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u-boot-brain/lib/efi_loader/efi_variable.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* UEFI runtime variable services
*
* Copyright (c) 2017 Rob Clark
*/
#include <common.h>
#include <efi_loader.h>
#include <env_internal.h>
#include <hexdump.h>
#include <malloc.h>
#include <rtc.h>
#include <search.h>
#include <crypto/pkcs7_parser.h>
#include <linux/compat.h>
#include <u-boot/crc.h>
enum efi_secure_mode {
EFI_MODE_SETUP,
EFI_MODE_USER,
EFI_MODE_AUDIT,
EFI_MODE_DEPLOYED,
};
const efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_GUID;
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:
*
* efi_$guid_$varname = {attributes}(type)value
*
* For example:
*
* efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_OsIndicationsSupported=
* "{ro,boot,run}(blob)0000000000000000"
* efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_BootOrder=
* "(blob)00010000"
*
* The attributes are a comma separated list of these possible
* attributes:
*
* + ro - read-only
* + boot - boot-services access
* + run - runtime access
*
* NOTE: with current implementation, no variables are available after
* ExitBootServices, and all are persisted (if possible).
*
* If not specified, the attributes default to "{boot}".
*
* The required type is one of:
*
* + utf8 - raw utf8 string
* + blob - arbitrary length hex string
*
* Maybe a utf16 type would be useful to for a string value to be auto
* converted to utf16?
*/
#define PREFIX_LEN (strlen("efi_xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx_"))
/**
* efi_to_native() - convert the UEFI variable name and vendor GUID to U-Boot
* variable name
*
* The U-Boot variable name is a concatenation of prefix 'efi', the hexstring
* encoded vendor GUID, and the UTF-8 encoded UEFI variable name separated by
* underscores, e.g. 'efi_8be4df61-93ca-11d2-aa0d-00e098032b8c_BootOrder'.
*
* @native: pointer to pointer to U-Boot variable name
* @variable_name: UEFI variable name
* @vendor: vendor GUID
* Return: status code
*/
static efi_status_t efi_to_native(char **native, const u16 *variable_name,
const efi_guid_t *vendor)
{
size_t len;
char *pos;
len = PREFIX_LEN + utf16_utf8_strlen(variable_name) + 1;
*native = malloc(len);
if (!*native)
return EFI_OUT_OF_RESOURCES;
pos = *native;
pos += sprintf(pos, "efi_%pUl_", vendor);
utf16_utf8_strcpy(&pos, variable_name);
return EFI_SUCCESS;
}
/**
* prefix() - skip over prefix
*
* Skip over a prefix string.
*
* @str: string with prefix
* @prefix: prefix string
* Return: string without prefix, or NULL if prefix not found
*/
static const char *prefix(const char *str, const char *prefix)
{
size_t n = strlen(prefix);
if (!strncmp(prefix, str, n))
return str + n;
return NULL;
}
/**
* parse_attr() - decode attributes part of variable value
*
* Convert the string encoded attributes of a UEFI variable to a bit mask.
* TODO: Several attributes are not supported.
*
* @str: value of U-Boot variable
* @attrp: pointer to UEFI attributes
* @timep: pointer to time attribute
* Return: pointer to remainder of U-Boot variable value
*/
static const char *parse_attr(const char *str, u32 *attrp, u64 *timep)
{
u32 attr = 0;
char sep = '{';
if (*str != '{') {
*attrp = EFI_VARIABLE_BOOTSERVICE_ACCESS;
return str;
}
while (*str == sep) {
const char *s;
str++;
if ((s = prefix(str, "ro"))) {
attr |= READ_ONLY;
} else if ((s = prefix(str, "nv"))) {
attr |= EFI_VARIABLE_NON_VOLATILE;
} else if ((s = prefix(str, "boot"))) {
attr |= EFI_VARIABLE_BOOTSERVICE_ACCESS;
} else if ((s = prefix(str, "run"))) {
attr |= EFI_VARIABLE_RUNTIME_ACCESS;
} else if ((s = prefix(str, "time="))) {
attr |= EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS;
hex2bin((u8 *)timep, s, sizeof(*timep));
s += sizeof(*timep) * 2;
} else if (*str == '}') {
break;
} else {
printf("invalid attribute: %s\n", str);
break;
}
str = s;
sep = ',';
}
str++;
*attrp = attr;
return str;
}
/**
* efi_set_secure_state - modify secure boot state variables
* @sec_boot: value of SecureBoot
* @setup_mode: value of SetupMode
* @audit_mode: value of AuditMode
* @deployed_mode: value of DeployedMode
*
* Modify secure boot stat-related variables as indicated.
