[U-Boot] [PATCH 07/16] efi_loader: variable: support variable authentication

Heinrich Schuchardt
2019-11-16T20:02:45Z

On 11/13/19 1:52 AM, AKASHI Takahiro wrote:
> With this commit, EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS
> is supported for authenticated variables and the system secure state
> will transfer between setup mode and user mode as UEFI specification
> section 32.3 describes.
>
> Internally, authentication data is stored as part of authenticated
> variable's value. It is nothing but a pkcs7 message (but we need some
> wrapper, see efi_variable_parse_signature()) and will be validated by
> efi_variable_authenticate(), hence efi_signature_verify_with_db().
>
> Associated time value will be encoded in "{...,time=...}" along with
> other UEFI variable's attributes.

Please, provide a unit test testing this single feature.

Best regards

Heinrich

>
> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org>
> ---
> include/efi_loader.h | 3 +
> lib/efi_loader/efi_variable.c | 664 ++++++++++++++++++++++++++++------
> 2 files changed, 563 insertions(+), 104 deletions(-)
>
> diff --git a/include/efi_loader.h b/include/efi_loader.h
> index 92b683b7653a..2922ee5089a8 100644
> --- a/include/efi_loader.h
> +++ b/include/efi_loader.h
> @@ -175,6 +175,7 @@ extern const efi_guid_t efi_guid_image_security_database;
> extern const efi_guid_t efi_guid_sha256;
> extern const efi_guid_t efi_guid_cert_x509;
> extern const efi_guid_t efi_guid_cert_x509_sha256;
> +extern const efi_guid_t efi_guid_cert_type_pkcs7;
>
> extern unsigned int __efi_runtime_start, __efi_runtime_stop;
> extern unsigned int __efi_runtime_rel_start, __efi_runtime_rel_stop;
> @@ -697,6 +698,8 @@ efi_status_t efi_image_region_add(struct efi_image_regions *regs,
>
> void efi_sigstore_free(struct efi_signature_store *sigstore);
> struct efi_signature_store *efi_sigstore_parse_sigdb(u16 *name);
> +
> +bool efi_secure_boot_enabled(void);
> #endif /* CONFIG_EFI_SECURE_BOOT */
>
> #else /* CONFIG_IS_ENABLED(EFI_LOADER) */
> diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
> index 46f35bc60ba0..7e7db8e4a10d 100644
> --- a/lib/efi_loader/efi_variable.c
> +++ b/lib/efi_loader/efi_variable.c
> @@ -10,7 +10,13 @@
> #include <env_internal.h>
> #include <hexdump.h>
> #include <malloc.h>
> +#include <rtc.h>
> #include <search.h>
> +#include <linux/compat.h>
> +#include "../lib/crypto/pkcs7_parser.h"
> +
> +const efi_guid_t efi_guid_cert_type_pkcs7 = EFI_CERT_TYPE_PKCS7_GUID;
> +static bool efi_secure_boot;
>
> #define READ_ONLY BIT(31)
>
> @@ -107,7 +113,7 @@ static const char *prefix(const char *str, const char *prefix)
> * @attrp: pointer to UEFI attributes
> * Return: pointer to remainder of U-Boot variable value
> */
> -static const char *parse_attr(const char *str, u32 *attrp)
> +static const char *parse_attr(const char *str, u32 *attrp, u64 *timep)
> {
> u32 attr = 0;
> char sep = '{';
> @@ -130,6 +136,12 @@ static const char *parse_attr(const char *str, u32 *attrp)
> 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;
> @@ -147,48 +159,290 @@ static const char *parse_attr(const char *str, u32 *attrp)
> }
>
> /**
> - * efi_get_variable() - retrieve value of a UEFI variable
> + * efi_secure_boot_enabled - return if secure boot is enabled or not
> *
> - * This function implements the GetVariable runtime service.
> + * 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
> *
> - * See the Unified Extensible Firmware Interface (UEFI) specification for
> - * details.
> + * 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.
