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APEI/GHES: ARM processor Error: don't go past allocated memory

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If the BIOS generates a very small ARM Processor Error, or
an incomplete one, the current logic will fail to deferrence

	err->section_length
and
	ctx_info->size

Add checks to avoid that. With such changes, such GHESv2
records won't cause OOPSes like this:

[    1.492129] Internal error: Oops: 0000000096000005 [#1]  SMP
[    1.495449] Modules linked in:
[    1.495820] CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted 6.18.0-rc1-00017-gabadcc3553dd-dirty #18 PREEMPT
[    1.496125] Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 02/02/2022
[    1.496433] Workqueue: kacpi_notify acpi_os_execute_deferred
[    1.496967] pstate: 814000c5 (Nzcv daIF +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[    1.497199] pc : log_arm_hw_error+0x5c/0x200
[    1.497380] lr : ghes_handle_arm_hw_error+0x94/0x220

0xffff8000811c5324 is in log_arm_hw_error (../drivers/ras/ras.c:75).
70		err_info = (struct cper_arm_err_info *)(err + 1);
71		ctx_info = (struct cper_arm_ctx_info *)(err_info + err->err_info_num);
72		ctx_err = (u8 *)ctx_info;
73
74		for (n = 0; n < err->context_info_num; n++) {
75			sz = sizeof(struct cper_arm_ctx_info) + ctx_info->size;
76			ctx_info = (struct cper_arm_ctx_info *)((long)ctx_info + sz);
77			ctx_len += sz;
78		}
79

and similar ones while trying to access section_length on an
error dump with too small size.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
[ rjw: Subject tweaks ]
Link: https://patch.msgid.link/7fd9f38413be05ee2d7cfdb0dc31ea2274cf1a54.1767871950.git.mchehab+huawei@kernel.org
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Mauro Carvalho Chehab 2026-01-08 12:35:03 +01:00 • committed by Rafael J. Wysocki
parent cae444e0e2
commit 87880af2d2
2 changed files with 33 additions and 5 deletions
Download patch file Download diff file Expand all files Collapse all files

32
drivers/acpi/apei/ghes.c
View file

@ -552,21 +552,45 @@ static bool ghes_handle_arm_hw_error(struct acpi_hest_generic_data *gdata,
{
struct cper_sec_proc_arm *err = acpi_hest_get_payload(gdata);
int flags = sync ? MF_ACTION_REQUIRED : 0;
int length = gdata->error_data_length;
char error_type[120];
bool queued = false;
int sec_sev, i;
char *p;
sec_sev = ghes_severity(gdata->error_severity);
log_arm_hw_error(err, sec_sev);
if (length >= sizeof(*err)) {
log_arm_hw_error(err, sec_sev);
} else {
pr_warn(FW_BUG "arm error length: %d\n", length);
pr_warn(FW_BUG "length is too small\n");
pr_warn(FW_BUG "firmware-generated error record is incorrect\n");
return false;
}
if (sev != GHES_SEV_RECOVERABLE || sec_sev != GHES_SEV_RECOVERABLE)
return false;
p = (char *)(err + 1);
length -= sizeof(err);
for (i = 0; i < err->err_info_num; i++) {
struct cper_arm_err_info *err_info = (struct cper_arm_err_info *)p;
bool is_cache = err_info->type & CPER_ARM_CACHE_ERROR;
bool has_pa = (err_info->validation_bits & CPER_ARM_INFO_VALID_PHYSICAL_ADDR);
struct cper_arm_err_info *err_info;
bool is_cache, has_pa;
/* Ensure we have enough data for the error info header */
if (length < sizeof(*err_info))
break;
err_info = (struct cper_arm_err_info *)p;
/* Validate the claimed length before using it */
length -= err_info->length;
if (length < 0)
break;
is_cache = err_info->type & CPER_ARM_CACHE_ERROR;
has_pa = (err_info->validation_bits & CPER_ARM_INFO_VALID_PHYSICAL_ADDR);
/*
* The field (err_info->error_info & BIT(26)) is fixed to set to

6
drivers/ras/ras.c
View file

@ -72,7 +72,11 @@ void log_arm_hw_error(struct cper_sec_proc_arm *err, const u8 sev)
ctx_err = (u8 *)ctx_info;
for (n = 0; n < err->context_info_num; n++) {
sz = sizeof(struct cper_arm_ctx_info) + ctx_info->size;
sz = sizeof(struct cper_arm_ctx_info);
if (sz + (long)ctx_info - (long)err >= err->section_length)
sz += ctx_info->size;
ctx_info = (struct cper_arm_ctx_info *)((long)ctx_info + sz);
ctx_len += sz;
}