binfmt_elf.c 48.5 KB
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/*
 * linux/fs/binfmt_elf.c
 *
 * These are the functions used to load ELF format executables as used
 * on SVr4 machines.  Information on the format may be found in the book
 * "UNIX SYSTEM V RELEASE 4 Programmers Guide: Ansi C and Programming Support
 * Tools".
 *
 * Copyright 1993, 1994: Eric Youngdale (ericy@cais.com).
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/time.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/a.out.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/binfmts.h>
#include <linux/string.h>
#include <linux/file.h>
#include <linux/fcntl.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/shm.h>
#include <linux/personality.h>
#include <linux/elfcore.h>
#include <linux/init.h>
#include <linux/highuid.h>
#include <linux/smp.h>
#include <linux/compiler.h>
#include <linux/highmem.h>
#include <linux/pagemap.h>
#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/random.h>
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#include <linux/elf.h>
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#include <linux/utsname.h>
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#include <asm/uaccess.h>
#include <asm/param.h>
#include <asm/page.h>

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static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs);
static int load_elf_library(struct file *);
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static unsigned long elf_map (struct file *, unsigned long, struct elf_phdr *, int, int);
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/*
 * If we don't support core dumping, then supply a NULL so we
 * don't even try.
 */
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#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
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static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit);
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#else
#define elf_core_dump	NULL
#endif

#if ELF_EXEC_PAGESIZE > PAGE_SIZE
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#define ELF_MIN_ALIGN	ELF_EXEC_PAGESIZE
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#else
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#define ELF_MIN_ALIGN	PAGE_SIZE
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#endif

#ifndef ELF_CORE_EFLAGS
#define ELF_CORE_EFLAGS	0
#endif

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

static struct linux_binfmt elf_format = {
		.module		= THIS_MODULE,
		.load_binary	= load_elf_binary,
		.load_shlib	= load_elf_library,
		.core_dump	= elf_core_dump,
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		.min_coredump	= ELF_EXEC_PAGESIZE,
		.hasvdso	= 1
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};

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#define BAD_ADDR(x) ((unsigned long)(x) >= TASK_SIZE)
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static int set_brk(unsigned long start, unsigned long end)
{
	start = ELF_PAGEALIGN(start);
	end = ELF_PAGEALIGN(end);
	if (end > start) {
		unsigned long addr;
		down_write(&current->mm->mmap_sem);
		addr = do_brk(start, end - start);
		up_write(&current->mm->mmap_sem);
		if (BAD_ADDR(addr))
			return addr;
	}
	current->mm->start_brk = current->mm->brk = end;
	return 0;
}

/* We need to explicitly zero any fractional pages
   after the data section (i.e. bss).  This would
   contain the junk from the file that should not
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   be in memory
 */
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static int padzero(unsigned long elf_bss)
{
	unsigned long nbyte;

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

/* Let's use some macros to make this stack manipulation a litle clearer */
#ifdef CONFIG_STACK_GROWSUP
#define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) + (items))
#define STACK_ROUND(sp, items) \
	((15 + (unsigned long) ((sp) + (items))) &~ 15UL)
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#define STACK_ALLOC(sp, len) ({ \
	elf_addr_t __user *old_sp = (elf_addr_t __user *)sp; sp += len; \
	old_sp; })
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#else
#define STACK_ADD(sp, items) ((elf_addr_t __user *)(sp) - (items))
#define STACK_ROUND(sp, items) \
	(((unsigned long) (sp - items)) &~ 15UL)
#define STACK_ALLOC(sp, len) ({ sp -= len ; sp; })
#endif

static int
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create_elf_tables(struct linux_binprm *bprm, struct elfhdr *exec,
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		int interp_aout, unsigned long load_addr,
		unsigned long interp_load_addr)
{
	unsigned long p = bprm->p;
	int argc = bprm->argc;
	int envc = bprm->envc;
	elf_addr_t __user *argv;
	elf_addr_t __user *envp;
	elf_addr_t __user *sp;
	elf_addr_t __user *u_platform;
	const char *k_platform = ELF_PLATFORM;
	int items;
	elf_addr_t *elf_info;
	int ei_index = 0;
	struct task_struct *tsk = current;
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	struct vm_area_struct *vma;
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	/*
	 * In some cases (e.g. Hyper-Threading), we want to avoid L1
	 * evictions by the processes running on the same package. One
	 * thing we can do is to shuffle the initial stack for them.
	 */

	p = arch_align_stack(p);

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	/*
	 * If this architecture has a platform capability string, copy it
	 * to userspace.  In some cases (Sparc), this info is impossible
	 * for userspace to get any other way, in others (i386) it is
	 * merely difficult.
	 */
	u_platform = NULL;
	if (k_platform) {
		size_t len = strlen(k_platform) + 1;

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

	/* Create the ELF interpreter info */
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	elf_info = (elf_addr_t *)current->mm->saved_auxv;
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	/* update AT_VECTOR_SIZE_BASE if the number of NEW_AUX_ENT() changes */
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#define NEW_AUX_ENT(id, val) \
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	do { \
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		elf_info[ei_index++] = id; \
		elf_info[ei_index++] = val; \
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	} while (0)
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#ifdef ARCH_DLINFO
	/* 
	 * ARCH_DLINFO must come first so PPC can do its special alignment of
	 * AUXV.
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	 * update AT_VECTOR_SIZE_ARCH if the number of NEW_AUX_ENT() in
	 * ARCH_DLINFO changes
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	 */
	ARCH_DLINFO;
#endif
	NEW_AUX_ENT(AT_HWCAP, ELF_HWCAP);
	NEW_AUX_ENT(AT_PAGESZ, ELF_EXEC_PAGESIZE);
	NEW_AUX_ENT(AT_CLKTCK, CLOCKS_PER_SEC);
	NEW_AUX_ENT(AT_PHDR, load_addr + exec->e_phoff);
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	NEW_AUX_ENT(AT_PHENT, sizeof(struct elf_phdr));
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	NEW_AUX_ENT(AT_PHNUM, exec->e_phnum);
	NEW_AUX_ENT(AT_BASE, interp_load_addr);
	NEW_AUX_ENT(AT_FLAGS, 0);
	NEW_AUX_ENT(AT_ENTRY, exec->e_entry);
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	NEW_AUX_ENT(AT_UID, tsk->uid);
	NEW_AUX_ENT(AT_EUID, tsk->euid);
	NEW_AUX_ENT(AT_GID, tsk->gid);
	NEW_AUX_ENT(AT_EGID, tsk->egid);
 	NEW_AUX_ENT(AT_SECURE, security_bprm_secureexec(bprm));
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	if (k_platform) {
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		NEW_AUX_ENT(AT_PLATFORM,
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			    (elf_addr_t)(unsigned long)u_platform);
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	}
	if (bprm->interp_flags & BINPRM_FLAGS_EXECFD) {
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		NEW_AUX_ENT(AT_EXECFD, bprm->interp_data);
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	}
#undef NEW_AUX_ENT
	/* AT_NULL is zero; clear the rest too */
	memset(&elf_info[ei_index], 0,
	       sizeof current->mm->saved_auxv - ei_index * sizeof elf_info[0]);

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

	sp = STACK_ADD(p, ei_index);

	items = (argc + 1) + (envc + 1);
	if (interp_aout) {
		items += 3; /* a.out interpreters require argv & envp too */
	} else {
		items += 1; /* ELF interpreters only put argc on the stack */
	}
	bprm->p = STACK_ROUND(sp, items);

	/* Point sp at the lowest address on the stack */
#ifdef CONFIG_STACK_GROWSUP
	sp = (elf_addr_t __user *)bprm->p - items - ei_index;
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	bprm->exec = (unsigned long)sp; /* XXX: PARISC HACK */
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#else
	sp = (elf_addr_t __user *)bprm->p;
#endif

