binfmt_elf.c 57.3 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
static int load_elf_library(struct file *);
50 51
static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *,
				int, int, unsigned long);
Linus Torvalds's avatar
Linus Torvalds committed
52 53 54 55 56

/*
 * If we don't support core dumping, then supply a NULL so we
 * don't even try.
 */
57
#ifdef CONFIG_ELF_CORE
58
static int elf_core_dump(struct coredump_params *cprm);
Linus Torvalds's avatar
Linus Torvalds committed
59 60 61 62 63
#else
#define elf_core_dump	NULL
#endif

#if ELF_EXEC_PAGESIZE > PAGE_SIZE
64
#define ELF_MIN_ALIGN	ELF_EXEC_PAGESIZE
Linus Torvalds's avatar
Linus Torvalds committed
65
#else
66
#define ELF_MIN_ALIGN	PAGE_SIZE
Linus Torvalds's avatar
Linus Torvalds committed
67 68 69 70 71 72 73 74 75 76 77
#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
78 79 80 81 82
	.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
83 84
};

Andrew Morton's avatar
Andrew Morton committed
85
#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
Linus Torvalds's avatar
Linus Torvalds committed
86 87 88 89 90 91 92

static int set_brk(unsigned long start, unsigned long end)
{
	start = ELF_PAGEALIGN(start);
	end = ELF_PAGEALIGN(end);
	if (end > start) {
		unsigned long addr;
93
		addr = vm_brk(start, end - start);
Linus Torvalds's avatar
Linus Torvalds committed
94 95 96 97 98 99 100 101 102 103
		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
104 105
   be in memory
 */
Linus Torvalds's avatar
Linus Torvalds committed
106 107 108 109 110 111 112 113 114 115 116 117 118
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
119
/* Let's use some macros to make this stack manipulation a little clearer */
Linus Torvalds's avatar
Linus Torvalds committed
120 121 122 123
#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)
124 125 126
#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
127 128 129 130 131 132 133
#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

134 135 136 137 138 139 140 141 142
#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
143
static int
144
create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
145
		unsigned long load_addr, unsigned long interp_load_addr)
Linus Torvalds's avatar
Linus Torvalds committed
146 147 148 149 150 151 152 153
{
	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;
154
	elf_addr_t __user *u_base_platform;
155
	elf_addr_t __user *u_rand_bytes;
Linus Torvalds's avatar
Linus Torvalds committed
156
	const char *k_platform = ELF_PLATFORM;
157
	const char *k_base_platform = ELF_BASE_PLATFORM;
158
	unsigned char k_rand_bytes[16];
Linus Torvalds's avatar
Linus Torvalds committed
159 160 161
	int items;
	elf_addr_t *elf_info;
	int ei_index = 0;
162
	const struct cred *cred = current_cred();
163
	struct vm_area_struct *vma;
Linus Torvalds's avatar
Linus Torvalds committed
164

165 166 167 168 169 170 171 172
	/*
	 * 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
173 174 175 176 177 178 179 180 181 182 183 184 185 186 187
	/*
	 * 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;
	}

188 189 190 191 192 193 194 195 196 197 198 199 200
	/*
	 * 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;
	}

201 202 203 204 205 206 207 208 209
	/*
	 * 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
210
	/* Create the ELF interpreter info */
211
	elf_info = (elf_addr_t *)current->mm->saved_auxv;
212
	/* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */
Linus Torvalds's avatar
Linus Torvalds committed
213
#define NEW_AUX_ENT(id, val) \
214
	do { \
215 216
		elf_info[ei_index++] = id; \
		elf_info[ei_index++] = val; \
217
	} while (0)
Linus Torvalds's avatar
Linus Torvalds committed
218 219 220 221 222

#ifdef ARCH_DLINFO
	/* 
	 * ARCH_DLINFO must come first so PPC can do its special alignment of
	 * AUXV.
223 224
	 * update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT() in
	 * ARCH_DLINFO changes
Linus Torvalds's avatar
Linus Torvalds committed
225 226 227 228 229 230 231
	 */
	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);
232
	NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
Linus Torvalds's avatar
Linus Torvalds committed
233 234 235 236
	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);
237 238 239 240
	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));
241
 	NEW_AUX_ENT(AT_SECURE, security_bprm_secureexec(bprm));
242
	NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
243 244 245
#ifdef ELF_HWCAP2
	NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2);
#endif
246
	NEW_AUX_ENT(AT_EXECFN, bprm->exec);
Linus Torvalds's avatar
Linus Torvalds committed
247
	if (k_platform) {
248
		NEW_AUX_ENT(AT_PLATFORM,
249
			    (elf_addr_t)(unsigned long)u_platform);
Linus Torvalds's avatar
Linus Torvalds committed
250
	}
251 252 253 254
	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
255
	if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
256
		NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
Linus Torvalds's avatar
Linus Torvalds committed
257 258 259 260 261 262 263 264 265 266 267
	}
#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);

268
	items = (argc + 1) + (envc + 1) + 1;
Linus Torvalds's avatar
Linus Torvalds committed
269 270 271 272 273
	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;
274
	bprm->exec = (unsigned long)sp; /* XXX: PARISC HACK */
Linus Torvalds's avatar
Linus Torvalds committed
275 276 277 278
#else
	sp = (elf_addr_t __user *)bprm->p;
#endif

