xref: /openbmc/linux/fs/binfmt_elf.c (revision e8e0929d)
1 /*
2  * linux/fs/binfmt_elf.c
3  *
4  * These are the functions used to load ELF format executables as used
5  * on SVr4 machines.  Information on the format may be found in the book
6  * "UNIX SYSTEM V RELEASE 4 Programmers Guide: Ansi C and Programming Support
7  * Tools".
8  *
9  * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
10  */
11 
12 #include <linux/module.h>
13 #include <linux/kernel.h>
14 #include <linux/fs.h>
15 #include <linux/mm.h>
16 #include <linux/mman.h>
17 #include <linux/errno.h>
18 #include <linux/signal.h>
19 #include <linux/binfmts.h>
20 #include <linux/string.h>
21 #include <linux/file.h>
22 #include <linux/slab.h>
23 #include <linux/personality.h>
24 #include <linux/elfcore.h>
25 #include <linux/init.h>
26 #include <linux/highuid.h>
27 #include <linux/compiler.h>
28 #include <linux/highmem.h>
29 #include <linux/pagemap.h>
30 #include <linux/security.h>
31 #include <linux/random.h>
32 #include <linux/elf.h>
33 #include <linux/utsname.h>
34 #include <asm/uaccess.h>
35 #include <asm/param.h>
36 #include <asm/page.h>
37 
38 static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs);
39 static int load_elf_library(struct file *);
40 static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *,
41 				int, int, unsigned long);
42 
43 /*
44  * If we don't support core dumping, then supply a NULL so we
45  * don't even try.
46  */
47 #if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
48 static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit);
49 #else
50 #define elf_core_dump	NULL
51 #endif
52 
53 #if ELF_EXEC_PAGESIZE > PAGE_SIZE
54 #define ELF_MIN_ALIGN	ELF_EXEC_PAGESIZE
55 #else
56 #define ELF_MIN_ALIGN	PAGE_SIZE
57 #endif
58 
59 #ifndef ELF_CORE_EFLAGS
60 #define ELF_CORE_EFLAGS	0
61 #endif
62 
63 #define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
64 #define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
65 #define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
66 
67 static struct linux_binfmt elf_format = {
68 		.module		= THIS_MODULE,
69 		.load_binary	= load_elf_binary,
70 		.load_shlib	= load_elf_library,
71 		.core_dump	= elf_core_dump,
72 		.min_coredump	= ELF_EXEC_PAGESIZE,
73 		.hasvdso	= 1
74 };
75 
76 #define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
77 
78 static int set_brk(unsigned long start, unsigned long end)
79 {
80 	start = ELF_PAGEALIGN(start);
81 	end = ELF_PAGEALIGN(end);
82 	if (end > start) {
83 		unsigned long addr;
84 		down_write(&current->mm->mmap_sem);
85 		addr = do_brk(start, end - start);
86 		up_write(&current->mm->mmap_sem);
87 		if (BAD_ADDR(addr))
88 			return addr;
89 	}
90 	current->mm->start_brk = current->mm->brk = end;
91 	return 0;
92 }
93 
94 /* We need to explicitly zero any fractional pages
95    after the data section (i.e. bss).  This would
96    contain the junk from the file that should not
97    be in memory
98  */
99 static int padzero(unsigned long elf_bss)
100 {
101 	unsigned long nbyte;
102 
103 	nbyte = ELF_PAGEOFFSET(elf_bss);
104 	if (nbyte) {
105 		nbyte = ELF_MIN_ALIGN - nbyte;
106 		if (clear_user((void __user *) elf_bss, nbyte))
107 			return -EFAULT;
108 	}
109 	return 0;
110 }
111 
112 /* Let's use some macros to make this stack manipulation a little clearer */
113 #ifdef CONFIG_STACK_GROWSUP
114 #define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) + (items))
115 #define STACK_ROUND(sp, items) \
116 	((15 + (unsigned long) ((sp) + (items))) &~ 15UL)
117 #define STACK_ALLOC(sp, len) ({ \
118 	elf_addr_t __user *old_sp = (elf_addr_t __user *)sp; sp += len; \
119 	old_sp; })
120 #else
121 #define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) - (items))
122 #define STACK_ROUND(sp, items) \
123 	(((unsigned long) (sp - items)) &~ 15UL)
124 #define STACK_ALLOC(sp, len) ({ sp -= len ; sp; })
125 #endif
126 
127 #ifndef ELF_BASE_PLATFORM
128 /*
129  * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
130  * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
131  * will be copied to the user stack in the same manner as AT_PLATFORM.
132  */
133 #define ELF_BASE_PLATFORM NULL
134 #endif
135 
136 static int
137 create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
138 		unsigned long load_addr, unsigned long interp_load_addr)
139 {
140 	unsigned long p = bprm->p;
141 	int argc = bprm->argc;
142 	int envc = bprm->envc;
143 	elf_addr_t __user *argv;
144 	elf_addr_t __user *envp;
145 	elf_addr_t __user *sp;
146 	elf_addr_t __user *u_platform;
147 	elf_addr_t __user *u_base_platform;
148 	elf_addr_t __user *u_rand_bytes;
149 	const char *k_platform = ELF_PLATFORM;
150 	const char *k_base_platform = ELF_BASE_PLATFORM;
151 	unsigned char k_rand_bytes[16];
152 	int items;
153 	elf_addr_t *elf_info;
154 	int ei_index = 0;
155 	const struct cred *cred = current_cred();
156 	struct vm_area_struct *vma;
157 
158 	/*
159 	 * In some cases (e.g. Hyper-Threading), we want to avoid L1
160 	 * evictions by the processes running on the same package. One
161 	 * thing we can do is to shuffle the initial stack for them.
162 	 */
163 
164 	p = arch_align_stack(p);
165 
166 	/*
167 	 * If this architecture has a platform capability string, copy it
168 	 * to userspace.  In some cases (Sparc), this info is impossible
169 	 * for userspace to get any other way, in others (i386) it is
170 	 * merely difficult.
171 	 */
172 	u_platform = NULL;
173 	if (k_platform) {
174 		size_t len = strlen(k_platform) + 1;
175 
176 		u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
177 		if (__copy_to_user(u_platform, k_platform, len))
178 			return -EFAULT;
179 	}
180 
181 	/*
182 	 * If this architecture has a "base" platform capability
183 	 * string, copy it to userspace.
184 	 */
185 	u_base_platform = NULL;
186 	if (k_base_platform) {
187 		size_t len = strlen(k_base_platform) + 1;
188 
189 		u_base_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
190 		if (__copy_to_user(u_base_platform, k_base_platform, len))
191 			return -EFAULT;
192 	}
193 
194 	/*
195 	 * Generate 16 random bytes for userspace PRNG seeding.
196 	 */
197 	get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));
198 	u_rand_bytes = (elf_addr_t __user *)
199 		       STACK_ALLOC(p, sizeof(k_rand_bytes));
200 	if (__copy_to_user(u_rand_bytes, k_rand_bytes, sizeof(k_rand_bytes)))
201 		return -EFAULT;
202 
203 	/* Create the ELF interpreter info */
204 	elf_info = (elf_addr_t *)current->mm->saved_auxv;
205 	/* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */
206 #define NEW_AUX_ENT(id, val) \
207 	do { \
208 		elf_info[ei_index++] = id; \
209 		elf_info[ei_index++] = val; \
210 	} while (0)
211 
212 #ifdef ARCH_DLINFO
213 	/*
214 	 * ARCH_DLINFO must come first so PPC can do its special alignment of
215 	 * AUXV.
216 	 * update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT() in
217 	 * ARCH_DLINFO changes
218 	 */
219 	ARCH_DLINFO;
220 #endif
221 	NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
222 	NEW_AUX_ENT(AT_PAGESZ, ELF_EXEC_PAGESIZE);
223 	NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
224 	NEW_AUX_ENT(AT_PHDR, load_addr + exec->e_phoff);
225 	NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
226 	NEW_AUX_ENT(AT_PHNUM, exec->e_phnum);
227 	NEW_AUX_ENT(AT_BASE, interp_load_addr);
228 	NEW_AUX_ENT(AT_FLAGS, 0);
229 	NEW_AUX_ENT(AT_ENTRY, exec->e_entry);
230 	NEW_AUX_ENT(AT_UID, cred->uid);
231 	NEW_AUX_ENT(AT_EUID, cred->euid);
232 	NEW_AUX_ENT(AT_GID, cred->gid);
233 	NEW_AUX_ENT(AT_EGID, cred->egid);
234  	NEW_AUX_ENT(AT_SECURE, security_bprm_secureexec(bprm));
235 	NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
236 	NEW_AUX_ENT(AT_EXECFN, bprm->exec);
237 	if (k_platform) {
238 		NEW_AUX_ENT(AT_PLATFORM,
239 			    (elf_addr_t)(unsigned long)u_platform);
240 	}
241 	if (k_base_platform) {
242 		NEW_AUX_ENT(AT_BASE_PLATFORM,
243 			    (elf_addr_t)(unsigned long)u_base_platform);
244 	}
245 	if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
246 		NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
247 	}
248 #undef NEW_AUX_ENT
249 	/* AT_NULL is zero; clear the rest too */
250 	memset(&elf_info[ei_index], 0,
251 	       sizeof current->mm->saved_auxv - ei_index * sizeof elf_info[0]);
252 
253 	/* And advance past the AT_NULL entry.  */
254 	ei_index += 2;
255 
256 	sp = STACK_ADD(p, ei_index);
257 
258 	items = (argc + 1) + (envc + 1) + 1;
259 	bprm->p = STACK_ROUND(sp, items);
260 
261 	/* Point sp at the lowest address on the stack */
262 #ifdef CONFIG_STACK_GROWSUP
263 	sp = (elf_addr_t __user *)bprm->p - items - ei_index;
264 	bprm->exec = (unsigned long)sp; /* XXX: PARISC HACK */
265 #else
266 	sp = (elf_addr_t __user *)bprm->p;
267 #endif
268 
269 
270 	/*
271 	 * Grow the stack manually; some architectures have a limit on how
272 	 * far ahead a user-space access may be in order to grow the stack.
