Return an error when encountering corrupted lfn entry

MabezDev · Sep 20, 2024 · 636de0f · 636de0f
1 parent 8ca54b6
commit 636de0f
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Showing 2 changed files with 11 additions and 5 deletions.
diff --git a/embedded-fatfs/src/dir.rs b/embedded-fatfs/src/dir.rs
@@ -779,7 +779,7 @@ impl<'a, IO: ReadWriteSeek, TP: TimeProvider, OCC> DirIter<'a, IO, TP, OCC> {
                 DirEntryData::Lfn(data) => {
                     // Append to LFN buffer
                     trace!("lfn entry");
-                    lfn_builder.process(&data);
+                    lfn_builder.process::<IO>(&data)?;
                 }
             }
         }
@@ -1003,14 +1003,14 @@ impl LongNameBuilder {
         self.index == 0
     }
 
-    fn process(&mut self, data: &DirLfnEntryData) {
+    fn process<IO: ReadWriteSeek>(&mut self, data: &DirLfnEntryData) -> Result<(), Error<IO::Error>> {
         let is_last = (data.order() & LFN_ENTRY_LAST_FLAG) != 0;
         let index = data.order() & 0x1F;
         if index == 0 || usize::from(index) > MAX_LONG_DIR_ENTRIES {
             // Corrupted entry
             warn!("corrupted lfn entry! {:x}", data.order());
             self.clear();
-            return;
+            return Err(Error::CorruptedFileEntry);
         }
         if is_last {
             // last entry is actually first entry in stream
@@ -1027,14 +1027,15 @@ impl LongNameBuilder {
                 self.chksum
             );
             self.clear();
-            return;
+            return Err(Error::CorruptedFileEntry);
         } else {
             // Decrement LFN index only for non-last entries
             self.index -= 1;
         }
         let pos = LFN_PART_LEN * usize::from(index - 1);
         // copy name parts into LFN buffer
         data.copy_name_to_slice(&mut self.buf.ucs2_units[pos..pos + 13]);
+        Ok(())
     }
 
     fn validate_chksum(&mut self, short_name: &[u8; SFN_SIZE]) {
@@ -1061,7 +1062,9 @@ impl LongNameBuilder {
     fn clear(&mut self) {}
     fn into_vec(self) {}
     fn truncate(&mut self) {}
-    fn process(&mut self, _data: &DirLfnEntryData) {}
+    fn process<IO: ReadWriteSeek>(&mut self, _data: &DirLfnEntryData) -> Result<(), Error<IO::Error>> {
+        Ok(())
+    }
     fn validate_chksum(&mut self, _short_name: &[u8; SFN_SIZE]) {}
 }
 

diff --git a/embedded-fatfs/src/error.rs b/embedded-fatfs/src/error.rs
@@ -30,6 +30,8 @@ pub enum Error<T> {
     InvalidFileNameLength,
     /// The provided file name contains an invalid character.
     UnsupportedFileNameCharacter,
+    /// An entry in the file table is corrupted/invalid.
+    CorruptedFileEntry,
 }
 
 impl<T: Debug> IoError for Error<T> {
@@ -76,6 +78,7 @@ impl<T: core::fmt::Display> core::fmt::Display for Error<T> {
             Error::NotFound => write!(f, "No such file or directory"),
             Error::AlreadyExists => write!(f, "File or directory already exists"),
             Error::CorruptedFileSystem => write!(f, "Corrupted file system"),
+            Error::CorruptedFileEntry => write!(f, "Corrupted file entry"),
         }
     }
 }