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efi_loader: Enable run-time variable support for tee based variables

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We recently added functions for storing/restoring variables
from a file to a memory backed buffer marked as __efi_runtime_data
commit f1f990a8c9 ("efi_loader: memory buffer for variables")
commit 5f7dcf079d ("efi_loader: UEFI variable persistence")

Using the same idea we now can support GetVariable() and GetNextVariable()
on the OP-TEE based variables as well.

So let's re-arrange the code a bit and move the commmon code for
accessing variables out of efi_variable.c. Create common functions for
reading variables from memory that both implementations can use on
run-time. Then just use those functions in the run-time variants of the
OP-TEE based EFI variable implementation and initialize the memory
buffer on ExitBootServices()

Signed-off-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Reviewed-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
This commit is contained in:
Ilias Apalodimas 2020-07-23 15:49:49 +03:00 committed by Heinrich Schuchardt
parent db94dfbd52
commit e01aed47d6
7 changed files with 222 additions and 154 deletions
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74
include/efi_variable.h
View file

@ -142,6 +142,22 @@ struct efi_var_file {
*/
efi_status_t efi_var_to_file(void);
/**
* efi_var_collect() - collect variables in buffer
*
* A buffer is allocated and filled with variables in a format ready to be
* written to disk.
*
* @bufp: pointer to pointer of buffer with collected variables
* @lenp: pointer to length of buffer
* @check_attr_mask: bitmask with required attributes of variables to be collected.
* variables are only collected if all of the required
* attributes are set.
* Return: status code
*/
efi_status_t __maybe_unused efi_var_collect(struct efi_var_file **bufp, loff_t *lenp,
u32 check_attr_mask);
/**
* efi_var_restore() - restore EFI variables from buffer
*
@ -233,4 +249,62 @@ efi_status_t efi_init_secure_state(void);
*/
enum efi_auth_var_type efi_auth_var_get_type(u16 *name, const efi_guid_t *guid);
/**
* efi_get_next_variable_name_mem() - Runtime common code across efi variable
* implementations for GetNextVariable()
* from the cached memory copy
* @variable_name_size: size of variable_name buffer in byte
* @variable_name: name of uefi variable's name in u16
* @vendor: vendor's guid
*
* Return: status code
*/
efi_status_t __efi_runtime
efi_get_next_variable_name_mem(efi_uintn_t *variable_name_size, u16 *variable_name,
efi_guid_t *vendor);
/**
* efi_get_variable_mem() - Runtime common code across efi variable
* implementations for GetVariable() from
* the cached memory copy
*
* @variable_name: name of the variable
* @vendor: vendor GUID
* @attributes: attributes of the variable
* @data_size: size of the buffer to which the variable value is copied
* @data: buffer to which the variable value is copied
* @timep: authentication time (seconds since start of epoch)
* Return: status code
*/
efi_status_t __efi_runtime
efi_get_variable_mem(u16 *variable_name, const efi_guid_t *vendor, u32 *attributes,
efi_uintn_t *data_size, void *data, u64 *timep);
/**
* efi_get_variable_runtime() - runtime implementation of GetVariable()
*
* @variable_name: name of the variable
* @guid: vendor GUID
* @attributes: attributes of the variable
* @data_size: size of the buffer to which the variable value is copied
* @data: buffer to which the variable value is copied
* Return: status code
*/
efi_status_t __efi_runtime EFIAPI
efi_get_variable_runtime(u16 *variable_name, const efi_guid_t *guid,
u32 *attributes, efi_uintn_t *data_size, void *data);
/**
* efi_get_next_variable_name_runtime() - runtime implementation of
* GetNextVariable()
*
* @variable_name_size: size of variable_name buffer in byte
* @variable_name: name of uefi variable's name in u16
* @guid: vendor's guid
* Return: status code
*/
efi_status_t __efi_runtime EFIAPI
efi_get_next_variable_name_runtime(efi_uintn_t *variable_name_size,
u16 *variable_name, efi_guid_t *guid);
#endif

2
lib/efi_loader/Makefile
View file

@ -37,11 +37,11 @@ obj-y += efi_setup.o
obj-$(CONFIG_EFI_UNICODE_COLLATION_PROTOCOL2) += efi_unicode_collation.o
obj-y += efi_var_common.o
obj-y += efi_var_mem.o
obj-y += efi_var_file.o
ifeq ($(CONFIG_EFI_MM_COMM_TEE),y)
obj-y += efi_variable_tee.o
else
obj-y += efi_variable.o
obj-y += efi_var_file.o
obj-$(CONFIG_EFI_VARIABLES_PRESEED) += efi_var_seed.o
endif
obj-y += efi_watchdog.o

