OpenCloudOS-Kernel/security/integrity/platform_certs/load_uefi.c

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// SPDX-License-Identifier: GPL-2.0
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/cred.h>
efi: Do not import certificates from UEFI Secure Boot for T2 Macs On Apple T2 Macs, when Linux attempts to read the db and dbx efi variables at early boot to load UEFI Secure Boot certificates, a page fault occurs in Apple firmware code and EFI runtime services are disabled with the following logs: [Firmware Bug]: Page fault caused by firmware at PA: 0xffffb1edc0068000 WARNING: CPU: 3 PID: 104 at arch/x86/platform/efi/quirks.c:735 efi_crash_gracefully_on_page_fault+0x50/0xf0 (Removed some logs from here) Call Trace: <TASK> page_fault_oops+0x4f/0x2c0 ? search_bpf_extables+0x6b/0x80 ? search_module_extables+0x50/0x80 ? search_exception_tables+0x5b/0x60 kernelmode_fixup_or_oops+0x9e/0x110 __bad_area_nosemaphore+0x155/0x190 bad_area_nosemaphore+0x16/0x20 do_kern_addr_fault+0x8c/0xa0 exc_page_fault+0xd8/0x180 asm_exc_page_fault+0x1e/0x30 (Removed some logs from here) ? __efi_call+0x28/0x30 ? switch_mm+0x20/0x30 ? efi_call_rts+0x19a/0x8e0 ? process_one_work+0x222/0x3f0 ? worker_thread+0x4a/0x3d0 ? kthread+0x17a/0x1a0 ? process_one_work+0x3f0/0x3f0 ? set_kthread_struct+0x40/0x40 ? ret_from_fork+0x22/0x30 </TASK> ---[ end trace 1f82023595a5927f ]--- efi: Froze efi_rts_wq and disabled EFI Runtime Services integrity: Couldn't get size: 0x8000000000000015 integrity: MODSIGN: Couldn't get UEFI db list efi: EFI Runtime Services are disabled! integrity: Couldn't get size: 0x8000000000000015 integrity: Couldn't get UEFI dbx list integrity: Couldn't get size: 0x8000000000000015 integrity: Couldn't get mokx list integrity: Couldn't get size: 0x80000000 So we avoid reading these UEFI variables and thus prevent the crash. Cc: stable@vger.kernel.org Signed-off-by: Aditya Garg <gargaditya08@live.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-04-16 01:02:46 +08:00
#include <linux/dmi.h>
#include <linux/err.h>
#include <linux/efi.h>
#include <linux/slab.h>
#include <linux/ima.h>
#include <keys/asymmetric-type.h>
#include <keys/system_keyring.h>
#include "../integrity.h"
#include "keyring_handler.h"
efi: Do not import certificates from UEFI Secure Boot for T2 Macs On Apple T2 Macs, when Linux attempts to read the db and dbx efi variables at early boot to load UEFI Secure Boot certificates, a page fault occurs in Apple firmware code and EFI runtime services are disabled with the following logs: [Firmware Bug]: Page fault caused by firmware at PA: 0xffffb1edc0068000 WARNING: CPU: 3 PID: 104 at arch/x86/platform/efi/quirks.c:735 efi_crash_gracefully_on_page_fault+0x50/0xf0 (Removed some logs from here) Call Trace: <TASK> page_fault_oops+0x4f/0x2c0 ? search_bpf_extables+0x6b/0x80 ? search_module_extables+0x50/0x80 ? search_exception_tables+0x5b/0x60 kernelmode_fixup_or_oops+0x9e/0x110 __bad_area_nosemaphore+0x155/0x190 bad_area_nosemaphore+0x16/0x20 do_kern_addr_fault+0x8c/0xa0 exc_page_fault+0xd8/0x180 asm_exc_page_fault+0x1e/0x30 (Removed some logs from here) ? __efi_call+0x28/0x30 ? switch_mm+0x20/0x30 ? efi_call_rts+0x19a/0x8e0 ? process_one_work+0x222/0x3f0 ? worker_thread+0x4a/0x3d0 ? kthread+0x17a/0x1a0 ? process_one_work+0x3f0/0x3f0 ? set_kthread_struct+0x40/0x40 ? ret_from_fork+0x22/0x30 </TASK> ---[ end trace 1f82023595a5927f ]--- efi: Froze efi_rts_wq and disabled EFI Runtime Services integrity: Couldn't get size: 0x8000000000000015 integrity: MODSIGN: Couldn't get UEFI db list efi: EFI Runtime Services are disabled! integrity: Couldn't get size: 0x8000000000000015 integrity: Couldn't get UEFI dbx list integrity: Couldn't get size: 0x8000000000000015 integrity: Couldn't get mokx list integrity: Couldn't get size: 0x80000000 So we avoid reading these UEFI variables and thus prevent the crash. Cc: stable@vger.kernel.org Signed-off-by: Aditya Garg <gargaditya08@live.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-04-16 01:02:46 +08:00
/*
* On T2 Macs reading the db and dbx efi variables to load UEFI Secure Boot
* certificates causes occurrence of a page fault in Apple's firmware and
* a crash disabling EFI runtime services. The following quirk skips reading
* these variables.