*
* Return: status code
*/
static efi_status_t efi_set_secure_state(int sec_boot, int setup_mode,
int audit_mode, int deployed_mode)
{
u32 attributes;
efi_status_t ret;
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);
if (ret != EFI_SUCCESS)
goto err;
ret = efi_set_variable_common(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);
if (ret != EFI_SUCCESS)
goto err;
ret = efi_set_variable_common(L"DeployedMode",
&efi_global_variable_guid, attributes,
sizeof(deployed_mode), &deployed_mode,
false);
err:
return ret;
}
/**
* efi_transfer_secure_state - handle a secure boot state transition
* @mode: new state
*
* Depending on @mode, secure boot related variables are updated.
* Those variables are *read-only* for users, efi_set_variable_common()
* is called here.
*
* Return: status code
*/
static efi_status_t efi_transfer_secure_state(enum efi_secure_mode mode)
{
efi_status_t ret;
debug("Switching secure state from %d to %d\n", efi_secure_mode, mode);
if (mode == EFI_MODE_DEPLOYED) {
ret = efi_set_secure_state(1, 0, 0, 1);
if (ret != EFI_SUCCESS)
goto err;
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);
if (ret != EFI_SUCCESS)
goto err;
ret = efi_set_secure_state(0, 1, 1, 0);
if (ret != EFI_SUCCESS)
goto err;
efi_secure_boot = true;
} else if (mode == EFI_MODE_USER) {
ret = efi_set_secure_state(1, 0, 0, 0);
if (ret != EFI_SUCCESS)
goto err;
efi_secure_boot = true;
} else if (mode == EFI_MODE_SETUP) {
ret = efi_set_secure_state(0, 1, 0, 0);
if (ret != EFI_SUCCESS)
goto err;
} else {
return EFI_INVALID_PARAMETER;
}
efi_secure_mode = mode;
return EFI_SUCCESS;
err:
/* TODO: What action should be taken here? */
printf("ERROR: Secure state transition failed\n");
return ret;
}
/**
* efi_init_secure_state - initialize secure boot state
*
* Return: status code
*/
static efi_status_t efi_init_secure_state(void)
{
enum efi_secure_mode mode;
efi_uintn_t size;
efi_status_t ret;
/*
* TODO:
* Since there is currently no "platform-specific" installation
* method of Platform Key, we can't say if VendorKeys is 0 or 1
* precisely.
*/
size = 0;
ret = efi_get_variable_common(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;
else
mode = EFI_MODE_SETUP;
efi_vendor_keys = 0;
} else if (ret == EFI_NOT_FOUND) {
mode = EFI_MODE_SETUP;
efi_vendor_keys = 1;
} else {
goto err;
}
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);
err:
return ret;
}
/**
* efi_secure_boot_enabled - return if secure boot is enabled or not
*
* Return: true if enabled, false if disabled
*/
bool efi_secure_boot_enabled(void)
{
return efi_secure_boot;
}
#ifdef CONFIG_EFI_SECURE_BOOT
static u8 pkcs7_hdr[] = {
/* SEQUENCE */
0x30, 0x82, 0x05, 0xc7,
/* OID: pkcs7-signedData */
0x06, 0x09, 0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x01, 0x07, 0x02,
/* Context Structured? */
0xa0, 0x82, 0x05, 0xb8,
};
/**
* efi_variable_parse_signature - parse a signature in variable
* @buf: Pointer to variable's value
* @buflen: Length of @buf
*
* Parse a signature embedded in variable's value and instantiate
* a pkcs7_message structure. Since pkcs7_parse_message() accepts only
* pkcs7's signedData, some header needed be prepended for correctly
* parsing authentication data, particularly for variable's.
