1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * POWER LPAR Platform KeyStore(PLPKS)
4 * Copyright (C) 2022 IBM Corporation
5 * Author: Nayna Jain <nayna@linux.ibm.com>
6 *
7 * Provides access to variables stored in Power LPAR Platform KeyStore(PLPKS).
8 */
9
10 #define pr_fmt(fmt) "plpks: " fmt
11
12 #include <linux/delay.h>
13 #include <linux/errno.h>
14 #include <linux/io.h>
15 #include <linux/printk.h>
16 #include <linux/slab.h>
17 #include <linux/string.h>
18 #include <linux/types.h>
19 #include <linux/of_fdt.h>
20 #include <linux/libfdt.h>
21 #include <linux/memblock.h>
22 #include <asm/hvcall.h>
23 #include <asm/machdep.h>
24 #include <asm/plpks.h>
25 #include <asm/firmware.h>
26
27 static u8 *ospassword;
28 static u16 ospasswordlength;
29
30 // Retrieved with H_PKS_GET_CONFIG
31 static u8 version;
32 static u16 objoverhead;
33 static u16 maxpwsize;
34 static u16 maxobjsize;
35 static s16 maxobjlabelsize;
36 static u32 totalsize;
37 static u32 usedspace;
38 static u32 supportedpolicies;
39 static u32 maxlargeobjectsize;
40 static u64 signedupdatealgorithms;
41
42 struct plpks_auth {
43 u8 version;
44 u8 consumer;
45 __be64 rsvd0;
46 __be32 rsvd1;
47 __be16 passwordlength;
48 u8 password[];
49 } __packed __aligned(16);
50
51 struct label_attr {
52 u8 prefix[8];
53 u8 version;
54 u8 os;
55 u8 length;
56 u8 reserved[5];
57 };
58
59 struct label {
60 struct label_attr attr;
61 u8 name[PLPKS_MAX_NAME_SIZE];
62 size_t size;
63 };
64
65 static int pseries_status_to_err(int rc)
66 {
67 int err;
68
69 switch (rc) {
70 case H_SUCCESS:
71 err = 0;
72 break;
73 case H_FUNCTION:
74 err = -ENXIO;
75 break;
76 case H_PARAMETER:
77 case H_P2:
78 case H_P3:
79 case H_P4:
80 case H_P5:
81 case H_P6:
82 err = -EINVAL;
83 break;
84 case H_NOT_FOUND:
85 err = -ENOENT;
86 break;
87 case H_BUSY:
88 case H_LONG_BUSY_ORDER_1_MSEC:
89 case H_LONG_BUSY_ORDER_10_MSEC:
90 case H_LONG_BUSY_ORDER_100_MSEC:
91 case H_LONG_BUSY_ORDER_1_SEC:
92 case H_LONG_BUSY_ORDER_10_SEC:
93 case H_LONG_BUSY_ORDER_100_SEC:
94 err = -EBUSY;
95 break;
96 case H_AUTHORITY:
97 err = -EPERM;
98 break;
99 case H_NO_MEM:
100 err = -ENOMEM;
101 break;
102 case H_RESOURCE:
103 err = -EEXIST;
104 break;
105 case H_TOO_BIG:
106 err = -EFBIG;
107 break;
108 case H_STATE:
109 err = -EIO;
110 break;
111 case H_R_STATE:
112 err = -EIO;
113 break;
114 case H_IN_USE:
115 err = -EEXIST;
116 break;
117 case H_ABORTED:
118 err = -EIO;
119 break;
120 default:
121 err = -EINVAL;
122 }
123
124 pr_debug("Converted hypervisor code %d to Linux %d\n", rc, err);
125
126 return err;
127 }
128
129 static int plpks_gen_password(void)
130 {
131 unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
132 u8 *password, consumer = PLPKS_OS_OWNER;
133 int rc;
134
135 // If we booted from kexec, we could be reusing an existing password already
136 if (ospassword) {
137 pr_debug("Password of length %u already in use\n", ospasswordlength);
138 return 0;
139 }
140
141 // The password must not cross a page boundary, so we align to the next power of 2
142 password = kzalloc(roundup_pow_of_two(maxpwsize), GFP_KERNEL);
143 if (!password)
144 return -ENOMEM;
145
146 rc = plpar_hcall(H_PKS_GEN_PASSWORD, retbuf, consumer, 0,
147 virt_to_phys(password), maxpwsize);
148
149 if (!rc) {
150 ospasswordlength = maxpwsize;
151 ospassword = kzalloc(maxpwsize, GFP_KERNEL);
152 if (!ospassword) {
153 kfree_sensitive(password);
154 return -ENOMEM;
155 }
156 memcpy(ospassword, password, ospasswordlength);
157 } else {
