| 1 | /* |
| 2 | * SPDX-License-Identifier: GPL-2.0-or-later |
| 3 | * |
| 4 | * uefi vars device - VarCheckPolicyLibMmiHandler implementation |
| 5 | * |
| 6 | * variable policy specs: |
| 7 | * https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Library/VariablePolicyLib/ReadMe.md |
| 8 | */ |
| 9 | #include "qemu/osdep.h" |
| 10 | #include "qemu/error-report.h" |
| 11 | #include "system/dma.h" |
| 12 | #include "migration/vmstate.h" |
| 13 | |
| 14 | #include "hw/uefi/var-service.h" |
| 15 | #include "hw/uefi/var-service-api.h" |
| 16 | #include "hw/uefi/var-service-edk2.h" |
| 17 | |
| 18 | #include "trace.h" |
| 19 | |
| 20 | static int check_calc_policy(uefi_var_policy *pol); |
| 21 | |
| 22 | static int uefi_var_policy_post_load(void *opaque, int version_id) |
| 23 | { |
| 24 | uefi_var_policy *pol = opaque; |
| 25 | int rc; |
| 26 | |
| 27 | rc = check_calc_policy(pol); |
| 28 | if (rc != 0) { |
| 29 | error_report("invalid uefi variable policy"); |
| 30 | } |
| 31 | return rc; |
| 32 | } |
| 33 | |
| 34 | const VMStateDescription vmstate_uefi_var_policy = { |
| 35 | .name = "uefi-var-policy", |
| 36 | .post_load = uefi_var_policy_post_load, |
| 37 | .fields = (VMStateField[]) { |
| 38 | VMSTATE_UINT32(entry_size, uefi_var_policy), |
| 39 | VMSTATE_VBUFFER_ALLOC_UINT32(entry, uefi_var_policy, |
| 40 | 0, NULL, entry_size), |
| 41 | VMSTATE_END_OF_LIST() |
| 42 | }, |
| 43 | }; |
| 44 | |
| 45 | static gboolean wildcard_str_equal(uefi_var_policy *pol, |
| 46 | uefi_variable *var) |
| 47 | { |
| 48 | return uefi_str_equal_ex(pol->name, pol->name_size, |
| 49 | var->name, var->name_size, |
| 50 | true); |
| 51 | } |
| 52 | |
| 53 | static uefi_var_policy *find_policy(uefi_vars_state *uv, QemuUUID guid, |
| 54 | uint16_t *name, uint64_t name_size) |
| 55 | { |
| 56 | uefi_var_policy *pol; |
| 57 | |
| 58 | QTAILQ_FOREACH(pol, &uv->var_policies, next) { |
| 59 | if (!qemu_uuid_is_equal(&pol->entry->namespace, &guid)) { |
| 60 | continue; |
| 61 | } |
| 62 | if (!uefi_str_equal(pol->name, pol->name_size, |
| 63 | name, name_size)) { |
| 64 | continue; |
| 65 | } |
| 66 | return pol; |
| 67 | } |
| 68 | return NULL; |
| 69 | } |
| 70 | |
| 71 | static uefi_var_policy *wildcard_find_policy(uefi_vars_state *uv, |
| 72 | uefi_variable *var) |
| 73 | { |
| 74 | uefi_var_policy *pol; |
| 75 | |
| 76 | QTAILQ_FOREACH(pol, &uv->var_policies, next) { |
| 77 | if (!qemu_uuid_is_equal(&pol->entry->namespace, &var->guid)) { |
| 78 | continue; |
| 79 | } |
| 80 | if (!wildcard_str_equal(pol, var)) { |
| 81 | continue; |
| 82 | } |
| 83 | return pol; |
| 84 | } |
| 85 | return NULL; |
| 86 | } |
| 87 | |
| 88 | static int check_calc_policy(uefi_var_policy *pol) |
| 89 | { |
| 90 | variable_policy_entry *pe = pol->entry; |
| 91 | unsigned int i; |
| 92 | |
| 93 | if (pol->entry_size != pe->size || |
| 94 | pe->offset_to_name >= pe->size) { |
| 95 | return -1; |
| 96 | } |
| 97 | |
| 98 | pol->name = (void *)pol->entry + pe->offset_to_name; |
