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5
6#include <stdio.h>
7#include <stdlib.h>
8#include <stdarg.h>
9#include <unistd.h>
10#include <errno.h>
11#include <fcntl.h>
12#include <sched.h>
13#include <signal.h>
14#include <string.h>
15#include <sys/mman.h>
16#include <sys/ptrace.h>
17#include <sys/stat.h>
18#include <sys/wait.h>
19#include <asm/unistd.h>
20#include "init.h"
21#include "kern_constants.h"
22#include "os.h"
23#include "mem_user.h"
24#include "ptrace_user.h"
25#include "registers.h"
26#include "skas.h"
27#include "skas_ptrace.h"
28
29static void ptrace_child(void)
30{
31 int ret;
32
33 int pid = os_getpid(), ppid = getppid();
34 int sc_result;
35
36 if (change_sig(SIGWINCH, 0) < 0 ||
37 ptrace(PTRACE_TRACEME, 0, 0, 0) < 0) {
38 perror("ptrace");
39 kill(pid, SIGKILL);
40 }
41 kill(pid, SIGSTOP);
42
43
44
45
46
47 sc_result = os_getpid();
48
49 if (sc_result == pid)
50
51 ret = 1;
52 else if (sc_result == ppid)
53
54
55
56
57 ret = 0;
58 else
59
60
61
62
63 ret = 2;
64
65 exit(ret);
66}
67
68static void fatal_perror(const char *str)
69{
70 perror(str);
71 exit(1);
72}
73
74static void fatal(char *fmt, ...)
75{
76 va_list list;
77
78 va_start(list, fmt);
79 vfprintf(stderr, fmt, list);
80 va_end(list);
81
82 exit(1);
83}
84
85static void non_fatal(char *fmt, ...)
86{
87 va_list list;
88
89 va_start(list, fmt);
90 vfprintf(stderr, fmt, list);
91 va_end(list);
92}
93
94static int start_ptraced_child(void)
95{
96 int pid, n, status;
97
98 pid = fork();
99 if (pid == 0)
100 ptrace_child();
101 else if (pid < 0)
102 fatal_perror("start_ptraced_child : fork failed");
103
104 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
105 if (n < 0)
106 fatal_perror("check_ptrace : waitpid failed");
107 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGSTOP))
108 fatal("check_ptrace : expected SIGSTOP, got status = %d",
109 status);
110
111 return pid;
112}
113
114
115
116
117
118
119
120static int stop_ptraced_child(int pid, int exitcode, int mustexit)
121{
122 int status, n, ret = 0;
123
124 if (ptrace(PTRACE_CONT, pid, 0, 0) < 0) {
125 perror("stop_ptraced_child : ptrace failed");
126 return -1;
127 }
128 CATCH_EINTR(n = waitpid(pid, &status, 0));
129 if (!WIFEXITED(status) || (WEXITSTATUS(status) != exitcode)) {
130 int exit_with = WEXITSTATUS(status);
131 if (exit_with == 2)
132 non_fatal("check_ptrace : child exited with status 2. "
133 "\nDisabling SYSEMU support.\n");
134 non_fatal("check_ptrace : child exited with exitcode %d, while "
135 "expecting %d; status 0x%x\n", exit_with,
136 exitcode, status);
137 if (mustexit)
138 exit(1);
139 ret = -1;
140 }
141
142 return ret;
143}
144
145
146int ptrace_faultinfo;
147static int disable_ptrace_faultinfo;
148
149int ptrace_ldt;
150static int disable_ptrace_ldt;
151
152int proc_mm;
153static int disable_proc_mm;
154
155int have_switch_mm;
156static int disable_switch_mm;
157
158int skas_needs_stub;
159
160static int __init skas0_cmd_param(char *str, int* add)
161{
162 disable_ptrace_faultinfo = 1;
163 disable_ptrace_ldt = 1;
164 disable_proc_mm = 1;
165 disable_switch_mm = 1;
166
167 return 0;
168}
169
170
171
172static int __init mode_skas0_cmd_param(char *str, int* add)