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

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	/* Now, let's put argc (and argv, envp if appropriate) on the stack */
	if (__put_user(argc, sp++))
		return -EFAULT;
	if (interp_aout) {
		argv = sp + 2;
		envp = argv + argc + 1;
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		if (__put_user((elf_addr_t)(unsigned long)argv, sp++) ||
		    __put_user((elf_addr_t)(unsigned long)envp, sp++))
			return -EFAULT;
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	} else {
		argv = sp;
		envp = argv + argc + 1;
	}

	/* Populate argv and envp */
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	p = current->mm->arg_end = current->mm->arg_start;
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	while (argc-- > 0) {
		size_t len;
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		if (__put_user((elf_addr_t)p, argv++))
			return -EFAULT;
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		len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
		if (!len || len > MAX_ARG_STRLEN)
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			return 0;
		p += len;
	}
	if (__put_user(0, argv))
		return -EFAULT;
	current->mm->arg_end = current->mm->env_start = p;
	while (envc-- > 0) {
		size_t len;
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		if (__put_user((elf_addr_t)p, envp++))
			return -EFAULT;
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		len = strnlen_user((void __user *)p, MAX_ARG_STRLEN);
		if (!len || len > MAX_ARG_STRLEN)
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			return 0;
		p += len;
	}
	if (__put_user(0, envp))
		return -EFAULT;
	current->mm->env_end = p;

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

#ifndef elf_map

static unsigned long elf_map(struct file *filep, unsigned long addr,
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		struct elf_phdr *eppnt, int prot, int type)
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{
	unsigned long map_addr;
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	unsigned long pageoffset = ELF_PAGEOFFSET(eppnt->p_vaddr);
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	down_write(&current->mm->mmap_sem);
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	/* mmap() will return -EINVAL if given a zero size, but a
	 * segment with zero filesize is perfectly valid */
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	if (eppnt->p_filesz + pageoffset)
		map_addr = do_mmap(filep, ELF_PAGESTART(addr),
				   eppnt->p_filesz + pageoffset, prot, type,
				   eppnt->p_offset - pageoffset);
	else
		map_addr = ELF_PAGESTART(addr);
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	up_write(&current->mm->mmap_sem);
	return(map_addr);
}

#endif /* !elf_map */

/* This is much more generalized than the library routine read function,
   so we keep this separate.  Technically the library read function
   is only provided so that we can read a.out libraries that have
   an ELF header */

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static unsigned long load_elf_interp(struct elfhdr *interp_elf_ex,
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		struct file *interpreter, unsigned long *interp_load_addr)
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{
	struct elf_phdr *elf_phdata;
	struct elf_phdr *eppnt;
	unsigned long load_addr = 0;
	int load_addr_set = 0;
	unsigned long last_bss = 0, elf_bss = 0;
	unsigned long error = ~0UL;
	int retval, i, size;

	/* First of all, some simple consistency checks */
	if (interp_elf_ex->e_type != ET_EXEC &&
	    interp_elf_ex->e_type != ET_DYN)
		goto out;
	if (!elf_check_arch(interp_elf_ex))
		goto out;
	if (!interpreter->f_op || !interpreter->f_op->mmap)
		goto out;

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

	/* Now read in all of the header information */
	size = sizeof(struct elf_phdr) * interp_elf_ex->e_phnum;
	if (size > ELF_MIN_ALIGN)
		goto out;
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	elf_phdata = kmalloc(size, GFP_KERNEL);
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	if (!elf_phdata)
		goto out;

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	retval = kernel_read(interpreter, interp_elf_ex->e_phoff,
			     (char *)elf_phdata,size);
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	error = -EIO;
	if (retval != size) {
		if (retval < 0)
			error = retval;	
		goto out_close;
	}

	eppnt = elf_phdata;
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	for (i = 0; i < interp_elf_ex->e_phnum; i++, eppnt++) {
		if (eppnt->p_type == PT_LOAD) {
			int elf_type = MAP_PRIVATE | MAP_DENYWRITE;
			int elf_prot = 0;
			unsigned long vaddr = 0;
			unsigned long k, map_addr;

			if (eppnt->p_flags & PF_R)
		    		elf_prot = PROT_READ;
			if (eppnt->p_flags & PF_W)
				elf_prot |= PROT_WRITE;
			if (eppnt->p_flags & PF_X)
				elf_prot |= PROT_EXEC;
			vaddr = eppnt->p_vaddr;
			if (interp_elf_ex->e_type == ET_EXEC || load_addr_set)
				elf_type |= MAP_FIXED;

			map_addr = elf_map(interpreter, load_addr + vaddr,
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					   eppnt, elf_prot, elf_type);
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			error = map_addr;
			if (BAD_ADDR(map_addr))
				goto out_close;

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

			/*
			 * Check to see if the section's size will overflow the
			 * allowed task size. Note that p_filesz must always be
			 * <= p_memsize so it's only necessary to check p_memsz.
			 */
			k = load_addr + eppnt->p_vaddr;
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			if (BAD_ADDR(k) ||
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			    eppnt->p_filesz > eppnt->p_memsz ||
			    eppnt->p_memsz > TASK_SIZE ||
			    TASK_SIZE - eppnt->p_memsz < k) {
				error = -ENOMEM;
				goto out_close;
			}

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

			/*
			 * Do the same thing for the memory mapping - between
			 * elf_bss and last_bss is the bss section.
			 */
			k = load_addr + eppnt->p_memsz + eppnt->p_vaddr;
			if (k > last_bss)
				last_bss = k;
		}
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	}

	/*
	 * Now fill out the bss section.  First pad the last page up
	 * to the page boundary, and then perform a mmap to make sure
	 * that there are zero-mapped pages up to and including the 
	 * last bss page.
	 */
	if (padzero(elf_bss)) {
		error = -EFAULT;
		goto out_close;
	}

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	/* What we have mapped so far */
	elf_bss = ELF_PAGESTART(elf_bss + ELF_MIN_ALIGN - 1);
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	/* Map the last of the bss segment */
	if (last_bss > elf_bss) {
		down_write(&current->mm->mmap_sem);
		error = do_brk(elf_bss, last_bss - elf_bss);
		up_write(&current->mm->mmap_sem);
		if (BAD_ADDR(error))
			goto out_close;
	}

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	*interp_load_addr = load_addr;
	error = ((unsigned long)interp_elf_ex->e_entry) + load_addr;
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out_close:
	kfree(elf_phdata);
out:
	return error;
}

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static unsigned long load_aout_interp(struct exec *interp_ex,
		struct file *interpreter)
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{
	unsigned long text_data, elf_entry = ~0UL;
	char __user * addr;
	loff_t offset;

	current->mm->end_code = interp_ex->a_text;
	text_data = interp_ex->a_text + interp_ex->a_data;
	current->mm->end_data = text_data;
	current->mm->brk = interp_ex->a_bss + text_data;

	switch (N_MAGIC(*interp_ex)) {
	case OMAGIC:
		offset = 32;
		addr = (char __user *)0;
		break;
	case ZMAGIC:
	case QMAGIC:
		offset = N_TXTOFF(*interp_ex);
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		addr = (char __user *)N_TXTADDR(*interp_ex);
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		break;
	default:
		goto out;
	}

	down_write(&current->mm->mmap_sem);	
	do_brk(0, text_data);
	up_write(&current->mm->mmap_sem);
	if (!interpreter->f_op || !interpreter->f_op->read)
		goto out;
	if (interpreter->f_op->read(interpreter, addr, text_data, &offset) < 0)
		goto out;
	flush_icache_range((unsigned long)addr,
	                   (unsigned long)addr + text_data);

	down_write(&current->mm->mmap_sem);	
	do_brk(ELF_PAGESTART(text_data + ELF_MIN_ALIGN - 1),
		interp_ex->a_bss);
	up_write(&current->mm->mmap_sem);
	elf_entry = interp_ex->a_entry;

out:
	return elf_entry;
}

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

#define INTERPRETER_NONE 0
#define INTERPRETER_AOUT 1
#define INTERPRETER_ELF 2

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#ifndef STACK_RND_MASK
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#define STACK_RND_MASK (0x7ff >> (PAGE_SHIFT - 12))	/* 8MB of VA */
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#endif
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static unsigned long randomize_stack_top(unsigned long stack_top)
{
	unsigned int random_variable = 0;

