blob: 7596e1e94cde858df0ba7ea0907f9b86d1f4132e [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * linux/fs/binfmt_aout.c
3 *
4 * Copyright (C) 1991, 1992, 1996 Linus Torvalds
5 */
6
7#include <linux/module.h>
8
9#include <linux/time.h>
10#include <linux/kernel.h>
11#include <linux/mm.h>
12#include <linux/mman.h>
13#include <linux/a.out.h>
14#include <linux/errno.h>
15#include <linux/signal.h>
16#include <linux/string.h>
17#include <linux/fs.h>
18#include <linux/file.h>
19#include <linux/stat.h>
20#include <linux/fcntl.h>
21#include <linux/ptrace.h>
22#include <linux/user.h>
23#include <linux/slab.h>
24#include <linux/binfmts.h>
25#include <linux/personality.h>
26#include <linux/init.h>
27
28#include <asm/system.h>
29#include <asm/uaccess.h>
30#include <asm/cacheflush.h>
31
32static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
33static int load_aout_library(struct file*);
Neil Horman7dc0b222007-10-16 23:26:34 -070034static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit);
Linus Torvalds1da177e2005-04-16 15:20:36 -070035
Linus Torvalds1da177e2005-04-16 15:20:36 -070036static struct linux_binfmt aout_format = {
37 .module = THIS_MODULE,
38 .load_binary = load_aout_binary,
39 .load_shlib = load_aout_library,
40 .core_dump = aout_core_dump,
41 .min_coredump = PAGE_SIZE
42};
43
44#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
45
46static int set_brk(unsigned long start, unsigned long end)
47{
48 start = PAGE_ALIGN(start);
49 end = PAGE_ALIGN(end);
50 if (end > start) {
51 unsigned long addr;
52 down_write(&current->mm->mmap_sem);
53 addr = do_brk(start, end - start);
54 up_write(&current->mm->mmap_sem);
55 if (BAD_ADDR(addr))
56 return addr;
57 }
58 return 0;
59}
60
61/*
62 * These are the only things you should do on a core-file: use only these
63 * macros to write out all the necessary info.
64 */
65
66static int dump_write(struct file *file, const void *addr, int nr)
67{
68 return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
69}
70
71#define DUMP_WRITE(addr, nr) \
72 if (!dump_write(file, (void *)(addr), (nr))) \
73 goto end_coredump;
74
75#define DUMP_SEEK(offset) \
76if (file->f_op->llseek) { \
77 if (file->f_op->llseek(file,(offset),0) != (offset)) \
78 goto end_coredump; \
79} else file->f_pos = (offset)
80
81/*
82 * Routine writes a core dump image in the current directory.
83 * Currently only a stub-function.
84 *
85 * Note that setuid/setgid files won't make a core-dump if the uid/gid
86 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
87 * field, which also makes sure the core-dumps won't be recursive if the
88 * dumping of the process results in another error..
