[PATCH 6.18 053/752] APEI/GHES: ARM processor Error: don't go past allocated memory

Sasha Levin
2026-02-28T17:48:53Z

From: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

[ Upstream commit 87880af2d24e62a84ed19943dbdd524f097172f2 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/acpi/apei/ghes.c | 32 ++++++++++++++++++++++++++++----
drivers/ras/ras.c | 6 +++++-
2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/drivers/acpi/apei/ghes.c b/drivers/acpi/apei/ghes.c
index 1b34a708e98a4..42872fdc36bfc 100644
--- a/drivers/acpi/apei/ghes.c
+++ b/drivers/acpi/apei/ghes.c
@@ -561,21 +561,45 @@ 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
diff --git a/drivers/ras/ras.c b/drivers/ras/ras.c
index 2a5b5a9fdcb36..03df3db623346 100644
--- a/drivers/ras/ras.c
+++ b/drivers/ras/ras.c
@@ -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;
}
--
2.51.0