We currently have two implementations of UEFI variables:
* variables provided via an OP-TEE module * variables stored in the U-Boot environment
Read only variables are up to now only implemented in the U-Boot environment implementation.
Provide a common interface for both implementations that allows handling read-only variables.
As variable access is limited to very few source files put variable related definitions into new include efi_variable.h instead of efi_loader.
Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de --- doc/api/efi.rst | 2 + include/efi_variable.h | 43 ++++++++ lib/efi_loader/Makefile | 1 + lib/efi_loader/efi_var_common.c | 78 +++++++++++++ lib/efi_loader/efi_variable.c | 175 ++++++++---------------------- lib/efi_loader/efi_variable_tee.c | 75 ++++--------- 6 files changed, 193 insertions(+), 181 deletions(-) create mode 100644 include/efi_variable.h create mode 100644 lib/efi_loader/efi_var_common.c
diff --git a/doc/api/efi.rst b/doc/api/efi.rst index d5114f05b3..cb2a1c897e 100644 --- a/doc/api/efi.rst +++ b/doc/api/efi.rst @@ -93,6 +93,8 @@ Runtime services Variable services ~~~~~~~~~~~~~~~~~
+.. kernel-doc:: include/efi_variable.h + :internal: .. kernel-doc:: lib/efi_loader/efi_variable.c :internal:
diff --git a/include/efi_variable.h b/include/efi_variable.h new file mode 100644 index 0000000000..6789118eba --- /dev/null +++ b/include/efi_variable.h @@ -0,0 +1,43 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Copyright (c) 2020, Heinrich Schuchardt xypron.glpk@gmx.de + */ + +#ifndef _EFI_VARIABLE_H +#define _EFI_VARIABLE_H + +#include <linux/bitops.h> + +#define EFI_VARIABLE_READ_ONLY BIT(31) + +/** + * efi_get_variable() - retrieve value of a UEFI variable + * + * @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_get_variable_int(u16 *variable_name, const efi_guid_t *vendor, + u32 *attributes, efi_uintn_t *data_size, + void *data, u64 *timep); + +/** + * efi_set_variable() - set value of a UEFI variable + * + * @variable_name: name of the variable + * @vendor: vendor GUID + * @attributes: attributes of the variable + * @data_size: size of the buffer with the variable value + * @data: buffer with the variable value + * @ro_check: check the read only read only bit in attributes + * Return: status code + */ +efi_status_t efi_set_variable_int(u16 *variable_name, const efi_guid_t *vendor, + u32 attributes, efi_uintn_t data_size, + const void *data, bool ro_check); + +#endif diff --git a/lib/efi_loader/Makefile b/lib/efi_loader/Makefile index 57c7e66ea0..7eddd7ef37 100644 --- a/lib/efi_loader/Makefile +++ b/lib/efi_loader/Makefile @@ -35,6 +35,7 @@ obj-y += efi_root_node.o obj-y += efi_runtime.o obj-y += efi_setup.o obj-$(CONFIG_EFI_UNICODE_COLLATION_PROTOCOL2) += efi_unicode_collation.o +obj-y += efi_var_common.o ifeq ($(CONFIG_EFI_MM_COMM_TEE),y) obj-y += efi_variable_tee.o else diff --git a/lib/efi_loader/efi_var_common.c b/lib/efi_loader/efi_var_common.c new file mode 100644 index 0000000000..6a4efa3f27 --- /dev/null +++ b/lib/efi_loader/efi_var_common.c @@ -0,0 +1,78 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * UEFI runtime variable services + * + * Copyright (c) 2020, Heinrich Schuchardt xypron.glpk@gmx.de + */ + +#include <common.h> +#include <efi_loader.h> +#include <efi_variable.h> + +/** + * efi_efi_get_variable() - retrieve value of a UEFI variable + * + * This function implements the GetVariable runtime service. + * + * See the Unified Extensible Firmware Interface (UEFI) specification for + * details. + * + * @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 + */ +efi_status_t EFIAPI efi_get_variable(u16 *variable_name, + const efi_guid_t *vendor, u32 *attributes, + efi_uintn_t *data_size, void *data) +{ + efi_status_t ret; + + EFI_ENTRY(""%ls" %pUl %p %p %p", variable_name, vendor, attributes, + data_size, data); + + 