158 if (rc == H_IN_USE) {
159 pr_warn("Password already set - authenticated operations will fail\n");
160 rc = 0;
161 } else {
162 goto out;
163 }
164 }
165 out:
166 kfree_sensitive(password);
167
168 return pseries_status_to_err(rc);
169 }
170
171 static struct plpks_auth *construct_auth(u8 consumer)
172 {
173 struct plpks_auth *auth;
174
175 if (consumer > PLPKS_OS_OWNER)
176 return ERR_PTR(-EINVAL);
177
178 // The auth structure must not cross a page boundary and must be
179 // 16 byte aligned. We align to the next largest power of 2
180 auth = kzalloc(roundup_pow_of_two(struct_size(auth, password, maxpwsize)), GFP_KERNEL);
181 if (!auth)
182 return ERR_PTR(-ENOMEM);
183
184 auth->version = 1;
185 auth->consumer = consumer;
186
187 if (consumer == PLPKS_FW_OWNER || consumer == PLPKS_BOOTLOADER_OWNER)
188 return auth;
189
190 memcpy(auth->password, ospassword, ospasswordlength);
191
192 auth->passwordlength = cpu_to_be16(ospasswordlength);
193
194 return auth;
195 }
196
197 /*
198 * Label is combination of label attributes + name.
199 * Label attributes are used internally by kernel and not exposed to the user.
200 */
201 static struct label *construct_label(char *component, u8 varos, u8 *name,
202 u16 namelen)
203 {
204 struct label *label;
205 size_t slen = 0;
206
207 if (!name || namelen > PLPKS_MAX_NAME_SIZE)
208 return ERR_PTR(-EINVAL);
209
210 // Support NULL component for signed updates
211 if (component) {
212 slen = strlen(component);
213 if (slen > sizeof(label->attr.prefix))
214 return ERR_PTR(-EINVAL);
215 }
216
217 // The label structure must not cross a page boundary, so we align to the next power of 2
218 label = kzalloc(roundup_pow_of_two(sizeof(*label)), GFP_KERNEL);
219 if (!label)
220 return ERR_PTR(-ENOMEM);
221
222 if (component)
223 memcpy(&label->attr.prefix, component, slen);
224
225 label->attr.version = PLPKS_LABEL_VERSION;
226 label->attr.os = varos;
227 label->attr.length = PLPKS_MAX_LABEL_ATTR_SIZE;
228 memcpy(&label->name, name, namelen);
229
230 label->size = sizeof(struct label_attr) + namelen;
231
232 return label;
233 }
234
235 static int _plpks_get_config(void)
236 {
237 unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
238 struct config {
239 u8 version;
240 u8 flags;
241 __be16 rsvd0;
242 __be16 objoverhead;
243 __be16 maxpwsize;
244 __be16 maxobjlabelsize;
245 __be16 maxobjsize;
246 __be32 totalsize;
247 __be32 usedspace;
248 __be32 supportedpolicies;
249 __be32 maxlargeobjectsize;
250 __be64 signedupdatealgorithms;
251 u8 rsvd1[476];
252 } __packed * config;
253 size_t size;
254 int rc = 0;
255
256 size = sizeof(*config);
257
258 // Config struct must not cross a page boundary. So long as the struct
259 // size is a power of 2, this should be fine as alignment is guaranteed
260 config = kzalloc(size, GFP_KERNEL);
261 if (!config) {
262 rc = -ENOMEM;
263 goto err;
264 }
265
266 rc = plpar_hcall(H_PKS_GET_CONFIG, retbuf, virt_to_phys(config), size);
267
268 if (rc != H_SUCCESS) {
269 rc = pseries_status_to_err(rc);
270 goto err;
271 }
272
273 version = config->version;
274 objoverhead = be16_to_cpu(config->objoverhead);
275 maxpwsize = be16_to_cpu(config->maxpwsize);
276 maxobjsize = be16_to_cpu(config->maxobjsize);
277 maxobjlabelsize = be16_to_cpu(config->maxobjlabelsize);
278 totalsize = be32_to_cpu(config->totalsize);
279 usedspace = be32_to_cpu(config->usedspace);
280 supportedpolicies = be32_to_cpu(config->supportedpolicies);
281 maxlargeobjectsize = be32_to_cpu(config->maxlargeobjectsize);
