Re: [PATCH v4 3/3] btrfs: Use kfree() in btrfs_ioctl_get_subvol_info()

[Waiman Long]

On 6/16/20 10:48 AM, David Sterba wrote:
> On Mon, Jun 15, 2020 at 09:57:18PM -0400, Waiman Long wrote:
> > In btrfs_ioctl_get_subvol_info(), there is a classic case where kzalloc()
> > was incorrectly paired with kzfree(). According to David Sterba, there
> > isn't any sensitive information in the subvol_info that needs to be
> > cleared before freeing. So kfree_sensitive() isn't really needed,
> > use kfree() instead.
> >
> > Reported-by: David Sterba <dsterba@xxxxxxx>
> > Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
> > ---
> >   fs/btrfs/ioctl.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
> > index f1dd9e4271e9..e8f7c5f00894 100644
> > --- a/fs/btrfs/ioctl.c
> > +++ b/fs/btrfs/ioctl.c
> > @@ -2692,7 +2692,7 @@ static int btrfs_ioctl_get_subvol_info(struct file *file, void __user *argp)
> >   	btrfs_put_root(root);
> >   out_free:
> >   	btrfs_free_path(path);
> > -	kfree_sensitive(subvol_info);
> > +	kfree(subvol_info);
> I would rather merge a patch doing to kzfree -> kfree instead of doing
> the middle step to switch it to kfree_sensitive. If it would help
> integration of your patchset I can push it to the next rc so there are
> no kzfree left in the btrfs code. Treewide change like that can take
> time so it would be one less problem to care about for you.
Sure, I will move it forward in the patch series.

Thanks,
Longman