aboutsummaryrefslogtreecommitdiffstats
path: root/fs/binfmt_aout.c
blob: 72011826f0cb340aabc54f65ee7d31653fc7d364 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
/*
 *  linux/fs/binfmt_aout.c
 *
 *  Copyright (C) 1991, 1992, 1996  Linus Torvalds
 */

#include <linux/module.h>

#include <linux/time.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/a.out.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/string.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/user.h>
#include <linux/slab.h>
#include <linux/binfmts.h>
#include <linux/personality.h>
#include <linux/init.h>

#include <asm/system.h>
#include <asm/uaccess.h>
#include <asm/cacheflush.h>

static int load_aout_binary(struct linux_binprm *, struct pt_regs * regs);
static int load_aout_library(struct file*);
static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file);

extern void dump_thread(struct pt_regs *, struct user *);

static struct linux_binfmt aout_format = {
	.module		= THIS_MODULE,
	.load_binary	= load_aout_binary,
	.load_shlib	= load_aout_library,
	.core_dump	= aout_core_dump,
	.min_coredump	= PAGE_SIZE
};

#define BAD_ADDR(x)	((unsigned long)(x) >= TASK_SIZE)

static int set_brk(unsigned long start, unsigned long end)
{
	start = PAGE_ALIGN(start);
	end = PAGE_ALIGN(end);
	if (end > start) {
		unsigned long addr;
		down_write(&current->mm->mmap_sem);
		addr = do_brk(start, end - start);
		up_write(&current->mm->mmap_sem);
		if (BAD_ADDR(addr))
			return addr;
	}
	return 0;
}

/*
 * These are the only things you should do on a core-file: use only these
 * macros to write out all the necessary info.
 */

static int dump_write(struct file *file, const void *addr, int nr)
{
	return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
}

#define DUMP_WRITE(addr, nr)	\
	if (!dump_write(file, (void *)(addr), (nr))) \
		goto end_coredump;

#define DUMP_SEEK(offset) \
if (file->f_op->llseek) { \
	if (file->f_op->llseek(file,(offset),0) != (offset)) \
 		goto end_coredump; \
} else file->f_pos = (offset)

/*
 * Routine writes a core dump image in the current directory.
 * Currently only a stub-function.
 *
 * Note that setuid/setgid files won't make a core-dump if the uid/gid
 * changed due to the set[u|g]id. It's enforced by the "current->mm->dumpable"
 * field, which also makes sure the core-dumps won't be recursive if the
 * dumping of the process results in another error..
 */

static int aout_core_dump(long signr, struct pt_regs * regs, struct file *file)
{
	mm_segment_t fs;
	int has_dumped = 0;
	unsigned long dump_start, dump_size;
	struct user dump;
#if defined(__alpha__)
#       define START_DATA(u)	(u.start_data)
#elif defined(__arm__)
#	define START_DATA(u)	((u.u_tsize << PAGE_SHIFT) + u.start_code)
#elif defined(__sparc__)
#       define START_DATA(u)    (u.u_tsize)
#elif defined(__i386__) || defined(__mc68000__) || defined(__arch_um__)
#       define START_DATA(u)	(u.u_tsize << PAGE_SHIFT)
#endif
#ifdef __sparc__
#       define START_STACK(u)   ((regs->u_regs[UREG_FP]) & ~(PAGE_SIZE - 1))
#else
#       define START_STACK(u)   (u.start_stack)
#endif

	fs = get_fs();
	set_fs(KERNEL_DS);
	has_dumped = 1;
	current->flags |= PF_DUMPCORE;
       	strncpy(dump.u_comm, current->comm, sizeof(dump.u_comm));
#ifndef __sparc__
	dump.u_ar0 = (void *)(((unsigned long)(&dump.regs)) - ((unsigned long)(&dump)));
#endif
	dump.signal = signr;
	dump_thread(regs, &dump);

/* If the size of the dump file exceeds the rlimit, then see what would happen
   if we wrote the stack, but not the data area.  */
#ifdef __sparc__
	if ((dump.u_dsize+dump.u_ssize) >
	    current->signal->rlim[RLIMIT_CORE].rlim_cur)
		dump.u_dsize = 0;
#else
	if ((dump.u_dsize+dump.u_ssize+1) * PAGE_SIZE >
	    current->signal->rlim[RLIMIT_CORE].rlim_cur)
		dump.u_dsize = 0;
#endif

/* Make sure we have enough room to write the stack and data areas. */
#ifdef __sparc__
	if ((dump.u_ssize) >
	    current->signal->rlim[RLIMIT_CORE].rlim_cur)
		dump.u_ssize = 0;
#else
	if ((dump.u_ssize+1) * PAGE_SIZE >
	    current->signal->rlim[RLIMIT_CORE].rlim_cur)
		dump.u_ssize = 0;
#endif