282 signedupdatealgorithms = be64_to_cpu(config->signedupdatealgorithms);
283
284 // Validate that the numbers we get back match the requirements of the spec
285 if (maxpwsize < 32) {
286 pr_err("Invalid Max Password Size received from hypervisor (%d < 32)\n", maxpwsize);
287 rc = -EIO;
288 goto err;
289 }
290
291 if (maxobjlabelsize < 255) {
292 pr_err("Invalid Max Object Label Size received from hypervisor (%d < 255)\n",
293 maxobjlabelsize);
294 rc = -EIO;
295 goto err;
296 }
297
298 if (totalsize < 4096) {
299 pr_err("Invalid Total Size received from hypervisor (%d < 4096)\n", totalsize);
300 rc = -EIO;
301 goto err;
302 }
303
304 if (version >= 3 && maxlargeobjectsize >= 65536 && maxobjsize != 0xFFFF) {
305 pr_err("Invalid Max Object Size (0x%x != 0xFFFF)\n", maxobjsize);
306 rc = -EIO;
307 goto err;
308 }
309
310 err:
311 kfree(config);
312 return rc;
313 }
314
315 u8 plpks_get_version(void)
316 {
317 return version;
318 }
319
320 u16 plpks_get_objoverhead(void)
321 {
322 return objoverhead;
323 }
324
325 u16 plpks_get_maxpwsize(void)
326 {
327 return maxpwsize;
328 }
329
330 u16 plpks_get_maxobjectsize(void)
331 {
332 return maxobjsize;
333 }
334
335 u16 plpks_get_maxobjectlabelsize(void)
336 {
337 return maxobjlabelsize;
338 }
339
340 u32 plpks_get_totalsize(void)
341 {
342 return totalsize;
343 }
344
345 u32 plpks_get_usedspace(void)
346 {
347 // Unlike other config values, usedspace regularly changes as objects
348 // are updated, so we need to refresh.
349 int rc = _plpks_get_config();
350 if (rc) {
351 pr_err("Couldn't get config, rc: %d\n", rc);
352 return 0;
353 }
354 return usedspace;
355 }
356
357 u32 plpks_get_supportedpolicies(void)
358 {
359 return supportedpolicies;
360 }
361
362 u32 plpks_get_maxlargeobjectsize(void)
363 {
364 return maxlargeobjectsize;
365 }
366
367 u64 plpks_get_signedupdatealgorithms(void)
368 {
369 return signedupdatealgorithms;
370 }
371
372 u16 plpks_get_passwordlen(void)
373 {
374 return ospasswordlength;
375 }
376
377 bool plpks_is_available(void)
378 {
379 int rc;
380
381 if (!firmware_has_feature(FW_FEATURE_PLPKS))
382 return false;
383
384 rc = _plpks_get_config();
385 if (rc)
386 return false;
387
388 return true;
389 }
390
391 static int plpks_confirm_object_flushed(struct label *label,
392 struct plpks_auth *auth)
393 {
394 unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
395 bool timed_out = true;
396 u64 timeout = 0;
397 u8 status;
398 int rc;
399
400 do {
401 rc = plpar_hcall(H_PKS_CONFIRM_OBJECT_FLUSHED, retbuf,
402 virt_to_phys(auth), virt_to_phys(label),
403 label->size);
404
405 status = retbuf[0];
406 if (rc) {
407 timed_out = false;
408 if (rc == H_NOT_FOUND && status == 1)
409 rc = 0;
410 break;
411 }
412
413 if (!rc && status == 1) {
414 timed_out = false;
415 break;
416 }
417
418 fsleep(PLPKS_FLUSH_SLEEP);
419 timeout = timeout + PLPKS_FLUSH_SLEEP;
420 } while (timeout < PLPKS_MAX_TIMEOUT);
421
422 if (timed_out)
423 return -ETIMEDOUT;
424
425 return pseries_status_to_err(rc);
426 }
427
428 int plpks_signed_update_var(struct plpks_var *var, u64 flags)
429 {
430 unsigned long retbuf[PLPAR_HCALL9_BUFSIZE] = {0};
431 int rc;
432 struct label *label;
433 struct plpks_auth *auth;
434 u64 continuetoken = 0;
435 u64 timeout = 0;
436
437 if (!var->data || var->datalen <= 0 || var->namelen > PLPKS_MAX_NAME_SIZE)
438 return -EINVAL;
439
440 if (!(var->policy & PLPKS_SIGNEDUPDATE))
441 return -EINVAL;
442
443 // Signed updates need the component to be NULL.
