Re: [PATCH v3 01/10] ACPI: APEI: GHES: Bound CXL event record copy to the firmware section length

On 7/18/26 12:16 AM, Dave Jiang wrote:
> sashiko-bot flagged a missing bounds check that allows an
> out-of-bounds read of the firmware CPER section.
> 
> cxl_cper_post_event() copies a fixed sizeof(struct cxl_cper_event_rec)
> out of the firmware CPER section without checking its length. Pass
> gdata->error_data_length in and reject a section too small to hold the
> record before the copy.
> 
> Reported-by: [email protected]
> Link: https://sashiko.dev/#/patchset/20260617-topics-ahmtib01-ras_ffh_arm_internal_review-v6-0-91f725174aa0@arm.com?part=6
> Fixes: 5e4a264bf8b5 ("acpi/ghes: Process CXL Component Events")
> Assisted-by: Claude:claude-opus-4-8
> Signed-off-by: Dave Jiang <[email protected]>
> ---
>   drivers/acpi/apei/ghes.c | 16 ++++++++++++----
>   1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
> index 3236a3ce79d6..a752e152a5a0 100644
> --- a/drivers/acpi/apei/ghes.c
> +++ b/drivers/acpi/apei/ghes.c
> @@ -815,10 +815,15 @@ static DEFINE_SPINLOCK(cxl_cper_work_lock);
>   struct work_struct *cxl_cper_work;
>   
>   static void cxl_cper_post_event(enum cxl_event_type event_type,
> -				struct cxl_cper_event_rec *rec)
> +				struct cxl_cper_event_rec *rec, u32 len)
>   {
>   	struct cxl_cper_work_data wd;
>   
> +	if (len < sizeof(*rec)) {
> +		pr_err(FW_WARN "CXL CPER section too small (%u)\n", len);
> +		return;
> +	}
> +
>   	if (rec->hdr.length <= sizeof(rec->hdr) ||
>   	    rec->hdr.length > sizeof(*rec)) {
>   		pr_err(FW_WARN "CXL CPER Invalid section length (%u)\n",
> @@ -949,15 +954,18 @@ static void ghes_do_proc(struct ghes *ghes,
>   		} else if (guid_equal(sec_type, &CPER_SEC_CXL_GEN_MEDIA_GUID)) {
>   			struct cxl_cper_event_rec *rec = acpi_hest_get_payload(gdata);
>   
> -			cxl_cper_post_event(CXL_CPER_EVENT_GEN_MEDIA, rec);
> +			cxl_cper_post_event(CXL_CPER_EVENT_GEN_MEDIA, rec,
> +					    gdata->error_data_length);
>   		} else if (guid_equal(sec_type, &CPER_SEC_CXL_DRAM_GUID)) {
>   			struct cxl_cper_event_rec *rec = acpi_hest_get_payload(gdata);
>   
> -			cxl_cper_post_event(CXL_CPER_EVENT_DRAM, rec);
> +			cxl_cper_post_event(CXL_CPER_EVENT_DRAM, rec,
> +					    gdata->error_data_length);
>   		} else if (guid_equal(sec_type, &CPER_SEC_CXL_MEM_MODULE_GUID)) {
>   			struct cxl_cper_event_rec *rec = acpi_hest_get_payload(gdata);
>   
> -			cxl_cper_post_event(CXL_CPER_EVENT_MEM_MODULE, rec);
> +			cxl_cper_post_event(CXL_CPER_EVENT_MEM_MODULE, rec,
> +					    gdata->error_data_length);
>   		} else {
>   			void *err = acpi_hest_get_payload(gdata);
>   


Reviewed-by: Shuai Xue <[email protected]>

Thanks.
Shuai