diff options
Diffstat (limited to 'src/drivers/efi/efivars.c')
| -rw-r--r-- | src/drivers/efi/efivars.c | 654 |
1 files changed, 654 insertions, 0 deletions
diff --git a/src/drivers/efi/efivars.c b/src/drivers/efi/efivars.c new file mode 100644 index 0000000000..9a3233f11c --- /dev/null +++ b/src/drivers/efi/efivars.c @@ -0,0 +1,654 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +#include <stdint.h> +#include <stdlib.h> +#include <string.h> +#include <console/console.h> + +#include <vendorcode/intel/edk2/UDK2017/MdePkg/Include/Uefi/UefiBaseType.h> +#include <vendorcode/intel/edk2/UDK2017/MdePkg/Include/Uefi/UefiMultiPhase.h> +#include <vendorcode/intel/edk2/UDK2017/MdePkg/Include/Pi/PiFirmwareVolume.h> +#include <vendorcode/intel/edk2/UDK2017/MdeModulePkg/Include/Guid/VariableFormat.h> +#include <lib.h> + +#include "efivars.h" + +#define PREFIX "EFIVARS: " + +static const EFI_GUID EfiVariableGuid = { + 0xddcf3616, 0x3275, 0x4164, { 0x98, 0xb6, 0xfe, 0x85, 0x70, 0x7f, 0xfe, 0x7d } }; +static const EFI_GUID EfiAuthenticatedVariableGuid = { + 0xaaf32c78, 0x947b, 0x439a, { 0xa1, 0x80, 0x2e, 0x14, 0x4e, 0xc3, 0x77, 0x92 } }; +static const EFI_GUID EfiSystemNvDataFvGuid = { + 0xfff12b8d, 0x7696, 0x4c8b, { 0xa9, 0x85, 0x27, 0x47, 0x07, 0x5b, 0x4f, 0x50 } }; + +static void print_guid(int log_level, const EFI_GUID *g) +{ + printk(log_level, "GUID: %08x-%04x-%04x-%02x%02x%02x%02x%02x%02x%02x%02x", + g->Data1, g->Data2, g->Data3, g->Data4[0], g->Data4[1], g->Data4[2], + g->Data4[3], g->Data4[4], g->Data4[5], g->Data4[6], g->Data4[7]); + +} + +static bool compare_guid(const EFI_GUID *a, const EFI_GUID *b) +{ + return memcmp(a, b, sizeof(*a)) == 0; +} + +/* Reads the CHAR16 string from rdev at offset and prints it */ +static enum cb_err rdev_print_wchar(int log_level, struct region_device *rdev, size_t offset) +{ + CHAR16 c; + int i = 0; + + /* Convert ASCII to UTF-16 */ + do { + if (rdev_readat(rdev, &c, offset + i * sizeof(c), sizeof(c)) != sizeof(c)) + return CB_EFI_ACCESS_ERROR; + if (c < 0x80) + printk(log_level, "%c", (char)c); + else + printk(log_level, "\\u%04x", c); + + i++; + } while (c); + return CB_SUCCESS; +} + +/* Convert an ASCII string to UTF-16 and write it to the rdev starting at offset. */ +static enum cb_err rdev_write_wchar(struct region_device *rdev, size_t offset, const char *msg) +{ + size_t i; + CHAR16 c; + + /* Convert ASCII to UTF-16 */ + for (i = 0; i < strlen(msg) + 1; i++) { + c = msg[i]; + + if (rdev_writeat(rdev, &c, offset + i * sizeof(c), sizeof(c)) != sizeof(c)) + return CB_EFI_ACCESS_ERROR; + } + return CB_SUCCESS; +} + +/* Read an UTF-16 string from rdev at offset and compare it to ASCII string */ +static int rdev_strcmp_wchar_ascii(struct region_device *rdev, size_t offset, const char *msg) +{ + size_t i; + CHAR16 c; + int r; + + i = 0; + /* Compare UTF-16 and ASCII */ + while (1) { + if (rdev_readat(rdev, &c, offset + i * sizeof(c), sizeof(c)) != sizeof(c)) + return CB_EFI_ACCESS_ERROR; + if ((r = (c - msg[i])) != 0 || !c) + break; + + i++; + } + return r; +} + +/* Compare