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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * pkey base: debug feature, pkey handler registry
4 *
5 * Copyright IBM Corp. 2024
6 */
7
8#define pr_fmt(fmt) "pkey: " fmt
9
10#include <linux/cpufeature.h>
11#include <linux/export.h>
12#include <linux/init.h>
13#include <linux/list.h>
14#include <linux/module.h>
15#include <linux/rculist.h>
16
17#include "pkey_base.h"
18
19MODULE_LICENSE("GPL");
20MODULE_AUTHOR("IBM Corporation");
21MODULE_DESCRIPTION("s390 protected key base and api");
22
23/*
24 * pkey debug feature
25 */
26debug_info_t *pkey_dbf_info;
27EXPORT_SYMBOL(pkey_dbf_info);
28
29/*
30 * pkey handler registry
31 */
32
33static DEFINE_SPINLOCK(handler_list_write_lock);
34static LIST_HEAD(handler_list);
35
36int pkey_handler_register(struct pkey_handler *handler)
37{
38 const struct pkey_handler *h;
39
40 if (!handler ||
41 !handler->is_supported_key ||
42 !handler->is_supported_keytype)
43 return -EINVAL;
44
45 if (!try_module_get(handler->module))
46 return -ENXIO;
47
48 spin_lock(&handler_list_write_lock);
49
50 rcu_read_lock();
51 list_for_each_entry_rcu(h, &handler_list, list) {
52 if (h == handler) {
53 rcu_read_unlock();
54 spin_unlock(&handler_list_write_lock);
55 module_put(handler->module);
56 return -EEXIST;
57 }
58 }
59 rcu_read_unlock();
60
61 list_add_rcu(&handler->list, &handler_list);
62 spin_unlock(&handler_list_write_lock);
63 /*
64 * Fast path to push the info about the updated list to the other
65 * CPUs. If removed, the other CPUs may get the updated list when the
66 * RCU context is synched. As this code is in general not performance
67 * critical and the list update mostly only occurs at the early time in
68 * system startup the focus is on concurrency versus performance.
69 */
70 synchronize_rcu();
71
72 module_put(handler->module);
73
74 PKEY_DBF_INFO("%s pkey handler '%s' registered\n", __func__,
75 handler->name ?: "<no name>");
76
77 return 0;
78}
79EXPORT_SYMBOL(pkey_handler_register);
80
81int pkey_handler_unregister(struct pkey_handler *handler)
82{
83 spin_lock(&handler_list_write_lock);
84 list_del_rcu(&handler->list);
85 INIT_LIST_HEAD_RCU(&handler->list);
86 spin_unlock(&handler_list_write_lock);
87 synchronize_rcu();
88
89 PKEY_DBF_INFO("%s pkey handler '%s' unregistered\n", __func__,
90 handler->name ?: "<no name>");
91
92 return 0;
93}
94EXPORT_SYMBOL(pkey_handler_unregister);
95
96/*
97 * Handler invocation functions.
98 */
99
100const struct pkey_handler *pkey_handler_get_keybased(const u8 *key, u32 keylen)
101{
102 const struct pkey_handler *h;
103
104 rcu_read_lock();
105 list_for_each_entry_rcu(h, &handler_list, list) {
106 if (!try_module_get(h->module))
107 continue;
108 if (h->is_supported_key(key, keylen)) {
109 rcu_read_unlock();
110 return h;
111 }
112 module_put(h->module);
113 }
114 rcu_read_unlock();
115
116 return NULL;
117}
118EXPORT_SYMBOL(pkey_handler_get_keybased);
119
120const struct pkey_handler *pkey_handler_get_keytypebased(enum pkey_key_type kt)
121{
122 const struct pkey_handler *h;
123
124 rcu_read_lock();
125 list_for_each_entry_rcu(h, &handler_list, list) {
126 if (!try_module_get(h->module))
127 continue;
128 if (h->is_supported_keytype(kt)) {
129 rcu_read_unlock();
130 return h;
131 }
132 module_put(h->module);
133 }
134 rcu_read_unlock();
135
136 return NULL;
137}
138EXPORT_SYMBOL(pkey_handler_get_keytypebased);
139
140void pkey_handler_put(const struct pkey_handler *handler)
141{
142 const struct pkey_handler *h;
143
144 if (!handler)
145 return;
146
147 rcu_read_lock();
148 list_for_each_entry_rcu(h, &handler_list, list) {
149 if (h == handler) {
150 module_put(h->module);
151 break;
152 }
153 }
154 rcu_read_unlock();
155}
156EXPORT_SYMBOL(pkey_handler_put);
157
158int pkey_handler_key_to_protkey(const struct pkey_apqn *apqns, size_t nr_apqns,
159 const u8 *key, u32 keylen,
160 u8 *protkey, u32 *protkeylen, u32 *protkeytype,
161 u32 xflags)
162{
163 const struct pkey_handler *h;
164 int rc = -ENODEV;
165
166 h = pkey_handler_get_keybased(key, keylen);
167 if (h && h->key_to_protkey) {
168 rc = h->key_to_protkey(apqns, nr_apqns, key, keylen,
169 protkey, protkeylen,
170 protkeytype, xflags);
171 }
172 pkey_handler_put(h);
173
174 return rc;
175}
176EXPORT_SYMBOL(pkey_handler_key_to_protkey);
177
178/*
179 * This handler invocation is special as there may be more than
180 * one handler providing support for the very same key (type).
181 * And the handler may not respond true on is_supported_key(),
182 * so simple try and check return value here.
183 */
184int pkey_handler_slowpath_key_to_protkey(const struct pkey_apqn *apqns,
185 size_t nr_apqns,
186 const u8 *key, u32 keylen,
187 u8 *protkey, u32 *protkeylen,
188 u32 *protkeytype, u32 xflags)
189{
190 const struct pkey_handler *h, *htmp[10];
191 int i, n = 0, rc = -ENODEV;
192
193 rcu_read_lock();
194 list_for_each_entry_rcu(h, &handler_list, list) {
195 if (!try_module_get(h->module))
196 continue;
197 if (h->slowpath_key_to_protkey && n < ARRAY_SIZE(htmp))
198 htmp[n++] = h;
199 else
200 module_put(h->module);
201 }
202 rcu_read_unlock();
203
204 for (i = 0; i < n; i++) {
205 h = htmp[i];
206 if (rc)
207 rc = h->slowpath_key_to_protkey(apqns, nr_apqns,
208 key, keylen,
209 protkey, protkeylen,
210 protkeytype, xflags);
211 module_put(h->module);
212 }
213
214 return rc;
215}
216EXPORT_SYMBOL(pkey_handler_slowpath_key_to_protkey);
217
218int pkey_handler_gen_key(const struct pkey_apqn *apqns, size_t nr_apqns,
219 u32 keytype, u32 keysubtype,
220 u32 keybitsize, u32 flags,
221 u8 *keybuf, u32 *keybuflen, u32 *keyinfo, u32 xflags)
222{
223 const struct pkey_handler *h;
224 int rc = -ENODEV;
225
226 h = pkey_handler_get_keytypebased(keysubtype);
227 if (h && h->gen_key) {
228 rc = h->gen_key(apqns, nr_apqns, keytype, keysubtype,
229 keybitsize, flags,
230 keybuf, keybuflen, keyinfo, xflags);
231 }
232 pkey_handler_put(h);
233
234 return rc;
235}
236EXPORT_SYMBOL(pkey_handler_gen_key);
237
238int pkey_handler_clr_to_key(const struct pkey_apqn *apqns, size_t nr_apqns,
239 u32 keytype, u32 keysubtype,
240 u32 keybitsize, u32 flags,
241 const u8 *clrkey, u32 clrkeylen,
242 u8 *keybuf, u32 *keybuflen, u32 *keyinfo,
243 u32 xflags)
244{
245 const struct pkey_handler *h;
246 int rc = -ENODEV;
247
248 h = pkey_handler_get_keytypebased(keysubtype);
249 if (h && h->clr_to_key) {
250 rc = h->clr_to_key(apqns, nr_apqns, keytype, keysubtype,
251 keybitsize, flags, clrkey, clrkeylen,
252 keybuf, keybuflen, keyinfo, xflags);
253 }
254 pkey_handler_put(h);
255
256 return rc;
257}
258EXPORT_SYMBOL(pkey_handler_clr_to_key);
259
260int pkey_handler_verify_key(const u8 *key, u32 keylen,
261 u16 *card, u16 *dom,
262 u32 *keytype, u32 *keybitsize, u32 *flags,
263 u32 xflags)
264{
265 const struct pkey_handler *h;
266 int rc = -ENODEV;
267
268 h = pkey_handler_get_keybased(key, keylen);
269 if (h && h->verify_key) {
270 rc = h->verify_key(key, keylen, card, dom,
271 keytype, keybitsize, flags, xflags);
272 }
273 pkey_handler_put(h);
274
275 return rc;
276}
