Initial import

1 files changed, 1751 insertions, 0 deletions

diff --git a/fs/exec.c b/fs/exec.c
new file mode 100644
index 000000000..6f28db024
--- /dev/null
+++ b/fs/exec.c
@@ -0,0 +1,1751 @@
+/*
+ *  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/vmacache.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 <linux/ksm.h>
+
+#include <trace/events/fs.h>
+
+#include <asm/uaccess.h>
+#include <asm/mmu_context.h>
+#include <asm/tlb.h>
+
+#include <trace/events/task.h>
+#include "internal.h"
+
+#include <trace/events/sched.h>
+
+int suid_dumpable = 0;
+
+static LIST_HEAD(formats);
+static DEFINE_RWLOCK(binfmt_lock);
+
+void __register_binfmt(struct linux_binfmt * fmt, int insert)
+{
+	BUG_ON(!fmt);
+	if (WARN_ON(!fmt->load_binary))
+		return;
+	write_lock(&binfmt_lock);
+	insert ? list_add(&fmt->lh, &formats) :
+		 list_add_tail(&fmt->lh, &formats);
+	write_unlock(&binfmt_lock);
+}
+
+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);
+}
+
+#ifdef CONFIG_USELIB
+/*
+ * 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 linux_binfmt *fmt;
+	struct file *file;
+	struct filename *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,
+		.lookup_flags = LOOKUP_FOLLOW,
+	};
+
+	if (IS_ERR(tmp))
+		goto out;
+
+	file = do_filp_open(AT_FDCWD, tmp, &uselib_flags);
+	putname(tmp);
+	error = PTR_ERR(file);
+	if (IS_ERR(file))
+		goto out;
+
+	error = -EINVAL;
+	if (!S_ISREG(file_inode(file)->i_mode))
+		goto exit;
+
+	error = -EACCES;
+	if (file->f_path.mnt->mnt_flags & MNT_NOEXEC)
+		goto exit;
+
+	fsnotify_open(file);
+
+	error = -ENOEXEC;
+
+	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;
+}
+#endif /* #ifdef CONFIG_USELIB */
+
+#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;
+	add_mm_counter(mm, MM_ANONPAGES, diff);
+}
+
+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.
+	 */
+	BUILD_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_SOFTDIRTY | 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 = insert_vm_struct(mm, vma);
+	if (err)
+		goto err;
+
+	mm->stack_vm = mm->total_vm = 1;
+	arch_bprm_mm_init(mm, vma);
+	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().
+ */
+static 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 = __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
+		const 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;
+			++i;
+
+			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, false))
+		return -ENOMEM;
+
+	lru_add_drain();
+	tlb_gather_mmu(&tlb, mm, old_start, old_end);
+	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 : USER_PGTABLES_CEILING);
+	} 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 : USER_PGTABLES_CEILING);
+	}
+	tlb_finish_mmu(&tlb, old_start, 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 */
+	stack_base = rlimit_max(RLIMIT_STACK);
+	if (stack_base > STACK_SIZE_MAX)
+		stack_base = STACK_SIZE_MAX;
+
+	/* Add space for stack randomization. */
+	stack_base += (STACK_RND_MASK << PAGE_SHIFT);
+
+	/* 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 */
+
+static struct file *do_open_execat(int fd, struct filename *name, int flags)
+{
+	struct file *file;
+	int err;
+	struct open_flags open_exec_flags = {
+		.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
+		.acc_mode = MAY_EXEC | MAY_OPEN,
+		.intent = LOOKUP_OPEN,
+		.lookup_flags = LOOKUP_FOLLOW,
+	};
+
+	if ((flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
+		return ERR_PTR(-EINVAL);
+	if (flags & AT_SYMLINK_NOFOLLOW)
+		open_exec_flags.lookup_flags &= ~LOOKUP_FOLLOW;
+	if (flags & AT_EMPTY_PATH)
+		open_exec_flags.lookup_flags |= LOOKUP_EMPTY;
+
+	file = do_filp_open(fd, name, &open_exec_flags);
+	if (IS_ERR(file))
+		goto out;
+
+	err = -EACCES;
+	if (!S_ISREG(file_inode(file)->i_mode))
