From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D7C1C1FDA for ; Tue, 23 Jul 2024 01:48:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721699335; cv=none; b=OquTxt+LXJTuv2M9/6s1NcjxqUHa8AmqDKzmQeXilGkJp/PGf3dKOscxilC/B/zqr8TIrIM5zMsetp7h9nOnnlsOW4O6ox0cW2QxvKwmiQ+dd6noxN49SfvwaJ2+rO/VZC/oKLEYCvIaNsvgu6ficL3KY1v1iO4/9oG2NzZLhRI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1721699335; c=relaxed/simple; bh=3D9wf9HZOMAl36iRYLRmC2ZZvwA7HUfg+fd9nltv1Gs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=pZ0JHotQHDBaYOth2wPPehIghJTRYVfh8JY/KMZJi84DnbFSiAtUaT8qiaE2XyBv9FgMXIh7Uv3ZOayMN86Pva11TGZZc1OMz5EJscET7PGzy+1WbaYqspBmW/g0KRP8UyOHfqFAHwIB2QulU+G/XXo3Z8WX+4Nmijarr1RxU9U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=o+RXGdxK; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="o+RXGdxK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5DF2DC116B1; Tue, 23 Jul 2024 01:48:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1721699335; bh=3D9wf9HZOMAl36iRYLRmC2ZZvwA7HUfg+fd9nltv1Gs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=o+RXGdxKG/IYUBu0DTDVtR/tMUAMsUmlHzNyzgm3kKjLBeVFLExt7EaVHn7J5iNO6 OJIM2ITyhHGMsADarR8v7wlrdNG+PFVT3EirXlsbswOOtwGaLqZOgAf7v6hxn9ewMZ 893nL0A6gKATyurhJT/6W+NQaYU3YKTz//T7C6DFjB1vTlc2FbZhQ4U4TNFTjMtzfE t5uTC2vQG/PY1947RENniG5FRQJRuH69+j6s7BIq7iMM6+pVNHj0LnI3UCq0+VFjva gPvJyXVgrdN1xUYMVTLHTe0TyzQBx59bLOMX0DXDHCgBhmqHSXpJapuilQN7jZ/FAV EL7O2SvA6BROw== Date: Tue, 23 Jul 2024 01:48:54 +0000 From: Eric Biggers To: Hannes Reinecke Cc: Christoph Hellwig , Keith Busch , Sagi Grimberg , linux-crypto@vger.kernel.org, linux-nvme@lists.infradead.org Subject: Re: [PATCH 8/9] nvmet-tcp: support secure channel concatenation Message-ID: <20240723014854.GC2319848@google.com> References: <20240722142122.128258-1-hare@kernel.org> <20240722142122.128258-9-hare@kernel.org> Precedence: bulk X-Mailing-List: linux-crypto@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240722142122.128258-9-hare@kernel.org> On Mon, Jul 22, 2024 at 04:21:21PM +0200, Hannes Reinecke wrote: > + ret = nvme_auth_generate_digest(sq->ctrl->shash_id, psk, psk_len, > + sq->ctrl->subsysnqn, > + sq->ctrl->hostnqn, &digest); > + if (ret) { > + pr_warn("%s: ctrl %d qid %d failed to generate digest, error %d\n", > + __func__, sq->ctrl->cntlid, sq->qid, ret); > + goto out_free_psk; > + } > + ret = nvme_auth_derive_tls_psk(sq->ctrl->shash_id, psk, psk_len, > + digest, &tls_psk); > + if (ret) { > + pr_warn("%s: ctrl %d qid %d failed to derive TLS PSK, error %d\n", > + __func__, sq->ctrl->cntlid, sq->qid, ret); > + goto out_free_digest; > + } This reuses 'psk' as both an HMAC key and as input keying material for HKDF. It's *probably* still secure, but this violates cryptographic best practices in that it reuses a key for multiple purposes. Is this a defect in the spec? - Eric