This source file includes following definitions.
- dump_prot
- note_prot_wx
- note_page
- walk_pte
- get_domain_name
- walk_pmd
- walk_pud
- walk_pgd
- ptdump_walk_pgd
- ptdump_initialize
- ptdump_check_wx
- ptdump_init
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11 #include <linux/debugfs.h>
12 #include <linux/fs.h>
13 #include <linux/mm.h>
14 #include <linux/seq_file.h>
15
16 #include <asm/domain.h>
17 #include <asm/fixmap.h>
18 #include <asm/memory.h>
19 #include <asm/pgtable.h>
20 #include <asm/ptdump.h>
21
22 static struct addr_marker address_markers[] = {
23 { MODULES_VADDR, "Modules" },
24 { PAGE_OFFSET, "Kernel Mapping" },
25 { 0, "vmalloc() Area" },
26 { VMALLOC_END, "vmalloc() End" },
27 { FIXADDR_START, "Fixmap Area" },
28 { VECTORS_BASE, "Vectors" },
29 { VECTORS_BASE + PAGE_SIZE * 2, "Vectors End" },
30 { -1, NULL },
31 };
32
33 #define pt_dump_seq_printf(m, fmt, args...) \
34 ({ \
35 if (m) \
36 seq_printf(m, fmt, ##args); \
37 })
38
39 #define pt_dump_seq_puts(m, fmt) \
40 ({ \
41 if (m) \
42 seq_printf(m, fmt); \
43 })
44
45 struct pg_state {
46 struct seq_file *seq;
47 const struct addr_marker *marker;
48 unsigned long start_address;
49 unsigned level;
50 u64 current_prot;
51 bool check_wx;
52 unsigned long wx_pages;
53 const char *current_domain;
54 };
55
56 struct prot_bits {
57 u64 mask;
58 u64 val;
59 const char *set;
60 const char *clear;
61 bool ro_bit;
62 bool nx_bit;
63 };
64
65 static const struct prot_bits pte_bits[] = {
66 {
67 .mask = L_PTE_USER,
68 .val = L_PTE_USER,
69 .set = "USR",
70 .clear = " ",
71 }, {
72 .mask = L_PTE_RDONLY,
73 .val = L_PTE_RDONLY,
74 .set = "ro",
75 .clear = "RW",
76 .ro_bit = true,
77 }, {
78 .mask = L_PTE_XN,
79 .val = L_PTE_XN,
80 .set = "NX",
81 .clear = "x ",
82 .nx_bit = true,
83 }, {
84 .mask = L_PTE_SHARED,
85 .val = L_PTE_SHARED,
86 .set = "SHD",
87 .clear = " ",
88 }, {
89 .mask = L_PTE_MT_MASK,
90 .val = L_PTE_MT_UNCACHED,
91 .set = "SO/UNCACHED",
92 }, {
93 .mask = L_PTE_MT_MASK,
94 .val = L_PTE_MT_BUFFERABLE,
95 .set = "MEM/BUFFERABLE/WC",
96 }, {
97 .mask = L_PTE_MT_MASK,
98 .val = L_PTE_MT_WRITETHROUGH,
99 .set = "MEM/CACHED/WT",
100 }, {
101 .mask = L_PTE_MT_MASK,
102 .val = L_PTE_MT_WRITEBACK,
103 .set = "MEM/CACHED/WBRA",
104 #ifndef CONFIG_ARM_LPAE
105 }, {
106 .mask = L_PTE_MT_MASK,
107 .val = L_PTE_MT_MINICACHE,
108 .set = "MEM/MINICACHE",
109 #endif
110 }, {
111 .mask = L_PTE_MT_MASK,
112 .val = L_PTE_MT_WRITEALLOC,
113 .set = "MEM/CACHED/WBWA",
114 }, {
115 .mask = L_PTE_MT_MASK,
116 .val = L_PTE_MT_DEV_SHARED,
117 .set = "DEV/SHARED",
118 #ifndef CONFIG_ARM_LPAE
119 }, {
120 .mask = L_PTE_MT_MASK,
121 .val = L_PTE_MT_DEV_NONSHARED,
122 .set = "DEV/NONSHARED",
123 #endif
124 }, {
125 .mask = L_PTE_MT_MASK,
126 .val = L_PTE_MT_DEV_WC,
127 .set = "DEV/WC",
128 }, {
129 .mask = L_PTE_MT_MASK,
130 .val = L_PTE_MT_DEV_CACHED,
131 .set = "DEV/CACHED",
132 },
133 };
134
135 static const struct prot_bits section_bits[] = {
136 #ifdef CONFIG_ARM_LPAE
137 {
138 .mask = PMD_SECT_USER,
139 .val = PMD_SECT_USER,
140 .set = "USR",
141 }, {
142 .mask = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
143 .val = L_PMD_SECT_RDONLY | PMD_SECT_AP2,
144 .set = "ro",
145 .clear = "RW",
146 .ro_bit = true,
147 #elif __LINUX_ARM_ARCH__ >= 6
148 {
149 .mask = PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
150 .val = PMD_SECT_APX | PMD_SECT_AP_WRITE,
151 .set = " ro",
152 .ro_bit = true,
153 }, {
154 .mask = PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
155 .val = PMD_SECT_AP_WRITE,
156 .set = " RW",
157 }, {
158 .mask = PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
159 .val = PMD_SECT_AP_READ,
160 .set = "USR ro",
161 }, {
