src/backup/crypt_setup.rs: allow compressed and uncompressed chunks

src/backup.rs

@@ -109,12 +109,17 @@ macro_rules! PROXMOX_BACKUP_PROTOCOL_ID_V1 {
 
 // WARNING: PLEASE DO NOT MODIFY THOSE MAGIC VALUES
 
-// openssl::sha::sha256(b"Proxmox Backup encrypted chunk v1.0")[0..8])
+// openssl::sha::sha256(b"Proxmox Backup uncompressed chunk v1.0")[0..8]
+pub static UNCOMPRESSED_CHUNK_MAGIC_1_0: [u8; 8] = [79, 127, 200, 4, 121, 74, 135, 239];
+
+// openssl::sha::sha256(b"Proxmox Backup encrypted chunk v1.0")[0..8]
 pub static ENCRYPTED_CHUNK_MAGIC_1_0: [u8; 8] = [8, 54, 114, 153, 70, 156, 26, 151];
 
 // openssl::sha::sha256(b"Proxmox Backup zstd compressed chunk v1.0")[0..8]
 pub static COMPRESSED_CHUNK_MAGIC_1_0: [u8; 8] = [191, 237, 46, 195, 108, 17, 228, 235];
 
+// openssl::sha::sha256(b"Proxmox Backup zstd compressed encrypted chunk v1.0")[0..8]
+pub static ENCR_COMPR_CHUNK_MAGIC_1_0: [u8; 8] = [9, 40, 53, 200, 37, 150, 90, 196];
 
 mod crypt_setup;
 pub use crypt_setup::*;

src/backup/crypt_setup.rs

@@ -10,7 +10,7 @@ use failure::*;
 use proxmox::tools;
 use openssl::pkcs5::{pbkdf2_hmac, scrypt};
 use openssl::hash::MessageDigest;
-use openssl::symm::{Cipher, Crypter, Mode};
+use openssl::symm::{encrypt_aead, decrypt_aead, Cipher, Crypter, Mode};
 use std::io::{Read, Write};
 
 /// Encryption Configuration with secret key
@@ -92,16 +92,22 @@ impl CryptConfig {
     /// Compress and encrypt data using a random 16 byte IV.
     ///
     /// Return the encrypted data, including IV and MAC (MAGIC || IV || MAC || ENC_DATA).
-    pub fn encode_chunk(&self, data: &[u8]) -> Result<Vec<u8>, Error> {
+    pub fn encode_chunk(&self, data: &[u8], compress: bool) -> Result<Vec<u8>, Error> {
 
         let iv = proxmox::sys::linux::random_data(16)?;
 
         let mut enc = Vec::with_capacity(data.len()+40+self.cipher.block_size());
 
+        if compress {
+            enc.write_all(&super::ENCR_COMPR_CHUNK_MAGIC_1_0)?;
+        } else {
             enc.write_all(&super::ENCRYPTED_CHUNK_MAGIC_1_0)?;
+        }
+
         enc.write_all(&iv)?;
         enc.write_all(&[0u8;16])?; // dummy tag, update later
 
+        if compress {
             let mut zstream = zstd::stream::read::Encoder::new(data, 1)?;
 
             let mut c = Crypter::new(self.cipher, Mode::Encrypt, &self.enc_key, Some(&iv))?;
@@ -126,6 +132,17 @@ impl CryptConfig {
             c.get_tag(&mut enc[24..40])?;
 
             Ok(enc)
+        } else {
+            encrypt_aead(
+                self.cipher,
+                &self.enc_key,
+                Some(&iv),
+                b"", //??
+                data,
+                &mut enc[24..40],
+            )?;
+            Ok(enc)
+        }
     }
 
     /// Decompress and decrypt chunk, verify MAC.
@@ -137,14 +154,11 @@ impl CryptConfig {
             bail!("Invalid chunk len (<40)");
         }
 
-
         let magic = &data[0..8];
         let iv = &data[8..24];
         let mac = &data[24..40];
 
-        if magic != super::ENCRYPTED_CHUNK_MAGIC_1_0 {
+        if magic == super::ENCR_COMPR_CHUNK_MAGIC_1_0 {
-            bail!("Invalid magic number (expected encrypted chunk).");
-        }
 
             let dec = Vec::with_capacity(1024*1024);
 
@@ -177,6 +191,20 @@ impl CryptConfig {
 
             decompressor.flush()?;
 
-        Ok(decompressor.into_inner())
+            return Ok(decompressor.into_inner());
+
+        } else if magic == super::ENCRYPTED_CHUNK_MAGIC_1_0 {
+            let decr_data = decrypt_aead(
+                self.cipher,
+                &self.enc_key,
+                Some(iv),
+                b"", //??
+                data,
+                mac,
+            )?;
+            return Ok(decr_data);
+        } else {
+            bail!("Invalid magic number (expected encrypted chunk).");
+        }
     }
 }