an rdev region and a data buffer */ +static int rdev_memcmp(struct region_device *rdev, size_t offset, uint8_t *data, size_t size) +{ + uint8_t buf[16]; + size_t i; + int r; + + i = 0; + while (size >= sizeof(buf)) { + if (rdev_readat(rdev, buf, offset + i, sizeof(buf)) != sizeof(buf)) + return CB_EFI_ACCESS_ERROR; + r = memcmp(buf, data + i, sizeof(buf)); + if (r != 0) + return r; + i += sizeof(buf); + size -= sizeof(buf); + } + while (size > 0) { + if (rdev_readat(rdev, buf, offset + i, 1) != 1) + return CB_EFI_ACCESS_ERROR; + r = buf[0] - data[i]; + if (r != 0) + return r; + i++; + size--; + } + return 0; +} + + +static enum cb_err validate_fv_header(const struct region_device *rdev, + EFI_FIRMWARE_VOLUME_HEADER *fw_vol_hdr) +{ + uint16_t checksum, data; + size_t i; + + if (rdev_readat(rdev, fw_vol_hdr, 0, sizeof(*fw_vol_hdr)) != sizeof(*fw_vol_hdr)) + return CB_EFI_ACCESS_ERROR; + + /* + * Verify the header revision, header signature, length + * Length of FvBlock cannot be 2**64-1 + * HeaderLength cannot be an odd number + */ + if ((fw_vol_hdr->Revision != EFI_FVH_REVISION) + || (fw_vol_hdr->Signature != EFI_FVH_SIGNATURE) + || (fw_vol_hdr->FvLength > region_device_sz(rdev)) + || (fw_vol_hdr->HeaderLength > region_device_sz(rdev)) + || (fw_vol_hdr->HeaderLength & 1)) { + printk(BIOS_WARNING, PREFIX "No Firmware Volume header present\n"); + return CB_EFI_FVH_INVALID; + } + + /* Check the Firmware Volume Guid */ + if (!compare_guid(&fw_vol_hdr->FileSystemGuid, &EfiSystemNvDataFvGuid)) { + printk(BIOS_WARNING, PREFIX "Firmware Volume Guid non-compatible\n"); + return CB_EFI_FVH_INVALID; + } + + /* Verify the header checksum */ + checksum = 0; + for (i = 0; i < fw_vol_hdr->HeaderLength; i += 2) { + if (rdev_readat(rdev, &data, i, sizeof(data)) != sizeof(data)) + return CB_EFI_ACCESS_ERROR; + checksum = (uint16_t)(checksum + data); /* intentionally overflows */ + } + if (checksum != 0) { + printk(BIOS_WARNING, PREFIX "FV checksum is invalid: 0x%X\n", checksum); + return CB_EFI_CHECKSUM_INVALID; + } + + printk(BIOS_SPEW, PREFIX "UEFI FV with size %lld found\n", fw_vol_hdr->FvLength); + + return CB_SUCCESS; + +} + +static enum cb_err +validate_variable_store_header(const EFI_FIRMWARE_VOLUME_HEADER *fv_hdr, + struct region_device *rdev, + bool *auth_format) +{ + VARIABLE_STORE_HEADER hdr; + size_t length; + + if (rdev_readat(rdev, &hdr, fv_hdr->HeaderLength, sizeof(hdr)) != sizeof(hdr)) + return CB_EFI_ACCESS_ERROR; + + /* Check the Variable Store Guid */ + if (!compare_guid(&hdr.Signature, &EfiVariableGuid) && + !compare_guid(&hdr.Signature, &EfiAuthenticatedVariableGuid)) { + printk(BIOS_WARNING, PREFIX "Variable Store Guid non-compatible\n"); + return CB_EFI_VS_CORRUPTED_INVALID; + } + + *auth_format = compare_guid(&hdr.Signature, &EfiAuthenticatedVariableGuid); + + length = region_device_sz(rdev) - fv_hdr->HeaderLength; + if (hdr.Size > length) { + printk(BIOS_WARNING, PREFIX "Variable Store Length does not match\n"); + return CB_EFI_VS_CORRUPTED_INVALID; + } + + if (hdr.Format != VARIABLE_STORE_FORMATTED) + return