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Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license as published by the free software foundation either version 2 of the license or at your option any later version extracted by the scancode license scanner the SPDX license identifier GPL-2.0-or-later has been chosen to replace the boilerplate/reference in 3029 file(s). Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Allison Randal <allison@lohutok.net> Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
372 lines
9.8 KiB
C
372 lines
9.8 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* linux/mm/process_vm_access.c
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*
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* Copyright (C) 2010-2011 Christopher Yeoh <cyeoh@au1.ibm.com>, IBM Corp.
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*/
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#include <linux/mm.h>
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#include <linux/uio.h>
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#include <linux/sched.h>
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#include <linux/sched/mm.h>
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#include <linux/highmem.h>
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#include <linux/ptrace.h>
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#include <linux/slab.h>
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#include <linux/syscalls.h>
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#ifdef CONFIG_COMPAT
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#include <linux/compat.h>
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#endif
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/**
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* process_vm_rw_pages - read/write pages from task specified
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* @pages: array of pointers to pages we want to copy
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* @offset: offset in page to start copying from/to
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* @len: number of bytes to copy
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* @iter: where to copy to/from locally
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* @vm_write: 0 means copy from, 1 means copy to
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* Returns 0 on success, error code otherwise
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*/
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static int process_vm_rw_pages(struct page **pages,
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unsigned offset,
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size_t len,
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struct iov_iter *iter,
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int vm_write)
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{
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/* Do the copy for each page */
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while (len && iov_iter_count(iter)) {
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struct page *page = *pages++;
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size_t copy = PAGE_SIZE - offset;
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size_t copied;
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if (copy > len)
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copy = len;
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if (vm_write) {
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copied = copy_page_from_iter(page, offset, copy, iter);
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set_page_dirty_lock(page);
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} else {
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copied = copy_page_to_iter(page, offset, copy, iter);
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}
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len -= copied;
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if (copied < copy && iov_iter_count(iter))
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return -EFAULT;
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offset = 0;
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}
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return 0;
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}
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/* Maximum number of pages kmalloc'd to hold struct page's during copy */
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#define PVM_MAX_KMALLOC_PAGES (PAGE_SIZE * 2)
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/**
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* process_vm_rw_single_vec - read/write pages from task specified
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* @addr: start memory address of target process
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* @len: size of area to copy to/from
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* @iter: where to copy to/from locally
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* @process_pages: struct pages area that can store at least
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* nr_pages_to_copy struct page pointers
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* @mm: mm for task
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* @task: task to read/write from
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* @vm_write: 0 means copy from, 1 means copy to
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* Returns 0 on success or on failure error code
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*/
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static int process_vm_rw_single_vec(unsigned long addr,
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unsigned long len,
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struct iov_iter *iter,
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struct page **process_pages,
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struct mm_struct *mm,
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struct task_struct *task,
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int vm_write)
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{
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unsigned long pa = addr & PAGE_MASK;
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unsigned long start_offset = addr - pa;
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unsigned long nr_pages;
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ssize_t rc = 0;
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unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
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/ sizeof(struct pages *);
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unsigned int flags = 0;
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/* Work out address and page range required */
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if (len == 0)
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return 0;
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nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;
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if (vm_write)
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flags |= FOLL_WRITE;
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while (!rc && nr_pages && iov_iter_count(iter)) {
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int pages = min(nr_pages, max_pages_per_loop);
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int locked = 1;
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size_t bytes;
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/*
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* Get the pages we're interested in. We must
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* access remotely because task/mm might not
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* current/current->mm
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*/
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down_read(&mm->mmap_sem);
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pages = get_user_pages_remote(task, mm, pa, pages, flags,
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process_pages, NULL, &locked);
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if (locked)
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up_read(&mm->mmap_sem);
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if (pages <= 0)
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return -EFAULT;
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bytes = pages * PAGE_SIZE - start_offset;
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if (bytes > len)
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bytes = len;
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rc = process_vm_rw_pages(process_pages,
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start_offset, bytes, iter,
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vm_write);
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len -= bytes;
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start_offset = 0;
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nr_pages -= pages;
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pa += pages * PAGE_SIZE;
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while (pages)
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put_page(process_pages[--pages]);
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}
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return rc;
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}
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/* Maximum number of entries for process pages array
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which lives on stack */
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#define PVM_MAX_PP_ARRAY_COUNT 16
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/**
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* process_vm_rw_core - core of reading/writing pages from task specified
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* @pid: PID of process to read/write from/to
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* @iter: where to copy to/from locally
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* @rvec: iovec array specifying where to copy to/from in the other process
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* @riovcnt: size of rvec array
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* @flags: currently unused
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* @vm_write: 0 if reading from other process, 1 if writing to other process
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*
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* Returns the number of bytes read/written or error code. May
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* return less bytes than expected if an error occurs during the copying
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* process.
