~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/arch/powerpc/kernel/security.c

Version: ~ [ linux-5.7 ] ~ [ linux-5.6.15 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.43 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.125 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.182 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.225 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.225 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.84 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 // SPDX-License-Identifier: GPL-2.0+
  2 //
  3 // Security related flags and so on.
  4 //
  5 // Copyright 2018, Michael Ellerman, IBM Corporation.
  6 
  7 #include <linux/kernel.h>
  8 #include <linux/device.h>
  9 #include <linux/seq_buf.h>
 10 
 11 #include <asm/asm-prototypes.h>
 12 #include <asm/code-patching.h>
 13 #include <asm/debugfs.h>
 14 #include <asm/security_features.h>
 15 #include <asm/setup.h>
 16 
 17 
 18 unsigned long powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;
 19 
 20 enum count_cache_flush_type {
 21         COUNT_CACHE_FLUSH_NONE  = 0x1,
 22         COUNT_CACHE_FLUSH_SW    = 0x2,
 23         COUNT_CACHE_FLUSH_HW    = 0x4,
 24 };
 25 static enum count_cache_flush_type count_cache_flush_type = COUNT_CACHE_FLUSH_NONE;
 26 
 27 bool barrier_nospec_enabled;
 28 static bool no_nospec;
 29 
 30 static void enable_barrier_nospec(bool enable)
 31 {
 32         barrier_nospec_enabled = enable;
 33         do_barrier_nospec_fixups(enable);
 34 }
 35 
 36 void setup_barrier_nospec(void)
 37 {
 38         bool enable;
 39 
 40         /*
 41          * It would make sense to check SEC_FTR_SPEC_BAR_ORI31 below as well.
 42          * But there's a good reason not to. The two flags we check below are
 43          * both are enabled by default in the kernel, so if the hcall is not
 44          * functional they will be enabled.
 45          * On a system where the host firmware has been updated (so the ori
 46          * functions as a barrier), but on which the hypervisor (KVM/Qemu) has
 47          * not been updated, we would like to enable the barrier. Dropping the
 48          * check for SEC_FTR_SPEC_BAR_ORI31 achieves that. The only downside is
 49          * we potentially enable the barrier on systems where the host firmware
 50          * is not updated, but that's harmless as it's a no-op.
 51          */
 52         enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
 53                  security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR);
 54 
 55         if (!no_nospec)
 56                 enable_barrier_nospec(enable);
 57 }
 58 
 59 static int __init handle_nospectre_v1(char *p)
 60 {
 61         no_nospec = true;
 62 
 63         return 0;
 64 }
 65 early_param("nospectre_v1", handle_nospectre_v1);
 66 
 67 #ifdef CONFIG_DEBUG_FS
 68 static int barrier_nospec_set(void *data, u64 val)
 69 {
 70         switch (val) {
 71         case 0:
 72         case 1:
 73                 break;
 74         default:
 75                 return -EINVAL;
 76         }
 77 
 78         if (!!val == !!barrier_nospec_enabled)
 79                 return 0;
 80 
 81         enable_barrier_nospec(!!val);
 82 
 83         return 0;
 84 }
 85 
 86 static int barrier_nospec_get(void *data, u64 *val)
 87 {
 88         *val = barrier_nospec_enabled ? 1 : 0;
 89         return 0;
 90 }
 91 
 92 DEFINE_SIMPLE_ATTRIBUTE(fops_barrier_nospec,
 93                         barrier_nospec_get, barrier_nospec_set, "%llu\n");
 94 
 95 static __init int barrier_nospec_debugfs_init(void)
 96 {
 97         debugfs_create_file("barrier_nospec", 0600, powerpc_debugfs_root, NULL,
 98                             &fops_barrier_nospec);
 99         return 0;
100 }
101 device_initcall(barrier_nospec_debugfs_init);
102 #endif /* CONFIG_DEBUG_FS */
103 
104 #ifdef CONFIG_PPC_BOOK3S_64
105 ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
106 {
107         bool thread_priv;
108 
109         thread_priv = security_ftr_enabled(SEC_FTR_L1D_THREAD_PRIV);
110 
111         if (rfi_flush || thread_priv) {
112                 struct seq_buf s;
113                 seq_buf_init(&s, buf, PAGE_SIZE - 1);
114 
115                 seq_buf_printf(&s, "Mitigation: ");
116 
117                 if (rfi_flush)
118                         seq_buf_printf(&s, "RFI Flush");
119 
120                 if (rfi_flush && thread_priv)
121                         seq_buf_printf(&s, ", ");
122 
123                 if (thread_priv)
124                         seq_buf_printf(&s, "L1D private per thread");
125 
126                 seq_buf_printf(&s, "\n");
127 
128                 return s.len;
129         }
130 
131         if (!security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) &&
132             !security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR))
133                 return sprintf(buf, "Not affected\n");