*/
static const struct dmi_system_id uefi_skip_cert[] = {
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,1") },
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,2") },
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,3") },
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro15,4") },
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,1") },
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,2") },
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,3") },
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookPro16,4") },
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir8,1") },
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir8,2") },
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacBookAir9,1") },
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "Macmini8,1") },
efi: Do not import certificates from UEFI Secure Boot for T2 Macs On Apple T2 Macs, when Linux attempts to read the db and dbx efi variables at early boot to load UEFI Secure Boot certificates, a page fault occurs in Apple firmware code and EFI runtime services are disabled with the following logs: [Firmware Bug]: Page fault caused by firmware at PA: 0xffffb1edc0068000 WARNING: CPU: 3 PID: 104 at arch/x86/platform/efi/quirks.c:735 efi_crash_gracefully_on_page_fault+0x50/0xf0 (Removed some logs from here) Call Trace: <TASK> page_fault_oops+0x4f/0x2c0 ? search_bpf_extables+0x6b/0x80 ? search_module_extables+0x50/0x80 ? search_exception_tables+0x5b/0x60 kernelmode_fixup_or_oops+0x9e/0x110 __bad_area_nosemaphore+0x155/0x190 bad_area_nosemaphore+0x16/0x20 do_kern_addr_fault+0x8c/0xa0 exc_page_fault+0xd8/0x180 asm_exc_page_fault+0x1e/0x30 (Removed some logs from here) ? __efi_call+0x28/0x30 ? switch_mm+0x20/0x30 ? efi_call_rts+0x19a/0x8e0 ? process_one_work+0x222/0x3f0 ? worker_thread+0x4a/0x3d0 ? kthread+0x17a/0x1a0 ? process_one_work+0x3f0/0x3f0 ? set_kthread_struct+0x40/0x40 ? ret_from_fork+0x22/0x30 </TASK> ---[ end trace 1f82023595a5927f ]--- efi: Froze efi_rts_wq and disabled EFI Runtime Services integrity: Couldn't get size: 0x8000000000000015 integrity: MODSIGN: Couldn't get UEFI db list efi: EFI Runtime Services are disabled! integrity: Couldn't get size: 0x8000000000000015 integrity: Couldn't get UEFI dbx list integrity: Couldn't get size: 0x8000000000000015 integrity: Couldn't get mokx list integrity: Couldn't get size: 0x80000000 So we avoid reading these UEFI variables and thus prevent the crash. Cc: stable@vger.kernel.org Signed-off-by: Aditya Garg <gargaditya08@live.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-04-16 01:02:46 +08:00
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "MacPro7,1") },
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "iMac20,1") },
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "iMac20,2") },
{ UEFI_QUIRK_SKIP_CERT("Apple Inc.", "iMacPro1,1") },
efi: Do not import certificates from UEFI Secure Boot for T2 Macs On Apple T2 Macs, when Linux attempts to read the db and dbx efi variables at early boot to load UEFI Secure Boot certificates, a page fault occurs in Apple firmware code and EFI runtime services are disabled with the following logs: [Firmware Bug]: Page fault caused by firmware at PA: 0xffffb1edc0068000 WARNING: CPU: 3 PID: 104 at arch/x86/platform/efi/quirks.c:735 efi_crash_gracefully_on_page_fault+0x50/0xf0 (Removed some logs from here) Call Trace: <TASK> page_fault_oops+0x4f/0x2c0 ? search_bpf_extables+0x6b/0x80 ? search_module_extables+0x50/0x80 ? search_exception_tables+0x5b/0x60 kernelmode_fixup_or_oops+0x9e/0x110 __bad_area_nosemaphore+0x155/0x190 bad_area_nosemaphore+0x16/0x20 do_kern_addr_fault+0x8c/0xa0 exc_page_fault+0xd8/0x180 asm_exc_page_fault+0x1e/0x30 (Removed some logs from here) ? __efi_call+0x28/0x30 ? switch_mm+0x20/0x30 ? efi_call_rts+0x19a/0x8e0 ? process_one_work+0x222/0x3f0 ? worker_thread+0x4a/0x3d0 ? kthread+0x17a/0x1a0 ? process_one_work+0x3f0/0x3f0 ? set_kthread_struct+0x40/0x40 ? ret_from_fork+0x22/0x30 </TASK> ---[ end trace 1f82023595a5927f ]--- efi: Froze efi_rts_wq and disabled EFI Runtime Services integrity: Couldn't get size: 0x8000000000000015 integrity: MODSIGN: Couldn't get UEFI db list efi: EFI Runtime Services are disabled! integrity: Couldn't get size: 0x8000000000000015 integrity: Couldn't get UEFI dbx list integrity: Couldn't get size: 0x8000000000000015 integrity: Couldn't get mokx list integrity: Couldn't get size: 0x80000000 So we avoid reading these UEFI variables and thus prevent the crash. Cc: stable@vger.kernel.org Signed-off-by: Aditya Garg <gargaditya08@live.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-04-16 01:02:46 +08:00
{ }
};
/*
* Look to see if a UEFI variable called MokIgnoreDB exists and return true if
* it does.