*
* Return: Pointer to pkcs7_message structure on success, NULL on error
*/
static struct pkcs7_message *efi_variable_parse_signature(const void *buf,
size_t buflen)
{
u8 *ebuf;
size_t ebuflen, len;
struct pkcs7_message *msg;
/*
* This is the best assumption to check if the binary is
* already in a form of pkcs7's signedData.
*/
if (buflen > sizeof(pkcs7_hdr) &&
!memcmp(&((u8 *)buf)[4], &pkcs7_hdr[4], 11)) {
msg = pkcs7_parse_message(buf, buflen);
goto out;
}
/*
* Otherwise, we should add a dummy prefix sequence for pkcs7
* message parser to be able to process.
* NOTE: EDK2 also uses similar hack in WrapPkcs7Data()
* in CryptoPkg/Library/BaseCryptLib/Pk/CryptPkcs7VerifyCommon.c
* TODO:
* The header should be composed in a more refined manner.
*/
debug("Makeshift prefix added to authentication data\n");
ebuflen = sizeof(pkcs7_hdr) + buflen;
if (ebuflen <= 0x7f) {
debug("Data is too short\n");
return NULL;
}
ebuf = malloc(ebuflen);
if (!ebuf) {
debug("Out of memory\n");
return NULL;
}
memcpy(ebuf, pkcs7_hdr, sizeof(pkcs7_hdr));
memcpy(ebuf + sizeof(pkcs7_hdr), buf, buflen);
len = ebuflen - 4;
ebuf[2] = (len >> 8) & 0xff;
ebuf[3] = len & 0xff;
len = ebuflen - 0x13;
ebuf[0x11] = (len >> 8) & 0xff;
ebuf[0x12] = len & 0xff;
msg = pkcs7_parse_message(ebuf, ebuflen);
free(ebuf);
out:
if (IS_ERR(msg))
return NULL;
return msg;
}
/**
* efi_variable_authenticate - authenticate a variable
* @variable: Variable name in u16
* @vendor: Guid of variable
* @data_size: Size of @data
* @data: Pointer to variable's value
* @given_attr: Attributes to be given at SetVariable()
* @env_attr: Attributes that an existing variable holds
* @time: signed time that an existing variable holds
*
* Called by efi_set_variable() to verify that the input is correct.
* Will replace the given data pointer with another that points to
* the actual data to store in the internal memory.
* On success, @data and @data_size will be replaced with variable's
* actual data, excluding authentication data, and its size, and variable's
* attributes and signed time will also be returned in @env_attr and @time,
* respectively.
*
* Return: status code
*/
static efi_status_t efi_variable_authenticate(u16 *variable,
const efi_guid_t *vendor,
efi_uintn_t *data_size,
const void **data, u32 given_attr,
u32 *env_attr, u64 *time)
{
const struct efi_variable_authentication_2 *auth;
struct efi_signature_store *truststore, *truststore2;
struct pkcs7_message *var_sig;
struct efi_image_regions *regs;
struct efi_time timestamp;
struct rtc_time tm;
u64 new_time;
efi_status_t ret;
var_sig = NULL;
truststore = NULL;
truststore2 = NULL;
regs = NULL;
ret = EFI_SECURITY_VIOLATION;
if (*data_size < sizeof(struct efi_variable_authentication_2))
goto err;
/* authentication data */
auth = *data;
if (*data_size < (sizeof(auth->time_stamp)
+ auth->auth_info.hdr.dwLength))
goto err;
if (guidcmp(&auth->auth_info.cert_type, &efi_guid_cert_type_pkcs7))
goto err;
*data += sizeof(auth->time_stamp) + auth->auth_info.hdr.dwLength;
*data_size -= (sizeof(auth->time_stamp)
+ auth->auth_info.hdr.dwLength);
memcpy(&timestamp, &auth->time_stamp, sizeof(timestamp));
memset(&tm, 0, sizeof(tm));
tm.tm_year = timestamp.year;
tm.tm_mon = timestamp.month;
tm.tm_mday = timestamp.day;
tm.tm_hour = timestamp.hour;
tm.tm_min = timestamp.minute;
tm.tm_sec = timestamp.second;
new_time = rtc_mktime(&tm);
if (!efi_secure_boot_enabled()) {
/* finished checking */
*time = new_time;
return EFI_SUCCESS;
}
if (new_time <= *time)
goto err;
/* data to be digested */
regs = calloc(sizeof(*regs) + sizeof(struct image_region) * 5, 1);
if (!regs)
goto err;
regs->max = 5;
efi_image_region_add(regs, (uint8_t *)variable,
(uint8_t *)variable
+ u16_strlen(variable) * sizeof(u16), 1);
efi_image_region_add(regs, (uint8_t *)vendor,
