We recently added functions for storing/restoring variables
from a file to a memory backed buffer marked as __efi_runtime_data
commit f1f990a8c958 ("efi_loader: memory buffer for variables")
commit 5f7dcf079de8 ("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(a)linaro.org>
---
Fixes since v1:
- Better describe efi_var_collect() and it's args
- Check the the StMM provided buffer is big enough for some variables,
instead of just > 2
- Merged runtime functions for GetVariable() and GetNextVariable()
since they were identical across the 2 implementations
include/efi_variable.h | 74 ++++++++++++++++++++++
lib/efi_loader/Makefile | 2 +-
lib/efi_loader/efi_var_common.c | 22 +++++++
lib/efi_loader/efi_var_file.c | 25 +++-----
lib/efi_loader/efi_var_mem.c | 70 ++++++++++++++++++++-
lib/efi_loader/efi_variable.c | 101 +-----------------------------
lib/efi_loader/efi_variable_tee.c | 81 +++++++++++++-----------
7 files changed, 221 insertions(+), 154 deletions(-)
diff --git a/include/efi_variable.h b/include/efi_variable.h
index 2c629e4dca92..60491cb64025 100644
--- a/include/efi_variable.h
+++ b/include/efi_variable.h
@@ -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
diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile
index 441ac9432e99..9bad1d159b03 100644
--- a/lib/efi_loader/Makefile
+++ b/lib/efi_loader/Makefile
@@ -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
diff --git a/lib/efi_loader/efi_var_common.c b/lib/efi_loader/efi_var_common.c
index ee2e67bc8cbf..453cbce5c83a 100644
--- a/lib/efi_loader/efi_var_common.c
+++ b/lib/efi_loader/efi_var_common.c
@@ -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
diff --git a/lib/efi_loader/efi_var_file.c b/lib/efi_loader/efi_var_file.c
index 6f9d76f2a2d5..b171d2d1a8f7 100644
--- a/lib/efi_loader/efi_var_file.c
+++ b/lib/efi_loader/efi_var_file.c
@@ -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;
diff --git a/lib/efi_loader/efi_var_mem.c b/lib/efi_loader/efi_var_mem.c
index 7a2dba7dc263..fd97d5b56300 100644
--- a/lib/efi_loader/efi_var_mem.c
+++ b/lib/efi_loader/efi_var_mem.c
@@ -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;
/**
@@ -264,3 +264,71 @@ 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;
+}
diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index 39a848290380..e509d6dbf0cf 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -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()
*
diff --git a/lib/efi_loader/efi_variable_tee.c b/lib/efi_loader/efi_variable_tee.c
index 9920351a403e..8a3ff8c59386 100644
--- a/lib/efi_loader/efi_variable_tee.c
+++ b/lib/efi_loader/efi_variable_tee.c
@@ -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 +239,31 @@ 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 i.e en-US. */
+ 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.
+ * Ref: StandaloneMmPkg/Drivers/StandaloneMmCpu/AArch64/EventHandle.c
+ * sizeof (EFI_MM_COMMUNICATE_HEADER) instead the size minus the flexible
+ * array member
+ * This is guaranteed to be > 2 due to checks on the beggining.
+ */
+ *size -= 2;
out:
free(comm_buf);
return ret;
@@ -592,39 +617,6 @@ 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 +666,10 @@ 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 +682,18 @@ 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 +713,11 @@ 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;
--
2.28.0.rc1
