1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * File interface for UEFI variables
4 *
5 * Copyright (c) 2020, Heinrich Schuchardt
6 */
7
8 #include <common.h>
9 #include <efi_loader.h>
10 #include <efi_variable.h>
11 #include <u-boot/crc.h>
12
13 /*
14 * The variables efi_var_file and efi_var_entry must be static to avoid
15 * referencing them via the global offset table (section .got). The GOT
16 * is neither mapped as EfiRuntimeServicesData nor do we support its
17 * relocation during SetVirtualAddressMap().
18 */
19 static struct efi_var_file __efi_runtime_data *efi_var_buf;
20 static struct efi_var_entry __efi_runtime_data *efi_current_var;
21
22 /**
23 * efi_var_mem_compare() - compare GUID and name with a variable
24 *
25 * @var: variable to compare
26 * @guid: GUID to compare
27 * @name: variable name to compare
28 * @next: pointer to next variable
29 * Return: true if match
30 */
31 static bool __efi_runtime
efi_var_mem_compare(struct efi_var_entry * var,const efi_guid_t * guid,const u16 * name,struct efi_var_entry ** next)32 efi_var_mem_compare(struct efi_var_entry *var, const efi_guid_t *guid,
33 const u16 *name, struct efi_var_entry **next)
34 {
35 int i;
36 u8 *guid1, *guid2;
37 const u16 *data, *var_name;
38 bool match = true;
39
40 for (guid1 = (u8 *)&var->guid, guid2 = (u8 *)guid, i = 0;
41 i < sizeof(efi_guid_t) && match; ++i)
42 match = (guid1[i] == guid2[i]);
43
44 for (data = var->name, var_name = name;; ++data, ++var_name) {
45 if (match)
46 match = (*data == *var_name);
47 if (!*data)
48 break;
49 }
50
51 ++data;
52
53 if (next)
54 *next = (struct efi_var_entry *)
55 ALIGN((uintptr_t)data + var->length, 8);
56
57 if (match)
58 efi_current_var = var;
59
60 return match;
61 }
62
63 struct efi_var_entry __efi_runtime
efi_var_mem_find(const efi_guid_t * guid,const u16 * name,struct efi_var_entry ** next)64 *efi_var_mem_find(const efi_guid_t *guid, const u16 *name,
65 struct efi_var_entry **next)
66 {
67 struct efi_var_entry *var, *last;
68
69 last = (struct efi_var_entry *)
70 ((uintptr_t)efi_var_buf + efi_var_buf->length);
71
72 if (!*name) {
73 if (next) {
74 *next = efi_var_buf->var;
75 if (*next >= last)
76 *next = NULL;
77 }
78 return NULL;
79 }
80 if (efi_current_var &&
81 efi_var_mem_compare(efi_current_var, guid, name, next)) {
82 if (next && *next >= last)
83 *next = NULL;
84 return efi_current_var;
85 }
86
87 var = efi_var_buf->var;
88 if (var < last) {
89 for (; var;) {
90 struct efi_var_entry *pos;
91 bool match;
92
93 match = efi_var_mem_compare(var, guid, name, &pos);
94 if (pos >= last)
95 pos = NULL;
96 if (match) {
97 if (next)
98 *next = pos;
99 return var;
100 }
101 var = pos;
102 }
103 }
104 if (next)
105 *next = NULL;
106 return NULL;
107 }
108
efi_var_mem_del(struct efi_var_entry * var)109 void __efi_runtime efi_var_mem_del(struct efi_var_entry *var)
110 {
111 u16 *data;
112 struct efi_var_entry *next, *last;
113
114 if (!var)
115 return;
116
117 last = (struct efi_var_entry *)
118 ((uintptr_t)efi_var_buf + efi_var_buf->length);
119 if (var <= efi_current_var)
120 efi_current_var = NULL;
121
122 for (data = var->name; *data; ++data)
123 ;
124 ++data;
125 next = (struct efi_var_entry *)
126 ALIGN((uintptr_t)data + var->length, 8);
127 efi_var_buf->length -= (uintptr_t)next - (uintptr_t)var;
128
129 /* efi_memcpy_runtime() can be used because next >= var. */