444 if (var->component)
445 return -EINVAL;
446
447 auth = construct_auth(PLPKS_OS_OWNER);
448 if (IS_ERR(auth))
449 return PTR_ERR(auth);
450
451 label = construct_label(var->component, var->os, var->name, var->namelen);
452 if (IS_ERR(label)) {
453 rc = PTR_ERR(label);
454 goto out;
455 }
456
457 do {
458 rc = plpar_hcall9(H_PKS_SIGNED_UPDATE, retbuf,
459 virt_to_phys(auth), virt_to_phys(label),
460 label->size, var->policy, flags,
461 virt_to_phys(var->data), var->datalen,
462 continuetoken);
463
464 continuetoken = retbuf[0];
465 if (pseries_status_to_err(rc) == -EBUSY) {
466 int delay_us = get_longbusy_msecs(rc) * 1000;
467
468 fsleep(delay_us);
469 timeout += delay_us;
470 }
471 rc = pseries_status_to_err(rc);
472 } while (rc == -EBUSY && timeout < PLPKS_MAX_TIMEOUT);
473
474 if (!rc)
475 rc = plpks_confirm_object_flushed(label, auth);
476
477 kfree(label);
478 out:
479 kfree(auth);
480
481 return rc;
482 }
483
484 int plpks_write_var(struct plpks_var var)
485 {
486 unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
487 struct plpks_auth *auth;
488 struct label *label;
489 int rc;
490
491 if (!var.component || !var.data || var.datalen <= 0 ||
492 var.namelen > PLPKS_MAX_NAME_SIZE || var.datalen > PLPKS_MAX_DATA_SIZE)
493 return -EINVAL;
494
495 if (var.policy & PLPKS_SIGNEDUPDATE)
496 return -EINVAL;
497
498 auth = construct_auth(PLPKS_OS_OWNER);
499 if (IS_ERR(auth))
500 return PTR_ERR(auth);
501
502 label = construct_label(var.component, var.os, var.name, var.namelen);
503 if (IS_ERR(label)) {
504 rc = PTR_ERR(label);
505 goto out;
506 }
507
508 rc = plpar_hcall(H_PKS_WRITE_OBJECT, retbuf, virt_to_phys(auth),
509 virt_to_phys(label), label->size, var.policy,
510 virt_to_phys(var.data), var.datalen);
511
512 if (!rc)
513 rc = plpks_confirm_object_flushed(label, auth);
514
515 rc = pseries_status_to_err(rc);
516 kfree(label);
517 out:
518 kfree(auth);
519
520 return rc;
521 }
522
523 int plpks_remove_var(char *component, u8 varos, struct plpks_var_name vname)
524 {
525 unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
526 struct plpks_auth *auth;
527 struct label *label;
528 int rc;
529
530 if (vname.namelen > PLPKS_MAX_NAME_SIZE)
531 return -EINVAL;
532
533 auth = construct_auth(PLPKS_OS_OWNER);
534 if (IS_ERR(auth))
535 return PTR_ERR(auth);
536
537 label = construct_label(component, varos, vname.name, vname.namelen);
538 if (IS_ERR(label)) {
539 rc = PTR_ERR(label);
540 goto out;
541 }
542
543 rc = plpar_hcall(H_PKS_REMOVE_OBJECT, retbuf, virt_to_phys(auth),
544 virt_to_phys(label), label->size);
545
546 if (!rc)
547 rc = plpks_confirm_object_flushed(label, auth);
548
549 rc = pseries_status_to_err(rc);
550 kfree(label);
551 out:
552 kfree(auth);
553
554 return rc;
555 }
556
557 static int plpks_read_var(u8 consumer, struct plpks_var *var)
558 {
559 unsigned long retbuf[PLPAR_HCALL_BUFSIZE] = { 0 };
560 struct plpks_auth *auth;
561 struct label *label = NULL;
562 u8 *output;
563 int rc;
564
565 if (var->namelen > PLPKS_MAX_NAME_SIZE)
566 return -EINVAL;
567
568 auth = construct_auth(consumer);
569 if (IS_ERR(auth))
570 return PTR_ERR(auth);
571
572 if (consumer == PLPKS_OS_OWNER) {
573 label = construct_label(var->component, var->os, var->name,
574 var->namelen);
575 if (IS_ERR(label)) {
576 rc = PTR_ERR(label);
577 goto out_free_auth;
578 }
579 }
580
581 output = kzalloc(maxobjsize, GFP_KERNEL);
582 if (!output) {
583 rc = -ENOMEM;
584 goto out_free_label;
585 }
586
