initial_commit

1 files changed, 2247 insertions, 0 deletions

diff --git a/fs/exec.c b/fs/exec.c
new file mode 100644
index 00000000..044c13ff
--- /dev/null
+++ b/fs/exec.c
@@ -0,0 +1,2247 @@
+/*
+ *  linux/fs/exec.c
+ *
+ *  Copyright (C) 1991, 1992  Linus Torvalds
+ */
+
+/*
+ * #!-checking implemented by tytso.
+ */
+/*
+ * Demand-loading implemented 01.12.91 - no need to read anything but
+ * the header into memory. The inode of the executable is put into
+ * "current->executable", and page faults do the actual loading. Clean.
+ *
+ * Once more I can proudly say that linux stood up to being changed: it
+ * was less than 2 hours work to get demand-loading completely implemented.
+ *
+ * Demand loading changed July 1993 by Eric Youngdale.   Use mmap instead,
+ * current->executable is only used by the procfs.  This allows a dispatch
+ * table to check for several different types  of binary formats.  We keep
+ * trying until we recognize the file or we run out of supported binary
+ * formats. 
+ */
+
+#include <linux/slab.h>
+#include <linux/file.h>
+#include <linux/fdtable.h>
+#include <linux/mm.h>
+#include <linux/stat.h>
+#include <linux/fcntl.h>
+#include <linux/swap.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/pagemap.h>
+#include <linux/perf_event.h>
+#include <linux/highmem.h>
+#include <linux/spinlock.h>
+#include <linux/key.h>
+#include <linux/personality.h>
+#include <linux/binfmts.h>
+#include <linux/utsname.h>
+#include <linux/pid_namespace.h>
+#include <linux/module.h>
+#include <linux/namei.h>
+#include <linux/mount.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/tsacct_kern.h>
+#include <linux/cn_proc.h>
+#include <linux/audit.h>
+#include <linux/tracehook.h>
+#include <linux/kmod.h>
+#include <linux/fsnotify.h>
+#include <linux/fs_struct.h>
+#include <linux/pipe_fs_i.h>
+#include <linux/oom.h>
+#include <linux/compat.h>
+
+#include <asm/uaccess.h>
+#include <asm/mmu_context.h>
+#include <asm/tlb.h>
+#include "internal.h"
+
+int core_uses_pid;
+char core_pattern[CORENAME_MAX_SIZE] = "core";
+unsigned int core_pipe_limit;
+int suid_dumpable = 0;
+
+struct core_name {
+	char *corename;
+	int used, size;
+};
+static atomic_t call_count = ATOMIC_INIT(1);
+
+/* The maximal length of core_pattern is also specified in sysctl.c */
+
+static LIST_HEAD(formats);
+static DEFINE_RWLOCK(binfmt_lock);
+
+int __register_binfmt(struct linux_binfmt * fmt, int insert)
+{
+	if (!fmt)
+		return -EINVAL;
+	write_lock(&binfmt_lock);
+	insert ? list_add(&fmt->lh, &formats) :
+		 list_add_tail(&fmt->lh, &formats);
+	write_unlock(&binfmt_lock);
+	return 0;	
+}
+
+EXPORT_SYMBOL(__register_binfmt);
+
+void unregister_binfmt(struct linux_binfmt * fmt)
+{
+	write_lock(&binfmt_lock);
+	list_del(&fmt->lh);
+	write_unlock(&binfmt_lock);
+}
+
+EXPORT_SYMBOL(unregister_binfmt);
+
+static inline void put_binfmt(struct linux_binfmt * fmt)
+{
+	module_put(fmt->module);
+}
+
+/*
+ * Note that a shared library must be both readable and executable due to
+ * security reasons.
+ *
+ * Also note that we take the address to load from from the file itself.
+ */
+SYSCALL_DEFINE1(uselib, const char __user *, library)
+{
+	struct file *file;
+	char *tmp = getname(library);
+	int error = PTR_ERR(tmp);
+	static const struct open_flags uselib_flags = {
+		.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
+		.acc_mode = MAY_READ | MAY_EXEC | MAY_OPEN,
+		.intent = LOOKUP_OPEN
+	};
+
+	if (IS_ERR(tmp))
+		goto out;
+
+	file = do_filp_open(AT_FDCWD, tmp, &uselib_flags, LOOKUP_FOLLOW);
+	putname(tmp);
+	error = PTR_ERR(file);
+	if (IS_ERR(file))
+		goto out;
+
+	error = -EINVAL;
+	if (!S_ISREG(file->f_path.dentry->d_inode->i_mode))
+		goto exit;
+
+	error = -EACCES;
+	if (file->f_path.mnt->mnt_flags & MNT_NOEXEC)
+		goto exit;
+
+	fsnotify_open(file);
+
+	error = -ENOEXEC;
+	if(file->f_op) {
+		struct linux_binfmt * fmt;
+
+		read_lock(&binfmt_lock);
+		list_for_each_entry(fmt, &formats, lh) {
+			if (!fmt->load_shlib)
+				continue;
+			if (!try_module_get(fmt->module))
+				continue;
+			read_unlock(&binfmt_lock);
+			error = fmt->load_shlib(file);
+			read_lock(&binfmt_lock);
+			put_binfmt(fmt);
+			if (error != -ENOEXEC)
+				break;
+		}
+		read_unlock(&binfmt_lock);
+	}
+exit:
+	fput(file);
+out:
+  	return error;
+}
+
+#ifdef CONFIG_MMU
+/*
+ * The nascent bprm->mm is not visible until exec_mmap() but it can
+ * use a lot of memory, account these pages in current->mm temporary
+ * for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we
+ * change the counter back via acct_arg_size(0).
+ */
+static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
+{
+	struct mm_struct *mm = current->mm;
+	long diff = (long)(pages - bprm->vma_pages);
+
+	if (!mm || !diff)
+		return;
+
+	bprm->vma_pages = pages;
+
+#ifdef SPLIT_RSS_COUNTING
+	add_mm_counter(mm, MM_ANONPAGES, diff);
+#else
+	spin_lock(&mm->page_table_lock);
+	add_mm_counter(mm, MM_ANONPAGES, diff);
+	spin_unlock(&mm->page_table_lock);
+#endif
+}
+
+static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
+		int write)
+{
+	struct page *page;
+	int ret;
+
+#ifdef CONFIG_STACK_GROWSUP
+	if (write) {
+		ret = expand_downwards(bprm->vma, pos);
+		if (ret < 0)
+			return NULL;
+	}
+#endif
+	ret = get_user_pages(current, bprm->mm, pos,
+			1, write, 1, &page, NULL);
+	if (ret <= 0)
+		return NULL;
+
+	if (write) {
+		unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
+		struct rlimit *rlim;
+
+		acct_arg_size(bprm, size / PAGE_SIZE);
+
+		/*
+		 * We've historically supported up to 32 pages (ARG_MAX)
+		 * of argument strings even with small stacks
+		 */
+		if (size <= ARG_MAX)
+			return page;
+
+		/*
+		 * Limit to 1/4-th the stack size for the argv+env strings.
+		 * This ensures that:
+		 *  - the remaining binfmt code will not run out of stack space,
+		 *  - the program will have a reasonable amount of stack left
+		 *    to work from.
+		 */
+		rlim = current->signal->rlim;
+		if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) {
+			put_page(page);
+			return NULL;
+		}
+	}
+
+	return page;
+}
+
+static void put_arg_page(struct page *page)
+{
+	put_page(page);
+}
+
+static void free_arg_page(struct linux_binprm *bprm, int i)
+{
+}
+
+static void free_arg_pages(struct linux_binprm *bprm)
+{
+}
+
+static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
+		struct page *page)
+{
+	flush_cache_page(bprm->vma, pos, page_to_pfn(page));
+}
+
+static int __bprm_mm_init(struct linux_binprm *bprm)
+{
+	int err;
+	struct vm_area_struct *vma = NULL;
+	struct mm_struct *mm = bprm->mm;
+
+	bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
+	if (!vma)
+		return -ENOMEM;
+
+	down_write(&mm->mmap_sem);
+	vma->vm_mm = mm;
+
+	/*
+	 * Place the stack at the largest stack address the architecture
+	 * supports. Later, we'll move this to an appropriate place. We don't
+	 * use STACK_TOP because that can depend on attributes which aren't
+	 * configured yet.
