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/vmalloc.h>
  31#include <linux/security.h>
  32#include <linux/random.h>
  33#include <linux/elf.h>
  34#include <linux/elf-randomize.h>
  35#include <linux/utsname.h>
  36#include <linux/coredump.h>
  37#include <linux/sched.h>
 
 
 
 
 
 
  38#include <linux/dax.h>
  39#include <linux/uaccess.h>
  40#include <asm/param.h>
  41#include <asm/page.h>
  42
 
 
 
 
  43#ifndef user_long_t
  44#define user_long_t long
  45#endif
  46#ifndef user_siginfo_t
  47#define user_siginfo_t siginfo_t
  48#endif
  49
 
 
 
 
 
  50static int load_elf_binary(struct linux_binprm *bprm);
  51static unsigned long elf_map(struct file *, unsigned long, struct elf_phdr *,
  52				int, int, unsigned long);
  53
  54#ifdef CONFIG_USELIB
  55static int load_elf_library(struct file *);
  56#else
  57#define load_elf_library NULL
  58#endif
  59
  60/*
  61 * If we don't support core dumping, then supply a NULL so we
  62 * don't even try.
  63 */
  64#ifdef CONFIG_ELF_CORE
  65static int elf_core_dump(struct coredump_params *cprm);
  66#else
  67#define elf_core_dump	NULL
  68#endif
  69
  70#if ELF_EXEC_PAGESIZE > PAGE_SIZE
  71#define ELF_MIN_ALIGN	ELF_EXEC_PAGESIZE
  72#else
  73#define ELF_MIN_ALIGN	PAGE_SIZE
  74#endif
  75
  76#ifndef ELF_CORE_EFLAGS
  77#define ELF_CORE_EFLAGS	0
  78#endif
  79
  80#define ELF_PAGESTART(_v) ((_v) & ~(unsigned long)(ELF_MIN_ALIGN-1))
  81#define ELF_PAGEOFFSET(_v) ((_v) & (ELF_MIN_ALIGN-1))
  82#define ELF_PAGEALIGN(_v) (((_v) + ELF_MIN_ALIGN - 1) & ~(ELF_MIN_ALIGN - 1))
  83
  84static struct linux_binfmt elf_format = {
  85	.module		= THIS_MODULE,
  86	.load_binary	= load_elf_binary,
  87	.load_shlib	= load_elf_library,
 
  88	.core_dump	= elf_core_dump,
  89	.min_coredump	= ELF_EXEC_PAGESIZE,
 
  90};
  91
  92#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
  93
  94static int set_brk(unsigned long start, unsigned long end)
  95{
  96	start = ELF_PAGEALIGN(start);
  97	end = ELF_PAGEALIGN(end);
  98	if (end > start) {
  99		int error = vm_brk(start, end - start);
 
 
 
 
 
 
 100		if (error)
 101			return error;
 102	}
 103	current->mm->start_brk = current->mm->brk = end;
 104	return 0;
 105}
 106
 107/* We need to explicitly zero any fractional pages
 108   after the data section (i.e. bss).  This would
 109   contain the junk from the file that should not
 110   be in memory
 111 */
 112static int padzero(unsigned long elf_bss)
 113{
 114	unsigned long nbyte;
 115
 116	nbyte = ELF_PAGEOFFSET(elf_bss);
 117	if (nbyte) {
 118		nbyte = ELF_MIN_ALIGN - nbyte;
 119		if (clear_user((void __user *) elf_bss, nbyte))
 120			return -EFAULT;
 121	}
 122	return 0;
 123}
 124
 125/* Let's use some macros to make this stack manipulation a little clearer */
 126#ifdef CONFIG_STACK_GROWSUP
 127#define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) + (items))
 128#define STACK_ROUND(sp, items) \
 129	((15 + (unsigned long) ((sp) + (items))) &~ 15UL)
 130#define STACK_ALLOC(sp, len) ({ \
 131	elf_addr_t __user *old_sp = (elf_addr_t __user *)sp; sp += len; \
 132	old_sp; })
 133#else
 134#define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) - (items))
 135#define STACK_ROUND(sp, items) \
 136	(((unsigned long) (sp - items)) &~ 15UL)
 137#define STACK_ALLOC(sp, len) ({ sp -= len ; sp; })
 138#endif
 139
 140#ifndef ELF_BASE_PLATFORM
 141/*
 142 * AT_BASE_PLATFORM indicates the "real" hardware/microarchitecture.
 143 * If the arch defines ELF_BASE_PLATFORM (in asm/elf.h), the value
 144 * will be copied to the user stack in the same manner as AT_PLATFORM.
 145 */
 146#define ELF_BASE_PLATFORM NULL
 147#endif
 148
 149static int
 150create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
 151		unsigned long load_addr, unsigned long interp_load_addr)
 
 152{
 
 153	unsigned long p = bprm->p;
 154	int argc = bprm->argc;
 155	int envc = bprm->envc;
 156	elf_addr_t __user *argv;
 157	elf_addr_t __user *envp;
 158	elf_addr_t __user *sp;
 159	elf_addr_t __user *u_platform;
 160	elf_addr_t __user *u_base_platform;
 161	elf_addr_t __user *u_rand_bytes;
 162	const char *k_platform = ELF_PLATFORM;
 163	const char *k_base_platform = ELF_BASE_PLATFORM;
 164	unsigned char k_rand_bytes[16];
 165	int items;
 166	elf_addr_t *elf_info;
 167	int ei_index = 0;
 
 168	const struct cred *cred = current_cred();
 169	struct vm_area_struct *vma;
 170
 171	/*
 172	 * In some cases (e.g. Hyper-Threading), we want to avoid L1
 173	 * evictions by the processes running on the same package. One
 174	 * thing we can do is to shuffle the initial stack for them.
 175	 */
 176
 177	p = arch_align_stack(p);
 178
 179	/*
 180	 * If this architecture has a platform capability string, copy it
 181	 * to userspace.  In some cases (Sparc), this info is impossible
 182	 * for userspace to get any other way, in others (i386) it is
 183	 * merely difficult.
 184	 */
 185	u_platform = NULL;
 186	if (k_platform) {
 187		size_t len = strlen(k_platform) + 1;
 188
 189		u_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
 190		if (__copy_to_user(u_platform, k_platform, len))
 191			return -EFAULT;
 192	}
 193
 194	/*
 195	 * If this architecture has a "base" platform capability
 196	 * string, copy it to userspace.
 197	 */
 198	u_base_platform = NULL;
 199	if (k_base_platform) {
 200		size_t len = strlen(k_base_platform) + 1;
 201
 202		u_base_platform = (elf_addr_t __user *)STACK_ALLOC(p, len);
 203		if (__copy_to_user(u_base_platform, k_base_platform, len))
 204			return -EFAULT;
 205	}
 206
 207	/*
 208	 * Generate 16 random bytes for userspace PRNG seeding.
 209	 */
 210	get_random_bytes(k_rand_bytes, sizeof(k_rand_bytes));
 211	u_rand_bytes = (elf_addr_t __user *)
 212		       STACK_ALLOC(p, sizeof(k_rand_bytes));
 213	if (__copy_to_user(u_rand_bytes, k_rand_bytes, sizeof(k_rand_bytes)))
 214		return -EFAULT;
 215
 216	/* Create the ELF interpreter info */
 217	elf_info = (elf_addr_t *)current->mm->saved_auxv;
 218	/* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */
 219#define NEW_AUX_ENT(id, val) \
 220	do { \
 221		elf_info[ei_index++] = id; \
 222		elf_info[ei_index++] = val; \
 223	} while (0)
 224
 225#ifdef ARCH_DLINFO
 226	/* 
 227	 * ARCH_DLINFO must come first so PPC can do its special alignment of
 228	 * AUXV.
 229	 * update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT() in
 230	 * ARCH_DLINFO changes
 231	 */
 232	ARCH_DLINFO;
 233#endif
 234	NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
 235	NEW_AUX_ENT(AT_PAGESZ, ELF_EXEC_PAGESIZE);
 236	NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
 237	NEW_AUX_ENT(AT_PHDR, load_addr + exec->e_phoff);
 238	NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
 239	NEW_AUX_ENT(AT_PHNUM, exec->e_phnum);
 240	NEW_AUX_ENT(AT_BASE, interp_load_addr);
 241	NEW_AUX_ENT(AT_FLAGS, 0);
 242	NEW_AUX_ENT(AT_ENTRY, exec->e_entry);
 
 
 243	NEW_AUX_ENT(AT_UID, from_kuid_munged(cred->user_ns, cred->uid));
 244	NEW_AUX_ENT(AT_EUID, from_kuid_munged(cred->user_ns, cred->euid));
 245	NEW_AUX_ENT(AT_GID, from_kgid_munged(cred->user_ns, cred->gid));
 246	NEW_AUX_ENT(AT_EGID, from_kgid_munged(cred->user_ns, cred->egid));
 247 	NEW_AUX_ENT(AT_SECURE, security_bprm_secureexec(bprm));
 248	NEW_AUX_ENT(AT_RANDOM, (elf_addr_t)(unsigned long)u_rand_bytes);
 249#ifdef ELF_HWCAP2
 250	NEW_AUX_ENT(AT_HWCAP2, ELF_HWCAP2);
 251#endif
 252	NEW_AUX_ENT(AT_EXECFN, bprm->exec);
 253	if (k_platform) {
 254		NEW_AUX_ENT(AT_PLATFORM,
 255			    (elf_addr_t)(unsigned long)u_platform);
 256	}
 257	if (k_base_platform) {
 258		NEW_AUX_ENT(AT_BASE_PLATFORM,
 259			    (elf_addr_t)(unsigned long)u_base_platform);
 260	}
 261	if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
 262		NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
 263	}
 264#undef NEW_AUX_ENT
 265	/* AT_NULL is zero; clear the rest too */
 266	memset(&elf_info[ei_index], 0,
 267	       sizeof current->mm->saved_auxv - ei_index * sizeof elf_info[0]);
 268
 269	/* And advance past the AT_NULL entry.  */
 270	ei_index += 2;
 271
 
 272	sp = STACK_ADD(p, ei_index);
 273
 274	items = (argc + 1) + (envc + 1) + 1;
 275	bprm->p = STACK_ROUND(sp, items);
 276
 277	/* Point sp at the lowest address on the stack */
 278#ifdef CONFIG_STACK_GROWSUP
 279	sp = (elf_addr_t __user *)bprm->p - items - ei_index;
 280	bprm->exec = (unsigned long)sp; /* XXX: PARISC HACK */
 281#else
 282	sp = (elf_addr_t __user *)bprm->p;
 283#endif
 284
 285
 286	/*
 287	 * Grow the stack manually; some architectures have a limit on how
 288	 * far ahead a user-space access may be in order to grow the stack.
 289	 */
 290	vma = find_extend_vma(current->mm, bprm->p);
 
