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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (C) 2020 Arm Limited
4 *
5 * Based on arch/arm64/kernel/machine_kexec_file.c:
6 * Copyright (C) 2018 Linaro Limited
7 *
8 * And arch/powerpc/kexec/file_load.c:
9 * Copyright (C) 2016 IBM Corporation
10 */
11
12#include <linux/ima.h>
13#include <linux/kernel.h>
14#include <linux/kexec.h>
15#include <linux/memblock.h>
16#include <linux/libfdt.h>
17#include <linux/of.h>
18#include <linux/of_fdt.h>
19#include <linux/random.h>
20#include <linux/slab.h>
21#include <linux/types.h>
22
23#define RNG_SEED_SIZE 128
24
25/*
26 * Additional space needed for the FDT buffer so that we can add initrd,
27 * bootargs, kaslr-seed, rng-seed, useable-memory-range and elfcorehdr.
28 */
29#define FDT_EXTRA_SPACE 0x1000
30
31/**
32 * fdt_find_and_del_mem_rsv - delete memory reservation with given address and size
33 *
34 * @fdt: Flattened device tree for the current kernel.
35 * @start: Starting address of the reserved memory.
36 * @size: Size of the reserved memory.
37 *
38 * Return: 0 on success, or negative errno on error.
39 */
40static int fdt_find_and_del_mem_rsv(void *fdt, unsigned long start, unsigned long size)
41{
42 int i, ret, num_rsvs = fdt_num_mem_rsv(fdt);
43
44 for (i = 0; i < num_rsvs; i++) {
45 u64 rsv_start, rsv_size;
46
47 ret = fdt_get_mem_rsv(fdt, i, &rsv_start, &rsv_size);
48 if (ret) {
49 pr_err("Malformed device tree.\n");
50 return -EINVAL;
51 }
52
53 if (rsv_start == start && rsv_size == size) {
54 ret = fdt_del_mem_rsv(fdt, i);
55 if (ret) {
56 pr_err("Error deleting device tree reservation.\n");
57 return -EINVAL;
58 }
59
60 return 0;
61 }
62 }
63
64 return -ENOENT;
65}
66
67/**
68 * get_addr_size_cells - Get address and size of root node
69 *
70 * @addr_cells: Return address of the root node
71 * @size_cells: Return size of the root node
72 *
73 * Return: 0 on success, or negative errno on error.
74 */
75static int get_addr_size_cells(int *addr_cells, int *size_cells)
76{
77 struct device_node *root;
78
79 root = of_find_node_by_path("/");
80 if (!root)
81 return -EINVAL;
82
83 *addr_cells = of_n_addr_cells(root);
84 *size_cells = of_n_size_cells(root);
85
86 of_node_put(root);
87
88 return 0;
89}
90
91/**
92 * do_get_kexec_buffer - Get address and size of device tree property
93 *
94 * @prop: Device tree property
95 * @len: Size of @prop
96 * @addr: Return address of the node
97 * @size: Return size of the node
98 *
99 * Return: 0 on success, or negative errno on error.
100 */
101static int do_get_kexec_buffer(const void *prop, int len, unsigned long *addr,
102 size_t *size)
103{
104 int ret, addr_cells, size_cells;
105
106 ret = get_addr_size_cells(&addr_cells, &size_cells);
107 if (ret)
108 return ret;
109
110 if (len < 4 * (addr_cells + size_cells))
111 return -ENOENT;
112
113 *addr = of_read_number(prop, addr_cells);
114 *size = of_read_number(prop + 4 * addr_cells, size_cells);
115
116 return 0;
117}
118
119#ifdef CONFIG_HAVE_IMA_KEXEC
120/**
121 * ima_get_kexec_buffer - get IMA buffer from the previous kernel
122 * @addr: On successful return, set to point to the buffer contents.
123 * @size: On successful return, set to the buffer size.
124 *
125 * Return: 0 on success, negative errno on error.