279 280 281 282 283 284 285 286 287

	/*
	 * 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
288 289 290
	/* Now, let's put argc (and argv, envp if appropriate) on the stack */
	if (__put_user(argc, sp++))
		return -EFAULT;
291 292
	argv = sp;
	envp = argv + argc + 1;
Linus Torvalds's avatar
Linus Torvalds committed
293 294

	/* Populate argv and envp */
295
	p = current->mm->arg_end = current->mm->arg_start;
Linus Torvalds's avatar
Linus Torvalds committed
296 297
	while (argc-- > 0) {
		size_t len;
298 299
		if (__put_user((elf_addr_t)p, argv++))
			return -EFAULT;
300 301
		len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
		if (!len || len > MAX_ARG_STRLEN)
302
			return -EINVAL;
Linus Torvalds's avatar
Linus Torvalds committed
303 304 305 306 307 308 309
		p += len;
	}
	if (__put_user(0, argv))
		return -EFAULT;
	current->mm->arg_end = current->mm->env_start = p;
	while (envc-- > 0) {
		size_t len;
310 311
		if (__put_user((elf_addr_t)p, envp++))
			return -EFAULT;
312 313
		len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
		if (!len || len > MAX_ARG_STRLEN)
314
			return -EINVAL;
Linus Torvalds's avatar
Linus Torvalds committed
315 316 317 318 319 320 321 322 323 324 325 326 327
		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;
}

328 329
#ifndef elf_map

Linus Torvalds's avatar
Linus Torvalds committed
330
static unsigned long elf_map(struct file *filep, unsigned long addr,
331 332
		struct elf_phdr *eppnt, int prot, int type,
		unsigned long total_size)
Linus Torvalds's avatar
Linus Torvalds committed
333 334
{
	unsigned long map_addr;
335 336 337 338
	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
339

340 341
	/* mmap() will return -EINVAL if given a zero size, but a
	 * segment with zero filesize is perfectly valid */
342 343 344 345 346 347 348 349 350 351 352 353 354
	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);
355
		map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
356
		if (!BAD_ADDR(map_addr))
357
			vm_munmap(map_addr+size, total_size-size);
358
	} else
359
		map_addr = vm_mmap(filep, addr, size, prot, type, off);
360

Linus Torvalds's avatar
Linus Torvalds committed
361 362 363
	return(map_addr);
}

364 365
#endif /* !elf_map */

366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384
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);
}


Linus Torvalds's avatar
Linus Torvalds committed
385 386 387 388 389
/* 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 */

390
static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
391 392
		struct file *interpreter, unsigned long *interp_map_addr,
		unsigned long no_base)
Linus Torvalds's avatar
Linus Torvalds committed
393 394 395 396 397 398 399
{
	struct elf_phdr *elf_phdata;
	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;
400
	unsigned long total_size;
Linus Torvalds's avatar
Linus Torvalds committed
401 402 403 404 405 406 407 408
	int retval, i, size;

	/* 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
409
	if (!interpreter->f_op->mmap)
Linus Torvalds's avatar
Linus Torvalds committed
410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425
		goto out;

	/*
	 * If the size of this structure has changed, then punt, since
	 * we will be doing the wrong thing.
	 */
	if (interp_elf_ex->e_phentsize != sizeof(struct elf_phdr))
		goto out;
	if (interp_elf_ex->e_phnum < 1 ||
		interp_elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr))
		goto out;

	/* Now read in all of the header information */
	size = sizeof(struct elf_phdr) * interp_elf_ex->e_phnum;
	if (size > ELF_MIN_ALIGN)
		goto out;
426
	elf_phdata = kmalloc(size, GFP_KERNEL);
Linus Torvalds's avatar
Linus Torvalds committed
427 428 429
	if (!elf_phdata)
		goto out;

430
	retval = kernel_read(interpreter, interp_elf_ex->e_phoff,
Mikael Pettersson's avatar
Mikael Pettersson committed
431
			     (char *)elf_phdata, size);
Linus Torvalds's avatar
Linus Torvalds committed
432 433 434 435 436 437 438
	error = -EIO;
	if (retval != size) {
		if (retval < 0)
			error = retval;	
		goto out_close;
	}

439 440 441 442 443 444
	total_size = total_mapping_size(elf_phdata, interp_elf_ex->e_phnum);
	if (!total_size) {
		error = -EINVAL;
		goto out_close;
	}

Linus Torvalds's avatar
Linus Torvalds committed
445
	eppnt = elf_phdata;
446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461
	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;
462 463
			else if (no_base && interp_elf_ex->e_type == ET_DYN)
				load_addr = -vaddr;
464 465

			map_addr = elf_map(interpreter, load_addr + vaddr,
466
					eppnt, elf_prot, elf_type, total_size);
467 468 469
			total_size = 0;
			if (!*interp_map_addr)
				*interp_map_addr = map_addr;
470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485
			error = map_addr;
			if (BAD_ADDR(map_addr))
				goto out_close;