(uint8_t *)vendor + sizeof(*vendor), 1);
efi_image_region_add(regs, (uint8_t *)&given_attr,
(uint8_t *)&given_attr + sizeof(given_attr), 1);
efi_image_region_add(regs, (uint8_t *)&timestamp,
(uint8_t *)&timestamp + sizeof(timestamp), 1);
efi_image_region_add(regs, (uint8_t *)*data,
(uint8_t *)*data + *data_size, 1);
/* variable's signature list */
if (auth->auth_info.hdr.dwLength < sizeof(auth->auth_info))
goto err;
var_sig = efi_variable_parse_signature(auth->auth_info.cert_data,
auth->auth_info.hdr.dwLength
- sizeof(auth->auth_info));
if (!var_sig) {
debug("Parsing variable's signature failed\n");
goto err;
}
/* signature database used for authentication */
if (u16_strcmp(variable, L"PK") == 0 ||
u16_strcmp(variable, L"KEK") == 0) {
/* with PK */
truststore = efi_sigstore_parse_sigdb(L"PK");
if (!truststore)
goto err;
} else if (u16_strcmp(variable, L"db") == 0 ||
u16_strcmp(variable, L"dbx") == 0) {
/* with PK and KEK */
truststore = efi_sigstore_parse_sigdb(L"KEK");
truststore2 = efi_sigstore_parse_sigdb(L"PK");
if (!truststore) {
if (!truststore2)
goto err;
truststore = truststore2;
truststore2 = NULL;
}
} else {
/* TODO: support private authenticated variables */
goto err;
}
/* verify signature */
if (efi_signature_verify_with_sigdb(regs, var_sig, truststore, NULL)) {
debug("Verified\n");
} else {
if (truststore2 &&
efi_signature_verify_with_sigdb(regs, var_sig,
truststore2, NULL)) {
debug("Verified\n");
} else {
debug("Verifying variable's signature failed\n");
goto err;
}
}
/* finished checking */
*time = rtc_mktime(&tm);
ret = EFI_SUCCESS;
err:
efi_sigstore_free(truststore);
efi_sigstore_free(truststore2);
pkcs7_free_message(var_sig);
free(regs);
return ret;
}
#else
static efi_status_t efi_variable_authenticate(u16 *variable,
const efi_guid_t *vendor,
efi_uintn_t *data_size,
const void **data, u32 given_attr,
u32 *env_attr, u64 *time)
{
return EFI_SUCCESS;
}
#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)
{
char *native_name;
efi_status_t ret;
unsigned long in_size;
const char *val = NULL, *s;
u64 time = 0;
u32 attr;
if (!variable_name || !vendor || !data_size)
return EFI_EXIT(EFI_INVALID_PARAMETER);
ret = efi_to_native(&native_name, variable_name, vendor);
if (ret)
return ret;
EFI_PRINT("get '%s'\n", native_name);
val = env_get(native_name);
free(native_name);
if (!val)
return EFI_NOT_FOUND;
val = parse_attr(val, &attr, &time);
in_size = *data_size;
if ((s = prefix(val, "(blob)"))) {
size_t len = strlen(s);
/* number of hexadecimal digits must be even */
if (len & 1)
return EFI_DEVICE_ERROR;
/* two characters per byte: */
len /= 2;
*data_size = len;
if (in_size < len) {
ret = EFI_BUFFER_TOO_SMALL;
goto out;
}
if (!data) {
debug("Variable with no data shouldn't exist.\n");
return EFI_INVALID_PARAMETER;
}
if (hex2bin(data, s, len))
return EFI_DEVICE_ERROR;
EFI_PRINT("got value: \"%s\"\n", s);
} else if ((s = prefix(val, "(utf8)"))) {
unsigned len = strlen(s) + 1;
*data_size = len;
if (in_size < len) {
ret = EFI_BUFFER_TOO_SMALL;
goto out;
}
if (!data) {
debug("Variable with no data shouldn't exist.\n");
return EFI_INVALID_PARAMETER;
}
memcpy(data, s, len);
((char *)data)[len] = '\0';
EFI_PRINT("got value: \"%s\"\n", (char *)data);
} else {
EFI_PRINT("invalid value: '%s'\n", val);
return EFI_DEVICE_ERROR;
}
out:
if (attributes)
*attributes = attr & EFI_VARIABLE_MASK;
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;
/**
* parse_uboot_variable() - parse a u-boot variable and get uefi-related
* information
* @variable: whole data of u-boot variable (ie. name=value)
* @variable_name_size: size of variable_name buffer in byte
* @variable_name: name of uefi variable in u16, null-terminated
* @vendor: vendor's guid
* @attributes: attributes
*
* A uefi variable is encoded into a u-boot variable as described above.
