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Mon, 26 Jan 2026 21:04:04 GMT Received: from smtpav04.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id BC05D58052; Mon, 26 Jan 2026 21:04:04 +0000 (GMT) Received: from smtpav04.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id F0B6458056; Mon, 26 Jan 2026 21:04:03 +0000 (GMT) Received: from li-43857255-d5e6-4659-90f1-fc5cee4750ad.ibm.com (unknown [9.61.66.96]) by smtpav04.dal12v.mail.ibm.com (Postfix) with ESMTP; Mon, 26 Jan 2026 21:04:03 +0000 (GMT) Message-ID: <821cb2becf70b2dcb903e74685643f8b60a5cbb6.camel@linux.ibm.com> Subject: Re: IMA and PQC From: Mimi Zohar To: David Howells Cc: Simo Sorce , Roberto Sassu , Dmitry Kasatkin , Eric Snowberg , Eric Biggers , linux-integrity@vger.kernel.org, linux-crypto@vger.kernel.org, keyrings@vger.kernel.org, linux-modules@vger.kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <1783975.1769190197@warthog.procyon.org.uk> References: <1783975.1769190197@warthog.procyon.org.uk> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Date: Mon, 26 Jan 2026 16:04:03 -0500 Precedence: bulk X-Mailing-List: linux-modules@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Evolution 3.56.2 (3.56.2-2.fc42) X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=Z4vh3XRA c=1 sm=1 tr=0 ts=6977d6c6 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=IkcTkHD0fZMA:10 a=vUbySO9Y5rIA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VwQbUJbxAAAA:8 a=VAaF4WOGAAAA:8 a=e7iQgRXja1ti6KWjARAA:9 a=QEXdDO2ut3YA:10 a=1LTzQqO7nuyEnyYsu_Ii:22 X-Proofpoint-GUID: C7c2I5_y-UyvzjPNTmdcd-tHbdy8bo-y X-Proofpoint-ORIG-GUID: nSKvgNSZHLbx1PiW4tQWlxK8-FdQz7EI X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMTI2MDE3OCBTYWx0ZWRfXzYKehUKHoTKT LHv8w/limEVGmbyTwdEE6ux8HjR37QzxSCoySxzM9O8HAIpIKojrp+/9tbcFnXJ6kyvk/zRYtOq VSsDyNsS/kyuoaj0BbmobYqh/uK2ueCn/wFHb3Z4lBeSlWlnAJMWV9nb9LPPvLH0NGeRhtwltRU pZfwQXKXHKlOnkCxUJbmYRL0XjAdRM6BIYJmkRP0IiEZiWvstWEygmJbYxxvtoif5Dr6ArOAIQM bk6HmkTqiELqVZKwVLjWmXdYhVsecQKqeWS5Lu4Mjt/9AEC+Ygswm09B23FP7KrPSsUbT4/5xEZ YiYyg/huUVBIGnj91lMayXBl9SXUtyvSjIEFzuvzPVFhMubOSKyL4R7Z0HhhcyomcQl6mdB6UVQ cpPMJj3B7+EXSAzbpTAGpOscxtrV++oMhqWY4wJhnIRD2zeLD/GsPW6jfj2QcRn0ymhh/45Y2a2 8MxH2+AT2VW4RHKx7Hg== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.20,FMLib:17.12.100.49 definitions=2026-01-26_04,2026-01-26_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 malwarescore=0 phishscore=0 priorityscore=1501 bulkscore=0 adultscore=0 clxscore=1011 lowpriorityscore=0 impostorscore=0 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2601150000 definitions=main-2601260178 On Fri, 2026-01-23 at 17:43 +0000, David Howells wrote: > Hi Mimi, >=20 > I've posted patches which I hope will accepted to implement ML-DSA module > signing: >=20 > https://lore.kernel.org/linux-crypto/1753972.1769166821@warthog.procyon.= org.uk/T/#t >=20 > but for the moment, it will give an error to pkcs7_get_digest() if there'= s no > digest available (which there won't be with ML-DSA). This means that the= re > isn't a hash for IMA to get at for TPM measurement. IMA calculates the file hash for three different purposes: augment the audi= t log, extend the TPM, and of course verify the file data signature. >From what I gather there is ML-DSA pure and pre-hash modes. What you've implemented is ML-DSA pure mode which passes the data in order to calculate= the file hash, not ML-DSA pre-hash. For this reason, there is no option to use= the file hash. >=20 > Now, I probably have to make a SHA256 hash anyway for UEFI blacklisting > purposes, so that could be used. Alternatively, we can require the use o= f > authenticatedAttributes/signedAttrs and give you the hash of that - but t= hen > you're a bit at the mercy of whatever hashes were used. Let's discuss alternatives and not jump to the conclusion that you have to = break IMA. >=20 > Further, we need to think how we're going to do PQC support in IMA - > particularly as the signatures are so much bigger and verification slower= . Perhaps, but these same reasons would apply to kernel modules, firmware, an= d the kernel image. Why would IMA be special?! >=20 > Would ML-DSA-44 be acceptable? Should we grab some internal state out of > ML-DSA to use in lieu of a hash? Is ML-DSA-44 acceptable for kernel modules, firmware, or the kernel image? Mimi