This is the uefi variable service (EfiSmmVariableProtocol),
providing functions for reading and writing variables.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
hw/uefi/var-service-vars.c | 602 +++++++++++++++++++++++++++++++++++++
1 file changed, 602 insertions(+)
create mode 100644 hw/uefi/var-service-vars.c
diff --git a/hw/uefi/var-service-vars.c b/hw/uefi/var-service-vars.c
new file mode 100644
index 000000000000..99851a057bb6
--- /dev/null
+++ b/hw/uefi/var-service-vars.c
@@ -0,0 +1,602 @@
+/*
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ *
+ * uefi vars device - EfiSmmVariableProtocol implementation
+ */
+#include "qemu/osdep.h"
+#include "sysemu/dma.h"
+#include "migration/vmstate.h"
+
+#include "hw/uefi/var-service.h"
+#include "hw/uefi/var-service-api.h"
+#include "hw/uefi/var-service-edk2.h"
+
+#include "trace/trace-hw_uefi.h"
+
+const VMStateDescription vmstate_uefi_variable = {
+ .name = "uefi-variable",
+ .fields = (VMStateField[]) {
+ VMSTATE_UINT8_ARRAY_V(guid.data, uefi_variable, sizeof(QemuUUID), 0),
+ VMSTATE_UINT32(name_size, uefi_variable),
+ VMSTATE_UINT32(data_size, uefi_variable),
+ VMSTATE_UINT32(attributes, uefi_variable),
+ VMSTATE_VBUFFER_ALLOC_UINT32(name, uefi_variable, 0, NULL, name_size),
+ VMSTATE_VBUFFER_ALLOC_UINT32(data, uefi_variable, 0, NULL, data_size),
+ VMSTATE_END_OF_LIST()
+ },
+};
+
+uefi_variable *uefi_vars_find_variable(uefi_vars_state *uv, QemuUUID guid,
+ const uint16_t *name, uint64_t name_size)
+{
+ uefi_variable *var;
+
+ QTAILQ_FOREACH(var, &uv->variables, next) {
+ if (!uefi_str_equal(var->name, var->name_size,
+ name, name_size)) {
+ continue;
+ }
+ if (!qemu_uuid_is_equal(&var->guid, &guid)) {
+ continue;
+ }
+ return var;
+ }
+ return NULL;
+}
+
+static uefi_variable *add_variable(uefi_vars_state *uv, QemuUUID guid,
+ const uint16_t *name, uint64_t name_size,
+ uint32_t attributes)
+{
+ uefi_variable *var;
+
+ var = g_new0(uefi_variable, 1);
+ var->guid = guid;
+ var->name = g_malloc(name_size);
+ memcpy(var->name, name, name_size);
+ var->name_size = name_size;
+ var->attributes = attributes;
+
+ QTAILQ_INSERT_TAIL(&uv->variables, var, next);
+ return var;
+}
+
+static void del_variable(uefi_vars_state *uv, uefi_variable *var)
+{
+ if (!var) {
+ return;
+ }
+
+ QTAILQ_REMOVE(&uv->variables, var, next);
+ g_free(var->data);
+ g_free(var->name);
+ g_free(var);
+}
+
+static size_t variable_size(uefi_variable *var)
+{
+ size_t size;
+
+ size = sizeof(*var);
+ size += var->name_size;
+ size += var->data_size;
+ return size;
+}
+
+void uefi_vars_set_variable(uefi_vars_state *uv, QemuUUID guid,
+ const uint16_t *name, uint64_t name_size,
+ uint32_t attributes,
+ void *data, uint64_t data_size)
+{
+ uefi_variable *old_var, *new_var;
+
+ uefi_trace_variable(__func__, guid, name, name_size);
+
+ old_var = uefi_vars_find_variable(uv, guid, name, name_size);
+ if (old_var) {
+ uv->used_storage -= variable_size(old_var);
+ del_variable(uv, old_var);
+ }
+
+ new_var = add_variable(uv, guid, name, name_size, attributes);
+ new_var->data = g_malloc(data_size);
+ new_var->data_size = data_size;
+ memcpy(new_var->data, data, data_size);