 
 
 291	if (!vma)
 292		return -EFAULT;
 293
 294	/* Now, let's put argc (and argv, envp if appropriate) on the stack */
 295	if (__put_user(argc, sp++))
 296		return -EFAULT;
 297	argv = sp;
 298	envp = argv + argc + 1;
 299
 300	/* Populate argv and envp */
 301	p = current->mm->arg_end = current->mm->arg_start;
 302	while (argc-- > 0) {
 303		size_t len;
 304		if (__put_user((elf_addr_t)p, argv++))
 305			return -EFAULT;
 306		len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
 307		if (!len || len > MAX_ARG_STRLEN)
 308			return -EINVAL;
 309		p += len;
 310	}
 311	if (__put_user(0, argv))
 312		return -EFAULT;
 313	current->mm->arg_end = current->mm->env_start = p;
 
 
 
 314	while (envc-- > 0) {
 315		size_t len;
 316		if (__put_user((elf_addr_t)p, envp++))
 317			return -EFAULT;
 318		len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
 319		if (!len || len > MAX_ARG_STRLEN)
 320			return -EINVAL;
 321		p += len;
 322	}
 323	if (__put_user(0, envp))
 324		return -EFAULT;
 325	current->mm->env_end = p;
 326
 327	/* Put the elf_info on the stack in the right place.  */
 328	sp = (elf_addr_t __user *)envp + 1;
 329	if (copy_to_user(sp, elf_info, ei_index * sizeof(elf_addr_t)))
 330		return -EFAULT;
 331	return 0;
 332}
 333
 334#ifndef elf_map
 335
 336static unsigned long elf_map(struct file *filep, unsigned long addr,
 337		struct elf_phdr *eppnt, int prot, int type,
 338		unsigned long total_size)
 339{
 340	unsigned long map_addr;
 341	unsigned long size = eppnt->p_filesz + ELF_PAGEOFFSET(eppnt->p_vaddr);
 342	unsigned long off = eppnt->p_offset - ELF_PAGEOFFSET(eppnt->p_vaddr);
 343	addr = ELF_PAGESTART(addr);
 344	size = ELF_PAGEALIGN(size);
 345
 346	/* mmap() will return -EINVAL if given a zero size, but a
 347	 * segment with zero filesize is perfectly valid */
 348	if (!size)
 349		return addr;
 350
 351	/*
 352	* total_size is the size of the ELF (interpreter) image.
 353	* The _first_ mmap needs to know the full size, otherwise
 354	* randomization might put this image into an overlapping
 355	* position with the ELF binary image. (since size < total_size)
 356	* So we first map the 'big' image - and unmap the remainder at
 357	* the end. (which unmap is needed for ELF images with holes.)
 358	*/
 359	if (total_size) {
 360		total_size = ELF_PAGEALIGN(total_size);
 361		map_addr = vm_mmap(filep, addr, total_size, prot, type, off);
 362		if (!BAD_ADDR(map_addr))
 363			vm_munmap(map_addr+size, total_size-size);
 364	} else
 365		map_addr = vm_mmap(filep, addr, size, prot, type, off);
 366
 
 
 
 
 
 367	return(map_addr);
 368}
 369
 370#endif /* !elf_map */
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 371
 372static unsigned long total_mapping_size(struct elf_phdr *cmds, int nr)
 373{
 374	int i, first_idx = -1, last_idx = -1;
 
 375
 376	for (i = 0; i < nr; i++) {
 377		if (cmds[i].p_type == PT_LOAD) {
 378			last_idx = i;
 379			if (first_idx == -1)
 380				first_idx = i;
 
 
 
 381		}
 382	}
 383	if (first_idx == -1)
 384		return 0;
 385
 386	return cmds[last_idx].p_vaddr + cmds[last_idx].p_memsz -
 387				ELF_PAGESTART(cmds[first_idx].p_vaddr);
 388}
 389
 390/**
 391 * load_elf_phdrs() - load ELF program headers
 392 * @elf_ex:   ELF header of the binary whose program headers should be loaded
 393 * @elf_file: the opened ELF binary file
 394 *
 395 * Loads ELF program headers from the binary file elf_file, which has the ELF
 396 * header pointed to by elf_ex, into a newly allocated array. The caller is
 397 * responsible for freeing the allocated data. Returns an ERR_PTR upon failure.
 398 */
 399static struct elf_phdr *load_elf_phdrs(struct elfhdr *elf_ex,
 400				       struct file *elf_file)
 401{
 402	struct elf_phdr *elf_phdata = NULL;
 403	int retval, size, err = -1;
 
 404
 405	/*
 406	 * If the size of this structure has changed, then punt, since
 407	 * we will be doing the wrong thing.
 408	 */
 409	if (elf_ex->e_phentsize != sizeof(struct elf_phdr))
 410		goto out;
 411
 412	/* Sanity check the number of program headers... */
 413	if (elf_ex->e_phnum < 1 ||
 414		elf_ex->e_phnum > 65536U / sizeof(struct elf_phdr))
 415		goto out;
 416
 417	/* ...and their total size. */
 418	size = sizeof(struct elf_phdr) * elf_ex->e_phnum;
 419	if (size > ELF_MIN_ALIGN)
 420		goto out;
 421
 422	elf_phdata = kmalloc(size, GFP_KERNEL);
 423	if (!elf_phdata)
 424		goto out;
 425
 426	/* Read in the program headers */
 427	retval = kernel_read(elf_file, elf_ex->e_phoff,
 428			     (char *)elf_phdata, size);
 429	if (retval != size) {
 430		err = (retval < 0) ? retval : -EIO;
 431		goto out;
 432	}
 433
 434	/* Success! */
 435	err = 0;
 436out:
 437	if (err) {
 438		kfree(elf_phdata);
 439		elf_phdata = NULL;
 440	}
 441	return elf_phdata;
 442}
 443
 444#ifndef CONFIG_ARCH_BINFMT_ELF_STATE
 445
 446/**
 447 * struct arch_elf_state - arch-specific ELF loading state
 448 *
 449 * This structure is used to preserve architecture specific data during
 450 * the loading of an ELF file, throughout the checking of architecture
 451 * specific ELF headers & through to the point where the ELF load is
 452 * known to be proceeding (ie. SET_PERSONALITY).
 453 *
 454 * This implementation is a dummy for architectures which require no
 455 * specific state.
 456 */
 457struct arch_elf_state {
 458};
 459
 460#define INIT_ARCH_ELF_STATE {}
 461
 462/**
 463 * arch_elf_pt_proc() - check a PT_LOPROC..PT_HIPROC ELF program header
 464 * @ehdr:	The main ELF header
 465 * @phdr:	The program header to check
 466 * @elf:	The open ELF file
 467 * @is_interp:	True if the phdr is from the interpreter of the ELF being
 468 *		loaded, else false.
 469 * @state:	Architecture-specific state preserved throughout the process
 470 *		of loading the ELF.
 471 *
 472 * Inspects the program header phdr to validate its correctness and/or
 473 * suitability for the system. Called once per ELF program header in the
 474 * range PT_LOPROC to PT_HIPROC, for both the ELF being loaded and its
 475 * interpreter.
 476 *
 477 * Return: Zero to proceed with the ELF load, non-zero to fail the ELF load
 478 *         with that return code.
 479 */
 480static inline int arch_elf_pt_proc(struct elfhdr *ehdr,
 481				   struct elf_phdr *phdr,
 482				   struct file *elf, bool is_interp,
 483				   struct arch_elf_state *state)
 484{
 485	/* Dummy implementation, always proceed */
 486	return 0;
 487}
 488
 489/**
 490 * arch_check_elf() - check an ELF executable
 491 * @ehdr:	The main ELF header
 492 * @has_interp:	True if the ELF has an interpreter, else false.
 493 * @interp_ehdr: The interpreter's ELF header
 494 * @state:	Architecture-specific state preserved throughout the process
 495 *		of loading the ELF.
 496 *
 497 * Provides a final opportunity for architecture code to reject the loading
 498 * of the ELF & cause an exec syscall to return an error. This is called after
 499 * all program headers to be checked by arch_elf_pt_proc have been.
 500 *
 501 * Return: Zero to proceed with the ELF load, non-zero to fail the ELF load
 502 *         with that return code.
 503 */
 504static inline int arch_check_elf(struct elfhdr *ehdr, bool has_interp,
 505				 struct elfhdr *interp_ehdr,
 506				 struct arch_elf_state *state)
 507{
 508	/* Dummy implementation, always proceed */
 509	return 0;
 510}
 511
 512#endif /* !CONFIG_ARCH_BINFMT_ELF_STATE */
 513
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 514/* This is much more generalized than the library routine read function,
 515   so we keep this separate.  Technically the library read function
 516   is only provided so that we can read a.out libraries that have
 517   an ELF header */
 518
 519static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
 520		struct file *interpreter, unsigned long *interp_map_addr,
 521		unsigned long no_base, struct elf_phdr *interp_elf_phdata)
 
 522{
 523	struct elf_phdr *eppnt;
 524	unsigned long load_addr = 0;
 525	int load_addr_set = 0;
 526	unsigned long last_bss = 0, elf_bss = 0;
 
 527	unsigned long error = ~0UL;
 528	unsigned long total_size;
 529	int i;
 530
 531	/* First of all, some simple consistency checks */
 532	if (interp_elf_ex->e_type != ET_EXEC &&
 533	    interp_elf_ex->e_type != ET_DYN)
 534		goto out;
 535	if (!elf_check_arch(interp_elf_ex))
 
 536		goto out;
 537	if (!interpreter->f_op->mmap)
 538		goto out;
 539
 540	total_size = total_mapping_size(interp_elf_phdata,
 541					interp_elf_ex->e_phnum);
 542	if (!total_size) {
 543		error = -EINVAL;
 544		goto out;
 545	}
 546
 547	eppnt = interp_elf_phdata;
 548	for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
 549		if (eppnt->p_type == PT_LOAD) {
 550			int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
 551			int elf_prot = 0;
 