130 efi_memcpy_runtime(var, next, (uintptr_t)last - (uintptr_t)next);
131 efi_var_buf->crc32 = crc32(0, (u8 *)efi_var_buf->var,
132 efi_var_buf->length -
133 sizeof(struct efi_var_file));
134 }
135
efi_var_mem_ins(u16 * variable_name,const efi_guid_t * vendor,u32 attributes,const efi_uintn_t size1,const void * data1,const efi_uintn_t size2,const void * data2,const u64 time)136 efi_status_t __efi_runtime efi_var_mem_ins(
137 u16 *variable_name,
138 const efi_guid_t *vendor, u32 attributes,
139 const efi_uintn_t size1, const void *data1,
140 const efi_uintn_t size2, const void *data2,
141 const u64 time)
142 {
143 u16 *data;
144 struct efi_var_entry *var;
145 u32 var_name_len;
146
147 var = (struct efi_var_entry *)
148 ((uintptr_t)efi_var_buf + efi_var_buf->length);
149 for (var_name_len = 0; variable_name[var_name_len]; ++var_name_len)
150 ;
151 ++var_name_len;
152 data = var->name + var_name_len;
153
154 if ((uintptr_t)data - (uintptr_t)efi_var_buf + size1 + size2 >
155 EFI_VAR_BUF_SIZE)
156 return EFI_OUT_OF_RESOURCES;
157
158 var->attr = attributes;
159 var->length = size1 + size2;
160 var->time = time;
161
162 efi_memcpy_runtime(&var->guid, vendor, sizeof(efi_guid_t));
163 efi_memcpy_runtime(var->name, variable_name,
164 sizeof(u16) * var_name_len);
165 efi_memcpy_runtime(data, data1, size1);
166 efi_memcpy_runtime((u8 *)data + size1, data2, size2);
167
168 var = (struct efi_var_entry *)
169 ALIGN((uintptr_t)data + var->length, 8);
170 efi_var_buf->length = (uintptr_t)var - (uintptr_t)efi_var_buf;
171 efi_var_buf->crc32 = crc32(0, (u8 *)efi_var_buf->var,
172 efi_var_buf->length -
173 sizeof(struct efi_var_file));
174
175 return EFI_SUCCESS;
176 }
177
efi_var_mem_free(void)178 u64 __efi_runtime efi_var_mem_free(void)
179 {
180 return EFI_VAR_BUF_SIZE - efi_var_buf->length -
181 sizeof(struct efi_var_entry);
182 }
183
184 /**
185 * efi_var_mem_bs_del() - delete boot service only variables
186 */
efi_var_mem_bs_del(void)187 static void efi_var_mem_bs_del(void)
188 {
189 struct efi_var_entry *var = efi_var_buf->var;
190
191 for (;;) {
192 struct efi_var_entry *last;
193
194 last = (struct efi_var_entry *)
195 ((uintptr_t)efi_var_buf + efi_var_buf->length);
196 if (var >= last)
197 break;
198 if (var->attr & EFI_VARIABLE_RUNTIME_ACCESS) {
199 u16 *data;
200
201 /* skip variable */
202 for (data = var->name; *data; ++data)
203 ;
204 ++data;
205 var = (struct efi_var_entry *)
206 ALIGN((uintptr_t)data + var->length, 8);
207 } else {
208 /* delete variable */
209 efi_var_mem_del(var);
210 }
211 }
212 }
213
214 /**
215 * efi_var_mem_notify_exit_boot_services() - ExitBootService callback
216 *
217 * @event: callback event
218 * @context: callback context
219 */
220 static void EFIAPI
efi_var_mem_notify_exit_boot_services(struct efi_event * event,void * context)221 efi_var_mem_notify_exit_boot_services(struct efi_event *event, void *context)
222 {
223 EFI_ENTRY("%p, %p", event, context);
224
225 /* Delete boot service only variables */
226 efi_var_mem_bs_del();
227
228 EFI_EXIT(EFI_SUCCESS);
229 }
230
231 /**
232 * efi_var_mem_notify_exit_boot_services() - SetVirtualMemoryMap callback
233 *
234 * @event: callback event
235 * @context: callback context
236 */
237 static void EFIAPI __efi_runtime
efi_var_mem_notify_virtual_address_map(struct efi_event * event,void * context)238 efi_var_mem_notify_virtual_address_map(struct efi_event *event, void *context)