89 */
90
Neil Horman7dc0b222007-10-16 23:26:34 -070091static int aout_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -070092{
93 mm_segment_t fs;
94 int has_dumped = 0;
95 unsigned long dump_start, dump_size;
96 struct user dump;
97#if defined(__alpha__)
98# define START_DATA(u) (u.start_data)
99#elif defined(__arm__)
100# define START_DATA(u) ((u.u_tsize << PAGE_SHIFT) + u.start_code)
101#elif defined(__sparc__)
102# define START_DATA(u) (u.u_tsize)
103#elif defined(__i386__) || defined(__mc68000__) || defined(__arch_um__)
104# define START_DATA(u) (u.u_tsize << PAGE_SHIFT)
105#endif
106#ifdef __sparc__
107# define START_STACK(u) ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1))
108#else
109# define START_STACK(u) (u.start_stack)
110#endif
111
112 fs = get_fs();
113 set_fs(KERNEL_DS);
114 has_dumped = 1;
115 current->flags |= PF_DUMPCORE;
116 strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm));
117#ifndef __sparc__
118 dump.u_ar0 = (void *)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
119#endif
120 dump.signal = signr;
121 dump_thread(regs, &dump);
122
123/* If the size of the dump file exceeds the rlimit, then see what would happen
124 if we wrote the stack, but not the data area. */
125#ifdef __sparc__
Neil Horman7dc0b222007-10-16 23:26:34 -0700126 if ((dump.u_dsize + dump.u_ssize) > limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700127 dump.u_dsize = 0;
128#else
Neil Horman7dc0b222007-10-16 23:26:34 -0700129 if ((dump.u_dsize + dump.u_ssize+1) * PAGE_SIZE > limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700130 dump.u_dsize = 0;
131#endif
132
133/* Make sure we have enough room to write the stack and data areas. */
134#ifdef __sparc__
Neil Horman7dc0b222007-10-16 23:26:34 -0700135 if (dump.u_ssize > limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136 dump.u_ssize = 0;
137#else
Neil Horman7dc0b222007-10-16 23:26:34 -0700138 if ((dump.u_ssize + 1) * PAGE_SIZE > limit)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139 dump.u_ssize = 0;
140#endif
141
142/* make sure we actually have a data and stack area to dump */
143 set_fs(USER_DS);
144#ifdef __sparc__
145 if (!access_ok(VERIFY_READ, (void __user *)START_DATA(dump), dump.u_dsize))
146 dump.u_dsize = 0;
147 if (!access_ok(VERIFY_READ, (void __user *)START_STACK(dump), dump.u_ssize))
148 dump.u_ssize = 0;
149#else
150 if (!access_ok(VERIFY_READ, (void __user *)START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
151 dump.u_dsize = 0;
152 if (!access_ok(VERIFY_READ, (void __user *)START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
153 dump.u_ssize = 0;
154#endif
155
156 set_fs(KERNEL_DS);
157/* struct user */
158 DUMP_WRITE(&dump,sizeof(dump));
159/* Now dump all of the user data. Include malloced stuff as well */
160#ifndef __sparc__
161 DUMP_SEEK(PAGE_SIZE);
162#endif
163/* now we start writing out the user space info */
164 set_fs(USER_DS);
165/* Dump the data area */
166 if (dump.u_dsize != 0) {
167 dump_start = START_DATA(dump);
168#ifdef __sparc__
169 dump_size = dump.u_dsize;
170#else
171 dump_size = dump.u_dsize << PAGE_SHIFT;
172#endif
173 DUMP_WRITE(dump_start,dump_size);
174 }
175/* Now prepare to dump the stack area */
176 if (dump.u_ssize != 0) {
177 dump_start = START_STACK(dump);
178#ifdef __sparc__
179 dump_size = dump.u_ssize;
180#else
181 dump_size = dump.u_ssize << PAGE_SHIFT;
182#endif
183 DUMP_WRITE(dump_start,dump_size);
184 }
185/* Finally dump the task struct. Not be used by gdb, but could be useful */
186 set_fs(KERNEL_DS);
187 DUMP_WRITE(current,sizeof(*current));
188end_coredump:
189 set_fs(fs);
190 return has_dumped;
191}
192
193/*
194 * create_aout_tables() parses the env- and arg-strings in new user
195 * memory and creates the pointer tables from them, and puts their
196 * addresses on the "stack", returning the new stack pointer value.