273 	 */
274 	vma = find_extend_vma(current->mm, bprm->p);
275 	if (!vma)
276 		return -EFAULT;
277 
278 	/* Now, let's put argc (and argv, envp if appropriate) on the stack */
279 	if (__put_user(argc, sp++))
280 		return -EFAULT;
281 	argv = sp;
282 	envp = argv + argc + 1;
283 
284 	/* Populate argv and envp */
285 	p = current->mm->arg_end = current->mm->arg_start;
286 	while (argc-- > 0) {
287 		size_t len;
288 		if (__put_user((elf_addr_t)p, argv++))
289 			return -EFAULT;
290 		len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
291 		if (!len || len > MAX_ARG_STRLEN)
292 			return -EINVAL;
293 		p += len;
294 	}
295 	if (__put_user(0, argv))
296 		return -EFAULT;
297 	current->mm->arg_end = current->mm->env_start = p;
298 	while (envc-- > 0) {
299 		size_t len;
300 		if (__put_user((elf_addr_t)p, envp++))
301 			return -EFAULT;
302 		len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
303 		if (!len || len > MAX_ARG_STRLEN)
304 			return -EINVAL;
305 		p += len;
306 	}
307 	if (__put_user(0, envp))
308 		return -EFAULT;
309 	current->mm->env_end = p;
310 
311 	/* Put the elf_info on the stack in the right place.  */
312 	sp = (elf_addr_t __user *)envp + 1;
313 	if (copy_to_user(sp, elf_info, ei_index * sizeof(elf_addr_t)))
314 		return -EFAULT;
315 	return 0;
316 }
317 
318 #ifndef elf_map
319 
320 static unsigned long elf_map(struct file *filep, unsigned long addr,
321 		struct elf_phdr *eppnt, int prot, int type,
322 		unsigned long total_size)
323 {
324 	unsigned long map_addr;
325 	unsigned long size = eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr);
326 	unsigned long off = eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr);
327 	addr = ELF_PAGESTART(addr);
328 	size = ELF_PAGEALIGN(size);
329 
330 	/* mmap() will return -EINVAL if given a zero size, but a
331 	 * segment with zero filesize is perfectly valid */
332 	if (!size)
333 		return addr;
334 
335 	down_write(&current->mm->mmap_sem);
336 	/*
337 	* total_size is the size of the ELF (interpreter) image.
338 	* The _first_ mmap needs to know the full size, otherwise
339 	* randomization might put this image into an overlapping
340 	* position with the ELF binary image. (since size < total_size)
341 	* So we first map the 'big' image - and unmap the remainder at
342 	* the end. (which unmap is needed for ELF images with holes.)
343 	*/
344 	if (total_size) {
345 		total_size = ELF_PAGEALIGN(total_size);
346 		map_addr = do_mmap(filep, addr, total_size, prot, type, off);
347 		if (!BAD_ADDR(map_addr))
348 			do_munmap(current->mm, map_addr+size, total_size-size);
349 	} else
350 		map_addr = do_mmap(filep, addr, size, prot, type, off);
351 
352 	up_write(&current->mm->mmap_sem);
353 	return(map_addr);
354 }
355 
356 #endif /* !elf_map */
357 
358 static unsigned long total_mapping_size(struct elf_phdr *cmds, int nr)
359 {
360 	int i, first_idx = -1, last_idx = -1;
361 
362 	for (i = 0; i < nr; i++) {
363 		if (cmds[i].p_type == PT_LOAD) {
364 			last_idx = i;
365 			if (first_idx == -1)
366 				first_idx = i;
367 		}
368 	}
369 	if (first_idx == -1)
370 		return 0;
371 
372 	return cmds[last_idx].p_vaddr + cmds[last_idx].p_memsz -
373 				ELF_PAGESTART(cmds[first_idx].p_vaddr);
374 }
375 
376 
377 /* This is much more generalized than the library routine read function,
378    so we keep this separate.  Technically the library read function
379    is only provided so that we can read a.out libraries that have
380    an ELF header */
381 
382 static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
383 		struct file *interpreter, unsigned long *interp_map_addr,
384 		unsigned long no_base)
385 {
386 	struct elf_phdr *elf_phdata;
387 	struct elf_phdr *eppnt;
388 	unsigned long load_addr = 0;
389 	int load_addr_set = 0;
390 	unsigned long last_bss = 0, elf_bss = 0;
391 	unsigned long error = ~0UL;
392 	unsigned long total_size;
393 	int retval, i, size;
394 
395 	/* First of all, some simple consistency checks */
396 	if (interp_elf_ex->e_type != ET_EXEC &&
397 	    interp_elf_ex->e_type != ET_DYN)
398 		goto out;
399 	if (!elf_check_arch(interp_elf_ex))
400 		goto out;
401 	if (!interpreter->f_op || !interpreter->f_op->mmap)
402 		goto out;
403 
404 	/*
405 	 * If the size of this structure has changed, then punt, since
406 	 * we will be doing the wrong thing.
407 	 */
408 	if (interp_elf_ex->e_phentsize != sizeof(struct elf_phdr))
409 		goto out;
410 	if (interp_elf_ex->e_phnum < 1 ||
411 		interp_elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr))
412 		goto out;
413 
414 	/* Now read in all of the header information */
415 	size = sizeof(struct elf_phdr) * interp_elf_ex->e_phnum;
416 	if (size > ELF_MIN_ALIGN)
417 		goto out;
418 	elf_phdata = kmalloc(size, GFP_KERNEL);
419 	if (!elf_phdata)
420 		goto out;
421 
422 	retval = kernel_read(interpreter, interp_elf_ex->e_phoff,
423 			     (char *)elf_phdata,size);
424 	error = -EIO;
425 	if (retval != size) {
426 		if (retval < 0)
427 			error = retval;
428 		goto out_close;
429 	}
430 
431 	total_size = total_mapping_size(elf_phdata, interp_elf_ex->e_phnum);
432 	if (!total_size) {
433 		error = -EINVAL;
434 		goto out_close;
435 	}
436 
437 	eppnt = elf_phdata;
438 	for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
439 		if (eppnt->p_type == PT_LOAD) {
440 			int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
441 			int elf_prot = 0;
442 			unsigned long vaddr = 0;
443 			unsigned long k, map_addr;
444 
445 			if (eppnt->p_flags & PF_R)
446 		    		elf_prot = PROT_READ;
447 			if (eppnt->p_flags & PF_W)
448 				elf_prot |= PROT_WRITE;
449 			if (eppnt->p_flags & PF_X)
450 				elf_prot |= PROT_EXEC;
451 			vaddr = eppnt->p_vaddr;
452 			if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
453 				elf_type |= MAP_FIXED;
454 			else if (no_base && interp_elf_ex->e_type == ET_DYN)
455 				load_addr = -vaddr;
456 
457 			map_addr = elf_map(interpreter, load_addr + vaddr,
458 					eppnt, elf_prot, elf_type, total_size);
459 			total_size = 0;
460 			if (!*interp_map_addr)
461 				*interp_map_addr = map_addr;
462 			error = map_addr;
463 			if (BAD_ADDR(map_addr))
464 				goto out_close;
465 
466 			if (!load_addr_set &&
467 			    interp_elf_ex->e_type == ET_DYN) {
468 				load_addr = map_addr - ELF_PAGESTART(vaddr);
469 				load_addr_set = 1;
470 			}
471 
472 			/*
473 			 * Check to see if the section's size will overflow the
474 			 * allowed task size. Note that p_filesz must always be
475 			 * <= p_memsize so it's only necessary to check p_memsz.
476 			 */
477 			k = load_addr + eppnt->p_vaddr;
478 			if (BAD_ADDR(k) ||
479 			    eppnt->p_filesz > eppnt->p_memsz ||
480 			    eppnt->p_memsz > TASK_SIZE ||
481 			    TASK_SIZE - eppnt->p_memsz < k) {
482 				error = -ENOMEM;
483 				goto out_close;
484 			}
485 
486 			/*
487 			 * Find the end of the file mapping for this phdr, and
488 			 * keep track of the largest address we see for this.
489 			 */
490 			k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
491 			if (k > elf_bss)
492 				elf_bss = k;
493 
494 			/*
495 			 * Do the same thing for the memory mapping - between
496 			 * elf_bss and last_bss is the bss section.
497 			 */
498 			k = load_addr + eppnt->p_memsz + eppnt->p_vaddr;
499 			if (k > last_bss)
500 				last_bss = k;
501 		}
502 	}
503 
504 	if (last_bss > elf_bss) {
505 		/*
506 		 * Now fill out the bss section.  First pad the last page up
507 		 * to the page boundary, and then perform a mmap to make sure
508 		 * that there are zero-mapped pages up to and including the
509 		 * last bss page.
510 		 */
511 		if (padzero(elf_bss)) {
512 			error = -EFAULT;
513 			goto out_close;
514 		}
515 
516 		/* What we have mapped so far */
517 		elf_bss = ELF_PAGESTART(elf_bss + ELF_MIN_ALIGN - 1);
518 
519 		/* Map the last of the bss segment */
520 		down_write(&current->mm->mmap_sem);
521 		error = do_brk(elf_bss, last_bss - elf_bss);
522 		up_write(&current->mm->mmap_sem);
523 		if (BAD_ADDR(error))
524 			goto out_close;
525 	}
526 
527 	error = load_addr;
528 
529 out_close:
530 	kfree(elf_phdata);
531 out:
532 	return error;
533 }
534 
535 /*
536  * These are the functions used to load ELF style executables and shared
537  * libraries.  There is no binary dependent code anywhere else.
