[PATCH 14/16] efi_loader: use memory based variable storage

Heinrich Schuchardt
2020-03-27T05:27:58Z

Saving UEFI variable as encoded U-Boot environment variables does not allow
implement run-time support.

Use a memory buffer for storing UEFI variables.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
---
lib/efi_loader/efi_variable.c | 584 +++++++----------------------
lib/efi_loader/efi_variables_mem.c | 7 +
2 files changed, 147 insertions(+), 444 deletions(-)

diff --git a/lib/efi_loader/efi_variable.c b/lib/efi_loader/efi_variable.c
index 952a0a0db7..7c39542968 100644
--- a/lib/efi_loader/efi_variable.c
+++ b/lib/efi_loader/efi_variable.c
@@ -2,152 +2,15 @@
/*
* UEFI runtime variable services
*
- * Copyright (c) 2017 Rob Clark
+ * Copyright (c) 2019 Heinrich Schuchardt
*/

#include <common.h>
#include <efi_loader.h>
#include <efi_variable.h>
-#include <env_internal.h>
-#include <hexdump.h>
-#include <malloc.h>
-#include <search.h>
-#include <u-boot/crc.h>

#define READ_ONLY BIT(31)

-/*
- * 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
- * Return: pointer to remainder of U-Boot variable value
- */
-static const char *parse_attr(const char *str, u32 *attrp)
-{
- 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 {
- printf("invalid attribute: %s\n", str);
- break;
- }
-
- str = s;
- sep = ',';
- }
-
- str++;
-
- *attrp = attr;
-
- return str;
-}
-
/**
* efi_get_variable() - retrieve value of a UEFI variable
*
@@ -167,11 +30,18 @@ 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);

- return EFI_EXIT(efi_get_variable_int(variable_name, vendor, attributes,
- data_size, data));
+ ret = efi_get_variable_int(variable_name, vendor, attributes, data_size,
+ data);
+ /* Remove read-only bit */
+ if (attributes)
+ *attributes &= EFI_VARIABLE_MASK;
+
+ return EFI_EXIT(ret);
}

/**
@@ -187,152 +57,37 @@ efi_status_t EFIAPI efi_get_variable(u16 *variable_name,
* @data: buffer to which the variable value is copied
* Return: status code
*/
-efi_status_t efi_get_variable_int(u16 *variable_name,
- const efi_guid_t *vendor, u32 *attributes,
- efi_uintn_t *data_size, void *data)
+efi_status_t __efi_runtime
+efi_get_variable_int(u16 *variable_name, const efi_guid_t *vendor,
+ u32 *attributes, efi_uintn_t *data_size, void *data)
{
- char *native_name;
- efi_status_t ret;
- unsigned long in_size;
- const char *val, *s;
- u32 attr;
-
+ efi_uintn_t old_size;
+ struct efi_var_entry *var;
+ u16 *pdata;

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)
+ var = efi_var_mem_find(vendor, variable_name, NULL);
+ if (!var)
return EFI_NOT_FOUND;

- val = parse_attr(val, &attr);
-
- 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)
- 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)
- 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;
+ *attributes = var->attr;

- return 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;
- 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)
+ old_size = *data_size;
+ *data_size = var->length;
+ if (old_size < var->length)
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;
+ if (!data)
+ return EFI_INVALID_PARAMETER;

- /* guid */
- c = *(name - 1);
- *(name - 1) = '\0'; /* guid need be null-terminated here */
- uuid_str_to_bin(guid, (unsigned char *)vendor, UUID_STR_FORMAT_GUID);
- *(name - 1) = c;
+ for (pdata = var->name; *pdata; ++pdata)
+ ;
+ ++pdata;

- /* attributes */
- parse_attr(end, attributes);
+ efi_var_mem_memcpy(data, pdata, var->length);

return EFI_SUCCESS;
}
@@ -378,78 +133,38 @@ efi_status_t EFIAPI efi_get_next_variable_name(efi_uintn_t *variable_name_size,
*
* Return: status code
*/
-efi_status_t efi_get_next_variable_name_int(efi_uintn_t *variable_name_size,
- u16 *variable_name,
- efi_guid_t *vendor)
+efi_status_t __efi_runtime
+efi_get_next_variable_name_int(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;
+ struct efi_var_entry *var;
+ efi_uintn_t old_size;
+ u16 *pdata;

if (!variable_name_size || !variable_name || !vendor)
return 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_INVALID_PARAMETER;
-
- /* search for the last-returned variable */
- ret = efi_to_native(&native_name, variable_name, vendor);
- if (ret)
- return ret;
-
- name_len = strlen(native_name);
- for (variable = efi_variables_list; variable && *variable;) {
- if (!strncmp(variable, native_name, name_len) &&
- variable[name_len] == '=')
- break;
+ if (!variable_name[0])
+ var = NULL;

- variable = strchr(variable, '\n');
- if (variable)
- variable++;
- }
+ efi_var_mem_find(vendor, variable_name, &var);
+ if (!var)
+ return EFI_NOT_FOUND;

