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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
014dc90b AL |
2 | /* |
3 | * ldt_gdt.c - Test cases for LDT and GDT access | |
4 | * Copyright (c) 2015 Andrew Lutomirski | |
5 | */ | |
6 | ||
7 | #define _GNU_SOURCE | |
8 | #include <err.h> | |
9 | #include <stdio.h> | |
10 | #include <stdint.h> | |
11 | #include <signal.h> | |
12 | #include <setjmp.h> | |
13 | #include <stdlib.h> | |
14 | #include <string.h> | |
15 | #include <errno.h> | |
16 | #include <unistd.h> | |
17 | #include <sys/syscall.h> | |
18 | #include <asm/ldt.h> | |
19 | #include <sys/types.h> | |
20 | #include <sys/wait.h> | |
21 | #include <stdbool.h> | |
22 | #include <pthread.h> | |
23 | #include <sched.h> | |
24 | #include <linux/futex.h> | |
d63f4b52 AL |
25 | #include <sys/mman.h> |
26 | #include <asm/prctl.h> | |
27 | #include <sys/prctl.h> | |
014dc90b AL |
28 | |
29 | #define AR_ACCESSED (1<<8) | |
30 | ||
31 | #define AR_TYPE_RODATA (0 * (1<<9)) | |
32 | #define AR_TYPE_RWDATA (1 * (1<<9)) | |
33 | #define AR_TYPE_RODATA_EXPDOWN (2 * (1<<9)) | |
34 | #define AR_TYPE_RWDATA_EXPDOWN (3 * (1<<9)) | |
35 | #define AR_TYPE_XOCODE (4 * (1<<9)) | |
36 | #define AR_TYPE_XRCODE (5 * (1<<9)) | |
37 | #define AR_TYPE_XOCODE_CONF (6 * (1<<9)) | |
38 | #define AR_TYPE_XRCODE_CONF (7 * (1<<9)) | |
39 | ||
40 | #define AR_DPL3 (3 * (1<<13)) | |
41 | ||
42 | #define AR_S (1 << 12) | |
43 | #define AR_P (1 << 15) | |
44 | #define AR_AVL (1 << 20) | |
45 | #define AR_L (1 << 21) | |
46 | #define AR_DB (1 << 22) | |
47 | #define AR_G (1 << 23) | |
48 | ||
2a4d0c62 DS |
49 | #ifdef __x86_64__ |
50 | # define INT80_CLOBBERS "r8", "r9", "r10", "r11" | |
51 | #else | |
52 | # define INT80_CLOBBERS | |
53 | #endif | |
54 | ||
014dc90b AL |
55 | static int nerrs; |
56 | ||
d63f4b52 AL |
57 | /* Points to an array of 1024 ints, each holding its own index. */ |
58 | static const unsigned int *counter_page; | |
59 | static struct user_desc *low_user_desc; | |
60 | static struct user_desc *low_user_desc_clear; /* Use to delete GDT entry */ | |
61 | static int gdt_entry_num; | |
62 | ||
014dc90b AL |
63 | static void check_invalid_segment(uint16_t index, int ldt) |
64 | { | |
65 | uint32_t has_limit = 0, has_ar = 0, limit, ar; | |
66 | uint32_t selector = (index << 3) | (ldt << 2) | 3; | |
67 | ||
68 | asm ("lsl %[selector], %[limit]\n\t" | |
69 | "jnz 1f\n\t" | |
70 | "movl $1, %[has_limit]\n\t" | |
71 | "1:" | |
72 | : [limit] "=r" (limit), [has_limit] "+rm" (has_limit) | |
73 | : [selector] "r" (selector)); | |
74 | asm ("larl %[selector], %[ar]\n\t" | |
75 | "jnz 1f\n\t" | |
76 | "movl $1, %[has_ar]\n\t" | |
77 | "1:" | |
78 | : [ar] "=r" (ar), [has_ar] "+rm" (has_ar) | |
79 | : [selector] "r" (selector)); | |
80 | ||
81 | if (has_limit || has_ar) { | |
82 | printf("[FAIL]\t%s entry %hu is valid but should be invalid\n", | |
83 | (ldt ? "LDT" : "GDT"), index); | |
84 | nerrs++; | |
85 | } else { | |
86 | printf("[OK]\t%s entry %hu is invalid\n", | |
87 | (ldt ? "LDT" : "GDT"), index); | |
88 | } | |
89 | } | |
90 | ||
91 | static void check_valid_segment(uint16_t index, int ldt, | |
92 | uint32_t expected_ar, uint32_t expected_limit, | |
93 | bool verbose) | |
94 | { | |
95 | uint32_t has_limit = 0, has_ar = 0, limit, ar; | |
96 | uint32_t selector = (index << 3) | (ldt << 2) | 3; | |
97 | ||
98 | asm ("lsl %[selector], %[limit]\n\t" | |
99 | "jnz 1f\n\t" | |
100 | "movl $1, %[has_limit]\n\t" | |
101 | "1:" | |
102 | : [limit] "=r" (limit), [has_limit] "+rm" (has_limit) | |
103 | : [selector] "r" (selector)); | |
104 | asm ("larl %[selector], %[ar]\n\t" | |
105 | "jnz 1f\n\t" | |
106 | "movl $1, %[has_ar]\n\t" | |
107 | "1:" | |
108 | : [ar] "=r" (ar), [has_ar] "+rm" (has_ar) | |
109 | : [selector] "r" (selector)); | |
110 | ||
111 | if (!has_limit || !has_ar) { | |
