From b82f50ac7445b690c736ecb42f41d24a3ddc3ba1 Mon Sep 17 00:00:00 2001
From: Colin Finck <colin@reactos.org>
Date: Wed, 25 Aug 2021 16:35:58 +0200
Subject: Validate signatures before record fixup to catch invalid positions
 early

---
 src/file.rs         | 8 ++++----
 src/index_record.rs | 8 ++++----
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/file.rs b/src/file.rs
index 9307f87..16f791c 100644
--- a/src/file.rs
+++ b/src/file.rs
@@ -68,10 +68,10 @@ impl<'n> NtfsFile<'n> {
         fs.read_exact(&mut data)?;
 
         let mut record = Record::new(ntfs, data, position);
+        Self::validate_signature(&record)?;
         record.fixup()?;
 
         let file = Self { record };
-        file.validate_signature()?;
         file.validate_sizes()?;
 
         Ok(file)
@@ -243,15 +243,15 @@ impl<'n> NtfsFile<'n> {
         LittleEndian::read_u32(&self.record.data()[start..])
     }
 
-    fn validate_signature(&self) -> Result<()> {
-        let signature = &self.record.signature();
+    fn validate_signature(record: &Record) -> Result<()> {
+        let signature = &record.signature();
         let expected = b"FILE";
 
         if signature == expected {
             Ok(())
         } else {
             Err(NtfsError::InvalidFileSignature {
-                position: self.record.position(),
+                position: record.position(),
                 expected,
                 actual: *signature,
             })
diff --git a/src/index_record.rs b/src/index_record.rs
index e0fab4f..ddec81a 100644
--- a/src/index_record.rs
+++ b/src/index_record.rs
@@ -58,10 +58,10 @@ impl<'n> NtfsIndexRecord<'n> {
         value.read_exact(fs, &mut data)?;
 
         let mut record = Record::new(value.ntfs(), data, data_position);
+        Self::validate_signature(&record)?;
         record.fixup()?;
 
         let index_record = Self { record };
-        index_record.validate_signature()?;
         index_record.validate_sizes()?;
 
         Ok(index_record)
@@ -116,15 +116,15 @@ impl<'n> NtfsIndexRecord<'n> {
         IndexNodeEntryRanges::new(self.record.into_data(), entries_range, position)
     }
 
-    fn validate_signature(&self) -> Result<()> {
-        let signature = &self.record.signature();
+    fn validate_signature(record: &Record) -> Result<()> {
+        let signature = &record.signature();
         let expected = b"INDX";
 
         if signature == expected {
             Ok(())
         } else {
             Err(NtfsError::InvalidIndexSignature {
-                position: self.record.position(),
+                position: record.position(),
                 expected,
                 actual: *signature,
             })
-- 
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