22
lib/efi_loader/efi_var_common.c
View file

@ -166,6 +166,28 @@ efi_status_t EFIAPI efi_query_variable_info(
return EFI_EXIT(ret);
}
efi_status_t __efi_runtime EFIAPI
efi_get_variable_runtime(u16 *variable_name, const efi_guid_t *guid,
u32 *attributes, efi_uintn_t *data_size, void *data)
{
efi_status_t ret;
ret = efi_get_variable_mem(variable_name, guid, attributes, data_size, data, NULL);
/* Remove EFI_VARIABLE_READ_ONLY flag */
if (attributes)
*attributes &= EFI_VARIABLE_MASK;
return ret;
}
efi_status_t __efi_runtime EFIAPI
efi_get_next_variable_name_runtime(efi_uintn_t *variable_name_size,
u16 *variable_name, efi_guid_t *guid)
{
return efi_get_next_variable_name_mem(variable_name_size, variable_name, guid);
}
/**
* efi_set_secure_state - modify secure boot state variables
* @secure_boot: value of SecureBoot

25
lib/efi_loader/efi_var_file.c
View file

@ -46,18 +46,8 @@ static efi_status_t __maybe_unused efi_set_blk_dev_to_system_partition(void)
return EFI_SUCCESS;
}
/**
* efi_var_collect() - collect non-volatile variables in buffer
*
* A buffer is allocated and filled with all non-volatile variables in a
* format ready to be written to disk.
*
* @bufp: pointer to pointer of buffer with collected variables
* @lenp: pointer to length of buffer
* Return: status code
*/
static efi_status_t __maybe_unused efi_var_collect(struct efi_var_file **bufp,
loff_t *lenp)
efi_status_t __maybe_unused efi_var_collect(struct efi_var_file **bufp, loff_t *lenp,
u32 check_attr_mask)
{
size_t len = EFI_VAR_BUF_SIZE;
struct efi_var_file *buf;
@ -102,11 +92,10 @@ static efi_status_t __maybe_unused efi_var_collect(struct efi_var_file **bufp,
free(buf);
return ret;
}
if (!(var->attr & EFI_VARIABLE_NON_VOLATILE))
continue;
var->length = data_length;
var = (struct efi_var_entry *)
ALIGN((uintptr_t)data + data_length, 8);
if ((var->attr & check_attr_mask) == check_attr_mask) {
var->length = data_length;
var = (struct efi_var_entry *)ALIGN((uintptr_t)data + data_length, 8);
}
}
buf->reserved = 0;
@ -137,7 +126,7 @@ efi_status_t efi_var_to_file(void)
loff_t actlen;
int r;
ret = efi_var_collect(&buf, &len);
ret = efi_var_collect(&buf, &len, EFI_VARIABLE_NON_VOLATILE);
if (ret != EFI_SUCCESS)
goto error;

70
lib/efi_loader/efi_var_mem.c
View file

@ -10,7 +10,7 @@
#include <efi_variable.h>
#include <u-boot/crc.h>
static struct efi_var_file __efi_runtime_data *efi_var_buf;
struct efi_var_file __efi_runtime_data *efi_var_buf;
static struct efi_var_entry __efi_runtime_data *efi_current_var;
/**
@ -266,3 +266,71 @@ efi_status_t efi_var_mem_init(void)
return ret;
return ret;
}
efi_status_t __efi_runtime
efi_get_variable_mem(u16 *variable_name, const efi_guid_t *vendor, u32 *attributes,
efi_uintn_t *data_size, void *data, u64 *timep)
{
efi_uintn_t old_size;
struct efi_var_entry *var;
u16 *pdata;
if (!variable_name || !vendor || !data_size)
return EFI_INVALID_PARAMETER;
var = efi_var_mem_find(vendor, variable_name, NULL);
if (!var)
return EFI_NOT_FOUND;
if (attributes)
*attributes = var->attr;
if (timep)
*timep = var->time;
old_size = *data_size;
*data_size = var->length;
if (old_size < var->length)
return EFI_BUFFER_TOO_SMALL;
if (!data)
return EFI_INVALID_PARAMETER;
for (pdata = var->name; *pdata; ++pdata)
;
++pdata;
efi_memcpy_runtime(data, pdata, var->length);
return EFI_SUCCESS;
}
efi_status_t __efi_runtime
efi_get_next_variable_name_mem(efi_uintn_t *variable_name_size, u16 *variable_name,
efi_guid_t *vendor)
{
struct efi_var_entry *var;
efi_uintn_t old_size;
u16 *pdata;
if (!variable_name_size || !variable_name || !vendor)
return EFI_INVALID_PARAMETER;
efi_var_mem_find(vendor, variable_name, &var);
if (!var)
return EFI_NOT_FOUND;
for (pdata = var->name; *pdata; ++pdata)
;
++pdata;
old_size = *variable_name_size;
*variable_name_size = (uintptr_t)pdata - (uintptr_t)var->name;
if (old_size < *variable_name_size)
return EFI_BUFFER_TOO_SMALL;
efi_memcpy_runtime(variable_name, var->name, *variable_name_size);
efi_memcpy_runtime(vendor, &var->guid, sizeof(efi_guid_t));
return EFI_SUCCESS;
}