134 
135         return sprintf(buf, "Vulnerable\n");
136 }
137 #endif
138 
139 ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf)
140 {
141         struct seq_buf s;
142 
143         seq_buf_init(&s, buf, PAGE_SIZE - 1);
144 
145         if (security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR)) {
146                 if (barrier_nospec_enabled)
147                         seq_buf_printf(&s, "Mitigation: __user pointer sanitization");
148                 else
149                         seq_buf_printf(&s, "Vulnerable");
150 
151                 if (security_ftr_enabled(SEC_FTR_SPEC_BAR_ORI31))
152                         seq_buf_printf(&s, ", ori31 speculation barrier enabled");
153 
154                 seq_buf_printf(&s, "\n");
155         } else
156                 seq_buf_printf(&s, "Not affected\n");
157 
158         return s.len;
159 }
160 
161 ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf)
162 {
163         struct seq_buf s;
164         bool bcs, ccd;
165 
166         seq_buf_init(&s, buf, PAGE_SIZE - 1);
167 
168         bcs = security_ftr_enabled(SEC_FTR_BCCTRL_SERIALISED);
169         ccd = security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED);
170 
171         if (bcs || ccd || count_cache_flush_type != COUNT_CACHE_FLUSH_NONE) {
172                 bool comma = false;
173                 seq_buf_printf(&s, "Mitigation: ");
174 
175                 if (bcs) {
176                         seq_buf_printf(&s, "Indirect branch serialisation (kernel only)");
177                         comma = true;
178                 }
179 
180                 if (ccd) {
181                         if (comma)
182                                 seq_buf_printf(&s, ", ");
183                         seq_buf_printf(&s, "Indirect branch cache disabled");
184                         comma = true;
185                 }
186 
187                 if (comma)
188                         seq_buf_printf(&s, ", ");
189 
190                 seq_buf_printf(&s, "Software count cache flush");
191 
192                 if (count_cache_flush_type == COUNT_CACHE_FLUSH_HW)
193                         seq_buf_printf(&s, "(hardware accelerated)");
194         } else
195                 seq_buf_printf(&s, "Vulnerable");
196 
197         seq_buf_printf(&s, "\n");
198 
199         return s.len;
200 }
201 
202 #ifdef CONFIG_PPC_BOOK3S_64
203 /*
204  * Store-forwarding barrier support.
205  */
206 
207 static enum stf_barrier_type stf_enabled_flush_types;
208 static bool no_stf_barrier;
209 bool stf_barrier;
210 
211 static int __init handle_no_stf_barrier(char *p)
212 {
213         pr_info("stf-barrier: disabled on command line.");
214         no_stf_barrier = true;
215         return 0;
216 }
217 
218 early_param("no_stf_barrier", handle_no_stf_barrier);
219 
220 /* This is the generic flag used by other architectures */
221 static int __init handle_ssbd(char *p)
222 {
223         if (!p || strncmp(p, "auto", 5) == 0 || strncmp(p, "on", 2) == 0 ) {
224                 /* Until firmware tells us, we have the barrier with auto */
225                 return 0;
226         } else if (strncmp(p, "off", 3) == 0) {
227                 handle_no_stf_barrier(NULL);
228                 return 0;
229         } else
230                 return 1;
231 
232         return 0;
233 }
234 early_param("spec_store_bypass_disable", handle_ssbd);
235 
236 /* This is the generic flag used by other architectures */
237 static int __init handle_no_ssbd(char *p)
238 {
239         handle_no_stf_barrier(NULL);
240         return 0;
241 }
242 early_param("nospec_store_bypass_disable", handle_no_ssbd);
243 
244 static void stf_barrier_enable(bool enable)
245 {
246         if (enable)
247                 do_stf_barrier_fixups(stf_enabled_flush_types);
248         else
249                 do_stf_barrier_fixups(STF_BARRIER_NONE);
250 
251         stf_barrier = enable;
252 }
253 
254 void setup_stf_barrier(void)
255 {
256         enum stf_barrier_type type;
257         bool enable, hv;
258 
259         hv = cpu_has_feature(CPU_FTR_HVMODE);
260 
261         /* Default to fallback in case fw-features are not available */
262         if (cpu_has_feature(CPU_FTR_ARCH_300))
263                 type = STF_BARRIER_EIEIO;
264         else if (cpu_has_feature(CPU_FTR_ARCH_207S))
265                 type = STF_BARRIER_SYNC_ORI;
266         else if (cpu_has_feature(CPU_FTR_ARCH_206))
267                 type = STF_BARRIER_FALLBACK;
268         else
269                 type = STF_BARRIER_NONE;
270 
271         enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
272                 (security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR) ||
273                  (security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) && hv));
274 
275         if (type == STF_BARRIER_FALLBACK) {
276                 pr_info("stf-barrier: fallback barrier available\n");