112 | printf("[FAIL]\t%s entry %hu is invalid but should be valid\n", | |
113 | (ldt ? "LDT" : "GDT"), index); | |
114 | nerrs++; | |
115 | return; | |
116 | } | |
117 | ||
d60ad744 AL |
118 | /* The SDM says "bits 19:16 are undefined". Thanks. */ |
119 | ar &= ~0xF0000; | |
120 | ||
121 | /* | |
122 | * NB: Different Linux versions do different things with the | |
123 | * accessed bit in set_thread_area(). | |
124 | */ | |
9f5cb6b3 | 125 | if (ar != expected_ar && ar != (expected_ar | AR_ACCESSED)) { |
014dc90b AL |
126 | printf("[FAIL]\t%s entry %hu has AR 0x%08X but expected 0x%08X\n", |
127 | (ldt ? "LDT" : "GDT"), index, ar, expected_ar); | |
128 | nerrs++; | |
129 | } else if (limit != expected_limit) { | |
130 | printf("[FAIL]\t%s entry %hu has limit 0x%08X but expected 0x%08X\n", | |
131 | (ldt ? "LDT" : "GDT"), index, limit, expected_limit); | |
132 | nerrs++; | |
133 | } else if (verbose) { | |
134 | printf("[OK]\t%s entry %hu has AR 0x%08X and limit 0x%08X\n", | |
135 | (ldt ? "LDT" : "GDT"), index, ar, limit); | |
136 | } | |
137 | } | |
138 | ||
d744dcad AL |
139 | static bool install_valid_mode(const struct user_desc *d, uint32_t ar, |
140 | bool oldmode, bool ldt) | |
014dc90b | 141 | { |
d744dcad AL |
142 | struct user_desc desc = *d; |
143 | int ret; | |
144 | ||
145 | if (!ldt) { | |
146 | #ifndef __i386__ | |
147 | /* No point testing set_thread_area in a 64-bit build */ | |
148 | return false; | |
149 | #endif | |
150 | if (!gdt_entry_num) | |
151 | return false; | |
152 | desc.entry_number = gdt_entry_num; | |
153 | ||
154 | ret = syscall(SYS_set_thread_area, &desc); | |
155 | } else { | |
156 | ret = syscall(SYS_modify_ldt, oldmode ? 1 : 0x11, | |
157 | &desc, sizeof(desc)); | |
158 | ||
159 | if (ret < -1) | |
160 | errno = -ret; | |
161 | ||
162 | if (ret != 0 && errno == ENOSYS) { | |
163 | printf("[OK]\tmodify_ldt returned -ENOSYS\n"); | |
164 | return false; | |
165 | } | |
166 | } | |
167 | ||
014dc90b | 168 | if (ret == 0) { |
d744dcad AL |
169 | uint32_t limit = desc.limit; |
170 | if (desc.limit_in_pages) | |
014dc90b | 171 | limit = (limit << 12) + 4095; |
d744dcad | 172 | check_valid_segment(desc.entry_number, ldt, ar, limit, true); |
014dc90b | 173 | return true; |
014dc90b | 174 | } else { |
d744dcad AL |
175 | if (desc.seg_32bit) { |
176 | printf("[FAIL]\tUnexpected %s failure %d\n", | |
177 | ldt ? "modify_ldt" : "set_thread_area", | |
014dc90b AL |
178 | errno); |
179 | nerrs++; | |
180 | return false; | |
181 | } else { | |
d744dcad AL |
182 | printf("[OK]\t%s rejected 16 bit segment\n", |
183 | ldt ? "modify_ldt" : "set_thread_area"); | |
014dc90b AL |
184 | return false; |
185 | } | |
186 | } | |
187 | } | |
188 | ||
189 | static bool install_valid(const struct user_desc *desc, uint32_t ar) | |
190 | { | |
adedf289 AL |
191 | bool ret = install_valid_mode(desc, ar, false, true); |
192 | ||
193 | if (desc->contents <= 1 && desc->seg_32bit && | |
194 | !desc->seg_not_present) { | |
195 | /* Should work in the GDT, too. */ | |
196 | install_valid_mode(desc, ar, false, false); | |
197 | } | |
198 | ||
199 | return ret; | |
014dc90b AL |
200 | } |
201 | ||
202 | static void install_invalid(const struct user_desc *desc, bool oldmode) | |
203 | { | |
204 | int ret = syscall(SYS_modify_ldt, oldmode ? 1 : 0x11, | |
205 | desc, sizeof(*desc)); | |
206 | if (ret < -1) | |
207 | errno = -ret; | |
208 | if (ret == 0) { | |
209 | check_invalid_segment(desc->entry_number, 1); | |
210 | } else if (errno == ENOSYS) { | |
211 | printf("[OK]\tmodify_ldt returned -ENOSYS\n"); | |
212 | } else { | |
213 | if (desc->seg_32bit) { | |
214 | printf("[FAIL]\tUnexpected modify_ldt failure %d\n", | |
215 | errno); | |
216 | nerrs++; | |
217 | } else { | |
218 | printf("[OK]\tmodify_ldt rejected 16 bit segment\n"); | |
219 | } | |
220 | } | |
221 | } | |
222 | ||