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	if ((current->flags & PF_RANDOMIZE) &&
		!(current->personality & ADDR_NO_RANDOMIZE)) {
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		random_variable = get_random_int() & STACK_RND_MASK;
		random_variable <<= PAGE_SHIFT;
	}
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#ifdef CONFIG_STACK_GROWSUP
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	return PAGE_ALIGN(stack_top) + random_variable;
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#else
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	return PAGE_ALIGN(stack_top) - random_variable;
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#endif
}

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static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs)
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{
	struct file *interpreter = NULL; /* to shut gcc up */
 	unsigned long load_addr = 0, load_bias = 0;
	int load_addr_set = 0;
	char * elf_interpreter = NULL;
	unsigned int interpreter_type = INTERPRETER_NONE;
	unsigned char ibcs2_interpreter = 0;
	unsigned long error;
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	struct elf_phdr *elf_ppnt, *elf_phdata;
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	unsigned long elf_bss, elf_brk;
	int elf_exec_fileno;
	int retval, i;
	unsigned int size;
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	unsigned long elf_entry, interp_load_addr = 0;
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	unsigned long start_code, end_code, start_data, end_data;
	unsigned long reloc_func_desc = 0;
	char passed_fileno[6];
	struct files_struct *files;
561
	int executable_stack = EXSTACK_DEFAULT;
L
Linus Torvalds 已提交
562 563 564 565 566 567 568 569 570 571 572 573 574 575
	unsigned long def_flags = 0;
	struct {
		struct elfhdr elf_ex;
		struct elfhdr interp_elf_ex;
  		struct exec interp_ex;
	} *loc;

	loc = kmalloc(sizeof(*loc), GFP_KERNEL);
	if (!loc) {
		retval = -ENOMEM;
		goto out_ret;
	}
	
	/* Get the exec-header */
576
	loc->elf_ex = *((struct elfhdr *)bprm->buf);
L
Linus Torvalds 已提交
577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597

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

	if (loc->elf_ex.e_type != ET_EXEC && loc->elf_ex.e_type != ET_DYN)
		goto out;
	if (!elf_check_arch(&loc->elf_ex))
		goto out;
	if (!bprm->file->f_op||!bprm->file->f_op->mmap)
		goto out;

	/* Now read in all of the header information */
	if (loc->elf_ex.e_phentsize != sizeof(struct elf_phdr))
		goto out;
	if (loc->elf_ex.e_phnum < 1 ||
	 	loc->elf_ex.e_phnum > 65536U / sizeof(struct elf_phdr))
		goto out;
	size = loc->elf_ex.e_phnum * sizeof(struct elf_phdr);
	retval = -ENOMEM;
598
	elf_phdata = kmalloc(size, GFP_KERNEL);
L
Linus Torvalds 已提交
599 600 601
	if (!elf_phdata)
		goto out;

602 603
	retval = kernel_read(bprm->file, loc->elf_ex.e_phoff,
			     (char *)elf_phdata, size);
L
Linus Torvalds 已提交
604 605 606 607 608 609
	if (retval != size) {
		if (retval >= 0)
			retval = -EIO;
		goto out_free_ph;
	}

610
	files = current->files;	/* Refcounted so ok */
L
Linus Torvalds 已提交
611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647
	retval = unshare_files();
	if (retval < 0)
		goto out_free_ph;
	if (files == current->files) {
		put_files_struct(files);
		files = NULL;
	}

	/* exec will make our files private anyway, but for the a.out
	   loader stuff we need to do it earlier */
	retval = get_unused_fd();
	if (retval < 0)
		goto out_free_fh;
	get_file(bprm->file);
	fd_install(elf_exec_fileno = retval, bprm->file);

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

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

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

			retval = -ENOMEM;
648
			elf_interpreter = kmalloc(elf_ppnt->p_filesz,
649
						  GFP_KERNEL);
L
Linus Torvalds 已提交
650 651 652 653
			if (!elf_interpreter)
				goto out_free_file;

			retval = kernel_read(bprm->file, elf_ppnt->p_offset,
654 655
					     elf_interpreter,
					     elf_ppnt->p_filesz);
L
Linus Torvalds 已提交
656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698
			if (retval != elf_ppnt->p_filesz) {
				if (retval >= 0)
					retval = -EIO;
				goto out_free_interp;
			}
			/* make sure path is NULL terminated */
			retval = -ENOEXEC;
			if (elf_interpreter[elf_ppnt->p_filesz - 1] != '\0')
				goto out_free_interp;

			/* If the program interpreter is one of these two,
			 * then assume an iBCS2 image. Otherwise assume
			 * a native linux image.
			 */
			if (strcmp(elf_interpreter,"/usr/lib/libc.so.1") == 0 ||
			    strcmp(elf_interpreter,"/usr/lib/ld.so.1") == 0)
				ibcs2_interpreter = 1;

			/*
			 * The early SET_PERSONALITY here is so that the lookup
			 * for the interpreter happens in the namespace of the 
			 * to-be-execed image.  SET_PERSONALITY can select an
			 * alternate root.
			 *
			 * However, SET_PERSONALITY is NOT allowed to switch
			 * this task into the new images's memory mapping
			 * policy - that is, TASK_SIZE must still evaluate to
			 * that which is appropriate to the execing application.
			 * This is because exit_mmap() needs to have TASK_SIZE
			 * evaluate to the size of the old image.
			 *
			 * So if (say) a 64-bit application is execing a 32-bit
			 * application it is the architecture's responsibility
			 * to defer changing the value of TASK_SIZE until the
			 * switch really is going to happen - do this in
			 * flush_thread().	- akpm
			 */
			SET_PERSONALITY(loc->elf_ex, ibcs2_interpreter);

			interpreter = open_exec(elf_interpreter);
			retval = PTR_ERR(interpreter);
			if (IS_ERR(interpreter))
				goto out_free_interp;
699 700 701 702 703 704 705 706 707

			/*
			 * If the binary is not readable then enforce
			 * mm->dumpable = 0 regardless of the interpreter's
			 * permissions.
			 */
			if (file_permission(interpreter, MAY_READ) < 0)
				bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;

708 709
			retval = kernel_read(interpreter, 0, bprm->buf,
					     BINPRM_BUF_SIZE);
L
Linus Torvalds 已提交
710 711 712 713 714 715 716
			if (retval != BINPRM_BUF_SIZE) {
				if (retval >= 0)
					retval = -EIO;
				goto out_free_dentry;
			}

			/* Get the exec headers */
717 718
			loc->interp_ex = *((struct exec *)bprm->buf);
			loc->interp_elf_ex = *((struct elfhdr *)bprm->buf);
L
Linus Torvalds 已提交
719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735
			break;
		}
		elf_ppnt++;
	}

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

	/* Some simple consistency checks for the interpreter */
	if (elf_interpreter) {
A
Andi Kleen 已提交
736
		static int warn;
L
Linus Torvalds 已提交
737 738 739 740 741 742 743 744 745 746 747
		interpreter_type = INTERPRETER_ELF | INTERPRETER_AOUT;