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 EFI_EXIT(ret); +} + +/** + * efi_set_variable() - set value of a UEFI variable + * + * This function implements the SetVariable runtime service. + * + * See the Unified Extensible Firmware Interface (UEFI) specification for + * details. + * + * @variable_name: name of the variable + * @vendor: vendor GUID + * @attributes: attributes of the variable + * @data_size: size of the buffer with the variable value + * @data: buffer with the variable value + * Return: status code + */ +efi_status_t EFIAPI efi_set_variable(u16 *variable_name, + const efi_guid_t *vendor, u32 attributes, + efi_uintn_t data_size, const void *data) +{ + efi_status_t ret; + + EFI_ENTRY(""%ls" %pUl %x %zu %p", variable_name, vendor, attributes, + data_size, data); + + /* Make sure that the EFI_VARIABLE_READ_ONLY flag is not set */ + if (attributes & ~(u32)EFI_VARIABLE_MASK) + ret = EFI_INVALID_PARAMETER; + else + ret = efi_set_variable_int(variable_name, vendor, attributes, + data_size, data, true); + + return EFI_EXIT(ret); +} diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c index efaba869ef..6ec1f97326 100644 --- a/lib/efi_loader/efi_variable.c +++ b/lib/efi_loader/efi_variable.c @@ -7,6 +7,7 @@
#include <common.h> #include <efi_loader.h> +#include <efi_variable.h> #include <env.h> #include <env_internal.h> #include <hexdump.h> @@ -15,7 +16,6 @@ #include <search.h> #include <uuid.h> #include <crypto/pkcs7_parser.h> -#include <linux/bitops.h> #include <linux/compat.h> #include <u-boot/crc.h>
@@ -30,21 +30,6 @@ static bool efi_secure_boot; static enum efi_secure_mode efi_secure_mode; static u8 efi_vendor_keys;
-#define READ_ONLY BIT(31) - -static efi_status_t efi_get_variable_common(u16 *variable_name, - const efi_guid_t *vendor, - u32 *attributes, - efi_uintn_t *data_size, void *data, - u64 *timep); - -static efi_status_t efi_set_variable_common(u16 *variable_name, - const efi_guid_t *vendor, - u32 attributes, - efi_uintn_t data_size, - const void *data, - bool ro_check); - /* * Mapping between EFI variables and u-boot variables: * @@ -155,7 +140,7 @@ static const char *parse_attr(const char *str, u32 *attrp, u64 *timep) str++;
if ((s = prefix(str, "ro"))) { - attr |= READ_ONLY; + attr |= EFI_VARIABLE_READ_ONLY; } else if ((s = prefix(str, "nv"))) { attr |= EFI_VARIABLE_NON_VOLATILE; } else if ((s = prefix(str, "boot"))) { @@ -203,29 +188,29 @@ static efi_status_t efi_set_secure_state(u8 secure_boot, u8 setup_mode,
attributes = EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS | - READ_ONLY; - ret = efi_set_variable_common(L"SecureBoot", &efi_global_variable_guid, - attributes, sizeof(secure_boot), - &secure_boot, false); + EFI_VARIABLE_READ_ONLY; + ret = efi_set_variable_int(L"SecureBoot", &efi_global_variable_guid, + attributes, sizeof(secure_boot), + &secure_boot, false); if (ret != EFI_SUCCESS) goto err;
- ret = efi_set_variable_common(L"SetupMode", &efi_global_variable_guid, - attributes, sizeof(setup_mode), - &setup_mode, false); + ret = efi_set_variable_int(L"SetupMode", &efi_global_variable_guid, + attributes, sizeof(setup_mode), + &setup_mode, false); if (ret != EFI_SUCCESS) goto err;
- ret = efi_set_variable_common(L"AuditMode", &efi_global_variable_guid, - attributes, sizeof(audit_mode), - &audit_mode, false); + ret = efi_set_variable_int(L"AuditMode", &efi_global_variable_guid, + attributes, sizeof(audit_mode), + &audit_mode, false); if (ret != EFI_SUCCESS) goto err;
- ret = efi_set_variable_common(L"DeployedMode", - &efi_global_variable_guid, attributes, - sizeof(deployed_mode), &deployed_mode, - false); + ret = efi_set_variable_int(L"DeployedMode", + &efi_global_variable_guid, attributes, + sizeof(deployed_mode), &deployed_mode, + false); err: return ret; } @@ -235,7 +220,7 @@ err: * @mode: new state * * Depending on @mode, secure boot related variables are updated. - * Those variables are *read-only* for users, efi_set_variable_common() + * Those variables are *read-only* for users, efi_set_variable_int() * is called here. * * Return: status code @@ -254,10 +239,10 @@ static efi_status_t efi_transfer_secure_state(enum efi_secure_mode mode)