538  */
539 
540 #define INTERPRETER_NONE 0
541 #define INTERPRETER_ELF 2
542 
543 #ifndef STACK_RND_MASK
544 #define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))	/* 8MB of VA */
545 #endif
546 
547 static unsigned long randomize_stack_top(unsigned long stack_top)
548 {
549 	unsigned int random_variable = 0;
550 
551 	if ((current->flags & PF_RANDOMIZE) &&
552 		!(current->personality & ADDR_NO_RANDOMIZE)) {
553 		random_variable = get_random_int() & STACK_RND_MASK;
554 		random_variable <<= PAGE_SHIFT;
555 	}
556 #ifdef CONFIG_STACK_GROWSUP
557 	return PAGE_ALIGN(stack_top) + random_variable;
558 #else
559 	return PAGE_ALIGN(stack_top) - random_variable;
560 #endif
561 }
562 
563 static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
564 {
565 	struct file *interpreter = NULL; /* to shut gcc up */
566  	unsigned long load_addr = 0, load_bias = 0;
567 	int load_addr_set = 0;
568 	char * elf_interpreter = NULL;
569 	unsigned long error;
570 	struct elf_phdr *elf_ppnt, *elf_phdata;
571 	unsigned long elf_bss, elf_brk;
572 	int retval, i;
573 	unsigned int size;
574 	unsigned long elf_entry;
575 	unsigned long interp_load_addr = 0;
576 	unsigned long start_code, end_code, start_data, end_data;
577 	unsigned long reloc_func_desc = 0;
578 	int executable_stack = EXSTACK_DEFAULT;
579 	unsigned long def_flags = 0;
580 	struct {
581 		struct elfhdr elf_ex;
582 		struct elfhdr interp_elf_ex;
583 	} *loc;
584 
585 	loc = kmalloc(sizeof(*loc), GFP_KERNEL);
586 	if (!loc) {
587 		retval = -ENOMEM;
588 		goto out_ret;
589 	}
590 
591 	/* Get the exec-header */
592 	loc->elf_ex = *((struct elfhdr *)bprm->buf);
593 
594 	retval = -ENOEXEC;
595 	/* First of all, some simple consistency checks */
596 	if (memcmp(loc->elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
597 		goto out;
598 
599 	if (loc->elf_ex.e_type != ET_EXEC && loc->elf_ex.e_type != ET_DYN)
600 		goto out;
601 	if (!elf_check_arch(&loc->elf_ex))
602 		goto out;
603 	if (!bprm->file->f_op||!bprm->file->f_op->mmap)
604 		goto out;
605 
606 	/* Now read in all of the header information */
607 	if (loc->elf_ex.e_phentsize != sizeof(struct elf_phdr))
608 		goto out;
609 	if (loc->elf_ex.e_phnum < 1 ||
610 	 	loc->elf_ex.e_phnum > 65536U / sizeof(struct elf_phdr))
611 		goto out;
612 	size = loc->elf_ex.e_phnum * sizeof(struct elf_phdr);
613 	retval = -ENOMEM;
614 	elf_phdata = kmalloc(size, GFP_KERNEL);
615 	if (!elf_phdata)
616 		goto out;
617 
618 	retval = kernel_read(bprm->file, loc->elf_ex.e_phoff,
619 			     (char *)elf_phdata, size);
620 	if (retval != size) {
621 		if (retval >= 0)
622 			retval = -EIO;
623 		goto out_free_ph;
624 	}
625 
626 	elf_ppnt = elf_phdata;
627 	elf_bss = 0;
628 	elf_brk = 0;
629 
630 	start_code = ~0UL;
631 	end_code = 0;
632 	start_data = 0;
633 	end_data = 0;
634 
635 	for (i = 0; i < loc->elf_ex.e_phnum; i++) {
636 		if (elf_ppnt->p_type == PT_INTERP) {
637 			/* This is the program interpreter used for
638 			 * shared libraries - for now assume that this
639 			 * is an a.out format binary
640 			 */
641 			retval = -ENOEXEC;
642 			if (elf_ppnt->p_filesz > PATH_MAX ||
643 			    elf_ppnt->p_filesz < 2)
644 				goto out_free_ph;
645 
646 			retval = -ENOMEM;
647 			elf_interpreter = kmalloc(elf_ppnt->p_filesz,
648 						  GFP_KERNEL);
649 			if (!elf_interpreter)
650 				goto out_free_ph;
651 
652 			retval = kernel_read(bprm->file, elf_ppnt->p_offset,
653 					     elf_interpreter,
654 					     elf_ppnt->p_filesz);
655 			if (retval != elf_ppnt->p_filesz) {
656 				if (retval >= 0)
657 					retval = -EIO;
658 				goto out_free_interp;
659 			}
660 			/* make sure path is NULL terminated */
661 			retval = -ENOEXEC;
662 			if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
663 				goto out_free_interp;
664 
665 			/*
666 			 * The early SET_PERSONALITY here is so that the lookup
667 			 * for the interpreter happens in the namespace of the
668 			 * to-be-execed image.  SET_PERSONALITY can select an
669 			 * alternate root.
670 			 *
671 			 * However, SET_PERSONALITY is NOT allowed to switch
672 			 * this task into the new images's memory mapping
673 			 * policy - that is, TASK_SIZE must still evaluate to
674 			 * that which is appropriate to the execing application.
675 			 * This is because exit_mmap() needs to have TASK_SIZE
676 			 * evaluate to the size of the old image.
677 			 *
678 			 * So if (say) a 64-bit application is execing a 32-bit
679 			 * application it is the architecture's responsibility
680 			 * to defer changing the value of TASK_SIZE until the
681 			 * switch really is going to happen - do this in
682 			 * flush_thread().	- akpm
683 			 */
684 			SET_PERSONALITY(loc->elf_ex);
685 
686 			interpreter = open_exec(elf_interpreter);
687 			retval = PTR_ERR(interpreter);
688 			if (IS_ERR(interpreter))
689 				goto out_free_interp;
690 
691 			/*
692 			 * If the binary is not readable then enforce
693 			 * mm->dumpable = 0 regardless of the interpreter's
694 			 * permissions.
695 			 */
696 			if (file_permission(interpreter, MAY_READ) < 0)
697 				bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
698 
699 			retval = kernel_read(interpreter, 0, bprm->buf,
700 					     BINPRM_BUF_SIZE);
701 			if (retval != BINPRM_BUF_SIZE) {
702 				if (retval >= 0)
703 					retval = -EIO;
704 				goto out_free_dentry;
705 			}
706 
707 			/* Get the exec headers */
708 			loc->interp_elf_ex = *((struct elfhdr *)bprm->buf);
709 			break;
710 		}
711 		elf_ppnt++;
712 	}
713 
714 	elf_ppnt = elf_phdata;
715 	for (i = 0; i < loc->elf_ex.e_phnum; i++, elf_ppnt++)
716 		if (elf_ppnt->p_type == PT_GNU_STACK) {
717 			if (elf_ppnt->p_flags & PF_X)
718 				executable_stack = EXSTACK_ENABLE_X;
719 			else
720 				executable_stack = EXSTACK_DISABLE_X;
721 			break;
722 		}
723 
724 	/* Some simple consistency checks for the interpreter */
725 	if (elf_interpreter) {
726 		retval = -ELIBBAD;
727 		/* Not an ELF interpreter */
728 		if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
729 			goto out_free_dentry;
730 		/* Verify the interpreter has a valid arch */
731 		if (!elf_check_arch(&loc->interp_elf_ex))
732 			goto out_free_dentry;
733 	} else {
734 		/* Executables without an interpreter also need a personality  */
735 		SET_PERSONALITY(loc->elf_ex);
736 	}
737 
738 	/* Flush all traces of the currently running executable */
739 	retval = flush_old_exec(bprm);
740 	if (retval)
741 		goto out_free_dentry;
742 
743 	/* OK, This is the point of no return */
744 	current->flags &= ~PF_FORKNOEXEC;
745 	current->mm->def_flags = def_flags;
746 
747 	/* Do this immediately, since STACK_TOP as used in setup_arg_pages
748 	   may depend on the personality.  */
749 	SET_PERSONALITY(loc->elf_ex);
750 	if (elf_read_implies_exec(loc->elf_ex, executable_stack))
751 		current->personality |= READ_IMPLIES_EXEC;
752 
753 	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
754 		current->flags |= PF_RANDOMIZE;
755 	arch_pick_mmap_layout(current->mm);
756 
757 	/* Do this so that we can load the interpreter, if need be.  We will
758 	   change some of these later */
759 	current->mm->free_area_cache = current->mm->mmap_base;
760 	current->mm->cached_hole_size = 0;
761 	retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
762 				 executable_stack);
763 	if (retval < 0) {
764 		send_sig(SIGKILL, current, 0);
765 		goto out_free_dentry;
766 	}
767 
768 	current->mm->start_stack = bprm->p;
769 
770 	/* Now we do a little grungy work by mmaping the ELF image into
771 	   the correct location in memory. */
772 	for(i = 0, elf_ppnt = elf_phdata;
773 	    i < loc->elf_ex.e_phnum; i++, elf_ppnt++) {
774 		int elf_prot = 0, elf_flags;
775 		unsigned long k, vaddr;
776 
777 		if (elf_ppnt->p_type != PT_LOAD)
778 			continue;
779 
780 		if (unlikely (elf_brk > elf_bss)) {
781 			unsigned long nbyte;
782 
783 			/* There was a PT_LOAD segment with p_memsz > p_filesz
784 			   before this one. Map anonymous pages, if needed,
785 			   and clear the area.  */
786 			retval = set_brk (elf_bss + load_bias,
787 					  elf_brk + load_bias);
788 			if (retval) {
789 				send_sig(SIGKILL, current, 0);
790 				goto out_free_dentry;
791 			}
792 			nbyte = ELF_PAGEOFFSET(elf_bss);
793 			if (nbyte) {
794 				nbyte = ELF_MIN_ALIGN - nbyte;
795 				if (nbyte > elf_brk - elf_bss)
796 					nbyte = elf_brk - elf_bss;
797 				if (clear_user((void __user *)elf_bss +
798 							load_bias, nbyte)) {
799 					/*
800 					 * This bss-zeroing can fail if the ELF
801 					 * file specifies odd protections. So
802 					 * we don't check the return value
803 					 */
804 				}
805 			}
806 		}
807 
808 		if (elf_ppnt->p_flags & PF_R)
809 			elf_prot |= PROT_READ;
810 		if (elf_ppnt->p_flags & PF_W)
811 			elf_prot |= PROT_WRITE;
812 		if (elf_ppnt->p_flags & PF_X)
813 			elf_prot |= PROT_EXEC;
814 
815 		elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE;
816 
817 		vaddr = elf_ppnt->p_vaddr;
818 		if (loc->elf_ex.e_type == ET_EXEC || load_addr_set) {
819 			elf_flags |= MAP_FIXED;
820 		} else if (loc->elf_ex.e_type == ET_DYN) {
821 			/* Try and get dynamic programs out of the way of the
822 			 * default mmap base, as well as whatever program they
823 			 * might try to exec.  This is because the brk will
824 			 * follow the loader, and is not movable.  */
825 #ifdef CONFIG_X86
826 			load_bias = 0;
827 #else
828 			load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
829 #endif
830 		}
831 
832 		error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
833 				elf_prot, elf_flags, 0);
834 		if (BAD_ADDR(error)) {
835 			send_sig(SIGKILL, current, 0);
836 			retval = IS_ERR((void *)error) ?