223 | static int safe_modify_ldt(int func, struct user_desc *ptr, | |
224 | unsigned long bytecount) | |
225 | { | |
226 | int ret = syscall(SYS_modify_ldt, 0x11, ptr, bytecount); | |
227 | if (ret < -1) | |
228 | errno = -ret; | |
229 | return ret; | |
230 | } | |
231 | ||
232 | static void fail_install(struct user_desc *desc) | |
233 | { | |
234 | if (safe_modify_ldt(0x11, desc, sizeof(*desc)) == 0) { | |
235 | printf("[FAIL]\tmodify_ldt accepted a bad descriptor\n"); | |
236 | nerrs++; | |
237 | } else if (errno == ENOSYS) { | |
238 | printf("[OK]\tmodify_ldt returned -ENOSYS\n"); | |
239 | } else { | |
240 | printf("[OK]\tmodify_ldt failure %d\n", errno); | |
241 | } | |
242 | } | |
243 | ||
244 | static void do_simple_tests(void) | |
245 | { | |
246 | struct user_desc desc = { | |
247 | .entry_number = 0, | |
248 | .base_addr = 0, | |
249 | .limit = 10, | |
250 | .seg_32bit = 1, | |
251 | .contents = 2, /* Code, not conforming */ | |
252 | .read_exec_only = 0, | |
253 | .limit_in_pages = 0, | |
254 | .seg_not_present = 0, | |
255 | .useable = 0 | |
256 | }; | |
257 | install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE | AR_S | AR_P | AR_DB); | |
258 | ||
259 | desc.limit_in_pages = 1; | |
260 | install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE | | |
261 | AR_S | AR_P | AR_DB | AR_G); | |
262 | ||
263 | check_invalid_segment(1, 1); | |
264 | ||
265 | desc.entry_number = 2; | |
266 | install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE | | |
267 | AR_S | AR_P | AR_DB | AR_G); | |
268 | ||
269 | check_invalid_segment(1, 1); | |
270 | ||
271 | desc.base_addr = 0xf0000000; | |
272 | install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE | | |
273 | AR_S | AR_P | AR_DB | AR_G); | |
274 | ||
275 | desc.useable = 1; | |
276 | install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE | | |
277 | AR_S | AR_P | AR_DB | AR_G | AR_AVL); | |
278 | ||
279 | desc.seg_not_present = 1; | |
280 | install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE | | |
281 | AR_S | AR_DB | AR_G | AR_AVL); | |
282 | ||
283 | desc.seg_32bit = 0; | |
284 | install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE | | |
285 | AR_S | AR_G | AR_AVL); | |
286 | ||
287 | desc.seg_32bit = 1; | |
288 | desc.contents = 0; | |
289 | install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | | |
290 | AR_S | AR_DB | AR_G | AR_AVL); | |
291 | ||
292 | desc.read_exec_only = 1; | |
293 | install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | | |
294 | AR_S | AR_DB | AR_G | AR_AVL); | |
295 | ||
296 | desc.contents = 1; | |
297 | install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA_EXPDOWN | | |
298 | AR_S | AR_DB | AR_G | AR_AVL); | |
299 | ||
300 | desc.read_exec_only = 0; | |
301 | desc.limit_in_pages = 0; | |
302 | install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA_EXPDOWN | | |
303 | AR_S | AR_DB | AR_AVL); | |
304 | ||
305 | desc.contents = 3; | |
306 | install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE_CONF | | |
307 | AR_S | AR_DB | AR_AVL); | |
308 | ||
309 | desc.read_exec_only = 1; | |
310 | install_valid(&desc, AR_DPL3 | AR_TYPE_XOCODE_CONF | | |
311 | AR_S | AR_DB | AR_AVL); | |
312 | ||
313 | desc.read_exec_only = 0; | |
314 | desc.contents = 2; | |
315 | install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE | | |
316 | AR_S | AR_DB | AR_AVL); | |
317 | ||
318 | desc.read_exec_only = 1; | |
319 | ||
320 | #ifdef __x86_64__ | |
321 | desc.lm = 1; | |
322 | install_valid(&desc, AR_DPL3 | AR_TYPE_XOCODE | | |
323 | AR_S | AR_DB | AR_AVL); | |
324 | desc.lm = 0; | |
325 | #endif | |
326 | ||
327 | bool entry1_okay = install_valid(&desc, AR_DPL3 | AR_TYPE_XOCODE | | |
328 | AR_S | AR_DB | AR_AVL); | |
329 | ||
330 | if (entry1_okay) { | |
331 | printf("[RUN]\tTest fork\n"); | |
332 | pid_t child = fork(); | |
333 | if (child == 0) { | |