 552			unsigned long vaddr = 0;
 553			unsigned long k, map_addr;
 554
 555			if (eppnt->p_flags & PF_R)
 556		    		elf_prot = PROT_READ;
 557			if (eppnt->p_flags & PF_W)
 558				elf_prot |= PROT_WRITE;
 559			if (eppnt->p_flags & PF_X)
 560				elf_prot |= PROT_EXEC;
 561			vaddr = eppnt->p_vaddr;
 562			if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
 563				elf_type |= MAP_FIXED;
 564			else if (no_base && interp_elf_ex->e_type == ET_DYN)
 565				load_addr = -vaddr;
 566
 567			map_addr = elf_map(interpreter, load_addr + vaddr,
 568					eppnt, elf_prot, elf_type, total_size);
 569			total_size = 0;
 570			if (!*interp_map_addr)
 571				*interp_map_addr = map_addr;
 572			error = map_addr;
 573			if (BAD_ADDR(map_addr))
 574				goto out;
 575
 576			if (!load_addr_set &&
 577			    interp_elf_ex->e_type == ET_DYN) {
 578				load_addr = map_addr - ELF_PAGESTART(vaddr);
 579				load_addr_set = 1;
 580			}
 581
 582			/*
 583			 * Check to see if the section's size will overflow the
 584			 * allowed task size. Note that p_filesz must always be
 585			 * <= p_memsize so it's only necessary to check p_memsz.
 586			 */
 587			k = load_addr + eppnt->p_vaddr;
 588			if (BAD_ADDR(k) ||
 589			    eppnt->p_filesz > eppnt->p_memsz ||
 590			    eppnt->p_memsz > TASK_SIZE ||
 591			    TASK_SIZE - eppnt->p_memsz < k) {
 592				error = -ENOMEM;
 593				goto out;
 594			}
 595
 596			/*
 597			 * Find the end of the file mapping for this phdr, and
 598			 * keep track of the largest address we see for this.
 599			 */
 600			k = load_addr + eppnt->p_vaddr + eppnt->p_filesz;
 601			if (k > elf_bss)
 602				elf_bss = k;
 603
 604			/*
 605			 * Do the same thing for the memory mapping - between
 606			 * elf_bss and last_bss is the bss section.
 607			 */
 608			k = load_addr + eppnt->p_vaddr + eppnt->p_memsz;
 609			if (k > last_bss)
 610				last_bss = k;
 
 
 611		}
 612	}
 613
 614	/*
 615	 * Now fill out the bss section: first pad the last page from
 616	 * the file up to the page boundary, and zero it from elf_bss
 617	 * up to the end of the page.
 618	 */
 619	if (padzero(elf_bss)) {
 620		error = -EFAULT;
 621		goto out;
 622	}
 623	/*
 624	 * Next, align both the file and mem bss up to the page size,
 625	 * since this is where elf_bss was just zeroed up to, and where
 626	 * last_bss will end after the vm_brk() below.
 627	 */
 628	elf_bss = ELF_PAGEALIGN(elf_bss);
 629	last_bss = ELF_PAGEALIGN(last_bss);
 630	/* Finally, if there is still more bss to allocate, do it. */
 631	if (last_bss > elf_bss) {
 632		error = vm_brk(elf_bss, last_bss - elf_bss);
 
 633		if (error)
 634			goto out;
 635	}
 636
 637	error = load_addr;
 638out:
 639	return error;
 640}
 641
 642/*
 643 * These are the functions used to load ELF style executables and shared
 644 * libraries.  There is no binary dependent code anywhere else.
 645 */
 646
 647#ifndef STACK_RND_MASK
 648#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))	/* 8MB of VA */
 649#endif
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 650
 651static unsigned long randomize_stack_top(unsigned long stack_top)
 652{
 653	unsigned long random_variable = 0;
 
 654
 655	if ((current->flags & PF_RANDOMIZE) &&
 656		!(current->personality & ADDR_NO_RANDOMIZE)) {
 657		random_variable = get_random_long();
 658		random_variable &= STACK_RND_MASK;
 659		random_variable <<= PAGE_SHIFT;
 660	}
 661#ifdef CONFIG_STACK_GROWSUP
 662	return PAGE_ALIGN(stack_top) + random_variable;
 663#else
 664	return PAGE_ALIGN(stack_top) - random_variable;
 665#endif
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 666}
 667
 668static int load_elf_binary(struct linux_binprm *bprm)
 669{
 670	struct file *interpreter = NULL; /* to shut gcc up */
 671 	unsigned long load_addr = 0, load_bias = 0;
 672	int load_addr_set = 0;
 673	char * elf_interpreter = NULL;
 674	unsigned long error;
 675	struct elf_phdr *elf_ppnt, *elf_phdata, *interp_elf_phdata = NULL;
 
 676	unsigned long elf_bss, elf_brk;
 
 677	int retval, i;
 678	unsigned long elf_entry;
 
 679	unsigned long interp_load_addr = 0;
 680	unsigned long start_code, end_code, start_data, end_data;
 681	unsigned long reloc_func_desc __maybe_unused = 0;
 682	int executable_stack = EXSTACK_DEFAULT;
 683	struct pt_regs *regs = current_pt_regs();
 684	struct {
 685		struct elfhdr elf_ex;
 686		struct elfhdr interp_elf_ex;
 687	} *loc;
 688	struct arch_elf_state arch_state = INIT_ARCH_ELF_STATE;
 689
 690	loc = kmalloc(sizeof(*loc), GFP_KERNEL);
 691	if (!loc) {
 692		retval = -ENOMEM;
 693		goto out_ret;
 694	}
 695	
 696	/* Get the exec-header */
 697	loc->elf_ex = *((struct elfhdr *)bprm->buf);
 698
 699	retval = -ENOEXEC;
 700	/* First of all, some simple consistency checks */
 701	if (memcmp(loc->elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
 702		goto out;
 703
 704	if (loc->elf_ex.e_type != ET_EXEC && loc->elf_ex.e_type != ET_DYN)
 705		goto out;
 706	if (!elf_check_arch(&loc->elf_ex))
 
 
 707		goto out;
 708	if (!bprm->file->f_op->mmap)
 709		goto out;
 710
 711	elf_phdata = load_elf_phdrs(&loc->elf_ex, bprm->file);
 712	if (!elf_phdata)
 713		goto out;
 714
 715	elf_ppnt = elf_phdata;
 716	elf_bss = 0;
 717	elf_brk = 0;
 718
 719	start_code = ~0UL;
 720	end_code = 0;
 721	start_data = 0;
 722	end_data = 0;
 723
 724	for (i = 0; i < loc->elf_ex.e_phnum; i++) {
 725		if (elf_ppnt->p_type == PT_INTERP) {
 726			/* This is the program interpreter used for
 727			 * shared libraries - for now assume that this
 728			 * is an a.out format binary
 729			 */
 730			retval = -ENOEXEC;
 731			if (elf_ppnt->p_filesz > PATH_MAX || 
 732			    elf_ppnt->p_filesz < 2)
 733				goto out_free_ph;
 734
 735			retval = -ENOMEM;
 736			elf_interpreter = kmalloc(elf_ppnt->p_filesz,
 737						  GFP_KERNEL);
 738			if (!elf_interpreter)
 739				goto out_free_ph;
 740
 741			retval = kernel_read(bprm->file, elf_ppnt->p_offset,
 742					     elf_interpreter,
 743					     elf_ppnt->p_filesz);
 744			if (retval != elf_ppnt->p_filesz) {
 745				if (retval >= 0)
 746					retval = -EIO;
 747				goto out_free_interp;
 748			}
 749			/* make sure path is NULL terminated */
 750			retval = -ENOEXEC;
 751			if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
 752				goto out_free_interp;
 753
 754			interpreter = open_exec(elf_interpreter);
 755			retval = PTR_ERR(interpreter);
 756			if (IS_ERR(interpreter))
 757				goto out_free_interp;
 758
 759			/*
 760			 * If the binary is not readable then enforce
 761			 * mm->dumpable = 0 regardless of the interpreter's
 762			 * permissions.
 763			 */
 764			would_dump(bprm, interpreter);
 765
 766			/* Get the exec headers */
 767			retval = kernel_read(interpreter, 0,
 768					     (void *)&loc->interp_elf_ex,
 769					     sizeof(loc->interp_elf_ex));
 770			if (retval != sizeof(loc->interp_elf_ex)) {
 771				if (retval >= 0)
 772					retval = -EIO;
 773				goto out_free_dentry;
 774			}
 775
 776			break;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 777		}
 778		elf_ppnt++;
 
 
 
 
 
 
 
 
 
 
 
 779	}
 780
 781	elf_ppnt = elf_phdata;
 782	for (i = 0; i < loc->elf_ex.e_phnum; i++, elf_ppnt++)
 783		switch (elf_ppnt->p_type) {
 784		case PT_GNU_STACK:
 785			if (elf_ppnt->p_flags & PF_X)
 786				executable_stack = EXSTACK_ENABLE_X;
 787			else
 788				executable_stack = EXSTACK_DISABLE_X;
 789			break;
 790
 791		case PT_LOPROC ... PT_HIPROC:
 792			retval = arch_elf_pt_proc(&loc->elf_ex, elf_ppnt,
 793						  bprm->file, false,
 794						  &arch_state);
 795			if (retval)
 796				goto out_free_dentry;
 797			break;
 798		}
 799
 800	/* Some simple consistency checks for the interpreter */
 801	if (elf_interpreter) {
 802		retval = -ELIBBAD;
 803		/* Not an ELF interpreter */
 804		if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
 805			goto out_free_dentry;
 806		/* Verify the interpreter has a valid arch */
 807		if (!elf_check_arch(&loc->interp_elf_ex))
 
 808			goto out_free_dentry;
 809
 810		/* Load the interpreter program headers */
 811		interp_elf_phdata = load_elf_phdrs(&loc->interp_elf_ex,
 812						   interpreter);
 813		if (!interp_elf_phdata)
 814			goto out_free_dentry;
 815
 816		/* Pass PT_LOPROC..PT_HIPROC headers to arch code */
 
 817		elf_ppnt = interp_elf_phdata;
 818		for (i = 0; i < loc->interp_elf_ex.e_phnum; i++, elf_ppnt++)
 819			switch (elf_ppnt->p_type) {
 
 
 
 
 820			case PT_LOPROC ... PT_HIPROC:
 821				retval = arch_elf_pt_proc(&loc->interp_elf_ex,
 822							  elf_ppnt, interpreter,
 823							  true, &arch_state);
 824				if (retval)
 825					goto out_free_dentry;
 826				break;
 827			}
 828	}
 829
 
 
 
 
 
 830	/*
 831	 * Allow arch code to reject the ELF at this point, whilst it's
 832	 * still possible to return an error to the code that invoked
 833	 * the exec syscall.
 834	 */
 835	retval = arch_check_elf(&loc->elf_ex,
 836				!!interpreter, &loc->interp_elf_ex,
 837				&arch_state);
 838	if (retval)
 839		goto out_free_dentry;
 840
 841	/* Flush all traces of the currently running executable */
 842	retval = flush_old_exec(bprm);
 843	if (retval)
 844		goto out_free_dentry;
 845
 846	/* Do this immediately, since STACK_TOP as used in setup_arg_pages
 847	   may depend on the personality.  */
 848	SET_PERSONALITY2(loc->elf_ex, &arch_state);
 849	if (elf_read_implies_exec(loc->elf_ex, executable_stack))
 850		current->personality |= READ_IMPLIES_EXEC;
 851
 852	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
 853		current->flags |= PF_RANDOMIZE;
 854
 855	setup_new_exec(bprm);
 856	install_exec_creds(bprm);
 857
 858	/* Do this so that we can load the interpreter, if need be.  We will
 859	   change some of these later */
 860	retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
 861				 executable_stack);
 862	if (retval < 0)
 863		goto out_free_dentry;
 864	
 865	current->mm->start_stack = bprm->p;
 