837 				PTR_ERR((void*)error) : -EINVAL;
838 			goto out_free_dentry;
839 		}
840 
841 		if (!load_addr_set) {
842 			load_addr_set = 1;
843 			load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset);
844 			if (loc->elf_ex.e_type == ET_DYN) {
845 				load_bias += error -
846 				             ELF_PAGESTART(load_bias + vaddr);
847 				load_addr += load_bias;
848 				reloc_func_desc = load_bias;
849 			}
850 		}
851 		k = elf_ppnt->p_vaddr;
852 		if (k < start_code)
853 			start_code = k;
854 		if (start_data < k)
855 			start_data = k;
856 
857 		/*
858 		 * Check to see if the section's size will overflow the
859 		 * allowed task size. Note that p_filesz must always be
860 		 * <= p_memsz so it is only necessary to check p_memsz.
861 		 */
862 		if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
863 		    elf_ppnt->p_memsz > TASK_SIZE ||
864 		    TASK_SIZE - elf_ppnt->p_memsz < k) {
865 			/* set_brk can never work. Avoid overflows. */
866 			send_sig(SIGKILL, current, 0);
867 			retval = -EINVAL;
868 			goto out_free_dentry;
869 		}
870 
871 		k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
872 
873 		if (k > elf_bss)
874 			elf_bss = k;
875 		if ((elf_ppnt->p_flags & PF_X) && end_code < k)
876 			end_code = k;
877 		if (end_data < k)
878 			end_data = k;
879 		k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
880 		if (k > elf_brk)
881 			elf_brk = k;
882 	}
883 
884 	loc->elf_ex.e_entry += load_bias;
885 	elf_bss += load_bias;
886 	elf_brk += load_bias;
887 	start_code += load_bias;
888 	end_code += load_bias;
889 	start_data += load_bias;
890 	end_data += load_bias;
891 
892 	/* Calling set_brk effectively mmaps the pages that we need
893 	 * for the bss and break sections.  We must do this before
894 	 * mapping in the interpreter, to make sure it doesn't wind
895 	 * up getting placed where the bss needs to go.
896 	 */
897 	retval = set_brk(elf_bss, elf_brk);
898 	if (retval) {
899 		send_sig(SIGKILL, current, 0);
900 		goto out_free_dentry;
901 	}
902 	if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) {
903 		send_sig(SIGSEGV, current, 0);
904 		retval = -EFAULT; /* Nobody gets to see this, but.. */
905 		goto out_free_dentry;
906 	}
907 
908 	if (elf_interpreter) {
909 		unsigned long uninitialized_var(interp_map_addr);
910 
911 		elf_entry = load_elf_interp(&loc->interp_elf_ex,
912 					    interpreter,
913 					    &interp_map_addr,
914 					    load_bias);
915 		if (!IS_ERR((void *)elf_entry)) {
916 			/*
917 			 * load_elf_interp() returns relocation
918 			 * adjustment
919 			 */
920 			interp_load_addr = elf_entry;
921 			elf_entry += loc->interp_elf_ex.e_entry;
922 		}
923 		if (BAD_ADDR(elf_entry)) {
924 			force_sig(SIGSEGV, current);
925 			retval = IS_ERR((void *)elf_entry) ?
926 					(int)elf_entry : -EINVAL;
927 			goto out_free_dentry;
928 		}
929 		reloc_func_desc = interp_load_addr;
930 
931 		allow_write_access(interpreter);
932 		fput(interpreter);
933 		kfree(elf_interpreter);
934 	} else {
935 		elf_entry = loc->elf_ex.e_entry;
936 		if (BAD_ADDR(elf_entry)) {
937 			force_sig(SIGSEGV, current);
938 			retval = -EINVAL;
939 			goto out_free_dentry;
940 		}
941 	}
942 
943 	kfree(elf_phdata);
944 
945 	set_binfmt(&elf_format);
946 
947 #ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
948 	retval = arch_setup_additional_pages(bprm, !!elf_interpreter);
949 	if (retval < 0) {
950 		send_sig(SIGKILL, current, 0);
951 		goto out;
952 	}
953 #endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
954 
955 	install_exec_creds(bprm);
956 	current->flags &= ~PF_FORKNOEXEC;
957 	retval = create_elf_tables(bprm, &loc->elf_ex,
958 			  load_addr, interp_load_addr);
959 	if (retval < 0) {
960 		send_sig(SIGKILL, current, 0);
961 		goto out;
962 	}
963 	/* N.B. passed_fileno might not be initialized? */
964 	current->mm->end_code = end_code;
965 	current->mm->start_code = start_code;
966 	current->mm->start_data = start_data;
967 	current->mm->end_data = end_data;
968 	current->mm->start_stack = bprm->p;
969 
970 #ifdef arch_randomize_brk
971 	if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1))
972 		current->mm->brk = current->mm->start_brk =
973 			arch_randomize_brk(current->mm);
974 #endif
975 
976 	if (current->personality & MMAP_PAGE_ZERO) {
977 		/* Why this, you ask???  Well SVr4 maps page 0 as read-only,
978 		   and some applications "depend" upon this behavior.
979 		   Since we do not have the power to recompile these, we
980 		   emulate the SVr4 behavior. Sigh. */
981 		down_write(&current->mm->mmap_sem);
982 		error = do_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
983 				MAP_FIXED | MAP_PRIVATE, 0);
984 		up_write(&current->mm->mmap_sem);
985 	}
986 
987 #ifdef ELF_PLAT_INIT
988 	/*
989 	 * The ABI may specify that certain registers be set up in special
990 	 * ways (on i386 %edx is the address of a DT_FINI function, for
991 	 * example.  In addition, it may also specify (eg, PowerPC64 ELF)
992 	 * that the e_entry field is the address of the function descriptor
993 	 * for the startup routine, rather than the address of the startup
994 	 * routine itself.  This macro performs whatever initialization to
995 	 * the regs structure is required as well as any relocations to the
996 	 * function descriptor entries when executing dynamically links apps.
