diff options
| author | Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> | 2026-02-10 16:17:11 -0800 |
|---|---|---|
| committer | Dan Williams <dan.j.williams@intel.com> | 2026-02-10 18:21:21 -0800 |
| commit | 9342bf3d670b1b3d3cfc77a9dc1cd0d6574e5cc6 (patch) | |
| tree | 4cf69cfa2da82d868b8c4479b06fd06c7926ddcc | |
| parent | 5f486958bfae4e2059a26b947661a60efedd092d (diff) | |
configfs-tsm-report: Increase TSM_REPORT_OUTBLOB_MAX to 16MB
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.
Reviewed-by: Fang Peter <peter.fang@intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Link: https://patch.msgid.link/20260211001712.1531955-3-sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| -rw-r--r-- | include/linux/tsm.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/include/linux/tsm.h b/include/linux/tsm.h index a3b7ab668eff..7f72a154b6b2 100644 --- a/include/linux/tsm.h +++ b/include/linux/tsm.h @@ -8,7 +8,7 @@ #include <linux/device.h> #define TSM_REPORT_INBLOB_MAX 64 -#define TSM_REPORT_OUTBLOB_MAX SZ_32K +#define TSM_REPORT_OUTBLOB_MAX SZ_16M /* * Privilege level is a nested permission concept to allow confidential |