+		goto exit;
+
+	if (file->f_path.mnt->mnt_flags & MNT_NOEXEC)
+		goto exit;
+
+	err = deny_write_access(file);
+	if (err)
+		goto exit;
+
+	if (name->name[0] != '\0') {
+		fsnotify_open(file);
+		trace_open_exec(name->name);
+	}
+
+out:
+	return file;
+
+exit:
+	fput(file);
+	return ERR_PTR(err);
+}
+
+struct file *open_exec(const char *name)
+{
+	struct filename *filename = getname_kernel(name);
+	struct file *f = ERR_CAST(filename);
+
+	if (!IS_ERR(filename)) {
+		f = do_open_execat(AT_FDCWD, filename, 0);
+		putname(filename);
+	}
+	return f;
+}
+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);
+
+ssize_t read_code(struct file *file, unsigned long addr, loff_t pos, size_t len)
+{
+	ssize_t res = vfs_read(file, (void __user *)addr, len, &pos);
+	if (res > 0)
+		flush_icache_range(addr, addr + len);
+	return res;
+}
+EXPORT_SYMBOL(read_code);
+
+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;
+	mm_release(tsk, old_mm);
+
+	if (old_mm) {
+		sync_mm_rss(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);
+	tsk->mm->vmacache_seqnum = 0;
+	vmacache_flush(tsk);
+	task_unlock(tsk);
+	if (old_mm) {
+		up_read(&old_mm->mmap_sem);
+		BUG_ON(active_mm != old_mm);
+		setmax_mm_hiwater_rss(&tsk->signal->maxrss, 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_KILLABLE);
+		spin_unlock_irq(lock);
+		schedule();
+		if (unlikely(__fatal_signal_pending(tsk)))
+			goto killed;
+		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;
+
+		for (;;) {
+			threadgroup_change_begin(tsk);
+			write_lock_irq(&tasklist_lock);
+			/*
+			 * Do this under tasklist_lock to ensure that
+			 * exit_notify() can't miss ->group_exit_task
+			 */
+			sig->notify_count = -1;
+			if (likely(leader->exit_state))
+				break;
+			__set_current_state(TASK_KILLABLE);
+			write_unlock_irq(&tasklist_lock);
+			threadgroup_change_end(tsk);
+			schedule();
+			if (unlikely(__fatal_signal_pending(tsk)))
+				goto killed;
+		}
+
+		/*
+		 * 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;
+		tsk->real_start_time = leader->real_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.
+		 */
+		tsk->pid = leader->pid;
+		change_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;
+		leader->exit_signal = -1;
+
+		BUG_ON(leader->exit_state != EXIT_ZOMBIE);
+		leader->exit_state = EXIT_DEAD;
+
+		/*
+		 * We are going to release_task()->ptrace_unlink() silently,
+		 * the tracer can sleep in do_wait(). EXIT_DEAD guarantees
+		 * the tracer wont't block again waiting for this thread.
+		 */
+		if (unlikely(leader->ptrace))
+			__wake_up_parent(leader, leader->parent);
+		write_unlock_irq(&tasklist_lock);
+		threadgroup_change_end(tsk);
+
+		release_task(leader);
+	}
+
+	sig->group_exit_task = NULL;
+	sig->notify_count = 0;
+
+no_thread_group:
+	/* we have changed execution domain */
+	tsk->exit_signal = SIGCHLD;
+
+	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;
+
+killed:
+	/* protects against exit_notify() and __exit_signal() */
+	read_lock(&tasklist_lock);
+	sig->group_exit_task = NULL;
+	sig->notify_count = 0;
+	read_unlock(&tasklist_lock);
+	return -EAGAIN;
+}
+
+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);
+
+/*
+ * These functions flushes out all traces of the currently running executable
+ * so that a new one can be started
+ */
+
+void __set_task_comm(struct task_struct *tsk, const char *buf, bool exec)
+{
+	task_lock(tsk);
+	trace_task_rename(tsk, buf);
+	strlcpy(tsk->comm, buf, sizeof(tsk->comm));
+	task_unlock(tsk);
+	perf_event_comm(tsk, exec);
+}
+
+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;
+
+	/*
+	 * Must be called _before_ exec_mmap() as bprm->mm is
+	 * not visibile until then. This also enables the update
+	 * to be lockless.