+ uv->used_storage += variable_size(new_var);
+}
+
+void uefi_vars_clear_volatile(uefi_vars_state *uv)
+{
+ uefi_variable *var, *n;
+
+ QTAILQ_FOREACH_SAFE(var, &uv->variables, next, n) {
+ if (var->attributes & EFI_VARIABLE_NON_VOLATILE) {
+ continue;
+ }
+ uv->used_storage -= variable_size(var);
+ del_variable(uv, var);
+ }
+}
+
+void uefi_vars_clear_all(uefi_vars_state *uv)
+{
+ uefi_variable *var, *n;
+
+ QTAILQ_FOREACH_SAFE(var, &uv->variables, next, n) {
+ del_variable(uv, var);
+ }
+ uv->used_storage = 0;
+}
+
+void uefi_vars_update_storage(uefi_vars_state *uv)
+{
+ uefi_variable *var;
+
+ uv->used_storage = 0;
+ QTAILQ_FOREACH(var, &uv->variables, next) {
+ uv->used_storage += variable_size(var);
+ }
+}
+
+static efi_status check_secure_boot(uefi_vars_state *uv, uefi_variable *var)
+{
+ static const uint16_t pk[] = { 'P', 'K', 0 };
+ static const uint16_t kek[] = { 'K', 'E', 'K', 0 };
+ static const uint16_t db[] = { 'd', 'b', 0 };
+ static const uint16_t dbx[] = { 'd', 'b', 'x', 0 };
+
+ /* TODO (reject for now) */
+ if (qemu_uuid_is_equal(&var->guid, &EfiGlobalVariable) &&
+ uefi_str_equal(var->name, var->name_size, pk, sizeof(pk))) {
+ return EFI_WRITE_PROTECTED;
+ }
+ if (qemu_uuid_is_equal(&var->guid, &EfiGlobalVariable) &&
+ uefi_str_equal(var->name, var->name_size, kek, sizeof(kek))) {
+ return EFI_WRITE_PROTECTED;
+ }
+
+ if (qemu_uuid_is_equal(&var->guid, &EfiImageSecurityDatabase) &&
+ uefi_str_equal(var->name, var->name_size, db, sizeof(db))) {
+ return EFI_WRITE_PROTECTED;
+ }
+ if (qemu_uuid_is_equal(&var->guid, &EfiImageSecurityDatabase) &&
+ uefi_str_equal(var->name, var->name_size, dbx, sizeof(dbx))) {
+ return EFI_WRITE_PROTECTED;
+ }
+
+ return EFI_SUCCESS;
+}
+
+static gboolean check_access(uefi_vars_state *uv, uefi_variable *var)
+{
+ if (!uv->exit_boot_service) {
+ if (!(var->attributes & EFI_VARIABLE_BOOTSERVICE_ACCESS)) {
+ return false;
+ }
+ } else {
+ if (!(var->attributes & EFI_VARIABLE_RUNTIME_ACCESS)) {
+ return false;
+ }
+ }
+ return true;
+}
+
+static efi_status check_update(uefi_vars_state *uv, uefi_variable *old_var,
+ uefi_variable *new_var)
+{
+ efi_status status;
+
+ if (old_var) {
+ if (!check_access(uv, old_var)) {
+ return EFI_ACCESS_DENIED;
+ }
+ if (old_var->attributes &
+ (EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS |
+ EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS)) {
+ /* TODO (reject for now) */
+ return EFI_WRITE_PROTECTED;
+ }
+ }
+
+ if (new_var) {
+ if (!check_access(uv, new_var)) {
+ return EFI_ACCESS_DENIED;
+ }
+ }
+
+ if (old_var && new_var) {
+ if (old_var->attributes != new_var->attributes) {
+ return EFI_INVALID_PARAMETER;
+ }
+ }
+
+ if (new_var) {
+ /* create + update */
+ status = uefi_vars_policy_check(uv, new_var, old_var == NULL);
+ } else if (old_var) {
+ /* delete */
+ status = uefi_vars_policy_check(uv, old_var, false);
+ }
+ if (status != EFI_SUCCESS) {
+ return status;
+ }
+
+ status = check_secure_boot(uv, new_var ?: old_var);
+ if (status != EFI_SUCCESS) {
+ return status;
+ }
+
+ return EFI_SUCCESS;
+}
+
+static size_t uefi_vars_mm_error(mm_header *mhdr, mm_variable *mvar,