997 	 */
998 	ELF_PLAT_INIT(regs, reloc_func_desc);
999 #endif
1000 
1001 	start_thread(regs, elf_entry, bprm->p);
1002 	retval = 0;
1003 out:
1004 	kfree(loc);
1005 out_ret:
1006 	return retval;
1007 
1008 	/* error cleanup */
1009 out_free_dentry:
1010 	allow_write_access(interpreter);
1011 	if (interpreter)
1012 		fput(interpreter);
1013 out_free_interp:
1014 	kfree(elf_interpreter);
1015 out_free_ph:
1016 	kfree(elf_phdata);
1017 	goto out;
1018 }
1019 
1020 /* This is really simpleminded and specialized - we are loading an
1021    a.out library that is given an ELF header. */
1022 static int load_elf_library(struct file *file)
1023 {
1024 	struct elf_phdr *elf_phdata;
1025 	struct elf_phdr *eppnt;
1026 	unsigned long elf_bss, bss, len;
1027 	int retval, error, i, j;
1028 	struct elfhdr elf_ex;
1029 
1030 	error = -ENOEXEC;
1031 	retval = kernel_read(file, 0, (char *)&elf_ex, sizeof(elf_ex));
1032 	if (retval != sizeof(elf_ex))
1033 		goto out;
1034 
1035 	if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
1036 		goto out;
1037 
1038 	/* First of all, some simple consistency checks */
1039 	if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
1040 	    !elf_check_arch(&elf_ex) || !file->f_op || !file->f_op->mmap)
1041 		goto out;
1042 
1043 	/* Now read in all of the header information */
1044 
1045 	j = sizeof(struct elf_phdr) * elf_ex.e_phnum;
1046 	/* j < ELF_MIN_ALIGN because elf_ex.e_phnum <= 2 */
1047 
1048 	error = -ENOMEM;
1049 	elf_phdata = kmalloc(j, GFP_KERNEL);
1050 	if (!elf_phdata)
1051 		goto out;
1052 
1053 	eppnt = elf_phdata;
1054 	error = -ENOEXEC;
1055 	retval = kernel_read(file, elf_ex.e_phoff, (char *)eppnt, j);
1056 	if (retval != j)
1057 		goto out_free_ph;
1058 
1059 	for (j = 0, i = 0; i<elf_ex.e_phnum; i++)
1060 		if ((eppnt + i)->p_type == PT_LOAD)
1061 			j++;
1062 	if (j != 1)
1063 		goto out_free_ph;
1064 
1065 	while (eppnt->p_type != PT_LOAD)
1066 		eppnt++;
1067 
1068 	/* Now use mmap to map the library into memory. */
1069 	down_write(&current->mm->mmap_sem);
1070 	error = do_mmap(file,
1071 			ELF_PAGESTART(eppnt->p_vaddr),
1072 			(eppnt->p_filesz +
1073 			 ELF_PAGEOFFSET(eppnt->p_vaddr)),
1074 			PROT_READ | PROT_WRITE | PROT_EXEC,
1075 			MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
1076 			(eppnt->p_offset -
1077 			 ELF_PAGEOFFSET(eppnt->p_vaddr)));
1078 	up_write(&current->mm->mmap_sem);
1079 	if (error != ELF_PAGESTART(eppnt->p_vaddr))
1080 		goto out_free_ph;
1081 
1082 	elf_bss = eppnt->p_vaddr + eppnt->p_filesz;
1083 	if (padzero(elf_bss)) {
1084 		error = -EFAULT;
1085 		goto out_free_ph;
1086 	}
1087 
1088 	len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr +
1089 			    ELF_MIN_ALIGN - 1);
1090 	bss = eppnt->p_memsz + eppnt->p_vaddr;
1091 	if (bss > len) {
1092 		down_write(&current->mm->mmap_sem);
1093 		do_brk(len, bss - len);
1094 		up_write(&current->mm->mmap_sem);
1095 	}
1096 	error = 0;
1097 
1098 out_free_ph:
1099 	kfree(elf_phdata);
1100 out:
1101 	return error;
1102 }
1103 
1104 /*
1105  * Note that some platforms still use traditional core dumps and not
1106  * the ELF core dump.  Each platform can select it as appropriate.
1107  */
1108 #if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
1109 
1110 /*
1111  * ELF core dumper
1112  *
1113  * Modelled on fs/exec.c:aout_core_dump()
1114  * Jeremy Fitzhardinge <jeremy@sw.oz.au>
1115  */
1116 /*
1117  * These are the only things you should do on a core-file: use only these
1118  * functions to write out all the necessary info.
1119  */
1120 static int dump_write(struct file *file, const void *addr, int nr)
1121 {
1122 	return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
1123 }
1124 
1125 static int dump_seek(struct file *file, loff_t off)
1126 {
1127 	if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
1128 		if (file->f_op->llseek(file, off, SEEK_CUR) < 0)
1129 			return 0;
1130 	} else {
1131 		char *buf = (char *)get_zeroed_page(GFP_KERNEL);
1132 		if (!buf)
1133 			return 0;
1134 		while (off > 0) {
1135 			unsigned long n = off;
1136 			if (n > PAGE_SIZE)
1137 				n = PAGE_SIZE;
1138 			if (!dump_write(file, buf, n))
1139 				return 0;
1140 			off -= n;
1141 		}
1142 		free_page((unsigned long)buf);
1143 	}
1144 	return 1;
1145 }
1146 
1147 /*
1148  * Decide what to dump of a segment, part, all or none.
1149  */
1150 static unsigned long vma_dump_size(struct vm_area_struct *vma,
1151 				   unsigned long mm_flags)
1152 {
1153 #define FILTER(type)	(mm_flags & (1UL << MMF_DUMP_##type))
1154 
1155 	/* The vma can be set up to tell us the answer directly.  */
1156 	if (vma->vm_flags & VM_ALWAYSDUMP)
1157 		goto whole;
1158 
1159 	/* Hugetlb memory check */
1160 	if (vma->vm_flags & VM_HUGETLB) {
1161 		if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
1162 			goto whole;
1163 		if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
1164 			goto whole;
1165 	}
1166 
1167 	/* Do not dump I/O mapped devices or special mappings */
1168 	if (vma->vm_flags & (VM_IO | VM_RESERVED))
1169 		return 0;
1170 
1171 	/* By default, dump shared memory if mapped from an anonymous file. */
1172 	if (vma->vm_flags & VM_SHARED) {
1173 		if (vma->vm_file->f_path.dentry->d_inode->i_nlink == 0 ?
1174 		    FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
1175 			goto whole;
1176 		return 0;
1177 	}
1178 
1179 	/* Dump segments that have been written to.  */
1180 	if (vma->anon_vma && FILTER(ANON_PRIVATE))
1181 		goto whole;
1182 	if (vma->vm_file == NULL)
1183 		return 0;
1184 
1185 	if (FILTER(MAPPED_PRIVATE))
1186 		goto whole;
1187 
1188 	/*
1189 	 * If this looks like the beginning of a DSO or executable mapping,
1190 	 * check for an ELF header.  If we find one, dump the first page to
1191 	 * aid in determining what was mapped here.
1192 	 */
1193 	if (FILTER(ELF_HEADERS) &&
1194 	    vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
1195 		u32 __user *header = (u32 __user *) vma->vm_start;
1196 		u32 word;
1197 		mm_segment_t fs = get_fs();
1198 		/*
1199 		 * Doing it this way gets the constant folded by GCC.
1200 		 */
1201 		union {
1202 			u32 cmp;
1203 			char elfmag[SELFMAG];
1204 		} magic;
1205 		BUILD_BUG_ON(SELFMAG != sizeof word);
1206 		magic.elfmag[EI_MAG0] = ELFMAG0;
1207 		magic.elfmag[EI_MAG1] = ELFMAG1;
1208 		magic.elfmag[EI_MAG2] = ELFMAG2;
1209 		magic.elfmag[EI_MAG3] = ELFMAG3;
1210 		/*
1211 		 * Switch to the user "segment" for get_user(),
1212 		 * then put back what elf_core_dump() had in place.
1213 		 */
1214 		set_fs(USER_DS);
1215 		if (unlikely(get_user(word, header)))
1216 			word = 0;
1217 		set_fs(fs);
1218 		if (word == magic.cmp)
1219 			return PAGE_SIZE;
1220 	}
1221 
1222 #undef	FILTER
1223 
1224 	return 0;
1225 
1226 whole:
1227 	return vma->vm_end - vma->vm_start;
1228 }
1229 
1230 /* An ELF note in memory */
1231 struct memelfnote
1232 {
1233 	const char *name;
1234 	int type;
1235 	unsigned int datasz;
1236 	void *data;
1237 };
1238 
1239 static int notesize(struct memelfnote *en)
1240 {
1241 	int sz;
1242 
1243 	sz = sizeof(struct elf_note);
1244 	sz += roundup(strlen(en->name) + 1, 4);
1245 	sz += roundup(en->datasz, 4);
1246 
1247 	return sz;
1248 }
1249 
1250 #define DUMP_WRITE(addr, nr, foffset)	\
1251 	do { if (!dump_write(file, (addr), (nr))) return 0; *foffset += (nr); } while(0)
1252 
1253 static int alignfile(struct file *file, loff_t *foffset)
1254 {
1255 	static const char buf[4] = { 0, };
1256 	DUMP_WRITE(buf, roundup(*foffset, 4) - *foffset, foffset);
1257 	return 1;
1258 }
1259 
1260 static int writenote(struct memelfnote *men, struct file *file,
1261 			loff_t *foffset)
1262 {
1263 	struct elf_note en;
1264 	en.n_namesz = strlen(men->name) + 1;
1265 	en.n_descsz = men->datasz;
1266 	en.n_type = men->type;
1267 
1268 	DUMP_WRITE(&en, sizeof(en), foffset);
1269 	DUMP_WRITE(men->name, en.n_namesz, foffset);
1270 	if (!alignfile(file, foffset))
1271 		return 0;
1272 	DUMP_WRITE(men->data, men->datasz, foffset);
1273 	if (!alignfile(file, foffset))
1274 		return 0;
1275 
1276 	return 1;
1277 }
1278 #undef DUMP_WRITE
1279 
1280 #define DUMP_WRITE(addr, nr)	\
1281 	if ((size += (nr)) > limit || !dump_write(file, (addr), (nr))) \
1282 		goto end_coredump;
1283 
1284 static void fill_elf_header(struct elfhdr *elf, int segs,
1285 			    u16 machine, u32 flags, u8 osabi)
1286 {
1287 	memset(elf, 0, sizeof(*elf));
1288 
1289 	memcpy(elf->e_ident, ELFMAG, SELFMAG);
1290 	elf->e_ident[EI_CLASS] = ELF_CLASS;
1291 	elf->e_ident[EI_DATA] = ELF_DATA;
1292 	elf->e_ident[EI_VERSION] = EV_CURRENT;
1293 	elf->e_ident[EI_OSABI] = ELF_OSABI;
1294 
1295 	elf->e_type = ET_CORE;
1296 	elf->e_machine = machine;
1297 	elf->e_version = EV_CURRENT;
1298 	elf->e_phoff = sizeof(struct elfhdr);
1299 	elf->e_flags = flags;
1300 	elf->e_ehsize = sizeof(struct elfhdr);
1301 	elf->e_phentsize = sizeof(struct elf_phdr);
1302 	elf->e_phnum = segs;
1303 
1304 	return;
1305 }
1306 
1307 static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
1308 {
1309 	phdr->p_type = PT_NOTE;
1310 	phdr->p_offset = offset;
1311 	phdr->p_vaddr = 0;
1312 	phdr->p_paddr = 0;
1313 	phdr->p_filesz = sz;
1314 	phdr->p_memsz = 0;
1315 	phdr->p_flags = 0;
1316 	phdr->p_align = 0;
1317 	return;
1318 }
1319 
1320 static void fill_note(struct memelfnote *note, const char *name, int type,
1321 		unsigned int sz, void *data)
1322 {
1323 	note->name = name;
1324 	note->type = type;
1325 	note->datasz = sz;
1326 	note->data = data;
1327 	return;
1328 }
1329 
1330 /*
1331  * fill up all the fields in prstatus from the given task struct, except
1332  * registers which need to be filled up separately.