334 | nerrs = 0; | |
335 | check_valid_segment(desc.entry_number, 1, | |
336 | AR_DPL3 | AR_TYPE_XOCODE | | |
337 | AR_S | AR_DB | AR_AVL, desc.limit, | |
338 | true); | |
339 | check_invalid_segment(1, 1); | |
340 | exit(nerrs ? 1 : 0); | |
341 | } else { | |
342 | int status; | |
343 | if (waitpid(child, &status, 0) != child || | |
344 | !WIFEXITED(status)) { | |
345 | printf("[FAIL]\tChild died\n"); | |
346 | nerrs++; | |
347 | } else if (WEXITSTATUS(status) != 0) { | |
348 | printf("[FAIL]\tChild failed\n"); | |
349 | nerrs++; | |
350 | } else { | |
351 | printf("[OK]\tChild succeeded\n"); | |
352 | } | |
353 | } | |
354 | ||
355 | printf("[RUN]\tTest size\n"); | |
356 | int i; | |
357 | for (i = 0; i < 8192; i++) { | |
358 | desc.entry_number = i; | |
359 | desc.limit = i; | |
360 | if (safe_modify_ldt(0x11, &desc, sizeof(desc)) != 0) { | |
361 | printf("[FAIL]\tFailed to install entry %d\n", i); | |
362 | nerrs++; | |
363 | break; | |
364 | } | |
365 | } | |
366 | for (int j = 0; j < i; j++) { | |
367 | check_valid_segment(j, 1, AR_DPL3 | AR_TYPE_XOCODE | | |
368 | AR_S | AR_DB | AR_AVL, j, false); | |
369 | } | |
370 | printf("[DONE]\tSize test\n"); | |
371 | } else { | |
372 | printf("[SKIP]\tSkipping fork and size tests because we have no LDT\n"); | |
373 | } | |
374 | ||
375 | /* Test entry_number too high. */ | |
376 | desc.entry_number = 8192; | |
377 | fail_install(&desc); | |
378 | ||
379 | /* Test deletion and actions mistakeable for deletion. */ | |
380 | memset(&desc, 0, sizeof(desc)); | |
381 | install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S | AR_P); | |
382 | ||
383 | desc.seg_not_present = 1; | |
384 | install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S); | |
385 | ||
386 | desc.seg_not_present = 0; | |
387 | desc.read_exec_only = 1; | |
388 | install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | AR_S | AR_P); | |
389 | ||
390 | desc.read_exec_only = 0; | |
391 | desc.seg_not_present = 1; | |
392 | install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S); | |
393 | ||
394 | desc.read_exec_only = 1; | |
395 | desc.limit = 1; | |
396 | install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | AR_S); | |
397 | ||
398 | desc.limit = 0; | |
399 | desc.base_addr = 1; | |
400 | install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | AR_S); | |
401 | ||
402 | desc.base_addr = 0; | |
403 | install_invalid(&desc, false); | |
404 | ||
405 | desc.seg_not_present = 0; | |
014dc90b | 406 | desc.seg_32bit = 1; |
fec8f5ae AL |
407 | desc.read_exec_only = 0; |
408 | desc.limit = 0xfffff; | |
409 | ||
014dc90b | 410 | install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S | AR_P | AR_DB); |
fec8f5ae AL |
411 | |
412 | desc.limit_in_pages = 1; | |
413 | ||
414 | install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA | AR_S | AR_P | AR_DB | AR_G); | |
415 | desc.read_exec_only = 1; | |
416 | install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA | AR_S | AR_P | AR_DB | AR_G); | |
417 | desc.contents = 1; | |
418 | desc.read_exec_only = 0; | |
419 | install_valid(&desc, AR_DPL3 | AR_TYPE_RWDATA_EXPDOWN | AR_S | AR_P | AR_DB | AR_G); | |
420 | desc.read_exec_only = 1; | |
421 | install_valid(&desc, AR_DPL3 | AR_TYPE_RODATA_EXPDOWN | AR_S | AR_P | AR_DB | AR_G); | |
422 | ||
423 | desc.limit = 0; | |
014dc90b AL |
424 | install_invalid(&desc, true); |
425 | } | |
426 | ||
427 | /* | |
428 | * 0: thread is idle | |
429 | * 1: thread armed | |
430 | * 2: thread should clear LDT entry 0 | |
431 | * 3: thread should exit | |
432 | */ | |
433 | static volatile unsigned int ftx; | |
434 | ||
435 | static void *threadproc(void *ctx) | |
436 | { | |
437 | cpu_set_t cpuset; | |
438 | CPU_ZERO(&cpuset); | |
439 | CPU_SET(1, &cpuset); | |
440 | if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) | |