efi_secure_boot = true; } else if (mode == EFI_MODE_AUDIT) { - ret = efi_set_variable_common(L"PK", &efi_global_variable_guid, - EFI_VARIABLE_BOOTSERVICE_ACCESS | - EFI_VARIABLE_RUNTIME_ACCESS, - 0, NULL, false); + ret = efi_set_variable_int(L"PK", &efi_global_variable_guid, + EFI_VARIABLE_BOOTSERVICE_ACCESS | + EFI_VARIABLE_RUNTIME_ACCESS, + 0, NULL, false); if (ret != EFI_SUCCESS) goto err;
@@ -309,8 +294,8 @@ static efi_status_t efi_init_secure_state(void) */
size = 0; - ret = efi_get_variable_common(L"PK", &efi_global_variable_guid, - NULL, &size, NULL, NULL); + ret = efi_get_variable_int(L"PK", &efi_global_variable_guid, + NULL, &size, NULL, NULL); if (ret == EFI_BUFFER_TOO_SMALL) { if (IS_ENABLED(CONFIG_EFI_SECURE_BOOT)) mode = EFI_MODE_USER; @@ -327,13 +312,13 @@ static efi_status_t efi_init_secure_state(void)
ret = efi_transfer_secure_state(mode); if (ret == EFI_SUCCESS) - ret = efi_set_variable_common(L"VendorKeys", - &efi_global_variable_guid, - EFI_VARIABLE_BOOTSERVICE_ACCESS | - EFI_VARIABLE_RUNTIME_ACCESS | - READ_ONLY, - sizeof(efi_vendor_keys), - &efi_vendor_keys, false); + ret = efi_set_variable_int(L"VendorKeys", + &efi_global_variable_guid, + EFI_VARIABLE_BOOTSERVICE_ACCESS | + EFI_VARIABLE_RUNTIME_ACCESS | + EFI_VARIABLE_READ_ONLY, + sizeof(efi_vendor_keys), + &efi_vendor_keys, false);
err: return ret; @@ -599,11 +584,9 @@ static efi_status_t efi_variable_authenticate(u16 *variable, } #endif /* CONFIG_EFI_SECURE_BOOT */
-static efi_status_t efi_get_variable_common(u16 *variable_name, - const efi_guid_t *vendor, - u32 *attributes, - efi_uintn_t *data_size, void *data, - u64 *timep) +efi_status_t efi_get_variable_int(u16 *variable_name, const efi_guid_t *vendor, + u32 *attributes, efi_uintn_t *data_size, + void *data, u64 *timep) { char *native_name; efi_status_t ret; @@ -684,40 +667,11 @@ static efi_status_t efi_get_variable_common(u16 *variable_name,
out: if (attributes) - *attributes = attr & EFI_VARIABLE_MASK; + *attributes = attr;
return ret; }
-/** - * efi_efi_get_variable() - retrieve value of a UEFI variable - * - * This function implements the GetVariable runtime service. - * - * See the Unified Extensible Firmware Interface (UEFI) specification for - * details. - * - * @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 - */ -efi_status_t EFIAPI efi_get_variable(u16 *variable_name, - const efi_guid_t *vendor, u32 *attributes, - efi_uintn_t *data_size, void *data) -{ - efi_status_t ret; - - EFI_ENTRY(""%ls" %pUl %p %p %p", variable_name, vendor, attributes, - data_size, data); - - ret = efi_get_variable_common(variable_name, vendor, attributes, - data_size, data, NULL); - return EFI_EXIT(ret); -} - static char *efi_variables_list; static char *efi_cur_variable;
@@ -881,12 +835,9 @@ efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size, return EFI_EXIT(ret); }
-static efi_status_t efi_set_variable_common(u16 *variable_name, - const efi_guid_t *vendor, - u32 attributes, - efi_uintn_t data_size, - const void *data, - bool ro_check) +efi_status_t efi_set_variable_int(u16 *variable_name, const efi_guid_t *vendor, + u32 attributes, efi_uintn_t data_size, + const void *data, bool ro_check) { char *native_name = NULL, *old_data = NULL, *val = NULL, *s; efi_uintn_t old_size; @@ -909,15 +860,15 @@ static efi_status_t efi_set_variable_common(u16 *variable_name, /* check if a variable exists */ old_size = 0; attr = 0; - ret = efi_get_variable_common(variable_name, vendor, &attr, - &old_size, NULL, &time); + ret = efi_get_variable_int(variable_name, vendor, &attr, + &old_size, NULL, &time); append = !!(attributes & EFI_VARIABLE_APPEND_WRITE); attributes &= ~(u32)EFI_VARIABLE_APPEND_WRITE; delete = !append && (!data_size || !attributes);