126 */
127int __init ima_get_kexec_buffer(void **addr, size_t *size)
128{
129 int ret, len;
130 unsigned long tmp_addr;
131 size_t tmp_size;
132 const void *prop;
133
134 prop = of_get_property(of_chosen, "linux,ima-kexec-buffer", &len);
135 if (!prop)
136 return -ENOENT;
137
138 ret = do_get_kexec_buffer(prop, len, &tmp_addr, &tmp_size);
139 if (ret)
140 return ret;
141
142 /* Do some sanity on the returned size for the ima-kexec buffer */
143 if (!tmp_size)
144 return -ENOENT;
145
146 ret = ima_validate_range(tmp_addr, tmp_size);
147 if (ret)
148 return ret;
149
150 *addr = __va(tmp_addr);
151 *size = tmp_size;
152
153 return 0;
154}
155
156/**
157 * ima_free_kexec_buffer - free memory used by the IMA buffer
158 */
159int __init ima_free_kexec_buffer(void)
160{
161 int ret;
162 unsigned long addr;
163 size_t size;
164 struct property *prop;
165
166 prop = of_find_property(of_chosen, "linux,ima-kexec-buffer", NULL);
167 if (!prop)
168 return -ENOENT;
169
170 ret = do_get_kexec_buffer(prop->value, prop->length, &addr, &size);
171 if (ret)
172 return ret;
173
174 ret = of_remove_property(of_chosen, prop);
175 if (ret)
176 return ret;
177
178 memblock_phys_free(addr, size);
179 return 0;
180}
181#endif
182
183/**
184 * remove_ima_buffer - remove the IMA buffer property and reservation from @fdt
185 *
186 * @fdt: Flattened Device Tree to update
187 * @chosen_node: Offset to the chosen node in the device tree
188 *
189 * The IMA measurement buffer is of no use to a subsequent kernel, so we always
190 * remove it from the device tree.
191 */
192static void remove_ima_buffer(void *fdt, int chosen_node)
193{
194 int ret, len;
195 unsigned long addr;
196 size_t size;
197 const void *prop;
198
199 if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC))
200 return;
201
202 prop = fdt_getprop(fdt, chosen_node, "linux,ima-kexec-buffer", &len);
203 if (!prop)
204 return;
205
206 ret = do_get_kexec_buffer(prop, len, &addr, &size);
207 fdt_delprop(fdt, chosen_node, "linux,ima-kexec-buffer");
208 if (ret)
209 return;
210
211 ret = fdt_find_and_del_mem_rsv(fdt, addr, size);
212 if (!ret)
213 pr_debug("Removed old IMA buffer reservation.\n");
214}
215
216#ifdef CONFIG_IMA_KEXEC
217/**
218 * setup_ima_buffer - add IMA buffer information to the fdt
219 * @image: kexec image being loaded.
220 * @fdt: Flattened device tree for the next kernel.
221 * @chosen_node: Offset to the chosen node.
222 *
223 * Return: 0 on success, or negative errno on error.
224 */
225static int setup_ima_buffer(const struct kimage *image, void *fdt,
226 int chosen_node)
227{
228 int ret;
229
230 if (!image->ima_buffer_size)
231 return 0;
232
233 ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
234 "linux,ima-kexec-buffer",
235 image->ima_buffer_addr,
236 image->ima_buffer_size);
237 if (ret < 0)
238 return -EINVAL;
239
240 ret = fdt_add_mem_rsv(fdt, image->ima_buffer_addr,
241 image->ima_buffer_size);
242 if (ret)
243 return -EINVAL;
244
245 pr_debug("IMA buffer at 0x%llx, size = 0x%zx\n",
246 image->ima_buffer_addr, image->ima_buffer_size);
247
248 return 0;
249}
250#else /* CONFIG_IMA_KEXEC */
251static inline int setup_ima_buffer(const struct kimage *image, void *fdt,
252 int chosen_node)
253{
254 return 0;
255}
256#endif /* CONFIG_IMA_KEXEC */
257
258static int kho_add_chosen(const struct kimage *image, void *fdt, int chosen_node)
259{
260 int ret = 0;
261#ifdef CONFIG_KEXEC_HANDOVER
262 phys_addr_t fdt_mem = 0;
263 phys_addr_t fdt_len = 0;
264 phys_addr_t scratch_mem = 0;
265 phys_addr_t scratch_len = 0;
266
267 ret = fdt_delprop(fdt, chosen_node, "linux,kho-fdt");
268 if (ret && ret != -FDT_ERR_NOTFOUND)
269 return ret;
270 ret = fdt_delprop(fdt, chosen_node, "linux,kho-scratch");
271 if (ret && ret != -FDT_ERR_NOTFOUND)
272 return ret;
273
274 if (!image->kho.fdt || !image->kho.scratch)
275 return 0;
276
277 fdt_mem = image->kho.fdt;
278 fdt_len = PAGE_SIZE;
279 scratch_mem = image->kho.scratch->mem;
280 scratch_len = image->kho.scratch->bufsz;
281
282 pr_debug("Adding kho metadata to DT");
283
284 ret = fdt_appendprop_addrrange(fdt, 0, chosen_node, "linux,kho-fdt",
285 fdt_mem, fdt_len);
286 if (ret)
287 return ret;
288 ret = fdt_appendprop_addrrange(fdt, 0, chosen_node, "linux,kho-scratch",
289 scratch_mem, scratch_len);
290
291#endif /* CONFIG_KEXEC_HANDOVER */
292 return ret;
293}
294
295/*
296 * of_kexec_alloc_and_setup_fdt - Alloc and setup a new Flattened Device Tree
297 *
298 * @image: kexec image being loaded.