* This function parses such a u-boot variable and retrieve uefi-related
* information into respective parameters. In return, variable_name_size
* is the size of variable name including NULL.
*
* Return: EFI_SUCCESS if parsing is OK, EFI_NOT_FOUND when
* the entire variable list has been returned,
* otherwise non-zero status code
*/
static efi_status_t parse_uboot_variable(char *variable,
efi_uintn_t *variable_name_size,
u16 *variable_name,
const efi_guid_t *vendor,
u32 *attributes)
{
char *guid, *name, *end, c;
size_t name_len;
efi_uintn_t old_variable_name_size;
u64 time;
u16 *p;
guid = strchr(variable, '_');
if (!guid)
return EFI_INVALID_PARAMETER;
guid++;
name = strchr(guid, '_');
if (!name)
return EFI_INVALID_PARAMETER;
name++;
end = strchr(name, '=');
if (!end)
return EFI_INVALID_PARAMETER;
name_len = end - name;
old_variable_name_size = *variable_name_size;
*variable_name_size = sizeof(u16) * (name_len + 1);
if (old_variable_name_size < *variable_name_size)
return EFI_BUFFER_TOO_SMALL;
end++; /* point to value */
/* variable name */
p = variable_name;
utf8_utf16_strncpy(&p, name, name_len);
variable_name[name_len] = 0;
/* guid */
c = *(name - 1);
*(name - 1) = '\0'; /* guid need be null-terminated here */
if (uuid_str_to_bin(guid, (unsigned char *)vendor,
UUID_STR_FORMAT_GUID))
/* The only error would be EINVAL. */
return EFI_INVALID_PARAMETER;
*(name - 1) = c;
/* attributes */
parse_attr(end, attributes, &time);
return EFI_SUCCESS;
}
/**
* efi_get_next_variable_name() - enumerate the current variable names
*
* @variable_name_size: size of variable_name buffer in byte
* @variable_name: name of uefi variable's name in u16
* @vendor: vendor's guid
*
* This function implements the GetNextVariableName service.
*
* See the Unified Extensible Firmware Interface (UEFI) specification for
* details.