+ uint64_t status)
+{
+ mvar->status = status;
+ return sizeof(*mvar);
+}
+
+static size_t uefi_vars_mm_get_variable(uefi_vars_state *uv, mm_header *mhdr,
+ mm_variable *mvar, void *func)
+{
+ mm_variable_access *va = func;
+ uint16_t *name;
+ void *data;
+ uefi_variable *var;
+ size_t length;
+
+ length = sizeof(*mvar) + sizeof(*va);
+ if (mhdr->length < length) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE);
+ }
+
+ if (va->name_size > uv->max_storage ||
+ va->data_size > uv->max_storage) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_OUT_OF_RESOURCES);
+ }
+
+ name = func + sizeof(*va);
+ length += va->name_size;
+ if (mhdr->length < length) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE);
+ }
+
+ uefi_trace_variable(__func__, va->guid, name, va->name_size);
+
+ var = uefi_vars_find_variable(uv, va->guid, name, va->name_size);
+ if (!var) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_NOT_FOUND);
+ }
+
+ /* check permissions etc. */
+ if (!check_access(uv, var)) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_ACCESS_DENIED);
+ }
+
+ data = func + sizeof(*va) + va->name_size;
+ length += var->data_size;
+ if (uv->buf_size < length) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE);
+ }
+
+ va->attributes = var->attributes;
+ va->data_size = var->data_size;
+ memcpy(data, var->data, var->data_size);
+ mvar->status = EFI_SUCCESS;
+ return length;
+}
+
+static size_t
+uefi_vars_mm_get_next_variable(uefi_vars_state *uv, mm_header *mhdr,
+ mm_variable *mvar, void *func)
+{
+ mm_next_variable *nv = func;
+ uefi_variable *var;
+ uint16_t *name;
+ size_t length;
+
+ length = sizeof(*mvar) + sizeof(*nv);
+ if (mhdr->length < length) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE);
+ }
+
+ if (nv->name_size > uv->max_storage) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_OUT_OF_RESOURCES);
+ }
+
+ name = func + sizeof(*nv);
+ length += nv->name_size;
+ if (mhdr->length < length) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE);
+ }
+
+ if (uefi_strlen(name, nv->name_size) == 0) {
+ /* empty string -> first */
+ var = QTAILQ_FIRST(&uv->variables);
+ if (!var) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_NOT_FOUND);
+ }
+ } else {
+ var = uefi_vars_find_variable(uv, nv->guid, name, nv->name_size);
+ if (!var) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_INVALID_PARAMETER);
+ }
+ do {
+ var = QTAILQ_NEXT(var, next);
+ } while (var && !check_access(uv, var));
+ if (!var) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_NOT_FOUND);
+ }
+ }
+
+ length = sizeof(*mvar) + sizeof(*nv) + var->name_size;
+ if (uv->buf_size < length) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE);
+ }
+
+ nv->guid = var->guid;
+ nv->name_size = var->name_size;
+ memcpy(name, var->name, var->name_size);
+ mvar->status = EFI_SUCCESS;
+ return length;
+}
+
+static size_t uefi_vars_mm_set_variable(uefi_vars_state *uv, mm_header *mhdr,
+ mm_variable *mvar, void *func)
+{
+ mm_variable_access *va = func;
+ uint32_t attributes = 0;
+ uint16_t *name;
+ void *data;
+ uefi_variable *old_var, *new_var;
+ size_t length, new_storage;