*
* This UEFI variable is set by the shim if a user tells the shim to not use
* the certs/hashes in the UEFI db variable for verification purposes. If it
* is set, we should ignore the db variable also and the true return indicates
* this.
*/
static __init bool uefi_check_ignore_db(void)
{
efi_status_t status;
unsigned int db = 0;
unsigned long size = sizeof(db);
efi_guid_t guid = EFI_SHIM_LOCK_GUID;
status = efi.get_variable(L"MokIgnoreDB", &guid, NULL, &size, &db);
return status == EFI_SUCCESS;
}
/*
* Get a certificate list blob from the named EFI variable.
*/
static __init void *get_cert_list(efi_char16_t *name, efi_guid_t *guid,
unsigned long *size, efi_status_t *status)
{
unsigned long lsize = 4;
unsigned long tmpdb[4];
void *db;
*status = efi.get_variable(name, guid, NULL, &lsize, &tmpdb);
if (*status == EFI_NOT_FOUND)
return NULL;
if (*status != EFI_BUFFER_TOO_SMALL) {
pr_err("Couldn't get size: 0x%lx\n", *status);
return NULL;
}
db = kmalloc(lsize, GFP_KERNEL);
if (!db)
return NULL;
*status = efi.get_variable(name, guid, NULL, &lsize, db);
if (*status != EFI_SUCCESS) {
kfree(db);
pr_err("Error reading db var: 0x%lx\n", *status);
return NULL;
}
*size = lsize;
return db;
}
/*
* load_moklist_certs() - Load MokList certs
*
* Load the certs contained in the UEFI MokListRT database into the
* platform trusted keyring.
*
* This routine checks the EFI MOK config table first. If and only if
* that fails, this routine uses the MokListRT ordinary UEFI variable.
*
* Return: Status
*/
static int __init load_moklist_certs(void)
{
struct efi_mokvar_table_entry *mokvar_entry;
efi_guid_t mok_var = EFI_SHIM_LOCK_GUID;
void *mok;
unsigned long moksize;
efi_status_t status;
int rc;
/* First try to load certs from the EFI MOKvar config table.
* It's not an error if the MOKvar config table doesn't exist
* or the MokListRT entry is not found in it.
*/
mokvar_entry = efi_mokvar_entry_find("MokListRT");
if (mokvar_entry) {
rc = parse_efi_signature_list("UEFI:MokListRT (MOKvar table)",
mokvar_entry->data,
mokvar_entry->data_size,
get_handler_for_mok);
/* All done if that worked. */
if (!rc)
return rc;
pr_err("Couldn't parse MokListRT signatures from EFI MOKvar config table: %d\n",
rc);
}
/* Get MokListRT. It might not exist, so it isn't an error
* if we can't get it.
*/
mok = get_cert_list(L"MokListRT", &mok_var, &moksize, &status);
if (mok) {
rc = parse_efi_signature_list("UEFI:MokListRT",
mok, moksize, get_handler_for_mok);
kfree(mok);
if (rc)
pr_err("Couldn't parse MokListRT signatures: %d\n", rc);
return rc;
}
if (status == EFI_NOT_FOUND)
pr_debug("MokListRT variable wasn't found\n");
else
pr_info("Couldn't get UEFI MokListRT\n");
return 0;
}
/*
* load_uefi_certs() - Load certs from UEFI sources
*
* Load the certs contained in the UEFI databases into the platform trusted
* keyring and the UEFI blacklisted X.509 cert SHA256 hashes into the blacklist
* keyring.
