ACPI: APEI: GHES: Validate memory error section length before payload access

ghes_do_proc() hands the CPER_SEC_PLATFORM_MEM payload to the report chain,
arch_apei_report_mem_error() and ghes_handle_memory_failure() without
checking gdata->error_data_length. All three read validation_bits and
physical_addr, at offsets 0 and 16, so a shorter section reads past the
record.

Check the length once in ghes_do_proc(), before any consumer runs. Take the
73-byte struct cper_sec_mem_err_old as the floor: older firmware
legitimately emits that UEFI 2.1/2.2 layout, and it makes validation_bits
safe to read.

The fields from "extended" on are absent from that layout, so also require
whatever length the validation bits claim. Derive it per field rather than
demanding the full 80 bytes: rank needs only 76, and the BANK_GROUP and
BANK_ADDRESS bits describe "bank" at offset 38, which every record carries.
Testing the whole mask against one size, as cper_print_mem() does, gets it
wrong both ways.

Reported-by: sashiko-bot@kernel.org
Closes: https://sashiko.dev/#/patchset/20260714231835.303081-1-dave.jiang@intel.com?part=7
Fixes: ca104edc1784 ("ACPI, APEI, GHES: Cleanup ghes memory error handling")
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Reviewed-by: Shuai Xue <xueshuai@linux.alibaba.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/20260904172337.1409775-12-dave.jiang@intel.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

0 files changed, 0 insertions, 0 deletions