/* check attributes */ if (old_size) { - if (ro_check && (attr & READ_ONLY)) { + if (ro_check && (attr & EFI_VARIABLE_READ_ONLY)) { ret = EFI_WRITE_PROTECTED; goto err; } @@ -925,8 +876,8 @@ static efi_status_t efi_set_variable_common(u16 *variable_name, /* attributes won't be changed */ if (!delete && ((ro_check && attr != attributes) || - (!ro_check && ((attr & ~(u32)READ_ONLY) - != (attributes & ~(u32)READ_ONLY))))) { + (!ro_check && ((attr & ~(u32)EFI_VARIABLE_READ_ONLY) + != (attributes & ~(u32)EFI_VARIABLE_READ_ONLY))))) { ret = EFI_INVALID_PARAMETER; goto err; } @@ -1000,8 +951,8 @@ static efi_status_t efi_set_variable_common(u16 *variable_name, ret = EFI_OUT_OF_RESOURCES; goto err; } - ret = efi_get_variable_common(variable_name, vendor, - &attr, &old_size, old_data, NULL); + ret = efi_get_variable_int(variable_name, vendor, + &attr, &old_size, old_data, NULL); if (ret != EFI_SUCCESS) goto err; } else { @@ -1021,7 +972,7 @@ static efi_status_t efi_set_variable_common(u16 *variable_name, /* * store attributes */ - attributes &= (READ_ONLY | + attributes &= (EFI_VARIABLE_READ_ONLY | EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS | @@ -1030,7 +981,7 @@ static efi_status_t efi_set_variable_common(u16 *variable_name, while (attributes) { attr = 1 << (ffs(attributes) - 1);
- if (attr == READ_ONLY) { + if (attr == EFI_VARIABLE_READ_ONLY) { s += sprintf(s, "ro"); } else if (attr == EFI_VARIABLE_NON_VOLATILE) { s += sprintf(s, "nv"); @@ -1084,12 +1035,12 @@ out: /* update VendorKeys */ if (vendor_keys_modified & efi_vendor_keys) { efi_vendor_keys = 0; - ret = efi_set_variable_common( + ret = efi_set_variable_int( L"VendorKeys", &efi_global_variable_guid, EFI_VARIABLE_BOOTSERVICE_ACCESS | EFI_VARIABLE_RUNTIME_ACCESS - | READ_ONLY, + | EFI_VARIABLE_READ_ONLY, sizeof(efi_vendor_keys), &efi_vendor_keys, false); @@ -1106,36 +1057,6 @@ err: return ret; }
-/** - * efi_set_variable() - set value of a UEFI variable - * - * This function implements the SetVariable runtime service. - * - * See the Unified Extensible Firmware Interface (UEFI) specification for - * details. - * - * @variable_name: name of the variable - * @vendor: vendor GUID - * @attributes: attributes of the variable - * @data_size: size of the buffer with the variable value - * @data: buffer with the variable value - * Return: status code - */ -efi_status_t EFIAPI efi_set_variable(u16 *variable_name, - const efi_guid_t *vendor, u32 attributes, - efi_uintn_t data_size, const void *data) -{ - EFI_ENTRY(""%ls" %pUl %x %zu %p", variable_name, vendor, attributes, - data_size, data); - - /* READ_ONLY bit is not part of API */ - attributes &= ~(u32)READ_ONLY; - - return EFI_EXIT(efi_set_variable_common(variable_name, vendor, - attributes, data_size, data, - true)); -} - /** * efi_query_variable_info() - get information about EFI variables * diff --git a/lib/efi_loader/efi_variable_tee.c b/lib/efi_loader/efi_variable_tee.c index 1d127720cd..1d6d4fe807 100644 --- a/lib/efi_loader/efi_variable_tee.c +++ b/lib/efi_loader/efi_variable_tee.c @@ -10,6 +10,7 @@ #include <efi.h> #include <efi_api.h> #include <efi_loader.h> +#include <efi_variable.h> #include <tee.h> #include <malloc.h> #include <mm_communication.h> @@ -243,24 +244,9 @@ out: return ret; }
-/** - * efi_get_variable() - retrieve value of a UEFI variable - * - * This function implements the GetVariable runtime service. - * - * See the Unified Extensible Firmware Interface (UEFI) specification for - * details. - * - * @name: name of the variable - * @guid: vendor GUID - * @attr: 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 EFIAPI efi_get_variable(u16 *name, const efi_guid_t *guid, - u32 *attr, efi_uintn_t *data_size, - void *data) +efi_status_t efi_get_variable_int(u16 *variable_name, const efi_guid_t *vendor, + u32 *attributes, efi_uintn_t *data_size, + void *data, u64 *timep) { struct smm_variable_access *var_acc; efi_uintn_t payload_size; @@ -269,15 +255,13 @@ efi_status_t EFIAPI efi_get_variable(u16 *name, const efi_guid_t *guid, u8 *comm_buf = NULL; efi_status_t ret;