CB_EFI_VS_NOT_FORMATTED_INVALID; + + if (hdr.State != VARIABLE_STORE_HEALTHY) + return CB_EFI_VS_CORRUPTED_INVALID; + + if (rdev_chain(rdev, rdev, fv_hdr->HeaderLength + sizeof(hdr), hdr.Size)) { + printk(BIOS_WARNING, PREFIX "rdev_chain failed\n"); + return CB_EFI_ACCESS_ERROR; + } + + printk(BIOS_SPEW, PREFIX "UEFI variable store with size %zu found\n", + region_device_sz(rdev)); + + return CB_SUCCESS; +} + +struct efi_find_args { + const EFI_GUID *guid; + const char *name; + uint32_t *size; + void *data; +}; + +static bool match(struct region_device *rdev, VARIABLE_HEADER *hdr, size_t hdr_size, + const char *name, const EFI_GUID *guid) +{ + /* Only search for valid or in transition to be deleted variables */ + if ((hdr->State != VAR_ADDED) && + (hdr->State != (VAR_IN_DELETED_TRANSITION & VAR_ADDED))) + return false; + + if ((!compare_guid(&hdr->VendorGuid, guid)) || + !hdr->NameSize || + !hdr->DataSize) + return false; + + if (rdev_strcmp_wchar_ascii(rdev, hdr_size, name) != 0) + return false; + + return true; +} + +static +enum cb_err find_and_copy(struct region_device *rdev, VARIABLE_HEADER *hdr, size_t hdr_size, + void *arg, bool *stop) +{ + struct efi_find_args *fa = (struct efi_find_args *)arg; + + if (!match(rdev, hdr, hdr_size, fa->name, fa->guid)) + return CB_SUCCESS; + + *stop = true; + if (*(fa->size) < hdr->DataSize) + return CB_EFI_BUFFER_TOO_SMALL; + + if (rdev_readat(rdev, fa->data, hdr_size + hdr->NameSize, hdr->DataSize) != + hdr->DataSize) + return CB_EFI_ACCESS_ERROR; + + *(fa->size) = hdr->DataSize; + return CB_SUCCESS; +} + +struct efi_find_compare_args { + const EFI_GUID *guid; + const char *name; + uint32_t size; + void *data; + bool match; +}; + +static +enum cb_err find_and_compare(struct region_device *rdev, VARIABLE_HEADER *hdr, size_t hdr_size, + void *arg, bool *stop) +{ + struct efi_find_compare_args *fa = (struct efi_find_compare_args *)arg; + + if (!match(rdev, hdr, hdr_size, fa->name, fa->guid)) + return CB_SUCCESS; + + *stop = true; + if (fa->size != hdr->DataSize) { + fa->match = false; + return CB_SUCCESS; + } + + fa->match = rdev_memcmp(rdev, hdr_size + hdr->NameSize, fa->data, hdr->DataSize) == 0; + + return CB_SUCCESS; +} + +static enum cb_err noop(struct region_device *rdev, VARIABLE_HEADER *hdr, size_t hdr_size, + void *arg, bool *stop) +{ + /* Does nothing. */ + return CB_SUCCESS; +} + +static enum cb_err print_var(struct region_device *rdev, VARIABLE_HEADER *hdr, size_t hdr_size, + void *arg, bool *stop) +{ + uint8_t buf[16]; + size_t len, i; + + printk(BIOS_DEBUG, "%08zx: Var ", region_device_offset(rdev)); + print_guid(BIOS_DEBUG, &hdr->VendorGuid); + + printk(BIOS_DEBUG, "-"); + + rdev_print_wchar(BIOS_DEBUG, rdev, hdr_size); + + printk(BIOS_DEBUG, ", State %02x, Size %02x\n", hdr->State, hdr->DataSize); + + if (hdr->DataSize && hdr->NameSize) { + len = sizeof(buf) < hdr->DataSize ? sizeof(buf) : hdr->DataSize; + if (rdev_readat(rdev, buf, hdr_size + hdr->NameSize, len) != len) + return CB_EFI_ACCESS_ERROR; + printk(BIOS_DEBUG, " Data: "); + + for (i = 0; i < len; i++) + printk(BIOS_DEBUG, "0x%02x ", buf[i]); + + if (hdr->DataSize > len) + printk(BIOS_DEBUG, "..."); + + printk(BIOS_DEBUG, "\n"); + } + + return CB_SUCCESS; +} + +static enum cb_err walk_variables(struct region_device *rdev, + bool auth_format, + enum cb_err (*walker)(struct region_device *rdev, + VARIABLE_HEADER *hdr, + size_t hdr_size, + void *arg, + bool *stop), + void *walker_arg) +{ + AUTHENTICATED_VARIABLE_HEADER auth_hdr; + size_t header_size, var_size; + VARIABLE_HEADER hdr; + bool stop; + enum cb_err ret; + + if (auth_format) + header_size = sizeof(AUTHENTICATED_VARIABLE_HEADER); + else + header_size = sizeof(VARIABLE_HEADER); + + do { + if (auth_format) { + if (rdev_readat(rdev, &auth_hdr, 0, sizeof(auth_hdr)) + != sizeof(auth_hdr)) + return CB_EFI_ACCESS_ERROR; + hdr.Reserved = auth_hdr.Reserved; + hdr.StartId = auth_hdr.StartId; + hdr.State = auth_hdr.State; + hdr.Attributes = auth_hdr.Attributes; + hdr.NameSize = auth_hdr.NameSize; + hdr.DataSize = auth_hdr.DataSize; + memcpy(&hdr.VendorGuid, &auth_hdr.VendorGuid, sizeof(hdr.VendorGuid)); + } else if (rdev_readat(rdev, &hdr, 0, sizeof(hdr)) != sizeof(hdr)) { + return CB_EFI_ACCESS_ERROR; + } + if (hdr.StartId != VARIABLE_DATA) + break; + + if (hdr.State == UINT8_MAX || + hdr.DataSize == UINT32_MAX || + hdr.NameSize == UINT32_MAX || + hdr.Attributes == UINT32_MAX) { + hdr.NameSize = 0; + hdr.DataSize = 0; + } + + printk(BIOS_SPEW, "Found variable with state %02x and ", hdr.State); + print_guid(BIOS_SPEW, &hdr.VendorGuid); + printk(BIOS_SPEW, "\n"); + + stop = false; + + ret = walker(rdev, &hdr, header_size, walker_arg, &stop); + + if (ret != CB_SUCCESS || stop) + return ret; + + var_size = ALIGN_UP(header_size + hdr.NameSize + hdr.DataSize, + HEADER_ALIGNMENT); + } while (!rdev_chain(rdev, rdev, var_size, region_device_sz(rdev) - var_size)); + + return CB_EFI_OPTION_NOT_FOUND; +} + +static enum cb_err efi_fv_init(struct region_device *rdev, bool *auth_format) +{ + EFI_FIRMWARE_VOLUME_HEADER fv_hdr; + enum cb_err ret; + + ret = validate_fv_header(rdev, &fv_hdr); + if (ret != CB_SUCCESS) { + printk(BIOS_WARNING, PREFIX "Failed to validate firmware header\n"); + + return ret; + } + ret = validate_variable_store_header(&fv_hdr, rdev, auth_format); + if (ret != CB_SUCCESS) + printk(BIOS_WARNING, PREFIX "Failed to validate variable store header\n"); + + return ret; +} + +enum cb_err efi_fv_print_options(struct region_device *rdev) +{ + enum cb_err ret; + bool auth_format; + + ret = efi_fv_init(rdev, &auth_format); + if (ret != CB_SUCCESS) + return ret; + + return walk_variables(rdev, auth_format, print_var, NULL); +} + +/* + * efi_fv_get_option + * - writes up to *size bytes into a buffer pointed to by *dest + * - rdev is the spi flash region to operate on + * - the FVH and variable store header must have been initialized by a third party + */ +enum cb_err efi_fv_get_option(struct region_device *rdev, + const EFI_GUID *guid, + const char *name, + void *dest, + uint32_t *size) +{ + struct efi_find_args args; + bool auth_format; + enum