[PATCH V3] ocfs2: pass u64 to ocfs2_truncate_inline maybe overflow

[Edward Adam Davis]

Syzbot reported a kernel BUG in ocfs2_truncate_inline.
There are two reasons for this: first, the parameter value passed is greater
than UINT_MAX, second, the start and end parameters of ocfs2_truncate_inline
are "unsigned int".

So, we need to add a sanity check for byte_start and byte_len right before
ocfs2_truncate_inline() in ocfs2_remove_inode_range(), if they are greater
than ocfs2_max_inline_data_with_xattr return -EFBIG.

Reported-by: syzbot+81092778aac03460d6b7@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=81092778aac03460d6b7
Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
---
V1 -> V2: move sanity check to ocfs2_remove_inode_range
V2 -> V3: use ocfs2_max_inline_data_with_xattr return value replace UINT_MAX

 fs/ocfs2/file.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c
index ad131a2fc58e..9327aa2f1bf4 100644
--- a/fs/ocfs2/file.c
+++ b/fs/ocfs2/file.c
@@ -1784,6 +1784,12 @@ int ocfs2_remove_inode_range(struct inode *inode,
 		return 0;
 
 	if (OCFS2_I(inode)->ip_dyn_features & OCFS2_INLINE_DATA_FL) {
+		int max_inl = ocfs2_max_inline_data_with_xattr(inode->i_sb, di);
+		if (byte_start > max_inl || byte_start + byte_len > max_inl) {
+			ret = -EFBIG;
+			mlog_errno(ret);
+			goto out;
+		}
 		ret = ocfs2_truncate_inline(inode, di_bh, byte_start,
 					    byte_start + byte_len, 0);
 		if (ret) {
-- 
2.43.0