Unit tests and code cleanup for cold storage

cmd/nonshy/main.go

@@ -204,8 +204,6 @@ func main() {
 							},
 						},
 						Action: func(c *cli.Context) error {
-							initdb(c)
-
 							err := coldstorage.FileFromColdStorage(
 								c.String("key"),
 								c.String("aes"),
@@ -213,7 +211,7 @@ func main() {
 								c.String("output"),
 							)
 							if err != nil {
-								log.Error("Error decrypting from cold storage: %s")
+								log.Error("Error decrypting from cold storage: %s", err)
 								return err
 							}
 

docs/Cold Storage.md

@@ -0,0 +1,70 @@
+# Cold Storage
+
+One of the security features of the website is **cold storage** which implements a "one way" encryption process for archiving sensitive files on the site.
+
+The first use case is to archive secondary photo IDs: if a user was requested to provide a scan of their government issued photo ID for approval, the site can archive the original copy to cold storage when approved in case of any future inquiry.
+
+The cold storage feature works by encrypting the file using an RSA public key, and relies on the matching private key to be **removed** from the web server and kept offline; so in case of a hack or data breach, the key that can decrypt the cold storage files will **NOT** be kept on the same web server.
+
+This document explains how this feature works and how to configure it.
+
+## Initialization
+
+When the server starts up and there is not a cold storage RSA key configured, the feature will be initialized by generating new RSA encryption keys:
+
+* The directory `./coldstorage/keys` is created and the RSA keys will be written in files named **private.pem** and **public.pem**.
+* The RSA public key is _also_ written into the **settings.json** file for the server, at the Encryption / ColdStorageRSAPublicKey property.
+
+You should **move the keys OFF of your web server machine** and keep them safe for your bookkeeping. Notably, the `private.pem` key is the sensitive file that should be removed.
+
+The app does not need either of these keys to remain on the server: the settings.json has a copy of the RSA public key which the app uses to create cold storage encrypted files.
+
+### Admin Dashboard Warning
+
+As a safety precaution: if the private.pem key remains on disk, a warning is shown at the top of the Admin Dashboard page of the website to remind you that the key should be removed and stored safely offline.
+
+## Recovering from Cold Storage
+
+Should you need to recover an encrypted file from cold storage, the `nonshy coldstorage decrypt` command built into the Go server binary has the function to decrypt the files.
+
+Every item that is moved into cold storage generates two files: an encrypted AES key file (`.aes`) and the encrypted data file itself (with a `.enc` extension). For example, a "photo.jpg" might go into cold storage as two files: "photo.jpg.aes" and "photo.jpg.enc"
+
+You will need the following three files to decrypt from cold storage:
+
+1. The RSA private key file (private.pem)
+2. The encrypted AES key file (.aes extension)
+3. The encrypted cold storage data file (.enc extension)
+
+The command to decrypt them is thus like:
+
+```bash
+# command example
+nonshy coldstorage decrypt \
+    --key private.pem \
+    --aes photo.jpg.aes \
+    --input photo.jpg.enc \
+    --output photo.jpg
+
+# short command line flags work too
+nonshy coldstorage decrypt -k private.pem \
+    -a photo.jpg.aes -i photo.jpg.enc \
+    -o photo.jpg
+```
+
+The `--output` file is where the decrypted file will be written to.
+
+## Encryption Algorithms
+
+When a file is moved into cold storage:
+
+1. A fresh new AES symmetric key is generated from scratch.
+2. The AES key is encrypted using the **RSA public key** and written to the ".aes" file in the coldstorage/ folder.
+3. The original file is encrypted using that AES symmetric key and written to the ".enc" file in the coldstorage/ folder.
+
+At the end of the encrypt function: the web server no longer has the AES key and is _unable_ to decrypt it because the private key is not available (as it should be kept offline for security).
+
+Decrypting a file out of cold storage is done like so:
+
+1. The encrypted AES key is unlocked using the **RSA private key**.
+2. The encrypted cold storage file (.enc) is decrypted with that AES key.
+3. The cleartext data is written to the output file.

