From fa2408a24f8f0db14d9cfc613ef162dc267d7ad4 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Thu, 8 Jan 2026 12:35:05 +0100 Subject: [PATCH] APEI/GHES: ensure that won't go past CPER allocated record The logic at ghes_new() prevents allocating too large records, by checking if they're bigger than GHES_ESTATUS_MAX_SIZE (currently, 64KB). Yet, the allocation is done with the actual number of pages from the CPER bios table location, which can be smaller. Yet, a bad firmware could send data with a different size, which might be bigger than the allocated memory, causing an OOPS: Unable to handle kernel paging request at virtual address fff00000f9b40000 Mem abort info: ESR = 0x0000000096000007 EC = 0x25: DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 FSC = 0x07: level 3 translation fault Data abort info: ISV = 0, ISS = 0x00000007, ISS2 = 0x00000000 CM = 0, WnR = 0, TnD = 0, TagAccess = 0 GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 swapper pgtable: 4k pages, 52-bit VAs, pgdp=000000008ba16000 [fff00000f9b40000] pgd=180000013ffff403, p4d=180000013fffe403, pud=180000013f85b403, pmd=180000013f68d403, pte=0000000000000000 Internal error: Oops: 0000000096000007 [#1] SMP Modules linked in: CPU: 0 UID: 0 PID: 303 Comm: kworker/0:1 Not tainted 6.19.0-rc1-00002-gda407d200220 #34 PREEMPT Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 02/02/2022 Workqueue: kacpi_notify acpi_os_execute_deferred pstate: 214020c5 (nzCv daIF +PAN -UAO -TCO +DIT -SSBS BTYPE=--) pc : hex_dump_to_buffer+0x30c/0x4a0 lr : hex_dump_to_buffer+0x328/0x4a0 sp : ffff800080e13880 x29: ffff800080e13880 x28: ffffac9aba86f6a8 x27: 0000000000000083 x26: fff00000f9b3fffc x25: 0000000000000004 x24: 0000000000000004 x23: ffff800080e13905 x22: 0000000000000010 x21: 0000000000000083 x20: 0000000000000001 x19: 0000000000000008 x18: 0000000000000010 x17: 0000000000000001 x16: 00000007c7f20fec x15: 0000000000000020 x14: 0000000000000008 x13: 0000000000081020 x12: 0000000000000008 x11: ffff800080e13905 x10: ffff800080e13988 x9 : 0000000000000000 x8 : 0000000000000000 x7 : 0000000000000001 x6 : 0000000000000020 x5 : 0000000000000030 x4 : 00000000fffffffe x3 : 0000000000000000 x2 : ffffac9aba78c1c8 x1 : ffffac9aba76d0a8 x0 : 0000000000000008 Call trace: hex_dump_to_buffer+0x30c/0x4a0 (P) print_hex_dump+0xac/0x170 cper_estatus_print_section+0x90c/0x968 cper_estatus_print+0xf0/0x158 __ghes_print_estatus+0xa0/0x148 ghes_proc+0x1bc/0x220 ghes_notify_hed+0x5c/0xb8 notifier_call_chain+0x78/0x148 blocking_notifier_call_chain+0x4c/0x80 acpi_hed_notify+0x28/0x40 acpi_ev_notify_dispatch+0x50/0x80 acpi_os_execute_deferred+0x24/0x48 process_one_work+0x15c/0x3b0 worker_thread+0x2d0/0x400 kthread+0x148/0x228 ret_from_fork+0x10/0x20 Code: 6b14033f 540001ad a94707e2 f100029f (b8747b44) ---[ end trace 0000000000000000 ]--- Prevent that by taking the actual allocated are into account when checking for CPER length. Signed-off-by: Mauro Carvalho Chehab Reviewed-by: Jonathan Cameron Acked-by: Ard Biesheuvel Reviewed-by: Hanjun Guo [ rjw: Subject tweaks ] Link: https://patch.msgid.link/4e70310a816577fabf37d94ed36cde4ad62b1e0a.1767871950.git.mchehab+huawei@kernel.org Signed-off-by: Rafael J. Wysocki --- drivers/acpi/apei/ghes.c | 6 +++++- include/acpi/ghes.h | 1 + 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c index fc3f8aed99d5f..77ea7a5b761f1 100644 --- a/drivers/acpi/apei/ghes.c +++ b/drivers/acpi/apei/ghes.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include #include @@ -294,6 +295,7 @@ static struct ghes *ghes_new(struct acpi_hest_generic *generic) error_block_length = GHES_ESTATUS_MAX_SIZE; } ghes->estatus = kmalloc(error_block_length, GFP_KERNEL); + ghes->estatus_length = error_block_length; if (!ghes->estatus) { rc = -ENOMEM; goto err_unmap_status_addr; @@ -365,13 +367,15 @@ static int __ghes_check_estatus(struct ghes *ghes, struct acpi_hest_generic_status *estatus) { u32 len = cper_estatus_len(estatus); + u32 max_len = min(ghes->generic->error_block_length, + ghes->estatus_length); if (len < sizeof(*estatus)) { pr_warn_ratelimited(FW_WARN GHES_PFX "Truncated error status block!\n"); return -EIO; } - if (len > ghes->generic->error_block_length) { + if (!len || len > max_len) { pr_warn_ratelimited(FW_WARN GHES_PFX "Invalid error status block length!\n"); return -EIO; } diff --git a/include/acpi/ghes.h b/include/acpi/ghes.h index ebd21b05fe6ed..93db60da5934e 100644 --- a/include/acpi/ghes.h +++ b/include/acpi/ghes.h @@ -21,6 +21,7 @@ struct ghes { struct acpi_hest_generic_v2 *generic_v2; }; struct acpi_hest_generic_status *estatus; + unsigned int estatus_length; unsigned long flags; union { struct list_head list; -- 2.47.3