 
 
 
 
 
 866
 867	/* Now we do a little grungy work by mmapping the ELF image into
 868	   the correct location in memory. */
 869	for(i = 0, elf_ppnt = elf_phdata;
 870	    i < loc->elf_ex.e_phnum; i++, elf_ppnt++) {
 871		int elf_prot = 0, elf_flags;
 872		unsigned long k, vaddr;
 873		unsigned long total_size = 0;
 
 874
 875		if (elf_ppnt->p_type != PT_LOAD)
 876			continue;
 877
 878		if (unlikely (elf_brk > elf_bss)) {
 879			unsigned long nbyte;
 880	            
 881			/* There was a PT_LOAD segment with p_memsz > p_filesz
 882			   before this one. Map anonymous pages, if needed,
 883			   and clear the area.  */
 884			retval = set_brk(elf_bss + load_bias,
 885					 elf_brk + load_bias);
 
 886			if (retval)
 887				goto out_free_dentry;
 888			nbyte = ELF_PAGEOFFSET(elf_bss);
 889			if (nbyte) {
 890				nbyte = ELF_MIN_ALIGN - nbyte;
 891				if (nbyte > elf_brk - elf_bss)
 892					nbyte = elf_brk - elf_bss;
 893				if (clear_user((void __user *)elf_bss +
 894							load_bias, nbyte)) {
 895					/*
 896					 * This bss-zeroing can fail if the ELF
 897					 * file specifies odd protections. So
 898					 * we don't check the return value
 899					 */
 900				}
 901			}
 902		}
 903
 904		if (elf_ppnt->p_flags & PF_R)
 905			elf_prot |= PROT_READ;
 906		if (elf_ppnt->p_flags & PF_W)
 907			elf_prot |= PROT_WRITE;
 908		if (elf_ppnt->p_flags & PF_X)
 909			elf_prot |= PROT_EXEC;
 910
 911		elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE;
 912
 913		vaddr = elf_ppnt->p_vaddr;
 914		if (loc->elf_ex.e_type == ET_EXEC || load_addr_set) {
 
 
 
 
 
 
 915			elf_flags |= MAP_FIXED;
 916		} else if (loc->elf_ex.e_type == ET_DYN) {
 917			/* Try and get dynamic programs out of the way of the
 918			 * default mmap base, as well as whatever program they
 919			 * might try to exec.  This is because the brk will
 920			 * follow the loader, and is not movable.  */
 921			load_bias = ELF_ET_DYN_BASE - vaddr;
 922			if (current->flags & PF_RANDOMIZE)
 923				load_bias += arch_mmap_rnd();
 924			load_bias = ELF_PAGESTART(load_bias);
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 925			total_size = total_mapping_size(elf_phdata,
 926							loc->elf_ex.e_phnum);
 927			if (!total_size) {
 928				retval = -EINVAL;
 929				goto out_free_dentry;
 930			}
 931		}
 932
 933		error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
 934				elf_prot, elf_flags, total_size);
 935		if (BAD_ADDR(error)) {
 936			retval = IS_ERR((void *)error) ?
 937				PTR_ERR((void*)error) : -EINVAL;
 938			goto out_free_dentry;
 939		}
 940
 941		if (!load_addr_set) {
 942			load_addr_set = 1;
 943			load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset);
 944			if (loc->elf_ex.e_type == ET_DYN) {
 945				load_bias += error -
 946				             ELF_PAGESTART(load_bias + vaddr);
 947				load_addr += load_bias;
 948				reloc_func_desc = load_bias;
 949			}
 950		}
 
 
 
 
 
 
 
 
 
 
 
 951		k = elf_ppnt->p_vaddr;
 952		if (k < start_code)
 953			start_code = k;
 954		if (start_data < k)
 955			start_data = k;
 956
 957		/*
 958		 * Check to see if the section's size will overflow the
 959		 * allowed task size. Note that p_filesz must always be
 960		 * <= p_memsz so it is only necessary to check p_memsz.
 961		 */
 962		if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
 963		    elf_ppnt->p_memsz > TASK_SIZE ||
 964		    TASK_SIZE - elf_ppnt->p_memsz < k) {
 965			/* set_brk can never work. Avoid overflows. */
 966			retval = -EINVAL;
 967			goto out_free_dentry;
 968		}
 969
 970		k = elf_ppnt->p_vaddr + elf_ppnt->p_filesz;
 971
 972		if (k > elf_bss)
 973			elf_bss = k;
 974		if ((elf_ppnt->p_flags & PF_X) && end_code < k)
 975			end_code = k;
 976		if (end_data < k)
 977			end_data = k;
 978		k = elf_ppnt->p_vaddr + elf_ppnt->p_memsz;
 979		if (k > elf_brk)
 
 980			elf_brk = k;
 
 981	}
 982
 983	loc->elf_ex.e_entry += load_bias;
 
 984	elf_bss += load_bias;
 985	elf_brk += load_bias;
 986	start_code += load_bias;
 987	end_code += load_bias;
 988	start_data += load_bias;
 989	end_data += load_bias;
 990
 991	/* Calling set_brk effectively mmaps the pages that we need
 992	 * for the bss and break sections.  We must do this before
 993	 * mapping in the interpreter, to make sure it doesn't wind
 994	 * up getting placed where the bss needs to go.
 995	 */
 996	retval = set_brk(elf_bss, elf_brk);
 997	if (retval)
 998		goto out_free_dentry;
 999	if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) {
1000		retval = -EFAULT; /* Nobody gets to see this, but.. */
1001		goto out_free_dentry;
1002	}
1003
1004	if (elf_interpreter) {
1005		unsigned long interp_map_addr = 0;
1006
1007		elf_entry = load_elf_interp(&loc->interp_elf_ex,
1008					    interpreter,
1009					    &interp_map_addr,
1010					    load_bias, interp_elf_phdata);
1011		if (!IS_ERR((void *)elf_entry)) {
1012			/*
1013			 * load_elf_interp() returns relocation
1014			 * adjustment
1015			 */
1016			interp_load_addr = elf_entry;
1017			elf_entry += loc->interp_elf_ex.e_entry;
1018		}
1019		if (BAD_ADDR(elf_entry)) {
1020			retval = IS_ERR((void *)elf_entry) ?
1021					(int)elf_entry : -EINVAL;
1022			goto out_free_dentry;
1023		}
1024		reloc_func_desc = interp_load_addr;
1025
1026		allow_write_access(interpreter);
1027		fput(interpreter);
1028		kfree(elf_interpreter);
 
 
1029	} else {
1030		elf_entry = loc->elf_ex.e_entry;
1031		if (BAD_ADDR(elf_entry)) {
1032			retval = -EINVAL;
1033			goto out_free_dentry;
1034		}
1035	}
1036
1037	kfree(interp_elf_phdata);
1038	kfree(elf_phdata);
1039
1040	set_binfmt(&elf_format);
1041
1042#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
1043	retval = arch_setup_additional_pages(bprm, !!elf_interpreter);
1044	if (retval < 0)
1045		goto out;
1046#endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */
1047
1048	retval = create_elf_tables(bprm, &loc->elf_ex,
1049			  load_addr, interp_load_addr);
1050	if (retval < 0)
1051		goto out;
1052	/* N.B. passed_fileno might not be initialized? */
1053	current->mm->end_code = end_code;
1054	current->mm->start_code = start_code;
1055	current->mm->start_data = start_data;
1056	current->mm->end_data = end_data;
1057	current->mm->start_stack = bprm->p;
 
1058
1059	if ((current->flags & PF_RANDOMIZE) && (randomize_va_space > 1)) {
1060		current->mm->brk = current->mm->start_brk =
1061			arch_randomize_brk(current->mm);
 
 
 
 
 
 
 
 
 
 
 
1062#ifdef compat_brk_randomized
1063		current->brk_randomized = 1;
1064#endif
1065	}
1066
1067	if (current->personality & MMAP_PAGE_ZERO) {
1068		/* Why this, you ask???  Well SVr4 maps page 0 as read-only,
1069		   and some applications "depend" upon this behavior.
1070		   Since we do not have the power to recompile these, we
1071		   emulate the SVr4 behavior. Sigh. */
1072		error = vm_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
1073				MAP_FIXED | MAP_PRIVATE, 0);
1074	}
1075
 
1076#ifdef ELF_PLAT_INIT
1077	/*
1078	 * The ABI may specify that certain registers be set up in special
1079	 * ways (on i386 %edx is the address of a DT_FINI function, for
1080	 * example.  In addition, it may also specify (eg, PowerPC64 ELF)
1081	 * that the e_entry field is the address of the function descriptor
1082	 * for the startup routine, rather than the address of the startup
1083	 * routine itself.  This macro performs whatever initialization to
1084	 * the regs structure is required as well as any relocations to the
1085	 * function descriptor entries when executing dynamically links apps.
1086	 */
1087	ELF_PLAT_INIT(regs, reloc_func_desc);
1088#endif
1089
1090	start_thread(regs, elf_entry, bprm->p);
 
1091	retval = 0;
1092out:
1093	kfree(loc);
1094out_ret:
1095	return retval;
1096
1097	/* error cleanup */
1098out_free_dentry:
 
1099	kfree(interp_elf_phdata);
 
1100	allow_write_access(interpreter);
1101	if (interpreter)
1102		fput(interpreter);
1103out_free_interp:
1104	kfree(elf_interpreter);
1105out_free_ph:
1106	kfree(elf_phdata);
1107	goto out;
1108}
1109
1110#ifdef CONFIG_USELIB
1111/* This is really simpleminded and specialized - we are loading an
1112   a.out library that is given an ELF header. */
1113static int load_elf_library(struct file *file)
1114{
1115	struct elf_phdr *elf_phdata;
1116	struct elf_phdr *eppnt;
1117	unsigned long elf_bss, bss, len;
1118	int retval, error, i, j;
1119	struct elfhdr elf_ex;
1120
1121	error = -ENOEXEC;
1122	retval = kernel_read(file, 0, (char *)&elf_ex, sizeof(elf_ex));
1123	if (retval != sizeof(elf_ex))
1124		goto out;
1125
1126	if (memcmp(elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
1127		goto out;
1128
1129	/* First of all, some simple consistency checks */
1130	if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
1131	    !elf_check_arch(&elf_ex) || !file->f_op->mmap)
1132		goto out;
 