101
lib/efi_loader/efi_variable.c
View file

@ -282,68 +282,14 @@ efi_get_variable_int(u16 *variable_name, const efi_guid_t *vendor,
u32 *attributes, efi_uintn_t *data_size, void *data,
u64 *timep)
{
efi_uintn_t old_size;
struct efi_var_entry *var;
u16 *pdata;
if (!variable_name || !vendor || !data_size)
return EFI_INVALID_PARAMETER;
var = efi_var_mem_find(vendor, variable_name, NULL);
if (!var)
return EFI_NOT_FOUND;
if (attributes)
*attributes = var->attr;
if (timep)
*timep = var->time;
old_size = *data_size;
*data_size = var->length;
if (old_size < var->length)
return EFI_BUFFER_TOO_SMALL;
if (!data)
return EFI_INVALID_PARAMETER;
for (pdata = var->name; *pdata; ++pdata)
;
++pdata;
efi_memcpy_runtime(data, pdata, var->length);
return EFI_SUCCESS;
return efi_get_variable_mem(variable_name, vendor, attributes, data_size, data, timep);
}
efi_status_t __efi_runtime
efi_get_next_variable_name_int(efi_uintn_t *variable_name_size,
u16 *variable_name, efi_guid_t *vendor)
{
struct efi_var_entry *var;
efi_uintn_t old_size;
u16 *pdata;
if (!variable_name_size || !variable_name || !vendor)
return EFI_INVALID_PARAMETER;
efi_var_mem_find(vendor, variable_name, &var);
if (!var)
return EFI_NOT_FOUND;
for (pdata = var->name; *pdata; ++pdata)
;
++pdata;
old_size = *variable_name_size;
*variable_name_size = (uintptr_t)pdata - (uintptr_t)var->name;
if (old_size < *variable_name_size)
return EFI_BUFFER_TOO_SMALL;
efi_memcpy_runtime(variable_name, var->name, *variable_name_size);
efi_memcpy_runtime(vendor, &var->guid, sizeof(efi_guid_t));
return EFI_SUCCESS;
return efi_get_next_variable_name_mem(variable_name_size, variable_name, vendor);
}
efi_status_t efi_set_variable_int(u16 *variable_name, const efi_guid_t *vendor,
@ -504,49 +450,6 @@ efi_status_t __efi_runtime EFIAPI efi_query_variable_info_runtime(
return EFI_UNSUPPORTED;
}
/**
* efi_get_variable_runtime() - runtime implementation of GetVariable()
*
* @variable_name: name of the variable
* @vendor: vendor GUID
* @attributes: attributes of the variable
* @data_size: size of the buffer to which the variable value is copied
* @data: buffer to which the variable value is copied
* Return: status code
*/
static efi_status_t __efi_runtime EFIAPI
efi_get_variable_runtime(u16 *variable_name, const efi_guid_t *vendor,
u32 *attributes, efi_uintn_t *data_size, void *data)
{
efi_status_t ret;
ret = efi_get_variable_int(variable_name, vendor, attributes,
data_size, data, NULL);
/* Remove EFI_VARIABLE_READ_ONLY flag */
if (attributes)
*attributes &= EFI_VARIABLE_MASK;
return ret;
}
/**
* efi_get_next_variable_name_runtime() - runtime implementation of
* GetNextVariable()
*
* @variable_name_size: size of variable_name buffer in byte
* @variable_name: name of uefi variable's name in u16
* @vendor: vendor's guid
* Return: status code
*/
static efi_status_t __efi_runtime EFIAPI
efi_get_next_variable_name_runtime(efi_uintn_t *variable_name_size,
u16 *variable_name, efi_guid_t *vendor)
{
return efi_get_next_variable_name_int(variable_name_size, variable_name,
vendor);
}
/**
* efi_set_variable_runtime() - runtime implementation of SetVariable()
*

