Re: [PATCH v3 00/10] ACPI: APEI: GHES: Collection of fixes for issues reported by sashiko

[Dave Jiang <dave.jiang@intel.com>]

On 7/21/26 4:33 AM, Rafael J. Wysocki (Intel) wrote:
> On Fri, Jul 17, 2026 at 6:16 PM Dave Jiang <dave.jiang@intel.com> wrote:
>>
>> A collection of fixes for pre-existing issues reported by sashiko-bot while
>> reviewing patches.
>>
>> The v1 posting fixed a first batch of these issues, and v2 grew the set as
>> sashiko-bot's review surfaced more problems in the same CPER/extlog paths.
>> sashiko-bot's review of v2 flagged yet more of the same class of bug in
>> neighbouring code, so v3 adds those as well: an out-of-range section length
>> that defeats cper_estatus_check(), the same unvalidated AER buffer handling
>> in ghes_handle_aer() that was already fixed for extlog, and an unbounded
>> walk of the extlog record.
>>
>> 1/10:  Bound the CXL event record copy to the firmware section length.
>> 2/10:  Reject CPER records with an out-of-range error_data_length.
>> 3/10:  Validate the CXL protocol error section length before the RAS cap copy.
>> 4/10:  Avoid populating software AER metadata from the raw hardware buffer.
>> 5/10:  Validate the PCIe error section length before payload access.
>> 6/10:  Fix the CONFIG_ACPI_APEI_PCIEAER guard typo in extlog.c.
>> 7/10:  Defer CXL protocol error handling to avoid a lock inversion.
>> 8/10:  Validate the memory error section length before payload access.
>> 9/10:  Bound the AER info copy and sanitize software metadata in ghes.c.
>> 10/10: Validate the extlog record length before walking sections.
>>
>> Note patch 2 touches drivers/firmware/efi/cper.c; it closes the length
>> validation hole at the shared choke point that the per-section guards in the
>> rest of the series rely on.
>>
>> sashiko-bot's review of v2 also flagged a few related issues that are not
>> addressed here because they live in other subsystems.
>>
>>   - cxl_cper_print_prot_err() in drivers/firmware/efi/cper_cxl.c uses the
>>     firmware-controlled dvsec_len without bounding it against the section
>>     length.
>>   - cxl_rch_get_aer_info() in drivers/cxl/core/ras_rch.c reads the RCH AER
>>     capability from MMIO into a struct aer_capability_regs without clearing
>>     the software-only header_len/flit fields, the same class of issue as
>>     patches 4 and 9.
>>
>> v1: https://lore.kernel.org/linux-cxl/20260709162807.1957783-1-dave.jiang@intel.com/
>> v2: https://lore.kernel.org/linux-cxl/20260714231835.303081-1-dave.jiang@intel.com/
>>
>> Changes since v2
>> ----------------
>> - Dropped the standalone spin_lock_irqsave() change; it is a separate issue
>>   being handled by Terry Bowman.
>> - New patch 2: reject a section whose error_data_length is out of range in
>>   cper_estatus_check(), closing the signed-int overflow that let a crafted
>>   section bypass the check and defeat the per-caller size guards (sashiko).
>> - New patch 9: apply the same AER buffer sanitization to ghes_handle_aer()
>>   that patch 4 applies to extlog (sashiko).
>> - New patch 10: bound the extlog record and run cper_estatus_check() before
>>   walking its sections, which extlog did not do (sashiko).
>> - Patch 8: move the memory error length check into ghes_do_proc() so the
>>   report chain and arch reporter are covered too, and bound against the
>>   older UEFI 2.1/2.2 layout rather than the full struct (sashiko).
>> - Reordered so the extlog PCIe path is hardened, and the CXL protocol error
>>   handling is deferred to the workqueue, before the typo fix that activates
>>   that code.
>>
>> Changes since v1
>> ----------------
>> - See the v2 posting for the full v1 -> v2 changelog.
>>
>>
>> Dave Jiang (10):
>>   ACPI: APEI: GHES: Bound CXL event record copy to the firmware section
>>     length
>>   efi/cper: Reject CPER records with an out-of-range error_data_length
>>   ACPI: APEI: GHES: Validate CXL protocol error section length before
>>     RAS cap copy
>>   ACPI: extlog: Avoid populating software AER metadata from raw hardware
>>     buffer
>>   ACPI: extlog: Validate PCIe error section length before payload access
>>   ACPI: extlog: Defer CXL protocol error handling to avoid lock
>>     inversion
>>   ACPI: extlog: Fix CONFIG_ACPI_APEI_PCIEAER guard typo
>>   ACPI: APEI: GHES: Validate memory error section length before payload
>>     access
>>   ACPI: APEI: GHES: Bound AER info copy and sanitize software metadata
>>   ACPI: extlog: Validate elog record length before walking sections
>>
>>  drivers/acpi/acpi_extlog.c       | 47 ++++++++++++-------------
>>  drivers/acpi/apei/ghes.c         | 59 +++++++++++++++++++++++++-------
>>  drivers/acpi/apei/ghes_helpers.c | 21 +++++++++++-
>>  drivers/firmware/efi/cper.c      | 10 ++++++
>>  include/acpi/ghes.h              |  4 +++
>>  include/cxl/event.h              |  4 +--
>>  6 files changed, 106 insertions(+), 39 deletions(-)
> 
> All of this looks reasonable to me, but it really is material for Tony
> to look at.

Thanks Rafael. I've asked Tony to take a look. Looks like he's on vacation so hopefully soon.