197 */
198static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
199{
200 char __user * __user *argv;
201 char __user * __user *envp;
202 unsigned long __user *sp;
203 int argc = bprm->argc;
204 int envc = bprm->envc;
205
206 sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
207#ifdef __sparc__
208 /* This imposes the proper stack alignment for a new process. */
209 sp = (void __user *) (((unsigned long) sp) & ~7);
210 if ((envc+argc+3)&1) --sp;
211#endif
212#ifdef __alpha__
213/* whee.. test-programs are so much fun. */
214 put_user(0, --sp);
215 put_user(0, --sp);
216 if (bprm->loader) {
217 put_user(0, --sp);
218 put_user(0x3eb, --sp);
219 put_user(bprm->loader, --sp);
220 put_user(0x3ea, --sp);
221 }
222 put_user(bprm->exec, --sp);
223 put_user(0x3e9, --sp);
224#endif
225 sp -= envc+1;
226 envp = (char __user * __user *) sp;
227 sp -= argc+1;
228 argv = (char __user * __user *) sp;
229#if defined(__i386__) || defined(__mc68000__) || defined(__arm__) || defined(__arch_um__)
230 put_user((unsigned long) envp,--sp);
231 put_user((unsigned long) argv,--sp);
232#endif
233 put_user(argc,--sp);
234 current->mm->arg_start = (unsigned long) p;
235 while (argc-->0) {
236 char c;
237 put_user(p,argv++);
238 do {
239 get_user(c,p++);
240 } while (c);
241 }
242 put_user(NULL,argv);
243 current->mm->arg_end = current->mm->env_start = (unsigned long) p;
244 while (envc-->0) {
245 char c;
246 put_user(p,envp++);
247 do {
248 get_user(c,p++);
249 } while (c);
250 }
251 put_user(NULL,envp);
252 current->mm->env_end = (unsigned long) p;
253 return sp;
254}
255
256/*
257 * These are the functions used to load a.out style executables and shared
258 * libraries. There is no binary dependent code anywhere else.
259 */
260
261static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
262{
263 struct exec ex;
264 unsigned long error;
265 unsigned long fd_offset;
266 unsigned long rlim;
267 int retval;
268
269 ex = *((struct exec *) bprm->buf); /* exec-header */
270 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
271 N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
272 N_TRSIZE(ex) || N_DRSIZE(ex) ||
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800273 i_size_read(bprm->file->f_path.dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700274 return -ENOEXEC;
275 }
276
Eugene Teo8454aee2006-09-29 01:59:33 -0700277 /*
278 * Requires a mmap handler. This prevents people from using a.out
279 * as part of an exploit attack against /proc-related vulnerabilities.
280 */
281 if (!bprm->file->f_op || !bprm->file->f_op->mmap)
282 return -ENOEXEC;
283
Linus Torvalds1da177e2005-04-16 15:20:36 -0700284 fd_offset = N_TXTOFF(ex);
285
286 /* Check initial limits. This avoids letting people circumvent
287 * size limits imposed on them by creating programs with large
288 * arrays in the data or bss.
289 */
290 rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
291 if (rlim >= RLIM_INFINITY)
292 rlim = ~0;
293 if (ex.a_data + ex.a_bss > rlim)
294 return -ENOMEM;
295
296 /* Flush all traces of the currently running executable */
297 retval = flush_old_exec(bprm);
298 if (retval)
299 return retval;
300
301 /* OK, This is the point of no return */
302#if defined(__alpha__)
303 SET_AOUT_PERSONALITY(bprm, ex);
304#elif defined(__sparc__)
305 set_personality(PER_SUNOS);
306#if !defined(__sparc_v9__)
307 memcpy(&current->thread.core_exec, &ex, sizeof(struct exec));
308#endif
309#else
310 set_personality(PER_LINUX);
311#endif
312
313 current->mm->end_code = ex.a_text +
314 (current->mm->start_code = N_TXTADDR(ex));
315 current->mm->end_data = ex.a_data +
316 (current->mm->start_data = N_DATADDR(ex));
317 current->mm->brk = ex.a_bss +
318 (current->mm->start_brk = N_BSSADDR(ex));