82
lib/efi_loader/efi_variable_tee.c
View file

@ -15,6 +15,8 @@
#include <malloc.h>
#include <mm_communication.h>
#define OPTEE_PAGE_SIZE BIT(12)
extern struct efi_var_file __efi_runtime_data *efi_var_buf;
static efi_uintn_t max_buffer_size; /* comm + var + func + data */
static efi_uintn_t max_payload_size; /* func + data */
@ -237,8 +239,32 @@ efi_status_t EFIAPI get_max_payload(efi_uintn_t *size)
if (ret != EFI_SUCCESS)
goto out;
/* Make sure the buffer is big enough for storing variables */
if (var_payload->size < MM_VARIABLE_ACCESS_HEADER_SIZE + 0x20) {
ret = EFI_DEVICE_ERROR;
goto out;
}
*size = var_payload->size;
/*
* Although the max payload is configurable on StMM, we only share a
* single page from OP-TEE for the non-secure buffer used to communicate
* with StMM. Since OP-TEE will reject to map anything bigger than that,
* make sure we are in bounds.
*/
if (*size > OPTEE_PAGE_SIZE)
*size = OPTEE_PAGE_SIZE - MM_COMMUNICATE_HEADER_SIZE -
MM_VARIABLE_COMMUNICATE_SIZE;
/*
* There seems to be a bug in EDK2 miscalculating the boundaries and
* size checks, so deduct 2 more bytes to fulfill this requirement. Fix
* it up here to ensure backwards compatibility with older versions
* (cf. StandaloneMmPkg/Drivers/StandaloneMmCpu/AArch64/EventHandle.c.
* sizeof (EFI_MM_COMMUNICATE_HEADER) instead the size minus the
* flexible array member).
*
* size is guaranteed to be > 2 due to checks on the beginning.
*/
*size -= 2;
out:
free(comm_buf);
return ret;
@ -592,39 +618,6 @@ out:
return ret;
}
/**
* efi_get_variable_runtime() - runtime implementation of GetVariable()
*
* @variable_name: name of the variable
* @guid: vendor GUID
* @attributes: attributes of the variable
* @data_size: size of the buffer to which the variable value is copied
* @data: buffer to which the variable value is copied
* Return: status code
*/
static efi_status_t __efi_runtime EFIAPI
efi_get_variable_runtime(u16 *variable_name, const efi_guid_t *guid,
u32 *attributes, efi_uintn_t *data_size, void *data)
{
return EFI_UNSUPPORTED;
}
/**
* efi_get_next_variable_name_runtime() - runtime implementation of
* GetNextVariable()
*
* @variable_name_size: size of variable_name buffer in byte
* @variable_name: name of uefi variable's name in u16
* @guid: vendor's guid
* Return: status code
*/
static efi_status_t __efi_runtime EFIAPI
efi_get_next_variable_name_runtime(efi_uintn_t *variable_name_size,
u16 *variable_name, efi_guid_t *guid)
{
return EFI_UNSUPPORTED;
}
/**
* efi_query_variable_info() - get information about EFI variables
*
@ -674,8 +667,10 @@ efi_set_variable_runtime(u16 *variable_name, const efi_guid_t *guid,
*/
void efi_variables_boot_exit_notify(void)
{
u8 *comm_buf;
efi_status_t ret;
u8 *comm_buf;
loff_t len;
struct efi_var_file *var_buf;
comm_buf = setup_mm_hdr(NULL, 0,
SMM_VARIABLE_FUNCTION_EXIT_BOOT_SERVICE, &ret);
@ -688,6 +683,18 @@ void efi_variables_boot_exit_notify(void)
log_err("Unable to notify StMM for ExitBootServices\n");
free(comm_buf);
/*
* Populate the list for runtime variables.
* asking EFI_VARIABLE_RUNTIME_ACCESS is redundant, since
* efi_var_mem_notify_exit_boot_services will clean those, but that's fine
*/
ret = efi_var_collect(&var_buf, &len, EFI_VARIABLE_RUNTIME_ACCESS);
if (ret != EFI_SUCCESS)
log_err("Can't populate EFI variables. No runtime variables will be available\n");
else
memcpy(efi_var_buf, var_buf, len);
free(var_buf);
/* Update runtime service table */
efi_runtime_services.query_variable_info =
efi_query_variable_info_runtime;
@ -707,6 +714,11 @@ efi_status_t efi_init_variables(void)
{
efi_status_t ret;
/* Create a cached copy of the variables that will be enabled on ExitBootServices() */
ret = efi_var_mem_init();
if (ret != EFI_SUCCESS)
return ret;
ret = get_max_payload(&max_payload_size);
if (ret != EFI_SUCCESS)
return ret;