| 99 | pol->name_size = pe->size - pe->offset_to_name; |
| 100 | |
| 101 | if (!uefi_str_is_valid(pol->name, pol->name_size, false)) { |
| 102 | return -1; |
| 103 | } |
| 104 | |
| 105 | for (i = 0; i < pol->name_size / 2; i++) { |
| 106 | if (pol->name[i] == '#') { |
| 107 | pol->hashmarks++; |
| 108 | } |
| 109 | } |
| 110 | |
| 111 | return 0; |
| 112 | } |
| 113 | |
| 114 | uefi_var_policy *uefi_vars_add_policy(uefi_vars_state *uv, |
| 115 | variable_policy_entry *pe) |
| 116 | { |
| 117 | uefi_var_policy *pol, *p; |
| 118 | int rc; |
| 119 | |
| 120 | pol = g_new0(uefi_var_policy, 1); |
| 121 | pol->entry = g_malloc(pe->size); |
| 122 | memcpy(pol->entry, pe, pe->size); |
| 123 | pol->entry_size = pe->size; |
| 124 | |
| 125 | rc = check_calc_policy(pol); |
| 126 | g_assert(rc == 0); |
| 127 | |
| 128 | /* keep list sorted by priority, add to tail of priority group */ |
| 129 | QTAILQ_FOREACH(p, &uv->var_policies, next) { |
| 130 | if ((p->hashmarks > pol->hashmarks) || |
| 131 | (!p->name_size && pol->name_size)) { |
| 132 | QTAILQ_INSERT_BEFORE(p, pol, next); |
| 133 | return pol; |
| 134 | } |
| 135 | } |
| 136 | |
| 137 | QTAILQ_INSERT_TAIL(&uv->var_policies, pol, next); |
| 138 | return pol; |
| 139 | } |
| 140 | |
| 141 | efi_status uefi_vars_policy_check(uefi_vars_state *uv, |
| 142 | uefi_variable *var, |
| 143 | gboolean is_newvar) |
| 144 | { |
| 145 | uefi_var_policy *pol; |
| 146 | variable_policy_entry *pe; |
| 147 | variable_lock_on_var_state *lvarstate; |
| 148 | uint16_t *lvarname; |
| 149 | size_t lvarnamesize; |
| 150 | uefi_variable *lvar; |
| 151 | |
| 152 | if (!uv->end_of_dxe) { |
| 153 | return EFI_SUCCESS; |
| 154 | } |
| 155 | |
| 156 | pol = wildcard_find_policy(uv, var); |
| 157 | if (!pol) { |
| 158 | return EFI_SUCCESS; |
| 159 | } |
| 160 | pe = pol->entry; |
| 161 | |
| 162 | uefi_trace_variable(__func__, var->guid, var->name, var->name_size); |
| 163 | |
| 164 | if ((var->attributes & pe->attributes_must_have) != pe->attributes_must_have) { |
| 165 | trace_uefi_vars_policy_deny("must-have-attr"); |
| 166 | return EFI_INVALID_PARAMETER; |
| 167 | } |
| 168 | if ((var->attributes & pe->attributes_cant_have) != 0) { |
| 169 | trace_uefi_vars_policy_deny("cant-have-attr"); |
| 170 | return EFI_INVALID_PARAMETER; |
| 171 | } |
| 172 | |
| 173 | if (var->data_size < pe->min_size) { |
| 174 | trace_uefi_vars_policy_deny("min-size"); |
| 175 | return EFI_INVALID_PARAMETER; |
| 176 | } |
| 177 | if (var->data_size > pe->max_size) { |
| 178 | trace_uefi_vars_policy_deny("max-size"); |
| 179 | return EFI_INVALID_PARAMETER; |
| 180 | } |
| 181 | |
| 182 | switch (pe->lock_policy_type) { |
| 183 | case VARIABLE_POLICY_TYPE_NO_LOCK: |
| 184 | break; |
| 185 | |
| 186 | case VARIABLE_POLICY_TYPE_LOCK_NOW: |
| 187 | trace_uefi_vars_policy_deny("lock-now"); |
| 188 | return EFI_WRITE_PROTECTED; |
| 189 | |
| 190 | case VARIABLE_POLICY_TYPE_LOCK_ON_CREATE: |
| 191 | if (!is_newvar) { |
| 192 | trace_uefi_vars_policy_deny("lock-on-create"); |