pkg/config/variable.go

@@ -98,7 +98,7 @@ func LoadSettings() {
 		writeSettings = true
 	}
 
-	// Initialize the cold storage ECDSA keys.
+	// Initialize the cold storage RSA keys.
 	if len(Current.Encryption.ColdStorageRSAPublicKey) == 0 {
 		x509publicKey, err := coldstorage.Initialize()
 		if err != nil {

pkg/controller/photo/certification.go

@@ -472,10 +472,10 @@ func AdminCertification() http.HandlerFunc {
 				if cert.SecondaryFilename != "" {
 					// Move the original photo into cold storage.
 					coldStorageFilename := fmt.Sprintf(
-						"photoID-%d-%s-%s.jpg",
+						"photoID-%d-%s-%d.jpg",
 						user.ID,
 						user.Username,
-						time.Now().Format(time.RFC3339Nano),
+						time.Now().Unix(),
 					)
 					if err := coldstorage.FileToColdStorage(
 						photo.DiskPath(cert.SecondaryFilename),

pkg/encryption/keygen/aes.go

@@ -0,0 +1,72 @@
+// Package keygen provides the AES key initializer function.
+package keygen
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"errors"
+	"fmt"
+	"io"
+)
+
+// NewAESKey returns a 32-byte (AES 256 bit) encryption key.
+func NewAESKey() ([]byte, error) {
+	var result = make([]byte, 32)
+	_, err := rand.Read(result)
+	return result, err
+}
+
+// EncryptWithAESKey a byte stream using a given AES key.
+func EncryptWithAESKey(input []byte, key []byte) ([]byte, error) {
+	// Generate a new AES cipher.
+	c, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	// gcm or Galois/Counter Mode
+	gcm, err := cipher.NewGCM(c)
+	if err != nil {
+		return nil, err
+	}
+
+	// Create a new byte array the size of the GCM nonce
+	// which must be passed to Seal.
+	nonce := make([]byte, gcm.NonceSize())
+	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
+		return nil, fmt.Errorf("populating the nonce: %s", err)
+	}
+
+	// Encrypt the text using the Seal function.
+	// Seal encrypts and authenticates plaintext, authenticates the
+	// additional data and appends the result to dst, returning the
+	// updated slice. The nonce must be NonceSize() bytes long and
+	// unique for all time, for a given key.
+	result := gcm.Seal(nonce, nonce, input, nil)
+	return result, nil
+}
+
+func DecryptWithAESKey(data []byte, key []byte) ([]byte, error) {
+	c, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, err
+	}
+
+	gcm, err := cipher.NewGCM(c)
+	if err != nil {
+		return nil, err
+	}
+
+	nonceSize := gcm.NonceSize()
+	if len(data) < nonceSize {
+		return nil, errors.New("ciphertext data less than nonceSize")
+	}
+
+	nonce, ciphertext := data[:nonceSize], data[nonceSize:]
+	plaintext, err := gcm.Open(nil, nonce, ciphertext, nil)
+	if err != nil {
+		return nil, err
+	}
+	return plaintext, nil
+}