319 current->mm->free_area_cache = current->mm->mmap_base;
Wolfgang Wander1363c3c2005-06-21 17:14:49 -0700320 current->mm->cached_hole_size = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700321
Linus Torvalds1da177e2005-04-16 15:20:36 -0700322 compute_creds(bprm);
323 current->flags &= ~PF_FORKNOEXEC;
324#ifdef __sparc__
325 if (N_MAGIC(ex) == NMAGIC) {
326 loff_t pos = fd_offset;
327 /* Fuck me plenty... */
328 /* <AOL></AOL> */
329 down_write(&current->mm->mmap_sem);
330 error = do_brk(N_TXTADDR(ex), ex.a_text);
331 up_write(&current->mm->mmap_sem);
332 bprm->file->f_op->read(bprm->file, (char *) N_TXTADDR(ex),
333 ex.a_text, &pos);
334 down_write(&current->mm->mmap_sem);
335 error = do_brk(N_DATADDR(ex), ex.a_data);
336 up_write(&current->mm->mmap_sem);
337 bprm->file->f_op->read(bprm->file, (char *) N_DATADDR(ex),
338 ex.a_data, &pos);
339 goto beyond_if;
340 }
341#endif
342
343 if (N_MAGIC(ex) == OMAGIC) {
344 unsigned long text_addr, map_size;
345 loff_t pos;
346
347 text_addr = N_TXTADDR(ex);
348
349#if defined(__alpha__) || defined(__sparc__)
350 pos = fd_offset;
351 map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
352#else
353 pos = 32;
354 map_size = ex.a_text+ex.a_data;
355#endif
356 down_write(&current->mm->mmap_sem);
357 error = do_brk(text_addr & PAGE_MASK, map_size);
358 up_write(&current->mm->mmap_sem);
359 if (error != (text_addr & PAGE_MASK)) {
360 send_sig(SIGKILL, current, 0);
361 return error;
362 }
363
364 error = bprm->file->f_op->read(bprm->file,
365 (char __user *)text_addr,
366 ex.a_text+ex.a_data, &pos);
367 if ((signed long)error < 0) {
368 send_sig(SIGKILL, current, 0);
369 return error;
370 }
371
372 flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
373 } else {
374 static unsigned long error_time, error_time2;
375 if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
376 (N_MAGIC(ex) != NMAGIC) && (jiffies-error_time2) > 5*HZ)
377 {
378 printk(KERN_NOTICE "executable not page aligned\n");
379 error_time2 = jiffies;
380 }
381
382 if ((fd_offset & ~PAGE_MASK) != 0 &&
383 (jiffies-error_time) > 5*HZ)
384 {
385 printk(KERN_WARNING
386 "fd_offset is not page aligned. Please convert program: %s\n",
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800387 bprm->file->f_path.dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 error_time = jiffies;
389 }
390
391 if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
392 loff_t pos = fd_offset;
393 down_write(&current->mm->mmap_sem);
394 do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
395 up_write(&current->mm->mmap_sem);
396 bprm->file->f_op->read(bprm->file,
397 (char __user *)N_TXTADDR(ex),
398 ex.a_text+ex.a_data, &pos);
399 flush_icache_range((unsigned long) N_TXTADDR(ex),
400 (unsigned long) N_TXTADDR(ex) +
401 ex.a_text+ex.a_data);
402 goto beyond_if;
403 }
404
405 down_write(&current->mm->mmap_sem);
406 error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
407 PROT_READ | PROT_EXEC,
408 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
409 fd_offset);
410 up_write(&current->mm->mmap_sem);
411
412 if (error != N_TXTADDR(ex)) {
413 send_sig(SIGKILL, current, 0);
414 return error;
415 }
416
417 down_write(&current->mm->mmap_sem);
418 error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
419 PROT_READ | PROT_WRITE | PROT_EXEC,
420 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
421 fd_offset + ex.a_text);
422 up_write(&current->mm->mmap_sem);
423 if (error != N_DATADDR(ex)) {
424 send_sig(SIGKILL, current, 0);
425 return error;
426 }
427 }
428beyond_if:
429 set_binfmt(&aout_format);
430
431 retval = set_brk(current->mm->start_brk, current->mm->brk);
432 if (retval < 0) {
433 send_sig(SIGKILL, current, 0);
434 return retval;
435 }
436
