ru/gogost/v5/gost28147"
@@ -31,11 +32,11 @@ func (prv *PrivateKey) KEK2001(pub *PublicKey, ukm *big.Int) ([]byte, error) {
 	}
 	key, err := prv.KEK(pub, ukm)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("gogost/gost3410.PrivateKey.KEK2001: %w", err)
 	}
 	h := gost341194.New(&gost28147.SboxIdGostR341194CryptoProParamSet)
 	if _, err = h.Write(key); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("gogost/gost3410.PrivateKey.KEK2001: %w", err)
 	}
 	return h.Sum(key[:0]), nil
 }
diff --git a/gost3410/vko2012.go b/gost3410/vko2012.go
index b452768..0875e19 100644
--- a/gost3410/vko2012.go
+++ b/gost3410/vko2012.go
@@ -16,6 +16,7 @@
 package gost3410
 
 import (
+	"fmt"
 	"math/big"
 
 	"go.cypherpunks.ru/gogost/v5/gost34112012256"
@@ -27,11 +28,11 @@ import (
 func (prv *PrivateKey) KEK2012256(pub *PublicKey, ukm *big.Int) ([]byte, error) {
 	key, err := prv.KEK(pub, ukm)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("gogost/gost3410.PrivateKey.KEK2012256: %w", err)
 	}
 	h := gost34112012256.New()
 	if _, err = h.Write(key); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("gogost/gost3410.PrivateKey.KEK2012256: %w", err)
 	}
 	return h.Sum(key[:0]), nil
 }
@@ -41,11 +42,11 @@ func (prv *PrivateKey) KEK2012256(pub *PublicKey, ukm *big.Int) ([]byte, error)
 func (prv *PrivateKey) KEK2012512(pub *PublicKey, ukm *big.Int) ([]byte, error) {
 	key, err := prv.KEK(pub, ukm)
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("gogost/gost3410.PrivateKey.KEK2012256: %w", err)
 	}
 	h := gost34112012512.New()
 	if _, err = h.Write(key); err != nil {
-		return nil, err
+		return nil, fmt.Errorf("gogost/gost3410.PrivateKey.KEK2012256: %w", err)
 	}
 	return h.Sum(key[:0]), nil
 }
diff --git a/internal/gost34112012/hash.go b/internal/gost34112012/hash.go
index 6d56ca0..0e6d02a 100644
--- a/internal/gost34112012/hash.go
+++ b/internal/gost34112012/hash.go
@@ -452,7 +452,7 @@ func (h *Hash) MarshalBinary() (data []byte, err error) {
 func (h *Hash) UnmarshalBinary(data []byte) error {
 	expectedLen := len(MarshaledName) + 1 + 8 + 2*BlockSize
 	if len(data) < expectedLen {
-		return fmt.Errorf("gogost/internal/gost34112012: len(data) != %d", expectedLen)
+		return fmt.Errorf("gogost/internal/gost34112012: len(data)=%d != %d", len(data), expectedLen)
 	}
 	if !bytes.HasPrefix(data, []byte(MarshaledName)) {
 		return errors.New("gogost/internal/gost34112012: no hash name prefix")
diff --git a/mgm/mode.go b/mgm/mode.go
index 3fdeaba..50abfd4 100644
--- a/mgm/mode.go
+++ b/mgm/mode.go
@@ -21,6 +21,7 @@ import (
 	"crypto/hmac"
 	"encoding/binary"
 	"errors"
+	"fmt"
 )
 
 var InvalidTag = errors.New("gogost/mgm: invalid authentication tag")
@@ -45,10 +46,10 @@ type MGM struct {
 func NewMGM(cipher cipher.Block, tagSize int) (cipher.AEAD, error) {
 	blockSize := cipher.BlockSize()
 	if !(blockSize == 8 || blockSize == 16) {
-		return nil, errors.New("gogost/mgm: only 64/128 blocksizes allowed")
+		return nil, errors.New("gogost/mgm: only {64|128} blocksizes allowed")
 	}
 	if tagSize < 4 || tagSize > blockSize {
-		return nil, errors.New("gogost/mgm: invalid tag size")
+		return nil, fmt.Errorf("gogost/mgm: invalid tag size (4<=%d<=%d)", tagSize, blockSize)
 	}
 	mgm := MGM{
 		MaxSize:   uint64(1<<uint(blockSize*8/2) - 1),
@@ -215,7 +216,7 @@ func (mgm *MGM) Open(dst, nonce, ciphertext, additionalData []byte) ([]byte, err
 	mgm.validateNonce(nonce)
 	mgm.validateSizes(ciphertext, additionalData)
 	if len(ciphertext) < mgm.TagSize {
-		return nil, errors.New("ciphertext is too short")
+		return nil, fmt.Errorf("ciphertext is too short (%d<%d)", len(ciphertext), mgm.TagSize)
 	}
 	if uint64(len(ciphertext)-mgm.TagSize) > mgm.MaxSize {
 		panic("ciphertext is too big")