173 __attribute__((alias("skas0_cmd_param")));
174
175__uml_setup("skas0", skas0_cmd_param,
176"skas0\n"
177" Disables SKAS3 and SKAS4 usage, so that SKAS0 is used\n\n");
178
179__uml_setup("mode=skas0", mode_skas0_cmd_param,
180"mode=skas0\n"
181" Disables SKAS3 and SKAS4 usage, so that SKAS0 is used.\n\n");
182
183
184static int force_sysemu_disabled = 0;
185
186static int __init nosysemu_cmd_param(char *str, int* add)
187{
188 force_sysemu_disabled = 1;
189 return 0;
190}
191
192__uml_setup("nosysemu", nosysemu_cmd_param,
193"nosysemu\n"
194" Turns off syscall emulation patch for ptrace (SYSEMU) on.\n"
195" SYSEMU is a performance-patch introduced by Laurent Vivier. It changes\n"
196" behaviour of ptrace() and helps reducing host context switch rate.\n"
197" To make it working, you need a kernel patch for your host, too.\n"
198" See http://perso.wanadoo.fr/laurent.vivier/UML/ for further \n"
199" information.\n\n");
200
201static void __init check_sysemu(void)
202{
203 unsigned long regs[MAX_REG_NR];
204 int pid, n, status, count=0;
205
206 non_fatal("Checking syscall emulation patch for ptrace...");
207 sysemu_supported = 0;
208 pid = start_ptraced_child();
209
210 if (ptrace(PTRACE_SYSEMU, pid, 0, 0) < 0)
211 goto fail;
212
213 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
214 if (n < 0)
215 fatal_perror("check_sysemu : wait failed");
216 if (!WIFSTOPPED(status) || (WSTOPSIG(status) != SIGTRAP))
217 fatal("check_sysemu : expected SIGTRAP, got status = %d\n",
218 status);
219
220 if (ptrace(PTRACE_GETREGS, pid, 0, regs) < 0)
221 fatal_perror("check_sysemu : PTRACE_GETREGS failed");
222 if (PT_SYSCALL_NR(regs) != __NR_getpid) {
223 non_fatal("check_sysemu got system call number %d, "
224 "expected %d...", PT_SYSCALL_NR(regs), __NR_getpid);
225 goto fail;
226 }
227
228 n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET, os_getpid());
229 if (n < 0) {
230 non_fatal("check_sysemu : failed to modify system call "
231 "return");
232 goto fail;
233 }
234
235 if (stop_ptraced_child(pid, 0, 0) < 0)
236 goto fail_stopped;
237
238 sysemu_supported = 1;
239 non_fatal("OK\n");
240 set_using_sysemu(!force_sysemu_disabled);
241
242 non_fatal("Checking advanced syscall emulation patch for ptrace...");
243 pid = start_ptraced_child();
244
245 if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
246 (void *) PTRACE_O_TRACESYSGOOD) < 0))
247 fatal_perror("check_sysemu: PTRACE_OLDSETOPTIONS failed");
248
249 while (1) {
250 count++;
251 if (ptrace(PTRACE_SYSEMU_SINGLESTEP, pid, 0, 0) < 0)
252 goto fail;
253 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
254 if (n < 0)
255 fatal_perror("check_sysemu: wait failed");
256
257 if (WIFSTOPPED(status) &&
258 (WSTOPSIG(status) == (SIGTRAP|0x80))) {
259 if (!count) {
260 non_fatal("check_sysemu: SYSEMU_SINGLESTEP "
261 "doesn't singlestep");
262 goto fail;
263 }
264 n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_RET_OFFSET,
265 os_getpid());
266 if (n < 0)
267 fatal_perror("check_sysemu : failed to modify "
268 "system call return");
269 break;
270 }
271 else if (WIFSTOPPED(status) && (WSTOPSIG(status) == SIGTRAP))
272 count++;
273 else {
274 non_fatal("check_sysemu: expected SIGTRAP or "
