Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > linux.kernel > #1628447

Re: [PATCH 3/5] KEYS: encrypted: sanitize all key material

Show all headers | View raw

On Fri, Apr 21, 2017 at 03:31:08PM +0100, David Howells wrote:
> Eric Biggers <ebiggers3@gmail.com> wrote:
> 
> > -	memzero_explicit(epayload->decrypted_data, epayload->decrypted_datalen);
> > -	kfree(key->payload.data[0]);
> > +	kzfree(key->payload.data[0]);
> 
> Should kzfree() be using memzero_explicit() rather than memset()?
> 
> David

It's not actually needed because it's impossible for the compiler to optimize
away the memset().  memzero_explicit() is only needed on stack data.

The reason I still used memzero_explicit() for heap data in a couple of my
patches, even though it's unnecessary, is just that it makes it clearer that
it's being done for sanitization purposes, as opposed to some random memset.

That's not as much of an issue for kzfree(), since it's explicitly for
sanitization purposes already.

As a separate note, something that might make sense at some point would be to
skip the memset in kzfree() if slab poisoning is enabled.

Eric

Back to linux.kernel | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

[PATCH 3/5] KEYS: encrypted: sanitize all key material Eric Biggers <ebiggers3@gmail.com> - 2017-04-21 10:40 +0200
  Re: [PATCH 3/5] KEYS: encrypted: sanitize all key material David Howells <dhowells@redhat.com> - 2017-04-21 16:40 +0200
    Re: [PATCH 3/5] KEYS: encrypted: sanitize all key material Eric Biggers <ebiggers3@gmail.com> - 2017-04-21 20:30 +0200
      Re: [PATCH 3/5] KEYS: encrypted: sanitize all key material David Howells <dhowells@redhat.com> - 2017-04-24 16:20 +0200

csiph-web