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From: Eric Biggers <ebiggers@kernel.org>
To: Alexander Larsson <alexl@redhat.com>
Cc: miklos@szeredi.hu, linux-unionfs@vger.kernel.org,
	amir73il@gmail.com, tytso@mit.edu, fsverity@lists.linux.dev
Subject: Re: [PATCH 5/6] ovl: Validate verity xattr when resolving lowerdata
Date: Wed, 26 Apr 2023 14:47:43 -0700	[thread overview]
Message-ID: <20230426214743.GA58528@sol.localdomain> (raw)
In-Reply-To: <df41e9dc96ddad9f9e1e684e39c28f4e097e9d9b.1681917551.git.alexl@redhat.com>

On Thu, Apr 20, 2023 at 09:44:04AM +0200, Alexander Larsson wrote:
> +	err = fsverity_get_digest(d_inode(datapath->dentry), actual_digest, &verity_algo);
> +	if (err < 0) {
> +		pr_warn_ratelimited("lower file '%pd' has no fs-verity digest\n", datapath->dentry);
> +		return -EIO;
> +	}
> +
> +	if (digest_len != hash_digest_size[verity_algo] ||
> +	    memcmp(required_digest, actual_digest, digest_len) != 0) {
> +		pr_warn_ratelimited("lower file '%pd' has the wrong fs-verity digest\n",
> +				    datapath->dentry);
> +		return -EIO;
> +	}
> +
> +	return 0;

This is incorrect because the digest algorithm is not being compared.

- Eric

  parent reply	other threads:[~2023-04-26 21:47 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-04-20  7:43 [PATCH 0/6] ovl: Add support for fs-verity checking of lowerdata Alexander Larsson
2023-04-20  7:44 ` [PATCH 1/6] fsverity: Export fsverity_get_digest Alexander Larsson
2023-04-20  7:44 ` [PATCH 2/6] ovl: Break out ovl_entry_path_real() from ovl_i_path_real() Alexander Larsson
2023-04-20 12:12   ` Amir Goldstein
2023-04-20  7:44 ` [PATCH 3/6] ovl: Break out ovl_entry_path_lowerdata() from ovl_path_lowerdata() Alexander Larsson
2023-04-20 12:14   ` Amir Goldstein
2023-04-20  7:44 ` [PATCH 4/6] ovl: Add framework for verity support Alexander Larsson
2023-04-20  8:39   ` Amir Goldstein
2023-04-25 11:19   ` Miklos Szeredi
2023-04-25 13:33     ` Alexander Larsson
2023-04-25 19:07       ` Miklos Szeredi
2023-04-20  7:44 ` [PATCH 5/6] ovl: Validate verity xattr when resolving lowerdata Alexander Larsson
2023-04-20 12:06   ` Amir Goldstein
2023-04-27  7:33     ` Alexander Larsson
2023-04-26 21:47   ` Eric Biggers [this message]
2023-04-27  7:22     ` Alexander Larsson
2023-04-27 17:58       ` Eric Biggers
2023-04-20  7:44 ` [PATCH 6/6] ovl: Handle verity during copy-up Alexander Larsson
2023-04-20 12:17   ` Amir Goldstein

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