441 | err(1, "sched_setaffinity to CPU 1"); /* should never fail */ | |
442 | ||
443 | while (1) { | |
444 | syscall(SYS_futex, &ftx, FUTEX_WAIT, 0, NULL, NULL, 0); | |
445 | while (ftx != 2) { | |
446 | if (ftx >= 3) | |
447 | return NULL; | |
448 | } | |
449 | ||
450 | /* clear LDT entry 0 */ | |
451 | const struct user_desc desc = {}; | |
452 | if (syscall(SYS_modify_ldt, 1, &desc, sizeof(desc)) != 0) | |
453 | err(1, "modify_ldt"); | |
454 | ||
455 | /* If ftx == 2, set it to zero. If ftx == 100, quit. */ | |
456 | unsigned int x = -2; | |
457 | asm volatile ("lock xaddl %[x], %[ftx]" : | |
458 | [x] "+r" (x), [ftx] "+m" (ftx)); | |
459 | if (x != 2) | |
460 | return NULL; | |
461 | } | |
462 | } | |
463 | ||
65973dd3 AL |
464 | #ifdef __i386__ |
465 | ||
466 | #ifndef SA_RESTORE | |
467 | #define SA_RESTORER 0x04000000 | |
468 | #endif | |
469 | ||
470 | /* | |
471 | * The UAPI header calls this 'struct sigaction', which conflicts with | |
472 | * glibc. Sigh. | |
473 | */ | |
474 | struct fake_ksigaction { | |
475 | void *handler; /* the real type is nasty */ | |
476 | unsigned long sa_flags; | |
477 | void (*sa_restorer)(void); | |
478 | unsigned char sigset[8]; | |
479 | }; | |
480 | ||
481 | static void fix_sa_restorer(int sig) | |
482 | { | |
483 | struct fake_ksigaction ksa; | |
484 | ||
485 | if (syscall(SYS_rt_sigaction, sig, NULL, &ksa, 8) == 0) { | |
486 | /* | |
487 | * glibc has a nasty bug: it sometimes writes garbage to | |
488 | * sa_restorer. This interacts quite badly with anything | |
489 | * that fiddles with SS because it can trigger legacy | |
490 | * stack switching. Patch it up. See: | |
491 | * | |
492 | * https://sourceware.org/bugzilla/show_bug.cgi?id=21269 | |
493 | */ | |
494 | if (!(ksa.sa_flags & SA_RESTORER) && ksa.sa_restorer) { | |
495 | ksa.sa_restorer = NULL; | |
496 | if (syscall(SYS_rt_sigaction, sig, &ksa, NULL, | |
497 | sizeof(ksa.sigset)) != 0) | |
498 | err(1, "rt_sigaction"); | |
499 | } | |
500 | } | |
501 | } | |
502 | #else | |
503 | static void fix_sa_restorer(int sig) | |
504 | { | |
505 | /* 64-bit glibc works fine. */ | |
506 | } | |
507 | #endif | |
508 | ||
014dc90b AL |
509 | static void sethandler(int sig, void (*handler)(int, siginfo_t *, void *), |
510 | int flags) | |
511 | { | |
512 | struct sigaction sa; | |
513 | memset(&sa, 0, sizeof(sa)); | |
514 | sa.sa_sigaction = handler; | |
515 | sa.sa_flags = SA_SIGINFO | flags; | |
516 | sigemptyset(&sa.sa_mask); | |
517 | if (sigaction(sig, &sa, 0)) | |
518 | err(1, "sigaction"); | |
519 | ||
65973dd3 | 520 | fix_sa_restorer(sig); |
014dc90b AL |
521 | } |
522 | ||
523 | static jmp_buf jmpbuf; | |
524 | ||
525 | static void sigsegv(int sig, siginfo_t *info, void *ctx_void) | |
526 | { | |
527 | siglongjmp(jmpbuf, 1); | |
528 | } | |
529 | ||
530 | static void do_multicpu_tests(void) | |
531 | { | |
532 | cpu_set_t cpuset; | |
533 | pthread_t thread; | |
534 | int failures = 0, iters = 5, i; | |
535 | unsigned short orig_ss; | |
536 | ||
537 | CPU_ZERO(&cpuset); | |
538 | CPU_SET(1, &cpuset); | |
539 | if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) { | |
540 | printf("[SKIP]\tCannot set affinity to CPU 1\n"); | |
541 | return; | |
542 | } | |
543 | ||
544 | CPU_ZERO(&cpuset); | |
545 | CPU_SET(0, &cpuset); | |
546 | if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0) { | |
547 | printf("[SKIP]\tCannot set affinity to CPU 0\n"); | |
548 | return; | |
549 | } | |
550 | ||
551 | sethandler(SIGSEGV, sigsegv, 0); | |
552 | #ifdef __i386__ | |
553 | /* True 32-bit kernels send SIGILL instead of SIGSEGV on IRET faults. */ | |
554 | sethandler(SIGILL, sigsegv, 0); | |
555 | #endif | |
556 | ||
557 | printf("[RUN]\tCross-CPU LDT invalidation\n"); | |
558 | ||
559 | if (pthread_create(&thread, 0, threadproc, 0) != 0) | |
560 | err(1, "pthread_create"); | |
561 | ||
562 | asm volatile ("mov %%ss, %0" : "=rm" (orig_ss)); | |