437 retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
438 if (retval < 0) {
439 /* Someone check-me: is this error path enough? */
440 send_sig(SIGKILL, current, 0);
441 return retval;
442 }
443
444 current->mm->start_stack =
445 (unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
446#ifdef __alpha__
447 regs->gp = ex.a_gpvalue;
448#endif
449 start_thread(regs, ex.a_entry, current->mm->start_stack);
450 if (unlikely(current->ptrace & PT_PTRACED)) {
451 if (current->ptrace & PT_TRACE_EXEC)
452 ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
453 else
454 send_sig(SIGTRAP, current, 0);
455 }
456 return 0;
457}
458
459static int load_aout_library(struct file *file)
460{
461 struct inode * inode;
462 unsigned long bss, start_addr, len;
463 unsigned long error;
464 int retval;
465 struct exec ex;
466
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800467 inode = file->f_path.dentry->d_inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468
469 retval = -ENOEXEC;
470 error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
471 if (error != sizeof(ex))
472 goto out;
473
474 /* We come in here for the regular a.out style of shared libraries */
475 if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
476 N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
477 i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
478 goto out;
479 }
480
Eugene Teo8454aee2006-09-29 01:59:33 -0700481 /*
482 * Requires a mmap handler. This prevents people from using a.out
483 * as part of an exploit attack against /proc-related vulnerabilities.
484 */
485 if (!file->f_op || !file->f_op->mmap)
486 goto out;
487
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 if (N_FLAGS(ex))
489 goto out;
490
491 /* For QMAGIC, the starting address is 0x20 into the page. We mask
492 this off to get the starting address for the page */
493
494 start_addr = ex.a_entry & 0xfffff000;
495
496 if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
497 static unsigned long error_time;
498 loff_t pos = N_TXTOFF(ex);
499
500 if ((jiffies-error_time) > 5*HZ)
501 {
502 printk(KERN_WARNING
503 "N_TXTOFF is not page aligned. Please convert library: %s\n",
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800504 file->f_path.dentry->d_name.name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505 error_time = jiffies;
506 }
507 down_write(&current->mm->mmap_sem);
508 do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
509 up_write(&current->mm->mmap_sem);
510
511 file->f_op->read(file, (char __user *)start_addr,
512 ex.a_text + ex.a_data, &pos);
513 flush_icache_range((unsigned long) start_addr,
514 (unsigned long) start_addr + ex.a_text + ex.a_data);
515
516 retval = 0;
517 goto out;
518 }
519 /* Now use mmap to map the library into memory. */
520 down_write(&current->mm->mmap_sem);
521 error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
522 PROT_READ | PROT_WRITE | PROT_EXEC,
523 MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
524 N_TXTOFF(ex));
525 up_write(&current->mm->mmap_sem);
526 retval = error;
527 if (error != start_addr)
528 goto out;
529
530 len = PAGE_ALIGN(ex.a_text + ex.a_data);
531 bss = ex.a_text + ex.a_data + ex.a_bss;
532 if (bss > len) {
533 down_write(&current->mm->mmap_sem);
534 error = do_brk(start_addr + len, bss - len);
535 up_write(&current->mm->mmap_sem);
536 retval = error;
537 if (error != start_addr + len)
538 goto out;
539 }
540 retval = 0;
541out:
542 return retval;
543}
544
545static int __init init_aout_binfmt(void)
546{
547 return register_binfmt(&aout_format);
548}
549
550static void __exit exit_aout_binfmt(void)
551{
552 unregister_binfmt(&aout_format);
553}
554
555core_initcall(init_aout_binfmt);
556module_exit(exit_aout_binfmt);
557MODULE_LICENSE("GPL");