		/* Now figure out which format our binary is */
		if ((N_MAGIC(loc->interp_ex) != OMAGIC) &&
		    (N_MAGIC(loc->interp_ex) != ZMAGIC) &&
		    (N_MAGIC(loc->interp_ex) != QMAGIC))
			interpreter_type = INTERPRETER_ELF;

		if (memcmp(loc->interp_elf_ex.e_ident, ELFMAG, SELFMAG) != 0)
			interpreter_type &= ~INTERPRETER_ELF;

A
Andi Kleen 已提交
748 749 750 751 752 753 754
		if (interpreter_type == INTERPRETER_AOUT && warn < 10) {
			printk(KERN_WARNING "a.out ELF interpreter %s is "
				"deprecated and will not be supported "
				"after Linux 2.6.25\n", elf_interpreter);
			warn++;
		}

L
Linus Torvalds 已提交
755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809
		retval = -ELIBBAD;
		if (!interpreter_type)
			goto out_free_dentry;

		/* Make sure only one type was selected */
		if ((interpreter_type & INTERPRETER_ELF) &&
		     interpreter_type != INTERPRETER_ELF) {
	     		// FIXME - ratelimit this before re-enabling
			// printk(KERN_WARNING "ELF: Ambiguous type, using ELF\n");
			interpreter_type = INTERPRETER_ELF;
		}
		/* Verify the interpreter has a valid arch */
		if ((interpreter_type == INTERPRETER_ELF) &&
		    !elf_check_arch(&loc->interp_elf_ex))
			goto out_free_dentry;
	} else {
		/* Executables without an interpreter also need a personality  */
		SET_PERSONALITY(loc->elf_ex, ibcs2_interpreter);
	}

	/* OK, we are done with that, now set up the arg stuff,
	   and then start this sucker up */
	if ((!bprm->sh_bang) && (interpreter_type == INTERPRETER_AOUT)) {
		char *passed_p = passed_fileno;
		sprintf(passed_fileno, "%d", elf_exec_fileno);

		if (elf_interpreter) {
			retval = copy_strings_kernel(1, &passed_p, bprm);
			if (retval)
				goto out_free_dentry; 
			bprm->argc++;
		}
	}

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

	/* Discard our unneeded old files struct */
	if (files) {
		put_files_struct(files);
		files = NULL;
	}

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

	/* Do this immediately, since STACK_TOP as used in setup_arg_pages
	   may depend on the personality.  */
	SET_PERSONALITY(loc->elf_ex, ibcs2_interpreter);
	if (elf_read_implies_exec(loc->elf_ex, executable_stack))
		current->personality |= READ_IMPLIES_EXEC;

810
	if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
L
Linus Torvalds 已提交
811 812 813 814 815 816
		current->flags |= PF_RANDOMIZE;
	arch_pick_mmap_layout(current->mm);

	/* Do this so that we can load the interpreter, if need be.  We will
	   change some of these later */
	current->mm->free_area_cache = current->mm->mmap_base;
817
	current->mm->cached_hole_size = 0;
L
Linus Torvalds 已提交
818 819 820 821 822 823 824 825 826 827
	retval = setup_arg_pages(bprm, randomize_stack_top(STACK_TOP),
				 executable_stack);
	if (retval < 0) {
		send_sig(SIGKILL, current, 0);
		goto out_free_dentry;
	}
	
	current->mm->start_stack = bprm->p;

	/* Now we do a little grungy work by mmaping the ELF image into
A
Andrew Morton 已提交
828 829 830
	   the correct location in memory.  At this point, we assume that
	   the image should be loaded at fixed address, not at a variable
	   address. */
831 832
	for(i = 0, elf_ppnt = elf_phdata;
	    i < loc->elf_ex.e_phnum; i++, elf_ppnt++) {
L
Linus Torvalds 已提交
833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859
		int elf_prot = 0, elf_flags;
		unsigned long k, vaddr;

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

		if (unlikely (elf_brk > elf_bss)) {
			unsigned long nbyte;
	            
			/* There was a PT_LOAD segment with p_memsz > p_filesz
			   before this one. Map anonymous pages, if needed,
			   and clear the area.  */
			retval = set_brk (elf_bss + load_bias,
					  elf_brk + load_bias);
			if (retval) {
				send_sig(SIGKILL, current, 0);
				goto out_free_dentry;
			}
			nbyte = ELF_PAGEOFFSET(elf_bss);
			if (nbyte) {
				nbyte = ELF_MIN_ALIGN - nbyte;
				if (nbyte > elf_brk - elf_bss)
					nbyte = elf_brk - elf_bss;
				if (clear_user((void __user *)elf_bss +
							load_bias, nbyte)) {
					/*
					 * This bss-zeroing can fail if the ELF
860
					 * file specifies odd protections. So
L
Linus Torvalds 已提交
861 862 863 864 865 866
					 * we don't check the return value
					 */
				}
			}
		}

867 868 869 870 871 872
		if (elf_ppnt->p_flags & PF_R)
			elf_prot |= PROT_READ;
		if (elf_ppnt->p_flags & PF_W)
			elf_prot |= PROT_WRITE;
		if (elf_ppnt->p_flags & PF_X)
			elf_prot |= PROT_EXEC;
L
Linus Torvalds 已提交
873

874
		elf_flags = MAP_PRIVATE | MAP_DENYWRITE | MAP_EXECUTABLE;
L
Linus Torvalds 已提交
875 876 877 878 879

		vaddr = elf_ppnt->p_vaddr;
		if (loc->elf_ex.e_type == ET_EXEC || load_addr_set) {
			elf_flags |= MAP_FIXED;
		} else if (loc->elf_ex.e_type == ET_DYN) {
880 881 882 883
			/* Try and get dynamic programs out of the way of the
			 * default mmap base, as well as whatever program they
			 * might try to exec.  This is because the brk will
			 * follow the loader, and is not movable.  */
884
			load_bias = ELF_PAGESTART(ELF_ET_DYN_BASE - vaddr);
L
Linus Torvalds 已提交
885 886
		}

887
		error = elf_map(bprm->file, load_bias + vaddr, elf_ppnt,
A
Andrew Morton 已提交
888
				elf_prot, elf_flags);
L
Linus Torvalds 已提交
889 890
		if (BAD_ADDR(error)) {
			send_sig(SIGKILL, current, 0);
891 892
			retval = IS_ERR((void *)error) ?
				PTR_ERR((void*)error) : -EINVAL;
L
Linus Torvalds 已提交
893 894 895 896 897 898 899 900 901 902 903 904 905 906
			goto out_free_dentry;
		}

		if (!load_addr_set) {
			load_addr_set = 1;
			load_addr = (elf_ppnt->p_vaddr - elf_ppnt->p_offset);
			if (loc->elf_ex.e_type == ET_DYN) {
				load_bias += error -
				             ELF_PAGESTART(load_bias + vaddr);
				load_addr += load_bias;
				reloc_func_desc = load_bias;
			}
		}
		k = elf_ppnt->p_vaddr;
907 908 909 910
		if (k < start_code)
			start_code = k;
		if (start_data < k)
			start_data = k;
L
Linus Torvalds 已提交
911 912 913 914 915 916

		/*
		 * Check to see if the section's size will overflow the
		 * allowed task size. Note that p_filesz must always be
		 * <= p_memsz so it is only necessary to check p_memsz.
		 */
917
		if (BAD_ADDR(k) || elf_ppnt->p_filesz > elf_ppnt->p_memsz ||
L
Linus Torvalds 已提交
918 919
		    elf_ppnt->p_memsz > TASK_SIZE ||
		    TASK_SIZE - elf_ppnt->p_memsz < k) {
920
			/* set_brk can never work. Avoid overflows. */
L
Linus Torvalds 已提交
921
			send_sig(SIGKILL, current, 0);
922
			retval = -EINVAL;
L
Linus Torvalds 已提交
923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956
			goto out_free_dentry;
		}