+	 */
+	BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP);
+	vma->vm_end = STACK_TOP_MAX;
+	vma->vm_start = vma->vm_end - PAGE_SIZE;
+	vma->vm_flags = VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP;
+	vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
+	INIT_LIST_HEAD(&vma->anon_vma_chain);
+
+	err = security_file_mmap(NULL, 0, 0, 0, vma->vm_start, 1);
+	if (err)
+		goto err;
+
+	err = insert_vm_struct(mm, vma);
+	if (err)
+		goto err;
+
+	mm->stack_vm = mm->total_vm = 1;
+	up_write(&mm->mmap_sem);
+	bprm->p = vma->vm_end - sizeof(void *);
+	return 0;
+err:
+	up_write(&mm->mmap_sem);
+	bprm->vma = NULL;
+	kmem_cache_free(vm_area_cachep, vma);
+	return err;
+}
+
+static bool valid_arg_len(struct linux_binprm *bprm, long len)
+{
+	return len <= MAX_ARG_STRLEN;
+}
+
+#else
+
+static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
+{
+}
+
+static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
+		int write)
+{
+	struct page *page;
+
+	page = bprm->page[pos / PAGE_SIZE];
+	if (!page && write) {
+		page = alloc_page(GFP_HIGHUSER|__GFP_ZERO);
+		if (!page)
+			return NULL;
+		bprm->page[pos / PAGE_SIZE] = page;
+	}
+
+	return page;
+}
+
+static void put_arg_page(struct page *page)
+{
+}
+
+static void free_arg_page(struct linux_binprm *bprm, int i)
+{
+	if (bprm->page[i]) {
+		__free_page(bprm->page[i]);
+		bprm->page[i] = NULL;
+	}
+}
+
+static void free_arg_pages(struct linux_binprm *bprm)
+{
+	int i;
+
+	for (i = 0; i < MAX_ARG_PAGES; i++)
+		free_arg_page(bprm, i);
+}
+
+static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
+		struct page *page)
+{
+}
+
+static int __bprm_mm_init(struct linux_binprm *bprm)
+{
+	bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *);
+	return 0;
+}
+
+static bool valid_arg_len(struct linux_binprm *bprm, long len)
+{
+	return len <= bprm->p;
+}
+
+#endif /* CONFIG_MMU */
+
+/*
+ * Create a new mm_struct and populate it with a temporary stack
+ * vm_area_struct.  We don't have enough context at this point to set the stack
+ * flags, permissions, and offset, so we use temporary values.  We'll update
+ * them later in setup_arg_pages().
+ */
+int bprm_mm_init(struct linux_binprm *bprm)
+{
+	int err;
+	struct mm_struct *mm = NULL;
+
+	bprm->mm = mm = mm_alloc();
+	err = -ENOMEM;
+	if (!mm)
+		goto err;
+
+	err = init_new_context(current, mm);
+	if (err)
+		goto err;
+
+	err = __bprm_mm_init(bprm);
+	if (err)
+		goto err;
+
+	return 0;
+
+err:
+	if (mm) {
+		bprm->mm = NULL;
+		mmdrop(mm);
+	}
+
+	return err;
+}
+
+struct user_arg_ptr {
+#ifdef CONFIG_COMPAT
+	bool is_compat;
+#endif
+	union {
+		const char __user *const __user *native;
+#ifdef CONFIG_COMPAT
+		compat_uptr_t __user *compat;
+#endif
+	} ptr;
+};
+
+static const char __user *get_user_arg_ptr(struct user_arg_ptr argv, int nr)
+{
+	const char __user *native;
+
+#ifdef CONFIG_COMPAT
+	if (unlikely(argv.is_compat)) {
+		compat_uptr_t compat;
+
+		if (get_user(compat, argv.ptr.compat + nr))
+			return ERR_PTR(-EFAULT);
+
+		return compat_ptr(compat);
+	}
+#endif
+
+	if (get_user(native, argv.ptr.native + nr))
+		return ERR_PTR(-EFAULT);
+
+	return native;
+}
+
+/*
+ * count() counts the number of strings in array ARGV.
+ */
+static int count(struct user_arg_ptr argv, int max)
+{
+	int i = 0;
+
+	if (argv.ptr.native != NULL) {
+		for (;;) {
+			const char __user *p = get_user_arg_ptr(argv, i);
+
+			if (!p)
+				break;
+
+			if (IS_ERR(p))
+				return -EFAULT;
+
+			if (i++ >= max)
+				return -E2BIG;
+
+			if (fatal_signal_pending(current))
+				return -ERESTARTNOHAND;
+			cond_resched();
+		}
+	}
+	return i;
+}
+
+/*
+ * 'copy_strings()' copies argument/environment strings from the old
+ * processes's memory to the new process's stack.  The call to get_user_pages()
+ * ensures the destination page is created and not swapped out.
+ */
+static int copy_strings(int argc, struct user_arg_ptr argv,
+			struct linux_binprm *bprm)
+{
+	struct page *kmapped_page = NULL;
+	char *kaddr = NULL;
+	unsigned long kpos = 0;
+	int ret;
+
+	while (argc-- > 0) {
+		const char __user *str;
+		int len;
+		unsigned long pos;
+
+		ret = -EFAULT;
+		str = get_user_arg_ptr(argv, argc);
+		if (IS_ERR(str))
+			goto out;
+
+		len = strnlen_user(str, MAX_ARG_STRLEN);
+		if (!len)
+			goto out;
+
+		ret = -E2BIG;
+		if (!valid_arg_len(bprm, len))
+			goto out;
+
+		/* We're going to work our way backwords. */
+		pos = bprm->p;
+		str += len;
+		bprm->p -= len;
+
+		while (len > 0) {
+			int offset, bytes_to_copy;
+
+			if (fatal_signal_pending(current)) {
+				ret = -ERESTARTNOHAND;
+				goto out;
+			}
+			cond_resched();
+
+			offset = pos % PAGE_SIZE;
+			if (offset == 0)
+				offset = PAGE_SIZE;
+
+			bytes_to_copy = offset;
+			if (bytes_to_copy > len)
+				bytes_to_copy = len;
+
+			offset -= bytes_to_copy;
+			pos -= bytes_to_copy;
+			str -= bytes_to_copy;
+			len -= bytes_to_copy;
+
+			if (!kmapped_page || kpos != (pos & PAGE_MASK)) {
+				struct page *page;
+
+				page = get_arg_page(bprm, pos, 1);
+				if (!page) {
+					ret = -E2BIG;
+					goto out;
+				}
+
+				if (kmapped_page) {
+					flush_kernel_dcache_page(kmapped_page);
+					kunmap(kmapped_page);
+					put_arg_page(kmapped_page);
+				}
+				kmapped_page = page;
+				kaddr = kmap(kmapped_page);
+				kpos = pos & PAGE_MASK;
+				flush_arg_page(bprm, kpos, kmapped_page);
+			}
+			if (copy_from_user(kaddr+offset, str, bytes_to_copy)) {
+				ret = -EFAULT;
+				goto out;
+			}
+		}
+	}
+	ret = 0;
+out:
+	if (kmapped_page) {
+		flush_kernel_dcache_page(kmapped_page);
+		kunmap(kmapped_page);
+		put_arg_page(kmapped_page);
+	}
+	return ret;
+}
+
+/*
+ * Like copy_strings, but get argv and its values from kernel memory.
+ */
+int copy_strings_kernel(int argc, const char *const *__argv,
+			struct linux_binprm *bprm)
+{
+	int r;
+	mm_segment_t oldfs = get_fs();
+	struct user_arg_ptr argv = {
+		.ptr.native = (const char __user *const  __user *)__argv,
+	};
+
+	set_fs(KERNEL_DS);
+	r = copy_strings(argc, argv, bprm);
+	set_fs(oldfs);
+
+	return r;
+}
+EXPORT_SYMBOL(copy_strings_kernel);
+
+#ifdef CONFIG_MMU
+
+/*
+ * During bprm_mm_init(), we create a temporary stack at STACK_TOP_MAX.  Once
+ * the binfmt code determines where the new stack should reside, we shift it to
+ * its final location.  The process proceeds as follows:
+ *
+ * 1) Use shift to calculate the new vma endpoints.
+ * 2) Extend vma to cover both the old and new ranges.  This ensures the
+ *    arguments passed to subsequent functions are consistent.
+ * 3) Move vma's page tables to the new range.
+ * 4) Free up any cleared pgd range.
+ * 5) Shrink the vma to cover only the new range.