*
* Return: status code
*/
efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size,
u16 *variable_name,
efi_guid_t *vendor)
{
char *native_name, *variable;
ssize_t name_len, list_len;
char regex[256];
char * const regexlist[] = {regex};
u32 attributes;
int i;
efi_status_t ret;
EFI_ENTRY("%p \"%ls\" %pUl", variable_name_size, variable_name, vendor);
if (!variable_name_size || !variable_name || !vendor)
return EFI_EXIT(EFI_INVALID_PARAMETER);
if (variable_name[0]) {
/* check null-terminated string */
for (i = 0; i < *variable_name_size; i++)
if (!variable_name[i])
break;
if (i >= *variable_name_size)
return EFI_EXIT(EFI_INVALID_PARAMETER);
/* search for the last-returned variable */
ret = efi_to_native(&native_name, variable_name, vendor);
if (ret)
return EFI_EXIT(ret);
name_len = strlen(native_name);
for (variable = efi_variables_list; variable && *variable;) {
if (!strncmp(variable, native_name, name_len) &&
variable[name_len] == '=')
break;
variable = strchr(variable, '\n');
if (variable)
variable++;
}
free(native_name);
if (!(variable && *variable))
return EFI_EXIT(EFI_INVALID_PARAMETER);
/* next variable */
variable = strchr(variable, '\n');
if (variable)
variable++;
if (!(variable && *variable))
return EFI_EXIT(EFI_NOT_FOUND);
} else {
/*
*new search: free a list used in the previous search
*/
free(efi_variables_list);
efi_variables_list = NULL;
efi_cur_variable = NULL;
snprintf(regex, 256, "efi_.*-.*-.*-.*-.*_.*");
list_len = hexport_r(&env_htab, '\n',
H_MATCH_REGEX | H_MATCH_KEY,
&efi_variables_list, 0, 1, regexlist);
if (list_len <= 1)
return EFI_EXIT(EFI_NOT_FOUND);
variable = efi_variables_list;
}
ret = parse_uboot_variable(variable, variable_name_size, variable_name,
vendor, &attributes);
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)
{
char *native_name = NULL, *old_data = NULL, *val = NULL, *s;
efi_uintn_t old_size;
bool append, delete;
u64 time = 0;
u32 attr;
efi_status_t ret = EFI_SUCCESS;
debug("%s: set '%s'\n", __func__, native_name);
if (!variable_name || !*variable_name || !vendor ||
((attributes & EFI_VARIABLE_RUNTIME_ACCESS) &&
!(attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS))) {
ret = EFI_INVALID_PARAMETER;
goto err;
}
ret = efi_to_native(&native_name, variable_name, vendor);
if (ret)
goto err;
/* check if a variable exists */
old_size = 0;
attr = 0;
ret = efi_get_variable_common(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)) {
ret = EFI_WRITE_PROTECTED;
goto err;
}
/* attributes won't be changed */
if (!delete &&
((ro_check && attr != attributes) ||
(!ro_check && ((attr & ~(u32)READ_ONLY)
!= (attributes & ~(u32)READ_ONLY))))) {
ret = EFI_INVALID_PARAMETER;
goto err;
}
} else {
if (delete || append) {
/*
* Trying to delete or to update a non-existent
* variable.
*/
ret = EFI_NOT_FOUND;
goto err;
}
}
if (((!u16_strcmp(variable_name, L"PK") ||
!u16_strcmp(variable_name, L"KEK")) &&
!guidcmp(vendor, &efi_global_variable_guid)) ||
((!u16_strcmp(variable_name, L"db") ||
!u16_strcmp(variable_name, L"dbx")) &&
!guidcmp(vendor, &efi_guid_image_security_database))) {
/* authentication is mandatory */
if (!(attributes &
EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)) {
debug("%ls: AUTHENTICATED_WRITE_ACCESS required\n",
variable_name);
ret = EFI_INVALID_PARAMETER;
goto err;
}
}
/* authenticate a variable */
if (IS_ENABLED(CONFIG_EFI_SECURE_BOOT)) {
if (attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) {
ret = EFI_INVALID_PARAMETER;
goto err;
}
if (attributes &
EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) {
ret = efi_variable_authenticate(variable_name, vendor,
&data_size, &data,
attributes, &attr,
&time);
if (ret != EFI_SUCCESS)
goto err;
/* last chance to check for delete */
if (!data_size)
delete = true;
}
} else {
if (attributes &
(EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS |
EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)) {
debug("Secure boot is not configured\n");
ret = EFI_INVALID_PARAMETER;
goto err;
}
}
/* delete a variable */
if (delete) {
/* !old_size case has been handled before */
val = NULL;
ret = EFI_SUCCESS;