- free(native_name);
- if (!(variable && *variable))
- return EFI_INVALID_PARAMETER;
+ for (pdata = var->name; *pdata; ++pdata)
+ ;
+ ++pdata;

- /* next variable */
- variable = strchr(variable, '\n');
- if (variable)
- variable++;
- if (!(variable && *variable))
- return 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);
- /* 1 indicates that no match was found */
- if (list_len <= 1)
- return EFI_NOT_FOUND;
+ old_size = *variable_name_size;
+ *variable_name_size = (uintptr_t)pdata - (uintptr_t)var->name;

- variable = efi_variables_list;
- }
+ if (old_size < *variable_name_size)
+ return EFI_BUFFER_TOO_SMALL;

- ret = parse_uboot_variable(variable, variable_name_size, variable_name,
- vendor, &attributes);
+ efi_var_mem_memcpy(variable_name, var->name, *variable_name_size);
+ efi_var_mem_memcpy(vendor, &var->guid, sizeof(efi_guid_t));

- return ret;
+ return EFI_SUCCESS;
}

/**
@@ -471,17 +186,26 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
const efi_guid_t *vendor, u32 attributes,
efi_uintn_t data_size, const void *data)
{
+ efi_status_t ret;
+
EFI_ENTRY("\"%ls\" %pUl %x %zu %p", variable_name, vendor, attributes,
data_size, data);

- return EFI_EXIT(efi_set_variable_int(variable_name, vendor, attributes,
- data_size, data));
+ ret = efi_set_variable_int(variable_name, vendor, attributes,
+ data_size, data);
+
+ /* Write non-volatile EFI variables to file */
+ if (ret == EFI_SUCCESS && (attributes & EFI_VARIABLE_NON_VOLATILE) &&
+ efi_obj_list_initialized == EFI_SUCCESS)
+ efi_var_to_file();
+
+ return EFI_EXIT(ret);
}

/**
- * efi_set_variable_int() - set value of a UEFI variable internal
+ * efi_set_variable_rt_int() - set value of a UEFI variable internal
*
- * This function can be used to set a UEFI variable without using EFI_CALL().
+ * This implements SetVariable() without persistence.
*
* @variable_name: name of the variable
* @vendor: vendor GUID
@@ -490,130 +214,91 @@ efi_status_t EFIAPI efi_set_variable(u16 *variable_name,
* @data: buffer with the variable value
* Return: status code
*/
-efi_status_t efi_set_variable_int(u16 *variable_name,
- const efi_guid_t *vendor, u32 attributes,
- efi_uintn_t data_size, const void *data)
+static efi_status_t __efi_runtime
+efi_set_variable_rt_int(u16 *variable_name, const efi_guid_t *vendor,
+ u32 attributes, efi_uintn_t data_size, const void *data)
{
- char *native_name = NULL, *val = NULL, *s;
- const char *old_val;
- size_t old_size;
- efi_status_t ret = EFI_SUCCESS;
- u32 attr;
-
+ struct efi_var_entry *var;
+ efi_uintn_t ret;
+ bool append;

if (!variable_name || !*variable_name || !vendor ||
((attributes & EFI_VARIABLE_RUNTIME_ACCESS) &&
!(attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS))) {
- ret = EFI_INVALID_PARAMETER;
- goto out;
+ return EFI_INVALID_PARAMETER;
}

- ret = efi_to_native(&native_name, variable_name, vendor);
- if (ret)
- goto out;
-
- old_val = env_get(native_name);
- if (old_val) {
- old_val = parse_attr(old_val, &attr);
-
- /* check read-only first */
- if (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;
- }
-
- /* attributes won't be changed */
- if (attr != (attributes & ~EFI_VARIABLE_APPEND_WRITE)) {
- ret = EFI_INVALID_PARAMETER;
+ var = efi_var_mem_find(vendor, variable_name, NULL);
+ append = attributes & EFI_VARIABLE_APPEND_WRITE;
+ attributes &= ~EFI_VARIABLE_APPEND_WRITE;
+
+ /*
+ * TODO:
+ * * authentication
+ * * checks for EFI_VARIABLE_HARDWARE_ERROR_RECORD
+ */
+ if (var) {
+ if (attributes && var->attr != attributes)
+ return EFI_INVALID_PARAMETER;
+ if (var->attr & READ_ONLY)
+ return EFI_WRITE_PROTECTED;
+ if ((!attributes || !data_size) && !append) {
+ attributes = var->attr;
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;
- }
} else {
- if (data_size == 0 || !attributes ||
- (attributes & EFI_VARIABLE_APPEND_WRITE)) {
- /*
- * Trying to delete or to update a non-existent
- * variable.
- */
- ret = EFI_NOT_FOUND;
- goto out;
- }
-
- old_size = 0;
+ if (!attributes || !data_size || append)
+ return EFI_NOT_FOUND;
}

