12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576777879808182838485868788899091929394959697989910010110210310410510610710810911011111211311411511611711811912012112212312412512612712812913013113213313413513613713813914014114214314414514614714814915015115215315415515615715815916016116216316416516616716816917017117217317417517617717817918018118218318418518618718818919019119219319419519619719819920020120220320420520620720820921021121221321421521621721821922022122222322422522622722822923023123223323423523623723823924024124224324424524624724824925025125225325425525625725825926026126226326426526626726826927027127227327427527627727827928028128228328428528628728828929029129229329429529629729829930030130230330430530630730830931031131231331431531631731831932032132232332432532632732832933033133233333433533633733833934034134234334434534634734834935035135235335435535635735835936036136236336436536636736836937037137237337437537637737837938038138238338438538638738838939039139239339439539639739839940040140240340440540640740840941041141241341441541641741841942042142242342442542642742842943043143243343443543643743843944044144244344444544644744844945045145245345445545645745845946046146246346446546646746846947047147247347447547647747847948048148248348448548648748848949049149249349449549649749849950050150250350450550650750850951051151251351451551651751851952052152252352452552652752852953053153253353453553653753853954054154254354454554654754854955055155255355455555655755855956056156256356456556656756856957057157257357457557657757857958058158258358458558658758858959059159259359459559659759859960060160260360460560660760860961061161261361461561661761861962062162262362462562662762862963063163263363463563663763863964064164264364464564664764864965065165265365465565665765865966066166266366466566666766866967067167267367467567667767867968068168268368468568668768868969069169269369469569669769869970070170270370470570670770870971071171271371471571671771871972072172272372472572672772872973073173273373473573673773873974074174274374474574674774874975075175275375475575675775875976076176276376476576676776876977077177277377477577677777877978078178278378478578678778878979079179279379479579679779879980080180280380480580680780880981081181281381481581681781881982082182282382482582682782882983083183283383483583683783883984084184284384484584684784884985085185285385485585685785885986086186286386486586686786886987087187287387487587687787887988088188288388488588688788888989089189289389489589689789889990090190290390490590690790890991091191291391491591691791891992092192292392492592692792892993093193293393493593693793893994094194294394494594694794894995095195295395495595695795895996096196296396496596696796896997097197297397497597697797897998098198298398498598698798898999099199299399499599699799899910001001100210031004100510061007100810091010101110121013101410151016101710181019102010211022102310241025102610271028102910301031103210331034103510361037103810391040104110421043104410451046104710481049105010511052105310541055105610571058105910601061106210631064106510661067106810691070107110721073107410751076107710781079108010811082108310841085108610871088108910901091109210931094109510961097109810991100110111021103110411051106110711081109111011111112111311141115111611171118111911201121112211231124112511261127112811291130113111321133113411351136113711381139114011411142114311441145114611471148114911501151115211531154115511561157115811591160116111621163116411651166116711681169117011711172117311741175117611771178117911801181118211831184118511861187118811891190119111921193119411951196119711981199120012011202120312041205120612071208120912101211121212131214121512161217121812191220122112221223122412251226122712281229123012311232123312341235123612371238123912401241 |
- // SPDX-License-Identifier: GPL-2.0+
- /*
- * UEFI runtime variable services
- *
- * Copyright (c) 2017 Rob Clark
- */
- #include <common.h>
- #include <efi_loader.h>
- #include <env.h>
- #include <env_internal.h>
- #include <hexdump.h>
- #include <malloc.h>
- #include <rtc.h>
- #include <search.h>
- #include <uuid.h>
- #include <crypto/pkcs7_parser.h>
- #include <linux/bitops.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,
- };
- 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:
- *
- * 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
- * @secure_boot: value of SecureBoot
- * @setup_mode: value of SetupMode
- * @audit_mode: value of AuditMode
- * @deployed_mode: value of DeployedMode
- *
- * Modify secure boot status related variables as indicated.
- *
- * Return: status code
- */
- static efi_status_t efi_set_secure_state(u8 secure_boot, u8 setup_mode,
- u8 audit_mode, u8 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(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);
- 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;
- EFI_PRINT("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, 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.
- */
- EFI_PRINT("Makeshift prefix added to authentication data\n");
- ebuflen = sizeof(pkcs7_hdr) + buflen;
- if (ebuflen <= 0x7f) {
- EFI_PRINT("Data is too short\n");
- return NULL;
- }
- ebuf = malloc(ebuflen);
- if (!ebuf) {
- EFI_PRINT("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;
- memcpy(×tamp, &auth->time_stamp, sizeof(timestamp));
- if (timestamp.pad1 || timestamp.nanosecond || timestamp.timezone ||
- timestamp.daylight || timestamp.pad2)
- goto err;
- *data += sizeof(auth->time_stamp) + auth->auth_info.hdr.dwLength;
- *data_size -= (sizeof(auth->time_stamp)
- + auth->auth_info.hdr.dwLength);
- 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 *)×tamp,
- (uint8_t *)×tamp + 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) {
- EFI_PRINT("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)) {
- EFI_PRINT("Verified\n");
- } else {
- if (truststore2 &&
- efi_signature_verify_with_sigdb(regs, var_sig,
- truststore2, NULL)) {
- EFI_PRINT("Verified\n");
- } else {
- EFI_PRINT("Verifying variable's signature failed\n");
- goto err;
- }
- }
- /* finished checking */
- *time = new_time;
- 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,
- u64 *timep)
- {
- 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_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);
- if (timep)
- *timep = 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) {
- EFI_PRINT("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) {
- EFI_PRINT("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, NULL);
- 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;
- 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, &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)) {
- 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)) {
- EFI_PRINT("%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)) {
- EFI_PRINT("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, NULL);
- 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;
- }
|