1333  */
1334 static void fill_prstatus(struct elf_prstatus *prstatus,
1335 		struct task_struct *p, long signr)
1336 {
1337 	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1338 	prstatus->pr_sigpend = p->pending.signal.sig[0];
1339 	prstatus->pr_sighold = p->blocked.sig[0];
1340 	rcu_read_lock();
1341 	prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1342 	rcu_read_unlock();
1343 	prstatus->pr_pid = task_pid_vnr(p);
1344 	prstatus->pr_pgrp = task_pgrp_vnr(p);
1345 	prstatus->pr_sid = task_session_vnr(p);
1346 	if (thread_group_leader(p)) {
1347 		struct task_cputime cputime;
1348 
1349 		/*
1350 		 * This is the record for the group leader.  It shows the
1351 		 * group-wide total, not its individual thread total.
1352 		 */
1353 		thread_group_cputime(p, &cputime);
1354 		cputime_to_timeval(cputime.utime, &prstatus->pr_utime);
1355 		cputime_to_timeval(cputime.stime, &prstatus->pr_stime);
1356 	} else {
1357 		cputime_to_timeval(p->utime, &prstatus->pr_utime);
1358 		cputime_to_timeval(p->stime, &prstatus->pr_stime);
1359 	}
1360 	cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
1361 	cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);
1362 }
1363 
1364 static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
1365 		       struct mm_struct *mm)
1366 {
1367 	const struct cred *cred;
1368 	unsigned int i, len;
1369 
1370 	/* first copy the parameters from user space */
1371 	memset(psinfo, 0, sizeof(struct elf_prpsinfo));
1372 
1373 	len = mm->arg_end - mm->arg_start;
1374 	if (len >= ELF_PRARGSZ)
1375 		len = ELF_PRARGSZ-1;
1376 	if (copy_from_user(&psinfo->pr_psargs,
1377 		           (const char __user *)mm->arg_start, len))
1378 		return -EFAULT;
1379 	for(i = 0; i < len; i++)
1380 		if (psinfo->pr_psargs[i] == 0)
1381 			psinfo->pr_psargs[i] = ' ';
1382 	psinfo->pr_psargs[len] = 0;
1383 
1384 	rcu_read_lock();
1385 	psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1386 	rcu_read_unlock();
1387 	psinfo->pr_pid = task_pid_vnr(p);
1388 	psinfo->pr_pgrp = task_pgrp_vnr(p);
1389 	psinfo->pr_sid = task_session_vnr(p);
1390 
1391 	i = p->state ? ffz(~p->state) + 1 : 0;
1392 	psinfo->pr_state = i;
1393 	psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
1394 	psinfo->pr_zomb = psinfo->pr_sname == 'Z';
1395 	psinfo->pr_nice = task_nice(p);
1396 	psinfo->pr_flag = p->flags;
1397 	rcu_read_lock();
1398 	cred = __task_cred(p);
1399 	SET_UID(psinfo->pr_uid, cred->uid);
1400 	SET_GID(psinfo->pr_gid, cred->gid);
1401 	rcu_read_unlock();
1402 	strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
1403 
1404 	return 0;
1405 }
1406 
1407 static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
1408 {
1409 	elf_addr_t *auxv = (elf_addr_t *) mm->saved_auxv;
1410 	int i = 0;
1411 	do
1412 		i += 2;
1413 	while (auxv[i - 2] != AT_NULL);
1414 	fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
1415 }
1416 
1417 #ifdef CORE_DUMP_USE_REGSET
1418 #include <linux/regset.h>
1419 
1420 struct elf_thread_core_info {
1421 	struct elf_thread_core_info *next;
1422 	struct task_struct *task;
1423 	struct elf_prstatus prstatus;
1424 	struct memelfnote notes[0];
1425 };
1426 
1427 struct elf_note_info {
1428 	struct elf_thread_core_info *thread;
1429 	struct memelfnote psinfo;
1430 	struct memelfnote auxv;
1431 	size_t size;
1432 	int thread_notes;
1433 };
1434 
1435 /*
1436  * When a regset has a writeback hook, we call it on each thread before
1437  * dumping user memory.  On register window machines, this makes sure the
1438  * user memory backing the register data is up to date before we read it.
1439  */
1440 static void do_thread_regset_writeback(struct task_struct *task,
1441 				       const struct user_regset *regset)
1442 {
1443 	if (regset->writeback)
1444 		regset->writeback(task, regset, 1);
1445 }
1446 
1447 static int fill_thread_core_info(struct elf_thread_core_info *t,
1448 				 const struct user_regset_view *view,
1449 				 long signr, size_t *total)
1450 {
1451 	unsigned int i;
1452 
1453 	/*
1454 	 * NT_PRSTATUS is the one special case, because the regset data
1455 	 * goes into the pr_reg field inside the note contents, rather
1456 	 * than being the whole note contents.  We fill the reset in here.
1457 	 * We assume that regset 0 is NT_PRSTATUS.
1458 	 */
1459 	fill_prstatus(&t->prstatus, t->task, signr);
1460 	(void) view->regsets[0].get(t->task, &view->regsets[0],
1461 				    0, sizeof(t->prstatus.pr_reg),
1462 				    &t->prstatus.pr_reg, NULL);
1463 
1464 	fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
1465 		  sizeof(t->prstatus), &t->prstatus);
1466 	*total += notesize(&t->notes[0]);
1467 
1468 	do_thread_regset_writeback(t->task, &view->regsets[0]);
1469 
1470 	/*
1471 	 * Each other regset might generate a note too.  For each regset
1472 	 * that has no core_note_type or is inactive, we leave t->notes[i]
1473 	 * all zero and we'll know to skip writing it later.
1474 	 */
1475 	for (i = 1; i < view->n; ++i) {
1476 		const struct user_regset *regset = &view->regsets[i];
1477 		do_thread_regset_writeback(t->task, regset);
1478 		if (regset->core_note_type &&
1479 		    (!regset->active || regset->active(t->task, regset))) {
1480 			int ret;
1481 			size_t size = regset->n * regset->size;
1482 			void *data = kmalloc(size, GFP_KERNEL);
1483 			if (unlikely(!data))
1484 				return 0;
1485 			ret = regset->get(t->task, regset,
1486 					  0, size, data, NULL);
1487 			if (unlikely(ret))
1488 				kfree(data);
1489 			else {
1490 				if (regset->core_note_type != NT_PRFPREG)
1491 					fill_note(&t->notes[i], "LINUX",
1492 						  regset->core_note_type,
1493 						  size, data);
1494 				else {
1495 					t->prstatus.pr_fpvalid = 1;
1496 					fill_note(&t->notes[i], "CORE",
1497 						  NT_PRFPREG, size, data);
1498 				}
1499 				*total += notesize(&t->notes[i]);
1500 			}
1501 		}
1502 	}
1503 
1504 	return 1;
1505 }
1506 
1507 static int fill_note_info(struct elfhdr *elf, int phdrs,
1508 			  struct elf_note_info *info,
1509 			  long signr, struct pt_regs *regs)
1510 {
1511 	struct task_struct *dump_task = current;
1512 	const struct user_regset_view *view = task_user_regset_view(dump_task);
1513 	struct elf_thread_core_info *t;
1514 	struct elf_prpsinfo *psinfo;
1515 	struct core_thread *ct;
1516 	unsigned int i;
1517 
1518 	info->size = 0;
1519 	info->thread = NULL;
1520 
1521 	psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
1522 	if (psinfo == NULL)
1523 		return 0;
1524 
1525 	fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
1526 
1527 	/*
1528 	 * Figure out how many notes we're going to need for each thread.
1529 	 */
1530 	info->thread_notes = 0;
1531 	for (i = 0; i < view->n; ++i)
1532 		if (view->regsets[i].core_note_type != 0)
1533 			++info->thread_notes;
1534 
1535 	/*
1536 	 * Sanity check.  We rely on regset 0 being in NT_PRSTATUS,
1537 	 * since it is our one special case.
1538 	 */
1539 	if (unlikely(info->thread_notes == 0) ||
1540 	    unlikely(view->regsets[0].core_note_type != NT_PRSTATUS)) {
1541 		WARN_ON(1);
1542 		return 0;
1543 	}
1544 
1545 	/*
1546 	 * Initialize the ELF file header.
1547 	 */
1548 	fill_elf_header(elf, phdrs,
1549 			view->e_machine, view->e_flags, view->ei_osabi);
1550 
1551 	/*
1552 	 * Allocate a structure for each thread.
