This is the uefi variable service (EfiSmmVariableProtocol), providing functions for listing, reading and updating variables.
Signed-off-by: Gerd Hoffmann <kra...@redhat.com> --- hw/uefi/var-service-vars.c | 725 +++++++++++++++++++++++++++++++++++++ 1 file changed, 725 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..7f98d77a38d1 --- /dev/null +++ b/hw/uefi/var-service-vars.c @@ -0,0 +1,725 @@ +/* + * SPDX-License-Identifier: GPL-2.0-or-later + * + * uefi vars device - EfiSmmVariableProtocol implementation + */ +#include "qemu/osdep.h" +#include "qemu/error-report.h" +#include "system/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" + +#define EFI_VARIABLE_ATTRIBUTE_SUPPORTED \ + (EFI_VARIABLE_NON_VOLATILE | \ + EFI_VARIABLE_BOOTSERVICE_ACCESS | \ + EFI_VARIABLE_RUNTIME_ACCESS | \ + EFI_VARIABLE_HARDWARE_ERROR_RECORD | \ + EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS | \ + EFI_VARIABLE_APPEND_WRITE) + + +const VMStateDescription vmstate_uefi_time = { + .name = "uefi-time", + .fields = (VMStateField[]) { + VMSTATE_UINT16(year, efi_time), + VMSTATE_UINT8(month, efi_time), + VMSTATE_UINT8(day, efi_time), + VMSTATE_UINT8(hour, efi_time), + VMSTATE_UINT8(minute, efi_time), + VMSTATE_UINT8(second, efi_time), + VMSTATE_UINT32(nanosecond, efi_time), + VMSTATE_END_OF_LIST() + }, +}; + +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_STRUCT(time, uefi_variable, 0, vmstate_uefi_time, efi_time), + 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; + } + if (!var->data_size) { + /* in process of being created/updated */ + 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; + + var->attributes &= ~EFI_VARIABLE_APPEND_WRITE; + + 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->digest); + 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; + size += var->digest_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 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 (new_var) { + if (new_var->attributes & ~EFI_VARIABLE_ATTRIBUTE_SUPPORTED) { + return EFI_UNSUPPORTED; + } + 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 { + /* delete */ + g_assert(old_var); + status = uefi_vars_policy_check(uv, old_var, false); + } + if (status != EFI_SUCCESS) { + return status; + } + + status = uefi_vars_check_secure_boot(uv, new_var ?: old_var); + if (status != EFI_SUCCESS) { + return status; + } + + return EFI_SUCCESS; +} + +static void append_write(uefi_variable *old_var, + uefi_variable *new_var) +{ + uefi_vars_siglist siglist; + uint64_t size; + void *data; + + uefi_vars_siglist_init(&siglist); + uefi_vars_siglist_parse(&siglist, old_var->data, old_var->data_size); + uefi_vars_siglist_parse(&siglist, new_var->data, new_var->data_size); + + size = uefi_vars_siglist_blob_size(&siglist); + data = g_malloc(size); + uefi_vars_siglist_blob_generate(&siglist, data, size); + + g_free(new_var->data); + new_var->data = data; + new_var->data_size = size; + + uefi_vars_siglist_free(&siglist); +} + +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; + uint64_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); + if (uadd64_overflow(length, va->name_size, &length)) { + return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE); + } + if (mhdr->length < length) { + return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE); + } + + if (!uefi_str_is_valid(name, va->name_size, true)) { + return uefi_vars_mm_error(mhdr, mvar, EFI_INVALID_PARAMETER); + } + + 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; + if (uadd64_overflow(length, va->data_size, &length)) { + return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE); + } + if (uv->buf_size < length) { + return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE); + } + + va->attributes = var->attributes; + if (va->data_size < var->data_size) { + va->data_size = var->data_size; + length -= va->data_size; + mvar->status = EFI_BUFFER_TOO_SMALL; + } else { + 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; + uint64_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); + if (uadd64_overflow(length, nv->name_size, &length)) { + return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE); + } + if (mhdr->length < length) { + return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE); + } + + if (!uefi_str_is_valid(name, nv->name_size, true)) { + return uefi_vars_mm_error(mhdr, mvar, EFI_INVALID_PARAMETER); + } + + 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 bool uefi_vars_mm_digest_compare(uefi_variable *old_var, + uefi_variable *new_var) +{ + if (!old_var->digest || + !new_var->digest || + !old_var->digest_size || + !new_var->digest_size) { + /* should not happen */ + trace_uefi_vars_security_violation("inconsistent authvar digest state"); + return false; + } + if (old_var->digest_size != new_var->digest_size) { + trace_uefi_vars_security_violation("authvar digest size mismatch"); + return false; + } + if (memcmp(old_var->digest, new_var->digest, + old_var->digest_size) != 0) { + trace_uefi_vars_security_violation("authvar digest data mismatch"); + return false; + } + return true; +} + +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; + uint64_t length; + size_t 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); + if (uadd64_overflow(length, va->name_size, &length)) { + return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE); + } + if (mhdr->length < length) { + return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_SIZE); + } + + data = func + sizeof(*va) + va->name_size; + if (uadd64_overflow(length, va->data_size, &length)) { + return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_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); + + if (!uefi_str_is_valid(name, va->name_size, true)) { + return uefi_vars_mm_error(mhdr, mvar, EFI_INVALID_PARAMETER); + } + + 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); + if (va->attributes & EFI_VARIABLE_AUTHENTICATED_WRITE_ACCESS) { + /* not implemented (deprecated in uefi spec) */ + warn_report("%s: AUTHENTICATED_WRITE_ACCESS", __func__); + mvar->status = EFI_UNSUPPORTED; + goto rollback; + } else if (va->attributes & + EFI_VARIABLE_TIME_BASED_AUTHENTICATED_WRITE_ACCESS) { + status = uefi_vars_check_auth_2(uv, new_var, va, data); + if (status != EFI_SUCCESS) { + mvar->status = status; + goto rollback; + } + if (old_var && new_var) { + if (uefi_time_compare(&old_var->time, &new_var->time) > 0) { + trace_uefi_vars_security_violation("time check failed"); + mvar->status = EFI_SECURITY_VIOLATION; + goto rollback; + } + if (old_var->digest_size || new_var->digest_size) { + if (!uefi_vars_mm_digest_compare(old_var, new_var)) { + mvar->status = EFI_SECURITY_VIOLATION; + goto rollback; + } + } + } + } else { + new_var->data = g_malloc(va->data_size); + memcpy(new_var->data, data, va->data_size); + new_var->data_size = va->data_size; + } + if (!new_var->data) { + /* we land here when deleting authenticated variables */ + del_variable(uv, new_var); + new_var = NULL; + } + } 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; + } + + if (va->attributes & EFI_VARIABLE_APPEND_WRITE && old_var && new_var) { + /* merge signature databases */ + if (!uefi_vars_is_sb_any(new_var)) { + mvar->status = EFI_UNSUPPORTED; + goto rollback; + } + append_write(old_var, new_var); + } + + /* 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); + } + + if (new_var && uefi_vars_is_sb_pk(new_var)) { + uefi_vars_auth_init(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; + uint64_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; + uint64_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; + uint64_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); + if (uadd64_overflow(length, lv->name_size, &length)) { + return uefi_vars_mm_error(mhdr, mvar, EFI_BAD_BUFFER_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; + uint64_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; +} -- 2.48.1