+ */
+static int shift_arg_pages(struct vm_area_struct *vma, unsigned long shift)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	unsigned long old_start = vma->vm_start;
+	unsigned long old_end = vma->vm_end;
+	unsigned long length = old_end - old_start;
+	unsigned long new_start = old_start - shift;
+	unsigned long new_end = old_end - shift;
+	struct mmu_gather tlb;
+
+	BUG_ON(new_start > new_end);
+
+	/*
+	 * ensure there are no vmas between where we want to go
+	 * and where we are
+	 */
+	if (vma != find_vma(mm, new_start))
+		return -EFAULT;
+
+	/*
+	 * cover the whole range: [new_start, old_end)
+	 */
+	if (vma_adjust(vma, new_start, old_end, vma->vm_pgoff, NULL))
+		return -ENOMEM;
+
+	/*
+	 * move the page tables downwards, on failure we rely on
+	 * process cleanup to remove whatever mess we made.
+	 */
+	if (length != move_page_tables(vma, old_start,
+				       vma, new_start, length))
+		return -ENOMEM;
+
+	lru_add_drain();
+	tlb_gather_mmu(&tlb, mm, 0);
+	if (new_end > old_start) {
+		/*
+		 * when the old and new regions overlap clear from new_end.
+		 */
+		free_pgd_range(&tlb, new_end, old_end, new_end,
+			vma->vm_next ? vma->vm_next->vm_start : 0);
+	} else {
+		/*
+		 * otherwise, clean from old_start; this is done to not touch
+		 * the address space in [new_end, old_start) some architectures
+		 * have constraints on va-space that make this illegal (IA64) -
+		 * for the others its just a little faster.
+		 */
+		free_pgd_range(&tlb, old_start, old_end, new_end,
+			vma->vm_next ? vma->vm_next->vm_start : 0);
+	}
+	tlb_finish_mmu(&tlb, new_end, old_end);
+
+	/*
+	 * Shrink the vma to just the new range.  Always succeeds.
+	 */
+	vma_adjust(vma, new_start, new_end, vma->vm_pgoff, NULL);
+
+	return 0;
+}
+
+/*
+ * Finalizes the stack vm_area_struct. The flags and permissions are updated,
+ * the stack is optionally relocated, and some extra space is added.
+ */
+int setup_arg_pages(struct linux_binprm *bprm,
+		    unsigned long stack_top,
+		    int executable_stack)
+{
+	unsigned long ret;
+	unsigned long stack_shift;
+	struct mm_struct *mm = current->mm;
+	struct vm_area_struct *vma = bprm->vma;
+	struct vm_area_struct *prev = NULL;
+	unsigned long vm_flags;
+	unsigned long stack_base;
+	unsigned long stack_size;
+	unsigned long stack_expand;
+	unsigned long rlim_stack;
+
+#ifdef CONFIG_STACK_GROWSUP
+	/* Limit stack size to 1GB */
+	stack_base = rlimit_max(RLIMIT_STACK);
+	if (stack_base > (1 << 30))
+		stack_base = 1 << 30;
+
+	/* Make sure we didn't let the argument array grow too large. */
+	if (vma->vm_end - vma->vm_start > stack_base)
+		return -ENOMEM;
+
+	stack_base = PAGE_ALIGN(stack_top - stack_base);
+
+	stack_shift = vma->vm_start - stack_base;
+	mm->arg_start = bprm->p - stack_shift;
+	bprm->p = vma->vm_end - stack_shift;
+#else
+	stack_top = arch_align_stack(stack_top);
+	stack_top = PAGE_ALIGN(stack_top);
+
+	if (unlikely(stack_top < mmap_min_addr) ||
+	    unlikely(vma->vm_end - vma->vm_start >= stack_top - mmap_min_addr))
+		return -ENOMEM;
+
+	stack_shift = vma->vm_end - stack_top;
+
+	bprm->p -= stack_shift;
+	mm->arg_start = bprm->p;
+#endif
+
+	if (bprm->loader)
+		bprm->loader -= stack_shift;
+	bprm->exec -= stack_shift;
+
+	down_write(&mm->mmap_sem);
+	vm_flags = VM_STACK_FLAGS;
+
+	/*
+	 * Adjust stack execute permissions; explicitly enable for
+	 * EXSTACK_ENABLE_X, disable for EXSTACK_DISABLE_X and leave alone
+	 * (arch default) otherwise.
+	 */
+	if (unlikely(executable_stack == EXSTACK_ENABLE_X))
+		vm_flags |= VM_EXEC;
+	else if (executable_stack == EXSTACK_DISABLE_X)
+		vm_flags &= ~VM_EXEC;
+	vm_flags |= mm->def_flags;
+	vm_flags |= VM_STACK_INCOMPLETE_SETUP;
+
+	ret = mprotect_fixup(vma, &prev, vma->vm_start, vma->vm_end,
+			vm_flags);
+	if (ret)
+		goto out_unlock;
+	BUG_ON(prev != vma);
+
+	/* Move stack pages down in memory. */
+	if (stack_shift) {
+		ret = shift_arg_pages(vma, stack_shift);
+		if (ret)
+			goto out_unlock;
+	}
+
+	/* mprotect_fixup is overkill to remove the temporary stack flags */
+	vma->vm_flags &= ~VM_STACK_INCOMPLETE_SETUP;
+
+	stack_expand = 131072UL; /* randomly 32*4k (or 2*64k) pages */
+	stack_size = vma->vm_end - vma->vm_start;
+	/*
+	 * Align this down to a page boundary as expand_stack
+	 * will align it up.
+	 */
+	rlim_stack = rlimit(RLIMIT_STACK) & PAGE_MASK;
+#ifdef CONFIG_STACK_GROWSUP
+	if (stack_size + stack_expand > rlim_stack)
+		stack_base = vma->vm_start + rlim_stack;
+	else
+		stack_base = vma->vm_end + stack_expand;
+#else
+	if (stack_size + stack_expand > rlim_stack)
+		stack_base = vma->vm_end - rlim_stack;
+	else
+		stack_base = vma->vm_start - stack_expand;
+#endif
+	current->mm->start_stack = bprm->p;
+	ret = expand_stack(vma, stack_base);
+	if (ret)
+		ret = -EFAULT;
+
+out_unlock:
+	up_write(&mm->mmap_sem);
+	return ret;
+}
+EXPORT_SYMBOL(setup_arg_pages);
+
+#endif /* CONFIG_MMU */
+
+struct file *open_exec(const char *name)
+{
+	struct file *file;
+	int err;
+	static const struct open_flags open_exec_flags = {
+		.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
+		.acc_mode = MAY_EXEC | MAY_OPEN,
+		.intent = LOOKUP_OPEN
+	};
+
+	file = do_filp_open(AT_FDCWD, name, &open_exec_flags, LOOKUP_FOLLOW);
+	if (IS_ERR(file))
+		goto out;
+
+	err = -EACCES;
+	if (!S_ISREG(file->f_path.dentry->d_inode->i_mode))
+		goto exit;
+
+	if (file->f_path.mnt->mnt_flags & MNT_NOEXEC)
+		goto exit;
+
+	fsnotify_open(file);
+
+	err = deny_write_access(file);
+	if (err)
+		goto exit;
+
+out:
+	return file;
+
+exit:
+	fput(file);
+	return ERR_PTR(err);
+}
+EXPORT_SYMBOL(open_exec);
+
+int kernel_read(struct file *file, loff_t offset,
+		char *addr, unsigned long count)
+{
+	mm_segment_t old_fs;
+	loff_t pos = offset;
+	int result;
+
+	old_fs = get_fs();
+	set_fs(get_ds());
+	/* The cast to a user pointer is valid due to the set_fs() */
+	result = vfs_read(file, (void __user *)addr, count, &pos);
+	set_fs(old_fs);
+	return result;
+}
+
+EXPORT_SYMBOL(kernel_read);
+
+static int exec_mmap(struct mm_struct *mm)
+{
+	struct task_struct *tsk;
+	struct mm_struct * old_mm, *active_mm;
+
+	/* Notify parent that we're no longer interested in the old VM */
+	tsk = current;
+	old_mm = current->mm;
+	sync_mm_rss(tsk, old_mm);
+	mm_release(tsk, old_mm);
+
+	if (old_mm) {
+		/*
+		 * Make sure that if there is a core dump in progress
+		 * for the old mm, we get out and die instead of going
+		 * through with the exec.  We must hold mmap_sem around
+		 * checking core_state and changing tsk->mm.