299 * @initrd_load_addr: Address where the next initrd will be loaded.
300 * @initrd_len: Size of the next initrd, or 0 if there will be none.
301 * @cmdline: Command line for the next kernel, or NULL if there will
302 * be none.
303 * @extra_fdt_size: Additional size for the new FDT buffer.
304 *
305 * Return: fdt on success, or NULL errno on error.
306 */
307void *of_kexec_alloc_and_setup_fdt(const struct kimage *image,
308 unsigned long initrd_load_addr,
309 unsigned long initrd_len,
310 const char *cmdline, size_t extra_fdt_size)
311{
312 void *fdt;
313 int ret, chosen_node, len;
314 const void *prop;
315 size_t fdt_size;
316
317 fdt_size = fdt_totalsize(initial_boot_params) +
318 (cmdline ? strlen(cmdline) : 0) +
319 FDT_EXTRA_SPACE +
320 extra_fdt_size;
321 fdt = kvmalloc(fdt_size, GFP_KERNEL);
322 if (!fdt)
323 return NULL;
324
325 ret = fdt_open_into(initial_boot_params, fdt, fdt_size);
326 if (ret < 0) {
327 pr_err("Error %d setting up the new device tree.\n", ret);
328 goto out;
329 }
330
331 /* Remove memory reservation for the current device tree. */
332 ret = fdt_find_and_del_mem_rsv(fdt, initial_boot_params_pa,
333 fdt_totalsize(initial_boot_params));
334 if (ret == -EINVAL) {
335 pr_err("Error removing memory reservation.\n");
336 goto out;
337 }
338
339 chosen_node = fdt_path_offset(fdt, "/chosen");
340 if (chosen_node == -FDT_ERR_NOTFOUND)
341 chosen_node = fdt_add_subnode(fdt, fdt_path_offset(fdt, "/"),
342 "chosen");
343 if (chosen_node < 0) {
344 ret = chosen_node;
345 goto out;
346 }
347
348 ret = fdt_delprop(fdt, chosen_node, "linux,elfcorehdr");
349 if (ret && ret != -FDT_ERR_NOTFOUND)
350 goto out;
351 ret = fdt_delprop(fdt, chosen_node, "linux,usable-memory-range");
352 if (ret && ret != -FDT_ERR_NOTFOUND)
353 goto out;
354
355 /* Did we boot using an initrd? */
356 prop = fdt_getprop(fdt, chosen_node, "linux,initrd-start", &len);
357 if (prop) {
358 u64 tmp_start, tmp_end, tmp_size;
359
360 tmp_start = of_read_number(prop, len / 4);
361
362 prop = fdt_getprop(fdt, chosen_node, "linux,initrd-end", &len);
363 if (!prop) {
364 ret = -EINVAL;
365 goto out;
366 }
367
368 tmp_end = of_read_number(prop, len / 4);
369
370 /*
371 * kexec reserves exact initrd size, while firmware may
372 * reserve a multiple of PAGE_SIZE, so check for both.
373 */
374 tmp_size = tmp_end - tmp_start;
375 ret = fdt_find_and_del_mem_rsv(fdt, tmp_start, tmp_size);
376 if (ret == -ENOENT)
377 ret = fdt_find_and_del_mem_rsv(fdt, tmp_start,
378 round_up(tmp_size, PAGE_SIZE));
379 if (ret == -EINVAL)
380 goto out;
381 }
382
383 /* add initrd-* */
384 if (initrd_load_addr) {
385 ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-start",
386 initrd_load_addr);
387 if (ret)
388 goto out;
389
390 ret = fdt_setprop_u64(fdt, chosen_node, "linux,initrd-end",
391 initrd_load_addr + initrd_len);
392 if (ret)
393 goto out;
394
395 ret = fdt_add_mem_rsv(fdt, initrd_load_addr, initrd_len);
396 if (ret)
397 goto out;
398
399 } else {
400 ret = fdt_delprop(fdt, chosen_node, "linux,initrd-start");
401 if (ret && (ret != -FDT_ERR_NOTFOUND))
402 goto out;
403
404 ret = fdt_delprop(fdt, chosen_node, "linux,initrd-end");
405 if (ret && (ret != -FDT_ERR_NOTFOUND))
406 goto out;
407 }
408
409 if (image->type == KEXEC_TYPE_CRASH) {
410 /* add linux,elfcorehdr */
411 ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
412 "linux,elfcorehdr", image->elf_load_addr,
413 image->elf_headers_sz);
414 if (ret)
415 goto out;
416
417 /*
418 * Avoid elfcorehdr from being stomped on in kdump kernel by
419 * setting up memory reserve map.
