From 4cbfc805801d8d3e2bcadc563d8416a3c4d79411 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 17 Jun 2024 17:41:51 +0200 Subject: [PATCH] udf: Fix bogus checksum computation in udf_rename() BugLink: https://bugs.launchpad.net/bugs/2083196 [ Upstream commit 27ab33854873e6fb958cb074681a0107cc2ecc4c ] 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/ Link: https://patch.msgid.link/20240617154201.29512-1-jack@suse.cz Reported-by: syzbot+d31185aa54170f7fc1f5@syzkaller.appspotmail.com Signed-off-by: Jan Kara Signed-off-by: Sasha Levin Signed-off-by: Portia Stephens Signed-off-by: Roxana Nicolescu --- fs/udf/namei.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/fs/udf/namei.c b/fs/udf/namei.c index 1bb6ed948927..be48423826f6 100644 --- a/fs/udf/namei.c +++ b/fs/udf/namei.c @@ -873,8 +873,6 @@ 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); }