			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;
486
			if (BAD_ADDR(k) ||
487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509
			    eppnt->p_filesz > eppnt->p_memsz ||
			    eppnt->p_memsz > TASK_SIZE ||
			    TASK_SIZE - eppnt->p_memsz < k) {
				error = -ENOMEM;
				goto out_close;
			}

			/*
			 * 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
510 511
	}

512 513 514 515 516 517 518 519 520 521 522
	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;
			goto out_close;
		}
Linus Torvalds's avatar
Linus Torvalds committed
523

524 525
		/* What we have mapped so far */
		elf_bss = ELF_PAGESTART(elf_bss + ELF_MIN_ALIGN - 1);
Linus Torvalds's avatar
Linus Torvalds committed
526

527
		/* Map the last of the bss segment */
528
		error = vm_brk(elf_bss, last_bss - elf_bss);
Linus Torvalds's avatar
Linus Torvalds committed
529 530 531 532
		if (BAD_ADDR(error))
			goto out_close;
	}

533
	error = load_addr;
Linus Torvalds's avatar
Linus Torvalds committed
534 535 536 537 538 539 540 541 542 543 544 545 546 547 548

out_close:
	kfree(elf_phdata);
out:
	return error;
}

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

#define INTERPRETER_NONE 0
#define INTERPRETER_ELF 2

549
#ifndef STACK_RND_MASK
550
#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))	/* 8MB of VA */
551
#endif
Linus Torvalds's avatar
Linus Torvalds committed
552 553 554 555 556

static unsigned long randomize_stack_top(unsigned long stack_top)
{
	unsigned int random_variable = 0;

557 558
	if ((current->flags & PF_RANDOMIZE) &&
		!(current->personality & ADDR_NO_RANDOMIZE)) {
559 560 561
		random_variable = get_random_int() & STACK_RND_MASK;
		random_variable <<= PAGE_SHIFT;
	}
Linus Torvalds's avatar
Linus Torvalds committed
562
#ifdef CONFIG_STACK_GROWSUP
563
	return PAGE_ALIGN(stack_top) + random_variable;
Linus Torvalds's avatar
Linus Torvalds committed
564
#else
565
	return PAGE_ALIGN(stack_top) - random_variable;
Linus Torvalds's avatar
Linus Torvalds committed
566 567 568
#endif
}

569
static int load_elf_binary(struct linux_binprm *bprm)
Linus Torvalds's avatar
Linus Torvalds committed
570 571 572 573 574 575
{
	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;
576
	struct elf_phdr *elf_ppnt, *elf_phdata;
Linus Torvalds's avatar
Linus Torvalds committed
577 578 579
	unsigned long elf_bss, elf_brk;
	int retval, i;
	unsigned int size;
580 581
	unsigned long elf_entry;
	unsigned long interp_load_addr = 0;
Linus Torvalds's avatar
Linus Torvalds committed
582
	unsigned long start_code, end_code, start_data, end_data;
583
	unsigned long reloc_func_desc __maybe_unused = 0;
584
	int executable_stack = EXSTACK_DEFAULT;
Linus Torvalds's avatar
Linus Torvalds committed
585
	unsigned long def_flags = 0;
586
	struct pt_regs *regs = current_pt_regs();
Linus Torvalds's avatar
Linus Torvalds committed
587 588 589 590 591 592 593 594 595 596 597 598
	struct {
		struct elfhdr elf_ex;
		struct elfhdr interp_elf_ex;
	} *loc;

	loc = kmalloc(sizeof(*loc), GFP_KERNEL);
	if (!loc) {
		retval = -ENOMEM;
		goto out_ret;
	}
	
	/* Get the exec-header */
599
	loc->elf_ex = *((struct elfhdr *)bprm->buf);
Linus Torvalds's avatar
Linus Torvalds committed
600 601 602 603 604 605 606 607 608 609

	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
610
	if (!bprm->file->f_op->mmap)
Linus Torvalds's avatar
Linus Torvalds committed
611 612 613 614 615 616 617 618 619 620
		goto out;

	/* Now read in all of the header information */
	if (loc->elf_ex.e_phentsize != sizeof(struct elf_phdr))
		goto out;
	if (loc->elf_ex.e_phnum < 1 ||
	 	loc->elf_ex.e_phnum > 65536U / sizeof(struct elf_phdr))
		goto out;
	size = loc->elf_ex.e_phnum * sizeof(struct elf_phdr);
	retval = -ENOMEM;
621
	elf_phdata = kmalloc(size, GFP_KERNEL);
Linus Torvalds's avatar
Linus Torvalds committed
622 623 624
	if (!elf_phdata)
		goto out;

625 626
	retval = kernel_read(bprm->file, loc->elf_ex.e_phoff,
			     (char *)elf_phdata, size);
Linus Torvalds's avatar
Linus Torvalds committed
627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650
	if (retval != size) {
		if (retval >= 0)
			retval = -EIO;
		goto out_free_ph;
	}