563 | ||
564 | for (i = 0; i < 5; i++) { | |
565 | if (sigsetjmp(jmpbuf, 1) != 0) | |
566 | continue; | |
567 | ||
568 | /* Make sure the thread is ready after the last test. */ | |
569 | while (ftx != 0) | |
570 | ; | |
571 | ||
572 | struct user_desc desc = { | |
573 | .entry_number = 0, | |
574 | .base_addr = 0, | |
575 | .limit = 0xfffff, | |
576 | .seg_32bit = 1, | |
577 | .contents = 0, /* Data */ | |
578 | .read_exec_only = 0, | |
579 | .limit_in_pages = 1, | |
580 | .seg_not_present = 0, | |
581 | .useable = 0 | |
582 | }; | |
583 | ||
584 | if (safe_modify_ldt(0x11, &desc, sizeof(desc)) != 0) { | |
585 | if (errno != ENOSYS) | |
586 | err(1, "modify_ldt"); | |
587 | printf("[SKIP]\tmodify_ldt unavailable\n"); | |
588 | break; | |
589 | } | |
590 | ||
591 | /* Arm the thread. */ | |
592 | ftx = 1; | |
593 | syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0); | |
594 | ||
595 | asm volatile ("mov %0, %%ss" : : "r" (0x7)); | |
596 | ||
597 | /* Go! */ | |
598 | ftx = 2; | |
599 | ||
600 | while (ftx != 0) | |
601 | ; | |
602 | ||
603 | /* | |
604 | * On success, modify_ldt will segfault us synchronously, | |
605 | * and we'll escape via siglongjmp. | |
606 | */ | |
607 | ||
608 | failures++; | |
609 | asm volatile ("mov %0, %%ss" : : "rm" (orig_ss)); | |
610 | }; | |
611 | ||
612 | ftx = 100; /* Kill the thread. */ | |
613 | syscall(SYS_futex, &ftx, FUTEX_WAKE, 0, NULL, NULL, 0); | |
614 | ||
615 | if (pthread_join(thread, NULL) != 0) | |
616 | err(1, "pthread_join"); | |
617 | ||
618 | if (failures) { | |
619 | printf("[FAIL]\t%d of %d iterations failed\n", failures, iters); | |
620 | nerrs++; | |
621 | } else { | |
622 | printf("[OK]\tAll %d iterations succeeded\n", iters); | |
623 | } | |
624 | } | |
625 | ||
626 | static int finish_exec_test(void) | |
627 | { | |
628 | /* | |
a4828f81 TG |
629 | * Older kernel versions did inherit the LDT on exec() which is |
630 | * wrong because exec() starts from a clean state. | |
014dc90b | 631 | */ |
a4828f81 | 632 | check_invalid_segment(0, 1); |
014dc90b AL |
633 | |
634 | return nerrs ? 1 : 0; | |
635 | } | |
636 | ||
637 | static void do_exec_test(void) | |
638 | { | |
639 | printf("[RUN]\tTest exec\n"); | |
640 | ||
641 | struct user_desc desc = { | |
642 | .entry_number = 0, | |
643 | .base_addr = 0, | |
644 | .limit = 42, | |
645 | .seg_32bit = 1, | |
646 | .contents = 2, /* Code, not conforming */ | |
647 | .read_exec_only = 0, | |
648 | .limit_in_pages = 0, | |
649 | .seg_not_present = 0, | |
650 | .useable = 0 | |
651 | }; | |
652 | install_valid(&desc, AR_DPL3 | AR_TYPE_XRCODE | AR_S | AR_P | AR_DB); | |
653 | ||
654 | pid_t child = fork(); | |
655 | if (child == 0) { | |
656 | execl("/proc/self/exe", "ldt_gdt_test_exec", NULL); | |
657 | printf("[FAIL]\tCould not exec self\n"); | |
658 | exit(1); /* exec failed */ | |
659 | } else { | |
660 | int status; | |
661 | if (waitpid(child, &status, 0) != child || | |
662 | !WIFEXITED(status)) { | |
663 | printf("[FAIL]\tChild died\n"); | |
664 | nerrs++; | |
665 | } else if (WEXITSTATUS(status) != 0) { | |
666 | printf("[FAIL]\tChild failed\n"); | |
667 | nerrs++; | |
668 | } else { | |
669 | printf("[OK]\tChild succeeded\n"); | |
670 | } | |
671 | } | |
672 | } | |
673 | ||
d63f4b52 AL |
674 | static void setup_counter_page(void) |
675 | { | |
676 | unsigned int *page = mmap(NULL, 4096, PROT_READ | PROT_WRITE, | |
677 | MAP_ANONYMOUS | MAP_PRIVATE | MAP_32BIT, -1, 0); | |
678 | if (page == MAP_FAILED) | |
679 | err(1, "mmap"); | |
680 | ||
681 | for (int i = 0; i < 1024; i++) | |
682 | page[i] = i; | |
683 | counter_page = page; | |
684 | } | |
685 | ||
686 | static int invoke_set_thread_area(void) | |
687 | { | |
688 | int ret; | |
689 | asm volatile ("int $0x80" | |
690 | : "=a" (ret), "+m" (low_user_desc) : | |
691 | "a" (243), "b" (low_user_desc) | |