| 193 | return EFI_WRITE_PROTECTED; |
| 194 | } |
| 195 | break; |
| 196 | |
| 197 | case VARIABLE_POLICY_TYPE_LOCK_ON_VAR_STATE: |
| 198 | lvarstate = (void *)pol->entry + sizeof(*pe); |
| 199 | lvarname = (void *)pol->entry + sizeof(*pe) + sizeof(*lvarstate); |
| 200 | lvarnamesize = pe->offset_to_name - sizeof(*pe) - sizeof(*lvarstate); |
| 201 | |
| 202 | uefi_trace_variable(__func__, lvarstate->namespace, |
| 203 | lvarname, lvarnamesize); |
| 204 | lvar = uefi_vars_find_variable(uv, lvarstate->namespace, |
| 205 | lvarname, lvarnamesize); |
| 206 | if (lvar && lvar->data_size == 1) { |
| 207 | uint8_t *value = lvar->data; |
| 208 | if (lvarstate->value == *value) { |
| 209 | return EFI_WRITE_PROTECTED; |
| 210 | } |
| 211 | } |
| 212 | break; |
| 213 | } |
| 214 | |
| 215 | return EFI_SUCCESS; |
| 216 | } |
| 217 | |
| 218 | void uefi_vars_policies_clear(uefi_vars_state *uv) |
| 219 | { |
| 220 | uefi_var_policy *pol; |
| 221 | |
| 222 | while (!QTAILQ_EMPTY(&uv->var_policies)) { |
| 223 | pol = QTAILQ_FIRST(&uv->var_policies); |
| 224 | QTAILQ_REMOVE(&uv->var_policies, pol, next); |
| 225 | g_free(pol->entry); |
| 226 | g_free(pol); |
| 227 | } |
| 228 | } |
| 229 | |
| 230 | static size_t uefi_vars_mm_policy_error(mm_header *mhdr, |
| 231 | mm_check_policy *mchk, |
| 232 | uint64_t status) |
| 233 | { |
| 234 | mchk->result = status; |
| 235 | return sizeof(*mchk); |
| 236 | } |
| 237 | |
| 238 | static uint32_t uefi_vars_mm_check_policy_is_enabled(uefi_vars_state *uv, |
| 239 | mm_header *mhdr, |
| 240 | mm_check_policy *mchk, |
| 241 | void *func) |
| 242 | { |
| 243 | mm_check_policy_is_enabled *mpar = func; |
| 244 | size_t length; |
| 245 | |
| 246 | length = sizeof(*mchk) + sizeof(*mpar); |
| 247 | if (mhdr->length < length) { |
| 248 | return uefi_vars_mm_policy_error(mhdr, mchk, EFI_BAD_BUFFER_SIZE); |
| 249 | } |
| 250 | |
| 251 | mpar->state = TRUE; |
| 252 | mchk->result = EFI_SUCCESS; |
| 253 | return sizeof(*mchk); |
| 254 | } |
| 255 | |
| 256 | static uint32_t uefi_vars_mm_check_policy_register(uefi_vars_state *uv, |
| 257 | mm_header *mhdr, |
| 258 | mm_check_policy *mchk, |
| 259 | void *func) |
| 260 | { |
| 261 | variable_policy_entry *pe = func; |
| 262 | uefi_var_policy *pol; |
| 263 | uint64_t length; |
| 264 | |
| 265 | if (mhdr->length < sizeof(*mchk) + sizeof(*pe)) { |
| 266 | return uefi_vars_mm_policy_error(mhdr, mchk, EFI_BAD_BUFFER_SIZE); |
| 267 | } |
| 268 | if (uadd64_overflow(sizeof(*mchk), pe->size, &length)) { |
| 269 | return uefi_vars_mm_policy_error(mhdr, mchk, EFI_BAD_BUFFER_SIZE); |
| 270 | } |
| 271 | if (mhdr->length < length) { |
| 272 | return uefi_vars_mm_policy_error(mhdr, mchk, EFI_BAD_BUFFER_SIZE); |
| 273 | } |
| 274 | if (pe->size < sizeof(*pe)) { |
| 275 | return uefi_vars_mm_policy_error(mhdr, mchk, EFI_BAD_BUFFER_SIZE); |
| 276 | } |
| 277 | if (pe->offset_to_name < sizeof(*pe)) { |
| 278 | return uefi_vars_mm_policy_error(mhdr, mchk, EFI_BAD_BUFFER_SIZE); |
