>From 1657db149c4c596cf1b2451b73f72db94b612800 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 17 Jun 2024 12:57:50 +0200 Subject: [PATCH] udf: Fix bogus checksum computation in udf_rename() Syzbot reports uninitialized memory access in udf_rename() when updating checksum of '..' directory entry of a moved directory. This is indeed true as we pass on-stack diriter.fi to the udf_update_tag() and because that has only struct fileIdentDesc included in it and not the impUse or name fields, the checksumming function is going to checksum random stack contents beyond the end of the structure. This is actually harmless because the following udf_fiiter_write_fi() will recompute the checksum from on-disk buffers where everything is properly included. So all that is needed is just removing the bogus calculation. Fixes: e9109a92d2a9 ("udf: Convert udf_rename() to new directory iteration code") Link: https://lore.kernel.org/all/000000000000cf405f060d8f75a9@google.com/T/ Reported-by: syzbot+d31185aa54170f7fc1f5@syzkaller.appspotmail.com Signed-off-by: Jan Kara --- fs/udf/namei.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/fs/udf/namei.c b/fs/udf/namei.c index 1308109fd42d..78a603129dd5 100644 --- a/fs/udf/namei.c +++ b/fs/udf/namei.c @@ -876,8 +876,6 @@ static int udf_rename(struct mnt_idmap *idmap, struct inode *old_dir, if (has_diriter) { diriter.fi.icb.extLocation = cpu_to_lelb(UDF_I(new_dir)->i_location); - udf_update_tag((char *)&diriter.fi, - udf_dir_entry_len(&diriter.fi)); udf_fiiter_write_fi(&diriter, NULL); udf_fiiter_release(&diriter); } -- 2.35.3