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From:   Bragatheswaran Manickavel <bragathemanick0908@gmail.com>
To:     reiserfs-devel@vger.kernel.org
Cc:     Bragatheswaran Manickavel <bragathemanick0908@gmail.com>,
        linux-kernel@vger.kernel.org,
        syzbot+e5bb9eb00a5a5ed2a9a2@syzkaller.appspotmail.com
Subject: [PATCH] reiserfs: UBSAN: array-index-out-of-bounds in direntry_create_vi
Date:   Thu, 26 Oct 2023 18:26:16 +0530
Message-Id: <20231026125616.1859-1-bragathemanick0908@gmail.com>
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deh defined as an array of type __u16[], and issue is
triggered when it's trying to access an element at
index 1, which is out of bounds because the array
has only one element at index 0.

Reported-by: syzbot+e5bb9eb00a5a5ed2a9a2@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=e5bb9eb00a5a5ed2a9a2
Signed-off-by: Bragatheswaran Manickavel <bragathemanick0908@gmail.com>
---
 fs/reiserfs/item_ops.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/reiserfs/item_ops.c b/fs/reiserfs/item_ops.c
index 3a5a752d96c7..ccf547c5e8e1 100644
--- a/fs/reiserfs/item_ops.c
+++ b/fs/reiserfs/item_ops.c
@@ -484,7 +484,7 @@ static int direntry_create_vi(struct virtual_node *vn,
 				  vn->vn_mode);
 		dir_u->entry_sizes[i] =
 		    (j ? deh_location(&deh[j - 1]) : ih_item_len(vi->vi_ih)) -
-		    deh_location(&deh[j]) + DEH_SIZE;
+		    deh_location(&deh[j - 1]) + DEH_SIZE;
 	}
 
 	size += (dir_u->entry_count * sizeof(short));
-- 
2.34.1