binfmt_elf.c 60.8 KB
Newer Older
Linus Torvalds's avatar
Linus Torvalds committed
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
/*
 * linux/fs/binfmt_elf.c
 *
 * These are the functions used to load ELF format executables as used
 * on SVr4 machines.  Information on the format may be found in the book
 * "UNIX SYSTEM V RELEASE 4 Programmers Guide: Ansi C and Programming Support
 * Tools".
 *
 * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/binfmts.h>
#include <linux/string.h>
#include <linux/file.h>
#include <linux/slab.h>
#include <linux/personality.h>
#include <linux/elfcore.h>
#include <linux/init.h>
#include <linux/highuid.h>
#include <linux/compiler.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
30
#include <linux/vmalloc.h>
Linus Torvalds's avatar
Linus Torvalds committed
31
32
#include <linux/security.h>
#include <linux/random.h>
33
#include <linux/elf.h>
34
#include <linux/utsname.h>
35
#include <linux/coredump.h>
36
#include <linux/sched.h>
Linus Torvalds's avatar
Linus Torvalds committed
37
38
39
40
#include <asm/uaccess.h>
#include <asm/param.h>
#include <asm/page.h>

41
42
43
#ifndef user_long_t
#define user_long_t long
#endif
44
45
46
47
#ifndef user_siginfo_t
#define user_siginfo_t siginfo_t
#endif

48
static int load_elf_binary(struct linux_binprm *bprm);
49
50
static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *,
				int, int, unsigned long);
Linus Torvalds's avatar
Linus Torvalds committed
51

52
53
54
55
56
57
#ifdef CONFIG_USELIB
static int load_elf_library(struct file *);
#else
#define load_elf_library NULL
#endif

Linus Torvalds's avatar
Linus Torvalds committed
58
59
60
61
/*
 * If we don't support core dumping, then supply a NULL so we
 * don't even try.
 */
62
#ifdef CONFIG_ELF_CORE
63
static int elf_core_dump(struct coredump_params *cprm);
Linus Torvalds's avatar
Linus Torvalds committed
64
65
66
67
68
#else
#define elf_core_dump	NULL
#endif

#if ELF_EXEC_PAGESIZE > PAGE_SIZE
69
#define ELF_MIN_ALIGN	ELF_EXEC_PAGESIZE
Linus Torvalds's avatar
Linus Torvalds committed
70
#else
71
#define ELF_MIN_ALIGN	PAGE_SIZE
Linus Torvalds's avatar
Linus Torvalds committed
72
73
74
75
76
77
78
79
80
81
82
#endif

#ifndef ELF_CORE_EFLAGS
#define ELF_CORE_EFLAGS	0
#endif

#define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
#define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
#define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))

static struct linux_binfmt elf_format = {
Mikael Pettersson's avatar
Mikael Pettersson committed
83
84
85
86
87
	.module		= THIS_MODULE,
	.load_binary	= load_elf_binary,
	.load_shlib	= load_elf_library,
	.core_dump	= elf_core_dump,
	.min_coredump	= ELF_EXEC_PAGESIZE,
Linus Torvalds's avatar
Linus Torvalds committed
88
89
};

Andrew Morton's avatar
Andrew Morton committed
90
#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
Linus Torvalds's avatar
Linus Torvalds committed
91
92
93
94
95
96
97

static int set_brk(unsigned long start, unsigned long end)
{
	start = ELF_PAGEALIGN(start);
	end = ELF_PAGEALIGN(end);
	if (end > start) {
		unsigned long addr;
98
		addr = vm_brk(start, end - start);
Linus Torvalds's avatar
Linus Torvalds committed
99
100
101
102
103
104
105
106
107
108
		if (BAD_ADDR(addr))
			return addr;
	}
	current->mm->start_brk = current->mm->brk = end;
	return 0;
}

/* We need to explicitly zero any fractional pages
   after the data section (i.e. bss).  This would
   contain the junk from the file that should not
109
110
   be in memory
 */
Linus Torvalds's avatar
Linus Torvalds committed
111
112
113
114
115
116
117
118
119
120
121
122
123
static int padzero(unsigned long elf_bss)
{
	unsigned long nbyte;

	nbyte = ELF_PAGEOFFSET(elf_bss);
	if (nbyte) {
		nbyte = ELF_MIN_ALIGN - nbyte;
		if (clear_user((void __user *) elf_bss, nbyte))
			return -EFAULT;
	}
	return 0;
}

Ohad Ben-Cohen's avatar
Ohad Ben-Cohen committed
124
/* Let's use some macros to make this stack manipulation a little clearer */
Linus Torvalds's avatar
Linus Torvalds committed
125
126
127
128
#ifdef CONFIG_STACK_GROWSUP
#define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) + (items))
#define STACK_ROUND(sp, items) \
	((15 + (unsigned long) ((sp) + (items))) &~ 15UL)
129
130
131
#define STACK_ALLOC(sp, len) ({ \
	elf_addr_t __user *old_sp = (elf_addr_t __user *)sp; sp += len; \
	old_sp; })
Linus Torvalds's avatar
Linus Torvalds committed
132
133
134
135
136
137
138
#else
#define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) - (items))
#define STACK_ROUND(sp, items) \
	(((unsigned long) (sp - items)) &~ 15UL)
#define STACK_ALLOC(sp, len) ({ sp -= len ; sp; })
#endif

139
140
141
142
143
144
145
146
147
#ifndef ELF_BASE_PLATFORM
/*
 * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
 * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
 * will be copied to the user stack in the same manner as AT_PLATFORM.
 */
#define ELF_BASE_PLATFORM NULL
#endif

Linus Torvalds's avatar
Linus Torvalds committed
148
static int
149
create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
150
		unsigned long load_addr, unsigned long interp_load_addr)
Linus Torvalds's avatar
Linus Torvalds committed
151
152
153
154
155
156
157
158
{
	unsigned long p = bprm->p;
	int argc = bprm->argc;
	int envc = bprm->envc;
	elf_addr_t __user *argv;
	elf_addr_t __user *envp;
	elf_addr_t __user *sp;
	elf_addr_t __user *u_platform;
159
	elf_addr_t __user *u_base_platform;
160
	elf_addr_t __user *u_rand_bytes;
Linus Torvalds's avatar
Linus Torvalds committed
161
	const char *k_platform = ELF_PLATFORM;
162
	const char *k_base_platform = ELF_BASE_PLATFORM;
163
	unsigned char k_rand_bytes[16];
Linus Torvalds's avatar
Linus Torvalds committed
164
165
166
	int items;
	elf_addr_t *elf_info;
	int ei_index = 0;
167
	const struct cred *cred = current_cred();
168
	struct vm_area_struct *vma;
Linus Torvalds's avatar
Linus Torvalds committed
169

170
171
172
173
174
175
176
177
	/*
	 * In some cases (e.g. Hyper-Threading), we want to avoid L1
	 * evictions by the processes running on the same package. One
	 * thing we can do is to shuffle the initial stack for them.
	 */

	p = arch_align_stack(p);

Linus Torvalds's avatar
Linus Torvalds committed
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
	/*
	 * If this architecture has a platform capability string, copy it
	 * to userspace.  In some cases (Sparc), this info is impossible
	 * for userspace to get any other way, in others (i386) it is
	 * merely difficult.
	 */
	u_platform = NULL;
	if (k_platform) {
		size_t len = strlen(k_platform) + 1;

		u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
		if (__copy_to_user(u_platform, k_platform, len))
			return -EFAULT;
	}

193
194
195
196
197
198
199
200
201
202
203
204
205
	/*
	 * If this architecture has a "base" platform capability
	 * string, copy it to userspace.
	 */
	u_base_platform = NULL;
	if (k_base_platform) {
		size_t len = strlen(k_base_platform) + 1;

		u_base_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
		if (__copy_to_user(u_base_platform, k_base_platform, len))
			return -EFAULT;
	}

206
207
208
209
210
211
212
213
214
	/*
	 * Generate 16 random bytes for userspace PRNG seeding.
	 */
	get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));
	u_rand_bytes = (elf_addr_t __user *)
		       STACK_ALLOC(p, sizeof(k_rand_bytes));
	if (__copy_to_user(u_rand_bytes, k_rand_bytes, sizeof(k_rand_bytes)))
		return -EFAULT;

Linus Torvalds's avatar
Linus Torvalds committed
215
	/* Create the ELF interpreter info */
216
	elf_info = (elf_addr_t *)current->mm->saved_auxv;
217
	/* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */
Linus Torvalds's avatar
Linus Torvalds committed
218
#define NEW_AUX_ENT(id, val) \
219
	do { \
220
221
		elf_info[ei_index++] = id; \
		elf_info[ei_index++] = val; \
222
	} while (0)
Linus Torvalds's avatar
Linus Torvalds committed
223
224
225
226
227

#ifdef ARCH_DLINFO
	/* 
	 * ARCH_DLINFO must come first so PPC can do its special alignment of
	 * AUXV.
228
229
	 * update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT() in
	 * ARCH_DLINFO changes
Linus Torvalds's avatar
Linus Torvalds committed
230
231
232
233
234
235
236
	 */
	ARCH_DLINFO;
#endif
	NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
	NEW_AUX_ENT(AT_PAGESZ, ELF_EXEC_PAGESIZE);
	NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
	NEW_AUX_ENT(AT_PHDR, load_addr + exec->e_phoff);
237
	NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
Linus Torvalds's avatar
Linus Torvalds committed
238
239
240
241
	NEW_AUX_ENT(AT_PHNUM, exec->e_phnum);
	NEW_AUX_ENT(AT_BASE, interp_load_addr);
	NEW_AUX_ENT(AT_FLAGS, 0);
	NEW_AUX_ENT(AT_ENTRY, exec->e_entry);
242
243
244
245
	NEW_AUX_ENT(AT_UID, from_kuid_munged(cred->user_ns, cred->uid));
	NEW_AUX_ENT(AT_EUID, from_kuid_munged(cred->user_ns, cred->euid));
	NEW_AUX_ENT(AT_GID, from_kgid_munged(cred->user_ns, cred->gid));
	NEW_AUX_ENT(AT_EGID, from_kgid_munged(cred->user_ns, cred->egid));
246
 	NEW_AUX_ENT(AT_SECURE, security_bprm_secureexec(bprm));
247
	NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
248
249
250
#ifdef ELF_HWCAP2
	NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2);
#endif
251
	NEW_AUX_ENT(AT_EXECFN, bprm->exec);
Linus Torvalds's avatar
Linus Torvalds committed
252
	if (k_platform) {
253
		NEW_AUX_ENT(AT_PLATFORM,
254
			    (elf_addr_t)(unsigned long)u_platform);
Linus Torvalds's avatar
Linus Torvalds committed
255
	}
256
257
258
259
	if (k_base_platform) {
		NEW_AUX_ENT(AT_BASE_PLATFORM,
			    (elf_addr_t)(unsigned long)u_base_platform);
	}
Linus Torvalds's avatar
Linus Torvalds committed
260
	if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
261
		NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
Linus Torvalds's avatar
Linus Torvalds committed
262
263
264
265
266
267
268
269
270
271
272
	}
#undef NEW_AUX_ENT
	/* AT_NULL is zero; clear the rest too */
	memset(&elf_info[ei_index], 0,
	       sizeof current->mm->saved_auxv - ei_index * sizeof elf_info[0]);

	/* And advance past the AT_NULL entry.  */
	ei_index += 2;

	sp = STACK_ADD(p, ei_index);

273
	items = (argc + 1) + (envc + 1) + 1;
Linus Torvalds's avatar
Linus Torvalds committed
274
275
276
277
278
	bprm->p = STACK_ROUND(sp, items);

	/* Point sp at the lowest address on the stack */
#ifdef CONFIG_STACK_GROWSUP
	sp = (elf_addr_t __user *)bprm->p - items - ei_index;
279
	bprm->exec = (unsigned long)sp; /* XXX: PARISC HACK */
Linus Torvalds's avatar
Linus Torvalds committed
280
281
282
283
#else
	sp = (elf_addr_t __user *)bprm->p;
#endif

284
285
286
287
288
289
290
291
292

	/*
	 * Grow the stack manually; some architectures have a limit on how
	 * far ahead a user-space access may be in order to grow the stack.
	 */
	vma = find_extend_vma(current->mm, bprm->p);
	if (!vma)
		return -EFAULT;

Linus Torvalds's avatar
Linus Torvalds committed
293
294
295
	/* Now, let's put argc (and argv, envp if appropriate) on the stack */
	if (__put_user(argc, sp++))
		return -EFAULT;
296
297
	argv = sp;
	envp = argv + argc + 1;
Linus Torvalds's avatar
Linus Torvalds committed
298
299

	/* Populate argv and envp */
300
	p = current->mm->arg_end = current->mm->arg_start;
Linus Torvalds's avatar
Linus Torvalds committed
301
302
	while (argc-- > 0) {
		size_t len;
303
304
		if (__put_user((elf_addr_t)p, argv++))
			return -EFAULT;
305
306
		len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
		if (!len || len > MAX_ARG_STRLEN)
307
			return -EINVAL;
Linus Torvalds's avatar
Linus Torvalds committed
308
309
310
311
312
313
314
		p += len;
	}
	if (__put_user(0, argv))
		return -EFAULT;
	current->mm->arg_end = current->mm->env_start = p;
	while (envc-- > 0) {
		size_t len;
315
316
		if (__put_user((elf_addr_t)p, envp++))
			return -EFAULT;
317
318
		len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
		if (!len || len > MAX_ARG_STRLEN)
319
			return -EINVAL;
Linus Torvalds's avatar
Linus Torvalds committed
320
321
322
323
324
325
326
327
328
329
330
331
332
		p += len;
	}
	if (__put_user(0, envp))
		return -EFAULT;
	current->mm->env_end = p;

	/* Put the elf_info on the stack in the right place.  */
	sp = (elf_addr_t __user *)envp + 1;
	if (copy_to_user(sp, elf_info, ei_index * sizeof(elf_addr_t)))
		return -EFAULT;
	return 0;
}

333
334
#ifndef elf_map

Linus Torvalds's avatar
Linus Torvalds committed
335
static unsigned long elf_map(struct file *filep, unsigned long addr,
336
337
		struct elf_phdr *eppnt, int prot, int type,
		unsigned long total_size)
Linus Torvalds's avatar
Linus Torvalds committed
338
339
{
	unsigned long map_addr;
340
341
342
343
	unsigned long size = eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr);
	unsigned long off = eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr);
	addr = ELF_PAGESTART(addr);
	size = ELF_PAGEALIGN(size);
Linus Torvalds's avatar
Linus Torvalds committed
344

345
346
	/* mmap() will return -EINVAL if given a zero size, but a
	 * segment with zero filesize is perfectly valid */
347
348
349
350
351
352
353
354
355
356
357
358
359
	if (!size)
		return addr;

	/*
	* total_size is the size of the ELF (interpreter) image.
	* The _first_ mmap needs to know the full size, otherwise
	* randomization might put this image into an overlapping
	* position with the ELF binary image. (since size < total_size)
	* So we first map the 'big' image - and unmap the remainder at
	* the end. (which unmap is needed for ELF images with holes.)
	*/
	if (total_size) {
		total_size = ELF_PAGEALIGN(total_size);
360
		map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
361
		if (!BAD_ADDR(map_addr))
362
			vm_munmap(map_addr+size, total_size-size);
363
	} else
364
		map_addr = vm_mmap(filep, addr, size, prot, type, off);
365

Linus Torvalds's avatar
Linus Torvalds committed
366
367
368
	return(map_addr);
}

369
370
#endif /* !elf_map */

371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
static unsigned long total_mapping_size(struct elf_phdr *cmds, int nr)
{
	int i, first_idx = -1, last_idx = -1;

	for (i = 0; i < nr; i++) {
		if (cmds[i].p_type == PT_LOAD) {
			last_idx = i;
			if (first_idx == -1)
				first_idx = i;
		}
	}
	if (first_idx == -1)
		return 0;

	return cmds[last_idx].p_vaddr + cmds[last_idx].p_memsz -
				ELF_PAGESTART(cmds[first_idx].p_vaddr);
}

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
/**
 * load_elf_phdrs() - load ELF program headers
 * @elf_ex:   ELF header of the binary whose program headers should be loaded
 * @elf_file: the opened ELF binary file
 *
 * Loads ELF program headers from the binary file elf_file, which has the ELF
 * header pointed to by elf_ex, into a newly allocated array. The caller is
 * responsible for freeing the allocated data. Returns an ERR_PTR upon failure.
 */
static struct elf_phdr *load_elf_phdrs(struct elfhdr *elf_ex,
				       struct file *elf_file)
{
	struct elf_phdr *elf_phdata = NULL;
	int retval, size, err = -1;

	/*
	 * If the size of this structure has changed, then punt, since
	 * we will be doing the wrong thing.
	 */
	if (elf_ex->e_phentsize != sizeof(struct elf_phdr))
		goto out;

	/* Sanity check the number of program headers... */
	if (elf_ex->e_phnum < 1 ||
		elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr))
		goto out;

	/* ...and their total size. */
	size = sizeof(struct elf_phdr) * elf_ex->e_phnum;
	if (size > ELF_MIN_ALIGN)
		goto out;

	elf_phdata = kmalloc(size, GFP_KERNEL);
	if (!elf_phdata)
		goto out;

	/* Read in the program headers */
	retval = kernel_read(elf_file, elf_ex->e_phoff,
			     (char *)elf_phdata, size);
	if (retval != size) {
		err = (retval < 0) ? retval : -EIO;
		goto out;
	}

	/* Success! */
	err = 0;
out:
	if (err) {
		kfree(elf_phdata);
		elf_phdata = NULL;
	}
	return elf_phdata;
}
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
#ifndef CONFIG_ARCH_BINFMT_ELF_STATE

/**
 * struct arch_elf_state - arch-specific ELF loading state
 *
 * This structure is used to preserve architecture specific data during
 * the loading of an ELF file, throughout the checking of architecture
 * specific ELF headers & through to the point where the ELF load is
 * known to be proceeding (ie. SET_PERSONALITY).
 *
 * This implementation is a dummy for architectures which require no
 * specific state.
 */
struct arch_elf_state {
};

#define INIT_ARCH_ELF_STATE {}

/**
 * arch_elf_pt_proc() - check a PT_LOPROC..PT_HIPROC ELF program header
 * @ehdr:	The main ELF header
 * @phdr:	The program header to check
 * @elf:	The open ELF file
 * @is_interp:	True if the phdr is from the interpreter of the ELF being
 *		loaded, else false.
 * @state:	Architecture-specific state preserved throughout the process
 *		of loading the ELF.
 *
 * Inspects the program header phdr to validate its correctness and/or
 * suitability for the system. Called once per ELF program header in the
 * range PT_LOPROC to PT_HIPROC, for both the ELF being loaded and its
 * interpreter.
 *
 * Return: Zero to proceed with the ELF load, non-zero to fail the ELF load
 *         with that return code.
 */
static inline int arch_elf_pt_proc(struct elfhdr *ehdr,
				   struct elf_phdr *phdr,
				   struct file *elf, bool is_interp,
				   struct arch_elf_state *state)
{
	/* Dummy implementation, always proceed */
	return 0;
}

/**
 * arch_check_elf() - check a PT_LOPROC..PT_HIPROC ELF program header
 * @ehdr:	The main ELF header
 * @has_interp:	True if the ELF has an interpreter, else false.
 * @state:	Architecture-specific state preserved throughout the process
 *		of loading the ELF.
 *
 * Provides a final opportunity for architecture code to reject the loading
 * of the ELF & cause an exec syscall to return an error. This is called after
 * all program headers to be checked by arch_elf_pt_proc have been.
 *
 * Return: Zero to proceed with the ELF load, non-zero to fail the ELF load
 *         with that return code.
 */
static inline int arch_check_elf(struct elfhdr *ehdr, bool has_interp,
				 struct arch_elf_state *state)
{
	/* Dummy implementation, always proceed */
	return 0;
}

#endif /* !CONFIG_ARCH_BINFMT_ELF_STATE */
510

Linus Torvalds's avatar
Linus Torvalds committed
511
512
513
514
515
/* This is much more generalized than the library routine read function,
   so we keep this separate.  Technically the library read function
   is only provided so that we can read a.out libraries that have
   an ELF header */

516
static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
517
		struct file *interpreter, unsigned long *interp_map_addr,
518
		unsigned long no_base, struct elf_phdr *interp_elf_phdata)
Linus Torvalds's avatar
Linus Torvalds committed
519
520
521
522
523
524
{
	struct elf_phdr *eppnt;
	unsigned long load_addr = 0;
	int load_addr_set = 0;
	unsigned long last_bss = 0, elf_bss = 0;
	unsigned long error = ~0UL;
525
	unsigned long total_size;
526
	int i;
Linus Torvalds's avatar
Linus Torvalds committed
527
528
529
530
531
532
533

	/* First of all, some simple consistency checks */
	if (interp_elf_ex->e_type != ET_EXEC &&
	    interp_elf_ex->e_type != ET_DYN)
		goto out;
	if (!elf_check_arch(interp_elf_ex))
		goto out;
Al Viro's avatar
Al Viro committed
534
	if (!interpreter->f_op->mmap)
Linus Torvalds's avatar
Linus Torvalds committed
535
536
		goto out;

537
538
	total_size = total_mapping_size(interp_elf_phdata,
					interp_elf_ex->e_phnum);
539
540
	if (!total_size) {
		error = -EINVAL;
541
		goto out;
542
543
	}

544
	eppnt = interp_elf_phdata;
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
	for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
		if (eppnt->p_type == PT_LOAD) {
			int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
			int elf_prot = 0;
			unsigned long vaddr = 0;
			unsigned long k, map_addr;

			if (eppnt->p_flags & PF_R)
		    		elf_prot = PROT_READ;
			if (eppnt->p_flags & PF_W)
				elf_prot |= PROT_WRITE;
			if (eppnt->p_flags & PF_X)
				elf_prot |= PROT_EXEC;
			vaddr = eppnt->p_vaddr;
			if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
				elf_type |= MAP_FIXED;
561
562
			else if (no_base && interp_elf_ex->e_type == ET_DYN)
				load_addr = -vaddr;
563
564

			map_addr = elf_map(interpreter, load_addr + vaddr,
565
					eppnt, elf_prot, elf_type, total_size);
566
567
568
			total_size = 0;
			if (!*interp_map_addr)
				*interp_map_addr = map_addr;
569
570
			error = map_addr;
			if (BAD_ADDR(map_addr))
571
				goto out;
572
573
574
575
576
577
578
579
580
581
582
583
584

			if (!load_addr_set &&
			    interp_elf_ex->e_type == ET_DYN) {
				load_addr = map_addr - ELF_PAGESTART(vaddr);
				load_addr_set = 1;
			}

			/*
			 * Check to see if the section's size will overflow the
			 * allowed task size. Note that p_filesz must always be
			 * <= p_memsize so it's only necessary to check p_memsz.
			 */
			k = load_addr + eppnt->p_vaddr;
585
			if (BAD_ADDR(k) ||
586
587
588
589
			    eppnt->p_filesz > eppnt->p_memsz ||
			    eppnt->p_memsz > TASK_SIZE ||
			    TASK_SIZE - eppnt->p_memsz < k) {
				error = -ENOMEM;
590
				goto out;
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
			}

			/*
			 * Find the end of the file mapping for this phdr, and
			 * keep track of the largest address we see for this.
			 */
			k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
			if (k > elf_bss)
				elf_bss = k;

			/*
			 * Do the same thing for the memory mapping - between
			 * elf_bss and last_bss is the bss section.
			 */
			k = load_addr + eppnt->p_memsz + eppnt->p_vaddr;
			if (k > last_bss)
				last_bss = k;
		}
Linus Torvalds's avatar
Linus Torvalds committed
609
610
	}

611
612
613
614
615
616
617
618
619
	if (last_bss > elf_bss) {
		/*
		 * Now fill out the bss section.  First pad the last page up
		 * to the page boundary, and then perform a mmap to make sure
		 * that there are zero-mapped pages up to and including the
		 * last bss page.
		 */
		if (padzero(elf_bss)) {
			error = -EFAULT;
620
			goto out;
621
		}
Linus Torvalds's avatar
Linus Torvalds committed
622

623
624
		/* What we have mapped so far */
		elf_bss = ELF_PAGESTART(elf_bss + ELF_MIN_ALIGN - 1);
Linus Torvalds's avatar
Linus Torvalds committed
625

626
		/* Map the last of the bss segment */
627
		error = vm_brk(elf_bss, last_bss - elf_bss);
Linus Torvalds's avatar
Linus Torvalds committed
628
		if (BAD_ADDR(error))
629
			goto out;
Linus Torvalds's avatar
Linus Torvalds committed
630
631
	}

632
	error = load_addr;
Linus Torvalds's avatar
Linus Torvalds committed
633
634
635
636
637
638
639
640
641
out:
	return error;
}

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

642
#ifndef STACK_RND_MASK
643
#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))	/* 8MB of VA */
644
#endif
Linus Torvalds's avatar
Linus Torvalds committed
645
646
647

static unsigned long randomize_stack_top(unsigned long stack_top)
{
648
	unsigned long random_variable = 0;
Linus Torvalds's avatar
Linus Torvalds committed
649

650
651
	if ((current->flags & PF_RANDOMIZE) &&
		!(current->personality & ADDR_NO_RANDOMIZE)) {
652
653
		random_variable = (unsigned long) get_random_int();
		random_variable &= STACK_RND_MASK;
654
655
		random_variable <<= PAGE_SHIFT;
	}
Linus Torvalds's avatar
Linus Torvalds committed
656
#ifdef CONFIG_STACK_GROWSUP
657
	return PAGE_ALIGN(stack_top) + random_variable;
Linus Torvalds's avatar
Linus Torvalds committed
658
#else
659
	return PAGE_ALIGN(stack_top) - random_variable;
Linus Torvalds's avatar
Linus Torvalds committed
660
661
662
#endif
}

663
static int load_elf_binary(struct linux_binprm *bprm)
Linus Torvalds's avatar
Linus Torvalds committed
664
665
666
667
668
669
{
	struct file *interpreter = NULL; /* to shut gcc up */
 	unsigned long load_addr = 0, load_bias = 0;
	int load_addr_set = 0;
	char * elf_interpreter = NULL;
	unsigned long error;
670
	struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL;
Linus Torvalds's avatar
Linus Torvalds committed
671
672
	unsigned long elf_bss, elf_brk;
	int retval, i;
673
674
	unsigned long elf_entry;
	unsigned long interp_load_addr = 0;
Linus Torvalds's avatar
Linus Torvalds committed
675
	unsigned long start_code, end_code, start_data, end_data;
676
	unsigned long reloc_func_desc __maybe_unused = 0;
677
	int executable_stack = EXSTACK_DEFAULT;
678
	struct pt_regs *regs = current_pt_regs();
Linus Torvalds's avatar
Linus Torvalds committed
679
680
681
682
	struct {
		struct elfhdr elf_ex;
		struct elfhdr interp_elf_ex;
	} *loc;
683
	struct arch_elf_state arch_state = INIT_ARCH_ELF_STATE;
Linus Torvalds's avatar
Linus Torvalds committed
684
685
686
687
688
689
690
691

	loc = kmalloc(sizeof(*loc), GFP_KERNEL);
	if (!loc) {
		retval = -ENOMEM;
		goto out_ret;
	}
	
	/* Get the exec-header */
692
	loc->elf_ex = *((struct elfhdr *)bprm->buf);
Linus Torvalds's avatar
Linus Torvalds committed
693
694
695
696
697
698
699
700
701
702

	retval = -ENOEXEC;
	/* First of all, some simple consistency checks */
	if (memcmp(loc->elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
		goto out;

	if (loc->elf_ex.e_type != ET_EXEC && loc->elf_ex.e_type != ET_DYN)
		goto out;
	if (!elf_check_arch(&loc->elf_ex))
		goto out;
Al Viro's avatar
Al Viro committed
703
	if (!bprm->file->f_op->mmap)
Linus Torvalds's avatar
Linus Torvalds committed
704
705
		goto out;

706
	elf_phdata = load_elf_phdrs(&loc->elf_ex, bprm->file);
Linus Torvalds's avatar
Linus Torvalds committed
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
	if (!elf_phdata)
		goto out;

	elf_ppnt = elf_phdata;
	elf_bss = 0;
	elf_brk = 0;

	start_code = ~0UL;
	end_code = 0;
	start_data = 0;
	end_data = 0;

	for (i = 0; i < loc->elf_ex.e_phnum; i++) {
		if (elf_ppnt->p_type == PT_INTERP) {
			/* This is the program interpreter used for
			 * shared libraries - for now assume that this
			 * is an a.out format binary
			 */
			retval = -ENOEXEC;
			if (elf_ppnt->p_filesz > PATH_MAX || 
			    elf_ppnt->p_filesz < 2)
728
				goto out_free_ph;
Linus Torvalds's avatar
Linus Torvalds committed
729
730

			retval = -ENOMEM;
731
			elf_interpreter = kmalloc(elf_ppnt->p_filesz,
732
						  GFP_KERNEL);
Linus Torvalds's avatar
Linus Torvalds committed
733
			if (!elf_interpreter)
734
				goto out_free_ph;
Linus Torvalds's avatar
Linus Torvalds committed
735
736

			retval = kernel_read(bprm->file, elf_ppnt->p_offset,
737
738
					     elf_interpreter,
					     elf_ppnt->p_filesz);
Linus Torvalds's avatar
Linus Torvalds committed
739
740
741
742
743
744
745
746
747
748
749
750
751
752
			if (retval != elf_ppnt->p_filesz) {
				if (retval >= 0)
					retval = -EIO;
				goto out_free_interp;
			}
			/* make sure path is NULL terminated */
			retval = -ENOEXEC;
			if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
				goto out_free_interp;

			interpreter = open_exec(elf_interpreter);
			retval = PTR_ERR(interpreter);
			if (IS_ERR(interpreter))
				goto out_free_interp;
753
754
755
756
757
758

			/*
			 * If the binary is not readable then enforce
			 * mm->dumpable = 0 regardless of the interpreter's
			 * permissions.
			 */
759
			would_dump(bprm, interpreter);
760

761
762
			retval = kernel_read(interpreter, 0, bprm->buf,
					     BINPRM_BUF_SIZE);
Linus Torvalds's avatar
Linus Torvalds committed
763
764
765
766
767
768
769
			if (retval != BINPRM_BUF_SIZE) {
				if (retval >= 0)
					retval = -EIO;
				goto out_free_dentry;
			}

			/* Get the exec headers */
770
			loc->interp_elf_ex = *((struct elfhdr *)bprm->buf);
Linus Torvalds's avatar
Linus Torvalds committed
771
772
773
774
775
776
777
			break;
		}
		elf_ppnt++;
	}

	elf_ppnt = elf_phdata;
	for (i = 0; i < loc->elf_ex.e_phnum; i++, elf_ppnt++)
778
779
		switch (elf_ppnt->p_type) {
		case PT_GNU_STACK:
Linus Torvalds's avatar
Linus Torvalds committed
780
781
782
783
784
			if (elf_ppnt->p_flags & PF_X)
				executable_stack = EXSTACK_ENABLE_X;
			else
				executable_stack = EXSTACK_DISABLE_X;
			break;
785
786
787
788
789
790
791
792

		case PT_LOPROC ... PT_HIPROC:
			retval = arch_elf_pt_proc(&loc->elf_ex, elf_ppnt,
						  bprm->file, false,
						  &arch_state);
			if (retval)
				goto out_free_dentry;
			break;
Linus Torvalds's avatar
Linus Torvalds committed
793
794
795
796
797
		}

	/* Some simple consistency checks for the interpreter */
	if (elf_interpreter) {
		retval = -ELIBBAD;
798
799
		/* Not an ELF interpreter */
		if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
Linus Torvalds's avatar
Linus Torvalds committed
800
801
			goto out_free_dentry;
		/* Verify the interpreter has a valid arch */
802
		if (!elf_check_arch(&loc->interp_elf_ex))
Linus Torvalds's avatar
Linus Torvalds committed
803
			goto out_free_dentry;
804
805
806
807
808
809

		/* Load the interpreter program headers */
		interp_elf_phdata = load_elf_phdrs(&loc->interp_elf_ex,
						   interpreter);
		if (!interp_elf_phdata)
			goto out_free_dentry;
810
811
812
813
814
815
816
817
818
819
820
821
822

		/* Pass PT_LOPROC..PT_HIPROC headers to arch code */
		elf_ppnt = interp_elf_phdata;
		for (i = 0; i < loc->interp_elf_ex.e_phnum; i++, elf_ppnt++)
			switch (elf_ppnt->p_type) {
			case PT_LOPROC ... PT_HIPROC:
				retval = arch_elf_pt_proc(&loc->interp_elf_ex,
							  elf_ppnt, interpreter,
							  true, &arch_state);
				if (retval)
					goto out_free_dentry;
				break;
			}
Linus Torvalds's avatar
Linus Torvalds committed
823
824
	}

825
826
827
828
829
830
831
832
833
	/*
	 * Allow arch code to reject the ELF at this point, whilst it's
	 * still possible to return an error to the code that invoked
	 * the exec syscall.
	 */
	retval = arch_check_elf(&loc->elf_ex, !!interpreter, &arch_state);
	if (retval)
		goto out_free_dentry;

Linus Torvalds's avatar
Linus Torvalds committed
834
835
836
837
838
839
840
	/* Flush all traces of the currently running executable */
	retval = flush_old_exec(bprm);
	if (retval)
		goto out_free_dentry;

	/* Do this immediately, since STACK_TOP as used in setup_arg_pages
	   may depend on the personality.  */
841
	SET_PERSONALITY2(loc->elf_ex, &arch_state);
Linus Torvalds's avatar
Linus Torvalds committed
842
843
844
	if (elf_read_implies_exec(loc->elf_ex, executable_stack))
		current->personality |= READ_IMPLIES_EXEC;

845
	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
Linus Torvalds's avatar
Linus Torvalds committed
846
		current->flags |= PF_RANDOMIZE;
847
848

	setup_new_exec(bprm);
Linus Torvalds's avatar
Linus Torvalds committed
849
850
851
852
853

	/* Do this so that we can load the interpreter, if need be.  We will
	   change some of these later */
	retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
				 executable_stack);
854
	if (retval < 0)
Linus Torvalds's avatar
Linus Torvalds committed
855
856
857
858
		goto out_free_dentry;
	
	current->mm->start_stack = bprm->p;

859
	/* Now we do a little grungy work by mmapping the ELF image into
860
	   the correct location in memory. */
861
862
	for(i = 0, elf_ppnt = elf_phdata;
	    i < loc->elf_ex.e_phnum; i++, elf_ppnt++) {
Linus Torvalds's avatar
Linus Torvalds committed
863
864
		int elf_prot = 0, elf_flags;
		unsigned long k, vaddr;
865
		unsigned long total_size = 0;
Linus Torvalds's avatar
Linus Torvalds committed
866
867
868
869
870
871
872
873
874
875

		if (elf_ppnt->p_type != PT_LOAD)
			continue;

		if (unlikely (elf_brk > elf_bss)) {
			unsigned long nbyte;
	            
			/* There was a PT_LOAD segment with p_memsz > p_filesz
			   before this one. Map anonymous pages, if needed,
			   and clear the area.  */
Mikael Pettersson's avatar
Mikael Pettersson committed
876
877
			retval = set_brk(elf_bss + load_bias,
					 elf_brk + load_bias);
878
			if (retval)
Linus Torvalds's avatar
Linus Torvalds committed
879
880
881
882
883
884
885
886
887
888
				goto out_free_dentry;
			nbyte = ELF_PAGEOFFSET(elf_bss);
			if (nbyte) {
				nbyte = ELF_MIN_ALIGN - nbyte;
				if (nbyte > elf_brk - elf_bss)
					nbyte = elf_brk - elf_bss;
				if (clear_user((void __user *)elf_bss +
							load_bias, nbyte)) {
					/*
					 * This bss-zeroing can fail if the ELF
889
					 * file specifies odd protections. So
Linus Torvalds's avatar
Linus Torvalds committed
890
891
892
893
894
895
					 * we don't check the return value
					 */
				}
			}
		}

896
897
898
899
900
901
		if (elf_ppnt->p_flags & PF_R)
			elf_prot |= PROT_READ;
		if (elf_ppnt->p_flags & PF_W)
			elf_prot |= PROT_WRITE;
		if (elf_ppnt->p_flags & PF_X)
			elf_prot |= PROT_EXEC;
Linus Torvalds's avatar
Linus Torvalds committed
902

903
		elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE;
Linus Torvalds's avatar
Linus Torvalds committed
904
905
906
907
908

		vaddr = elf_ppnt->p_vaddr;
		if (loc->elf_ex.e_type == ET_EXEC || load_addr_set) {
			elf_flags |= MAP_FIXED;
		} else if (loc->elf_ex.e_type == ET_DYN) {
909
910
911
912
			/* Try and get dynamic programs out of the way of the
			 * default mmap base, as well as whatever program they
			 * might try to exec.  This is because the brk will
			 * follow the loader, and is not movable.  */
913
#ifdef CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE
914
			/* Memory randomization might have been switched off
915
916
			 * in runtime via sysctl or explicit setting of
			 * personality flags.
917
918
919
920
921
922
923
924
			 * If that is the case, retain the original non-zero
			 * load_bias value in order to establish proper
			 * non-randomized mappings.
			 */
			if (current->flags & PF_RANDOMIZE)
				load_bias = 0;
			else
				load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
925
#else
926
			load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
927
#endif
928
929
930
931
932
933
			total_size = total_mapping_size(elf_phdata,
							loc->elf_ex.e_phnum);
			if (!total_size) {
				error = -EINVAL;
				goto out_free_dentry;
			}
Linus Torvalds's avatar
Linus Torvalds committed
934
935
		}

936
		error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
937
				elf_prot, elf_flags, total_size);
Linus Torvalds's avatar
Linus Torvalds committed
938
		if (BAD_ADDR(error)) {
939
940
			retval = IS_ERR((void *)error) ?
				PTR_ERR((void*)error) : -EINVAL;
Linus Torvalds's avatar
Linus Torvalds committed
941
942
943
944
945
946
947
948
949
950
951
952
953
954
			goto out_free_dentry;
		}

		if (!load_addr_set) {
			load_addr_set = 1;
			load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset);
			if (loc->elf_ex.e_type == ET_DYN) {
				load_bias += error -
				             ELF_PAGESTART(load_bias + vaddr);
				load_addr += load_bias;
				reloc_func_desc = load_bias;
			}
		}
		k = elf_ppnt->p_vaddr;
955
956
957
958
		if (k < start_code)
			start_code = k;
		if (start_data < k)
			start_data = k;
Linus Torvalds's avatar
Linus Torvalds committed
959
960
961
962
963
964

		/*
		 * Check to see if the section's size will overflow the
		 * allowed task size. Note that p_filesz must always be
		 * <= p_memsz so it is only necessary to check p_memsz.
		 */
965
		if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
Linus Torvalds's avatar
Linus Torvalds committed
966
967
		    elf_ppnt->p_memsz > TASK_SIZE ||
		    TASK_SIZE - elf_ppnt->p_memsz < k) {
968
			/* set_brk can never work. Avoid overflows. */
969
			retval = -EINVAL;
Linus Torvalds's avatar
Linus Torvalds committed
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
			goto out_free_dentry;
		}

		k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;

		if (k > elf_bss)
			elf_bss = k;
		if ((elf_ppnt->p_flags & PF_X) && end_code < k)
			end_code = k;
		if (end_data < k)
			end_data = k;
		k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
		if (k > elf_brk)
			elf_brk = k;
	}

	loc->elf_ex.e_entry += load_bias;
	elf_bss += load_bias;
	elf_brk += load_bias;
	start_code += load_bias;
	end_code += load_bias;
	start_data += load_bias;
	end_data += load_bias;

	/* Calling set_brk effectively mmaps the pages that we need
	 * for the bss and break sections.  We must do this before
	 * mapping in the interpreter, to make sure it doesn't wind
	 * up getting placed where the bss needs to go.
	 */
	retval = set_brk(elf_bss, elf_brk);
1000
	if (retval)
Linus Torvalds's avatar
Linus Torvalds committed
1001
		goto out_free_dentry;
1002
	if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) {
Linus Torvalds's avatar
Linus Torvalds committed
1003
1004
1005
1006
1007
		retval = -EFAULT; /* Nobody gets to see this, but.. */
		goto out_free_dentry;
	}

	if (elf_interpreter) {
Alan Cox's avatar
Alan Cox committed
1008
		unsigned long interp_map_addr = 0;
1009
1010
1011
1012

		elf_entry = load_elf_interp(&loc->interp_elf_ex,
					    interpreter,
					    &interp_map_addr,
1013
					    load_bias, interp_elf_phdata);
1014
1015
1016
1017
1018
1019
1020
		if (!IS_ERR((void *)elf_entry)) {
			/*
			 * load_elf_interp() returns relocation
			 * adjustment
			 */
			interp_load_addr = elf_entry;
			elf_entry += loc->interp_elf_ex.e_entry;
1021
		}
Linus Torvalds's avatar
Linus Torvalds committed
1022
		if (BAD_ADDR(elf_entry)) {
1023
1024
			retval = IS_ERR((void *)elf_entry) ?
					(int)elf_entry : -EINVAL;
Linus Torvalds's avatar
Linus Torvalds committed
1025
1026
1027
1028
1029
1030
1031
1032
1033
			goto out_free_dentry;
		}
		reloc_func_desc = interp_load_addr;

		allow_write_access(interpreter);
		fput(interpreter);
		kfree(elf_interpreter);
	} else {
		elf_entry = loc->elf_ex.e_entry;
1034
		if (BAD_ADDR(elf_entry)) {
1035
			retval = -EINVAL;
1036
1037
			goto out_free_dentry;
		}
Linus Torvalds's avatar
Linus Torvalds committed
1038
1039
	}

1040
	kfree(interp_elf_phdata);
Linus Torvalds's avatar
Linus Torvalds committed
1041
1042
1043
1044
	kfree(elf_phdata);

	set_binfmt(&elf_format);

1045
#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
1046
	retval = arch_setup_additional_pages(bprm, !!elf_interpreter);
1047
	if (retval < 0)
1048
		goto out;
1049
1050
#endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */

1051
	install_exec_creds(bprm);
1052
	retval = create_elf_tables(bprm, &loc->elf_ex,
1053
			  load_addr, interp_load_addr);
1054
	if (retval < 0)
1055
		goto out;
Linus Torvalds's avatar
Linus Torvalds committed
1056
1057
1058
1059
1060
1061
1062
	/* N.B. passed_fileno might not be initialized? */
	current->mm->end_code = end_code;
	current->mm->start_code = start_code;
	current->mm->start_data = start_data;
	current->mm->end_data = end_data;
	current->mm->start_stack = bprm->p;

Jiri Kosina's avatar
Jiri Kosina committed
1063
#ifdef arch_randomize_brk
1064
	if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1)) {
Jiri Kosina's avatar
Jiri Kosina committed
1065
1066
		current->mm->brk = current->mm->start_brk =
			arch_randomize_brk(current->mm);
1067
1068
1069
1070
#ifdef CONFIG_COMPAT_BRK
		current->brk_randomized = 1;
#endif
	}
Jiri Kosina's avatar
Jiri Kosina committed
1071
1072
#endif

Linus Torvalds's avatar
Linus Torvalds committed
1073
1074
1075
1076
	if (current->personality & MMAP_PAGE_ZERO) {
		/* Why this, you ask???  Well SVr4 maps page 0 as read-only,
		   and some applications "depend" upon this behavior.
		   Since we do not have the power to recompile these, we
1077
		   emulate the SVr4 behavior. Sigh. */
1078
		error = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
Linus Torvalds's avatar
Linus Torvalds committed
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
				MAP_FIXED | MAP_PRIVATE, 0);
	}

#ifdef ELF_PLAT_INIT
	/*
	 * The ABI may specify that certain registers be set up in special
	 * ways (on i386 %edx is the address of a DT_FINI function, for
	 * example.  In addition, it may also specify (eg, PowerPC64 ELF)
	 * that the e_entry field is the address of the function descriptor
	 * for the startup routine, rather than the address of the startup
	 * routine itself.  This macro performs whatever initialization to
	 * the regs structure is required as well as any relocations to the
	 * function descriptor entries when executing dynamically links apps.
	 */
	ELF_PLAT_INIT(regs, reloc_func_desc);
#endif

	start_thread(regs, elf_entry, bprm->p);
	retval = 0;
out:
	kfree(loc);
out_ret:
	return retval;

	/* error cleanup */
out_free_dentry:
1105
	kfree(interp_elf_phdata);
Linus Torvalds's avatar
Linus Torvalds committed
1106
1107
1108
1109
	allow_write_access(interpreter);
	if (interpreter)
		fput(interpreter);
out_free_interp:
Jesper Juhl's avatar
Jesper Juhl committed
1110
	kfree(elf_interpreter);
Linus Torvalds's avatar
Linus Torvalds committed
1111
1112
1113
1114
1115
out_free_ph:
	kfree(elf_phdata);
	goto out;
}

1116
#ifdef CONFIG_USELIB
Linus Torvalds's avatar
Linus Torvalds committed
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
/* This is really simpleminded and specialized - we are loading an
   a.out library that is given an ELF header. */
static int load_elf_library(struct file *file)
{
	struct elf_phdr *elf_phdata;
	struct elf_phdr *eppnt;
	unsigned long elf_bss, bss, len;
	int retval, error, i, j;
	struct elfhdr elf_ex;

	error = -ENOEXEC;
1128
	retval = kernel_read(file, 0, (char *)&elf_ex, sizeof(elf_ex));
Linus Torvalds's avatar
Linus Torvalds committed
1129
1130
1131
1132
1133
1134
1135
1136
	if (retval != sizeof(elf_ex))
		goto out;

	if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
		goto out;

	/* First of all, some simple consistency checks */
	if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
Al Viro's avatar
Al Viro committed
1137
	    !elf_check_arch(&elf_ex) || !file->f_op->mmap)
Linus Torvalds's avatar
Linus Torvalds committed
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
		goto out;

	/* Now read in all of the header information */

	j = sizeof(struct elf_phdr) * elf_ex.e_phnum;
	/* j < ELF_MIN_ALIGN because elf_ex.e_phnum <= 2 */

	error = -ENOMEM;
	elf_phdata = kmalloc(j, GFP_KERNEL);
	if (!elf_phdata)
		goto out;

	eppnt = elf_phdata;
	error = -ENOEXEC;
	retval = kernel_read(file, elf_ex.e_phoff, (char *)eppnt, j);
	if (retval != j)
		goto out_free_ph;

	for (j = 0, i = 0; i<elf_ex.e_phnum; i++)
		if ((eppnt + i)->p_type == PT_LOAD)
			j++;
	if (j != 1)
		goto out_free_ph;

	while (eppnt->p_type != PT_LOAD)
		eppnt++;

	/* Now use mmap to map the library into memory. */
1166
	error = vm_mmap(file,
Linus Torvalds's avatar
Linus Torvalds committed
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
			ELF_PAGESTART(eppnt->p_vaddr),
			(eppnt->p_filesz +
			 ELF_PAGEOFFSET(eppnt->p_vaddr)),
			PROT_READ | PROT_WRITE | PROT_EXEC,
			MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
			(eppnt->p_offset -
			 ELF_PAGEOFFSET(eppnt->p_vaddr)));
	if (error != ELF_PAGESTART(eppnt->p_vaddr))
		goto out_free_ph;

	elf_bss = eppnt->p_vaddr + eppnt->p_filesz;
	if (padzero(elf_bss)) {
		error = -EFAULT;
		goto out_free_ph;
	}

1183
1184
	len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr +
			    ELF_MIN_ALIGN - 1);
Linus Torvalds's avatar
Linus Torvalds committed
1185
	bss = eppnt->p_memsz + eppnt->p_vaddr;
1186
1187
	if (bss > len)
		vm_brk(len, bss - len);
Linus Torvalds's avatar
Linus Torvalds committed
1188
1189
1190
1191
1192
1193
1194
	error = 0;

out_free_ph:
	kfree(elf_phdata);
out:
	return error;
}
1195
#endif /* #ifdef CONFIG_USELIB */
Linus Torvalds's avatar
Linus Torvalds committed
1196

1197
#ifdef CONFIG_ELF_CORE
Linus Torvalds's avatar
Linus Torvalds committed
1198
1199
1200
1201
1202
1203
1204
/*
 * ELF core dumper
 *
 * Modelled on fs/exec.c:aout_core_dump()
 * Jeremy Fitzhardinge <jeremy@sw.oz.au>
 */

1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
/*
 * The purpose of always_dump_vma() is to make sure that special kernel mappings
 * that are useful for post-mortem analysis are included in every core dump.
 * In that way we ensure that the core dump is fully interpretable later
 * without matching up the same kernel and hardware config to see what PC values
 * meant. These special mappings include - vDSO, vsyscall, and other
 * architecture specific mappings
 */
static bool always_dump_vma(struct vm_area_struct *vma)
{
	/* Any vsyscall mappings? */
	if (vma == get_gate_vma(vma->vm_mm))
		return true;
1218
1219
1220
1221
1222
1223
1224
1225

	/*
	 * Assume that all vmas with a .name op should always be dumped.
	 * If this changes, a new vm_ops field can easily be added.
	 */
	if (vma->vm_ops && vma->vm_ops->name && vma->vm_ops->name(vma))
		return true;

1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
	/*
	 * arch_vma_name() returns non-NULL for special architecture mappings,
	 * such as vDSO sections.
	 */
	if (arch_vma_name(vma))
		return true;

	return false;
}

Linus Torvalds's avatar
Linus Torvalds committed
1236
/*
Roland McGrath's avatar
Roland McGrath committed
1237
 * Decide what to dump of a segment, part, all or none.
Linus Torvalds's avatar
Linus Torvalds committed
1238
 */
Roland McGrath's avatar
Roland McGrath committed
1239
1240
static unsigned long vma_dump_size(struct vm_area_struct *vma,
				   unsigned long mm_flags)
Linus Torvalds's avatar
Linus Torvalds committed
1241
{
1242
1243
#define FILTER(type)	(mm_flags & (1UL << MMF_DUMP_##type))

1244
1245
	/* always dump the vdso and vsyscall sections */
	if (always_dump_vma(vma))
Roland McGrath's avatar
Roland McGrath committed
1246
		goto whole;
Roland McGrath's avatar
Roland McGrath committed
1247

1248
	if (vma->vm_flags & VM_DONTDUMP)
1249
1250
		return 0;

1251
1252
1253
1254
1255
1256
	/* Hugetlb memory check */
	if (vma->vm_flags & VM_HUGETLB) {
		if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
			goto whole;
		if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
			goto whole;
1257
		return 0;
1258
1259
	}

Linus Torvalds's avatar
Linus Torvalds committed
1260
	/* Do not dump I/O mapped devices or special mappings */
1261
	if (vma->vm_flags & VM_IO)
Linus Torvalds's avatar
Linus Torvalds committed
1262
1263
		return 0;

1264
1265
	/* By default, dump shared memory if mapped from an anonymous file. */
	if (vma->vm_flags & VM_SHARED) {
Al Viro's avatar
Al Viro committed
1266
		if (file_inode(vma->vm_file)->i_nlink == 0 ?
Roland McGrath's avatar
Roland McGrath committed
1267
1268
1269
		    FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
			goto whole;
		return 0;
1270
	}
Linus Torvalds's avatar
Linus Torvalds committed
1271

Roland McGrath's avatar
Roland McGrath committed
1272
1273
1274
1275
1276
	/* Dump segments that have been written to.  */
	if (vma->anon_vma && FILTER(ANON_PRIVATE))
		goto whole;
	if (vma->vm_file == NULL)
		return 0;
Linus Torvalds's avatar
Linus Torvalds committed
1277

Roland McGrath's avatar
Roland McGrath committed
1278
1279
1280
1281
1282
1283
1284
1285
	if (FILTER(MAPPED_PRIVATE))
		goto whole;

	/*
	 * If this looks like the beginning of a DSO or executable mapping,
	 * check for an ELF header.  If we find one, dump the first page to
	 * aid in determining what was mapped here.
	 */
1286
1287
	if (FILTER(ELF_HEADERS) &&
	    vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
Roland McGrath's avatar
Roland McGrath committed
1288
1289
		u32 __user *header = (u32 __user *) vma->vm_start;
		u32 word;
1290
		mm_segment_t fs = get_fs();
Roland McGrath's avatar
Roland McGrath committed
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
		/*
		 * Doing it this way gets the constant folded by GCC.
		 */
		union {
			u32 cmp;
			char elfmag[SELFMAG];
		} magic;
		BUILD_BUG_ON(SELFMAG != sizeof word);
		magic.elfmag[EI_MAG0] = ELFMAG0;
		magic.elfmag[EI_MAG1] = ELFMAG1;
		magic.elfmag[EI_MAG2] = ELFMAG2;
		magic.elfmag[EI_MAG3] = ELFMAG3;
1303
1304
1305
1306
1307
1308
1309
1310
1311
		/*
		 * Switch to the user "segment" for get_user(),
		 * then put back what elf_core_dump() had in place.
		 */
		set_fs(USER_DS);
		if (unlikely(get_user(word, header)))
			word = 0;
		set_fs(fs);
		if (word == magic.cmp)
Roland McGrath's avatar
Roland McGrath committed
1312
1313
1314
1315
1316
1317
1318
1319
1320
			return PAGE_SIZE;
	}

#undef	FILTER

	return 0;

whole:
	return vma->vm_end - vma->vm_start;
Linus Torvalds's avatar
Linus Torvalds committed
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
}

/* An ELF note in memory */
struct memelfnote
{
	const char *name;
	int type;
	unsigned int datasz;
	void *data;
};

static int notesize(struct memelfnote *en)
{
	int sz;

	sz = sizeof(struct elf_note);
	sz += roundup(strlen(en->name) + 1, 4);
	sz += roundup(en->datasz, 4);

	return sz;
}

Al Viro's avatar
Al Viro committed
1343
static int writenote(struct memelfnote *men, struct coredump_params *cprm)
1344
1345
{
	struct elf_note en;
Linus Torvalds's avatar
Linus Torvalds committed
1346
1347
1348
1349
	en.n_namesz = strlen(men->name) + 1;
	en.n_descsz = men->datasz;
	en.n_type = men->type;

Al Viro's avatar
Al Viro committed
1350
	return dump_emit(cprm, &en, sizeof(en)) &&
Al Viro's avatar
Al Viro committed
1351
1352
	    dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) &&
	    dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4);
Linus Torvalds's avatar
Linus Torvalds committed
1353
1354
}

Roland McGrath's avatar
Roland McGrath committed
1355
static void fill_elf_header(struct elfhdr *elf, int segs,
1356
			    u16 machine, u32 flags)
Linus Torvalds's avatar
Linus Torvalds committed
1357
{
1358
1359
	memset(elf, 0, sizeof(*elf));

Linus Torvalds's avatar
Linus Torvalds committed
1360
1361
1362
1363
1364
1365
1366
	memcpy(elf->e_ident, ELFMAG, SELFMAG);
	elf->e_ident[EI_CLASS] = ELF_CLASS;
	elf->e_ident[EI_DATA] = ELF_DATA;
	elf->e_ident[EI_VERSION] = EV_CURRENT;
	elf->e_ident[EI_OSABI] = ELF_OSABI;

	elf->e_type = ET_CORE;
Roland McGrath's avatar
Roland McGrath committed
1367
	elf->e_machine = machine;
Linus Torvalds's avatar
Linus Torvalds committed
1368
1369
	elf->e_version = EV_CURRENT;
	elf->e_phoff = sizeof(struct elfhdr);
Roland McGrath's avatar
Roland McGrath committed
1370
	elf->e_flags = flags;
Linus Torvalds's avatar
Linus Torvalds committed
1371
1372
1373
	elf->e_ehsize = sizeof(struct elfhdr);
	elf->e_phentsize = sizeof(struct elf_phdr);
	elf->e_phnum = segs;
1374

Linus Torvalds's avatar
Linus Torvalds committed
1375
1376
1377
	return;
}

1378
static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
Linus Torvalds's avatar
Linus Torvalds committed
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
{
	phdr->p_type = PT_NOTE;
	phdr->p_offset = offset;
	phdr->p_vaddr = 0;
	phdr->p_paddr = 0;
	phdr->p_filesz = sz;
	phdr->p_memsz = 0;
	phdr->p_flags = 0;
	phdr->p_align = 0;
	return;
}

static void fill_note(struct memelfnote *note, const char *name, int type, 
		unsigned int sz, void *data)
{
	note->name = name;
	note->type = type;
	note->datasz = sz;
	note->data = data;
	return;
}

/*
1402
1403
 * fill up all the fields in prstatus from the given task struct, except
 * registers which need to be filled up separately.
Linus Torvalds's avatar
Linus Torvalds committed
1404
1405
 */
static void fill_prstatus(struct elf_prstatus *prstatus,
1406
		struct task_struct *p, long signr)
Linus Torvalds's avatar
Linus Torvalds committed
1407
1408
1409
1410
{
	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
	prstatus->pr_sigpend = p->pending.signal.sig[0];
	prstatus->pr_sighold = p->blocked.sig[0];
1411
1412
1413
	rcu_read_lock();
	prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
	rcu_read_unlock();
1414
1415
1416
	prstatus->pr_pid = task_pid_vnr(p);
	prstatus->pr_pgrp = task_pgrp_vnr(p);
	prstatus->pr_sid = task_session_vnr(p);
Linus Torvalds's avatar
Linus Torvalds committed
1417
	if (thread_group_leader(p)) {
1418
1419
		struct task_cputime cputime;

Linus Torvalds's avatar
Linus Torvalds committed
1420
		/*
1421
1422
		 * This is the record for the group leader.  It shows the
		 * group-wide total, not its individual thread total.
Linus Torvalds's avatar
Linus Torvalds committed
1423
		 */
1424
1425
1426
		thread_group_cputime(p, &cputime);
		cputime_to_timeval(cputime.utime, &prstatus->pr_utime);
		cputime_to_timeval(cputime.stime, &prstatus->pr_stime);
Linus Torvalds's avatar
Linus Torvalds committed
1427
	} else {
1428
1429
1430
1431
1432
		cputime_t utime, stime;

		task_cputime(p, &utime, &stime);
		cputime_to_timeval(utime, &prstatus->pr_utime);
		cputime_to_timeval(stime, &prstatus->pr_stime);
Linus Torvalds's avatar
Linus Torvalds committed
1433
1434
1435
1436
1437
1438
1439
1440
	}
	cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
	cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);
}

static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
		       struct mm_struct *mm)
{
1441
	const struct cred *cred;
1442
	unsigned int i, len;
Linus Torvalds's avatar
Linus Torvalds committed