+	 */
+	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_FORKNOEXEC | PF_KTHREAD |
+					PF_NOFREEZE | PF_NO_SETAFFINITY);
+	flush_thread();
+	current->personality &= ~bprm->per_clear;
+
+	return 0;
+
+out:
+	return retval;
+}
+EXPORT_SYMBOL(flush_old_exec);
+
+void would_dump(struct linux_binprm *bprm, struct file *file)
+{
+	if (inode_permission(file_inode(file), MAY_READ) < 0)
+		bprm->interp_flags |= BINPRM_FLAGS_ENFORCE_NONDUMP;
+}
+EXPORT_SYMBOL(would_dump);
+
+void setup_new_exec(struct linux_binprm * bprm)
+{
+	arch_pick_mmap_layout(current->mm);
+
+	/* This is the point of no return */
+	current->sas_ss_sp = current->sas_ss_size = 0;
+
+	if (uid_eq(current_euid(), current_uid()) && gid_eq(current_egid(), current_gid()))
+		set_dumpable(current->mm, SUID_DUMP_USER);
+	else
+		set_dumpable(current->mm, suid_dumpable);
+
+	perf_event_exec();
+	__set_task_comm(current, kbasename(bprm->filename), true);
+
+	/* 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 (!uid_eq(bprm->cred->uid, current_euid()) ||
+	    !gid_eq(bprm->cred->gid, current_egid())) {
+		current->pdeath_signal = 0;
+	} else {
+		would_dump(bprm, bprm->file);
+		if (bprm->interp_flags & BINPRM_FLAGS_ENFORCE_NONDUMP)
+			set_dumpable(current->mm, suid_dumpable);
+	}
+
+	/* An exec changes our domain. We are no longer part of the thread
+	   group */
+	current->self_exec_id++;
+
+	flush_signal_handlers(current, 0);
+	do_close_on_exec(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;
+}
+
+static 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);
+	}
+	if (bprm->file) {
+		allow_write_access(bprm->file);
+		fput(bprm->file);
+	}
+	/* If a binfmt changed the interp, free it. */
+	if (bprm->interp != bprm->filename)
+		kfree(bprm->interp);
+	kfree(bprm);
+}
+
+int bprm_change_interp(char *interp, struct linux_binprm *bprm)
+{
+	/* If a binfmt changed the interp, free it first. */
+	if (bprm->interp != bprm->filename)
+		kfree(bprm->interp);
+	bprm->interp = kstrdup(interp, GFP_KERNEL);
+	if (!bprm->interp)
+		return -ENOMEM;
+	return 0;
+}
+EXPORT_SYMBOL(bprm_change_interp);
+
+/*
+ * 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;
+
+	/*
+	 * Disable monitoring for regular users
+	 * when executing setuid binaries. Must
+	 * wait until new credentials are committed
+	 * by commit_creds() above
+	 */
+	if (get_dumpable(current->mm) != SUID_DUMP_USER)
+		perf_event_exit_task(current);
+	/*
+	 * 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 or seccomp thread-sync
+ */
+static void check_unsafe_exec(struct linux_binprm *bprm)
+{
+	struct task_struct *p = current, *t;
+	unsigned n_fs;
+
+	if (p->ptrace) {
+		if (p->ptrace & PT_PTRACE_CAP)
+			bprm->unsafe |= LSM_UNSAFE_PTRACE_CAP;
+		else
+			bprm->unsafe |= LSM_UNSAFE_PTRACE;
+	}
+
+	/*
+	 * This isn't strictly necessary, but it makes it harder for LSMs to
+	 * mess up.