+		 */
+		down_read(&old_mm->mmap_sem);
+		if (unlikely(old_mm->core_state)) {
+			up_read(&old_mm->mmap_sem);
+			return -EINTR;
+		}
+	}
+	task_lock(tsk);
+	active_mm = tsk->active_mm;
+	tsk->mm = mm;
+	tsk->active_mm = mm;
+	activate_mm(active_mm, mm);
+	if (old_mm && tsk->signal->oom_score_adj == OOM_SCORE_ADJ_MIN) {
+		atomic_dec(&old_mm->oom_disable_count);
+		atomic_inc(&tsk->mm->oom_disable_count);
+	}
+	task_unlock(tsk);
+	arch_pick_mmap_layout(mm);
+	if (old_mm) {
+		up_read(&old_mm->mmap_sem);
+		BUG_ON(active_mm != old_mm);
+		mm_update_next_owner(old_mm);
+		mmput(old_mm);
+		return 0;
+	}
+	mmdrop(active_mm);
+	return 0;
+}
+
+/*
+ * This function makes sure the current process has its own signal table,
+ * so that flush_signal_handlers can later reset the handlers without
+ * disturbing other processes.  (Other processes might share the signal
+ * table via the CLONE_SIGHAND option to clone().)
+ */
+static int de_thread(struct task_struct *tsk)
+{
+	struct signal_struct *sig = tsk->signal;
+	struct sighand_struct *oldsighand = tsk->sighand;
+	spinlock_t *lock = &oldsighand->siglock;
+
+	if (thread_group_empty(tsk))
+		goto no_thread_group;
+
+	/*
+	 * Kill all other threads in the thread group.
+	 */
+	spin_lock_irq(lock);
+	if (signal_group_exit(sig)) {
+		/*
+		 * Another group action in progress, just
+		 * return so that the signal is processed.
+		 */
+		spin_unlock_irq(lock);
+		return -EAGAIN;
+	}
+
+	sig->group_exit_task = tsk;
+	sig->notify_count = zap_other_threads(tsk);
+	if (!thread_group_leader(tsk))
+		sig->notify_count--;
+
+	while (sig->notify_count) {
+		__set_current_state(TASK_UNINTERRUPTIBLE);
+		spin_unlock_irq(lock);
+		schedule();
+		spin_lock_irq(lock);
+	}
+	spin_unlock_irq(lock);
+
+	/*
+	 * At this point all other threads have exited, all we have to
+	 * do is to wait for the thread group leader to become inactive,
+	 * and to assume its PID:
+	 */
+	if (!thread_group_leader(tsk)) {
+		struct task_struct *leader = tsk->group_leader;
+
+		sig->notify_count = -1;	/* for exit_notify() */
+		for (;;) {
+			write_lock_irq(&tasklist_lock);
+			if (likely(leader->exit_state))
+				break;
+			__set_current_state(TASK_UNINTERRUPTIBLE);
+			write_unlock_irq(&tasklist_lock);
+			schedule();
+		}
+
+		/*
+		 * The only record we have of the real-time age of a
+		 * process, regardless of execs it's done, is start_time.
+		 * All the past CPU time is accumulated in signal_struct
+		 * from sister threads now dead.  But in this non-leader
+		 * exec, nothing survives from the original leader thread,
+		 * whose birth marks the true age of this process now.
+		 * When we take on its identity by switching to its PID, we
+		 * also take its birthdate (always earlier than our own).
+		 */
+		tsk->start_time = leader->start_time;
+
+		BUG_ON(!same_thread_group(leader, tsk));
+		BUG_ON(has_group_leader_pid(tsk));
+		/*
+		 * An exec() starts a new thread group with the
+		 * TGID of the previous thread group. Rehash the
+		 * two threads with a switched PID, and release
+		 * the former thread group leader:
+		 */
+
+		/* Become a process group leader with the old leader's pid.
+		 * The old leader becomes a thread of the this thread group.
+		 * Note: The old leader also uses this pid until release_task
+		 *       is called.  Odd but simple and correct.
+		 */
+		detach_pid(tsk, PIDTYPE_PID);
+		tsk->pid = leader->pid;
+		attach_pid(tsk, PIDTYPE_PID,  task_pid(leader));
+		transfer_pid(leader, tsk, PIDTYPE_PGID);
+		transfer_pid(leader, tsk, PIDTYPE_SID);
+
+		list_replace_rcu(&leader->tasks, &tsk->tasks);
+		list_replace_init(&leader->sibling, &tsk->sibling);
+
+		tsk->group_leader = tsk;
+		leader->group_leader = tsk;
+
+		tsk->exit_signal = SIGCHLD;
+
+		BUG_ON(leader->exit_state != EXIT_ZOMBIE);
+		leader->exit_state = EXIT_DEAD;
+		write_unlock_irq(&tasklist_lock);
+
+		release_task(leader);
+	}
+
+	sig->group_exit_task = NULL;
+	sig->notify_count = 0;
+
+no_thread_group:
+	if (current->mm)
+		setmax_mm_hiwater_rss(&sig->maxrss, current->mm);
+
+	exit_itimers(sig);
+	flush_itimer_signals();
+
+	if (atomic_read(&oldsighand->count) != 1) {
+		struct sighand_struct *newsighand;
+		/*
+		 * This ->sighand is shared with the CLONE_SIGHAND
+		 * but not CLONE_THREAD task, switch to the new one.
+		 */
+		newsighand = kmem_cache_alloc(sighand_cachep, GFP_KERNEL);
+		if (!newsighand)
+			return -ENOMEM;
+
+		atomic_set(&newsighand->count, 1);
+		memcpy(newsighand->action, oldsighand->action,
+		       sizeof(newsighand->action));
+
+		write_lock_irq(&tasklist_lock);
+		spin_lock(&oldsighand->siglock);
+		rcu_assign_pointer(tsk->sighand, newsighand);
+		spin_unlock(&oldsighand->siglock);
+		write_unlock_irq(&tasklist_lock);
+
+		__cleanup_sighand(oldsighand);
+	}
+
+	BUG_ON(!thread_group_leader(tsk));
+	return 0;
+}
+
+/*
+ * These functions flushes out all traces of the currently running executable
+ * so that a new one can be started
+ */
+static void flush_old_files(struct files_struct * files)
+{
+	long j = -1;
+	struct fdtable *fdt;
+
+	spin_lock(&files->file_lock);
+	for (;;) {
+		unsigned long set, i;
+
+		j++;
+		i = j * __NFDBITS;
+		fdt = files_fdtable(files);
+		if (i >= fdt->max_fds)
+			break;
+		set = fdt->close_on_exec->fds_bits[j];
+		if (!set)
+			continue;
+		fdt->close_on_exec->fds_bits[j] = 0;
+		spin_unlock(&files->file_lock);
+		for ( ; set ; i++,set >>= 1) {
+			if (set & 1) {
+				sys_close(i);
+			}
+		}
+		spin_lock(&files->file_lock);
+
+	}
+	spin_unlock(&files->file_lock);
+}
+
+char *get_task_comm(char *buf, struct task_struct *tsk)
+{
+	/* buf must be at least sizeof(tsk->comm) in size */
+	task_lock(tsk);
+	strncpy(buf, tsk->comm, sizeof(tsk->comm));
+	task_unlock(tsk);
+	return buf;
+}
+EXPORT_SYMBOL_GPL(get_task_comm);
+
+void set_task_comm(struct task_struct *tsk, char *buf)
+{
+	task_lock(tsk);
+
+	/*
+	 * Threads may access current->comm without holding
+	 * the task lock, so write the string carefully.
+	 * Readers without a lock may see incomplete new
+	 * names but are safe from non-terminating string reads.
+	 */
+	memset(tsk->comm, 0, TASK_COMM_LEN);
+	wmb();
+	strlcpy(tsk->comm, buf, sizeof(tsk->comm));
+	task_unlock(tsk);
+	perf_event_comm(tsk);
+}
+
+int flush_old_exec(struct linux_binprm * bprm)
+{
+	int retval;
+
+	/*
+	 * Make sure we have a private signal table and that
+	 * we are unassociated from the previous thread group.