	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)
651
				goto out_free_ph;
Linus Torvalds's avatar
Linus Torvalds committed
652 653

			retval = -ENOMEM;
654
			elf_interpreter = kmalloc(elf_ppnt->p_filesz,
655
						  GFP_KERNEL);
Linus Torvalds's avatar
Linus Torvalds committed
656
			if (!elf_interpreter)
657
				goto out_free_ph;
Linus Torvalds's avatar
Linus Torvalds committed
658 659

			retval = kernel_read(bprm->file, elf_ppnt->p_offset,
660 661
					     elf_interpreter,
					     elf_ppnt->p_filesz);
Linus Torvalds's avatar
Linus Torvalds committed
662 663 664 665 666 667 668 669 670 671 672 673 674 675
			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;
676 677 678 679 680 681

			/*
			 * If the binary is not readable then enforce
			 * mm->dumpable = 0 regardless of the interpreter's
			 * permissions.
			 */
682
			would_dump(bprm, interpreter);
683

684 685
			retval = kernel_read(interpreter, 0, bprm->buf,
					     BINPRM_BUF_SIZE);
Linus Torvalds's avatar
Linus Torvalds committed
686 687 688 689 690 691 692
			if (retval != BINPRM_BUF_SIZE) {
				if (retval >= 0)
					retval = -EIO;
				goto out_free_dentry;
			}

			/* Get the exec headers */
693
			loc->interp_elf_ex = *((struct elfhdr *)bprm->buf);
Linus Torvalds's avatar
Linus Torvalds committed
694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711
			break;
		}
		elf_ppnt++;
	}

	elf_ppnt = elf_phdata;
	for (i = 0; i < loc->elf_ex.e_phnum; i++, elf_ppnt++)
		if (elf_ppnt->p_type == PT_GNU_STACK) {
			if (elf_ppnt->p_flags & PF_X)
				executable_stack = EXSTACK_ENABLE_X;
			else
				executable_stack = EXSTACK_DISABLE_X;
			break;
		}

	/* Some simple consistency checks for the interpreter */
	if (elf_interpreter) {
		retval = -ELIBBAD;
712 713
		/* Not an ELF interpreter */
		if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
Linus Torvalds's avatar
Linus Torvalds committed
714 715
			goto out_free_dentry;
		/* Verify the interpreter has a valid arch */
716
		if (!elf_check_arch(&loc->interp_elf_ex))
Linus Torvalds's avatar
Linus Torvalds committed
717 718 719 720 721 722 723 724 725 726 727 728 729
			goto out_free_dentry;
	}

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

	/* OK, This is the point of no return */
	current->mm->def_flags = def_flags;

	/* Do this immediately, since STACK_TOP as used in setup_arg_pages
	   may depend on the personality.  */
730
	SET_PERSONALITY(loc->elf_ex);
Linus Torvalds's avatar
Linus Torvalds committed
731 732 733
	if (elf_read_implies_exec(loc->elf_ex, executable_stack))
		current->personality |= READ_IMPLIES_EXEC;

734
	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
Linus Torvalds's avatar
Linus Torvalds committed
735
		current->flags |= PF_RANDOMIZE;
736 737

	setup_new_exec(bprm);
Linus Torvalds's avatar
Linus Torvalds committed
738 739 740 741 742 743 744 745 746 747 748 749

	/* 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);
	if (retval < 0) {
		send_sig(SIGKILL, current, 0);
		goto out_free_dentry;
	}
	
	current->mm->start_stack = bprm->p;

750
	/* Now we do a little grungy work by mmapping the ELF image into
751
	   the correct location in memory. */
752 753
	for(i = 0, elf_ppnt = elf_phdata;
	    i < loc->elf_ex.e_phnum; i++, elf_ppnt++) {
Linus Torvalds's avatar
Linus Torvalds committed
754 755 756 757 758 759 760 761 762 763 764 765
		int elf_prot = 0, elf_flags;
		unsigned long k, vaddr;

		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
766 767
			retval = set_brk(elf_bss + load_bias,
					 elf_brk + load_bias);
Linus Torvalds's avatar
Linus Torvalds committed
768 769 770 771 772 773 774 775 776 777 778 779 780
			if (retval) {
				send_sig(SIGKILL, current, 0);
				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
781
					 * file specifies odd protections. So
Linus Torvalds's avatar
Linus Torvalds committed
782 783 784 785 786 787
					 * we don't check the return value
					 */
				}
			}
		}

788 789 790 791 792 793
		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
794

795
		elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE;
Linus Torvalds's avatar
Linus Torvalds committed
796 797 798 799 800

		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) {
801 802 803 804
			/* 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.  */
805
#ifdef CONFIG_ARCH_BINFMT_ELF_RANDOMIZE_PIE
806
			/* Memory randomization might have been switched off
807 808
			 * in runtime via sysctl or explicit setting of
			 * personality flags.
809 810 811 812 813 814 815 816
			 * 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);
817
#else
818
			load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
819
#endif
Linus Torvalds's avatar
Linus Torvalds committed
820 821
		}

822
		error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
823
				elf_prot, elf_flags, 0);
Linus Torvalds's avatar
Linus Torvalds committed
824 825
		if (BAD_ADDR(error)) {
			send_sig(SIGKILL, current, 0);
826 827
			retval = IS_ERR((void *)error) ?
				PTR_ERR((void*)error) : -EINVAL;
Linus Torvalds's avatar
Linus Torvalds committed
828 829 830 831 832 833 834 835 836 837 838 839 840 841
			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;
842 843 844 845
		if (k < start_code)
			start_code = k;
		if (start_data < k)
			start_data = k;
Linus Torvalds's avatar
Linus Torvalds committed
846 847 848 849 850 851

		/*
		 * 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.
		 */
852
		if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
Linus Torvalds's avatar
Linus Torvalds committed
853 854
		    elf_ppnt->p_memsz > TASK_SIZE ||
		    TASK_SIZE - elf_ppnt->p_memsz < k) {
855
			/* set_brk can never work. Avoid overflows. */
Linus Torvalds's avatar
Linus Torvalds committed
856
			send_sig(SIGKILL, current, 0);
857
			retval = -EINVAL;
Linus Torvalds's avatar
Linus Torvalds committed
858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891
			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);
	if (retval) {
		send_sig(SIGKILL, current, 0);
		goto out_free_dentry;
	}
892
	if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) {
Linus Torvalds's avatar
Linus Torvalds committed
893 894 895 896 897 898
		send_sig(SIGSEGV, current, 0);
		retval = -EFAULT; /* Nobody gets to see this, but.. */
		goto out_free_dentry;
	}

	if (elf_interpreter) {
899
		unsigned long interp_map_addr = 0;
900 901 902 903 904 905 906 907 908 909 910 911

		elf_entry = load_elf_interp(&loc->interp_elf_ex,
					    interpreter,
					    &interp_map_addr,
					    load_bias);
		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;
912
		}
Linus Torvalds's avatar
Linus Torvalds committed
913 914
		if (BAD_ADDR(elf_entry)) {
			force_sig(SIGSEGV, current);
915 916
			retval = IS_ERR((void *)elf_entry) ?
					(int)elf_entry : -EINVAL;
Linus Torvalds's avatar
Linus Torvalds committed
917 918 919 920 921 922 923 924 925
			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;
926
		if (BAD_ADDR(elf_entry)) {
927 928
			force_sig(SIGSEGV, current);
			retval = -EINVAL;
929 930
			goto out_free_dentry;
		}
Linus Torvalds's avatar
Linus Torvalds committed
931 932 933 934 935 936
	}

	kfree(elf_phdata);

	set_binfmt(&elf_format);

937
#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
938
	retval = arch_setup_additional_pages(bprm, !!elf_interpreter);
939 940
	if (retval < 0) {
		send_sig(SIGKILL, current, 0);
941
		goto out;
942 943 944
	}
#endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */

945
	install_exec_creds(bprm);
946
	retval = create_elf_tables(bprm, &loc->elf_ex,
947
			  load_addr, interp_load_addr);
948 949 950 951
	if (retval < 0) {
		send_sig(SIGKILL, current, 0);
		goto out;
	}
Linus Torvalds's avatar
Linus Torvalds committed
952 953 954 955 956 957 958
	/* 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
959
#ifdef arch_randomize_brk
960
	if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1)) {
Jiri Kosina's avatar
Jiri Kosina committed
961 962
		current->mm->brk = current->mm->start_brk =
			arch_randomize_brk(current->mm);
963 964 965 966
#ifdef CONFIG_COMPAT_BRK
		current->brk_randomized = 1;
#endif
	}
Jiri Kosina's avatar
Jiri Kosina committed
967 968
#endif

Linus Torvalds's avatar
Linus Torvalds committed
969 970 971 972
	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
973
		   emulate the SVr4 behavior. Sigh. */
974
		error = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
Linus Torvalds's avatar
Linus Torvalds committed
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 1000 1001 1002 1003 1004
				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:
	allow_write_access(interpreter);
	if (interpreter)
		fput(interpreter);
out_free_interp:
Jesper Juhl's avatar
Jesper Juhl committed
1005
	kfree(elf_interpreter);
Linus Torvalds's avatar
Linus Torvalds committed
1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021
out_free_ph:
	kfree(elf_phdata);
	goto out;
}

/* 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;
1022
	retval = kernel_read(file, 0, (char *)&elf_ex, sizeof(elf_ex));
Linus Torvalds's avatar
Linus Torvalds committed
1023 1024 1025 1026 1027 1028 1029 1030
	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
1031
	    !elf_check_arch(&elf_ex) || !file->f_op->mmap)
Linus Torvalds's avatar
Linus Torvalds committed
1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059
		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. */
1060
	error = vm_mmap(file,
Linus Torvalds's avatar
Linus Torvalds committed
1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076
			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;
	}

1077 1078
	len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr +
			    ELF_MIN_ALIGN - 1);
Linus Torvalds's avatar
Linus Torvalds committed
1079
	bss = eppnt->p_memsz + eppnt->p_vaddr;
1080 1081
	if (bss > len)
		vm_brk(len, bss - len);
Linus Torvalds's avatar
Linus Torvalds committed
1082 1083 1084 1085 1086 1087 1088 1089
	error = 0;

out_free_ph:
	kfree(elf_phdata);
out:
	return error;
}

1090
#ifdef CONFIG_ELF_CORE
Linus Torvalds's avatar
Linus Torvalds committed
1091 1092 1093 1094 1095 1096 1097
/*
 * ELF core dumper
 *
 * Modelled on fs/exec.c:aout_core_dump()
 * Jeremy Fitzhardinge <jeremy@sw.oz.au>
 */