162 .mask = PMD_SECT_APX | PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
163 .val = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
164 .set = "USR RW",
165 #else
166
167 {
168 .mask = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
169 .val = 0,
170 .set = " ro",
171 .ro_bit = true,
172 }, {
173 .mask = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
174 .val = PMD_SECT_AP_WRITE,
175 .set = " RW",
176 }, {
177 .mask = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
178 .val = PMD_SECT_AP_READ,
179 .set = "USR ro",
180 }, {
181 .mask = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
182 .val = PMD_SECT_AP_READ | PMD_SECT_AP_WRITE,
183 .set = "USR RW",
184 #endif
185 }, {
186 .mask = PMD_SECT_XN,
187 .val = PMD_SECT_XN,
188 .set = "NX",
189 .clear = "x ",
190 .nx_bit = true,
191 }, {
192 .mask = PMD_SECT_S,
193 .val = PMD_SECT_S,
194 .set = "SHD",
195 .clear = " ",
196 },
197 };
198
199 struct pg_level {
200 const struct prot_bits *bits;
201 size_t num;
202 u64 mask;
203 const struct prot_bits *ro_bit;
204 const struct prot_bits *nx_bit;
205 };
206
207 static struct pg_level pg_level[] = {
208 {
209 }, {
210 }, {
211 }, {
212 .bits = section_bits,
213 .num = ARRAY_SIZE(section_bits),
214 }, {
215 .bits = pte_bits,
216 .num = ARRAY_SIZE(pte_bits),
217 },
218 };
219
220 static void dump_prot(struct pg_state *st, const struct prot_bits *bits, size_t num)
221 {
222 unsigned i;
223
224 for (i = 0; i < num; i++, bits++) {
225 const char *s;
226
227 if ((st->current_prot & bits->mask) == bits->val)
228 s = bits->set;
229 else
230 s = bits->clear;
231
232 if (s)
233 pt_dump_seq_printf(st->seq, " %s", s);
234 }
235 }
236
237 static void note_prot_wx(struct pg_state *st, unsigned long addr)
238 {
239 if (!st->check_wx)
240 return;
241 if ((st->current_prot & pg_level[st->level].ro_bit->mask) ==
242 pg_level[st->level].ro_bit->val)
243 return;
244 if ((st->current_prot & pg_level[st->level].nx_bit->mask) ==
245 pg_level[st->level].nx_bit->val)
246 return;
247
248 WARN_ONCE(1, "arm/mm: Found insecure W+X mapping at address %pS\n",
249 (void *)st->start_address);
250
251 st->wx_pages += (addr - st->start_address) / PAGE_SIZE;
252 }
253
254 static void note_page(struct pg_state *st, unsigned long addr,
255 unsigned int level, u64 val, const char *domain)
256 {
257 static const char units[] = "KMGTPE";
258 u64 prot = val & pg_level[level].mask;
259
260 if (!st->level) {
261 st->level = level;
262 st->current_prot = prot;
263 st->current_domain = domain;
264 pt_dump_seq_printf(st->seq, "---[ %s ]---\n", st->marker->name);
265 } else if (prot != st->current_prot || level != st->level ||
266 domain != st->current_domain ||
267 addr >= st->marker[1].start_address) {
268 const char *unit = units;
269 unsigned long delta;
270
271 if (st->current_prot) {
272 note_prot_wx(st, addr);
273 pt_dump_seq_printf(st->seq, "0x%08lx-0x%08lx ",
274 st->start_address, addr);
275
276 delta = (addr - st->start_address) >> 10;
277 while (!(delta & 1023) && unit[1]) {
278 delta >>= 10;
279 unit++;
280 }
281 pt_dump_seq_printf(st->seq, "%9lu%c", delta, *unit);
282 if (st->current_domain)
283 pt_dump_seq_printf(st->seq, " %s",
284 st->current_domain);
285 if (pg_level[st->level].bits)
286 dump_prot(st, pg_level[st->level].bits, pg_level[st->level].num);
287 pt_dump_seq_printf(st->seq, "\n");
288 }
289
290 if (addr >= st->marker[1].start_address) {
291 st->marker++;
292 pt_dump_seq_printf(st->seq, "---[ %s ]---\n",
293 st->marker->name);
294 }
295 st->start_address = addr;
296 st->current_prot = prot;
297 st->current_domain = domain;
298 st->level = level;
299 }
300 }
301
302 static void walk_pte(struct pg_state *st, pmd_t *pmd, unsigned long start,