+	 */
+	retval = de_thread(current);
+	if (retval)
+		goto out;
+
+	set_mm_exe_file(bprm->mm, bprm->file);
+
+	/*
+	 * Release all of the old mmap stuff
+	 */
+	acct_arg_size(bprm, 0);
+	retval = exec_mmap(bprm->mm);
+	if (retval)
+		goto out;
+
+	bprm->mm = NULL;		/* We're using it now */
+
+	set_fs(USER_DS);
+	current->flags &= ~(PF_RANDOMIZE | PF_KTHREAD);
+	flush_thread();
+	current->personality &= ~bprm->per_clear;
+
+	return 0;
+
+out:
+	return retval;
+}
+EXPORT_SYMBOL(flush_old_exec);
+
+void setup_new_exec(struct linux_binprm * bprm)
+{
+	int i, ch;
+	const char *name;
+	char tcomm[sizeof(current->comm)];
+
+	arch_pick_mmap_layout(current->mm);
+
+	/* This is the point of no return */
+	current->sas_ss_sp = current->sas_ss_size = 0;
+
+	if (current_euid() == current_uid() && current_egid() == current_gid())
+		set_dumpable(current->mm, 1);
+	else
+		set_dumpable(current->mm, suid_dumpable);
+
+	name = bprm->filename;
+
+	/* Copies the binary name from after last slash */
+	for (i=0; (ch = *(name++)) != '\0';) {
+		if (ch == '/')
+			i = 0; /* overwrite what we wrote */
+		else
+			if (i < (sizeof(tcomm) - 1))
+				tcomm[i++] = ch;
+	}
+	tcomm[i] = '\0';
+	set_task_comm(current, tcomm);
+
+	/* Set the new mm task size. We have to do that late because it may
+	 * depend on TIF_32BIT which is only updated in flush_thread() on
+	 * some architectures like powerpc
+	 */
+	current->mm->task_size = TASK_SIZE;
+
+	/* install the new credentials */
+	if (bprm->cred->uid != current_euid() ||
+	    bprm->cred->gid != current_egid()) {
+		current->pdeath_signal = 0;
+	} else if (file_permission(bprm->file, MAY_READ) ||
+		   bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP) {
+		set_dumpable(current->mm, suid_dumpable);
+	}
+
+	/*
+	 * Flush performance counters when crossing a
+	 * security domain:
+	 */
+	if (!get_dumpable(current->mm))
+		perf_event_exit_task(current);
+
+	/* An exec changes our domain. We are no longer part of the thread
+	   group */
+
+	current->self_exec_id++;
+			
+	flush_signal_handlers(current, 0);
+	flush_old_files(current->files);
+}
+EXPORT_SYMBOL(setup_new_exec);
+
+/*
+ * Prepare credentials and lock ->cred_guard_mutex.
+ * install_exec_creds() commits the new creds and drops the lock.
+ * Or, if exec fails before, free_bprm() should release ->cred and
+ * and unlock.
+ */
+int prepare_bprm_creds(struct linux_binprm *bprm)
+{
+	if (mutex_lock_interruptible(&current->signal->cred_guard_mutex))
+		return -ERESTARTNOINTR;
+
+	bprm->cred = prepare_exec_creds();
+	if (likely(bprm->cred))
+		return 0;
+
+	mutex_unlock(&current->signal->cred_guard_mutex);
+	return -ENOMEM;
+}
+
+void free_bprm(struct linux_binprm *bprm)
+{
+	free_arg_pages(bprm);
+	if (bprm->cred) {
+		mutex_unlock(&current->signal->cred_guard_mutex);
+		abort_creds(bprm->cred);
+	}
+	kfree(bprm);
+}
+
+/*
+ * install the new credentials for this executable
+ */
+void install_exec_creds(struct linux_binprm *bprm)
+{
+	security_bprm_committing_creds(bprm);
+
+	commit_creds(bprm->cred);
+	bprm->cred = NULL;
+	/*
+	 * cred_guard_mutex must be held at least to this point to prevent
+	 * ptrace_attach() from altering our determination of the task's
+	 * credentials; any time after this it may be unlocked.
+	 */
+	security_bprm_committed_creds(bprm);
+	mutex_unlock(&current->signal->cred_guard_mutex);
+}
+EXPORT_SYMBOL(install_exec_creds);
+
+/*
+ * determine how safe it is to execute the proposed program
+ * - the caller must hold ->cred_guard_mutex to protect against
+ *   PTRACE_ATTACH
+ */
+int check_unsafe_exec(struct linux_binprm *bprm)
+{
+	struct task_struct *p = current, *t;
+	unsigned n_fs;
+	int res = 0;
+
+	bprm->unsafe = tracehook_unsafe_exec(p);
+
+	n_fs = 1;
+	spin_lock(&p->fs->lock);
+	rcu_read_lock();
+	for (t = next_thread(p); t != p; t = next_thread(t)) {
+		if (t->fs == p->fs)
+			n_fs++;
+	}
+	rcu_read_unlock();
+
+	if (p->fs->users > n_fs) {
+		bprm->unsafe |= LSM_UNSAFE_SHARE;
+	} else {
+		res = -EAGAIN;
+		if (!p->fs->in_exec) {
+			p->fs->in_exec = 1;
+			res = 1;
+		}
+	}
+	spin_unlock(&p->fs->lock);
+
+	return res;
+}
+
+/* 
+ * Fill the binprm structure from the inode. 
+ * Check permissions, then read the first 128 (BINPRM_BUF_SIZE) bytes
+ *
+ * This may be called multiple times for binary chains (scripts for example).
+ */
+int prepare_binprm(struct linux_binprm *bprm)
+{
+	umode_t mode;
+	struct inode * inode = bprm->file->f_path.dentry->d_inode;
+	int retval;
+
+	mode = inode->i_mode;
+	if (bprm->file->f_op == NULL)
+		return -EACCES;
+
+	/* clear any previous set[ug]id data from a previous binary */
+	bprm->cred->euid = current_euid();
+	bprm->cred->egid = current_egid();
+
+	if (!(bprm->file->f_path.mnt->mnt_flags & MNT_NOSUID)) {
+		/* Set-uid? */
+		if (mode & S_ISUID) {
+			bprm->per_clear |= PER_CLEAR_ON_SETID;
+			bprm->cred->euid = inode->i_uid;
+		}
+
+		/* Set-gid? */
+		/*
+		 * If setgid is set but no group execute bit then this
+		 * is a candidate for mandatory locking, not a setgid
+		 * executable.
+		 */
+		if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
+			bprm->per_clear |= PER_CLEAR_ON_SETID;
+			bprm->cred->egid = inode->i_gid;
+		}
+	}
+
+	/* fill in binprm security blob */
+	retval = security_bprm_set_creds(bprm);
+	if (retval)
+		return retval;
+	bprm->cred_prepared = 1;
+
+	memset(bprm->buf, 0, BINPRM_BUF_SIZE);
+	return kernel_read(bprm->file, 0, bprm->buf, BINPRM_BUF_SIZE);
+}
+
+EXPORT_SYMBOL(prepare_binprm);
+
+/*
+ * Arguments are '\0' separated strings found at the location bprm->p
+ * points to; chop off the first by relocating brpm->p to right after
+ * the first '\0' encountered.
+ */
+int remove_arg_zero(struct linux_binprm *bprm)
+{
+	int ret = 0;
+	unsigned long offset;
+	char *kaddr;
+	struct page *page;
+
+	if (!bprm->argc)
+		return 0;
+
+	do {
+		offset = bprm->p & ~PAGE_MASK;
+		page = get_arg_page(bprm, bprm->p, 0);
+		if (!page) {
+			ret = -EFAULT;
+			goto out;
+		}
+		kaddr = kmap_atomic(page, KM_USER0);
+
+		for (; offset < PAGE_SIZE && kaddr[offset];
+				offset++, bprm->p++)
+			;
+
+		kunmap_atomic(kaddr, KM_USER0);
+		put_arg_page(page);
+
+		if (offset == PAGE_SIZE)
+			free_arg_page(bprm, (bprm->p >> PAGE_SHIFT) - 1);
+	} while (offset == PAGE_SIZE);
+
+	bprm->p++;
+	bprm->argc--;
+	ret = 0;
+
+out:
+	return ret;
+}
+EXPORT_SYMBOL(remove_arg_zero);
+
+/*
+ * cycle the list of binary formats handler, until one recognizes the image
+ */
+int search_binary_handler(struct linux_binprm *bprm,struct pt_regs *regs)
+{
+	unsigned int depth = bprm->recursion_depth;
+	int try,retval;
+	struct linux_binfmt *fmt;
+
+	retval = security_bprm_check(bprm);
+	if (retval)
+		return retval;
+
+	retval = audit_bprm(bprm);
+	if (retval)
+		return retval;
+
+	retval = -ENOENT;
+	for (try=0; try<2; try++) {
+		read_lock(&binfmt_lock);
+		list_for_each_entry(fmt, &formats, lh) {
+			int (*fn)(struct linux_binprm *, struct pt_regs *) = fmt->load_binary;
+			if (!fn)
+				continue;
+			if (!try_module_get(fmt->module))
+				continue;
+			read_unlock(&binfmt_lock);
+			retval = fn(bprm, regs);
+			/*
+			 * Restore the depth counter to its starting value
+			 * in this call, so we don't have to rely on every
+			 * load_binary function to restore it on return.