 
1133
1134	/* Now read in all of the header information */
1135
1136	j = sizeof(struct elf_phdr) * elf_ex.e_phnum;
1137	/* j < ELF_MIN_ALIGN because elf_ex.e_phnum <= 2 */
1138
1139	error = -ENOMEM;
1140	elf_phdata = kmalloc(j, GFP_KERNEL);
1141	if (!elf_phdata)
1142		goto out;
1143
1144	eppnt = elf_phdata;
1145	error = -ENOEXEC;
1146	retval = kernel_read(file, elf_ex.e_phoff, (char *)eppnt, j);
1147	if (retval != j)
1148		goto out_free_ph;
1149
1150	for (j = 0, i = 0; i<elf_ex.e_phnum; i++)
1151		if ((eppnt + i)->p_type == PT_LOAD)
1152			j++;
1153	if (j != 1)
1154		goto out_free_ph;
1155
1156	while (eppnt->p_type != PT_LOAD)
1157		eppnt++;
1158
1159	/* Now use mmap to map the library into memory. */
1160	error = vm_mmap(file,
1161			ELF_PAGESTART(eppnt->p_vaddr),
1162			(eppnt->p_filesz +
1163			 ELF_PAGEOFFSET(eppnt->p_vaddr)),
1164			PROT_READ | PROT_WRITE | PROT_EXEC,
1165			MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
1166			(eppnt->p_offset -
1167			 ELF_PAGEOFFSET(eppnt->p_vaddr)));
1168	if (error != ELF_PAGESTART(eppnt->p_vaddr))
1169		goto out_free_ph;
1170
1171	elf_bss = eppnt->p_vaddr + eppnt->p_filesz;
1172	if (padzero(elf_bss)) {
1173		error = -EFAULT;
1174		goto out_free_ph;
1175	}
1176
1177	len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr +
1178			    ELF_MIN_ALIGN - 1);
1179	bss = eppnt->p_memsz + eppnt->p_vaddr;
1180	if (bss > len) {
1181		error = vm_brk(len, bss - len);
1182		if (error)
1183			goto out_free_ph;
1184	}
1185	error = 0;
1186
1187out_free_ph:
1188	kfree(elf_phdata);
1189out:
1190	return error;
1191}
1192#endif /* #ifdef CONFIG_USELIB */
1193
1194#ifdef CONFIG_ELF_CORE
1195/*
1196 * ELF core dumper
1197 *
1198 * Modelled on fs/exec.c:aout_core_dump()
1199 * Jeremy Fitzhardinge <jeremy@sw.oz.au>
1200 */
1201
1202/*
1203 * The purpose of always_dump_vma() is to make sure that special kernel mappings
1204 * that are useful for post-mortem analysis are included in every core dump.
1205 * In that way we ensure that the core dump is fully interpretable later
1206 * without matching up the same kernel and hardware config to see what PC values
1207 * meant. These special mappings include - vDSO, vsyscall, and other
1208 * architecture specific mappings
1209 */
1210static bool always_dump_vma(struct vm_area_struct *vma)
1211{
1212	/* Any vsyscall mappings? */
1213	if (vma == get_gate_vma(vma->vm_mm))
1214		return true;
1215
1216	/*
1217	 * Assume that all vmas with a .name op should always be dumped.
1218	 * If this changes, a new vm_ops field can easily be added.
1219	 */
1220	if (vma->vm_ops && vma->vm_ops->name && vma->vm_ops->name(vma))
1221		return true;
1222
1223	/*
1224	 * arch_vma_name() returns non-NULL for special architecture mappings,
1225	 * such as vDSO sections.
1226	 */
1227	if (arch_vma_name(vma))
1228		return true;
1229
1230	return false;
1231}
1232
1233/*
1234 * Decide what to dump of a segment, part, all or none.
1235 */
1236static unsigned long vma_dump_size(struct vm_area_struct *vma,
1237				   unsigned long mm_flags)
1238{
1239#define FILTER(type)	(mm_flags & (1UL << MMF_DUMP_##type))
1240
1241	/* always dump the vdso and vsyscall sections */
1242	if (always_dump_vma(vma))
1243		goto whole;
1244
1245	if (vma->vm_flags & VM_DONTDUMP)
1246		return 0;
1247
1248	/* support for DAX */
1249	if (vma_is_dax(vma)) {
1250		if ((vma->vm_flags & VM_SHARED) && FILTER(DAX_SHARED))
1251			goto whole;
1252		if (!(vma->vm_flags & VM_SHARED) && FILTER(DAX_PRIVATE))
1253			goto whole;
1254		return 0;
1255	}
1256
1257	/* Hugetlb memory check */
1258	if (vma->vm_flags & VM_HUGETLB) {
1259		if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED))
1260			goto whole;
1261		if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE))
1262			goto whole;
1263		return 0;
1264	}
1265
1266	/* Do not dump I/O mapped devices or special mappings */
1267	if (vma->vm_flags & VM_IO)
1268		return 0;
1269
1270	/* By default, dump shared memory if mapped from an anonymous file. */
1271	if (vma->vm_flags & VM_SHARED) {
1272		if (file_inode(vma->vm_file)->i_nlink == 0 ?
1273		    FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
1274			goto whole;
1275		return 0;
1276	}
1277
1278	/* Dump segments that have been written to.  */
1279	if (vma->anon_vma && FILTER(ANON_PRIVATE))
1280		goto whole;
1281	if (vma->vm_file == NULL)
1282		return 0;
1283
1284	if (FILTER(MAPPED_PRIVATE))
1285		goto whole;
1286
1287	/*
1288	 * If this looks like the beginning of a DSO or executable mapping,
1289	 * check for an ELF header.  If we find one, dump the first page to
1290	 * aid in determining what was mapped here.
1291	 */
1292	if (FILTER(ELF_HEADERS) &&
1293	    vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) {
1294		u32 __user *header = (u32 __user *) vma->vm_start;
1295		u32 word;
1296		mm_segment_t fs = get_fs();
1297		/*
1298		 * Doing it this way gets the constant folded by GCC.
1299		 */
1300		union {
1301			u32 cmp;
1302			char elfmag[SELFMAG];
1303		} magic;
1304		BUILD_BUG_ON(SELFMAG != sizeof word);
1305		magic.elfmag[EI_MAG0] = ELFMAG0;
1306		magic.elfmag[EI_MAG1] = ELFMAG1;
1307		magic.elfmag[EI_MAG2] = ELFMAG2;
1308		magic.elfmag[EI_MAG3] = ELFMAG3;
1309		/*
1310		 * Switch to the user "segment" for get_user(),
1311		 * then put back what elf_core_dump() had in place.
1312		 */
1313		set_fs(USER_DS);
1314		if (unlikely(get_user(word, header)))
1315			word = 0;
1316		set_fs(fs);
1317		if (word == magic.cmp)
1318			return PAGE_SIZE;
1319	}
1320
1321#undef	FILTER
1322
1323	return 0;
1324
1325whole:
1326	return vma->vm_end - vma->vm_start;
1327}
1328
1329/* An ELF note in memory */
1330struct memelfnote
1331{
1332	const char *name;
1333	int type;
1334	unsigned int datasz;
1335	void *data;
1336};
1337
1338static int notesize(struct memelfnote *en)
1339{
1340	int sz;
1341
1342	sz = sizeof(struct elf_note);
1343	sz += roundup(strlen(en->name) + 1, 4);
1344	sz += roundup(en->datasz, 4);
1345
1346	return sz;
1347}
1348
1349static int writenote(struct memelfnote *men, struct coredump_params *cprm)
1350{
1351	struct elf_note en;
1352	en.n_namesz = strlen(men->name) + 1;
1353	en.n_descsz = men->datasz;
1354	en.n_type = men->type;
1355
1356	return dump_emit(cprm, &en, sizeof(en)) &&
1357	    dump_emit(cprm, men->name, en.n_namesz) && dump_align(cprm, 4) &&
1358	    dump_emit(cprm, men->data, men->datasz) && dump_align(cprm, 4);
1359}
1360
1361static void fill_elf_header(struct elfhdr *elf, int segs,
1362			    u16 machine, u32 flags)
1363{
1364	memset(elf, 0, sizeof(*elf));
1365
1366	memcpy(elf->e_ident, ELFMAG, SELFMAG);
1367	elf->e_ident[EI_CLASS] = ELF_CLASS;
1368	elf->e_ident[EI_DATA] = ELF_DATA;
1369	elf->e_ident[EI_VERSION] = EV_CURRENT;
1370	elf->e_ident[EI_OSABI] = ELF_OSABI;
1371
1372	elf->e_type = ET_CORE;
1373	elf->e_machine = machine;
1374	elf->e_version = EV_CURRENT;
1375	elf->e_phoff = sizeof(struct elfhdr);
1376	elf->e_flags = flags;
1377	elf->e_ehsize = sizeof(struct elfhdr);
1378	elf->e_phentsize = sizeof(struct elf_phdr);
1379	elf->e_phnum = segs;
1380
1381	return;
1382}
1383
1384static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
1385{
1386	phdr->p_type = PT_NOTE;
1387	phdr->p_offset = offset;
1388	phdr->p_vaddr = 0;
1389	phdr->p_paddr = 0;
1390	phdr->p_filesz = sz;
1391	phdr->p_memsz = 0;
1392	phdr->p_flags = 0;
1393	phdr->p_align = 0;
1394	return;
1395}
1396
1397static void fill_note(struct memelfnote *note, const char *name, int type, 
1398		unsigned int sz, void *data)
1399{
1400	note->name = name;
1401	note->type = type;
1402	note->datasz = sz;
1403	note->data = data;
1404	return;
1405}
1406
1407/*
1408 * fill up all the fields in prstatus from the given task struct, except
1409 * registers which need to be filled up separately.
1410 */
1411static void fill_prstatus(struct elf_prstatus *prstatus,
1412		struct task_struct *p, long signr)
1413{
1414	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
1415	prstatus->pr_sigpend = p->pending.signal.sig[0];
1416	prstatus->pr_sighold = p->blocked.sig[0];
1417	rcu_read_lock();
1418	prstatus->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1419	rcu_read_unlock();
1420	prstatus->pr_pid = task_pid_vnr(p);
1421	prstatus->pr_pgrp = task_pgrp_vnr(p);
1422	prstatus->pr_sid = task_session_vnr(p);
1423	if (thread_group_leader(p)) {
1424		struct task_cputime cputime;
1425
1426		/*
1427		 * This is the record for the group leader.  It shows the
1428		 * group-wide total, not its individual thread total.
1429		 */
1430		thread_group_cputime(p, &cputime);
1431		cputime_to_timeval(cputime.utime, &prstatus->pr_utime);
1432		cputime_to_timeval(cputime.stime, &prstatus->pr_stime);
1433	} else {
1434		cputime_t utime, stime;
1435
1436		task_cputime(p, &utime, &stime);
1437		cputime_to_timeval(utime, &prstatus->pr_utime);
1438		cputime_to_timeval(stime, &prstatus->pr_stime);
1439	}
1440	cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
1441	cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);
 