2a4d0c62 | 692 | : INT80_CLOBBERS); |
d63f4b52 AL |
693 | return ret; |
694 | } | |
695 | ||
696 | static void setup_low_user_desc(void) | |
697 | { | |
698 | low_user_desc = mmap(NULL, 2 * sizeof(struct user_desc), | |
699 | PROT_READ | PROT_WRITE, | |
700 | MAP_ANONYMOUS | MAP_PRIVATE | MAP_32BIT, -1, 0); | |
701 | if (low_user_desc == MAP_FAILED) | |
702 | err(1, "mmap"); | |
703 | ||
704 | low_user_desc->entry_number = -1; | |
705 | low_user_desc->base_addr = (unsigned long)&counter_page[1]; | |
706 | low_user_desc->limit = 0xfffff; | |
707 | low_user_desc->seg_32bit = 1; | |
708 | low_user_desc->contents = 0; /* Data, grow-up*/ | |
709 | low_user_desc->read_exec_only = 0; | |
710 | low_user_desc->limit_in_pages = 1; | |
711 | low_user_desc->seg_not_present = 0; | |
712 | low_user_desc->useable = 0; | |
713 | ||
714 | if (invoke_set_thread_area() == 0) { | |
715 | gdt_entry_num = low_user_desc->entry_number; | |
716 | printf("[NOTE]\tset_thread_area is available; will use GDT index %d\n", gdt_entry_num); | |
717 | } else { | |
718 | printf("[NOTE]\tset_thread_area is unavailable\n"); | |
719 | } | |
720 | ||
721 | low_user_desc_clear = low_user_desc + 1; | |
722 | low_user_desc_clear->entry_number = gdt_entry_num; | |
723 | low_user_desc_clear->read_exec_only = 1; | |
724 | low_user_desc_clear->seg_not_present = 1; | |
725 | } | |
726 | ||
727 | static void test_gdt_invalidation(void) | |
728 | { | |
729 | if (!gdt_entry_num) | |
730 | return; /* 64-bit only system -- we can't use set_thread_area */ | |
731 | ||
732 | unsigned short prev_sel; | |
733 | unsigned short sel; | |
734 | unsigned int eax; | |
735 | const char *result; | |
736 | #ifdef __x86_64__ | |
737 | unsigned long saved_base; | |
738 | unsigned long new_base; | |
739 | #endif | |
740 | ||
741 | /* Test DS */ | |
742 | invoke_set_thread_area(); | |
743 | eax = 243; | |
744 | sel = (gdt_entry_num << 3) | 3; | |
745 | asm volatile ("movw %%ds, %[prev_sel]\n\t" | |
746 | "movw %[sel], %%ds\n\t" | |
747 | #ifdef __i386__ | |
748 | "pushl %%ebx\n\t" | |
749 | #endif | |
750 | "movl %[arg1], %%ebx\n\t" | |
751 | "int $0x80\n\t" /* Should invalidate ds */ | |
752 | #ifdef __i386__ | |
753 | "popl %%ebx\n\t" | |
754 | #endif | |
755 | "movw %%ds, %[sel]\n\t" | |
756 | "movw %[prev_sel], %%ds" | |
757 | : [prev_sel] "=&r" (prev_sel), [sel] "+r" (sel), | |
758 | "+a" (eax) | |
759 | : "m" (low_user_desc_clear), | |
760 | [arg1] "r" ((unsigned int)(unsigned long)low_user_desc_clear) | |
2a4d0c62 | 761 | : INT80_CLOBBERS); |
d63f4b52 AL |
762 | |
763 | if (sel != 0) { | |
764 | result = "FAIL"; | |
765 | nerrs++; | |
766 | } else { | |
767 | result = "OK"; | |
768 | } | |
769 | printf("[%s]\tInvalidate DS with set_thread_area: new DS = 0x%hx\n", | |
770 | result, sel); | |
771 | ||
772 | /* Test ES */ | |
773 | invoke_set_thread_area(); | |
774 | eax = 243; | |
775 | sel = (gdt_entry_num << 3) | 3; | |
776 | asm volatile ("movw %%es, %[prev_sel]\n\t" | |
777 | "movw %[sel], %%es\n\t" | |
778 | #ifdef __i386__ | |
779 | "pushl %%ebx\n\t" | |
780 | #endif | |
781 | "movl %[arg1], %%ebx\n\t" | |
782 | "int $0x80\n\t" /* Should invalidate es */ | |
783 | #ifdef __i386__ | |
784 | "popl %%ebx\n\t" | |
785 | #endif | |
786 | "movw %%es, %[sel]\n\t" | |
787 | "movw %[prev_sel], %%es" | |
788 | : [prev_sel] "=&r" (prev_sel), [sel] "+r" (sel), | |
789 | "+a" (eax) | |
790 | : "m" (low_user_desc_clear), | |
791 | [arg1] "r" ((unsigned int)(unsigned long)low_user_desc_clear) | |
2a4d0c62 | 792 | : INT80_CLOBBERS); |
d63f4b52 AL |
793 | |
794 | if (sel != 0) { | |
795 | result = "FAIL"; | |
796 | nerrs++; | |
797 | } else { | |
798 | result = "OK"; | |
799 | } | |
800 | printf("[%s]\tInvalidate ES with set_thread_area: new ES = 0x%hx\n", | |
801 | result, sel); | |
802 | ||
803 | /* Test FS */ | |
804 | invoke_set_thread_area(); | |