277EXPORT_SYMBOL(pkey_handler_verify_key);
278
279int pkey_handler_apqns_for_key(const u8 *key, u32 keylen, u32 flags,
280 struct pkey_apqn *apqns, size_t *nr_apqns,
281 u32 xflags)
282{
283 const struct pkey_handler *h;
284 int rc = -ENODEV;
285
286 h = pkey_handler_get_keybased(key, keylen);
287 if (h && h->apqns_for_key)
288 rc = h->apqns_for_key(key, keylen, flags, apqns, nr_apqns,
289 xflags);
290 pkey_handler_put(h);
291
292 return rc;
293}
294EXPORT_SYMBOL(pkey_handler_apqns_for_key);
295
296int pkey_handler_apqns_for_keytype(enum pkey_key_type keysubtype,
297 u8 cur_mkvp[32], u8 alt_mkvp[32], u32 flags,
298 struct pkey_apqn *apqns, size_t *nr_apqns,
299 u32 xflags)
300{
301 const struct pkey_handler *h;
302 int rc = -ENODEV;
303
304 h = pkey_handler_get_keytypebased(keysubtype);
305 if (h && h->apqns_for_keytype) {
306 rc = h->apqns_for_keytype(keysubtype,
307 cur_mkvp, alt_mkvp, flags,
308 apqns, nr_apqns, xflags);
309 }
310 pkey_handler_put(h);
311
312 return rc;
313}
314EXPORT_SYMBOL(pkey_handler_apqns_for_keytype);
315
316void pkey_handler_request_modules(void)
317{
318#ifdef CONFIG_MODULES
319 static const char * const pkey_handler_modules[] = {
320#if IS_MODULE(CONFIG_PKEY_CCA)
321 "pkey_cca",
322#endif
323#if IS_MODULE(CONFIG_PKEY_EP11)
324 "pkey_ep11",
325#endif
326#if IS_MODULE(CONFIG_PKEY_PCKMO)
327 "pkey_pckmo",
328#endif
329#if IS_MODULE(CONFIG_PKEY_UV)
330 "pkey_uv",
331#endif
332 };
333 int i;
334
335 for (i = 0; i < ARRAY_SIZE(pkey_handler_modules); i++) {
336 const struct pkey_handler *h;
337 bool found = false;
338
339 rcu_read_lock();
340 list_for_each_entry_rcu(h, &handler_list, list) {
341 if (h->module &&
342 !strcmp(h->module->name, pkey_handler_modules[i])) {
343 found = true;
344 break;
345 }
346 }
347 rcu_read_unlock();
348 if (!found) {
349 pr_debug("request_module(%s)\n", pkey_handler_modules[i]);
350 request_module(pkey_handler_modules[i]);
351 }
352 }
353#endif
354}
355EXPORT_SYMBOL(pkey_handler_request_modules);
356
357/*
358 * Module init
359 */
360static int __init pkey_init(void)
361{
362 int rc;
363
364 /* init debug feature */
365 pkey_dbf_info = debug_register("pkey", 1, 1, 5 * sizeof(long));
366 debug_register_view(pkey_dbf_info, &debug_sprintf_view);
367 debug_set_level(pkey_dbf_info, 4);
368
369 /* the handler registry does not need any init */
370
371 rc = pkey_api_init();
372 if (rc)
373 debug_unregister(pkey_dbf_info);
374
375 return rc;
376}
377
378/*
379 * Module exit
380 */
381static void __exit pkey_exit(void)
382{
383 pkey_api_exit();
384}
385
386module_cpu_feature_match(S390_CPU_FEATURE_MSA, pkey_init);
387module_exit(pkey_exit);