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

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

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

	/* Calling set_brk effectively mmaps the pages that we need
	 * for the bss and break sections.  We must do this before
	 * mapping in the interpreter, to make sure it doesn't wind
	 * up getting placed where the bss needs to go.
	 */
	retval = set_brk(elf_bss, elf_brk);
	if (retval) {
		send_sig(SIGKILL, current, 0);
		goto out_free_dentry;
	}
A
akpm@osdl.org 已提交
957
	if (likely(elf_bss != elf_brk) && unlikely(padzero(elf_bss))) {
L
Linus Torvalds 已提交
958 959 960 961 962 963
		send_sig(SIGSEGV, current, 0);
		retval = -EFAULT; /* Nobody gets to see this, but.. */
		goto out_free_dentry;
	}

	if (elf_interpreter) {
A
Andrew Morton 已提交
964
		if (interpreter_type == INTERPRETER_AOUT)
L
Linus Torvalds 已提交
965 966
			elf_entry = load_aout_interp(&loc->interp_ex,
						     interpreter);
A
Andrew Morton 已提交
967
		else
L
Linus Torvalds 已提交
968 969
			elf_entry = load_elf_interp(&loc->interp_elf_ex,
						    interpreter,
A
Andrew Morton 已提交
970
						    &interp_load_addr);
L
Linus Torvalds 已提交
971 972
		if (BAD_ADDR(elf_entry)) {
			force_sig(SIGSEGV, current);
973 974
			retval = IS_ERR((void *)elf_entry) ?
					(int)elf_entry : -EINVAL;
L
Linus Torvalds 已提交
975 976 977 978 979 980 981 982 983
			goto out_free_dentry;
		}
		reloc_func_desc = interp_load_addr;

		allow_write_access(interpreter);
		fput(interpreter);
		kfree(elf_interpreter);
	} else {
		elf_entry = loc->elf_ex.e_entry;
984
		if (BAD_ADDR(elf_entry)) {
985 986
			force_sig(SIGSEGV, current);
			retval = -EINVAL;
987 988
			goto out_free_dentry;
		}
L
Linus Torvalds 已提交
989 990 991 992 993 994 995 996 997
	}

	kfree(elf_phdata);

	if (interpreter_type != INTERPRETER_AOUT)
		sys_close(elf_exec_fileno);

	set_binfmt(&elf_format);

998 999 1000 1001
#ifdef ARCH_HAS_SETUP_ADDITIONAL_PAGES
	retval = arch_setup_additional_pages(bprm, executable_stack);
	if (retval < 0) {
		send_sig(SIGKILL, current, 0);
1002
		goto out;
1003 1004 1005
	}
#endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */

L
Linus Torvalds 已提交
1006 1007
	compute_creds(bprm);
	current->flags &= ~PF_FORKNOEXEC;
1008
	retval = create_elf_tables(bprm, &loc->elf_ex,
1009 1010
			  (interpreter_type == INTERPRETER_AOUT),
			  load_addr, interp_load_addr);
1011 1012 1013 1014
	if (retval < 0) {
		send_sig(SIGKILL, current, 0);
		goto out;
	}
L
Linus Torvalds 已提交
1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027
	/* N.B. passed_fileno might not be initialized? */
	if (interpreter_type == INTERPRETER_AOUT)
		current->mm->arg_start += strlen(passed_fileno) + 1;
	current->mm->end_code = end_code;
	current->mm->start_code = start_code;
	current->mm->start_data = start_data;
	current->mm->end_data = end_data;
	current->mm->start_stack = bprm->p;

	if (current->personality & MMAP_PAGE_ZERO) {
		/* Why this, you ask???  Well SVr4 maps page 0 as read-only,
		   and some applications "depend" upon this behavior.
		   Since we do not have the power to recompile these, we
1028
		   emulate the SVr4 behavior. Sigh. */
L
Linus Torvalds 已提交
1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067
		down_write(&current->mm->mmap_sem);
		error = do_mmap(NULL, 0, PAGE_SIZE, PROT_READ | PROT_EXEC,
				MAP_FIXED | MAP_PRIVATE, 0);
		up_write(&current->mm->mmap_sem);
	}

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

	start_thread(regs, elf_entry, bprm->p);
	if (unlikely(current->ptrace & PT_PTRACED)) {
		if (current->ptrace & PT_TRACE_EXEC)
			ptrace_notify ((PTRACE_EVENT_EXEC << 8) | SIGTRAP);
		else
			send_sig(SIGTRAP, current, 0);
	}
	retval = 0;
out:
	kfree(loc);
out_ret:
	return retval;

	/* error cleanup */
out_free_dentry:
	allow_write_access(interpreter);
	if (interpreter)
		fput(interpreter);
out_free_interp:
J
Jesper Juhl 已提交
1068
	kfree(elf_interpreter);
L
Linus Torvalds 已提交
1069 1070 1071
out_free_file:
	sys_close(elf_exec_fileno);
out_free_fh:
1072 1073
	if (files)
		reset_files_struct(current, files);
L
Linus Torvalds 已提交
1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089
out_free_ph:
	kfree(elf_phdata);
	goto out;
}

/* This is really simpleminded and specialized - we are loading an
   a.out library that is given an ELF header. */
static int load_elf_library(struct file *file)
{
	struct elf_phdr *elf_phdata;
	struct elf_phdr *eppnt;
	unsigned long elf_bss, bss, len;
	int retval, error, i, j;
	struct elfhdr elf_ex;

	error = -ENOEXEC;
1090
	retval = kernel_read(file, 0, (char *)&elf_ex, sizeof(elf_ex));
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	if (retval != sizeof(elf_ex))
		goto out;

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

	/* First of all, some simple consistency checks */
	if (elf_ex.e_type != ET_EXEC || elf_ex.e_phnum > 2 ||
1099
	    !elf_check_arch(&elf_ex) || !file->f_op || !file->f_op->mmap)
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		goto out;

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

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

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

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

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

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

	/* Now use mmap to map the library into memory. */
	down_write(&current->mm->mmap_sem);
	error = do_mmap(file,
			ELF_PAGESTART(eppnt->p_vaddr),
			(eppnt->p_filesz +
			 ELF_PAGEOFFSET(eppnt->p_vaddr)),
			PROT_READ | PROT_WRITE | PROT_EXEC,
			MAP_FIXED | MAP_PRIVATE | MAP_DENYWRITE,
			(eppnt->p_offset -
			 ELF_PAGEOFFSET(eppnt->p_vaddr)));
	up_write(&current->mm->mmap_sem);
	if (error != ELF_PAGESTART(eppnt->p_vaddr))
		goto out_free_ph;

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

1147 1148
	len = ELF_PAGESTART(eppnt->p_filesz + eppnt->p_vaddr +
			    ELF_MIN_ALIGN - 1);
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	bss = eppnt->p_memsz + eppnt->p_vaddr;
	if (bss > len) {
		down_write(&current->mm->mmap_sem);
		do_brk(len, bss - len);
		up_write(&current->mm->mmap_sem);
	}
	error = 0;

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

/*
 * Note that some platforms still use traditional core dumps and not
 * the ELF core dump.  Each platform can select it as appropriate.
 */
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#if defined(USE_ELF_CORE_DUMP) && defined(CONFIG_ELF_CORE)
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/*
 * ELF core dumper
 *
 * Modelled on fs/exec.c:aout_core_dump()
 * Jeremy Fitzhardinge <jeremy@sw.oz.au>
 */
/*
 * These are the only things you should do on a core-file: use only these
 * functions to write out all the necessary info.
 */
static int dump_write(struct file *file, const void *addr, int nr)
{
	return file->f_op->write(file, addr, nr, &file->f_pos) == nr;
}

