Re: [Patch 2.6] dm-crypt: zero key before freeing it

[Stefan Rompf <stefan@loplof.de>]

Am Dienstag 24 Januar 2006 05:49 schrieb Neil Brown:

> >--- linux-2.6.14.4/drivers/md/dm-crypt.c.old	2005-12-16 18:27:05.000000000
> > +0100 +++ linux-2.6.14.4/drivers/md/dm-crypt.c	2005-12-28
> > 12:49:13.000000000 +0100 @@ -694,6 +694,7 @@ bad3:
> > bad2:
> > 	crypto_free_tfm(tfm);
> > bad1:
> >+	memset(cc, 0, sizeof(*cc) + cc->key_size * sizeof(u8));
> > 	kfree(cc);
> > 	return -EINVAL;
> > }
>
> There is a small problem with this patch.
> If the 'goto bad1' branch is taken, then 'cc->key_size' will not be
> defined.
> I think you need the following patch on top.

Why? This is from today's git, just before the first goto bad1

 559         cc->key_size = key_size;
 560         if ((!key_size && strcmp(argv[1], "-") != 0) ||
 561             (key_size && crypt_decode_key(cc->key, argv[1], key_size) < 
0)) {
 562                 ti->error = PFX "Error decoding key";
 563                 goto bad1;
 564         }

Stefan