277         } else if (type == STF_BARRIER_SYNC_ORI) {
278                 pr_info("stf-barrier: hwsync barrier available\n");
279         } else if (type == STF_BARRIER_EIEIO) {
280                 pr_info("stf-barrier: eieio barrier available\n");
281         }
282 
283         stf_enabled_flush_types = type;
284 
285         if (!no_stf_barrier)
286                 stf_barrier_enable(enable);
287 }
288 
289 ssize_t cpu_show_spec_store_bypass(struct device *dev, struct device_attribute *attr, char *buf)
290 {
291         if (stf_barrier && stf_enabled_flush_types != STF_BARRIER_NONE) {
292                 const char *type;
293                 switch (stf_enabled_flush_types) {
294                 case STF_BARRIER_EIEIO:
295                         type = "eieio";
296                         break;
297                 case STF_BARRIER_SYNC_ORI:
298                         type = "hwsync";
299                         break;
300                 case STF_BARRIER_FALLBACK:
301                         type = "fallback";
302                         break;
303                 default:
304                         type = "unknown";
305                 }
306                 return sprintf(buf, "Mitigation: Kernel entry/exit barrier (%s)\n", type);
307         }
308 
309         if (!security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) &&
310             !security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR))
311                 return sprintf(buf, "Not affected\n");
312 
313         return sprintf(buf, "Vulnerable\n");
314 }
315 
316 #ifdef CONFIG_DEBUG_FS
317 static int stf_barrier_set(void *data, u64 val)
318 {
319         bool enable;
320 
321         if (val == 1)
322                 enable = true;
323         else if (val == 0)
324                 enable = false;
325         else
326                 return -EINVAL;
327 
328         /* Only do anything if we're changing state */
329         if (enable != stf_barrier)
330                 stf_barrier_enable(enable);
331 
332         return 0;
333 }
334 
335 static int stf_barrier_get(void *data, u64 *val)
336 {
337         *val = stf_barrier ? 1 : 0;
338         return 0;
339 }
340 
341 DEFINE_SIMPLE_ATTRIBUTE(fops_stf_barrier, stf_barrier_get, stf_barrier_set, "%llu\n");
342 
343 static __init int stf_barrier_debugfs_init(void)
344 {
345         debugfs_create_file("stf_barrier", 0600, powerpc_debugfs_root, NULL, &fops_stf_barrier);
346         return 0;
347 }
348 device_initcall(stf_barrier_debugfs_init);
349 #endif /* CONFIG_DEBUG_FS */
350 
351 static void toggle_count_cache_flush(bool enable)
352 {
353         if (!enable || !security_ftr_enabled(SEC_FTR_FLUSH_COUNT_CACHE)) {
354                 patch_instruction_site(&patch__call_flush_count_cache, PPC_INST_NOP);
355                 count_cache_flush_type = COUNT_CACHE_FLUSH_NONE;
356                 pr_info("count-cache-flush: software flush disabled.\n");
357                 return;
358         }
359 
360         patch_branch_site(&patch__call_flush_count_cache,
361                           (u64)&flush_count_cache, BRANCH_SET_LINK);
362 
363         if (!security_ftr_enabled(SEC_FTR_BCCTR_FLUSH_ASSIST)) {
364                 count_cache_flush_type = COUNT_CACHE_FLUSH_SW;
365                 pr_info("count-cache-flush: full software flush sequence enabled.\n");
366                 return;
367         }
368 
369         patch_instruction_site(&patch__flush_count_cache_return, PPC_INST_BLR);
370         count_cache_flush_type = COUNT_CACHE_FLUSH_HW;
371         pr_info("count-cache-flush: hardware assisted flush sequence enabled\n");
372 }
373 
374 void setup_count_cache_flush(void)
375 {
376         toggle_count_cache_flush(true);
377 }
378 
379 #ifdef CONFIG_DEBUG_FS
380 static int count_cache_flush_set(void *data, u64 val)
381 {
382         bool enable;
383 
384         if (val == 1)
385                 enable = true;
386         else if (val == 0)
387                 enable = false;
388         else
389                 return -EINVAL;
390 
391         toggle_count_cache_flush(enable);
392 
393         return 0;
394 }
395 
396 static int count_cache_flush_get(void *data, u64 *val)
397 {
398         if (count_cache_flush_type == COUNT_CACHE_FLUSH_NONE)
399                 *val = 0;
400         else
401                 *val = 1;
402 
403         return 0;
404 }
405 
406 DEFINE_SIMPLE_ATTRIBUTE(fops_count_cache_flush, count_cache_flush_get,
407                         count_cache_flush_set, "%llu\n");
408 
409 static __init int count_cache_flush_debugfs_init(void)
410 {
411         debugfs_create_file("count_cache_flush", 0600, powerpc_debugfs_root,
412                             NULL, &fops_count_cache_flush);
413         return 0;
414 }
415 device_initcall(count_cache_flush_debugfs_init);
416 #endif /* CONFIG_DEBUG_FS */
417 #endif /* CONFIG_PPC_BOOK3S_64 */
418 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp