1642 lines
38 KiB
C
Executable File
1642 lines
38 KiB
C
Executable File
/*
|
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* linux/fs/exec.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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/*
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* #!-checking implemented by tytso.
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*/
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/*
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* Demand-loading implemented 01.12.91 - no need to read anything but
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* the header into memory. The inode of the executable is put into
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* "current->executable", and page faults do the actual loading. Clean.
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*
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* Once more I can proudly say that linux stood up to being changed: it
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* was less than 2 hours work to get demand-loading completely implemented.
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*
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* Demand loading changed July 1993 by Eric Youngdale. Use mmap instead,
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* current->executable is only used by the procfs. This allows a dispatch
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* table to check for several different types of binary formats. We keep
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* trying until we recognize the file or we run out of supported binary
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* formats.
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*/
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#include <linux/slab.h>
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#include <linux/file.h>
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#include <linux/fdtable.h>
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#include <linux/mm.h>
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#include <linux/vmacache.h>
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#include <linux/stat.h>
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#include <linux/fcntl.h>
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#include <linux/swap.h>
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#include <linux/string.h>
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#include <linux/init.h>
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#include <linux/pagemap.h>
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#include <linux/perf_event.h>
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#include <linux/highmem.h>
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#include <linux/spinlock.h>
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#include <linux/key.h>
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#include <linux/personality.h>
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#include <linux/binfmts.h>
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#include <linux/utsname.h>
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#include <linux/pid_namespace.h>
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#include <linux/module.h>
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#include <linux/namei.h>
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#include <linux/mount.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/tsacct_kern.h>
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#include <linux/cn_proc.h>
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#include <linux/audit.h>
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#include <linux/tracehook.h>
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#include <linux/kmod.h>
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#include <linux/fsnotify.h>
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#include <linux/fs_struct.h>
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#include <linux/pipe_fs_i.h>
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#include <linux/oom.h>
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#include <linux/compat.h>
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#include <asm/uaccess.h>
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#include <asm/mmu_context.h>
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#include <asm/tlb.h>
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#include <trace/events/task.h>
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#include "internal.h"
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#include <trace/events/sched.h>
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int suid_dumpable = 0;
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static LIST_HEAD(formats);
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static DEFINE_RWLOCK(binfmt_lock);
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void __register_binfmt(struct linux_binfmt * fmt, int insert)
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{
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BUG_ON(!fmt);
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if (WARN_ON(!fmt->load_binary))
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return;
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write_lock(&binfmt_lock);
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insert ? list_add(&fmt->lh, &formats) :
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list_add_tail(&fmt->lh, &formats);
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write_unlock(&binfmt_lock);
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}
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EXPORT_SYMBOL(__register_binfmt);
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void unregister_binfmt(struct linux_binfmt * fmt)
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{
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write_lock(&binfmt_lock);
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list_del(&fmt->lh);
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write_unlock(&binfmt_lock);
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}
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EXPORT_SYMBOL(unregister_binfmt);
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static inline void put_binfmt(struct linux_binfmt * fmt)
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{
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module_put(fmt->module);
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}
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#ifdef CONFIG_USELIB
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/*
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* Note that a shared library must be both readable and executable due to
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* security reasons.
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*
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* Also note that we take the address to load from from the file itself.