goto out;
}
if (append) {
old_data = malloc(old_size);
if (!old_data) {
ret = EFI_OUT_OF_RESOURCES;
goto err;
}
ret = efi_get_variable_common(variable_name, vendor,
&attr, &old_size, old_data);
if (ret != EFI_SUCCESS)
goto err;
} else {
old_size = 0;
}
val = malloc(2 * old_size + 2 * data_size
+ strlen("{ro,run,boot,nv,time=0123456701234567}(blob)")
+ 1);
if (!val) {
ret = EFI_OUT_OF_RESOURCES;
goto err;
}
s = val;
/*
* store attributes
*/
attributes &= (READ_ONLY |
EFI_VARIABLE_NON_VOLATILE |
EFI_VARIABLE_BOOTSERVICE_ACCESS |
EFI_VARIABLE_RUNTIME_ACCESS |
EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS);
s += sprintf(s, "{");
while (attributes) {
attr = 1 << (ffs(attributes) - 1);
if (attr == READ_ONLY) {
s += sprintf(s, "ro");
} else if (attr == EFI_VARIABLE_NON_VOLATILE) {
s += sprintf(s, "nv");
} else if (attr == EFI_VARIABLE_BOOTSERVICE_ACCESS) {
s += sprintf(s, "boot");
} else if (attr == EFI_VARIABLE_RUNTIME_ACCESS) {
s += sprintf(s, "run");
} else if (attr ==
EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) {
s += sprintf(s, "time=");
s = bin2hex(s, (u8 *)&time, sizeof(time));
}
attributes &= ~attr;
if (attributes)
s += sprintf(s, ",");
}
s += sprintf(s, "}");
s += sprintf(s, "(blob)");
/* store payload: */
if (append)
s = bin2hex(s, old_data, old_size);
s = bin2hex(s, data, data_size);
*s = '\0';
EFI_PRINT("setting: %s=%s\n", native_name, val);
out:
if (env_set(native_name, val)) {
ret = EFI_DEVICE_ERROR;
} else {
bool vendor_keys_modified = false;
if ((u16_strcmp(variable_name, L"PK") == 0 &&
guidcmp(vendor, &efi_global_variable_guid) == 0)) {
ret = efi_transfer_secure_state(
(delete ? EFI_MODE_SETUP :
EFI_MODE_USER));
if (ret != EFI_SUCCESS)
goto err;
if (efi_secure_mode != EFI_MODE_SETUP)
vendor_keys_modified = true;
} else if ((u16_strcmp(variable_name, L"KEK") == 0 &&
guidcmp(vendor, &efi_global_variable_guid) == 0)) {
if (efi_secure_mode != EFI_MODE_SETUP)
vendor_keys_modified = true;
}
/* update VendorKeys */
if (vendor_keys_modified & efi_vendor_keys) {
efi_vendor_keys = 0;
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);
} else {
ret = EFI_SUCCESS;
}
}
err:
free(native_name);
free(old_data);
free(val);
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
*
* This function implements the QueryVariableInfo() runtime service.
*
* See the Unified Extensible Firmware Interface (UEFI) specification for
* details.
*
* @attributes: bitmask to select variables to be
* queried
* @maximum_variable_storage_size: maximum size of storage area for the
* selected variable types
* @remaining_variable_storage_size: remaining size of storage are for the
* selected variable types
* @maximum_variable_size: maximum size of a variable of the
* selected type
* Returns: status code
*/
efi_status_t __efi_runtime EFIAPI efi_query_variable_info(
u32 attributes,
u64 *maximum_variable_storage_size,
u64 *remaining_variable_storage_size,
u64 *maximum_variable_size)
{
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)
{
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
* @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_UNSUPPORTED;
}
/**
* efi_set_variable_runtime() - runtime implementation of SetVariable()
*
* @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
*/
static efi_status_t __efi_runtime EFIAPI
efi_set_variable_runtime(u16 *variable_name, const efi_guid_t *vendor,
u32 attributes, efi_uintn_t data_size,
const void *data)
{
return EFI_UNSUPPORTED;
}
/**
* efi_variables_boot_exit_notify() - notify ExitBootServices() is called
*/
void efi_variables_boot_exit_notify(void)
{
efi_runtime_services.get_variable = efi_get_variable_runtime;
efi_runtime_services.get_next_variable_name =
efi_get_next_variable_name_runtime;
efi_runtime_services.set_variable = efi_set_variable_runtime;
efi_update_table_header_crc32(&efi_runtime_services.hdr);
}
/**
* efi_init_variables() - initialize variable services
*
* Return: status code
*/
efi_status_t efi_init_variables(void)
{
efi_status_t ret;
ret = efi_init_secure_state();
return ret;
}
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