1442}
1443
1444static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
1445		       struct mm_struct *mm)
1446{
1447	const struct cred *cred;
1448	unsigned int i, len;
1449	
 
1450	/* first copy the parameters from user space */
1451	memset(psinfo, 0, sizeof(struct elf_prpsinfo));
1452
1453	len = mm->arg_end - mm->arg_start;
1454	if (len >= ELF_PRARGSZ)
1455		len = ELF_PRARGSZ-1;
1456	if (copy_from_user(&psinfo->pr_psargs,
1457		           (const char __user *)mm->arg_start, len))
1458		return -EFAULT;
1459	for(i = 0; i < len; i++)
1460		if (psinfo->pr_psargs[i] == 0)
1461			psinfo->pr_psargs[i] = ' ';
1462	psinfo->pr_psargs[len] = 0;
1463
1464	rcu_read_lock();
1465	psinfo->pr_ppid = task_pid_vnr(rcu_dereference(p->real_parent));
1466	rcu_read_unlock();
1467	psinfo->pr_pid = task_pid_vnr(p);
1468	psinfo->pr_pgrp = task_pgrp_vnr(p);
1469	psinfo->pr_sid = task_session_vnr(p);
1470
1471	i = p->state ? ffz(~p->state) + 1 : 0;
 
1472	psinfo->pr_state = i;
1473	psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
1474	psinfo->pr_zomb = psinfo->pr_sname == 'Z';
1475	psinfo->pr_nice = task_nice(p);
1476	psinfo->pr_flag = p->flags;
1477	rcu_read_lock();
1478	cred = __task_cred(p);
1479	SET_UID(psinfo->pr_uid, from_kuid_munged(cred->user_ns, cred->uid));
1480	SET_GID(psinfo->pr_gid, from_kgid_munged(cred->user_ns, cred->gid));
1481	rcu_read_unlock();
1482	strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
1483	
1484	return 0;
1485}
1486
1487static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
1488{
1489	elf_addr_t *auxv = (elf_addr_t *) mm->saved_auxv;
1490	int i = 0;
1491	do
1492		i += 2;
1493	while (auxv[i - 2] != AT_NULL);
1494	fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
1495}
1496
1497static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,
1498		const siginfo_t *siginfo)
1499{
1500	mm_segment_t old_fs = get_fs();
1501	set_fs(KERNEL_DS);
1502	copy_siginfo_to_user((user_siginfo_t __user *) csigdata, siginfo);
1503	set_fs(old_fs);
1504	fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata);
1505}
1506
1507#define MAX_FILE_NOTE_SIZE (4*1024*1024)
1508/*
1509 * Format of NT_FILE note:
1510 *
1511 * long count     -- how many files are mapped
1512 * long page_size -- units for file_ofs
1513 * array of [COUNT] elements of
1514 *   long start
1515 *   long end
1516 *   long file_ofs
1517 * followed by COUNT filenames in ASCII: "FILE1" NUL "FILE2" NUL...
1518 */
1519static int fill_files_note(struct memelfnote *note)
1520{
1521	struct vm_area_struct *vma;
1522	unsigned count, size, names_ofs, remaining, n;
1523	user_long_t *data;
1524	user_long_t *start_end_ofs;
1525	char *name_base, *name_curpos;
 
1526
1527	/* *Estimated* file count and total data size needed */
1528	count = current->mm->map_count;
 
 
1529	size = count * 64;
1530
1531	names_ofs = (2 + 3 * count) * sizeof(data[0]);
1532 alloc:
1533	if (size >= MAX_FILE_NOTE_SIZE) /* paranoia check */
1534		return -EINVAL;
1535	size = round_up(size, PAGE_SIZE);
1536	data = vmalloc(size);
1537	if (!data)
 
 
 
 
1538		return -ENOMEM;
1539
1540	start_end_ofs = data + 2;
1541	name_base = name_curpos = ((char *)data) + names_ofs;
1542	remaining = size - names_ofs;
1543	count = 0;
1544	for (vma = current->mm->mmap; vma != NULL; vma = vma->vm_next) {
 
1545		struct file *file;
1546		const char *filename;
1547
1548		file = vma->vm_file;
1549		if (!file)
1550			continue;
1551		filename = file_path(file, name_curpos, remaining);
1552		if (IS_ERR(filename)) {
1553			if (PTR_ERR(filename) == -ENAMETOOLONG) {
1554				vfree(data);
1555				size = size * 5 / 4;
1556				goto alloc;
1557			}
1558			continue;
1559		}
1560
1561		/* file_path() fills at the end, move name down */
1562		/* n = strlen(filename) + 1: */
1563		n = (name_curpos + remaining) - filename;
1564		remaining = filename - name_curpos;
1565		memmove(name_curpos, filename, n);
1566		name_curpos += n;
1567
1568		*start_end_ofs++ = vma->vm_start;
1569		*start_end_ofs++ = vma->vm_end;
1570		*start_end_ofs++ = vma->vm_pgoff;
1571		count++;
1572	}
1573
1574	/* Now we know exact count of files, can store it */
1575	data[0] = count;
1576	data[1] = PAGE_SIZE;
1577	/*
1578	 * Count usually is less than current->mm->map_count,
1579	 * we need to move filenames down.
1580	 */
1581	n = current->mm->map_count - count;
1582	if (n != 0) {
1583		unsigned shift_bytes = n * 3 * sizeof(data[0]);
1584		memmove(name_base - shift_bytes, name_base,
1585			name_curpos - name_base);
1586		name_curpos -= shift_bytes;
1587	}
1588
1589	size = name_curpos - (char *)data;
1590	fill_note(note, "CORE", NT_FILE, size, data);
1591	return 0;
1592}
1593
1594#ifdef CORE_DUMP_USE_REGSET
1595#include <linux/regset.h>
1596
1597struct elf_thread_core_info {
1598	struct elf_thread_core_info *next;
1599	struct task_struct *task;
1600	struct elf_prstatus prstatus;
1601	struct memelfnote notes[0];
1602};
1603
1604struct elf_note_info {
1605	struct elf_thread_core_info *thread;
1606	struct memelfnote psinfo;
1607	struct memelfnote signote;
1608	struct memelfnote auxv;
1609	struct memelfnote files;
1610	user_siginfo_t csigdata;
1611	size_t size;
1612	int thread_notes;
1613};
1614
 
1615/*
1616 * When a regset has a writeback hook, we call it on each thread before
1617 * dumping user memory.  On register window machines, this makes sure the
1618 * user memory backing the register data is up to date before we read it.
1619 */
1620static void do_thread_regset_writeback(struct task_struct *task,
1621				       const struct user_regset *regset)
1622{
1623	if (regset->writeback)
1624		regset->writeback(task, regset, 1);
1625}
1626
1627#ifndef PRSTATUS_SIZE
1628#define PRSTATUS_SIZE(S, R) sizeof(S)
1629#endif
1630
1631#ifndef SET_PR_FPVALID
1632#define SET_PR_FPVALID(S, V, R) ((S)->pr_fpvalid = (V))
1633#endif
1634
1635static int fill_thread_core_info(struct elf_thread_core_info *t,
1636				 const struct user_regset_view *view,
1637				 long signr, size_t *total)
1638{
1639	unsigned int i;
1640	unsigned int regset_size = view->regsets[0].n * view->regsets[0].size;
1641
1642	/*
1643	 * NT_PRSTATUS is the one special case, because the regset data
1644	 * goes into the pr_reg field inside the note contents, rather
1645	 * than being the whole note contents.  We fill the reset in here.
1646	 * We assume that regset 0 is NT_PRSTATUS.
1647	 */
1648	fill_prstatus(&t->prstatus, t->task, signr);
1649	(void) view->regsets[0].get(t->task, &view->regsets[0], 0, regset_size,
1650				    &t->prstatus.pr_reg, NULL);
1651
1652	fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
1653		  PRSTATUS_SIZE(t->prstatus, regset_size), &t->prstatus);
1654	*total += notesize(&t->notes[0]);
1655
1656	do_thread_regset_writeback(t->task, &view->regsets[0]);
1657
1658	/*
1659	 * Each other regset might generate a note too.  For each regset
1660	 * that has no core_note_type or is inactive, we leave t->notes[i]
1661	 * all zero and we'll know to skip writing it later.
1662	 */
1663	for (i = 1; i < view->n; ++i) {
1664		const struct user_regset *regset = &view->regsets[i];
 
 
 
 
 
 
1665		do_thread_regset_writeback(t->task, regset);
1666		if (regset->core_note_type && regset->get &&
1667		    (!regset->active || regset->active(t->task, regset))) {
1668			int ret;
1669			size_t size = regset->n * regset->size;
1670			void *data = kmalloc(size, GFP_KERNEL);
1671			if (unlikely(!data))
1672				return 0;
1673			ret = regset->get(t->task, regset,
1674					  0, size, data, NULL);
1675			if (unlikely(ret))
1676				kfree(data);
1677			else {
1678				if (regset->core_note_type != NT_PRFPREG)
1679					fill_note(&t->notes[i], "LINUX",
1680						  regset->core_note_type,
1681						  size, data);
1682				else {
1683					SET_PR_FPVALID(&t->prstatus,
1684							1, regset_size);
1685					fill_note(&t->notes[i], "CORE",
1686						  NT_PRFPREG, size, data);
1687				}
1688				*total += notesize(&t->notes[i]);
1689			}
1690		}
1691	}
1692
1693	return 1;
1694}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1695
1696static int fill_note_info(struct elfhdr *elf, int phdrs,
1697			  struct elf_note_info *info,
1698			  const siginfo_t *siginfo, struct pt_regs *regs)
1699{
1700	struct task_struct *dump_task = current;
1701	const struct user_regset_view *view = task_user_regset_view(dump_task);
1702	struct elf_thread_core_info *t;
1703	struct elf_prpsinfo *psinfo;
1704	struct core_thread *ct;
1705	unsigned int i;
1706
1707	info->size = 0;
1708	info->thread = NULL;
1709
1710	psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
1711	if (psinfo == NULL) {
1712		info->psinfo.data = NULL; /* So we don't free this wrongly */
1713		return 0;
1714	}
1715
1716	fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
1717
 
 
 