- EFI_ENTRY(""%ls" %pUl %p %p %p", name, guid, attr, data_size, data); - - if (!name || !guid || !data_size) { + if (!variable_name || !vendor || !data_size) { ret = EFI_INVALID_PARAMETER; goto out; }
/* Check payload size */ - name_size = u16_strsize(name); + name_size = u16_strsize(variable_name); if (name_size > max_payload_size - MM_VARIABLE_ACCESS_HEADER_SIZE) { ret = EFI_INVALID_PARAMETER; goto out; @@ -300,11 +284,11 @@ efi_status_t EFIAPI efi_get_variable(u16 *name, const efi_guid_t *guid, goto out;
/* Fill in contents */ - guidcpy(&var_acc->guid, guid); + guidcpy(&var_acc->guid, vendor); var_acc->data_size = tmp_dsize; var_acc->name_size = name_size; - var_acc->attr = attr ? *attr : 0; - memcpy(var_acc->name, name, name_size); + var_acc->attr = attributes ? *attributes : 0; + memcpy(var_acc->name, variable_name, name_size);
/* Communicate */ ret = mm_communicate(comm_buf, payload_size); @@ -315,8 +299,8 @@ efi_status_t EFIAPI efi_get_variable(u16 *name, const efi_guid_t *guid, if (ret != EFI_SUCCESS) goto out;
- if (attr) - *attr = var_acc->attr; + if (attributes) + *attributes = var_acc->attr; if (data) memcpy(data, (u8 *)var_acc->name + var_acc->name_size, var_acc->data_size); @@ -325,7 +309,7 @@ efi_status_t EFIAPI efi_get_variable(u16 *name, const efi_guid_t *guid,
out: free(comm_buf); - return EFI_EXIT(ret); + return ret; }
/** @@ -415,24 +399,9 @@ out: return EFI_EXIT(ret); }
-/** - * efi_set_variable() - set value of a UEFI variable - * - * This function implements the SetVariable runtime service. - * - * See the Unified Extensible Firmware Interface (UEFI) specification for - * details. - * - * @name: name of the variable - * @guid: vendor GUID - * @attr: attributes of the variable - * @data_size: size of the buffer with the variable value - * @data: buffer with the variable value - * Return: status code - */ -efi_status_t EFIAPI efi_set_variable(u16 *name, const efi_guid_t *guid, - u32 attr, efi_uintn_t data_size, - const void *data) +efi_status_t efi_set_variable_int(u16 *variable_name, const efi_guid_t *vendor, + u32 attributes, efi_uintn_t data_size, + const void *data, bool ro_check) { struct smm_variable_access *var_acc; efi_uintn_t payload_size; @@ -440,9 +409,7 @@ efi_status_t EFIAPI efi_set_variable(u16 *name, const efi_guid_t *guid, u8 *comm_buf = NULL; efi_status_t ret;
- EFI_ENTRY(""%ls" %pUl %x %zu %p", name, guid, attr, data_size, data); - - if (!name || name[0] == 0 || !guid) { + if (!variable_name || variable_name[0] == 0 || !vendor) { ret = EFI_INVALID_PARAMETER; goto out; } @@ -452,7 +419,7 @@ efi_status_t EFIAPI efi_set_variable(u16 *name, const efi_guid_t *guid, }
/* Check payload size */ - name_size = u16_strsize(name); + name_size = u16_strsize(variable_name); payload_size = MM_VARIABLE_ACCESS_HEADER_SIZE + name_size + data_size; if (payload_size > max_payload_size) { ret = EFI_INVALID_PARAMETER; @@ -466,11 +433,11 @@ efi_status_t EFIAPI efi_set_variable(u16 *name, const efi_guid_t *guid, goto out;
/* Fill in contents */ - guidcpy(&var_acc->guid, guid); + guidcpy(&var_acc->guid, vendor); var_acc->data_size = data_size; var_acc->name_size = name_size; - var_acc->attr = attr; - memcpy(var_acc->name, name, name_size); + var_acc->attr = attributes; + memcpy(var_acc->name, variable_name, name_size); memcpy((u8 *)var_acc->name + name_size, data, data_size);
/* Communicate */ @@ -478,7 +445,7 @@ efi_status_t EFIAPI efi_set_variable(u16 *name, const efi_guid_t *guid,
out: free(comm_buf); - return EFI_EXIT(ret); + return ret; }
/** -- 2.27.0