/* make sure we actually have a data and stack area to dump */
	set_fs(USER_DS);
#ifdef __sparc__
	if (!access_ok(VERIFY_READ, (void __user *)START_DATA(dump), dump.u_dsize))
		dump.u_dsize = 0;
	if (!access_ok(VERIFY_READ, (void __user *)START_STACK(dump), dump.u_ssize))
		dump.u_ssize = 0;
#else
	if (!access_ok(VERIFY_READ, (void __user *)START_DATA(dump), dump.u_dsize << PAGE_SHIFT))
		dump.u_dsize = 0;
	if (!access_ok(VERIFY_READ, (void __user *)START_STACK(dump), dump.u_ssize << PAGE_SHIFT))
		dump.u_ssize = 0;
#endif

	set_fs(KERNEL_DS);
/* struct user */
	DUMP_WRITE(&dump,sizeof(dump));
/* Now dump all of the user data.  Include malloced stuff as well */
#ifndef __sparc__
	DUMP_SEEK(PAGE_SIZE);
#endif
/* now we start writing out the user space info */
	set_fs(USER_DS);
/* Dump the data area */
	if (dump.u_dsize != 0) {
		dump_start = START_DATA(dump);
#ifdef __sparc__
		dump_size = dump.u_dsize;
#else
		dump_size = dump.u_dsize << PAGE_SHIFT;
#endif
		DUMP_WRITE(dump_start,dump_size);
	}
/* Now prepare to dump the stack area */
	if (dump.u_ssize != 0) {
		dump_start = START_STACK(dump);
#ifdef __sparc__
		dump_size = dump.u_ssize;
#else
		dump_size = dump.u_ssize << PAGE_SHIFT;
#endif
		DUMP_WRITE(dump_start,dump_size);
	}
/* Finally dump the task struct.  Not be used by gdb, but could be useful */
	set_fs(KERNEL_DS);
	DUMP_WRITE(current,sizeof(*current));
end_coredump:
	set_fs(fs);
	return has_dumped;
}

/*
 * create_aout_tables() parses the env- and arg-strings in new user
 * memory and creates the pointer tables from them, and puts their
 * addresses on the "stack", returning the new stack pointer value.
 */
static unsigned long __user *create_aout_tables(char __user *p, struct linux_binprm * bprm)
{
	char __user * __user *argv;
	char __user * __user *envp;
	unsigned long __user *sp;
	int argc = bprm->argc;
	int envc = bprm->envc;

	sp = (void __user *)((-(unsigned long)sizeof(char *)) & (unsigned long) p);
#ifdef __sparc__
	/* This imposes the proper stack alignment for a new process. */
	sp = (void __user *) (((unsigned long) sp) & ~7);
	if ((envc+argc+3)&1) --sp;
#endif
#ifdef __alpha__
/* whee.. test-programs are so much fun. */
	put_user(0, --sp);
	put_user(0, --sp);
	if (bprm->loader) {
		put_user(0, --sp);
		put_user(0x3eb, --sp);
		put_user(bprm->loader, --sp);
		put_user(0x3ea, --sp);
	}
	put_user(bprm->exec, --sp);
	put_user(0x3e9, --sp);
#endif
	sp -= envc+1;
	envp = (char __user * __user *) sp;
	sp -= argc+1;
	argv = (char __user * __user *) sp;
#if defined(__i386__) || defined(__mc68000__) || defined(__arm__) || defined(__arch_um__)
	put_user((unsigned long) envp,--sp);
	put_user((unsigned long) argv,--sp);
#endif
	put_user(argc,--sp);
	current->mm->arg_start = (unsigned long) p;
	while (argc-->0) {
		char c;
		put_user(p,argv++);
		do {
			get_user(c,p++);
		} while (c);
	}
	put_user(NULL,argv);
	current->mm->arg_end = current->mm->env_start = (unsigned long) p;
	while (envc-->0) {
		char c;
		put_user(p,envp++);
		do {
			get_user(c,p++);
		} while (c);
	}
	put_user(NULL,envp);
	current->mm->env_end = (unsigned long) p;
	return sp;
}

/*
 * These are the functions used to load a.out style executables and shared
 * libraries.  There is no binary dependent code anywhere else.
 */

static int load_aout_binary(struct linux_binprm * bprm, struct pt_regs * regs)
{
	struct exec ex;
	unsigned long error;
	unsigned long fd_offset;
	unsigned long rlim;
	int retval;

	ex = *((struct exec *) bprm->buf);		/* exec-header */
	if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != OMAGIC &&
	     N_MAGIC(ex) != QMAGIC && N_MAGIC(ex) != NMAGIC) ||
	    N_TRSIZE(ex) || N_DRSIZE(ex) ||
	    i_size_read(bprm->file->f_dentry->d_inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
		return -ENOEXEC;
	}

	fd_offset = N_TXTOFF(ex);

	/* Check initial limits. This avoids letting people circumvent
	 * size limits imposed on them by creating programs with large
	 * arrays in the data or bss.
	 */
	rlim = current->signal->rlim[RLIMIT_DATA].rlim_cur;
	if (rlim >= RLIM_INFINITY)
		rlim = ~0;
	if (ex.a_data + ex.a_bss > rlim)
		return -ENOMEM;

	/* Flush all traces of the currently running executable */
	retval = flush_old_exec(bprm);
	if (retval)
		return retval;

	/* OK, This is the point of no return */
#if defined(__alpha__)
	SET_AOUT_PERSONALITY(bprm, ex);
#elif defined(__sparc__)
	set_personality(PER_SUNOS);
#if !defined(__sparc_v9__)
	memcpy(&current->thread.core_exec, &ex, sizeof(struct exec));
#endif
#else
	set_personality(PER_LINUX);
#endif

	current->mm->end_code = ex.a_text +
		(current->mm->start_code = N_TXTADDR(ex));
	current->mm->end_data = ex.a_data +
		(current->mm->start_data = N_DATADDR(ex));
	current->mm->brk = ex.a_bss +
		(current->mm->start_brk = N_BSSADDR(ex));
	current->mm->free_area_cache = current->mm->mmap_base;
	current->mm->cached_hole_size = 0;

	current->mm->mmap = NULL;
	compute_creds(bprm);
 	current->flags &= ~PF_FORKNOEXEC;
#ifdef __sparc__
	if (N_MAGIC(ex) == NMAGIC) {
		loff_t pos = fd_offset;
		/* Fuck me plenty... */
		/* <AOL></AOL> */
		down_write(&current->mm->mmap_sem);	
		error = do_brk(N_TXTADDR(ex), ex.a_text);
		up_write(&current->mm->mmap_sem);
		bprm->file->f_op->read(bprm->file, (char *) N_TXTADDR(ex),
			  ex.a_text, &pos);
		down_write(&current->mm->mmap_sem);
		error = do_brk(N_DATADDR(ex), ex.a_data);
		up_write(&current->mm->mmap_sem);
		bprm->file->f_op->read(bprm->file, (char *) N_DATADDR(ex),
			  ex.a_data, &pos);
		goto beyond_if;
	}
#endif

	if (N_MAGIC(ex) == OMAGIC) {
		unsigned long text_addr, map_size;
		loff_t pos;

		text_addr = N_TXTADDR(ex);

#if defined(__alpha__) || defined(__sparc__)
		pos = fd_offset;
		map_size = ex.a_text+ex.a_data + PAGE_SIZE - 1;
#else
		pos = 32;
		map_size = ex.a_text+ex.a_data;
#endif
		down_write(&current->mm->mmap_sem);
		error = do_brk(text_addr & PAGE_MASK, map_size);
		up_write(&current->mm->mmap_sem);
		if (error != (text_addr & PAGE_MASK)) {
			send_sig(SIGKILL, current, 0);
			return error;
		}

		error = bprm->file->f_op->read(bprm->file,
			  (char __user *)text_addr,
			  ex.a_text+ex.a_data, &pos);
		if ((signed long)error < 0) {
			send_sig(SIGKILL, current, 0);
			return error;
		}
			 
		flush_icache_range(text_addr, text_addr+ex.a_text+ex.a_data);
	} else {
		static unsigned long error_time, error_time2;
		if ((ex.a_text & 0xfff || ex.a_data & 0xfff) &&
		    (N_MAGIC(ex) != NMAGIC) && (jiffies-error_time2) > 5*HZ)
		{
			printk(KERN_NOTICE "executable not page aligned\n");
			error_time2 = jiffies;
		}

		if ((fd_offset & ~PAGE_MASK) != 0 &&
		    (jiffies-error_time) > 5*HZ)
		{
			printk(KERN_WARNING 
			       "fd_offset is not page aligned. Please convert program: %s\n",
			       bprm->file->f_dentry->d_name.name);
			error_time = jiffies;
		}

		if (!bprm->file->f_op->mmap||((fd_offset & ~PAGE_MASK) != 0)) {
			loff_t pos = fd_offset;
			down_write(&current->mm->mmap_sem);
			do_brk(N_TXTADDR(ex), ex.a_text+ex.a_data);
			up_write(&current->mm->mmap_sem);
			bprm->file->f_op->read(bprm->file,
					(char __user *)N_TXTADDR(ex),
					ex.a_text+ex.a_data, &pos);
			flush_icache_range((unsigned long) N_TXTADDR(ex),
					   (unsigned long) N_TXTADDR(ex) +
					   ex.a_text+ex.a_data);
			goto beyond_if;
		}

		down_write(&current->mm->mmap_sem);
		error = do_mmap(bprm->file, N_TXTADDR(ex), ex.a_text,
			PROT_READ | PROT_EXEC,
			MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
			fd_offset);
		up_write(&current->mm->mmap_sem);

		if (error != N_TXTADDR(ex)) {
			send_sig(SIGKILL, current, 0);
			return error;
		}

		down_write(&current->mm->mmap_sem);
 		error = do_mmap(bprm->file, N_DATADDR(ex), ex.a_data,
				PROT_READ | PROT_WRITE | PROT_EXEC,
				MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE,
				fd_offset + ex.a_text);
		up_write(&current->mm->mmap_sem);
		if (error != N_DATADDR(ex)) {
			send_sig(SIGKILL, current, 0);
			return error;
		}
	}
beyond_if:
	set_binfmt(&aout_format);

	retval = set_brk(current->mm->start_brk, current->mm->brk);
	if (retval < 0) {
		send_sig(SIGKILL, current, 0);
		return retval;
	}

	retval = setup_arg_pages(bprm, STACK_TOP, EXSTACK_DEFAULT);
	if (retval < 0) { 
		/* Someone check-me: is this error path enough? */ 
		send_sig(SIGKILL, current, 0); 
		return retval;
	}

	current->mm->start_stack =
		(unsigned long) create_aout_tables((char __user *) bprm->p, bprm);
#ifdef __alpha__
	regs->gp = ex.a_gpvalue;
#endif
	start_thread(regs, ex.a_entry, current->mm->start_stack);
	if (unlikely(current->ptrace & PT_PTRACED)) {
		if (current->ptrace & PT_TRACE_EXEC)
			ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
		else
			send_sig(SIGTRAP, current, 0);
	}
	return 0;
}

static int load_aout_library(struct file *file)
{
	struct inode * inode;
	unsigned long bss, start_addr, len;
	unsigned long error;
	int retval;
	struct exec ex;

	inode = file->f_dentry->d_inode;

	retval = -ENOEXEC;
	error = kernel_read(file, 0, (char *) &ex, sizeof(ex));
	if (error != sizeof(ex))
		goto out;

	/* We come in here for the regular a.out style of shared libraries */
	if ((N_MAGIC(ex) != ZMAGIC && N_MAGIC(ex) != QMAGIC) || N_TRSIZE(ex) ||
	    N_DRSIZE(ex) || ((ex.a_entry & 0xfff) && N_MAGIC(ex) == ZMAGIC) ||
	    i_size_read(inode) < ex.a_text+ex.a_data+N_SYMSIZE(ex)+N_TXTOFF(ex)) {
		goto out;
	}

	if (N_FLAGS(ex))
		goto out;

	/* For  QMAGIC, the starting address is 0x20 into the page.  We mask
	   this off to get the starting address for the page */

	start_addr =  ex.a_entry & 0xfffff000;

	if ((N_TXTOFF(ex) & ~PAGE_MASK) != 0) {
		static unsigned long error_time;
		loff_t pos = N_TXTOFF(ex);

		if ((jiffies-error_time) > 5*HZ)
		{
			printk(KERN_WARNING 
			       "N_TXTOFF is not page aligned. Please convert library: %s\n",
			       file->f_dentry->d_name.name);
			error_time = jiffies;
		}
		down_write(&current->mm->mmap_sem);
		do_brk(start_addr, ex.a_text + ex.a_data + ex.a_bss);
		up_write(&current->mm->mmap_sem);
		
		file->f_op->read(file, (char __user *)start_addr,
			ex.a_text + ex.a_data, &pos);
		flush_icache_range((unsigned long) start_addr,
				   (unsigned long) start_addr + ex.a_text + ex.a_data);

		retval = 0;
		goto out;
	}
	/* Now use mmap to map the library into memory. */
	down_write(&current->mm->mmap_sem);
	error = do_mmap(file, start_addr, ex.a_text + ex.a_data,
			PROT_READ | PROT_WRITE | PROT_EXEC,
			MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
			N_TXTOFF(ex));
	up_write(&current->mm->mmap_sem);
	retval = error;
	if (error != start_addr)
		goto out;

	len = PAGE_ALIGN(ex.a_text + ex.a_data);
	bss = ex.a_text + ex.a_data + ex.a_bss;
	if (bss > len) {
		down_write(&current->mm->mmap_sem);
		error = do_brk(start_addr + len, bss - len);
		up_write(&current->mm->mmap_sem);
		retval = error;
		if (error != start_addr + len)
			goto out;
	}
	retval = 0;
out:
	return retval;
}

static int __init init_aout_binfmt(void)
{
	return register_binfmt(&aout_format);
}

static void __exit exit_aout_binfmt(void)
{
	unregister_binfmt(&aout_format);
}

core_initcall(init_aout_binfmt);
module_exit(exit_aout_binfmt);
MODULE_LICENSE("GPL");