1718	/*
1719	 * Figure out how many notes we're going to need for each thread.
1720	 */
1721	info->thread_notes = 0;
1722	for (i = 0; i < view->n; ++i)
1723		if (view->regsets[i].core_note_type != 0)
1724			++info->thread_notes;
1725
1726	/*
1727	 * Sanity check.  We rely on regset 0 being in NT_PRSTATUS,
1728	 * since it is our one special case.
1729	 */
1730	if (unlikely(info->thread_notes == 0) ||
1731	    unlikely(view->regsets[0].core_note_type != NT_PRSTATUS)) {
1732		WARN_ON(1);
1733		return 0;
1734	}
1735
1736	/*
1737	 * Initialize the ELF file header.
1738	 */
1739	fill_elf_header(elf, phdrs,
1740			view->e_machine, view->e_flags);
 
 
 
 
 
1741
1742	/*
1743	 * Allocate a structure for each thread.
1744	 */
1745	for (ct = &dump_task->mm->core_state->dumper; ct; ct = ct->next) {
 
 
 
 
 
 
 
1746		t = kzalloc(offsetof(struct elf_thread_core_info,
1747				     notes[info->thread_notes]),
1748			    GFP_KERNEL);
1749		if (unlikely(!t))
1750			return 0;
1751
1752		t->task = ct->task;
1753		if (ct->task == dump_task || !info->thread) {
1754			t->next = info->thread;
1755			info->thread = t;
1756		} else {
1757			/*
1758			 * Make sure to keep the original task at
1759			 * the head of the list.
1760			 */
1761			t->next = info->thread->next;
1762			info->thread->next = t;
1763		}
1764	}
1765
1766	/*
1767	 * Now fill in each thread's information.
1768	 */
1769	for (t = info->thread; t != NULL; t = t->next)
1770		if (!fill_thread_core_info(t, view, siginfo->si_signo, &info->size))
1771			return 0;
1772
1773	/*
1774	 * Fill in the two process-wide notes.
1775	 */
1776	fill_psinfo(psinfo, dump_task->group_leader, dump_task->mm);
1777	info->size += notesize(&info->psinfo);
1778
1779	fill_siginfo_note(&info->signote, &info->csigdata, siginfo);
1780	info->size += notesize(&info->signote);
1781
1782	fill_auxv_note(&info->auxv, current->mm);
1783	info->size += notesize(&info->auxv);
1784
1785	if (fill_files_note(&info->files) == 0)
1786		info->size += notesize(&info->files);
1787
1788	return 1;
1789}
1790
1791static size_t get_note_info_size(struct elf_note_info *info)
1792{
1793	return info->size;
1794}
1795
1796/*
1797 * Write all the notes for each thread.  When writing the first thread, the
1798 * process-wide notes are interleaved after the first thread-specific note.
1799 */
1800static int write_note_info(struct elf_note_info *info,
1801			   struct coredump_params *cprm)
1802{
1803	bool first = true;
1804	struct elf_thread_core_info *t = info->thread;
1805
1806	do {
1807		int i;
1808
1809		if (!writenote(&t->notes[0], cprm))
1810			return 0;
1811
1812		if (first && !writenote(&info->psinfo, cprm))
1813			return 0;
1814		if (first && !writenote(&info->signote, cprm))
1815			return 0;
1816		if (first && !writenote(&info->auxv, cprm))
1817			return 0;
1818		if (first && info->files.data &&
1819				!writenote(&info->files, cprm))
1820			return 0;
1821
1822		for (i = 1; i < info->thread_notes; ++i)
1823			if (t->notes[i].data &&
1824			    !writenote(&t->notes[i], cprm))
1825				return 0;
1826
1827		first = false;
1828		t = t->next;
1829	} while (t);
1830
1831	return 1;
1832}
1833
1834static void free_note_info(struct elf_note_info *info)
1835{
1836	struct elf_thread_core_info *threads = info->thread;
1837	while (threads) {
1838		unsigned int i;
1839		struct elf_thread_core_info *t = threads;
1840		threads = t->next;
1841		WARN_ON(t->notes[0].data && t->notes[0].data != &t->prstatus);
1842		for (i = 1; i < info->thread_notes; ++i)
1843			kfree(t->notes[i].data);
1844		kfree(t);
1845	}
1846	kfree(info->psinfo.data);
1847	vfree(info->files.data);
1848}
1849
1850#else
1851
1852/* Here is the structure in which status of each thread is captured. */
1853struct elf_thread_status
1854{
1855	struct list_head list;
1856	struct elf_prstatus prstatus;	/* NT_PRSTATUS */
1857	elf_fpregset_t fpu;		/* NT_PRFPREG */
1858	struct task_struct *thread;
1859#ifdef ELF_CORE_COPY_XFPREGS
1860	elf_fpxregset_t xfpu;		/* ELF_CORE_XFPREG_TYPE */
1861#endif
1862	struct memelfnote notes[3];
1863	int num_notes;
1864};
1865
1866/*
1867 * In order to add the specific thread information for the elf file format,
1868 * we need to keep a linked list of every threads pr_status and then create
1869 * a single section for them in the final core file.
1870 */
1871static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
1872{
1873	int sz = 0;
1874	struct task_struct *p = t->thread;
1875	t->num_notes = 0;
1876
1877	fill_prstatus(&t->prstatus, p, signr);
1878	elf_core_copy_task_regs(p, &t->prstatus.pr_reg);	
1879	
1880	fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
1881		  &(t->prstatus));
1882	t->num_notes++;
1883	sz += notesize(&t->notes[0]);
1884
1885	if ((t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL,
1886								&t->fpu))) {
1887		fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
1888			  &(t->fpu));
1889		t->num_notes++;
1890		sz += notesize(&t->notes[1]);
1891	}
1892
1893#ifdef ELF_CORE_COPY_XFPREGS
1894	if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
1895		fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
1896			  sizeof(t->xfpu), &t->xfpu);
1897		t->num_notes++;
1898		sz += notesize(&t->notes[2]);
1899	}
1900#endif	
1901	return sz;
1902}
1903
1904struct elf_note_info {
1905	struct memelfnote *notes;
1906	struct memelfnote *notes_files;
1907	struct elf_prstatus *prstatus;	/* NT_PRSTATUS */
1908	struct elf_prpsinfo *psinfo;	/* NT_PRPSINFO */
1909	struct list_head thread_list;
1910	elf_fpregset_t *fpu;
1911#ifdef ELF_CORE_COPY_XFPREGS
1912	elf_fpxregset_t *xfpu;
1913#endif
1914	user_siginfo_t csigdata;
1915	int thread_status_size;
1916	int numnote;
1917};
1918
1919static int elf_note_info_init(struct elf_note_info *info)
1920{
1921	memset(info, 0, sizeof(*info));
1922	INIT_LIST_HEAD(&info->thread_list);
1923
1924	/* Allocate space for ELF notes */
1925	info->notes = kmalloc(8 * sizeof(struct memelfnote), GFP_KERNEL);
1926	if (!info->notes)
1927		return 0;
1928	info->psinfo = kmalloc(sizeof(*info->psinfo), GFP_KERNEL);
1929	if (!info->psinfo)
1930		return 0;
1931	info->prstatus = kmalloc(sizeof(*info->prstatus), GFP_KERNEL);
1932	if (!info->prstatus)
1933		return 0;
1934	info->fpu = kmalloc(sizeof(*info->fpu), GFP_KERNEL);
1935	if (!info->fpu)
1936		return 0;
1937#ifdef ELF_CORE_COPY_XFPREGS
1938	info->xfpu = kmalloc(sizeof(*info->xfpu), GFP_KERNEL);
1939	if (!info->xfpu)
1940		return 0;
1941#endif
1942	return 1;
1943}
1944
1945static int fill_note_info(struct elfhdr *elf, int phdrs,
1946			  struct elf_note_info *info,
1947			  const siginfo_t *siginfo, struct pt_regs *regs)
1948{
1949	struct list_head *t;
1950	struct core_thread *ct;
1951	struct elf_thread_status *ets;
1952
1953	if (!elf_note_info_init(info))
1954		return 0;
1955
1956	for (ct = current->mm->core_state->dumper.next;
1957					ct; ct = ct->next) {
1958		ets = kzalloc(sizeof(*ets), GFP_KERNEL);
1959		if (!ets)
1960			return 0;
1961
1962		ets->thread = ct->task;
1963		list_add(&ets->list, &info->thread_list);
1964	}
1965
1966	list_for_each(t, &info->thread_list) {
1967		int sz;
1968
1969		ets = list_entry(t, struct elf_thread_status, list);
1970		sz = elf_dump_thread_status(siginfo->si_signo, ets);
1971		info->thread_status_size += sz;
1972	}
1973	/* now collect the dump for the current */
1974	memset(info->prstatus, 0, sizeof(*info->prstatus));
1975	fill_prstatus(info->prstatus, current, siginfo->si_signo);
1976	elf_core_copy_regs(&info->prstatus->pr_reg, regs);
1977
1978	/* Set up header */
1979	fill_elf_header(elf, phdrs, ELF_ARCH, ELF_CORE_EFLAGS);
1980
1981	/*
1982	 * Set up the notes in similar form to SVR4 core dumps made
1983	 * with info from their /proc.
1984	 */
1985
1986	fill_note(info->notes + 0, "CORE", NT_PRSTATUS,
1987		  sizeof(*info->prstatus), info->prstatus);
1988	fill_psinfo(info->psinfo, current->group_leader, current->mm);
1989	fill_note(info->notes + 1, "CORE", NT_PRPSINFO,
1990		  sizeof(*info->psinfo), info->psinfo);
1991
1992	fill_siginfo_note(info->notes + 2, &info->csigdata, siginfo);
1993	fill_auxv_note(info->notes + 3, current->mm);
1994	info->numnote = 4;
1995
1996	if (fill_files_note(info->notes + info->numnote) == 0) {
1997		info->notes_files = info->notes + info->numnote;
1998		info->numnote++;
1999	}
2000
2001	/* Try to dump the FPU. */
2002	info->prstatus->pr_fpvalid = elf_core_copy_task_fpregs(current, regs,
2003							       info->fpu);
2004	if (info->prstatus->pr_fpvalid)
2005		fill_note(info->notes + info->numnote++,
2006			  "CORE", NT_PRFPREG, sizeof(*info->fpu), info->fpu);
2007#ifdef ELF_CORE_COPY_XFPREGS
2008	if (elf_core_copy_task_xfpregs(current, info->xfpu))
2009		fill_note(info->notes + info->numnote++,
2010			  "LINUX", ELF_CORE_XFPREG_TYPE,
2011			  sizeof(*info->xfpu), info->xfpu);
2012#endif
2013
2014	return 1;
2015}
2016
2017static size_t get_note_info_size(struct elf_note_info *info)
2018{
2019	int sz = 0;
2020	int i;
2021
2022	for (i = 0; i < info->numnote; i++)
2023		sz += notesize(info->notes + i);
2024
2025	sz += info->thread_status_size;
2026
2027	return sz;
2028}
2029
2030static int write_note_info(struct elf_note_info *info,
2031			   struct coredump_params *cprm)
2032{
2033	int i;
2034	struct list_head *t;
2035
2036	for (i = 0; i < info->numnote; i++)
2037		if (!writenote(info->notes + i, cprm))
2038			return 0;
2039
2040	/* write out the thread status notes section */
2041	list_for_each(t, &info->thread_list) {
2042		struct elf_thread_status *tmp =
2043				list_entry(t, struct elf_thread_status, list);
2044
2045		for (i = 0; i < tmp->num_notes; i++)
2046			if (!writenote(&tmp->notes[i], cprm))
2047				return 0;
2048	}
2049
2050	return 1;
2051}
2052
2053static void free_note_info(struct elf_note_info *info)
2054{
2055	while (!list_empty(&info->thread_list)) {
2056		struct list_head *tmp = info->thread_list.next;
2057		list_del(tmp);
2058		kfree(list_entry(tmp, struct elf_thread_status, list));
2059	}
2060
2061	/* Free data possibly allocated by fill_files_note(): */
2062	if (info->notes_files)
2063		vfree(info->notes_files->data);
2064
2065	kfree(info->prstatus);
2066	kfree(info->psinfo);
2067	kfree(info->notes);
2068	kfree(info->fpu);
2069#ifdef ELF_CORE_COPY_XFPREGS
2070	kfree(info->xfpu);
2071#endif
2072}
2073
2074#endif
2075
2076static struct vm_area_struct *first_vma(struct task_struct *tsk,
2077					struct vm_area_struct *gate_vma)
2078{
2079	struct vm_area_struct *ret = tsk->mm->mmap;
2080
2081	if (ret)
2082		return ret;
2083	return gate_vma;
2084}
2085/*
2086 * Helper function for iterating across a vma list.  It ensures that the caller
2087 * will visit `gate_vma' prior to terminating the search.
2088 */
2089static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
2090					struct vm_area_struct *gate_vma)
2091{
2092	struct vm_area_struct *ret;
2093
2094	ret = this_vma->vm_next;
2095	if (ret)
2096		return ret;
2097	if (this_vma == gate_vma)
2098		return NULL;
2099	return gate_vma;
2100}
2101
2102static void fill_extnum_info(struct elfhdr *elf, struct elf_shdr *shdr4extnum,
2103			     elf_addr_t e_shoff, int segs)
2104{
2105	elf->e_shoff = e_shoff;
2106	elf->e_shentsize = sizeof(*shdr4extnum);
2107	elf->e_shnum = 1;
2108	elf->e_shstrndx = SHN_UNDEF;
2109
2110	memset(shdr4extnum, 0, sizeof(*shdr4extnum));
2111
2112	shdr4extnum->sh_type = SHT_NULL;
2113	shdr4extnum->sh_size = elf->e_shnum;
2114	shdr4extnum->sh_link = elf->e_shstrndx;
2115	shdr4extnum->sh_info = segs;
2116}
2117
2118/*
2119 * Actual dumper
2120 *
2121 * This is a two-pass process; first we find the offsets of the bits,
2122 * and then they are actually written out.  If we run out of core limit
2123 * we just truncate.
2124 */
2125static int elf_core_dump(struct coredump_params *cprm)
2126{
2127	int has_dumped = 0;
2128	mm_segment_t fs;
2129	int segs, i;
2130	size_t vma_data_size = 0;
2131	struct vm_area_struct *vma, *gate_vma;
2132	struct elfhdr *elf = NULL;
2133	loff_t offset = 0, dataoff;
2134	struct elf_note_info info = { };
2135	struct elf_phdr *phdr4note = NULL;
2136	struct elf_shdr *shdr4extnum = NULL;
2137	Elf_Half e_phnum;
2138	elf_addr_t e_shoff;
2139	elf_addr_t *vma_filesz = NULL;
2140
2141	/*
2142	 * We no longer stop all VM operations.
2143	 * 
2144	 * This is because those proceses that could possibly change map_count
2145	 * or the mmap / vma pages are now blocked in do_exit on current
2146	 * finishing this core dump.
2147	 *
2148	 * Only ptrace can touch these memory addresses, but it doesn't change
2149	 * the map_count or the pages allocated. So no possibility of crashing
2150	 * exists while dumping the mm->vm_next areas to the core file.
2151	 */
2152  
2153	/* alloc memory for large data structures: too large to be on stack */
2154	elf = kmalloc(sizeof(*elf), GFP_KERNEL);
2155	if (!elf)
2156		goto out;
2157	/*
2158	 * The number of segs are recored into ELF header as 16bit value.
2159	 * Please check DEFAULT_MAX_MAP_COUNT definition when you modify here.
2160	 */
2161	segs = current->mm->map_count;
2162	segs += elf_core_extra_phdrs();
2163
2164	gate_vma = get_gate_vma(current->mm);
2165	if (gate_vma != NULL)
2166		segs++;
2167
2168	/* for notes section */
2169	segs++;
2170
2171	/* If segs > PN_XNUM(0xffff), then e_phnum overflows. To avoid
2172	 * this, kernel supports extended numbering. Have a look at
2173	 * include/linux/elf.h for further information. */
2174	e_phnum = segs > PN_XNUM ? PN_XNUM : segs;
2175
2176	/*
2177	 * Collect all the non-memory information about the process for the
2178	 * notes.  This also sets up the file header.
2179	 */
2180	if (!fill_note_info(elf, e_phnum, &info, cprm->siginfo, cprm->regs))
2181		goto cleanup;
2182
2183	has_dumped = 1;
2184
2185	fs = get_fs();
2186	set_fs(KERNEL_DS);
2187
2188	offset += sizeof(*elf);				/* Elf header */
2189	offset += segs * sizeof(struct elf_phdr);	/* Program headers */
2190
2191	/* Write notes phdr entry */
2192	{
2193		size_t sz = get_note_info_size(&info);
2194
 