+			 */
+			bprm->recursion_depth = depth;
+			if (retval >= 0) {
+				if (depth == 0)
+					tracehook_report_exec(fmt, bprm, regs);
+				put_binfmt(fmt);
+				allow_write_access(bprm->file);
+				if (bprm->file)
+					fput(bprm->file);
+				bprm->file = NULL;
+				current->did_exec = 1;
+				proc_exec_connector(current);
+				return retval;
+			}
+			read_lock(&binfmt_lock);
+			put_binfmt(fmt);
+			if (retval != -ENOEXEC || bprm->mm == NULL)
+				break;
+			if (!bprm->file) {
+				read_unlock(&binfmt_lock);
+				return retval;
+			}
+		}
+		read_unlock(&binfmt_lock);
+		if (retval != -ENOEXEC || bprm->mm == NULL) {
+			break;
+#ifdef CONFIG_MODULES
+		} else {
+#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
+			if (printable(bprm->buf[0]) &&
+			    printable(bprm->buf[1]) &&
+			    printable(bprm->buf[2]) &&
+			    printable(bprm->buf[3]))
+				break; /* -ENOEXEC */
+			if (try)
+				break; /* -ENOEXEC */
+			request_module("binfmt-%04x", *(unsigned short *)(&bprm->buf[2]));
+#endif
+		}
+	}
+	return retval;
+}
+
+EXPORT_SYMBOL(search_binary_handler);
+
+/*
+ * sys_execve() executes a new program.
+ */
+static int do_execve_common(const char *filename,
+				struct user_arg_ptr argv,
+				struct user_arg_ptr envp,
+				struct pt_regs *regs)
+{
+	struct linux_binprm *bprm;
+	struct file *file;
+	struct files_struct *displaced;
+	bool clear_in_exec;
+	int retval;
+
+	retval = unshare_files(&displaced);
+	if (retval)
+		goto out_ret;
+
+	retval = -ENOMEM;
+	bprm = kzalloc(sizeof(*bprm), GFP_KERNEL);
+	if (!bprm)
+		goto out_files;
+
+	retval = prepare_bprm_creds(bprm);
+	if (retval)
+		goto out_free;
+
+	retval = check_unsafe_exec(bprm);
+	if (retval < 0)
+		goto out_free;
+	clear_in_exec = retval;
+	current->in_execve = 1;
+
+	file = open_exec(filename);
+	retval = PTR_ERR(file);
+	if (IS_ERR(file))
+		goto out_unmark;
+
+	sched_exec();
+
+	bprm->file = file;
+	bprm->filename = filename;
+	bprm->interp = filename;
+
+	retval = bprm_mm_init(bprm);
+	if (retval)
+		goto out_file;
+
+	bprm->argc = count(argv, MAX_ARG_STRINGS);
+	if ((retval = bprm->argc) < 0)
+		goto out;
+
+	bprm->envc = count(envp, MAX_ARG_STRINGS);
+	if ((retval = bprm->envc) < 0)
+		goto out;
+
+	retval = prepare_binprm(bprm);
+	if (retval < 0)
+		goto out;
+
+	retval = copy_strings_kernel(1, &bprm->filename, bprm);
+	if (retval < 0)
+		goto out;
+
+	bprm->exec = bprm->p;
+	retval = copy_strings(bprm->envc, envp, bprm);
+	if (retval < 0)
+		goto out;
+
+	retval = copy_strings(bprm->argc, argv, bprm);
+	if (retval < 0)
+		goto out;
+
+	retval = search_binary_handler(bprm,regs);
+	if (retval < 0)
+		goto out;
+
+	/* execve succeeded */
+	current->fs->in_exec = 0;
+	current->in_execve = 0;
+	acct_update_integrals(current);
+	free_bprm(bprm);
+	if (displaced)
+		put_files_struct(displaced);
+	return retval;
+
+out:
+	if (bprm->mm) {
+		acct_arg_size(bprm, 0);
+		mmput(bprm->mm);
+	}
+
+out_file:
+	if (bprm->file) {
+		allow_write_access(bprm->file);
+		fput(bprm->file);
+	}
+
+out_unmark:
+	if (clear_in_exec)
+		current->fs->in_exec = 0;
+	current->in_execve = 0;
+
+out_free:
+	free_bprm(bprm);
+
+out_files:
+	if (displaced)
+		reset_files_struct(displaced);
+out_ret:
+	return retval;
+}
+
+int do_execve(const char *filename,
+	const char __user *const __user *__argv,
+	const char __user *const __user *__envp,
+	struct pt_regs *regs)
+{
+	struct user_arg_ptr argv = { .ptr.native = __argv };
+	struct user_arg_ptr envp = { .ptr.native = __envp };
+	return do_execve_common(filename, argv, envp, regs);
+}
+
+#ifdef CONFIG_COMPAT
+int compat_do_execve(char *filename,
+	compat_uptr_t __user *__argv,
+	compat_uptr_t __user *__envp,
+	struct pt_regs *regs)
+{
+	struct user_arg_ptr argv = {
+		.is_compat = true,
+		.ptr.compat = __argv,
+	};
+	struct user_arg_ptr envp = {
+		.is_compat = true,
+		.ptr.compat = __envp,
+	};
+	return do_execve_common(filename, argv, envp, regs);
+}
+#endif
+
+void set_binfmt(struct linux_binfmt *new)
+{
+	struct mm_struct *mm = current->mm;
+
+	if (mm->binfmt)
+		module_put(mm->binfmt->module);
+
+	mm->binfmt = new;
+	if (new)
+		__module_get(new->module);
+}
+
+EXPORT_SYMBOL(set_binfmt);
+
+static int expand_corename(struct core_name *cn)
+{
+	char *old_corename = cn->corename;
+
+	cn->size = CORENAME_MAX_SIZE * atomic_inc_return(&call_count);
+	cn->corename = krealloc(old_corename, cn->size, GFP_KERNEL);
+
+	if (!cn->corename) {
+		kfree(old_corename);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static int cn_printf(struct core_name *cn, const char *fmt, ...)
+{
+	char *cur;
+	int need;
+	int ret;
+	va_list arg;
+
+	va_start(arg, fmt);
+	need = vsnprintf(NULL, 0, fmt, arg);
+	va_end(arg);
+
+	if (likely(need < cn->size - cn->used - 1))
+		goto out_printf;
+
+	ret = expand_corename(cn);
+	if (ret)
+		goto expand_fail;
+
+out_printf:
+	cur = cn->corename + cn->used;
+	va_start(arg, fmt);
+	vsnprintf(cur, need + 1, fmt, arg);
+	va_end(arg);
+	cn->used += need;
+	return 0;
+
+expand_fail:
+	return ret;
+}
+
+static int cn_print_exe_file(struct core_name *cn)
+{
+	struct file *exe_file;
+	char *pathbuf, *path, *p;
+	int ret;
+
+	exe_file = get_mm_exe_file(current->mm);
+	if (!exe_file)
+		return cn_printf(cn, "(unknown)");
+
+	pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY);
+	if (!pathbuf) {
+		ret = -ENOMEM;
+		goto put_exe_file;
+	}
+
+	path = d_path(&exe_file->f_path, pathbuf, PATH_MAX);
+	if (IS_ERR(path)) {
+		ret = PTR_ERR(path);
+		goto free_buf;
+	}
+
+	for (p = path; *p; p++)
+		if (*p == '/')
+			*p = '!';
+
+	ret = cn_printf(cn, "%s", path);
+
+free_buf:
+	kfree(pathbuf);
+put_exe_file:
+	fput(exe_file);
+	return ret;
+}
+
+/* format_corename will inspect the pattern parameter, and output a
+ * name into corename, which must have space for at least
+ * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
+ */
+static int format_corename(struct core_name *cn, long signr)
+{
+	const struct cred *cred = current_cred();
+	const char *pat_ptr = core_pattern;
+	int ispipe = (*pat_ptr == '|');
+	int pid_in_pattern = 0;
+	int err = 0;
+
+	cn->size = CORENAME_MAX_SIZE * atomic_read(&call_count);
+	cn->corename = kmalloc(cn->size, GFP_KERNEL);
+	cn->used = 0;
+
+	if (!cn->corename)
+		return -ENOMEM;
+
+	/* Repeat as long as we have more pattern to process and more output
+	   space */
+	while (*pat_ptr) {
+		if (*pat_ptr != '%') {
+			if (*pat_ptr == 0)
+				goto out;
+			err = cn_printf(cn, "%c", *pat_ptr++);
+		} else {
+			switch (*++pat_ptr) {
+			/* single % at the end, drop that */
+			case 0:
+				goto out;
+			/* Double percent, output one percent */
+			case '%':
+				err = cn_printf(cn, "%c", '%');
+				break;
+			/* pid */
+			case 'p':
+				pid_in_pattern = 1;
+				err = cn_printf(cn, "%d",
+					      task_tgid_vnr(current));
+				break;
+			/* uid */
+			case 'u':
+				err = cn_printf(cn, "%d", cred->uid);
+				break;
+			/* gid */
+			case 'g':
+				err = cn_printf(cn, "%d", cred->gid);
+				break;
+			/* signal that caused the coredump */
+			case 's':
+				err = cn_printf(cn, "%ld", signr);
+				break;
+			/* UNIX time of coredump */
+			case 't': {
+				struct timeval tv;