805 | eax = 243; | |
806 | sel = (gdt_entry_num << 3) | 3; | |
807 | #ifdef __x86_64__ | |
808 | syscall(SYS_arch_prctl, ARCH_GET_FS, &saved_base); | |
809 | #endif | |
810 | asm volatile ("movw %%fs, %[prev_sel]\n\t" | |
811 | "movw %[sel], %%fs\n\t" | |
812 | #ifdef __i386__ | |
813 | "pushl %%ebx\n\t" | |
814 | #endif | |
815 | "movl %[arg1], %%ebx\n\t" | |
816 | "int $0x80\n\t" /* Should invalidate fs */ | |
817 | #ifdef __i386__ | |
818 | "popl %%ebx\n\t" | |
819 | #endif | |
820 | "movw %%fs, %[sel]\n\t" | |
821 | : [prev_sel] "=&r" (prev_sel), [sel] "+r" (sel), | |
822 | "+a" (eax) | |
823 | : "m" (low_user_desc_clear), | |
824 | [arg1] "r" ((unsigned int)(unsigned long)low_user_desc_clear) | |
2a4d0c62 | 825 | : INT80_CLOBBERS); |
d63f4b52 AL |
826 | |
827 | #ifdef __x86_64__ | |
828 | syscall(SYS_arch_prctl, ARCH_GET_FS, &new_base); | |
829 | #endif | |
830 | ||
831 | /* Restore FS/BASE for glibc */ | |
832 | asm volatile ("movw %[prev_sel], %%fs" : : [prev_sel] "rm" (prev_sel)); | |
833 | #ifdef __x86_64__ | |
834 | if (saved_base) | |
835 | syscall(SYS_arch_prctl, ARCH_SET_FS, saved_base); | |
836 | #endif | |
837 | ||
838 | if (sel != 0) { | |
839 | result = "FAIL"; | |
840 | nerrs++; | |
841 | } else { | |
842 | result = "OK"; | |
843 | } | |
844 | printf("[%s]\tInvalidate FS with set_thread_area: new FS = 0x%hx\n", | |
845 | result, sel); | |
846 | ||
847 | #ifdef __x86_64__ | |
848 | if (sel == 0 && new_base != 0) { | |
849 | nerrs++; | |
850 | printf("[FAIL]\tNew FSBASE was 0x%lx\n", new_base); | |
851 | } else { | |
852 | printf("[OK]\tNew FSBASE was zero\n"); | |
853 | } | |
854 | #endif | |
855 | ||
856 | /* Test GS */ | |
857 | invoke_set_thread_area(); | |
858 | eax = 243; | |
859 | sel = (gdt_entry_num << 3) | 3; | |
860 | #ifdef __x86_64__ | |
861 | syscall(SYS_arch_prctl, ARCH_GET_GS, &saved_base); | |
862 | #endif | |
863 | asm volatile ("movw %%gs, %[prev_sel]\n\t" | |
864 | "movw %[sel], %%gs\n\t" | |
865 | #ifdef __i386__ | |
866 | "pushl %%ebx\n\t" | |
867 | #endif | |
868 | "movl %[arg1], %%ebx\n\t" | |
869 | "int $0x80\n\t" /* Should invalidate gs */ | |
870 | #ifdef __i386__ | |
871 | "popl %%ebx\n\t" | |
872 | #endif | |
873 | "movw %%gs, %[sel]\n\t" | |
874 | : [prev_sel] "=&r" (prev_sel), [sel] "+r" (sel), | |
875 | "+a" (eax) | |
876 | : "m" (low_user_desc_clear), | |
877 | [arg1] "r" ((unsigned int)(unsigned long)low_user_desc_clear) | |
2a4d0c62 | 878 | : INT80_CLOBBERS); |
d63f4b52 AL |
879 | |
880 | #ifdef __x86_64__ | |
881 | syscall(SYS_arch_prctl, ARCH_GET_GS, &new_base); | |
882 | #endif | |
883 | ||
884 | /* Restore GS/BASE for glibc */ | |
885 | asm volatile ("movw %[prev_sel], %%gs" : : [prev_sel] "rm" (prev_sel)); | |
886 | #ifdef __x86_64__ | |
887 | if (saved_base) | |
888 | syscall(SYS_arch_prctl, ARCH_SET_GS, saved_base); | |
889 | #endif | |
890 | ||
891 | if (sel != 0) { | |
892 | result = "FAIL"; | |
893 | nerrs++; | |
894 | } else { | |
895 | result = "OK"; | |
896 | } | |
897 | printf("[%s]\tInvalidate GS with set_thread_area: new GS = 0x%hx\n", | |
898 | result, sel); | |
899 | ||
900 | #ifdef __x86_64__ | |
901 | if (sel == 0 && new_base != 0) { | |
902 | nerrs++; | |
903 | printf("[FAIL]\tNew GSBASE was 0x%lx\n", new_base); | |
904 | } else { | |
905 | printf("[OK]\tNew GSBASE was zero\n"); | |
906 | } | |
907 | #endif | |
908 | } | |
909 | ||
014dc90b AL |
910 | int main(int argc, char **argv) |
911 | { | |
912 | if (argc == 1 && !strcmp(argv[0], "ldt_gdt_test_exec")) | |
913 | return finish_exec_test(); | |
914 | ||
d63f4b52 AL |
915 | setup_counter_page(); |
916 | setup_low_user_desc(); | |
917 | ||
014dc90b AL |
918 | do_simple_tests(); |
919 | ||
920 | do_multicpu_tests(); | |
921 | ||
922 | do_exec_test(); | |
923 | ||
d63f4b52 AL |
924 | test_gdt_invalidation(); |
925 | ||
014dc90b AL |
926 | return nerrs ? 1 : 0; |
927 | } |