1553 	 */
1554 	for (ct = &dump_task->mm->core_state->dumper; ct; ct = ct->next) {
1555 		t = kzalloc(offsetof(struct elf_thread_core_info,
1556 				     notes[info->thread_notes]),
1557 			    GFP_KERNEL);
1558 		if (unlikely(!t))
1559 			return 0;
1560 
1561 		t->task = ct->task;
1562 		if (ct->task == dump_task || !info->thread) {
1563 			t->next = info->thread;
1564 			info->thread = t;
1565 		} else {
1566 			/*
1567 			 * Make sure to keep the original task at
1568 			 * the head of the list.
1569 			 */
1570 			t->next = info->thread->next;
1571 			info->thread->next = t;
1572 		}
1573 	}
1574 
1575 	/*
1576 	 * Now fill in each thread's information.
1577 	 */
1578 	for (t = info->thread; t != NULL; t = t->next)
1579 		if (!fill_thread_core_info(t, view, signr, &info->size))
1580 			return 0;
1581 
1582 	/*
1583 	 * Fill in the two process-wide notes.
1584 	 */
1585 	fill_psinfo(psinfo, dump_task->group_leader, dump_task->mm);
1586 	info->size += notesize(&info->psinfo);
1587 
1588 	fill_auxv_note(&info->auxv, current->mm);
1589 	info->size += notesize(&info->auxv);
1590 
1591 	return 1;
1592 }
1593 
1594 static size_t get_note_info_size(struct elf_note_info *info)
1595 {
1596 	return info->size;
1597 }
1598 
1599 /*
1600  * Write all the notes for each thread.  When writing the first thread, the
1601  * process-wide notes are interleaved after the first thread-specific note.
1602  */
1603 static int write_note_info(struct elf_note_info *info,
1604 			   struct file *file, loff_t *foffset)
1605 {
1606 	bool first = 1;
1607 	struct elf_thread_core_info *t = info->thread;
1608 
1609 	do {
1610 		int i;
1611 
1612 		if (!writenote(&t->notes[0], file, foffset))
1613 			return 0;
1614 
1615 		if (first && !writenote(&info->psinfo, file, foffset))
1616 			return 0;
1617 		if (first && !writenote(&info->auxv, file, foffset))
1618 			return 0;
1619 
1620 		for (i = 1; i < info->thread_notes; ++i)
1621 			if (t->notes[i].data &&
1622 			    !writenote(&t->notes[i], file, foffset))
1623 				return 0;
1624 
1625 		first = 0;
1626 		t = t->next;
1627 	} while (t);
1628 
1629 	return 1;
1630 }
1631 
1632 static void free_note_info(struct elf_note_info *info)
1633 {
1634 	struct elf_thread_core_info *threads = info->thread;
1635 	while (threads) {
1636 		unsigned int i;
1637 		struct elf_thread_core_info *t = threads;
1638 		threads = t->next;
1639 		WARN_ON(t->notes[0].data && t->notes[0].data != &t->prstatus);
1640 		for (i = 1; i < info->thread_notes; ++i)
1641 			kfree(t->notes[i].data);
1642 		kfree(t);
1643 	}
1644 	kfree(info->psinfo.data);
1645 }
1646 
1647 #else
1648 
1649 /* Here is the structure in which status of each thread is captured. */
1650 struct elf_thread_status
1651 {
1652 	struct list_head list;
1653 	struct elf_prstatus prstatus;	/* NT_PRSTATUS */
1654 	elf_fpregset_t fpu;		/* NT_PRFPREG */
1655 	struct task_struct *thread;
1656 #ifdef ELF_CORE_COPY_XFPREGS
1657 	elf_fpxregset_t xfpu;		/* ELF_CORE_XFPREG_TYPE */
1658 #endif
1659 	struct memelfnote notes[3];
1660 	int num_notes;
1661 };
1662 
1663 /*
1664  * In order to add the specific thread information for the elf file format,
1665  * we need to keep a linked list of every threads pr_status and then create
1666  * a single section for them in the final core file.
1667  */
1668 static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
1669 {
1670 	int sz = 0;
1671 	struct task_struct *p = t->thread;
1672 	t->num_notes = 0;
1673 
1674 	fill_prstatus(&t->prstatus, p, signr);
1675 	elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
1676 
1677 	fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
1678 		  &(t->prstatus));
1679 	t->num_notes++;
1680 	sz += notesize(&t->notes[0]);
1681 
1682 	if ((t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL,
1683 								&t->fpu))) {
1684 		fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
1685 			  &(t->fpu));
1686 		t->num_notes++;
1687 		sz += notesize(&t->notes[1]);
1688 	}
1689 
1690 #ifdef ELF_CORE_COPY_XFPREGS
1691 	if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
1692 		fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
1693 			  sizeof(t->xfpu), &t->xfpu);
1694 		t->num_notes++;
1695 		sz += notesize(&t->notes[2]);
1696 	}
1697 #endif
1698 	return sz;
1699 }
1700 
1701 struct elf_note_info {
1702 	struct memelfnote *notes;
1703 	struct elf_prstatus *prstatus;	/* NT_PRSTATUS */
1704 	struct elf_prpsinfo *psinfo;	/* NT_PRPSINFO */
1705 	struct list_head thread_list;
1706 	elf_fpregset_t *fpu;
1707 #ifdef ELF_CORE_COPY_XFPREGS
1708 	elf_fpxregset_t *xfpu;
1709 #endif
1710 	int thread_status_size;
1711 	int numnote;
1712 };
1713 
1714 static int elf_note_info_init(struct elf_note_info *info)
1715 {
1716 	memset(info, 0, sizeof(*info));
1717 	INIT_LIST_HEAD(&info->thread_list);
1718 
1719 	/* Allocate space for six ELF notes */
1720 	info->notes = kmalloc(6 * sizeof(struct memelfnote), GFP_KERNEL);
1721 	if (!info->notes)
1722 		return 0;
1723 	info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL);
1724 	if (!info->psinfo)
1725 		goto notes_free;
1726 	info->prstatus = kmalloc(sizeof(*info->prstatus), GFP_KERNEL);
1727 	if (!info->prstatus)
1728 		goto psinfo_free;
1729 	info->fpu = kmalloc(sizeof(*info->fpu), GFP_KERNEL);
1730 	if (!info->fpu)
1731 		goto prstatus_free;
1732 #ifdef ELF_CORE_COPY_XFPREGS
1733 	info->xfpu = kmalloc(sizeof(*info->xfpu), GFP_KERNEL);
1734 	if (!info->xfpu)
1735 		goto fpu_free;
1736 #endif
1737 	return 1;
1738 #ifdef ELF_CORE_COPY_XFPREGS
1739  fpu_free:
1740 	kfree(info->fpu);
1741 #endif
1742  prstatus_free:
1743 	kfree(info->prstatus);
1744  psinfo_free:
1745 	kfree(info->psinfo);
1746  notes_free:
1747 	kfree(info->notes);
1748 	return 0;
1749 }
1750 
1751 static int fill_note_info(struct elfhdr *elf, int phdrs,
1752 			  struct elf_note_info *info,
1753 			  long signr, struct pt_regs *regs)
1754 {
1755 	struct list_head *t;
1756 
1757 	if (!elf_note_info_init(info))
1758 		return 0;
1759 
1760 	if (signr) {
1761 		struct core_thread *ct;
1762 		struct elf_thread_status *ets;
1763 
1764 		for (ct = current->mm->core_state->dumper.next;
1765 						ct; ct = ct->next) {
1766 			ets = kzalloc(sizeof(*ets), GFP_KERNEL);
1767 			if (!ets)
1768 				return 0;
1769 
1770 			ets->thread = ct->task;
1771 			list_add(&ets->list, &info->thread_list);
1772 		}
1773 
1774 		list_for_each(t, &info->thread_list) {
1775 			int sz;
1776 
1777 			ets = list_entry(t, struct elf_thread_status, list);
1778 			sz = elf_dump_thread_status(signr, ets);
1779 			info->thread_status_size += sz;
1780 		}
1781 	}
1782 	/* now collect the dump for the current */
1783 	memset(info->prstatus, 0, sizeof(*info->prstatus));
1784 	fill_prstatus(info->prstatus, current, signr);
1785 	elf_core_copy_regs(&info->prstatus->pr_reg, regs);
1786 
1787 	/* Set up header */
1788 	fill_elf_header(elf, phdrs, ELF_ARCH, ELF_CORE_EFLAGS, ELF_OSABI);
1789 
1790 	/*
1791 	 * Set up the notes in similar form to SVR4 core dumps made
1792 	 * with info from their /proc.