+	 */
+	if (task_no_new_privs(current))
+		bprm->unsafe |= LSM_UNSAFE_NO_NEW_PRIVS;
+
+	t = p;
+	n_fs = 1;
+	spin_lock(&p->fs->lock);
+	rcu_read_lock();
+	while_each_thread(p, t) {
+		if (t->fs == p->fs)
+			n_fs++;
+	}
+	rcu_read_unlock();
+
+	if (p->fs->users > n_fs)
+		bprm->unsafe |= LSM_UNSAFE_SHARE;
+	else
+		p->fs->in_exec = 1;
+	spin_unlock(&p->fs->lock);
+}
+
+static void bprm_fill_uid(struct linux_binprm *bprm)
+{
+	struct inode *inode;
+	unsigned int mode;
+	kuid_t uid;
+	kgid_t gid;
+
+	/* 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)
+		return;
+
+	if (task_no_new_privs(current))
+		return;
+
+	inode = file_inode(bprm->file);
+	mode = READ_ONCE(inode->i_mode);
+	if (!(mode & (S_ISUID|S_ISGID)))
+		return;
+
+	/* Be careful if suid/sgid is set */
+	mutex_lock(&inode->i_mutex);
+
+	/* reload atomically mode/uid/gid now that lock held */
+	mode = inode->i_mode;
+	uid = inode->i_uid;
+	gid = inode->i_gid;
+	mutex_unlock(&inode->i_mutex);
+
+	/* We ignore suid/sgid if there are no mappings for them in the ns */
+	if (!kuid_has_mapping(bprm->cred->user_ns, uid) ||
+		 !kgid_has_mapping(bprm->cred->user_ns, gid))
+		return;
+
+	if (mode & S_ISUID) {
+		bprm->per_clear |= PER_CLEAR_ON_SETID;
+		bprm->cred->euid = uid;
+	}
+
+	if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) {
+		bprm->per_clear |= PER_CLEAR_ON_SETID;
+		bprm->cred->egid = gid;
+	}
+}
+
+/*
+ * 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)
+{
+	int retval;
+
+	bprm_fill_uid(bprm);
+
+	/* 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);
+
+		for (; offset < PAGE_SIZE && kaddr[offset];
+				offset++, bprm->p++)
+			;
+
+		kunmap_atomic(kaddr);
+		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);
+
+#define printable(c) (((c)=='\t') || ((c)=='\n') || (0x20<=(c) && (c)<=0x7e))
+/*
+ * cycle the list of binary formats handler, until one recognizes the image
+ */
+int search_binary_handler(struct linux_binprm *bprm)
+{
+	bool need_retry = IS_ENABLED(CONFIG_MODULES);
+	struct linux_binfmt *fmt;
+	int retval;
+
+	/* This allows 4 levels of binfmt rewrites before failing hard. */
+	if (bprm->recursion_depth > 5)
+		return -ELOOP;
+
+	retval = security_bprm_check(bprm);
+	if (retval)
+		return retval;
+
+	retval = -ENOENT;
+ retry:
+	read_lock(&binfmt_lock);
+	list_for_each_entry(fmt, &formats, lh) {
+		if (!try_module_get(fmt->module))
+			continue;
+		read_unlock(&binfmt_lock);
+		bprm->recursion_depth++;
+		retval = fmt->load_binary(bprm);
+		read_lock(&binfmt_lock);
+		put_binfmt(fmt);
+		bprm->recursion_depth--;
+		if (retval < 0 && !bprm->mm) {
+			/* we got to flush_old_exec() and failed after it */
+			read_unlock(&binfmt_lock);
+			force_sigsegv(SIGSEGV, current);
+			return retval;
+		}
+		if (retval != -ENOEXEC || !bprm->file) {
+			read_unlock(&binfmt_lock);
+			return retval;
+		}
+	}
+	read_unlock(&binfmt_lock);
+
+	if (need_retry) {
+		if (printable(bprm->buf[0]) && printable(bprm->buf[1]) &&
+		    printable(bprm->buf[2]) && printable(bprm->buf[3]))
+			return retval;
+		if (request_module("binfmt-%04x", *(ushort *)(bprm->buf + 2)) < 0)
+			return retval;
+		need_retry = false;
+		goto retry;
+	}
+
+	return retval;
+}
+EXPORT_SYMBOL(search_binary_handler);
+
+static int exec_binprm(struct linux_binprm *bprm)
+{
+	pid_t old_pid, old_vpid;
+	int ret;
+
+	/* Need to fetch pid before load_binary changes it */
+	old_pid = current->pid;
+	rcu_read_lock();
+	old_vpid = task_pid_nr_ns(current, task_active_pid_ns(current->parent));
+	rcu_read_unlock();
+
+	ret = search_binary_handler(bprm);
+	if (ret >= 0) {
+		audit_bprm(bprm);
+		trace_sched_process_exec(current, old_pid, bprm);
+		ptrace_event(PTRACE_EVENT_EXEC, old_vpid);
+		proc_exec_connector(current);
+	}
+
+	return ret;
+}
+
+/*
+ * sys_execve() executes a new program.
