We assume that modification of some special application could result in zeroed
name_len, or it is consciously made by somebody. We will deadloop in
find_in_block when name_len of dir entry is zero.
This patch is added for preventing deadloop in above scenario.
Signed-off-by: Chao Yu <chao2.yu@xxxxxxxxxxx>
---
fs/f2fs/dir.c | 10 ++++++++++
1 file changed, 10 insertions(+)
diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c
index be8c7af..4316ec5 100644
--- a/fs/f2fs/dir.c
+++ b/fs/f2fs/dir.c
@@ -121,6 +121,16 @@ static struct f2fs_dir_entry *find_in_block(struct page *dentry_page,
}
}
+ /* check name_len to prevent from deadloop here */
+ if (unlikely(de->name_len == 0)) {
+ struct inode *inode = dentry_page->mapping->host;
+
+ f2fs_msg(inode->i_sb, KERN_ERR,
+ "zero-length dir entry, ino = %lu, name = %s",
+ (unsigned long)inode->i_ino, name->name);
+ break;
+ }
+
bit_start = bit_pos
+ GET_DENTRY_SLOTS(le16_to_cpu(de->name_len));
}
--
1.7.9.5
--
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