From: Jan Kara jack@suse.cz
[ 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 jack@suse.cz Signed-off-by: Thadeu Lima de Souza Cascardo cascardo@igalia.com --- fs/udf/namei.c | 2 -- 1 file changed, 2 deletions(-)
diff --git a/fs/udf/namei.c b/fs/udf/namei.c index 093de955ba10..5e39cbc74524 100644 --- a/fs/udf/namei.c +++ b/fs/udf/namei.c @@ -857,8 +857,6 @@ static int udf_rename(struct user_namespace *mnt_userns, 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);