1793 	 */
1794 
1795 	fill_note(info->notes + 0, "CORE", NT_PRSTATUS,
1796 		  sizeof(*info->prstatus), info->prstatus);
1797 	fill_psinfo(info->psinfo, current->group_leader, current->mm);
1798 	fill_note(info->notes + 1, "CORE", NT_PRPSINFO,
1799 		  sizeof(*info->psinfo), info->psinfo);
1800 
1801 	info->numnote = 2;
1802 
1803 	fill_auxv_note(&info->notes[info->numnote++], current->mm);
1804 
1805 	/* Try to dump the FPU. */
1806 	info->prstatus->pr_fpvalid = elf_core_copy_task_fpregs(current, regs,
1807 							       info->fpu);
1808 	if (info->prstatus->pr_fpvalid)
1809 		fill_note(info->notes + info->numnote++,
1810 			  "CORE", NT_PRFPREG, sizeof(*info->fpu), info->fpu);
1811 #ifdef ELF_CORE_COPY_XFPREGS
1812 	if (elf_core_copy_task_xfpregs(current, info->xfpu))
1813 		fill_note(info->notes + info->numnote++,
1814 			  "LINUX", ELF_CORE_XFPREG_TYPE,
1815 			  sizeof(*info->xfpu), info->xfpu);
1816 #endif
1817 
1818 	return 1;
1819 }
1820 
1821 static size_t get_note_info_size(struct elf_note_info *info)
1822 {
1823 	int sz = 0;
1824 	int i;
1825 
1826 	for (i = 0; i < info->numnote; i++)
1827 		sz += notesize(info->notes + i);
1828 
1829 	sz += info->thread_status_size;
1830 
1831 	return sz;
1832 }
1833 
1834 static int write_note_info(struct elf_note_info *info,
1835 			   struct file *file, loff_t *foffset)
1836 {
1837 	int i;
1838 	struct list_head *t;
1839 
1840 	for (i = 0; i < info->numnote; i++)
1841 		if (!writenote(info->notes + i, file, foffset))
1842 			return 0;
1843 
1844 	/* write out the thread status notes section */
1845 	list_for_each(t, &info->thread_list) {
1846 		struct elf_thread_status *tmp =
1847 				list_entry(t, struct elf_thread_status, list);
1848 
1849 		for (i = 0; i < tmp->num_notes; i++)
1850 			if (!writenote(&tmp->notes[i], file, foffset))
1851 				return 0;
1852 	}
1853 
1854 	return 1;
1855 }
1856 
1857 static void free_note_info(struct elf_note_info *info)
1858 {
1859 	while (!list_empty(&info->thread_list)) {
1860 		struct list_head *tmp = info->thread_list.next;
1861 		list_del(tmp);
1862 		kfree(list_entry(tmp, struct elf_thread_status, list));
1863 	}
1864 
1865 	kfree(info->prstatus);
1866 	kfree(info->psinfo);
1867 	kfree(info->notes);
1868 	kfree(info->fpu);
1869 #ifdef ELF_CORE_COPY_XFPREGS
1870 	kfree(info->xfpu);
1871 #endif
1872 }
1873 
1874 #endif
1875 
1876 static struct vm_area_struct *first_vma(struct task_struct *tsk,
1877 					struct vm_area_struct *gate_vma)
1878 {
1879 	struct vm_area_struct *ret = tsk->mm->mmap;
1880 
1881 	if (ret)
1882 		return ret;
1883 	return gate_vma;
1884 }
1885 /*
1886  * Helper function for iterating across a vma list.  It ensures that the caller
1887  * will visit `gate_vma' prior to terminating the search.
1888  */
1889 static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
1890 					struct vm_area_struct *gate_vma)
1891 {
1892 	struct vm_area_struct *ret;
1893 
1894 	ret = this_vma->vm_next;
1895 	if (ret)
1896 		return ret;
1897 	if (this_vma == gate_vma)
1898 		return NULL;
1899 	return gate_vma;
1900 }
1901 
1902 /*
1903  * Actual dumper
1904  *
1905  * This is a two-pass process; first we find the offsets of the bits,
1906  * and then they are actually written out.  If we run out of core limit
1907  * we just truncate.
1908  */
1909 static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit)
1910 {
1911 	int has_dumped = 0;
1912 	mm_segment_t fs;
1913 	int segs;
1914 	size_t size = 0;
1915 	struct vm_area_struct *vma, *gate_vma;
1916 	struct elfhdr *elf = NULL;
1917 	loff_t offset = 0, dataoff, foffset;
1918 	unsigned long mm_flags;
1919 	struct elf_note_info info;
1920 
1921 	/*
1922 	 * We no longer stop all VM operations.
1923 	 *
1924 	 * This is because those proceses that could possibly change map_count
1925 	 * or the mmap / vma pages are now blocked in do_exit on current
1926 	 * finishing this core dump.
1927 	 *
1928 	 * Only ptrace can touch these memory addresses, but it doesn't change
1929 	 * the map_count or the pages allocated. So no possibility of crashing
1930 	 * exists while dumping the mm->vm_next areas to the core file.
1931 	 */
1932 
1933 	/* alloc memory for large data structures: too large to be on stack */
1934 	elf = kmalloc(sizeof(*elf), GFP_KERNEL);
1935 	if (!elf)
1936 		goto out;
1937 	/*
1938 	 * The number of segs are recored into ELF header as 16bit value.
1939 	 * Please check DEFAULT_MAX_MAP_COUNT definition when you modify here.
1940 	 */
1941 	segs = current->mm->map_count;
1942 #ifdef ELF_CORE_EXTRA_PHDRS
1943 	segs += ELF_CORE_EXTRA_PHDRS;
1944 #endif
1945 
1946 	gate_vma = get_gate_vma(current);
1947 	if (gate_vma != NULL)
1948 		segs++;
1949 
1950 	/*
1951 	 * Collect all the non-memory information about the process for the
1952 	 * notes.  This also sets up the file header.
1953 	 */
1954 	if (!fill_note_info(elf, segs + 1, /* including notes section */
1955 			    &info, signr, regs))
1956 		goto cleanup;
1957 
1958 	has_dumped = 1;
1959 	current->flags |= PF_DUMPCORE;
1960 
1961 	fs = get_fs();
1962 	set_fs(KERNEL_DS);
1963 
1964 	DUMP_WRITE(elf, sizeof(*elf));
1965 	offset += sizeof(*elf);				/* Elf header */
1966 	offset += (segs + 1) * sizeof(struct elf_phdr); /* Program headers */
1967 	foffset = offset;
1968 
1969 	/* Write notes phdr entry */
1970 	{
1971 		struct elf_phdr phdr;
1972 		size_t sz = get_note_info_size(&info);
1973 
1974 		sz += elf_coredump_extra_notes_size();
1975 
1976 		fill_elf_note_phdr(&phdr, sz, offset);
1977 		offset += sz;
1978 		DUMP_WRITE(&phdr, sizeof(phdr));
1979 	}
1980 
1981 	dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
1982 
1983 	/*
1984 	 * We must use the same mm->flags while dumping core to avoid
1985 	 * inconsistency between the program headers and bodies, otherwise an
1986 	 * unusable core file can be generated.
1987 	 */
1988 	mm_flags = current->mm->flags;
1989 
1990 	/* Write program headers for segments dump */
1991 	for (vma = first_vma(current, gate_vma); vma != NULL;
1992 			vma = next_vma(vma, gate_vma)) {
1993 		struct elf_phdr phdr;
1994 
1995 		phdr.p_type = PT_LOAD;
1996 		phdr.p_offset = offset;
1997 		phdr.p_vaddr = vma->vm_start;
1998 		phdr.p_paddr = 0;
1999 		phdr.p_filesz = vma_dump_size(vma, mm_flags);
2000 		phdr.p_memsz = vma->vm_end - vma->vm_start;
2001 		offset += phdr.p_filesz;
2002 		phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
2003 		if (vma->vm_flags & VM_WRITE)
2004 			phdr.p_flags |= PF_W;
2005 		if (vma->vm_flags & VM_EXEC)
2006 			phdr.p_flags |= PF_X;
2007 		phdr.p_align = ELF_EXEC_PAGESIZE;
2008 
2009 		DUMP_WRITE(&phdr, sizeof(phdr));
2010 	}
2011 
2012 #ifdef ELF_CORE_WRITE_EXTRA_PHDRS
2013 	ELF_CORE_WRITE_EXTRA_PHDRS;
2014 #endif
2015 
2016  	/* write out the notes section */
2017 	if (!write_note_info(&info, file, &foffset))
2018 		goto end_coredump;
2019 
2020 	if (elf_coredump_extra_notes_write(file, &foffset))
2021 		goto end_coredump;
2022 
2023 	/* Align to page */
2024 	if (!dump_seek(file, dataoff - foffset))
2025 		goto end_coredump;
2026 
2027 	for (vma = first_vma(current, gate_vma); vma != NULL;
2028 			vma = next_vma(vma, gate_vma)) {
2029 		unsigned long addr;
2030 		unsigned long end;
2031 
2032 		end = vma->vm_start + vma_dump_size(vma, mm_flags);
2033 
2034 		for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) {
2035 			struct page *page;
2036 			int stop;
2037 
2038 			page = get_dump_page(addr);
2039 			if (page) {
2040 				void *kaddr = kmap(page);
2041 				stop = ((size += PAGE_SIZE) > limit) ||
2042 					!dump_write(file, kaddr, PAGE_SIZE);
2043 				kunmap(page);
2044 				page_cache_release(page);
2045 			} else
2046 				stop = !dump_seek(file, PAGE_SIZE);
2047 			if (stop)
2048 				goto end_coredump;
2049 		}
2050 	}
2051 
2052 #ifdef ELF_CORE_WRITE_EXTRA_DATA
2053 	ELF_CORE_WRITE_EXTRA_DATA;
2054 #endif
2055 
2056 end_coredump:
2057 	set_fs(fs);
2058 
2059 cleanup:
2060 	free_note_info(&info);
2061 	kfree(elf);
2062 out:
2063 	return has_dumped;
2064 }
2065 
2066 #endif		/* USE_ELF_CORE_DUMP */
2067 
2068 static int __init init_elf_binfmt(void)
2069 {
2070 	return register_binfmt(&elf_format);
2071 }
2072 
2073 static void __exit exit_elf_binfmt(void)
2074 {
2075 	/* Remove the COFF and ELF loaders. */
2076 	unregister_binfmt(&elf_format);
2077 }
2078 
2079 core_initcall(init_elf_binfmt);
2080 module_exit(exit_elf_binfmt);
2081 MODULE_LICENSE("GPL");
2082