pkg/encryption/keygen/aes_test.go

@@ -0,0 +1,72 @@
+package keygen_test
+
+import (
+	"testing"
+
+	"code.nonshy.com/nonshy/website/pkg/encryption/keygen"
+)
+
+func TestAES(t *testing.T) {
+	type testCase struct {
+		AESKey    []byte // AES key, nil = generate a new one
+		Input     []byte // input text to encrypt
+		Encrypted []byte // already encrypted text
+		Expect    []byte // expected output on decrypt
+	}
+
+	var tests = []testCase{
+		{
+			Input:  []byte("hello world"),
+			Expect: []byte("hello world"),
+		},
+		{
+			AESKey:    []byte{170, 94, 243, 132, 85, 247, 149, 238, 245, 39, 140, 125, 226, 178, 134, 161, 17, 151, 139, 248, 16, 94, 165, 8, 102, 238, 214, 183, 86, 138, 219, 52},
+			Encrypted: []byte{146, 217, 250, 254, 70, 201, 27, 221, 92, 145, 77, 213, 211, 197, 63, 189, 220, 188, 78, 8, 217, 108, 136, 89, 156, 23, 179, 54, 209, 54, 244, 170, 182, 150, 242, 52, 112, 191, 216, 46},
+			Expect:    []byte("goodbye mars"),
+		},
+	}
+
+	for i, test := range tests {
+		if len(test.AESKey) == 0 {
+			key, err := keygen.NewAESKey()
+			if err != nil {
+				t.Errorf("Test #%d: failed to generate new AES key: %s", i, err)
+				continue
+			}
+			test.AESKey = key
+		}
+
+		if len(test.Encrypted) == 0 {
+			enc, err := keygen.EncryptWithAESKey(test.Input, test.AESKey)
+			if err != nil {
+				t.Errorf("Test #%d: failed to encrypt input: %s", i, err)
+				continue
+			}
+			test.Encrypted = enc
+		}
+
+		// t.Errorf("Key: %+v\nEnc: %+v", test.AESKey, test.Encrypted)
+
+		dec, err := keygen.DecryptWithAESKey(test.Encrypted, test.AESKey)
+		if err != nil {
+			t.Errorf("Test #%d: failed to decrypt: %s", i, err)
+			continue
+		}
+
+		// compare the results
+		var ok = true
+		if len(dec) != len(test.Expect) {
+			ok = false
+		} else {
+			for j := range dec {
+				if test.Expect[j] != dec[j] {
+					ok = false
+				}
+			}
+		}
+		if !ok {
+			t.Errorf("Test #%d: got unexpected result from decrypt. Expected %s, got %s", i, test.Expect, dec)
+			continue
+		}
+	}
+}

pkg/encryption/keygen/rsa.go

@@ -3,81 +3,15 @@ package keygen
 
 import (
 	"crypto"
-	"crypto/aes"
-	"crypto/cipher"
 	"crypto/rand"
 	"crypto/rsa"
 	"crypto/x509"
 	"encoding/pem"
-	"errors"
-	"fmt"
-	"io"
 	"os"
 
 	"code.nonshy.com/nonshy/website/pkg/log"
 )
 
-// NewAESKey returns a 32-byte (AES 256 bit) encryption key.
-func NewAESKey() ([]byte, error) {
-	var result = make([]byte, 32)
-	_, err := rand.Read(result)
-	return result, err
-}
-
-// EncryptWithAESKey a byte stream using a given AES key.
-func EncryptWithAESKey(input []byte, key []byte) ([]byte, error) {
-	// Generate a new AES cipher.
-	c, err := aes.NewCipher(key)
-	if err != nil {
-		return nil, err
-	}
-
-	// gcm or Galois/Counter Mode
-	gcm, err := cipher.NewGCM(c)
-	if err != nil {
-		return nil, err
-	}
-
-	// Create a new byte array the size of the GCM nonce
-	// which must be passed to Seal.
-	nonce := make([]byte, gcm.NonceSize())
-	if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
-		return nil, fmt.Errorf("populating the nonce: %s", err)
-	}
-
-	// Encrypt the text using the Seal function.
-	// Seal encrypts and authenticates plaintext, authenticates the
-	// additional data and appends the result to dst, returning the
-	// updated slice. The nonce must be NonceSize() bytes long and
-	// unique for all time, for a given key.
-	result := gcm.Seal(nonce, nonce, input, nil)
-	return result, nil
-}
-
-func DecryptWithAESKey(data []byte, key []byte) ([]byte, error) {
-	c, err := aes.NewCipher(key)
-	if err != nil {
-		return nil, err
-	}
-
-	gcm, err := cipher.NewGCM(c)
-	if err != nil {
-		return nil, err
-	}
-
-	nonceSize := gcm.NonceSize()
-	if len(data) < nonceSize {
-		return nil, errors.New("ciphertext data less than nonceSize")
-	}
-
-	nonce, ciphertext := data[:nonceSize], data[nonceSize:]
-	plaintext, err := gcm.Open(nil, nonce, ciphertext, nil)
-	if err != nil {
-		return nil, err
-	}
-	return plaintext, nil
-}
-
 // NewRSAKeys will generate an RSA 2048-bit key pair.
 func NewRSAKeys() (*rsa.PrivateKey, error) {
 	privateKey, err := rsa.GenerateKey(rand.Reader, 2048)