1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120
/*
 * 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;
	/*
	 * 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
1121
/*
Roland McGrath's avatar
Roland McGrath committed
1122
 * Decide what to dump of a segment, part, all or none.
Linus Torvalds's avatar
Linus Torvalds committed
1123
 */
Roland McGrath's avatar
Roland McGrath committed
1124 1125
static unsigned long vma_dump_size(struct vm_area_struct *vma,
				   unsigned long mm_flags)
Linus Torvalds's avatar
Linus Torvalds committed
1126
{
1127 1128
#define FILTER(type)	(mm_flags & (1UL << MMF_DUMP_##type))

1129 1130
	/* always dump the vdso and vsyscall sections */
	if (always_dump_vma(vma))
Roland McGrath's avatar
Roland McGrath committed
1131
		goto whole;
Roland McGrath's avatar
Roland McGrath committed
1132

1133
	if (vma->vm_flags & VM_DONTDUMP)
1134 1135
		return 0;

1136 1137 1138 1139 1140 1141
	/* 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;
1142
		return 0;
1143 1144
	}

Linus Torvalds's avatar
Linus Torvalds committed
1145
	/* Do not dump I/O mapped devices or special mappings */
1146
	if (vma->vm_flags & VM_IO)
Linus Torvalds's avatar
Linus Torvalds committed
1147 1148
		return 0;

1149 1150
	/* By default, dump shared memory if mapped from an anonymous file. */
	if (vma->vm_flags & VM_SHARED) {
Al Viro's avatar
Al Viro committed
1151
		if (file_inode(vma->vm_file)->i_nlink == 0 ?
Roland McGrath's avatar
Roland McGrath committed
1152 1153 1154
		    FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
			goto whole;
		return 0;
1155
	}
Linus Torvalds's avatar
Linus Torvalds committed
1156

Roland McGrath's avatar
Roland McGrath committed
1157 1158 1159 1160 1161
	/* 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
1162

Roland McGrath's avatar
Roland McGrath committed
1163 1164 1165 1166 1167 1168 1169 1170
	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.
	 */
1171 1172
	if (FILTER(ELF_HEADERS) &&
	    vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
Roland McGrath's avatar
Roland McGrath committed
1173 1174
		u32 __user *header = (u32 __user *) vma->vm_start;
		u32 word;
1175
		mm_segment_t fs = get_fs();
Roland McGrath's avatar
Roland McGrath committed
1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187
		/*
		 * 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;
1188 1189 1190 1191 1192 1193 1194 1195 1196
		/*
		 * 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
1197 1198 1199 1200 1201 1202 1203 1204 1205
			return PAGE_SIZE;
	}

#undef	FILTER

	return 0;

whole:
	return vma->vm_end - vma->vm_start;
Linus Torvalds's avatar
Linus Torvalds committed
1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227
}

/* 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
1228
static int alignfile(struct coredump_params *cprm)
Linus Torvalds's avatar
Linus Torvalds committed
1229
{
1230
	static const char buf[4] = { 0, };
Al Viro's avatar
Al Viro committed
1231
	return dump_emit(cprm, buf, roundup(cprm->written, 4) - cprm->written);
1232
}
Linus Torvalds's avatar
Linus Torvalds committed
1233

Al Viro's avatar
Al Viro committed
1234
static int writenote(struct memelfnote *men, struct coredump_params *cprm)
1235 1236
{
	struct elf_note en;
Linus Torvalds's avatar
Linus Torvalds committed
1237 1238 1239 1240
	en.n_namesz = strlen(men->name) + 1;
	en.n_descsz = men->datasz;
	en.n_type = men->type;

Al Viro's avatar
Al Viro committed
1241 1242 1243
	return dump_emit(cprm, &en, sizeof(en)) &&
	    dump_emit(cprm, men->name, en.n_namesz) && alignfile(cprm) &&
	    dump_emit(cprm, men->data, men->datasz) && alignfile(cprm);
Linus Torvalds's avatar
Linus Torvalds committed
1244 1245
}

Roland McGrath's avatar
Roland McGrath committed
1246
static void fill_elf_header(struct elfhdr *elf, int segs,
1247
			    u16 machine, u32 flags)
Linus Torvalds's avatar
Linus Torvalds committed
1248
{
1249 1250
	memset(elf, 0, sizeof(*elf));

Linus Torvalds's avatar
Linus Torvalds committed
1251 1252 1253 1254 1255 1256 1257
	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
1258
	elf->e_machine = machine;
Linus Torvalds's avatar
Linus Torvalds committed
1259 1260
	elf->e_version = EV_CURRENT;
	elf->e_phoff = sizeof(struct elfhdr);
Roland McGrath's avatar
Roland McGrath committed
1261
	elf->e_flags = flags;
Linus Torvalds's avatar
Linus Torvalds committed
1262 1263 1264
	elf->e_ehsize = sizeof(struct elfhdr);
	elf->e_phentsize = sizeof(struct elf_phdr);
	elf->e_phnum = segs;
1265