275 "(SIGTRAP | 0x80), got status = %d\n",
276 status);
277 goto fail;
278 }
279 }
280 if (stop_ptraced_child(pid, 0, 0) < 0)
281 goto fail_stopped;
282
283 sysemu_supported = 2;
284 non_fatal("OK\n");
285
286 if (!force_sysemu_disabled)
287 set_using_sysemu(sysemu_supported);
288 return;
289
290fail:
291 stop_ptraced_child(pid, 1, 0);
292fail_stopped:
293 non_fatal("missing\n");
294}
295
296static void __init check_ptrace(void)
297{
298 int pid, syscall, n, status;
299
300 non_fatal("Checking that ptrace can change system call numbers...");
301 pid = start_ptraced_child();
302
303 if ((ptrace(PTRACE_OLDSETOPTIONS, pid, 0,
304 (void *) PTRACE_O_TRACESYSGOOD) < 0))
305 fatal_perror("check_ptrace: PTRACE_OLDSETOPTIONS failed");
306
307 while (1) {
308 if (ptrace(PTRACE_SYSCALL, pid, 0, 0) < 0)
309 fatal_perror("check_ptrace : ptrace failed");
310
311 CATCH_EINTR(n = waitpid(pid, &status, WUNTRACED));
312 if (n < 0)
313 fatal_perror("check_ptrace : wait failed");
314
315 if (!WIFSTOPPED(status) ||
316 (WSTOPSIG(status) != (SIGTRAP | 0x80)))
317 fatal("check_ptrace : expected (SIGTRAP|0x80), "
318 "got status = %d", status);
319
320 syscall = ptrace(PTRACE_PEEKUSR, pid, PT_SYSCALL_NR_OFFSET,
321 0);
322 if (syscall == __NR_getpid) {
323 n = ptrace(PTRACE_POKEUSR, pid, PT_SYSCALL_NR_OFFSET,
324 __NR_getppid);
325 if (n < 0)
326 fatal_perror("check_ptrace : failed to modify "
327 "system call");
328 break;
329 }
330 }
331 stop_ptraced_child(pid, 0, 1);
332 non_fatal("OK\n");
333 check_sysemu();
334}
335
336extern void check_tmpexec(void);
337
338static void __init check_coredump_limit(void)
339{
340 struct rlimit lim;
341 int err = getrlimit(RLIMIT_CORE, &lim);
342
343 if (err) {
344 perror("Getting core dump limit");
345 return;
346 }
347
348 printf("Core dump limits :\n\tsoft - ");
349 if (lim.rlim_cur == RLIM_INFINITY)
350 printf("NONE\n");
351 else printf("%lu\n", lim.rlim_cur);
352
353 printf("\thard - ");
354 if (lim.rlim_max == RLIM_INFINITY)
355 printf("NONE\n");
356 else printf("%lu\n", lim.rlim_max);
357}
358
359void __init os_early_checks(void)
360{
361 int pid;
362
363
364 check_coredump_limit();
365
366 check_ptrace();
367
368
369
370
371 check_tmpexec();
372
373 pid = start_ptraced_child();
374 if (init_registers(pid))
375 fatal("Failed to initialize default registers");
376 stop_ptraced_child(pid, 1, 1);
377}
378
379static int __init noprocmm_cmd_param(char *str, int* add)
380{
381 disable_proc_mm = 1;
382 return 0;
383}
384
385__uml_setup("noprocmm", noprocmm_cmd_param,
386"noprocmm\n"
387" Turns off usage of /proc/mm, even if host supports it.\n"
388" To support /proc/mm, the host needs to be patched using\n"
389" the current skas3 patch.\n\n");
390
391static int __init noptracefaultinfo_cmd_param(char *str, int* add)
392{
393 disable_ptrace_faultinfo = 1;
394 return 0;
395}
396
397__uml_setup("noptracefaultinfo", noptracefaultinfo_cmd_param,
398"noptracefaultinfo\n"
399" Turns off usage of PTRACE_FAULTINFO, even if host supports\n"
400" it. To support PTRACE_FAULTINFO, the host needs to be patched\n"
401" using the current skas3 patch.\n\n");
402
403static int __init noptraceldt_cmd_param(char *str, int* add)
404{
405 disable_ptrace_ldt = 1;