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static int dump_seek(struct file *file, loff_t off)
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{
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	if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
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		if (file->f_op->llseek(file, off, SEEK_CUR) < 0)
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			return 0;
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	} else {
		char *buf = (char *)get_zeroed_page(GFP_KERNEL);
		if (!buf)
			return 0;
		while (off > 0) {
			unsigned long n = off;
			if (n > PAGE_SIZE)
				n = PAGE_SIZE;
			if (!dump_write(file, buf, n))
				return 0;
			off -= n;
		}
		free_page((unsigned long)buf);
	}
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	return 1;
}

/*
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 * Decide what to dump of a segment, part, all or none.
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 */
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static unsigned long vma_dump_size(struct vm_area_struct *vma,
				   unsigned long mm_flags)
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{
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	/* The vma can be set up to tell us the answer directly.  */
	if (vma->vm_flags & VM_ALWAYSDUMP)
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		goto whole;
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	/* Do not dump I/O mapped devices or special mappings */
	if (vma->vm_flags & (VM_IO | VM_RESERVED))
		return 0;

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#define FILTER(type)	(mm_flags & (1UL << MMF_DUMP_##type))

1222 1223
	/* By default, dump shared memory if mapped from an anonymous file. */
	if (vma->vm_flags & VM_SHARED) {
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		if (vma->vm_file->f_path.dentry->d_inode->i_nlink == 0 ?
		    FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED))
			goto whole;
		return 0;
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	}
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	/* Dump segments that have been written to.  */
	if (vma->anon_vma && FILTER(ANON_PRIVATE))
		goto whole;
	if (vma->vm_file == NULL)
		return 0;
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	if (FILTER(MAPPED_PRIVATE))
		goto whole;

	/*
	 * If this looks like the beginning of a DSO or executable mapping,
	 * check for an ELF header.  If we find one, dump the first page to
	 * aid in determining what was mapped here.
	 */
	if (FILTER(ELF_HEADERS) && vma->vm_file != NULL && vma->vm_pgoff == 0) {
		u32 __user *header = (u32 __user *) vma->vm_start;
		u32 word;
		/*
		 * Doing it this way gets the constant folded by GCC.
		 */
		union {
			u32 cmp;
			char elfmag[SELFMAG];
		} magic;
		BUILD_BUG_ON(SELFMAG != sizeof word);
		magic.elfmag[EI_MAG0] = ELFMAG0;
		magic.elfmag[EI_MAG1] = ELFMAG1;
		magic.elfmag[EI_MAG2] = ELFMAG2;
		magic.elfmag[EI_MAG3] = ELFMAG3;
		if (get_user(word, header) == 0 && word == magic.cmp)
			return PAGE_SIZE;
	}

#undef	FILTER

	return 0;

whole:
	return vma->vm_end - vma->vm_start;
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}

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

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

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

	return sz;
}

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#define DUMP_WRITE(addr, nr, foffset)	\
	do { if (!dump_write(file, (addr), (nr))) return 0; *foffset += (nr); } while(0)
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static int alignfile(struct file *file, loff_t *foffset)
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{
1296
	static const char buf[4] = { 0, };
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	DUMP_WRITE(buf, roundup(*foffset, 4) - *foffset, foffset);
	return 1;
}
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static int writenote(struct memelfnote *men, struct file *file,
			loff_t *foffset)
{
	struct elf_note en;
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	en.n_namesz = strlen(men->name) + 1;
	en.n_descsz = men->datasz;
	en.n_type = men->type;

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	DUMP_WRITE(&en, sizeof(en), foffset);
	DUMP_WRITE(men->name, en.n_namesz, foffset);
	if (!alignfile(file, foffset))
		return 0;
	DUMP_WRITE(men->data, men->datasz, foffset);
	if (!alignfile(file, foffset))
		return 0;
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	return 1;
}
#undef DUMP_WRITE

#define DUMP_WRITE(addr, nr)	\
	if ((size += (nr)) > limit || !dump_write(file, (addr), (nr))) \
		goto end_coredump;
#define DUMP_SEEK(off)	\
	if (!dump_seek(file, (off))) \
		goto end_coredump;

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static void fill_elf_header(struct elfhdr *elf, int segs)
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{
	memcpy(elf->e_ident, ELFMAG, SELFMAG);
	elf->e_ident[EI_CLASS] = ELF_CLASS;
	elf->e_ident[EI_DATA] = ELF_DATA;
	elf->e_ident[EI_VERSION] = EV_CURRENT;
	elf->e_ident[EI_OSABI] = ELF_OSABI;
	memset(elf->e_ident+EI_PAD, 0, EI_NIDENT-EI_PAD);

	elf->e_type = ET_CORE;
	elf->e_machine = ELF_ARCH;
	elf->e_version = EV_CURRENT;
	elf->e_entry = 0;
	elf->e_phoff = sizeof(struct elfhdr);
	elf->e_shoff = 0;
	elf->e_flags = ELF_CORE_EFLAGS;
	elf->e_ehsize = sizeof(struct elfhdr);
	elf->e_phentsize = sizeof(struct elf_phdr);
	elf->e_phnum = segs;
	elf->e_shentsize = 0;
	elf->e_shnum = 0;
	elf->e_shstrndx = 0;
	return;
}

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static void fill_elf_note_phdr(struct elf_phdr *phdr, int sz, loff_t offset)
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{
	phdr->p_type = PT_NOTE;
	phdr->p_offset = offset;
	phdr->p_vaddr = 0;
	phdr->p_paddr = 0;
	phdr->p_filesz = sz;
	phdr->p_memsz = 0;
	phdr->p_flags = 0;
	phdr->p_align = 0;
	return;
}

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

/*
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 * fill up all the fields in prstatus from the given task struct, except
 * registers which need to be filled up separately.
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 */
static void fill_prstatus(struct elf_prstatus *prstatus,
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		struct task_struct *p, long signr)
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{
	prstatus->pr_info.si_signo = prstatus->pr_cursig = signr;
	prstatus->pr_sigpend = p->pending.signal.sig[0];
	prstatus->pr_sighold = p->blocked.sig[0];
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	prstatus->pr_pid = task_pid_vnr(p);
	prstatus->pr_ppid = task_pid_vnr(p->parent);
	prstatus->pr_pgrp = task_pgrp_vnr(p);
	prstatus->pr_sid = task_session_vnr(p);
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	if (thread_group_leader(p)) {
		/*
		 * This is the record for the group leader.  Add in the
		 * cumulative times of previous dead threads.  This total
		 * won't include the time of each live thread whose state
		 * is included in the core dump.  The final total reported
		 * to our parent process when it calls wait4 will include
		 * those sums as well as the little bit more time it takes
		 * this and each other thread to finish dying after the
		 * core dump synchronization phase.
		 */
		cputime_to_timeval(cputime_add(p->utime, p->signal->utime),
				   &prstatus->pr_utime);
		cputime_to_timeval(cputime_add(p->stime, p->signal->stime),
				   &prstatus->pr_stime);
	} else {
		cputime_to_timeval(p->utime, &prstatus->pr_utime);
		cputime_to_timeval(p->stime, &prstatus->pr_stime);
	}
	cputime_to_timeval(p->signal->cutime, &prstatus->pr_cutime);
	cputime_to_timeval(p->signal->cstime, &prstatus->pr_cstime);
}

static int fill_psinfo(struct elf_prpsinfo *psinfo, struct task_struct *p,
		       struct mm_struct *mm)
{
1416
	unsigned int i, len;
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	/* first copy the parameters from user space */
	memset(psinfo, 0, sizeof(struct elf_prpsinfo));

