linux/drivers/acpi/apei/bert.c
Ross Lagerwall 1c0d9b1c31 ACPI: APEI: Fix possible out-of-bounds access to BERT region
Check that the length recorded in the generic error status block is
within the region before checking the contents of the region itself.

Otherwise it may result in an out-of-bounds access if the system
firmware has generated a status block with an invalid length (larger
than the mapped region). Also move the block_status check so that it
only happens after the block has been verified to be within the mapped
region.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Acked-by: Borislav Petkov <bp@suse.de>
Tested-by: Tyler Baicar <baicar.tyler@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2019-02-20 10:34:03 +01:00

152 lines
3.7 KiB
C

/*
* APEI Boot Error Record Table (BERT) support
*
* Copyright 2011 Intel Corp.
* Author: Huang Ying <ying.huang@intel.com>
*
* Under normal circumstances, when a hardware error occurs, the error
* handler receives control and processes the error. This gives OSPM a
* chance to process the error condition, report it, and optionally attempt
* recovery. In some cases, the system is unable to process an error.
* For example, system firmware or a management controller may choose to
* reset the system or the system might experience an uncontrolled crash
* or reset.The boot error source is used to report unhandled errors that
* occurred in a previous boot. This mechanism is described in the BERT
* table.
*
* For more information about BERT, please refer to ACPI Specification
* version 4.0, section 17.3.1
*
* This file is licensed under GPLv2.
*
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/acpi.h>
#include <linux/io.h>
#include "apei-internal.h"
#undef pr_fmt
#define pr_fmt(fmt) "BERT: " fmt
static int bert_disable;
static void __init bert_print_all(struct acpi_bert_region *region,
unsigned int region_len)
{
struct acpi_hest_generic_status *estatus =
(struct acpi_hest_generic_status *)region;
int remain = region_len;
u32 estatus_len;
while (remain >= sizeof(struct acpi_bert_region)) {
estatus_len = cper_estatus_len(estatus);
if (remain < estatus_len) {
pr_err(FW_BUG "Truncated status block (length: %u).\n",
estatus_len);
return;
}
/* No more error records. */
if (!estatus->block_status)
return;
if (cper_estatus_check(estatus)) {
pr_err(FW_BUG "Invalid error record.\n");
return;
}
pr_info_once("Error records from previous boot:\n");
cper_estatus_print(KERN_INFO HW_ERR, estatus);
/*
* Because the boot error source is "one-time polled" type,
* clear Block Status of current Generic Error Status Block,
* once it's printed.
*/
estatus->block_status = 0;
estatus = (void *)estatus + estatus_len;
remain -= estatus_len;
}
}
static int __init setup_bert_disable(char *str)
{
bert_disable = 1;
return 0;
}
__setup("bert_disable", setup_bert_disable);
static int __init bert_check_table(struct acpi_table_bert *bert_tab)
{
if (bert_tab->header.length < sizeof(struct acpi_table_bert) ||
bert_tab->region_length < sizeof(struct acpi_bert_region))
return -EINVAL;
return 0;
}
static int __init bert_init(void)
{
struct apei_resources bert_resources;
struct acpi_bert_region *boot_error_region;
struct acpi_table_bert *bert_tab;
unsigned int region_len;
acpi_status status;
int rc = 0;
if (acpi_disabled)
return 0;
if (bert_disable) {
pr_info("Boot Error Record Table support is disabled.\n");
return 0;
}
status = acpi_get_table(ACPI_SIG_BERT, 0, (struct acpi_table_header **)&bert_tab);
if (status == AE_NOT_FOUND)
return 0;
if (ACPI_FAILURE(status)) {
pr_err("get table failed, %s.\n", acpi_format_exception(status));
return -EINVAL;
}
rc = bert_check_table(bert_tab);
if (rc) {
pr_err(FW_BUG "table invalid.\n");
return rc;
}
region_len = bert_tab->region_length;
apei_resources_init(&bert_resources);
rc = apei_resources_add(&bert_resources, bert_tab->address,
region_len, true);
if (rc)
return rc;
rc = apei_resources_request(&bert_resources, "APEI BERT");
if (rc)
goto out_fini;
boot_error_region = ioremap_cache(bert_tab->address, region_len);
if (boot_error_region) {
bert_print_all(boot_error_region, region_len);
iounmap(boot_error_region);
} else {
rc = -ENOMEM;
}
apei_resources_release(&bert_resources);
out_fini:
apei_resources_fini(&bert_resources);
return rc;
}
late_initcall(bert_init);