406 return 0;
407}
408
409__uml_setup("noptraceldt", noptraceldt_cmd_param,
410"noptraceldt\n"
411" Turns off usage of PTRACE_LDT, even if host supports it.\n"
412" To support PTRACE_LDT, the host needs to be patched using\n"
413" the current skas3 patch.\n\n");
414
415static inline void check_skas3_ptrace_faultinfo(void)
416{
417 struct ptrace_faultinfo fi;
418 int pid, n;
419
420 non_fatal(" - PTRACE_FAULTINFO...");
421 pid = start_ptraced_child();
422
423 n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi);
424 if (n < 0) {
425 if (errno == EIO)
426 non_fatal("not found\n");
427 else
428 perror("not found");
429 } else if (disable_ptrace_faultinfo)
430 non_fatal("found but disabled on command line\n");
431 else {
432 ptrace_faultinfo = 1;
433 non_fatal("found\n");
434 }
435
436 stop_ptraced_child(pid, 1, 1);
437}
438
439static inline void check_skas3_ptrace_ldt(void)
440{
441#ifdef PTRACE_LDT
442 int pid, n;
443 unsigned char ldtbuf[40];
444 struct ptrace_ldt ldt_op = (struct ptrace_ldt) {
445 .func = 2,
446 .ptr = ldtbuf,
447 .bytecount = sizeof(ldtbuf)};
448
449 non_fatal(" - PTRACE_LDT...");
450 pid = start_ptraced_child();
451
452 n = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op);
453 if (n < 0) {
454 if (errno == EIO)
455 non_fatal("not found\n");
456 else
457 perror("not found");
458 } else if (disable_ptrace_ldt)
459 non_fatal("found, but use is disabled\n");
460 else {
461 ptrace_ldt = 1;
462 non_fatal("found\n");
463 }
464
465 stop_ptraced_child(pid, 1, 1);
466#endif
467}
468
469static inline void check_skas3_proc_mm(void)
470{
471 non_fatal(" - /proc/mm...");
472 if (access("/proc/mm", W_OK) < 0)
473 perror("not found");
474 else if (disable_proc_mm)
475 non_fatal("found but disabled on command line\n");
476 else {
477 proc_mm = 1;
478 non_fatal("found\n");
479 }
480}
481
482void can_do_skas(void)
483{
484 non_fatal("Checking for the skas3 patch in the host:\n");
485
486 check_skas3_proc_mm();
487 check_skas3_ptrace_faultinfo();
488 check_skas3_ptrace_ldt();
489
490 if (!proc_mm || !ptrace_faultinfo || !ptrace_ldt)
491 skas_needs_stub = 1;
492}
493
494int __init parse_iomem(char *str, int *add)
495{
496 struct iomem_region *new;
497 struct stat64 buf;
498 char *file, *driver;
499 int fd, size;
500
501 driver = str;
502 file = strchr(str,',');
503 if (file == NULL) {
504 fprintf(stderr, "parse_iomem : failed to parse iomem\n");
505 goto out;
506 }
507 *file = '\0';
508 file++;
509 fd = open(file, O_RDWR, 0);
510 if (fd < 0) {
511 perror("parse_iomem - Couldn't open io file");
512 goto out;
513 }
514
515 if (fstat64(fd, &buf) < 0) {
516 perror("parse_iomem - cannot stat_fd file");
517 goto out_close;
518 }
519
520 new = malloc(sizeof(*new));
521 if (new == NULL) {
522 perror("Couldn't allocate iomem_region struct");
523 goto out_close;
524 }
525
526 size = (buf.st_size + UM_KERN_PAGE_SIZE) & ~(UM_KERN_PAGE_SIZE - 1);
527
528 *new = ((struct iomem_region) { .next = iomem_regions,
529 .driver = driver,
530 .fd = fd,
531 .size = size,
532 .phys = 0,
533 .virt = 0 });
534 iomem_regions = new;
535 iomem_size += new->size + UM_KERN_PAGE_SIZE;
536
537 return 0;
538 out_close:
539 close(fd);
540 out:
541 return 1;
542}
543