+ efi_status status;
+
+ length = sizeof(*mvar) + sizeof(*va);
+ if (mhdr->length < length) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE);
+ }
+
+ if (va->name_size > uv->max_storage ||
+ va->data_size > uv->max_storage) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_OUT_OF_RESOURCES);
+ }
+
+ name = func + sizeof(*va);
+ length += va->name_size;
+ if (mhdr->length < length) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE);
+ }
+
+ data = func + sizeof(*va) + va->name_size;
+ length += va->data_size;
+ if (mhdr->length < length) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE);
+ }
+
+ g_assert(va->name_size < G_MAXUINT32);
+ g_assert(va->data_size < G_MAXUINT32);
+
+ uefi_trace_variable(__func__, va->guid, name, va->name_size);
+
+ old_var = uefi_vars_find_variable(uv, va->guid, name, va->name_size);
+ if (va->data_size) {
+ new_var = add_variable(uv, va->guid, name, va->name_size,
+ va->attributes);
+ new_var->data = g_malloc(va->data_size);
+ memcpy(new_var->data, data, va->data_size);
+ new_var->data_size = va->data_size;
+ } else {
+ new_var = NULL;
+ }
+
+ if (!old_var && !new_var) {
+ /* delete non-existing variable -> nothing to do */
+ mvar->status = EFI_SUCCESS;
+ return sizeof(*mvar);
+ }
+
+ /* check permissions etc. */
+ status = check_update(uv, old_var, new_var);
+ if (status != EFI_SUCCESS) {
+ mvar->status = status;
+ goto rollback;
+ }
+
+ /* check storage space */
+ new_storage = uv->used_storage;
+ if (old_var) {
+ new_storage -= variable_size(old_var);
+ }
+ if (new_var) {
+ new_storage += variable_size(new_var);
+ }
+ if (new_storage > uv->max_storage) {
+ mvar->status = EFI_OUT_OF_RESOURCES;
+ goto rollback;
+ }
+
+ attributes = new_var
+ ? new_var->attributes
+ : old_var->attributes;
+
+ /* all good, commit */
+ del_variable(uv, old_var);
+ uv->used_storage = new_storage;
+
+ if (attributes & EFI_VARIABLE_NON_VOLATILE) {
+ uefi_vars_json_save(uv);
+ }
+
+ mvar->status = EFI_SUCCESS;
+ return sizeof(*mvar);
+
+rollback:
+ del_variable(uv, new_var);
+ return sizeof(*mvar);
+}
+
+static size_t uefi_vars_mm_variable_info(uefi_vars_state *uv, mm_header *mhdr,
+ mm_variable *mvar, void *func)
+{
+ mm_variable_info *vi = func;
+ size_t length;
+
+ length = sizeof(*mvar) + sizeof(*vi);
+ if (uv->buf_size < length) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE);
+ }
+
+ vi->max_storage_size = uv->max_storage;
+ vi->free_storage_size = uv->max_storage - uv->used_storage;
+ vi->max_variable_size = uv->max_storage >> 2;
+ vi->attributes = 0;
+
+ mvar->status = EFI_SUCCESS;
+ return length;
+}
+
+static size_t
+uefi_vars_mm_get_payload_size(uefi_vars_state *uv, mm_header *mhdr,
+ mm_variable *mvar, void *func)
+{
+ mm_get_payload_size *ps = func;
+ size_t length;
+
+ length = sizeof(*mvar) + sizeof(*ps);
+ if (uv->buf_size < length) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE);
+ }
+
+ ps->payload_size = uv->buf_size;
+ mvar->status = EFI_SUCCESS;
+ return length;
+}
+
+static size_t
+uefi_vars_mm_lock_variable(uefi_vars_state *uv, mm_header *mhdr,
+ mm_variable *mvar, void *func)
+{
+ mm_lock_variable *lv = func;