+				do_gettimeofday(&tv);
+				err = cn_printf(cn, "%lu", tv.tv_sec);
+				break;
+			}
+			/* hostname */
+			case 'h':
+				down_read(&uts_sem);
+				err = cn_printf(cn, "%s",
+					      utsname()->nodename);
+				up_read(&uts_sem);
+				break;
+			/* executable */
+			case 'e':
+				err = cn_printf(cn, "%s", current->comm);
+				break;
+			case 'E':
+				err = cn_print_exe_file(cn);
+				break;
+			/* core limit size */
+			case 'c':
+				err = cn_printf(cn, "%lu",
+					      rlimit(RLIMIT_CORE));
+				break;
+			default:
+				break;
+			}
+			++pat_ptr;
+		}
+
+		if (err)
+			return err;
+	}
+
+	/* Backward compatibility with core_uses_pid:
+	 *
+	 * If core_pattern does not include a %p (as is the default)
+	 * and core_uses_pid is set, then .%pid will be appended to
+	 * the filename. Do not do this for piped commands. */
+	if (!ispipe && !pid_in_pattern && core_uses_pid) {
+		err = cn_printf(cn, ".%d", task_tgid_vnr(current));
+		if (err)
+			return err;
+	}
+out:
+	return ispipe;
+}
+
+static int zap_process(struct task_struct *start, int exit_code)
+{
+	struct task_struct *t;
+	int nr = 0;
+
+	start->signal->flags = SIGNAL_GROUP_EXIT;
+	start->signal->group_exit_code = exit_code;
+	start->signal->group_stop_count = 0;
+
+	t = start;
+	do {
+		task_clear_group_stop_pending(t);
+		if (t != current && t->mm) {
+			sigaddset(&t->pending.signal, SIGKILL);
+			signal_wake_up(t, 1);
+			nr++;
+		}
+	} while_each_thread(start, t);
+
+	return nr;
+}
+
+static inline int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
+				struct core_state *core_state, int exit_code)
+{
+	struct task_struct *g, *p;
+	unsigned long flags;
+	int nr = -EAGAIN;
+
+	spin_lock_irq(&tsk->sighand->siglock);
+	if (!signal_group_exit(tsk->signal)) {
+		mm->core_state = core_state;
+		nr = zap_process(tsk, exit_code);
+	}
+	spin_unlock_irq(&tsk->sighand->siglock);
+	if (unlikely(nr < 0))
+		return nr;
+
+	if (atomic_read(&mm->mm_users) == nr + 1)
+		goto done;
+	/*
+	 * We should find and kill all tasks which use this mm, and we should
+	 * count them correctly into ->nr_threads. We don't take tasklist
+	 * lock, but this is safe wrt:
+	 *
+	 * fork:
+	 *	None of sub-threads can fork after zap_process(leader). All
+	 *	processes which were created before this point should be
+	 *	visible to zap_threads() because copy_process() adds the new
+	 *	process to the tail of init_task.tasks list, and lock/unlock
+	 *	of ->siglock provides a memory barrier.
+	 *
+	 * do_exit:
+	 *	The caller holds mm->mmap_sem. This means that the task which
+	 *	uses this mm can't pass exit_mm(), so it can't exit or clear
+	 *	its ->mm.
+	 *
+	 * de_thread:
+	 *	It does list_replace_rcu(&leader->tasks, &current->tasks),
+	 *	we must see either old or new leader, this does not matter.
+	 *	However, it can change p->sighand, so lock_task_sighand(p)
+	 *	must be used. Since p->mm != NULL and we hold ->mmap_sem
+	 *	it can't fail.
+	 *
+	 *	Note also that "g" can be the old leader with ->mm == NULL
+	 *	and already unhashed and thus removed from ->thread_group.
+	 *	This is OK, __unhash_process()->list_del_rcu() does not
+	 *	clear the ->next pointer, we will find the new leader via
+	 *	next_thread().
+	 */
+	rcu_read_lock();
+	for_each_process(g) {
+		if (g == tsk->group_leader)
+			continue;
+		if (g->flags & PF_KTHREAD)
+			continue;
+		p = g;
+		do {
+			if (p->mm) {
+				if (unlikely(p->mm == mm)) {
+					lock_task_sighand(p, &flags);
+					nr += zap_process(p, exit_code);
+					unlock_task_sighand(p, &flags);
+				}
+				break;
+			}
+		} while_each_thread(g, p);
+	}
+	rcu_read_unlock();
+done:
+	atomic_set(&core_state->nr_threads, nr);
+	return nr;
+}
+
+static int coredump_wait(int exit_code, struct core_state *core_state)
+{
+	struct task_struct *tsk = current;
+	struct mm_struct *mm = tsk->mm;
+	struct completion *vfork_done;
+	int core_waiters = -EBUSY;
+
+	init_completion(&core_state->startup);
+	core_state->dumper.task = tsk;
+	core_state->dumper.next = NULL;
+
+	down_write(&mm->mmap_sem);
+	if (!mm->core_state)
+		core_waiters = zap_threads(tsk, mm, core_state, exit_code);
+	up_write(&mm->mmap_sem);
+
+	if (unlikely(core_waiters < 0))
+		goto fail;
+
+	/*
+	 * Make sure nobody is waiting for us to release the VM,
+	 * otherwise we can deadlock when we wait on each other
+	 */
+	vfork_done = tsk->vfork_done;
+	if (vfork_done) {
+		tsk->vfork_done = NULL;
+		complete(vfork_done);
+	}
+
+	if (core_waiters)
+		wait_for_completion(&core_state->startup);
+fail:
+	return core_waiters;
+}
+
+static void coredump_finish(struct mm_struct *mm)
+{
+	struct core_thread *curr, *next;
+	struct task_struct *task;
+
+	next = mm->core_state->dumper.next;
+	while ((curr = next) != NULL) {
+		next = curr->next;
+		task = curr->task;
+		/*
+		 * see exit_mm(), curr->task must not see
+		 * ->task == NULL before we read ->next.
+		 */
+		smp_mb();
+		curr->task = NULL;
+		wake_up_process(task);
+	}
+
+	mm->core_state = NULL;
+}
+
+/*
+ * set_dumpable converts traditional three-value dumpable to two flags and
+ * stores them into mm->flags.  It modifies lower two bits of mm->flags, but
+ * these bits are not changed atomically.  So get_dumpable can observe the
+ * intermediate state.  To avoid doing unexpected behavior, get get_dumpable
+ * return either old dumpable or new one by paying attention to the order of
+ * modifying the bits.
+ *
+ * dumpable |   mm->flags (binary)
+ * old  new | initial interim  final
+ * ---------+-----------------------
+ *  0    1  |   00      01      01
+ *  0    2  |   00      10(*)   11
+ *  1    0  |   01      00      00
+ *  1    2  |   01      11      11
+ *  2    0  |   11      10(*)   00
+ *  2    1  |   11      11      01
+ *
+ * (*) get_dumpable regards interim value of 10 as 11.
+ */
+void set_dumpable(struct mm_struct *mm, int value)
+{
+	switch (value) {
+	case 0:
+		clear_bit(MMF_DUMPABLE, &mm->flags);
+		smp_wmb();
+		clear_bit(MMF_DUMP_SECURELY, &mm->flags);
+		break;
+	case 1:
+		set_bit(MMF_DUMPABLE, &mm->flags);
+		smp_wmb();
+		clear_bit(MMF_DUMP_SECURELY, &mm->flags);
+		break;
+	case 2:
+		set_bit(MMF_DUMP_SECURELY, &mm->flags);
+		smp_wmb();
+		set_bit(MMF_DUMPABLE, &mm->flags);
+		break;
+	}
+}
+
+static int __get_dumpable(unsigned long mm_flags)
+{
+	int ret;
+
+	ret = mm_flags & MMF_DUMPABLE_MASK;
+	return (ret >= 2) ? 2 : ret;
+}
+
+int get_dumpable(struct mm_struct *mm)
+{
+	return __get_dumpable(mm->flags);
+}
+
+static void wait_for_dump_helpers(struct file *file)
+{
+	struct pipe_inode_info *pipe;
+
+	pipe = file->f_path.dentry->d_inode->i_pipe;
+
+	pipe_lock(pipe);
+	pipe->readers++;
+	pipe->writers--;
+
+	while ((pipe->readers > 1) && (!signal_pending(current))) {
+		wake_up_interruptible_sync(&pipe->wait);
+		kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
+		pipe_wait(pipe);
+	}
+
+	pipe->readers--;
+	pipe->writers++;
+	pipe_unlock(pipe);
+
+}
+
+
+/*
+ * umh_pipe_setup
+ * helper function to customize the process used
+ * to collect the core in userspace.  Specifically
+ * it sets up a pipe and installs it as fd 0 (stdin)
+ * for the process.  Returns 0 on success, or
+ * PTR_ERR on failure.