- val = malloc(old_size + 2 * data_size
- + strlen("{ro,run,boot,nv}(blob)") + 1);
- if (!val) {
- ret = EFI_OUT_OF_RESOURCES;
- goto out;
- }
+ if (append) {
+ u16 *old_data = var->name;
+
+ for (; *old_data; ++old_data)
+ ;
+ ++old_data;

- s = val;
-
- /* store attributes */
- attributes &= (EFI_VARIABLE_NON_VOLATILE |
- EFI_VARIABLE_BOOTSERVICE_ACCESS |
- EFI_VARIABLE_RUNTIME_ACCESS);
- s += sprintf(s, "{");
- for (u32 attr_rem = attributes; attr_rem;) {
- u32 attr = 1 << (ffs(attr_rem) - 1);
-
- 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");
-
- attr_rem &= ~attr;
- if (attr_rem)
- s += sprintf(s, ",");
+ ret = efi_var_mem_ins(variable_name, vendor, attributes,
+ var->length, old_data, data_size, data);
+ } else {
+ ret = efi_var_mem_ins(variable_name, vendor, attributes,
+ data_size, data, 0, NULL);
}
- s += sprintf(s, "}");
+ if (ret != EFI_SUCCESS)
+ return ret;

- if (old_size)
- /* APPEND_WRITE */
- s += sprintf(s, old_val);
- else
- s += sprintf(s, "(blob)");
+out:
+ efi_var_mem_del(var);

- /* store payload: */
- s = bin2hex(s, data, data_size);
- *s = '\0';
+ return EFI_SUCCESS;
+}

- EFI_PRINT("setting: %s=%s\n", native_name, val);
+/**
+ * efi_set_variable_int() - set value of a UEFI variable internal
+ *
+ * This function can be used to set a UEFI variable without using EFI_CALL().
+ *
+ * @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
+efi_set_variable_int(u16 *variable_name, const efi_guid_t *vendor,
+ u32 attributes, efi_uintn_t data_size, const void *data)
+{
+ efi_status_t ret;

- if (env_set(native_name, val))
- ret = EFI_DEVICE_ERROR;
+ ret = efi_set_variable_rt_int(variable_name, vendor, attributes,
+ data_size, data);

/* Write non-volatile EFI variables to file */
- if (attributes && EFI_VARIABLE_NON_VOLATILE &&
- ret == EFI_SUCCESS && efi_obj_list_initialized == EFI_SUCCESS)
+ if (ret == EFI_SUCCESS && (attributes & EFI_VARIABLE_NON_VOLATILE) &&
+ efi_obj_list_initialized == EFI_SUCCESS)
efi_var_to_file();

-out:
- free(native_name);
- free(val);
-
return ret;
}

@@ -629,7 +314,7 @@ out:
* 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
+ * @remaining_variable_storage_size: remaining size of storage for the
* selected variable types
* @maximum_variable_size: maximum size of a variable of the
* selected type
@@ -641,6 +326,14 @@ efi_status_t __efi_runtime EFIAPI efi_query_variable_info(
u64 *remaining_variable_storage_size,
u64 *maximum_variable_size)
{
+ /*
+ *maximum_variable_storage_size = EFI_VAR_BUF_SIZE -
+ sizeof(struct efi_var_file);
+ *remaining_variable_storage_size = efi_var_mem_free();
+ *maximum_variable_size = EFI_VAR_BUF_SIZE -
+ sizeof(struct efi_var_file) -
+ sizeof(struct efi_var_entry);
+ */
return EFI_UNSUPPORTED;
}

@@ -700,9 +393,6 @@ efi_set_variable_runtime(u16 *variable_name, const efi_guid_t *vendor,
*/
void efi_variables_boot_exit_notify(void)
{
- /* Write non-volatile EFI variables to file */
- efi_var_to_file();
-
/* Switch variable services functions to runtime version */
efi_runtime_services.get_variable = efi_get_variable_runtime;
efi_runtime_services.get_next_variable_name =
@@ -718,5 +408,11 @@ void efi_variables_boot_exit_notify(void)
*/
efi_status_t efi_init_variables(void)
{
+ efi_status_t ret;
+
+ ret = efi_var_mem_init();
+ if (ret != EFI_SUCCESS)
+ return ret;
+
return efi_var_from_file();
}
diff --git a/lib/efi_loader/efi_variables_mem.c b/lib/efi_loader/efi_variables_mem.c
index f70cc65f8b..939fbaa972 100644
--- a/lib/efi_loader/efi_variables_mem.c
+++ b/lib/efi_loader/efi_variables_mem.c
@@ -263,8 +263,15 @@ static void efi_var_mem_bs_del(void)
static void EFIAPI __efi_runtime
efi_var_mem_notify_exit_boot_services(struct efi_event *event, void *context)
{
+ EFI_ENTRY("%p, %p", event, context);
+
+ /* Write non-volatile EFI variables to file */
+ efi_var_to_file();
+
/* Delete boot service only variables */
efi_var_mem_bs_del();
+
+ EFI_EXIT(EFI_SUCCESS);
}

/**
--
2.25.1