2195		sz += elf_coredump_extra_notes_size();
2196
2197		phdr4note = kmalloc(sizeof(*phdr4note), GFP_KERNEL);
2198		if (!phdr4note)
2199			goto end_coredump;
2200
2201		fill_elf_note_phdr(phdr4note, sz, offset);
2202		offset += sz;
2203	}
2204
2205	dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);
2206
2207	if (segs - 1 > ULONG_MAX / sizeof(*vma_filesz))
2208		goto end_coredump;
2209	vma_filesz = vmalloc((segs - 1) * sizeof(*vma_filesz));
2210	if (!vma_filesz)
2211		goto end_coredump;
2212
2213	for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
2214			vma = next_vma(vma, gate_vma)) {
2215		unsigned long dump_size;
2216
2217		dump_size = vma_dump_size(vma, cprm->mm_flags);
2218		vma_filesz[i++] = dump_size;
2219		vma_data_size += dump_size;
2220	}
2221
2222	offset += vma_data_size;
2223	offset += elf_core_extra_data_size();
2224	e_shoff = offset;
2225
2226	if (e_phnum == PN_XNUM) {
2227		shdr4extnum = kmalloc(sizeof(*shdr4extnum), GFP_KERNEL);
2228		if (!shdr4extnum)
2229			goto end_coredump;
2230		fill_extnum_info(elf, shdr4extnum, e_shoff, segs);
2231	}
2232
2233	offset = dataoff;
2234
2235	if (!dump_emit(cprm, elf, sizeof(*elf)))
2236		goto end_coredump;
2237
2238	if (!dump_emit(cprm, phdr4note, sizeof(*phdr4note)))
2239		goto end_coredump;
2240
2241	/* Write program headers for segments dump */
2242	for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
2243			vma = next_vma(vma, gate_vma)) {
2244		struct elf_phdr phdr;
2245
2246		phdr.p_type = PT_LOAD;
2247		phdr.p_offset = offset;
2248		phdr.p_vaddr = vma->vm_start;
2249		phdr.p_paddr = 0;
2250		phdr.p_filesz = vma_filesz[i++];
2251		phdr.p_memsz = vma->vm_end - vma->vm_start;
2252		offset += phdr.p_filesz;
2253		phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
2254		if (vma->vm_flags & VM_WRITE)
 
 
2255			phdr.p_flags |= PF_W;
2256		if (vma->vm_flags & VM_EXEC)
2257			phdr.p_flags |= PF_X;
2258		phdr.p_align = ELF_EXEC_PAGESIZE;
2259
2260		if (!dump_emit(cprm, &phdr, sizeof(phdr)))
2261			goto end_coredump;
2262	}
2263
2264	if (!elf_core_write_extra_phdrs(cprm, offset))
2265		goto end_coredump;
2266
2267 	/* write out the notes section */
2268	if (!write_note_info(&info, cprm))
2269		goto end_coredump;
2270
 
2271	if (elf_coredump_extra_notes_write(cprm))
2272		goto end_coredump;
2273
2274	/* Align to page */
2275	if (!dump_skip(cprm, dataoff - cprm->pos))
2276		goto end_coredump;
2277
2278	for (i = 0, vma = first_vma(current, gate_vma); vma != NULL;
2279			vma = next_vma(vma, gate_vma)) {
2280		unsigned long addr;
2281		unsigned long end;
2282
2283		end = vma->vm_start + vma_filesz[i++];
2284
2285		for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) {
2286			struct page *page;
2287			int stop;
2288
2289			page = get_dump_page(addr);
2290			if (page) {
2291				void *kaddr = kmap(page);
2292				stop = !dump_emit(cprm, kaddr, PAGE_SIZE);
2293				kunmap(page);
2294				put_page(page);
2295			} else
2296				stop = !dump_skip(cprm, PAGE_SIZE);
2297			if (stop)
2298				goto end_coredump;
2299		}
2300	}
2301	dump_truncate(cprm);
2302
2303	if (!elf_core_write_extra_data(cprm))
2304		goto end_coredump;
2305
2306	if (e_phnum == PN_XNUM) {
2307		if (!dump_emit(cprm, shdr4extnum, sizeof(*shdr4extnum)))
2308			goto end_coredump;
2309	}
2310
2311end_coredump:
2312	set_fs(fs);
2313
2314cleanup:
2315	free_note_info(&info);
2316	kfree(shdr4extnum);
2317	vfree(vma_filesz);
2318	kfree(phdr4note);
2319	kfree(elf);
2320out:
2321	return has_dumped;
2322}
2323
2324#endif		/* CONFIG_ELF_CORE */
2325
2326static int __init init_elf_binfmt(void)
2327{
2328	register_binfmt(&elf_format);
2329	return 0;
2330}
2331
2332static void __exit exit_elf_binfmt(void)
2333{
2334	/* Remove the COFF and ELF loaders. */
2335	unregister_binfmt(&elf_format);
2336}
2337
2338core_initcall(init_elf_binfmt);
2339module_exit(exit_elf_binfmt);
2340MODULE_LICENSE("GPL");