linux-kernel - Re: [PATCH v1 2/3] virt: tsm: Increase TSM_REPORT_OUTBLOB

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <698be6787e2de_8c321007f@dwillia2-mobl4.notmuch>
Date: Tue, 10 Feb 2026 18:16:24 -0800
From: <dan.j.williams@...el.com>
To: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>,
	Dan Williams <dan.j.williams@...el.com>, "Kirill A . Shutemov"
	<kas@...nel.org>
CC: Dave Hansen <dave.hansen@...ux.intel.com>, Rick Edgecombe
	<rick.p.edgecombe@...el.com>, <x86@...nel.org>,
	<linux-kernel@...r.kernel.org>, <linux-coco@...ts.linux.dev>
Subject: Re: [PATCH v1 2/3] virt: tsm: Increase TSM_REPORT_OUTBLOB_MAX to 16MB

Kuppuswamy Sathyanarayanan wrote:
> Confidential Computing (CoCo) attestation is evolving toward
> standardized models such as DICE (Device Identifier Composition Engine)
> and Post-Quantum Cryptography (PQC), which rely on layered certificate
> chains and larger cryptographic signatures.
> 
> A typical PQC certificate can range from 5KB to 15KB, and DICE-based
> architectures accumulate these certificates across multiple boot
> stages. In such configurations, the total attestation evidence can
> reach several megabytes, exceeding the current 32KB limit.
> 
> Increase TSM_REPORT_OUTBLOB_MAX to 16MB to accommodate these larger
> certificate chains. This provides sufficient headroom to handle
> evolving requirements without requiring frequent updates to the limit.
> 
> TSM_REPORT_OUTBLOB_MAX is used by the configfs read interface to cap
> the maximum allowed binary blob size for outblob, auxblob and
> manifestblob attributes. Hence, the per-open-file worst case memory
> allocation increases from 32KB to 16MB. Multiple concurrent readers
> multiply this cost (e.g., N readers of an M-byte blob incur NxM bytes
> of vmalloc-backed memory). However, allocations are performed on demand
> and remain proportional to the actual blob length, not the configured
> maximum.

Looks ok, again I will change the subject to:

"configfs-tsm-report: Increase TSM_REPORT_OUTBLOB_MAX to 16MB"