Commit 87880af2 authored by Mauro Carvalho Chehab's avatar Mauro Carvalho Chehab Committed by Rafael J. Wysocki
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APEI/GHES: ARM processor Error: don't go past allocated memory 



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: default avatarMauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: default avatarJonathan Cameron <jonathan.cameron@huawei.com>
Acked-by: default avatarArd Biesheuvel <ardb@kernel.org>
Reviewed-by: default avatarHanjun Guo <guohanjun@huawei.com>
[ rjw: Subject tweaks ]
Link: https://patch.msgid.link/7fd9f38413be05ee2d7cfdb0dc31ea2274cf1a54.1767871950.git.mchehab+huawei@kernel.org


Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent cae444e0

drivers/acpi/apei/ghes.c

+28 −4
Original line number Diff line number Diff line
@@ -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);

	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

drivers/ras/ras.c

+5 −1
Original line number Diff line number Diff line
@@ -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;

	}