diff rust/hg-core/src/dirstate_tree/dirstate_map.rs @ 47675:48aec076b8fb

dirstate-v2: Enforce data size read from the docket file

The data file may not be shorter than its size given by the docket.
It may be longer, but additional data is ignored.

Differential Revision: https://phab.mercurial-scm.org/D11089

--- a/rust/hg-core/src/dirstate_tree/dirstate_map.rs	Thu Jul 08 12:18:21 2021 +0200
+++ b/rust/hg-core/src/dirstate_tree/dirstate_map.rs	Mon Jul 12 22:46:52 2021 +0200
@@ -410,8 +410,15 @@
     }
 
     #[timed]
-    pub fn new_v2(on_disk: &'on_disk [u8]) -> Result<Self, DirstateError> {
-        Ok(on_disk::read(on_disk)?)
+    pub fn new_v2(
+        on_disk: &'on_disk [u8],
+        data_size: usize,
+    ) -> Result<Self, DirstateError> {
+        if let Some(data) = on_disk.get(..data_size) {
+            Ok(on_disk::read(data)?)
+        } else {
+            Err(DirstateV2ParseError.into())
+        }
     }
 
     #[timed]