[pve-devel] [PATCH proxmox-backup-qemu v2 3/3] fix #2866: invalidate bitmap on crypt_mode change

[Fabian Grünbichler]

signed and plain backups share chunks, so bitmap reusal is okay for
those combinations. switching from encrypted to not encrypted or
vice-versa could have pretty fatal consequences - either referencing
plain-text chunks in 'encrypted' backups, or referencing encrypted
chunks in 'unencrypted' backups without still having the corresponding
keys..

Signed-off-by: Fabian Grünbichler <f.gruenbichler at proxmox.com>
---
 src/backup.rs   |  5 ++++-
 src/commands.rs | 23 +++++++++++++++++++++++
 2 files changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/backup.rs b/src/backup.rs
index dab1da0..9e3d66a 100644
--- a/src/backup.rs
+++ b/src/backup.rs
@@ -203,7 +203,10 @@ impl BackupTask {
         size: u64,
     ) -> bool {
         match self.last_manifest() {
-            Some(ref manifest) => check_last_incremental_csum(manifest.clone(), &device_name, size),
+            Some(ref manifest) => {
+                check_last_incremental_csum(manifest.clone(), &device_name, size)
+                    && check_last_encryption_mode(manifest.clone(), &device_name, self.crypt_mode)
+            },
             None => false,
         }
     }
diff --git a/src/commands.rs b/src/commands.rs
index e2584ab..c59ee1b 100644
--- a/src/commands.rs
+++ b/src/commands.rs
@@ -94,6 +94,29 @@ pub(crate) fn check_last_incremental_csum(
     }
 }
 
+pub(crate) fn check_last_encryption_mode(
+    manifest: Arc<BackupManifest>,
+    device_name: &str,
+    crypt_mode: CryptMode,
+) -> bool {
+    match manifest.lookup_file_info(&archive_name(device_name)) {
+        Ok(file) => {
+            match file.crypt_mode {
+                CryptMode::Encrypt => match crypt_mode {
+                    CryptMode::Encrypt => true,
+                    _ => false,
+                },
+                CryptMode::SignOnly | CryptMode::None => match crypt_mode {
+                    CryptMode::Encrypt => false,
+                    _ => true,
+                },
+            }
+        },
+        _ => false,
+    }
+}
+
+
 pub(crate) async fn register_image(
     client: Arc<BackupWriter>,
     crypt_config: Option<Arc<CryptConfig>>,
-- 
2.20.1