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

On Fri, Jul 17, 2026 at 6:16 PM Dave Jiang <[email protected]> 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/[email protected]/
> v2: https://lore.kernel.org/linux-cxl/[email protected]/
>
> 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.