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

1432 1433 1434 1435
	psinfo->pr_pid = task_pid_vnr(p);
	psinfo->pr_ppid = task_pid_vnr(p->parent);
	psinfo->pr_pgrp = task_pgrp_vnr(p);
	psinfo->pr_sid = task_session_vnr(p);
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	i = p->state ? ffz(~p->state) + 1 : 0;
	psinfo->pr_state = i;
1439
	psinfo->pr_sname = (i > 5) ? '.' : "RSDTZW"[i];
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	psinfo->pr_zomb = psinfo->pr_sname == 'Z';
	psinfo->pr_nice = task_nice(p);
	psinfo->pr_flag = p->flags;
	SET_UID(psinfo->pr_uid, p->uid);
	SET_GID(psinfo->pr_gid, p->gid);
	strncpy(psinfo->pr_fname, p->comm, sizeof(psinfo->pr_fname));
	
	return 0;
}

/* Here is the structure in which status of each thread is captured. */
struct elf_thread_status
{
	struct list_head list;
	struct elf_prstatus prstatus;	/* NT_PRSTATUS */
	elf_fpregset_t fpu;		/* NT_PRFPREG */
	struct task_struct *thread;
#ifdef ELF_CORE_COPY_XFPREGS
1458
	elf_fpxregset_t xfpu;		/* ELF_CORE_XFPREG_TYPE */
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#endif
	struct memelfnote notes[3];
	int num_notes;
};

/*
 * In order to add the specific thread information for the elf file format,
1466 1467
 * we need to keep a linked list of every threads pr_status and then create
 * a single section for them in the final core file.
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 */
static int elf_dump_thread_status(long signr, struct elf_thread_status *t)
{
	int sz = 0;
	struct task_struct *p = t->thread;
	t->num_notes = 0;

	fill_prstatus(&t->prstatus, p, signr);
	elf_core_copy_task_regs(p, &t->prstatus.pr_reg);	
	
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	fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
		  &(t->prstatus));
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	t->num_notes++;
	sz += notesize(&t->notes[0]);

1483 1484 1485 1486
	if ((t->prstatus.pr_fpvalid = elf_core_copy_task_fpregs(p, NULL,
								&t->fpu))) {
		fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
			  &(t->fpu));
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		t->num_notes++;
		sz += notesize(&t->notes[1]);
	}

#ifdef ELF_CORE_COPY_XFPREGS
	if (elf_core_copy_task_xfpregs(p, &t->xfpu)) {
1493 1494
		fill_note(&t->notes[2], "LINUX", ELF_CORE_XFPREG_TYPE,
			  sizeof(t->xfpu), &t->xfpu);
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		t->num_notes++;
		sz += notesize(&t->notes[2]);
	}
#endif	
	return sz;
}

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static struct vm_area_struct *first_vma(struct task_struct *tsk,
					struct vm_area_struct *gate_vma)
{
	struct vm_area_struct *ret = tsk->mm->mmap;

	if (ret)
		return ret;
	return gate_vma;
}
/*
 * Helper function for iterating across a vma list.  It ensures that the caller
 * will visit `gate_vma' prior to terminating the search.
 */
static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma,
					struct vm_area_struct *gate_vma)
{
	struct vm_area_struct *ret;

	ret = this_vma->vm_next;
	if (ret)
		return ret;
	if (this_vma == gate_vma)
		return NULL;
	return gate_vma;
}

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/*
 * Actual dumper
 *
 * This is a two-pass process; first we find the offsets of the bits,
 * and then they are actually written out.  If we run out of core limit
 * we just truncate.
 */
1535
static int elf_core_dump(long signr, struct pt_regs *regs, struct file *file, unsigned long limit)
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{
#define	NUM_NOTES	6
	int has_dumped = 0;
	mm_segment_t fs;
	int segs;
	size_t size = 0;
	int i;
1543
	struct vm_area_struct *vma, *gate_vma;
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	struct elfhdr *elf = NULL;
1545
	loff_t offset = 0, dataoff, foffset;
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	int numnote;
	struct memelfnote *notes = NULL;
	struct elf_prstatus *prstatus = NULL;	/* NT_PRSTATUS */
	struct elf_prpsinfo *psinfo = NULL;	/* NT_PRPSINFO */
 	struct task_struct *g, *p;
 	LIST_HEAD(thread_list);
 	struct list_head *t;
	elf_fpregset_t *fpu = NULL;
#ifdef ELF_CORE_COPY_XFPREGS
	elf_fpxregset_t *xfpu = NULL;
#endif
	int thread_status_size = 0;
	elf_addr_t *auxv;
1559
	unsigned long mm_flags;
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	/*
	 * We no longer stop all VM operations.
	 * 
1564 1565 1566
	 * This is because those proceses that could possibly change map_count
	 * or the mmap / vma pages are now blocked in do_exit on current
	 * finishing this core dump.
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	 *
	 * Only ptrace can touch these memory addresses, but it doesn't change
1569
	 * the map_count or the pages allocated. So no possibility of crashing
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	 * exists while dumping the mm->vm_next areas to the core file.
	 */
  
	/* alloc memory for large data structures: too large to be on stack */
	elf = kmalloc(sizeof(*elf), GFP_KERNEL);
	if (!elf)
		goto cleanup;
	prstatus = kmalloc(sizeof(*prstatus), GFP_KERNEL);
	if (!prstatus)
		goto cleanup;
	psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
	if (!psinfo)
		goto cleanup;
	notes = kmalloc(NUM_NOTES * sizeof(struct memelfnote), GFP_KERNEL);
	if (!notes)
		goto cleanup;
	fpu = kmalloc(sizeof(*fpu), GFP_KERNEL);
	if (!fpu)
		goto cleanup;
#ifdef ELF_CORE_COPY_XFPREGS
	xfpu = kmalloc(sizeof(*xfpu), GFP_KERNEL);
	if (!xfpu)
		goto cleanup;
#endif

	if (signr) {
		struct elf_thread_status *tmp;
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		rcu_read_lock();
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		do_each_thread(g,p)
			if (current->mm == p->mm && current != p) {
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				tmp = kzalloc(sizeof(*tmp), GFP_ATOMIC);
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				if (!tmp) {
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					rcu_read_unlock();
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					goto cleanup;
				}
				tmp->thread = p;
				list_add(&tmp->list, &thread_list);
			}
		while_each_thread(g,p);
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		rcu_read_unlock();
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		list_for_each(t, &thread_list) {
			struct elf_thread_status *tmp;
			int sz;

			tmp = list_entry(t, struct elf_thread_status, list);
			sz = elf_dump_thread_status(signr, tmp);
			thread_status_size += sz;
		}
	}
	/* now collect the dump for the current */
	memset(prstatus, 0, sizeof(*prstatus));
	fill_prstatus(prstatus, current, signr);
	elf_core_copy_regs(&prstatus->pr_reg, regs);
	
	segs = current->mm->map_count;
#ifdef ELF_CORE_EXTRA_PHDRS
	segs += ELF_CORE_EXTRA_PHDRS;
#endif

1629 1630 1631 1632
	gate_vma = get_gate_vma(current);
	if (gate_vma != NULL)
		segs++;

L
Linus Torvalds 已提交
1633
	/* Set up header */
1634
	fill_elf_header(elf, segs + 1);	/* including notes section */
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Linus Torvalds 已提交
1635 1636 1637 1638 1639 1640 1641 1642 1643

	has_dumped = 1;
	current->flags |= PF_DUMPCORE;

	/*
	 * Set up the notes in similar form to SVR4 core dumps made
	 * with info from their /proc.
	 */

1644
	fill_note(notes + 0, "CORE", NT_PRSTATUS, sizeof(*prstatus), prstatus);
L
Linus Torvalds 已提交
1645
	fill_psinfo(psinfo, current->group_leader, current->mm);
1646
	fill_note(notes + 1, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
L
Linus Torvalds 已提交
1647
	