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*/
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SYSCALL_DEFINE1(uselib, const char __user *, library)
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{
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struct linux_binfmt *fmt;
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struct file *file;
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struct filename *tmp = getname(library);
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int error = PTR_ERR(tmp);
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static const struct open_flags uselib_flags = {
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.open_flag = O_LARGEFILE | O_RDONLY | __FMODE_EXEC,
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.acc_mode = MAY_READ | MAY_EXEC | MAY_OPEN,
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.intent = LOOKUP_OPEN,
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.lookup_flags = LOOKUP_FOLLOW,
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};
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if (IS_ERR(tmp))
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goto out;
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file = do_filp_open(AT_FDCWD, tmp, &uselib_flags);
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putname(tmp);
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error = PTR_ERR(file);
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if (IS_ERR(file))
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goto out;
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error = -EINVAL;
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if (!S_ISREG(file_inode(file)->i_mode))
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goto exit;
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error = -EACCES;
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if (file->f_path.mnt->mnt_flags & MNT_NOEXEC)
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goto exit;
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fsnotify_open(file);
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error = -ENOEXEC;
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read_lock(&binfmt_lock);
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list_for_each_entry(fmt, &formats, lh) {
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if (!fmt->load_shlib)
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continue;
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if (!try_module_get(fmt->module))
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continue;
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read_unlock(&binfmt_lock);
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error = fmt->load_shlib(file);
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read_lock(&binfmt_lock);
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put_binfmt(fmt);
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if (error != -ENOEXEC)
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break;
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}
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read_unlock(&binfmt_lock);
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exit:
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fput(file);
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out:
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return error;
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}
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#endif /* #ifdef CONFIG_USELIB */
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#ifdef CONFIG_MMU
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/*
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* The nascent bprm->mm is not visible until exec_mmap() but it can
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* use a lot of memory, account these pages in current->mm temporary
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* for oom_badness()->get_mm_rss(). Once exec succeeds or fails, we
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* change the counter back via acct_arg_size(0).
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*/
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static void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
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{
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struct mm_struct *mm = current->mm;
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long diff = (long)(pages - bprm->vma_pages);
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if (!mm || !diff)
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return;
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bprm->vma_pages = pages;
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add_mm_counter(mm, MM_ANONPAGES, diff);
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}
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static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
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int write)
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{
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struct page *page;
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int ret;
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#ifdef CONFIG_STACK_GROWSUP
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if (write) {
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ret = expand_downwards(bprm->vma, pos);
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if (ret < 0)
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return NULL;
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}
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#endif
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ret = get_user_pages(current, bprm->mm, pos,
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1, write, 1, &page, NULL);
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if (ret <= 0)
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return NULL;
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if (write) {
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unsigned long size = bprm->vma->vm_end - bprm->vma->vm_start;
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struct rlimit *rlim;
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acct_arg_size(bprm, size / PAGE_SIZE);
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/*
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* We've historically supported up to 32 pages (ARG_MAX)
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* of argument strings even with small stacks
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*/
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if (size <= ARG_MAX)
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return page;
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/*
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* Limit to 1/4-th the stack size for the argv+env strings.
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* This ensures that:
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* - the remaining binfmt code will not run out of stack space,
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* - the program will have a reasonable amount of stack left
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* to work from.
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*/
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rlim = current->signal->rlim;
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if (size > ACCESS_ONCE(rlim[RLIMIT_STACK].rlim_cur) / 4) {
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put_page(page);
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return NULL;
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}
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}
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return page;
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}
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static void put_arg_page(struct page *page)
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{
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put_page(page);
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}
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static void free_arg_page(struct linux_binprm *bprm, int i)
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{
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}
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static void free_arg_pages(struct linux_binprm *bprm)
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{
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}
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static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
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struct page *page)
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{
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flush_cache_page(bprm->vma, pos, page_to_pfn(page));
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}
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static int __bprm_mm_init(struct linux_binprm *bprm)
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{
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int err;
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struct vm_area_struct *vma = NULL;
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struct mm_struct *mm = bprm->mm;
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bprm->vma = vma = kmem_cache_zalloc(vm_area_cachep, GFP_KERNEL);
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if (!vma)
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return -ENOMEM;
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down_write(&mm->mmap_sem);
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vma->vm_mm = mm;
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/*
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* Place the stack at the largest stack address the architecture
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* supports. Later, we'll move this to an appropriate place. We don't
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* use STACK_TOP because that can depend on attributes which aren't
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* configured yet.
