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.

Signed-off-by: Heinrich Schuchardt xypron.glpk@gmx.de --- v2: add missing efi_variable.h consider attributes==NULL in efi_variable_get() --- include/efi_variable.h | 40 +++++++ lib/efi_loader/Makefile | 1 + lib/efi_loader/efi_variable.c | 171 ++++++++------------------- lib/efi_loader/efi_variable_common.c | 79 +++++++++++++ lib/efi_loader/efi_variable_tee.c | 75 ++++-------- 5 files changed, 188 insertions(+), 178 deletions(-) create mode 100644 include/efi_variable.h create mode 100644 lib/efi_loader/efi_variable_common.c

diff --git a/include/efi_variable.h b/include/efi_variable.h new file mode 100644 index 0000000000..784dbd9cf4 --- /dev/null +++ b/include/efi_variable.h @@ -0,0 +1,40 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * Copyright (c) 2020, Heinrich Schuchardt xypron.glpk@gmx.de + */ + +#ifndef _EFI_VARIABLE_H +#define _EFI_VARIABLE_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 + * 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); + +/** + * 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..16b93ef7f0 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-$(CONFIG_EFI_UNICODE_COLLATION_PROTOCOL2) += efi_unicode_collation.o +obj-y += efi_variable_common.o ifeq ($(CONFIG_EFI_MM_COMM_TEE),y) obj-y += efi_variable_tee.o else diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c index e097670e28..85df1427bc 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>

@@ -30,20 +30,6 @@ static bool efi_secure_boot; static int 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); - -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: * @@ -154,7 +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"))) { @@ -202,29 +188,29 @@ static efi_status_t efi_set_secure_state(int sec_boot, int 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(sec_boot), &sec_boot, - false); + EFI_VARIABLE_READ_ONLY; + ret = efi_set_variable_int(L"SecureBoot", &efi_global_variable_guid, + attributes, sizeof(sec_boot), &sec_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; } @@ -234,7 +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 @@ -252,10 +238,10 @@ 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;

@@ -307,8 +293,8 @@ 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); + ret = efi_get_variable_int(L"PK", &efi_global_variable_guid, + NULL, &size, NULL); if (ret == EFI_BUFFER_TOO_SMALL) { if (IS_ENABLED(CONFIG_EFI_SECURE_BOOT)) mode = EFI_MODE_USER; @@ -325,13 +311,13 @@ 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; @@ -593,10 +579,9 @@ 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) +efi_status_t efi_get_variable_int(u16 *variable_name, const efi_guid_t *vendor, + u32 *attributes, efi_uintn_t *data_size, + void *data) { char *native_name; efi_status_t ret; @@ -679,35 +664,6 @@ out: 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); - return EFI_EXIT(ret); -} - static char *efi_variables_list; static char *efi_cur_variable;

@@ -871,12 +827,9 @@ 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; @@ -899,15 +852,15 @@ 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); + ret = efi_get_variable_int(variable_name, vendor, &attr, + &old_size, NULL); 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; } @@ -915,8 +868,8 @@ 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; } @@ -990,8 +943,8 @@ 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); + ret = efi_get_variable_int(variable_name, vendor, + &attr, &old_size, old_data); if (ret != EFI_SUCCESS) goto err; } else { @@ -1011,7 +964,7 @@ 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 | @@ -1020,7 +973,7 @@ 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"); @@ -1074,12 +1027,12 @@ 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); @@ -1096,36 +1049,6 @@ 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_common.c b/lib/efi_loader/efi_variable_common.c new file mode 100644 index 0000000000..e6a39fceac --- /dev/null +++ b/lib/efi_loader/efi_variable_common.c @@ -0,0 +1,79 @@ +// 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> +#include <linux/bitops.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); + + /* 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_tee.c b/lib/efi_loader/efi_variable_tee.c index cacc76e23d..2513878c82 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) { 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; }

/** @@ -417,24 +401,9 @@ 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; @@ -442,9 +411,7 @@ 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; } @@ -454,7 +421,7 @@ 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; @@ -468,11 +435,11 @@ 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 */ @@ -480,7 +447,7 @@ 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