Linus Torvalds's avatar
Linus Torvalds committed
1266 1267 1268
	return;
}

1269
static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
Linus Torvalds's avatar
Linus Torvalds committed
1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292
{
	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;
}

/*
1293 1294
 * 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
1295 1296
 */
static void fill_prstatus(struct elf_prstatus *prstatus,
1297
		struct task_struct *p, long signr)
Linus Torvalds's avatar
Linus Torvalds committed
1298 1299 1300 1301
{
	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
	prstatus->pr_sigpend = p->pending.signal.sig[0];
	prstatus->pr_sighold = p->blocked.sig[0];
1302 1303 1304
	rcu_read_lock();
	prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
	rcu_read_unlock();
1305 1306 1307
	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
1308
	if (thread_group_leader(p)) {
1309 1310
		struct task_cputime cputime;

Linus Torvalds's avatar
Linus Torvalds committed
1311
		/*
1312 1313
		 * 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
1314
		 */
1315 1316 1317
		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
1318
	} else {
1319 1320 1321 1322 1323
		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
1324 1325 1326 1327 1328 1329 1330 1331
	}
	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)
{
1332
	const struct cred *cred;
1333
	unsigned int i, len;
Linus Torvalds's avatar
Linus Torvalds committed
1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348
	
	/* first copy the parameters from user space */
	memset(psinfo, 0, sizeof(struct elf_prpsinfo));

	len = mm->arg_end - mm->arg_start;
	if (len >= ELF_PRARGSZ)
		len = ELF_PRARGSZ-1;
	if (copy_from_user(&psinfo->pr_psargs,
		           (const char __user *)mm->arg_start, len))
		return -EFAULT;
	for(i = 0; i < len; i++)
		if (psinfo->pr_psargs[i] == 0)
			psinfo->pr_psargs[i] = ' ';
	psinfo->pr_psargs[len] = 0;

1349 1350 1351
	rcu_read_lock();
	psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
	rcu_read_unlock();
1352 1353 1354
	psinfo->pr_pid = task_pid_vnr(p);
	psinfo->pr_pgrp = task_pgrp_vnr(p);
	psinfo->pr_sid = task_session_vnr(p);
Linus Torvalds's avatar
Linus Torvalds committed
1355 1356 1357

	i = p->state ? ffz(~p->state) + 1 : 0;
	psinfo->pr_state = i;
1358
	psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
Linus Torvalds's avatar
Linus Torvalds committed
1359 1360 1361
	psinfo->pr_zomb = psinfo->pr_sname == 'Z';
	psinfo->pr_nice = task_nice(p);
	psinfo->pr_flag = p->flags;
1362 1363
	rcu_read_lock();
	cred = __task_cred(p);
1364 1365
	SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
	SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
1366
	rcu_read_unlock();
Linus Torvalds's avatar
Linus Torvalds committed
1367 1368 1369 1370 1371
	strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
	
	return 0;
}

Roland McGrath's avatar
Roland McGrath committed
1372 1373 1374 1375 1376 1377 1378 1379 1380 1381
static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
{
	elf_addr_t *auxv = (elf_addr_t *) mm->saved_auxv;
	int i = 0;
	do
		i += 2;
	while (auxv[i - 2] != AT_NULL);
	fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
}

1382 1383 1384 1385 1386 1387 1388 1389 1390 1391
static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,
		siginfo_t *siginfo)
{
	mm_segment_t old_fs = get_fs();
	set_fs(KERNEL_DS);
	copy_siginfo_to_user((user_siginfo_t __user *) csigdata, siginfo);
	set_fs(old_fs);
	fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata);
}

1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403
#define MAX_FILE_NOTE_SIZE (4*1024*1024)
/*
 * Format of NT_FILE note:
 *
 * long count     -- how many files are mapped
 * long page_size -- units for file_ofs
 * array of [COUNT] elements of
 *   long start
 *   long end
 *   long file_ofs
 * followed by COUNT filenames in ASCII: "FILE1" NUL "FILE2" NUL...
 */
1404
static int fill_files_note(struct memelfnote *note)
1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418
{
	struct vm_area_struct *vma;
	unsigned count, size, names_ofs, remaining, n;
	user_long_t *data;
	user_long_t *start_end_ofs;
	char *name_base, *name_curpos;

	/* *Estimated* file count and total data size needed */
	count = current->mm->map_count;
	size = count * 64;

	names_ofs = (2 + 3 * count) * sizeof(data[0]);
 alloc:
	if (size >= MAX_FILE_NOTE_SIZE) /* paranoia check */
1419
		return -EINVAL;
1420 1421 1422
	size = round_up(size, PAGE_SIZE);
	data = vmalloc(size);
	if (!data)
1423
		return -ENOMEM;
1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475

	start_end_ofs = data + 2;
	name_base = name_curpos = ((char *)data) + names_ofs;
	remaining = size - names_ofs;
	count = 0;
	for (vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) {
		struct file *file;
		const char *filename;

		file = vma->vm_file;
		if (!file)
			continue;
		filename = d_path(&file->f_path, name_curpos, remaining);
		if (IS_ERR(filename)) {
			if (PTR_ERR(filename) == -ENAMETOOLONG) {
				vfree(data);
				size = size * 5 / 4;
				goto alloc;
			}
			continue;
		}