239 {
240 efi_convert_pointer(0, (void **)&efi_var_buf);
241 efi_current_var = NULL;
242 }
243
efi_var_mem_init(void)244 efi_status_t efi_var_mem_init(void)
245 {
246 u64 memory;
247 efi_status_t ret;
248 struct efi_event *event;
249
250 ret = efi_allocate_pages(EFI_ALLOCATE_ANY_PAGES,
251 EFI_RUNTIME_SERVICES_DATA,
252 efi_size_in_pages(EFI_VAR_BUF_SIZE),
253 &memory);
254 if (ret != EFI_SUCCESS)
255 return ret;
256 efi_var_buf = (struct efi_var_file *)(uintptr_t)memory;
257 memset(efi_var_buf, 0, EFI_VAR_BUF_SIZE);
258 efi_var_buf->magic = EFI_VAR_FILE_MAGIC;
259 efi_var_buf->length = (uintptr_t)efi_var_buf->var -
260 (uintptr_t)efi_var_buf;
261 /* crc32 for 0 bytes = 0 */
262
263 ret = efi_create_event(EVT_SIGNAL_EXIT_BOOT_SERVICES, TPL_CALLBACK,
264 efi_var_mem_notify_exit_boot_services, NULL,
265 NULL, &event);
266 if (ret != EFI_SUCCESS)
267 return ret;
268 ret = efi_create_event(EVT_SIGNAL_VIRTUAL_ADDRESS_CHANGE, TPL_CALLBACK,
269 efi_var_mem_notify_virtual_address_map, NULL,
270 NULL, &event);
271 if (ret != EFI_SUCCESS)
272 return ret;
273 return ret;
274 }
275
276 efi_status_t __efi_runtime
efi_get_variable_mem(u16 * variable_name,const efi_guid_t * vendor,u32 * attributes,efi_uintn_t * data_size,void * data,u64 * timep)277 efi_get_variable_mem(u16 *variable_name, const efi_guid_t *vendor, u32 *attributes,
278 efi_uintn_t *data_size, void *data, u64 *timep)
279 {
280 efi_uintn_t old_size;
281 struct efi_var_entry *var;
282 u16 *pdata;
283
284 if (!variable_name || !vendor || !data_size)
285 return EFI_INVALID_PARAMETER;
286 var = efi_var_mem_find(vendor, variable_name, NULL);
287 if (!var)
288 return EFI_NOT_FOUND;
289
290 if (attributes)
291 *attributes = var->attr;
292 if (timep)
293 *timep = var->time;
294
295 old_size = *data_size;
296 *data_size = var->length;
297 if (old_size < var->length)
298 return EFI_BUFFER_TOO_SMALL;
299
300 if (!data)
301 return EFI_INVALID_PARAMETER;
302
303 for (pdata = var->name; *pdata; ++pdata)
304 ;
305 ++pdata;
306
307 efi_memcpy_runtime(data, pdata, var->length);
308
309 return EFI_SUCCESS;
310 }
311
312 efi_status_t __efi_runtime
efi_get_next_variable_name_mem(efi_uintn_t * variable_name_size,u16 * variable_name,efi_guid_t * vendor)313 efi_get_next_variable_name_mem(efi_uintn_t *variable_name_size,
314 u16 *variable_name, efi_guid_t *vendor)
315 {
316 struct efi_var_entry *var;
317 efi_uintn_t old_size;
318 u16 *pdata;
319
320 if (!variable_name_size || !variable_name || !vendor)
321 return EFI_INVALID_PARAMETER;
322
323 if (u16_strnlen(variable_name, *variable_name_size) ==
324 *variable_name_size)
325 return EFI_INVALID_PARAMETER;
326
327 if (!efi_var_mem_find(vendor, variable_name, &var) && *variable_name)
328 return EFI_INVALID_PARAMETER;
329
330 if (!var)
331 return EFI_NOT_FOUND;
332
333 for (pdata = var->name; *pdata; ++pdata)
334 ;
335 ++pdata;
336
337 old_size = *variable_name_size;
338 *variable_name_size = (uintptr_t)pdata - (uintptr_t)var->name;
339
340 if (old_size < *variable_name_size)
341 return EFI_BUFFER_TOO_SMALL;
342
343 efi_memcpy_runtime(variable_name, var->name, *variable_name_size);
344 efi_memcpy_runtime(vendor, &var->guid, sizeof(efi_guid_t));
345
346 return EFI_SUCCESS;
347 }
348
efi_var_buf_update(struct efi_var_file * var_buf)349 void efi_var_buf_update(struct efi_var_file *var_buf)
350 {
351 memcpy(efi_var_buf, var_buf, EFI_VAR_BUF_SIZE);
352 }
353