587 if (consumer == PLPKS_OS_OWNER)
588 rc = plpar_hcall(H_PKS_READ_OBJECT, retbuf, virt_to_phys(auth),
589 virt_to_phys(label), label->size, virt_to_phys(output),
590 maxobjsize);
591 else
592 rc = plpar_hcall(H_PKS_READ_OBJECT, retbuf, virt_to_phys(auth),
593 virt_to_phys(var->name), var->namelen, virt_to_phys(output),
594 maxobjsize);
595
596
597 if (rc != H_SUCCESS) {
598 rc = pseries_status_to_err(rc);
599 goto out_free_output;
600 }
601
602 if (!var->data || var->datalen > retbuf[0])
603 var->datalen = retbuf[0];
604
605 var->policy = retbuf[1];
606
607 if (var->data)
608 memcpy(var->data, output, var->datalen);
609
610 rc = 0;
611
612 out_free_output:
613 kfree(output);
614 out_free_label:
615 kfree(label);
616 out_free_auth:
617 kfree(auth);
618
619 return rc;
620 }
621
622 int plpks_read_os_var(struct plpks_var *var)
623 {
624 return plpks_read_var(PLPKS_OS_OWNER, var);
625 }
626
627 int plpks_read_fw_var(struct plpks_var *var)
628 {
629 return plpks_read_var(PLPKS_FW_OWNER, var);
630 }
631
632 int plpks_read_bootloader_var(struct plpks_var *var)
633 {
634 return plpks_read_var(PLPKS_BOOTLOADER_OWNER, var);
635 }
636
637 int plpks_populate_fdt(void *fdt)
638 {
639 int chosen_offset = fdt_path_offset(fdt, "/chosen");
640
641 if (chosen_offset < 0) {
642 pr_err("Can't find chosen node: %s\n",
643 fdt_strerror(chosen_offset));
644 return chosen_offset;
645 }
646
647 return fdt_setprop(fdt, chosen_offset, "ibm,plpks-pw", ospassword, ospasswordlength);
648 }
649
650 // Once a password is registered with the hypervisor it cannot be cleared without
651 // rebooting the LPAR, so to keep using the PLPKS across kexec boots we need to
652 // recover the previous password from the FDT.
653 //
654 // There are a few challenges here. We don't want the password to be visible to
655 // users, so we need to clear it from the FDT. This has to be done in early boot.
656 // Clearing it from the FDT would make the FDT's checksum invalid, so we have to
657 // manually cause the checksum to be recalculated.
658 void __init plpks_early_init_devtree(void)
659 {
660 void *fdt = initial_boot_params;
661 int chosen_node = fdt_path_offset(fdt, "/chosen");
662 const u8 *password;
663 int len;
664
665 if (chosen_node < 0)
666 return;
667
668 password = fdt_getprop(fdt, chosen_node, "ibm,plpks-pw", &len);
669 if (len <= 0) {
670 pr_debug("Couldn't find ibm,plpks-pw node.\n");
671 return;
672 }
673
674 ospassword = memblock_alloc_raw(len, SMP_CACHE_BYTES);
675 if (!ospassword) {
676 pr_err("Error allocating memory for password.\n");
677 goto out;
678 }
679
680 memcpy(ospassword, password, len);
681 ospasswordlength = (u16)len;
682
683 out:
684 fdt_nop_property(fdt, chosen_node, "ibm,plpks-pw");
685 // Since we've cleared the password, we must update the FDT checksum
686 early_init_dt_verify(fdt);
687 }
688
689 static __init int pseries_plpks_init(void)
690 {
691 int rc;
692
693 if (!firmware_has_feature(FW_FEATURE_PLPKS))
694 return -ENODEV;
695
696 rc = _plpks_get_config();
697
698 if (rc) {
699 pr_err("POWER LPAR Platform KeyStore is not supported or enabled\n");
700 return rc;
701 }
702
703 rc = plpks_gen_password();
704 if (rc)
705 pr_err("Failed setting POWER LPAR Platform KeyStore Password\n");
706 else
707 pr_info("POWER LPAR Platform KeyStore initialized successfully\n");
708
709 return rc;
710 }
711 machine_arch_initcall(pseries, pseries_plpks_init);
712
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