1648
	numnote = 2;
L
Linus Torvalds 已提交
1649

1650
	auxv = (elf_addr_t *)current->mm->saved_auxv;
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1651 1652 1653 1654 1655 1656

	i = 0;
	do
		i += 2;
	while (auxv[i - 2] != AT_NULL);
	fill_note(&notes[numnote++], "CORE", NT_AUXV,
1657
		  i * sizeof(elf_addr_t), auxv);
L
Linus Torvalds 已提交
1658 1659

  	/* Try to dump the FPU. */
1660 1661
	if ((prstatus->pr_fpvalid =
	     elf_core_copy_task_fpregs(current, regs, fpu)))
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Linus Torvalds 已提交
1662 1663 1664 1665 1666
		fill_note(notes + numnote++,
			  "CORE", NT_PRFPREG, sizeof(*fpu), fpu);
#ifdef ELF_CORE_COPY_XFPREGS
	if (elf_core_copy_task_xfpregs(current, xfpu))
		fill_note(notes + numnote++,
1667
			  "LINUX", ELF_CORE_XFPREG_TYPE, sizeof(*xfpu), xfpu);
L
Linus Torvalds 已提交
1668 1669 1670 1671 1672 1673 1674
#endif	
  
	fs = get_fs();
	set_fs(KERNEL_DS);

	DUMP_WRITE(elf, sizeof(*elf));
	offset += sizeof(*elf);				/* Elf header */
1675 1676
	offset += (segs + 1) * sizeof(struct elf_phdr); /* Program headers */
	foffset = offset;
L
Linus Torvalds 已提交
1677 1678 1679 1680 1681 1682 1683 1684 1685 1686 1687

	/* Write notes phdr entry */
	{
		struct elf_phdr phdr;
		int sz = 0;

		for (i = 0; i < numnote; i++)
			sz += notesize(notes + i);
		
		sz += thread_status_size;

1688
		sz += elf_coredump_extra_notes_size();
1689

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		fill_elf_note_phdr(&phdr, sz, offset);
		offset += sz;
		DUMP_WRITE(&phdr, sizeof(phdr));
	}

	dataoff = offset = roundup(offset, ELF_EXEC_PAGESIZE);

1697 1698 1699 1700 1701 1702 1703
	/*
	 * We must use the same mm->flags while dumping core to avoid
	 * inconsistency between the program headers and bodies, otherwise an
	 * unusable core file can be generated.
	 */
	mm_flags = current->mm->flags;

L
Linus Torvalds 已提交
1704
	/* Write program headers for segments dump */
1705 1706
	for (vma = first_vma(current, gate_vma); vma != NULL;
			vma = next_vma(vma, gate_vma)) {
L
Linus Torvalds 已提交
1707 1708 1709 1710 1711 1712
		struct elf_phdr phdr;

		phdr.p_type = PT_LOAD;
		phdr.p_offset = offset;
		phdr.p_vaddr = vma->vm_start;
		phdr.p_paddr = 0;
R
Roland McGrath 已提交
1713 1714
		phdr.p_filesz = vma_dump_size(vma, mm_flags);
		phdr.p_memsz = vma->vm_end - vma->vm_start;
L
Linus Torvalds 已提交
1715 1716
		offset += phdr.p_filesz;
		phdr.p_flags = vma->vm_flags & VM_READ ? PF_R : 0;
1717 1718 1719 1720
		if (vma->vm_flags & VM_WRITE)
			phdr.p_flags |= PF_W;
		if (vma->vm_flags & VM_EXEC)
			phdr.p_flags |= PF_X;
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1721 1722 1723 1724 1725 1726 1727 1728 1729 1730 1731
		phdr.p_align = ELF_EXEC_PAGESIZE;

		DUMP_WRITE(&phdr, sizeof(phdr));
	}

#ifdef ELF_CORE_WRITE_EXTRA_PHDRS
	ELF_CORE_WRITE_EXTRA_PHDRS;
#endif

 	/* write out the notes section */
	for (i = 0; i < numnote; i++)
1732
		if (!writenote(notes + i, file, &foffset))
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Linus Torvalds 已提交
1733 1734
			goto end_coredump;

1735 1736
	if (elf_coredump_extra_notes_write(file, &foffset))
		goto end_coredump;
1737

L
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1738 1739
	/* write out the thread status notes section */
	list_for_each(t, &thread_list) {
1740 1741 1742
		struct elf_thread_status *tmp =
				list_entry(t, struct elf_thread_status, list);

L
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1743
		for (i = 0; i < tmp->num_notes; i++)
1744
			if (!writenote(&tmp->notes[i], file, &foffset))
L
Linus Torvalds 已提交
1745 1746
				goto end_coredump;
	}
1747 1748 1749

	/* Align to page */
	DUMP_SEEK(dataoff - foffset);
L
Linus Torvalds 已提交
1750

1751 1752
	for (vma = first_vma(current, gate_vma); vma != NULL;
			vma = next_vma(vma, gate_vma)) {
L
Linus Torvalds 已提交
1753
		unsigned long addr;
R
Roland McGrath 已提交
1754
		unsigned long end;
L
Linus Torvalds 已提交
1755

R
Roland McGrath 已提交
1756
		end = vma->vm_start + vma_dump_size(vma, mm_flags);
L
Linus Torvalds 已提交
1757

R
Roland McGrath 已提交
1758
		for (addr = vma->vm_start; addr < end; addr += PAGE_SIZE) {
1759
			struct page *page;
L
Linus Torvalds 已提交
1760 1761 1762 1763
			struct vm_area_struct *vma;

			if (get_user_pages(current, current->mm, addr, 1, 0, 1,
						&page, &vma) <= 0) {
1764
				DUMP_SEEK(PAGE_SIZE);
L
Linus Torvalds 已提交
1765
			} else {
N
Nick Piggin 已提交
1766
				if (page == ZERO_PAGE(0)) {
1767 1768 1769 1770
					if (!dump_seek(file, PAGE_SIZE)) {
						page_cache_release(page);
						goto end_coredump;
					}
L
Linus Torvalds 已提交
1771 1772
				} else {
					void *kaddr;
1773 1774
					flush_cache_page(vma, addr,
							 page_to_pfn(page));
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1775 1776 1777 1778 1779 1780 1781 1782 1783 1784 1785 1786 1787 1788 1789 1790 1791 1792 1793 1794 1795 1796 1797
					kaddr = kmap(page);
					if ((size += PAGE_SIZE) > limit ||
					    !dump_write(file, kaddr,
					    PAGE_SIZE)) {
						kunmap(page);
						page_cache_release(page);
						goto end_coredump;
					}
					kunmap(page);
				}
				page_cache_release(page);
			}
		}
	}

#ifdef ELF_CORE_WRITE_EXTRA_DATA
	ELF_CORE_WRITE_EXTRA_DATA;
#endif

end_coredump:
	set_fs(fs);

cleanup:
1798
	while (!list_empty(&thread_list)) {
L
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1799 1800 1801 1802 1803 1804 1805 1806 1807 1808 1809 1810 1811 1812 1813 1814 1815 1816 1817 1818 1819 1820 1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831
		struct list_head *tmp = thread_list.next;
		list_del(tmp);
		kfree(list_entry(tmp, struct elf_thread_status, list));
	}

	kfree(elf);
	kfree(prstatus);
	kfree(psinfo);
	kfree(notes);
	kfree(fpu);
#ifdef ELF_CORE_COPY_XFPREGS
	kfree(xfpu);
#endif
	return has_dumped;
#undef NUM_NOTES
}

#endif		/* USE_ELF_CORE_DUMP */

static int __init init_elf_binfmt(void)
{
	return register_binfmt(&elf_format);
}

static void __exit exit_elf_binfmt(void)
{
	/* Remove the COFF and ELF loaders. */
	unregister_binfmt(&elf_format);
}

core_initcall(init_elf_binfmt);
module_exit(exit_elf_binfmt);
MODULE_LICENSE("GPL");