420 */
421 ret = fdt_add_mem_rsv(fdt, image->elf_load_addr,
422 image->elf_headers_sz);
423 if (ret)
424 goto out;
425
426 if (image->dm_crypt_keys_addr != 0) {
427 ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
428 "linux,dmcryptkeys",
429 image->dm_crypt_keys_addr,
430 image->dm_crypt_keys_sz);
431
432 if (ret)
433 goto out;
434
435 /*
436 * Avoid dmcryptkeys from being stomped on in kdump kernel by
437 * setting up memory reserve map.
438 */
439 ret = fdt_add_mem_rsv(fdt, image->dm_crypt_keys_addr,
440 image->dm_crypt_keys_sz);
441 if (ret)
442 goto out;
443 }
444
445#ifdef CONFIG_CRASH_DUMP
446 /* add linux,usable-memory-range */
447 ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
448 "linux,usable-memory-range", crashk_res.start,
449 crashk_res.end - crashk_res.start + 1);
450 if (ret)
451 goto out;
452
453 if (crashk_low_res.end) {
454 ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
455 "linux,usable-memory-range",
456 crashk_low_res.start,
457 crashk_low_res.end - crashk_low_res.start + 1);
458 if (ret)
459 goto out;
460 }
461
462 for (int i = 0; i < crashk_cma_cnt; i++) {
463 ret = fdt_appendprop_addrrange(fdt, 0, chosen_node,
464 "linux,usable-memory-range",
465 crashk_cma_ranges[i].start,
466 crashk_cma_ranges[i].end - crashk_cma_ranges[i].start + 1);
467 if (ret)
468 goto out;
469 }
470#endif
471 }
472
473 /* Add kho metadata if this is a KHO image */
474 ret = kho_add_chosen(image, fdt, chosen_node);
475 if (ret)
476 goto out;
477
478 /* add bootargs */
479 if (cmdline) {
480 ret = fdt_setprop_string(fdt, chosen_node, "bootargs", cmdline);
481 if (ret)
482 goto out;
483 } else {
484 ret = fdt_delprop(fdt, chosen_node, "bootargs");
485 if (ret && (ret != -FDT_ERR_NOTFOUND))
486 goto out;
487 }
488
489 /* add kaslr-seed */
490 ret = fdt_delprop(fdt, chosen_node, "kaslr-seed");
491 if (ret == -FDT_ERR_NOTFOUND)
492 ret = 0;
493 else if (ret)
494 goto out;
495
496 if (rng_is_initialized()) {
497 u64 seed = get_random_u64();
498
499 ret = fdt_setprop_u64(fdt, chosen_node, "kaslr-seed", seed);
500 if (ret)
501 goto out;
502 } else {
503 pr_notice("RNG is not initialised: omitting \"%s\" property\n",
504 "kaslr-seed");
505 }
506
507 /* add rng-seed */
508 if (rng_is_initialized()) {
509 void *rng_seed;
510
511 ret = fdt_setprop_placeholder(fdt, chosen_node, "rng-seed",
512 RNG_SEED_SIZE, &rng_seed);
513 if (ret)
514 goto out;
515 get_random_bytes(rng_seed, RNG_SEED_SIZE);
516 } else {
517 pr_notice("RNG is not initialised: omitting \"%s\" property\n",
518 "rng-seed");
519 }
520
521 ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
522 if (ret)
523 goto out;
524
525 remove_ima_buffer(fdt, chosen_node);
526 ret = setup_ima_buffer(image, fdt, fdt_path_offset(fdt, "/chosen"));
527
528out:
529 if (ret) {
530 kvfree(fdt);
531 fdt = NULL;
532 }
533
534 return fdt;
535}