fs/ntfs3: Fix memory corruption when page_size changes

The rework in fs/ntfs3: Reduce stack usage changes log->page_size but doesn't change the associated log->page_mask and log->page_bits. That results in the bytes value in read_log_page getting a negative value, which is bad when it is passed to memcpy. The kernel panic can be observed when connecting an ntfs formatted drive that has previously been connected to a Windows machine to a Raspberry Pi 5, which by defauilt uses a 16K kernel pagesize. Fixes: 865e7a7 ("fs/ntfs3: Reduce stack usage") Signed-off-by: Dom Cobley <[email protected]>
raspberrypi · Jun 21, 2024 · 7af85d5 · 7af85d5
1 parent 47dce8e
commit 7af85d5
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/fs/ntfs3/fslog.c b/fs/ntfs3/fslog.c
@@ -3907,6 +3907,8 @@ int log_replay(struct ntfs_inode *ni, bool *initialized)
 		log->l_size = log->orig_file_size;
 		log->page_size = norm_file_page(t32, &log->l_size,
 						t32 == DefaultLogPageSize);
+		log->page_mask = log->page_size - 1;
+		log->page_bits = blksize_bits(log->page_size);
 	}
 
 	if (log->page_size != t32 ||