*/
static int __init load_uefi_certs(void)
{
efi_guid_t secure_var = EFI_IMAGE_SECURITY_DATABASE_GUID;
efi_guid_t mok_var = EFI_SHIM_LOCK_GUID;
void *db = NULL, *dbx = NULL, *mokx = NULL;
unsigned long dbsize = 0, dbxsize = 0, mokxsize = 0;
efi_status_t status;
int rc = 0;
efi: Do not import certificates from UEFI Secure Boot for T2 Macs On Apple T2 Macs, when Linux attempts to read the db and dbx efi variables at early boot to load UEFI Secure Boot certificates, a page fault occurs in Apple firmware code and EFI runtime services are disabled with the following logs: [Firmware Bug]: Page fault caused by firmware at PA: 0xffffb1edc0068000 WARNING: CPU: 3 PID: 104 at arch/x86/platform/efi/quirks.c:735 efi_crash_gracefully_on_page_fault+0x50/0xf0 (Removed some logs from here) Call Trace: <TASK> page_fault_oops+0x4f/0x2c0 ? search_bpf_extables+0x6b/0x80 ? search_module_extables+0x50/0x80 ? search_exception_tables+0x5b/0x60 kernelmode_fixup_or_oops+0x9e/0x110 __bad_area_nosemaphore+0x155/0x190 bad_area_nosemaphore+0x16/0x20 do_kern_addr_fault+0x8c/0xa0 exc_page_fault+0xd8/0x180 asm_exc_page_fault+0x1e/0x30 (Removed some logs from here) ? __efi_call+0x28/0x30 ? switch_mm+0x20/0x30 ? efi_call_rts+0x19a/0x8e0 ? process_one_work+0x222/0x3f0 ? worker_thread+0x4a/0x3d0 ? kthread+0x17a/0x1a0 ? process_one_work+0x3f0/0x3f0 ? set_kthread_struct+0x40/0x40 ? ret_from_fork+0x22/0x30 </TASK> ---[ end trace 1f82023595a5927f ]--- efi: Froze efi_rts_wq and disabled EFI Runtime Services integrity: Couldn't get size: 0x8000000000000015 integrity: MODSIGN: Couldn't get UEFI db list efi: EFI Runtime Services are disabled! integrity: Couldn't get size: 0x8000000000000015 integrity: Couldn't get UEFI dbx list integrity: Couldn't get size: 0x8000000000000015 integrity: Couldn't get mokx list integrity: Couldn't get size: 0x80000000 So we avoid reading these UEFI variables and thus prevent the crash. Cc: stable@vger.kernel.org Signed-off-by: Aditya Garg <gargaditya08@live.com> Reviewed-by: Mimi Zohar <zohar@linux.ibm.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2022-04-16 01:02:46 +08:00
const struct dmi_system_id *dmi_id;
dmi_id = dmi_first_match(uefi_skip_cert);
if (dmi_id) {
pr_err("Reading UEFI Secure Boot Certs is not supported on T2 Macs.\n");
return false;
}
if (!efi_rt_services_supported(EFI_RT_SUPPORTED_GET_VARIABLE))
return false;
/* Get db and dbx. They might not exist, so it isn't an error
* if we can't get them.
*/
if (!uefi_check_ignore_db()) {
db = get_cert_list(L"db", &secure_var, &dbsize, &status);
if (!db) {
if (status == EFI_NOT_FOUND)
pr_debug("MODSIGN: db variable wasn't found\n");
else
pr_err("MODSIGN: Couldn't get UEFI db list\n");
} else {
rc = parse_efi_signature_list("UEFI:db",
db, dbsize, get_handler_for_db);
if (rc)
pr_err("Couldn't parse db signatures: %d\n",
rc);
kfree(db);
}
}
dbx = get_cert_list(L"dbx", &secure_var, &dbxsize, &status);
if (!dbx) {
if (status == EFI_NOT_FOUND)
pr_debug("dbx variable wasn't found\n");
else
pr_info("Couldn't get UEFI dbx list\n");
} else {
rc = parse_efi_signature_list("UEFI:dbx",
dbx, dbxsize,
get_handler_for_dbx);
if (rc)
pr_err("Couldn't parse dbx signatures: %d\n", rc);
kfree(dbx);
}
/* the MOK/MOKx can not be trusted when secure boot is disabled */
if (!arch_ima_get_secureboot())
return 0;
mokx = get_cert_list(L"MokListXRT", &mok_var, &mokxsize, &status);
if (!mokx) {
if (status == EFI_NOT_FOUND)
pr_debug("mokx variable wasn't found\n");
else
pr_info("Couldn't get mokx list\n");
} else {
rc = parse_efi_signature_list("UEFI:MokListXRT",
mokx, mokxsize,
get_handler_for_dbx);
if (rc)
pr_err("Couldn't parse mokx signatures %d\n", rc);
kfree(mokx);
}
/* Load the MokListRT certs */
rc = load_moklist_certs();
return rc;
}
late_initcall(load_uefi_certs);