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*/
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BUILD_BUG_ON(VM_STACK_FLAGS & VM_STACK_INCOMPLETE_SETUP);
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vma->vm_end = STACK_TOP_MAX;
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vma->vm_start = vma->vm_end - PAGE_SIZE;
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vma->vm_flags = VM_SOFTDIRTY | VM_STACK_FLAGS | VM_STACK_INCOMPLETE_SETUP;
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vma->vm_page_prot = vm_get_page_prot(vma->vm_flags);
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INIT_LIST_HEAD(&vma->anon_vma_chain);
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err = insert_vm_struct(mm, vma);
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if (err)
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goto err;
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mm->stack_vm = mm->total_vm = 1;
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up_write(&mm->mmap_sem);
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bprm->p = vma->vm_end - sizeof(void *);
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return 0;
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err:
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up_write(&mm->mmap_sem);
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bprm->vma = NULL;
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kmem_cache_free(vm_area_cachep, vma);
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return err;
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}
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static bool valid_arg_len(struct linux_binprm *bprm, long len)
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{
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return len <= MAX_ARG_STRLEN;
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}
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#else
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static inline void acct_arg_size(struct linux_binprm *bprm, unsigned long pages)
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{
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}
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static struct page *get_arg_page(struct linux_binprm *bprm, unsigned long pos,
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int write)
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{
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struct page *page;
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page = bprm->page[pos / PAGE_SIZE];
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if (!page && write) {
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page = alloc_page(GFP_HIGHUSER|__GFP_ZERO);
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if (!page)
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return NULL;
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bprm->page[pos / PAGE_SIZE] = page;
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}
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return page;
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}
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static void put_arg_page(struct page *page)
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{
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}
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static void free_arg_page(struct linux_binprm *bprm, int i)
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{
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if (bprm->page[i]) {
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__free_page(bprm->page[i]);
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bprm->page[i] = NULL;
|
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}
|
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}
|
|
|
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static void free_arg_pages(struct linux_binprm *bprm)
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{
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|
int i;
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|
|
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for (i = 0; i < MAX_ARG_PAGES; i++)
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free_arg_page(bprm, i);
|
|
}
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|
|
static void flush_arg_page(struct linux_binprm *bprm, unsigned long pos,
|
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struct page *page)
|
|
{
|
|
}
|
|
|
|
static int __bprm_mm_init(struct linux_binprm *bprm)
|
|
{
|
|
bprm->p = PAGE_SIZE * MAX_ARG_PAGES - sizeof(void *);
|
|
return 0;
|
|
}
|
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|
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static bool valid_arg_len(struct linux_binprm *bprm, long len)
|
|
{
|
|
return len <= bprm->p;
|
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}
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#endif /* CONFIG_MMU */
|
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|
|
/*
|
|
* 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_exec(struct filename *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,
|
|
.lookup_flags = LOOKUP_FOLLOW,
|
|
};
|
|
|
|
file = do_filp_open(AT_FDCWD, 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;
|
|
|
|
fsnotify_open(file);
|
|
|
|
err = deny_write_access(file);
|
|
if (err)
|
|
goto exit;
|
|
|
|
out:
|
|
return file;
|
|
|
|
exit:
|
|
fput(file);
|
|
return ERR_PTR(err);
|
|
}
|
|
|
|
struct file *open_exec(const char *name)
|
|
{
|
|
struct filename tmp = { .name = name };
|
|
return do_open_exec(&tmp);
|
|
}
|
|
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;
|
|
|
|
sig->notify_count = -1; /* for exit_notify() */
|
|
for (;;) {
|
|
threadgroup_change_begin(tsk);
|
|
write_lock_irq(&tasklist_lock);
|
|
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;
|
|
|
|
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(¤t->signal->cred_guard_mutex))
|
|
return -ERESTARTNOINTR;
|
|
|
|
bprm->cred = prepare_exec_creds();
|
|
if (likely(bprm->cred))
|
|
return 0;
|
|
|
|
mutex_unlock(¤t->signal->cred_guard_mutex);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
static void free_bprm(struct linux_binprm *bprm)
|
|
{
|
|
free_arg_pages(bprm);
|
|
if (bprm->cred) {
|
|
mutex_unlock(¤t->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(¤t->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_execve_common(struct filename *filename,
|
|
struct user_arg_ptr argv,
|
|
struct user_arg_ptr envp)
|
|
{
|
|
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(¤t_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_exec(filename);
|
|
retval = PTR_ERR(file);
|
|
if (IS_ERR(file))
|
|
goto out_unmark;
|
|
|
|
sched_exec();
|
|
|
|
bprm->file = file;
|
|
bprm->filename = bprm->interp = filename->name;
|
|
|
|
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);
|
|
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);
|
|
|
|
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_execve_common(filename, argv, envp);
|
|
}
|
|
|
|
#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_execve_common(filename, argv, envp);
|
|
}
|
|
#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);
|
|
}
|
|
#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);
|
|
}
|
|
#endif
|