From: Jan Kara <jack@suse.cz>
Date: Wed, 25 Jan 2023 10:43:03 +0000 (+0100)
Subject: udf: Fix directory iteration for longer tail extents
X-Git-Tag: v6.1.122~6
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6c450489f9c86cc9bde7d39d941c5ae6d05051e8;p=thirdparty%2Fkernel%2Fstable.git

udf: Fix directory iteration for longer tail extents

commit 1ea1cd11c72d1405a6b98440a9d5ea82dfa07166 upstream.

When directory's last extent has more that one block and its length is
not multiple of a block side, the code wrongly decided to move to the
next extent instead of processing the last partial block. This led to
directory corruption. Fix the rounding issue.

Signed-off-by: Jan Kara <jack@suse.cz>
Cc: Shreenidhi Shedi <yesshedi@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/fs/udf/directory.c b/fs/udf/directory.c
index 04169e428fdfa..76dd2e35e0981 100644
--- a/fs/udf/directory.c
+++ b/fs/udf/directory.c
@@ -170,7 +170,7 @@ static struct buffer_head *udf_fiiter_bread_blk(struct udf_fileident_iter *iter)
 static int udf_fiiter_advance_blk(struct udf_fileident_iter *iter)
 {
 	iter->loffset++;
-	if (iter->loffset < iter->elen >> iter->dir->i_blkbits)
+	if (iter->loffset < DIV_ROUND_UP(iter->elen, 1<<iter->dir->i_blkbits))
 		return 0;
 
 	iter->loffset = 0;