303 const char *domain)
304 {
305 pte_t *pte = pte_offset_kernel(pmd, 0);
306 unsigned long addr;
307 unsigned i;
308
309 for (i = 0; i < PTRS_PER_PTE; i++, pte++) {
310 addr = start + i * PAGE_SIZE;
311 note_page(st, addr, 4, pte_val(*pte), domain);
312 }
313 }
314
315 static const char *get_domain_name(pmd_t *pmd)
316 {
317 #ifndef CONFIG_ARM_LPAE
318 switch (pmd_val(*pmd) & PMD_DOMAIN_MASK) {
319 case PMD_DOMAIN(DOMAIN_KERNEL):
320 return "KERNEL ";
321 case PMD_DOMAIN(DOMAIN_USER):
322 return "USER ";
323 case PMD_DOMAIN(DOMAIN_IO):
324 return "IO ";
325 case PMD_DOMAIN(DOMAIN_VECTORS):
326 return "VECTORS";
327 default:
328 return "unknown";
329 }
330 #endif
331 return NULL;
332 }
333
334 static void walk_pmd(struct pg_state *st, pud_t *pud, unsigned long start)
335 {
336 pmd_t *pmd = pmd_offset(pud, 0);
337 unsigned long addr;
338 unsigned i;
339 const char *domain;
340
341 for (i = 0; i < PTRS_PER_PMD; i++, pmd++) {
342 addr = start + i * PMD_SIZE;
343 domain = get_domain_name(pmd);
344 if (pmd_none(*pmd) || pmd_large(*pmd) || !pmd_present(*pmd))
345 note_page(st, addr, 3, pmd_val(*pmd), domain);
346 else
347 walk_pte(st, pmd, addr, domain);
348
349 if (SECTION_SIZE < PMD_SIZE && pmd_large(pmd[1])) {
350 addr += SECTION_SIZE;
351 pmd++;
352 domain = get_domain_name(pmd);
353 note_page(st, addr, 3, pmd_val(*pmd), domain);
354 }
355 }
356 }
357
358 static void walk_pud(struct pg_state *st, pgd_t *pgd, unsigned long start)
359 {
360 pud_t *pud = pud_offset(pgd, 0);
361 unsigned long addr;
362 unsigned i;
363
364 for (i = 0; i < PTRS_PER_PUD; i++, pud++) {
365 addr = start + i * PUD_SIZE;
366 if (!pud_none(*pud)) {
367 walk_pmd(st, pud, addr);
368 } else {
369 note_page(st, addr, 2, pud_val(*pud), NULL);
370 }
371 }
372 }
373
374 static void walk_pgd(struct pg_state *st, struct mm_struct *mm,
375 unsigned long start)
376 {
377 pgd_t *pgd = pgd_offset(mm, 0UL);
378 unsigned i;
379 unsigned long addr;
380
381 for (i = 0; i < PTRS_PER_PGD; i++, pgd++) {
382 addr = start + i * PGDIR_SIZE;
383 if (!pgd_none(*pgd)) {
384 walk_pud(st, pgd, addr);
385 } else {
386 note_page(st, addr, 1, pgd_val(*pgd), NULL);
387 }
388 }
389 }
390
391 void ptdump_walk_pgd(struct seq_file *m, struct ptdump_info *info)
392 {
393 struct pg_state st = {
394 .seq = m,
395 .marker = info->markers,
396 .check_wx = false,
397 };
398
399 walk_pgd(&st, info->mm, info->base_addr);
400 note_page(&st, 0, 0, 0, NULL);
401 }
402
403 static void ptdump_initialize(void)
404 {
405 unsigned i, j;
406
407 for (i = 0; i < ARRAY_SIZE(pg_level); i++)
408 if (pg_level[i].bits)
409 for (j = 0; j < pg_level[i].num; j++) {
410 pg_level[i].mask |= pg_level[i].bits[j].mask;
411 if (pg_level[i].bits[j].ro_bit)
412 pg_level[i].ro_bit = &pg_level[i].bits[j];
413 if (pg_level[i].bits[j].nx_bit)
414 pg_level[i].nx_bit = &pg_level[i].bits[j];
415 }
416
417 address_markers[2].start_address = VMALLOC_START;
418 }
419
420 static struct ptdump_info kernel_ptdump_info = {
421 .mm = &init_mm,
422 .markers = address_markers,
423 .base_addr = 0,
424 };
425
426 void ptdump_check_wx(void)
427 {
428 struct pg_state st = {
429 .seq = NULL,
430 .marker = (struct addr_marker[]) {
431 { 0, NULL},
432 { -1, NULL},
433 },
434 .check_wx = true,
435 };
436
437 walk_pgd(&st, &init_mm, 0);
438 note_page(&st, 0, 0, 0, NULL);
439 if (st.wx_pages)
440 pr_warn("Checked W+X mappings: FAILED, %lu W+X pages found\n",
441 st.wx_pages);
442 else
443 pr_info("Checked W+X mappings: passed, no W+X pages found\n");
444 }
445
446 static int ptdump_init(void)
447 {
448 ptdump_initialize();
449 ptdump_debugfs_register(&kernel_ptdump_info, "kernel_page_tables");
450 return 0;
451 }
452 __initcall(ptdump_init);