> *
> - * @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
> + * Return: Pointer to pkcs7_message structure on success, NULL on error
> */
> -efi_status_t EFIAPI efi_get_variable(u16 *variable_name,
> - const efi_guid_t *vendor, u32 *attributes,
> - efi_uintn_t *data_size, void *data)
> +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: EFI_SUCCESS on success, status code (negative) on error
> + */
> +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;
> + const 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);
> +
> + timestamp = &auth->time_stamp;
> + 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(1, sizeof(*regs));
> + if (!regs)
> + goto err;
> + 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 (IS_ERR(var_sig)) {
> + debug("Parsing variable's signature failed\n");
> + var_sig = NULL;
> + 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 EFIAPI efi_get_variable_common(u16 *variable_name,
> + const efi_guid_t *vendor,
> + u32 *attributes,
> + efi_uintn_t *data_size, void *data,
> + bool is_non_volatile)
> {
> char *native_name;
> efi_status_t ret;
> unsigned long in_size;
> - const char *val, *s;
> + const char *val = NULL, *s;
> + u64 time = 0;
> u32 attr;
>
> - EFI_ENTRY("\"%ls\" %pUl %p %p %p", variable_name, vendor, attributes,
> - data_size, data);
> -
> if (!variable_name || !vendor || !data_size)
> return EFI_EXIT(EFI_INVALID_PARAMETER);
>
> ret = efi_to_native(&native_name, variable_name, vendor);
> if (ret)
> - return EFI_EXIT(ret);
> + return ret;
>
> EFI_PRINT("get '%s'\n", native_name);
>
> val = env_get(native_name);
> free(native_name);
> if (!val)
> - return EFI_EXIT(EFI_NOT_FOUND);
> + return EFI_NOT_FOUND;
>
> - val = parse_attr(val, &attr);
> + val = parse_attr(val, &attr, &time);
>
> in_size = *data_size;
>
> @@ -197,7 +451,7 @@ efi_status_t EFIAPI efi_get_variable(u16 *variable_name,
>
> /* number of hexadecimal digits must be even */
> if (len & 1)
> - return EFI_EXIT(EFI_DEVICE_ERROR);
> + return EFI_DEVICE_ERROR;
>
> /* two characters per byte: */
> len /= 2;
> @@ -208,11 +462,13 @@ efi_status_t EFIAPI efi_get_variable(u16 *variable_name,
> goto out;
> }
>
> - if (!data)
> - return EFI_EXIT(EFI_INVALID_PARAMETER);
> + if (!data) {
> + debug("Variable with no data shouldn't exist.\n");
> + return EFI_INVALID_PARAMETER;
> + }
>
> if (hex2bin(data, s, len))
> - return EFI_EXIT(EFI_DEVICE_ERROR);
> + return EFI_DEVICE_ERROR;
>
> EFI_PRINT("got value: \"%s\"\n", s);
> } else if ((s = prefix(val, "(utf8)"))) {
> @@ -225,8 +481,10 @@ efi_status_t EFIAPI efi_get_variable(u16 *variable_name,
> goto out;
> }
>
> - if (!data)
> - return EFI_EXIT(EFI_INVALID_PARAMETER);
> + if (!data) {
> + debug("Variable with no data shouldn't exist.\n");
> + return EFI_INVALID_PARAMETER;
> + }
>
> memcpy(data, s, len);
> ((char *)data)[len] = '\0';
> @@ -234,13 +492,67 @@ efi_status_t EFIAPI efi_get_variable(u16 *variable_name,
> EFI_PRINT("got value: \"%s\"\n", (char *)data);
> } else {
> EFI_PRINT("invalid value: '%s'\n", val);
> - return EFI_EXIT(EFI_DEVICE_ERROR);
> + return EFI_DEVICE_ERROR;
> }
>
> out:
> if (attributes)
> *attributes = attr & EFI_VARIABLE_MASK;
>
> + return ret;
> +}
> +
> +static
> +efi_status_t EFIAPI efi_get_volatile_variable(u16 *variable_name,
> + const efi_guid_t *vendor,
> + u32 *attributes,
> + efi_uintn_t *data_size,
> + void *data)
> +{
> + return efi_get_variable_common(variable_name, vendor, attributes,
> + data_size, data, false);
> +}
> +
> +efi_status_t EFIAPI efi_get_nonvolatile_variable(u16 *variable_name,
> + const efi_guid_t *vendor,
> + u32 *attributes,
> + efi_uintn_t *data_size,
> + void *data)
> +{
> + return efi_get_variable_common(variable_name, vendor, attributes,
> + data_size, data, true);
> +}
> +
> +/**
> + * 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_volatile_variable(variable_name, vendor, attributes,
> + data_size, data);
> + if (ret == EFI_NOT_FOUND)
> + ret = efi_get_nonvolatile_variable(variable_name, vendor,
> + attributes, data_size, data);
> +
> return EFI_EXIT(ret);
> }
>
> @@ -273,6 +585,7 @@ static efi_status_t parse_uboot_variable(char *variable,
> {
> char *guid, *name, *end, c;
> unsigned long name_len;
> + u64 time;
> u16 *p;
>
> guid = strchr(variable, '_');
> @@ -307,7 +620,7 @@ static efi_status_t parse_uboot_variable(char *variable,
> *(name - 1) = c;
>
> /* attributes */
> - parse_attr(end, attributes);
> + parse_attr(end, attributes, &time);
>
> return EFI_SUCCESS;
> }
> @@ -389,7 +702,7 @@ efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size,
> list_len = hexport_r(&env_htab, '\n',
> H_MATCH_REGEX | H_MATCH_KEY,
> &efi_variables_list, 0, 1, regexlist);
> - /* 1 indicates that no match was found */
> +
> if (list_len <= 1)
> return EFI_EXIT(EFI_NOT_FOUND);
>
> @@ -402,143 +715,286 @@ efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size,
> 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)
> +static
> +efi_status_t EFIAPI 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,
> + bool is_non_volatile)
> {
> - char *native_name = NULL, *val = NULL, *s;
> - const char *old_val;
> - size_t old_size;
> - efi_status_t ret = EFI_SUCCESS;
> + 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;
>
> - EFI_ENTRY("\"%ls\" %pUl %x %zu %p", variable_name, vendor, attributes,
> - data_size, data);
> + 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 out;
> + goto err;
> }
>
> ret = efi_to_native(&native_name, variable_name, vendor);
> if (ret)
> - goto out;
> + goto err;
> +
> + /* check if a variable exists */
> + old_size = 0;
> + attr = 0;
> + ret = EFI_CALL(efi_get_variable(variable_name, vendor, &attr,
> + &old_size, NULL));
> + if (ret == EFI_BUFFER_TOO_SMALL) {
> + if ((is_non_volatile && !(attr & EFI_VARIABLE_NON_VOLATILE)) ||
> + (!is_non_volatile && (attr & EFI_VARIABLE_NON_VOLATILE))) {
> + ret = EFI_INVALID_PARAMETER;
> + goto err;
> + }
> + }
>
> - old_val = env_get(native_name);
> - if (old_val) {
> - old_val = parse_attr(old_val, &attr);
> + append = !!(attributes & EFI_VARIABLE_APPEND_WRITE);
> + attributes &= ~(u32)EFI_VARIABLE_APPEND_WRITE;
> + delete = !append && (!data_size || !attributes);
>
> - /* check read-only first */
> - if (attr & READ_ONLY) {
> + /* check attributes */
> + if (old_size) {
> + if (ro_check && (attr & READ_ONLY)) {
> ret = EFI_WRITE_PROTECTED;
> - goto out;
> - }
> -
> - if ((data_size == 0 &&
> - !(attributes & EFI_VARIABLE_APPEND_WRITE)) ||
> - !attributes) {
> - /* delete the variable: */
> - env_set(native_name, NULL);
> - ret = EFI_SUCCESS;
> - goto out;
> + goto err;
> }
>
> /* attributes won't be changed */
> - if (attr != (attributes & ~EFI_VARIABLE_APPEND_WRITE)) {
> + if (!delete &&
> + ((ro_check && attr != attributes) ||
> + (!ro_check && ((attr & ~(u32)READ_ONLY)
> + != (attributes & ~(u32)READ_ONLY))))) {
> ret = EFI_INVALID_PARAMETER;
> - goto out;
> - }
> -
> - if (attributes & EFI_VARIABLE_APPEND_WRITE) {
> - if (!prefix(old_val, "(blob)")) {
> - ret = EFI_DEVICE_ERROR;
> - goto out;
> - }
> - old_size = strlen(old_val);
> - } else {
> - old_size = 0;
> + goto err;
> }
> } else {
> - if (data_size == 0 || !attributes ||
> - (attributes & EFI_VARIABLE_APPEND_WRITE)) {
> + if (delete || append) {
> /*
> * Trying to delete or to update a non-existent
> * variable.
> */
> ret = EFI_NOT_FOUND;
> - goto out;
> + 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) {
> + return EFI_OUT_OF_RESOURCES;
> + goto err;
> + }
> + ret = EFI_CALL(efi_get_variable(variable_name, vendor,
> + &attr, &old_size, old_data));
> + if (ret != EFI_SUCCESS)
> + goto err;
> + } else {
> old_size = 0;
> }
>
> - val = malloc(old_size + 2 * data_size
> - + strlen("{ro,run,boot,nv}(blob)") + 1);
> + 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 out;
> + goto err;
> }
>
> s = val;
>
> - /* store attributes */
> - attributes &= (EFI_VARIABLE_NON_VOLATILE |
> + /*
> + * store attributes
> + */
> + attributes &= (READ_ONLY |
> + EFI_VARIABLE_NON_VOLATILE |
> EFI_VARIABLE_BOOTSERVICE_ACCESS |
> - EFI_VARIABLE_RUNTIME_ACCESS);
> + EFI_VARIABLE_RUNTIME_ACCESS |
> + EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS);
> s += sprintf(s, "{");
> while (attributes) {
> - u32 attr = 1 << (ffs(attributes) - 1);
> + attr = 1 << (ffs(attributes) - 1);
>
> - if (attr == EFI_VARIABLE_NON_VOLATILE)
> + 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)
> + } else if (attr == EFI_VARIABLE_BOOTSERVICE_ACCESS) {
> s += sprintf(s, "boot");
> - else if (attr == EFI_VARIABLE_RUNTIME_ACCESS)
> + } 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, "}");
> -
> - if (old_size)
> - /* APPEND_WRITE */
> - s += sprintf(s, old_val);
> - else
> - s += sprintf(s, "(blob)");
> + 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
> + ret = EFI_SUCCESS;
>
> -out:
> +err:
> free(native_name);
> + free(old_data);
> free(val);
>
> - return EFI_EXIT(ret);
> + return ret;
> +}
> +
> +static
> +efi_status_t EFIAPI efi_set_volatile_variable(u16 *variable_name,
> + const efi_guid_t *vendor,
> + u32 attributes,
> + efi_uintn_t data_size,
> + const void *data,
> + bool ro_check)
> +{
> + return efi_set_variable_common(variable_name, vendor, attributes,
> + data_size, data, ro_check, false);
> +}
> +
> +efi_status_t EFIAPI efi_set_nonvolatile_variable(u16 *variable_name,
> + const efi_guid_t *vendor,
> + u32 attributes,
> + efi_uintn_t data_size,
> + const void *data,
> + bool ro_check)
> +{
> + efi_status_t ret;
> +
> + ret = efi_set_variable_common(variable_name, vendor, attributes,
> + data_size, data, ro_check, true);
> +
> + return ret;
> +}
> +
> +static efi_status_t efi_set_variable_internal(u16 *variable_name,
> + const efi_guid_t *vendor,
> + u32 attributes,
> + efi_uintn_t data_size,
> + const void *data,
> + bool ro_check)
> +{
> + efi_status_t ret;
> +
> + if (attributes & EFI_VARIABLE_NON_VOLATILE)
> + ret = efi_set_nonvolatile_variable(variable_name, vendor,
> + attributes,
> + data_size, data, ro_check);
> + else
> + ret = efi_set_volatile_variable(variable_name, vendor,
> + attributes, data_size, data,
> + ro_check);
> +
> + 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_internal(variable_name, vendor,
> + attributes, data_size, data,
> + true));
> }
>
> /**
>