+ * Note that it also sets the core limit to 1.  This
+ * is a special value that we use to trap recursive
+ * core dumps
+ */
+static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
+{
+	struct file *rp, *wp;
+	struct fdtable *fdt;
+	struct coredump_params *cp = (struct coredump_params *)info->data;
+	struct files_struct *cf = current->files;
+
+	wp = create_write_pipe(0);
+	if (IS_ERR(wp))
+		return PTR_ERR(wp);
+
+	rp = create_read_pipe(wp, 0);
+	if (IS_ERR(rp)) {
+		free_write_pipe(wp);
+		return PTR_ERR(rp);
+	}
+
+	cp->file = wp;
+
+	sys_close(0);
+	fd_install(0, rp);
+	spin_lock(&cf->file_lock);
+	fdt = files_fdtable(cf);
+	FD_SET(0, fdt->open_fds);
+	FD_CLR(0, fdt->close_on_exec);
+	spin_unlock(&cf->file_lock);
+
+	/* and disallow core files too */
+	current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1};
+
+	return 0;
+}
+
+void do_coredump(long signr, int exit_code, struct pt_regs *regs)
+{
+	struct core_state core_state;
+	struct core_name cn;
+	struct mm_struct *mm = current->mm;
+	struct linux_binfmt * binfmt;
+	const struct cred *old_cred;
+	struct cred *cred;
+	int retval = 0;
+	int flag = 0;
+	int ispipe;
+	static atomic_t core_dump_count = ATOMIC_INIT(0);
+	struct coredump_params cprm = {
+		.signr = signr,
+		.regs = regs,
+		.limit = rlimit(RLIMIT_CORE),
+		/*
+		 * We must use the same mm->flags while dumping core to avoid
+		 * inconsistency of bit flags, since this flag is not protected
+		 * by any locks.
+		 */
+		.mm_flags = mm->flags,
+	};
+
+	audit_core_dumps(signr);
+
+	binfmt = mm->binfmt;
+	if (!binfmt || !binfmt->core_dump)
+		goto fail;
+	if (!__get_dumpable(cprm.mm_flags))
+		goto fail;
+
+	cred = prepare_creds();
+	if (!cred)
+		goto fail;
+	/*
+	 *	We cannot trust fsuid as being the "true" uid of the
+	 *	process nor do we know its entire history. We only know it
+	 *	was tainted so we dump it as root in mode 2.
+	 */
+	if (__get_dumpable(cprm.mm_flags) == 2) {
+		/* Setuid core dump mode */
+		flag = O_EXCL;		/* Stop rewrite attacks */
+		cred->fsuid = 0;	/* Dump root private */
+	}
+
+	retval = coredump_wait(exit_code, &core_state);
+	if (retval < 0)
+		goto fail_creds;
+
+	old_cred = override_creds(cred);
+
+	/*
+	 * Clear any false indication of pending signals that might
+	 * be seen by the filesystem code called to write the core file.
+	 */
+	clear_thread_flag(TIF_SIGPENDING);
+
+	ispipe = format_corename(&cn, signr);
+
+	if (ispipe == -ENOMEM) {
+		printk(KERN_WARNING "format_corename failed\n");
+		printk(KERN_WARNING "Aborting core\n");
+		goto fail_corename;
+	}
+
+ 	if (ispipe) {
+		int dump_count;
+		char **helper_argv;
+
+		if (cprm.limit == 1) {
+			/*
+			 * Normally core limits are irrelevant to pipes, since
+			 * we're not writing to the file system, but we use
+			 * cprm.limit of 1 here as a speacial value. Any
+			 * non-1 limit gets set to RLIM_INFINITY below, but
+			 * a limit of 0 skips the dump.  This is a consistent
+			 * way to catch recursive crashes.  We can still crash
+			 * if the core_pattern binary sets RLIM_CORE =  !1
+			 * but it runs as root, and can do lots of stupid things
+			 * Note that we use task_tgid_vnr here to grab the pid
+			 * of the process group leader.  That way we get the
+			 * right pid if a thread in a multi-threaded
+			 * core_pattern process dies.
+			 */
+			printk(KERN_WARNING
+				"Process %d(%s) has RLIMIT_CORE set to 1\n",
+				task_tgid_vnr(current), current->comm);
+			printk(KERN_WARNING "Aborting core\n");
+			goto fail_unlock;
+		}
+		cprm.limit = RLIM_INFINITY;
+
+		dump_count = atomic_inc_return(&core_dump_count);
+		if (core_pipe_limit && (core_pipe_limit < dump_count)) {
+			printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n",
+			       task_tgid_vnr(current), current->comm);
+			printk(KERN_WARNING "Skipping core dump\n");
+			goto fail_dropcount;
+		}
+
+		helper_argv = argv_split(GFP_KERNEL, cn.corename+1, NULL);
+		if (!helper_argv) {
+			printk(KERN_WARNING "%s failed to allocate memory\n",
+			       __func__);
+			goto fail_dropcount;
+		}
+
+		retval = call_usermodehelper_fns(helper_argv[0], helper_argv,
+					NULL, UMH_WAIT_EXEC, umh_pipe_setup,
+					NULL, &cprm);
+		argv_free(helper_argv);
+		if (retval) {
+ 			printk(KERN_INFO "Core dump to %s pipe failed\n",
+			       cn.corename);
+			goto close_fail;
+ 		}
+	} else {
+		struct inode *inode;
+
+		if (cprm.limit < binfmt->min_coredump)
+			goto fail_unlock;
+
+		cprm.file = filp_open(cn.corename,
+				 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
+				 0600);
+		if (IS_ERR(cprm.file))
+			goto fail_unlock;
+
+		inode = cprm.file->f_path.dentry->d_inode;
+		if (inode->i_nlink > 1)
+			goto close_fail;
+		if (d_unhashed(cprm.file->f_path.dentry))
+			goto close_fail;
+		/*
+		 * AK: actually i see no reason to not allow this for named
+		 * pipes etc, but keep the previous behaviour for now.
+		 */
+		if (!S_ISREG(inode->i_mode))
+			goto close_fail;
+		/*
+		 * Dont allow local users get cute and trick others to coredump
+		 * into their pre-created files.
+		 */
+		if (inode->i_uid != current_fsuid())
+			goto close_fail;
+		if (!cprm.file->f_op || !cprm.file->f_op->write)
+			goto close_fail;
+		if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file))
+			goto close_fail;
+	}
+
+	retval = binfmt->core_dump(&cprm);
+	if (retval)
+		current->signal->group_exit_code |= 0x80;
+
+	if (ispipe && core_pipe_limit)
+		wait_for_dump_helpers(cprm.file);
+close_fail:
+	if (cprm.file)
+		filp_close(cprm.file, NULL);
+fail_dropcount:
+	if (ispipe)
+		atomic_dec(&core_dump_count);
+fail_unlock:
+	kfree(cn.corename);
+fail_corename:
+	coredump_finish(mm);
+	revert_creds(old_cred);
+fail_creds:
+	put_cred(cred);
+fail:
+	return;
+}
+
+/*
+ * Core dumping helper functions.  These are the only things you should
+ * do on a core-file: use only these functions to write out all the
+ * necessary info.
+ */
+int dump_write(struct file *file, const void *addr, int nr)
+{
+	return access_ok(VERIFY_READ, addr, nr) && file->f_op->write(file, addr, nr, &file->f_pos) == nr;
+}
+EXPORT_SYMBOL(dump_write);
+
+int dump_seek(struct file *file, loff_t off)
+{
+	int ret = 1;
+
+	if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
+		if (file->f_op->llseek(file, off, SEEK_CUR) < 0)
+			return 0;
+	} 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)) {
+				ret = 0;
+				break;
+			}
+			off -= n;
+		}
+		free_page((unsigned long)buf);
+	}
+	return ret;
+}
+EXPORT_SYMBOL(dump_seek);