+ */
+static int do_execveat_common(int fd, struct filename *filename,
+			      struct user_arg_ptr argv,
+			      struct user_arg_ptr envp,
+			      int flags)
+{
+	char *pathbuf = NULL;
+	struct linux_binprm *bprm;
+	struct file *file;
+	struct files_struct *displaced;
+	int retval;
+
+	if (IS_ERR(filename))
+		return PTR_ERR(filename);
+
+	/*
+	 * We move the actual failure in case of RLIMIT_NPROC excess from
+	 * set*uid() to execve() because too many poorly written programs
+	 * don't check setuid() return code.  Here we additionally recheck
+	 * whether NPROC limit is still exceeded.
+	 */
+	if ((current->flags & PF_NPROC_EXCEEDED) &&
+	    atomic_read(&current_user()->processes) > rlimit(RLIMIT_NPROC)) {
+		retval = -EAGAIN;
+		goto out_ret;
+	}
+
+	/* We're below the limit (still or again), so we don't want to make
+	 * further execve() calls fail. */
+	current->flags &= ~PF_NPROC_EXCEEDED;
+
+	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;
+
+	check_unsafe_exec(bprm);
+	current->in_execve = 1;
+
+	file = do_open_execat(fd, filename, flags);
+	retval = PTR_ERR(file);
+	if (IS_ERR(file))
+		goto out_unmark;
+
+	sched_exec();
+
+	bprm->file = file;
+	if (fd == AT_FDCWD || filename->name[0] == '/') {
+		bprm->filename = filename->name;
+	} else {
+		if (filename->name[0] == '\0')
+			pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d", fd);
+		else
+			pathbuf = kasprintf(GFP_TEMPORARY, "/dev/fd/%d/%s",
+					    fd, filename->name);
+		if (!pathbuf) {
+			retval = -ENOMEM;
+			goto out_unmark;
+		}
+		/*
+		 * Record that a name derived from an O_CLOEXEC fd will be
+		 * inaccessible after exec. Relies on having exclusive access to
+		 * current->files (due to unshare_files above).
