crypto: improve error messages in LoadECDSA

cmd/geth/accountcmd_test.go

@@ -17,6 +17,7 @@
 package main
 
 import (
+	"fmt"
 	"io/ioutil"
 	"path/filepath"
 	"runtime"
@@ -88,6 +89,40 @@ Path of the secret key file: .*UTC--.+--[0-9a-f]{40}
 `)
 }
 
+func TestAccountImport(t *testing.T) {
+	success := "Address: {fcad0b19bb29d4674531d6f115237e16afce377c}\n"
+	failureTemplate := "Fatal: Failed to load the private key: expected 64 bytes, got %v\n"
+	tests := []struct {
+		key    string
+		result string
+	}{
+		{key: "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef", result: success},
+		{key: "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\n", result: success},
+		{key: "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\r\n", result: success},
+		{key: "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef1", result: fmt.Sprintf(failureTemplate, 65)},
+		{key: "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdefx", result: fmt.Sprintf(failureTemplate, 65)},
+		{key: "0123456789abcdef0123456789abcdef0123456789abcdef0123456789abcdef\n\n\n", result: fmt.Sprintf(failureTemplate, 67)},
+	}
+	for _, test := range tests {
+		importAccountWithExpect(t, test.key, test.result)
+	}
+}
+
+func importAccountWithExpect(t *testing.T, key string, expected string) {
+	dir := tmpdir(t)
+	keyfile := filepath.Join(dir, "key.prv")
+	if err := ioutil.WriteFile(keyfile, []byte(key), 0644); err != nil {
+		t.Error(err)
+	}
+	passwordFile := filepath.Join(dir, "password.txt")
+	if err := ioutil.WriteFile(passwordFile, []byte("foobar"), 0644); err != nil {
+		t.Error(err)
+	}
+	geth := runGeth(t, "account", "import", keyfile, "-password", passwordFile)
+	defer geth.ExpectExit()
+	geth.Expect(expected)
+}
+
 func TestAccountNewBadRepeat(t *testing.T) {
 	geth := runGeth(t, "account", "new", "--lightkdf")
 	defer geth.ExpectExit()

crypto/crypto.go

@@ -17,13 +17,13 @@
 package crypto
 
 import (
+	"bytes"
 	"crypto/ecdsa"
 	"crypto/elliptic"
 	"crypto/rand"
 	"encoding/hex"
 	"errors"
 	"fmt"
-	"io"
 	"io/ioutil"
 	"math/big"
 	"os"
@@ -166,15 +166,23 @@ func HexToECDSA(hexkey string) (*ecdsa.PrivateKey, error) {
 
 // LoadECDSA loads a secp256k1 private key from the given file.
 func LoadECDSA(file string) (*ecdsa.PrivateKey, error) {
-	buf := make([]byte, 64)
-	fd, err := os.Open(file)
+	stat, err := os.Stat(file)
 	if err != nil {
 		return nil, err
 	}
-	defer fd.Close()
-	if _, err := io.ReadFull(fd, buf); err != nil {
+	size := stat.Size()
+	// Allow two extra chars for possible line ending to be checked later
+	if size < 64 || size > 66 {
+		return nil, fmt.Errorf("expected 64 bytes, got %v", size)
+	}
+	buf, err := ioutil.ReadFile(file)
+	if err != nil {
 		return nil, err
 	}
+	buf = bytes.TrimSpace(buf)
+	if len(buf) != 64 {
+		return nil, fmt.Errorf("expected 64 bytes, got %v", len(buf))
+	}
 
 	key, err := hex.DecodeString(string(buf))
 	if err != nil {