cb_err ret; + + ret = efi_fv_init(rdev, &auth_format); + if (ret != CB_SUCCESS) + return ret; + + args.guid = guid; + args.name = name; + args.size = size; + args.data = dest; + + return walk_variables(rdev, auth_format, find_and_copy, &args); +} + +static enum cb_err write_auth_hdr(struct region_device *rdev, const EFI_GUID *guid, + const char *name, void *data, size_t size) +{ + AUTHENTICATED_VARIABLE_HEADER auth_hdr; + size_t name_size, var_size; + enum cb_err ret; + + name_size = (strlen(name) + 1) * sizeof(CHAR16); + var_size = name_size + size + sizeof(auth_hdr); + + if (var_size > region_device_sz(rdev)) + return CB_EFI_STORE_FULL; + + /* Sanity check. flash must be blank */ + if (rdev_readat(rdev, &auth_hdr, 0, sizeof(auth_hdr)) != sizeof(auth_hdr)) + return CB_EFI_ACCESS_ERROR; + + if (auth_hdr.StartId != UINT16_MAX || + auth_hdr.State != UINT8_MAX || + auth_hdr.DataSize != UINT32_MAX || + auth_hdr.NameSize != UINT32_MAX || + auth_hdr.Attributes != UINT32_MAX) { + return CB_EFI_ACCESS_ERROR; + } + + memset(&auth_hdr, 0xff, sizeof(auth_hdr)); + + auth_hdr.StartId = VARIABLE_DATA; + auth_hdr.Attributes = EFI_VARIABLE_NON_VOLATILE| + EFI_VARIABLE_BOOTSERVICE_ACCESS| + EFI_VARIABLE_RUNTIME_ACCESS; + auth_hdr.NameSize = name_size; + auth_hdr.DataSize = size; + memcpy(&auth_hdr.VendorGuid, guid, sizeof(EFI_GUID)); + + /* Write header with no State */ + if (rdev_writeat(rdev, &auth_hdr, 0, sizeof(auth_hdr)) != sizeof(auth_hdr)) + return CB_EFI_ACCESS_ERROR; + + /* Set header State to valid header */ + auth_hdr.State = VAR_HEADER_VALID_ONLY; + if (rdev_writeat(rdev, &auth_hdr.State, offsetof(AUTHENTICATED_VARIABLE_HEADER, State), + sizeof(auth_hdr.State)) != sizeof(auth_hdr.State)) + return CB_EFI_ACCESS_ERROR; + + /* Write the name */ + ret = rdev_write_wchar(rdev, sizeof(auth_hdr), name); + if (ret != CB_SUCCESS) + return ret; + + /* Write the data */ + if (rdev_writeat(rdev, data, sizeof(auth_hdr) + name_size, size) != size) + return CB_EFI_ACCESS_ERROR; + + /* Set header State to valid data */ + auth_hdr.State = VAR_ADDED; + if (rdev_writeat(rdev, &auth_hdr.State, offsetof(AUTHENTICATED_VARIABLE_HEADER, State), + sizeof(auth_hdr.State)) != sizeof(auth_hdr.State)) + return CB_EFI_ACCESS_ERROR; + + return CB_SUCCESS; +} + +static enum cb_err write_hdr(struct region_device *rdev, const EFI_GUID *guid, + const char *name, + void *data, + size_t size) +{ + VARIABLE_HEADER hdr; + size_t name_size, var_size; + enum cb_err ret; + + name_size = (strlen(name) + 1) * sizeof(CHAR16); + var_size = name_size + size + sizeof(hdr); + if (var_size > region_device_sz(rdev)) + return CB_EFI_STORE_FULL; + + /* Sanity check. flash must be blank */ + if (rdev_readat(rdev, &hdr, 0, sizeof(hdr)) != sizeof(hdr)) + return CB_EFI_ACCESS_ERROR; + + if (hdr.StartId != UINT16_MAX || + hdr.State != UINT8_MAX || + hdr.DataSize != UINT32_MAX || + hdr.NameSize != UINT32_MAX || + hdr.Attributes != UINT32_MAX) { + return CB_EFI_ACCESS_ERROR; + } + + memset(&hdr, 0xff, sizeof(hdr)); + + hdr.StartId = VARIABLE_DATA; + hdr.Attributes = EFI_VARIABLE_NON_VOLATILE| + EFI_VARIABLE_BOOTSERVICE_ACCESS| + EFI_VARIABLE_RUNTIME_ACCESS; + hdr.NameSize = name_size; + hdr.DataSize = size; + memcpy(&hdr.VendorGuid, guid, sizeof(EFI_GUID)); + + /* Write header with no State */ + if (rdev_writeat(rdev, &hdr, 0, sizeof(hdr)) != sizeof(hdr)) + return CB_EFI_ACCESS_ERROR; + + /* Set header State to valid header */ + hdr.State = VAR_HEADER_VALID_ONLY; + if (rdev_writeat(rdev, &hdr.State, offsetof(VARIABLE_HEADER, State), + sizeof(hdr.State)) != sizeof(hdr.State)) + return CB_EFI_ACCESS_ERROR; + + /* Write the name */ + ret = rdev_write_wchar(rdev, sizeof(hdr), name); + if (ret != CB_SUCCESS) + return ret; + + /* Write the data */ + if (rdev_writeat(rdev, data, sizeof(hdr) + name_size, size) != size) + return CB_EFI_ACCESS_ERROR; + + /* Set header State to valid data */ + hdr.State = VAR_ADDED; + if (rdev_writeat(rdev, &hdr.State, offsetof(VARIABLE_HEADER, State), + sizeof(hdr.State)) != sizeof(hdr.State)) + return CB_EFI_ACCESS_ERROR; + + return CB_SUCCESS; +} + +/* + * efi_fv_set_option + * - writes size bytes read from the buffer pointed to by *data + * - rdev is the spi flash region to operate on + * - the FVH and variable store header must have been initialized by a third party + */ +enum cb_err efi_fv_set_option(struct region_device *rdev, + const EFI_GUID *guid, + const char *name, + void *data, + uint32_t size) +{ + struct region_device rdev_old; + struct efi_find_compare_args args; + bool found_existing; + VARIABLE_HEADER hdr; + bool auth_format; + enum cb_err ret; + + ret = efi_fv_init(rdev, &auth_format); + if (ret != CB_SUCCESS) + return ret; + + /* Find existing variable */ + args.guid = guid; + args.name = name; + args.size = size; + args.match = false; + args.data = data; + + ret = walk_variables(rdev, auth_format, find_and_compare, &args); + found_existing = ret == CB_SUCCESS; + + if (found_existing) { + printk(BIOS_ERR, "found existing variable %s, match =%d\n", name, args.match); + + if (args.match) + return CB_SUCCESS; + + rdev_old = *rdev; + + /* Mark as to be deleted */ + hdr.State = VAR_IN_DELETED_TRANSITION; + if (rdev_writeat(rdev, &hdr.State, offsetof(VARIABLE_HEADER, State), + sizeof(hdr.State)) != sizeof(hdr.State)) + return CB_EFI_ACCESS_ERROR; + } + + /* Walk to end of variable store */ + ret = walk_variables(rdev, auth_format, noop, NULL); + if (ret != CB_EFI_OPTION_NOT_FOUND) + return ret; + + /* Now append new variable: + * 1. Write the header without State field. + * 2. Write the State field and set it to HEADER_VALID. + * 3. Write data + * 4. Write the State field and set it to VAR_ADDED + */ + + if (auth_format) + ret = write_auth_hdr(rdev, guid, name, data, size); + else + ret = write_hdr(rdev, guid, name, data, size); + if (ret != CB_SUCCESS) + return ret; + + if (found_existing) { + /* Mark old variable as deleted */ + hdr.State = VAR_DELETED; + if (rdev_writeat(&rdev_old, &hdr.State, offsetof(VARIABLE_HEADER, State), + sizeof(hdr.State)) != sizeof(hdr.State)) + return CB_EFI_ACCESS_ERROR; + } + + return CB_SUCCESS; +} |