+ variable_policy_entry *pe;
+ uint16_t *name, *dest;
+ size_t length;
+
+ length = sizeof(*mvar) + sizeof(*lv);
+ if (mhdr->length < length) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE);
+ }
+
+ name = func + sizeof(*lv);
+ length += lv->name_size;
+ if (mhdr->length < length) {
+ return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE);
+ }
+
+ uefi_trace_variable(__func__, lv->guid, name, lv->name_size);
+
+ pe = g_malloc0(sizeof(*pe) + lv->name_size);
+ pe->version = VARIABLE_POLICY_ENTRY_REVISION;
+ pe->size = sizeof(*pe) + lv->name_size;
+ pe->offset_to_name = sizeof(*pe);
+ pe->namespace = lv->guid;
+ pe->min_size = 0;
+ pe->max_size = UINT32_MAX;
+ pe->attributes_must_have = 0;
+ pe->attributes_cant_have = 0;
+ pe->lock_policy_type = VARIABLE_POLICY_TYPE_LOCK_NOW;
+
+ dest = (void *)pe + pe->offset_to_name;
+ memcpy(dest, name, lv->name_size);
+
+ uefi_vars_add_policy(uv, pe);
+ g_free(pe);
+
+ mvar->status = EFI_SUCCESS;
+ return length;
+}
+
+uint32_t uefi_vars_mm_vars_proto(uefi_vars_state *uv)
+{
+ static const char *fnames[] = {
+ "zero",
+ "get-variable",
+ "get-next-variable-name",
+ "set-variable",
+ "query-variable-info",
+ "ready-to-boot",
+ "exit-boot-service",
+ "get-statistics",
+ "lock-variable",
+ "var-check-prop-set",
+ "var-check-prop-get",
+ "get-payload-size",
+ "init-runtime-cache-contect",
+ "sync-runtime-cache",
+ "get-runtime-cache-info",
+ };
+ const char *fname;
+ size_t length;
+
+ mm_header *mhdr = (mm_header *) uv->buffer;
+ mm_variable *mvar = (mm_variable *) (uv->buffer + sizeof(*mhdr));
+ void *func = (uv->buffer + sizeof(*mhdr) + sizeof(*mvar));
+
+ if (mhdr->length < sizeof(*mvar)) {
+ return UEFI_VARS_STS_ERR_BAD_BUFFER_SIZE;
+ }
+
+ fname = mvar->function < ARRAY_SIZE(fnames)
+ ? fnames[mvar->function]
+ : "unknown";
+ trace_uefi_vars_proto_cmd(fname);
+
+ switch (mvar->function) {
+ case SMM_VARIABLE_FUNCTION_GET_VARIABLE:
+ length = uefi_vars_mm_get_variable(uv, mhdr, mvar, func);
+ break;
+
+ case SMM_VARIABLE_FUNCTION_GET_NEXT_VARIABLE_NAME:
+ length = uefi_vars_mm_get_next_variable(uv, mhdr, mvar, func);
+ break;
+
+ case SMM_VARIABLE_FUNCTION_SET_VARIABLE:
+ length = uefi_vars_mm_set_variable(uv, mhdr, mvar, func);
+ break;
+
+ case SMM_VARIABLE_FUNCTION_QUERY_VARIABLE_INFO:
+ length = uefi_vars_mm_variable_info(uv, mhdr, mvar, func);
+ break;
+
+ case SMM_VARIABLE_FUNCTION_LOCK_VARIABLE:
+ length = uefi_vars_mm_lock_variable(uv, mhdr, mvar, func);
+ break;
+
+ case SMM_VARIABLE_FUNCTION_GET_PAYLOAD_SIZE:
+ length = uefi_vars_mm_get_payload_size(uv, mhdr, mvar, func);
+ break;
+
+ case SMM_VARIABLE_FUNCTION_READY_TO_BOOT:
+ trace_uefi_event("ready-to-boot");
+ uv->ready_to_boot = true;
+ length = 0;
+ break;
+
+ case SMM_VARIABLE_FUNCTION_EXIT_BOOT_SERVICE:
+ trace_uefi_event("exit-boot-service");
+ uv->exit_boot_service = true;
+ length = 0;
+ break;
+
+ default:
+ length = uefi_vars_mm_error(mhdr, mvar, EFI_UNSUPPORTED);
+ break;
+ }
+
+ if (mhdr->length < length) {
+ mvar->status = EFI_BUFFER_TOO_SMALL;
+ }
+
+ uefi_trace_status(__func__, mvar->status);
+ return UEFI_VARS_STS_SUCCESS;
+}
--
2.41.0© 2016 - 2024 Red Hat, Inc.