		/* d_path() fills at the end, move name down */
		/* n = strlen(filename) + 1: */
		n = (name_curpos + remaining) - filename;
		remaining = filename - name_curpos;
		memmove(name_curpos, filename, n);
		name_curpos += n;

		*start_end_ofs++ = vma->vm_start;
		*start_end_ofs++ = vma->vm_end;
		*start_end_ofs++ = vma->vm_pgoff;
		count++;
	}

	/* Now we know exact count of files, can store it */
	data[0] = count;
	data[1] = PAGE_SIZE;
	/*
	 * Count usually is less than current->mm->map_count,
	 * we need to move filenames down.
	 */
	n = current->mm->map_count - count;
	if (n != 0) {
		unsigned shift_bytes = n * 3 * sizeof(data[0]);
		memmove(name_base - shift_bytes, name_base,
			name_curpos - name_base);
		name_curpos -= shift_bytes;
	}

	size = name_curpos - (char *)data;
	fill_note(note, "CORE", NT_FILE, size, data);
1476
	return 0;
1477 1478
}

1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 1489 1490 1491
#ifdef CORE_DUMP_USE_REGSET
#include <linux/regset.h>

struct elf_thread_core_info {
	struct elf_thread_core_info *next;
	struct task_struct *task;
	struct elf_prstatus prstatus;
	struct memelfnote notes[0];
};

struct elf_note_info {
	struct elf_thread_core_info *thread;
	struct memelfnote psinfo;
1492
	struct memelfnote signote;
1493
	struct memelfnote auxv;
1494
	struct memelfnote files;
1495
	user_siginfo_t csigdata;
1496 1497 1498 1499
	size_t size;
	int thread_notes;
};

1500 1501 1502 1503 1504 1505 1506 1507 1508 1509 1510 1511
/*
 * When a regset has a writeback hook, we call it on each thread before
 * dumping user memory.  On register window machines, this makes sure the
 * user memory backing the register data is up to date before we read it.
 */
static void do_thread_regset_writeback(struct task_struct *task,
				       const struct user_regset *regset)
{
	if (regset->writeback)
		regset->writeback(task, regset, 1);
}

1512 1513 1514 1515 1516 1517 1518 1519 1520 1521 1522 1523 1524 1525 1526 1527
#ifndef PR_REG_SIZE
#define PR_REG_SIZE(S) sizeof(S)
#endif

#ifndef PRSTATUS_SIZE
#define PRSTATUS_SIZE(S) sizeof(S)
#endif

#ifndef PR_REG_PTR
#define PR_REG_PTR(S) (&((S)->pr_reg))
#endif

#ifndef SET_PR_FPVALID
#define SET_PR_FPVALID(S, V) ((S)->pr_fpvalid = (V))
#endif

1528 1529 1530 1531 1532 1533 1534 1535 1536 1537 1538 1539 1540 1541
static int fill_thread_core_info(struct elf_thread_core_info *t,
				 const struct user_regset_view *view,
				 long signr, size_t *total)
{
	unsigned int i;

	/*
	 * NT_PRSTATUS is the one special case, because the regset data
	 * goes into the pr_reg field inside the note contents, rather
	 * than being the whole note contents.  We fill the reset in here.
	 * We assume that regset 0 is NT_PRSTATUS.
	 */
	fill_prstatus(&t->prstatus, t->task, signr);
	(void) view->regsets[0].get(t->task, &view->regsets[0],
1542 1543
				    0, PR_REG_SIZE(t->prstatus.pr_reg),
				    PR_REG_PTR(&t->prstatus), NULL);
1544 1545

	fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
1546
		  PRSTATUS_SIZE(t->prstatus), &t->prstatus);
1547 1548
	*total += notesize(&t->notes[0]);

1549 1550
	do_thread_regset_writeback(t->task, &view->regsets[0]);

1551 1552 1553 1554 1555 1556 1557
	/*
	 * Each other regset might generate a note too.  For each regset
	 * that has no core_note_type or is inactive, we leave t->notes[i]
	 * all zero and we'll know to skip writing it later.
	 */
	for (i = 1; i < view->n; ++i) {
		const struct user_regset *regset = &view->regsets[i];
1558
		do_thread_regset_writeback(t->task, regset);
1559
		if (regset->core_note_type && regset->get &&
1560 1561 1562 1563 1564 1565 1566 1567 1568 1569 1570 1571 1572 1573 1574 1575
		    (!regset->active || regset->active(t->task, regset))) {
			int ret;
			size_t size = regset->n * regset->size;
			void *data = kmalloc(size, GFP_KERNEL);
			if (unlikely(!data))
				return 0;
			ret = regset->get(t->task, regset,
					  0, size, data, NULL);
			if (unlikely(ret))
				kfree(data);
			else {
				if (regset->core_note_type != NT_PRFPREG)
					fill_note(&t->notes[i], "LINUX",
						  regset->core_note_type,
						  size, data);
				else {
H. J. Lu's avatar