+		 */
+		if (close_on_exec(fd, rcu_dereference_raw(current->files->fdt)))
+			bprm->interp_flags |= BINPRM_FLAGS_PATH_INACCESSIBLE;
+		bprm->filename = pathbuf;
+	}
+	bprm->interp = bprm->filename;
+
+	retval = bprm_mm_init(bprm);
+	if (retval)
+		goto out_unmark;
+
+	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 = exec_binprm(bprm);
+	if (retval < 0)
+		goto out;
+
+	/* execve succeeded */
+	current->fs->in_exec = 0;
+	current->in_execve = 0;
+	acct_update_integrals(current);
+	task_numa_free(current);
+	free_bprm(bprm);
+	kfree(pathbuf);
+	putname(filename);
+	if (displaced)
+		put_files_struct(displaced);
+	return retval;
+
+out:
+	if (bprm->mm) {
+		acct_arg_size(bprm, 0);
+		mmput(bprm->mm);
+	}
+
+out_unmark:
+	current->fs->in_exec = 0;
+	current->in_execve = 0;
+
+out_free:
+	free_bprm(bprm);
+	kfree(pathbuf);
+
+out_files:
+	if (displaced)
+		reset_files_struct(displaced);
+out_ret:
+	putname(filename);
+	return retval;
+}
+
+int do_execve(struct filename *filename,
+	const char __user *const __user *__argv,
+	const char __user *const __user *__envp)
+{
+	struct user_arg_ptr argv = { .ptr.native = __argv };
+	struct user_arg_ptr envp = { .ptr.native = __envp };
+	return do_execveat_common(AT_FDCWD, filename, argv, envp, 0);
+}
+
+int do_execveat(int fd, struct filename *filename,
+		const char __user *const __user *__argv,
+		const char __user *const __user *__envp,
+		int flags)
+{
+	struct user_arg_ptr argv = { .ptr.native = __argv };
+	struct user_arg_ptr envp = { .ptr.native = __envp };
+
+	return do_execveat_common(fd, filename, argv, envp, flags);
+}
+
+#ifdef CONFIG_COMPAT
+static int compat_do_execve(struct filename *filename,
+	const compat_uptr_t __user *__argv,
+	const compat_uptr_t __user *__envp)
+{
+	struct user_arg_ptr argv = {
+		.is_compat = true,
+		.ptr.compat = __argv,
+	};
+	struct user_arg_ptr envp = {
+		.is_compat = true,
+		.ptr.compat = __envp,
+	};
+	return do_execveat_common(AT_FDCWD, filename, argv, envp, 0);
+}
+
+static int compat_do_execveat(int fd, struct filename *filename,
+			      const compat_uptr_t __user *__argv,
+			      const compat_uptr_t __user *__envp,
+			      int flags)
+{
+	struct user_arg_ptr argv = {
+		.is_compat = true,
+		.ptr.compat = __argv,
+	};
+	struct user_arg_ptr envp = {
+		.is_compat = true,
+		.ptr.compat = __envp,
+	};
+	return do_execveat_common(fd, filename, argv, envp, flags);
+}
+#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);
+
+/*
+ * set_dumpable stores three-value SUID_DUMP_* into mm->flags.
+ */
+void set_dumpable(struct mm_struct *mm, int value)
+{
+	unsigned long old, new;
+
+	if (WARN_ON((unsigned)value > SUID_DUMP_ROOT))
+		return;
+
+	do {
+		old = ACCESS_ONCE(mm->flags);
+		new = (old & ~MMF_DUMPABLE_MASK) | value;
+	} while (cmpxchg(&mm->flags, old, new) != old);
+}
+
+SYSCALL_DEFINE3(execve,
+		const char __user *, filename,
+		const char __user *const __user *, argv,
+		const char __user *const __user *, envp)
+{
+	return do_execve(getname(filename), argv, envp);
+}
+
+SYSCALL_DEFINE5(execveat,
+		int, fd, const char __user *, filename,
+		const char __user *const __user *, argv,
+		const char __user *const __user *, envp,
+		int, flags)
+{
+	int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0;
+
+	return do_execveat(fd,
+			   getname_flags(filename, lookup_flags, NULL),
+			   argv, envp, flags);
+}
+
+#ifdef CONFIG_COMPAT
+COMPAT_SYSCALL_DEFINE3(execve, const char __user *, filename,
+	const compat_uptr_t __user *, argv,
+	const compat_uptr_t __user *, envp)
+{
+	return compat_do_execve(getname(filename), argv, envp);
+}
+
+COMPAT_SYSCALL_DEFINE5(execveat, int, fd,
+		       const char __user *, filename,
+		       const compat_uptr_t __user *, argv,
+		       const compat_uptr_t __user *, envp,
+		       int,  flags)
+{
+	int lookup_flags = (flags & AT_EMPTY_PATH) ? LOOKUP_EMPTY : 0;
+
+	return compat_do_execveat(fd,
+				  getname_flags(filename, lookup_flags, NULL),
+				  argv, envp, flags);
+}
+#endif