From: Mimi Zohar <zohar@linux.ibm.com>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-integrity@vger.kernel.org, linux-fscrypt@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 4/5] ima: support fs-verity file digest based signatures
Date: Thu, 02 Dec 2021 17:13:15 -0500 [thread overview]
Message-ID: <4dc45d1ec7450b4d1d06b12baf73668525bd8157.camel@linux.ibm.com> (raw)
In-Reply-To: <YalDvGjq0inMFKln@sol.localdomain>
On Thu, 2021-12-02 at 14:07 -0800, Eric Biggers wrote:
> On Thu, Dec 02, 2021 at 04:55:06PM -0500, Mimi Zohar wrote:
> > case IMA_VERITY_DIGSIG:
> > - fallthrough;
> > + set_bit(IMA_DIGSIG, &iint->atomic_flags);
> > +
> > + /*
> > + * The IMA signature is based on a hash of IMA_VERITY_DIGSIG
> > + * and the fs-verity file digest, not directly on the
> > + * fs-verity file digest. Both digests should probably be
> > + * included in the IMA measurement list, but for now this
> > + * digest is only used for verifying the IMA signature.
> > + */
> > + verity_digest[0] = IMA_VERITY_DIGSIG;
> > + memcpy(verity_digest + 1, iint->ima_hash->digest,
> > + iint->ima_hash->length);
> > +
> > + hash.hdr.algo = iint->ima_hash->algo;
> > + hash.hdr.length = iint->ima_hash->length;
>
> This is still wrong because the bytes being signed don't include the hash
> algorithm. Unless you mean for it to be implicitly always SHA-256? fs-verity
> supports SHA-512 too, and it may support other hash algorithms in the future.
The signature stored in security.ima is prefixed with a header
(signature_v2_hdr).
Mimi
next prev parent reply other threads:[~2021-12-02 22:13 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-02 21:55 [PATCH v1 0/5] ima: support fs-verity signatures stored as Mimi Zohar
2021-12-02 21:55 ` [PATCH v1 1/5] fs-verity: define a function to return the integrity protected file digest Mimi Zohar
2021-12-02 22:15 ` Eric Biggers
2021-12-02 21:55 ` [PATCH v1 2/5] ima: define a new signature type named IMA_VERITY_DIGSIG Mimi Zohar
2021-12-02 21:55 ` [PATCH v1 3/5] ima: limit including fs-verity's file digest in measurement list Mimi Zohar
2021-12-02 22:22 ` Eric Biggers
2021-12-02 22:55 ` Mimi Zohar
2021-12-02 21:55 ` [PATCH v1 4/5] ima: support fs-verity file digest based signatures Mimi Zohar
2021-12-02 22:07 ` Eric Biggers
2021-12-02 22:13 ` Mimi Zohar [this message]
2021-12-02 22:18 ` Eric Biggers
2021-12-31 15:35 ` Mimi Zohar
2022-01-05 23:37 ` Eric Biggers
2022-01-09 20:45 ` Vitaly Chikunov
2022-01-09 21:07 ` Eric Biggers
2022-01-15 5:31 ` Vitaly Chikunov
2022-01-15 6:21 ` Eric Biggers
2022-01-16 3:31 ` Stefan Berger
2022-01-16 5:24 ` Stefan Berger
2022-01-19 0:49 ` Eric Biggers
2022-01-19 15:41 ` Stefan Berger
2022-01-16 17:01 ` Mimi Zohar
2022-01-19 0:39 ` Eric Biggers
2022-01-20 16:39 ` Mimi Zohar
2022-01-20 21:05 ` Eric Biggers
2021-12-02 21:55 ` [PATCH v1 5/5] fsverity: update the documentation Mimi Zohar
2021-12-02 22:09 ` Eric Biggers
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