| 279 | } |
| 280 | |
| 281 | if (pe->lock_policy_type == VARIABLE_POLICY_TYPE_LOCK_ON_VAR_STATE && |
| 282 | pe->offset_to_name < sizeof(*pe) + sizeof(variable_lock_on_var_state)) { |
| 283 | return uefi_vars_mm_policy_error(mhdr, mchk, EFI_BAD_BUFFER_SIZE); |
| 284 | } |
| 285 | |
| 286 | /* check space for minimum string length */ |
| 287 | if (pe->size < (size_t)pe->offset_to_name) { |
| 288 | return uefi_vars_mm_policy_error(mhdr, mchk, EFI_BAD_BUFFER_SIZE); |
| 289 | } |
| 290 | |
| 291 | if (!uefi_str_is_valid((void *)pe + pe->offset_to_name, |
| 292 | pe->size - pe->offset_to_name, |
| 293 | false)) { |
| 294 | return uefi_vars_mm_policy_error(mhdr, mchk, EFI_INVALID_PARAMETER); |
| 295 | } |
| 296 | |
| 297 | pol = find_policy(uv, pe->namespace, |
| 298 | (void *)pe + pe->offset_to_name, |
| 299 | pe->size - pe->offset_to_name); |
| 300 | if (pol) { |
| 301 | return uefi_vars_mm_policy_error(mhdr, mchk, EFI_ALREADY_STARTED); |
| 302 | } |
| 303 | |
| 304 | if (uv->used_storage + pe->size > uv->max_storage) { |
| 305 | return uefi_vars_mm_policy_error(mhdr, mchk, EFI_OUT_OF_RESOURCES); |
| 306 | } |
| 307 | |
| 308 | uefi_vars_add_policy(uv, pe); |
| 309 | uv->used_storage += pe->size; |
| 310 | |
| 311 | mchk->result = EFI_SUCCESS; |
| 312 | return sizeof(*mchk); |
| 313 | } |
| 314 | |
| 315 | uint32_t uefi_vars_mm_check_policy_proto(uefi_vars_state *uv) |
| 316 | { |
| 317 | static const char *fnames[] = { |
| 318 | "zero", |
| 319 | "disable", |
| 320 | "is-enabled", |
| 321 | "register", |
| 322 | "dump", |
| 323 | "lock", |
| 324 | }; |
| 325 | const char *fname; |
| 326 | mm_header *mhdr = (mm_header *) uv->buffer; |
| 327 | mm_check_policy *mchk = (mm_check_policy *) (uv->buffer + sizeof(*mhdr)); |
| 328 | void *func = (uv->buffer + sizeof(*mhdr) + sizeof(*mchk)); |
| 329 | |
| 330 | if (mhdr->length < sizeof(*mchk)) { |
| 331 | return UEFI_VARS_STS_ERR_BAD_BUFFER_SIZE; |
| 332 | } |
| 333 | |
| 334 | fname = mchk->command < ARRAY_SIZE(fnames) |
| 335 | ? fnames[mchk->command] |
| 336 | : "unknown"; |
| 337 | trace_uefi_vars_policy_cmd(fname); |
| 338 | |
| 339 | switch (mchk->command) { |
| 340 | case VAR_CHECK_POLICY_COMMAND_DISABLE: |
| 341 | mchk->result = EFI_UNSUPPORTED; |
| 342 | break; |
| 343 | case VAR_CHECK_POLICY_COMMAND_IS_ENABLED: |
| 344 | uefi_vars_mm_check_policy_is_enabled(uv, mhdr, mchk, func); |
| 345 | break; |
| 346 | case VAR_CHECK_POLICY_COMMAND_REGISTER: |
| 347 | if (uv->policy_locked) { |
| 348 | mchk->result = EFI_WRITE_PROTECTED; |
| 349 | } else { |
| 350 | uefi_vars_mm_check_policy_register(uv, mhdr, mchk, func); |
| 351 | } |
| 352 | break; |
| 353 | case VAR_CHECK_POLICY_COMMAND_LOCK: |
| 354 | uv->policy_locked = true; |
| 355 | mchk->result = EFI_SUCCESS; |
| 356 | break; |
| 357 | default: |
| 358 | mchk->result = EFI_UNSUPPORTED; |
| 359 | break; |
| 360 | } |
| 361 | |
| 362 | uefi_trace_status(__func__, mchk->result); |
| 363 | return UEFI_VARS_STS_SUCCESS; |
| 364 | } |