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*/
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static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
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const struct iovec *rvec,
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unsigned long riovcnt,
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unsigned long flags, int vm_write)
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{
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struct task_struct *task;
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struct page *pp_stack[PVM_MAX_PP_ARRAY_COUNT];
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struct page **process_pages = pp_stack;
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struct mm_struct *mm;
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unsigned long i;
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ssize_t rc = 0;
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unsigned long nr_pages = 0;
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unsigned long nr_pages_iov;
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ssize_t iov_len;
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size_t total_len = iov_iter_count(iter);
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/*
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* Work out how many pages of struct pages we're going to need
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* when eventually calling get_user_pages
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*/
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for (i = 0; i < riovcnt; i++) {
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iov_len = rvec[i].iov_len;
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if (iov_len > 0) {
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nr_pages_iov = ((unsigned long)rvec[i].iov_base
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+ iov_len)
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/ PAGE_SIZE - (unsigned long)rvec[i].iov_base
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/ PAGE_SIZE + 1;
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nr_pages = max(nr_pages, nr_pages_iov);
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}
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}
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if (nr_pages == 0)
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return 0;
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if (nr_pages > PVM_MAX_PP_ARRAY_COUNT) {
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/* For reliability don't try to kmalloc more than
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2 pages worth */
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process_pages = kmalloc(min_t(size_t, PVM_MAX_KMALLOC_PAGES,
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sizeof(struct pages *)*nr_pages),
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GFP_KERNEL);
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if (!process_pages)
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return -ENOMEM;
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}
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/* Get process information */
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task = find_get_task_by_vpid(pid);
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if (!task) {
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rc = -ESRCH;
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goto free_proc_pages;
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}
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mm = mm_access(task, PTRACE_MODE_ATTACH_REALCREDS);
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if (!mm || IS_ERR(mm)) {
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rc = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
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/*
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* Explicitly map EACCES to EPERM as EPERM is a more a
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* appropriate error code for process_vw_readv/writev
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*/
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if (rc == -EACCES)
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rc = -EPERM;
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goto put_task_struct;
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}
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for (i = 0; i < riovcnt && iov_iter_count(iter) && !rc; i++)
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rc = process_vm_rw_single_vec(
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(unsigned long)rvec[i].iov_base, rvec[i].iov_len,
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iter, process_pages, mm, task, vm_write);
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/* copied = space before - space after */
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total_len -= iov_iter_count(iter);
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/* If we have managed to copy any data at all then
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we return the number of bytes copied. Otherwise
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we return the error code */
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if (total_len)
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rc = total_len;
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mmput(mm);
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put_task_struct:
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put_task_struct(task);
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free_proc_pages:
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if (process_pages != pp_stack)
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kfree(process_pages);
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return rc;
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}
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/**
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* process_vm_rw - check iovecs before calling core routine
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* @pid: PID of process to read/write from/to
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* @lvec: iovec array specifying where to copy to/from locally
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* @liovcnt: size of lvec array
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* @rvec: iovec array specifying where to copy to/from in the other process
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* @riovcnt: size of rvec array
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* @flags: currently unused
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* @vm_write: 0 if reading from other process, 1 if writing to other process
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*
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* Returns the number of bytes read/written or error code. May
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* return less bytes than expected if an error occurs during the copying
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* process.
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*/
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static ssize_t process_vm_rw(pid_t pid,
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const struct iovec __user *lvec,
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unsigned long liovcnt,
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const struct iovec __user *rvec,
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unsigned long riovcnt,
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unsigned long flags, int vm_write)
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{
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struct iovec iovstack_l[UIO_FASTIOV];
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struct iovec iovstack_r[UIO_FASTIOV];
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struct iovec *iov_l = iovstack_l;
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struct iovec *iov_r = iovstack_r;
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struct iov_iter iter;
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ssize_t rc;
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int dir = vm_write ? WRITE : READ;
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if (flags != 0)
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return -EINVAL;
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/* Check iovecs */
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rc = import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter);
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if (rc < 0)
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return rc;
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if (!iov_iter_count(&iter))
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goto free_iovecs;
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rc = rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV,
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iovstack_r, &iov_r);
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if (rc <= 0)
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goto free_iovecs;
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rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);
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free_iovecs:
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if (iov_r != iovstack_r)
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kfree(iov_r);
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kfree(iov_l);
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return rc;
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}
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SYSCALL_DEFINE6(process_vm_readv, pid_t, pid, const struct iovec __user *, lvec,
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unsigned long, liovcnt, const struct iovec __user *, rvec,
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unsigned long, riovcnt, unsigned long, flags)
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{
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return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 0);
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}
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SYSCALL_DEFINE6(process_vm_writev, pid_t, pid,
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const struct iovec __user *, lvec,
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unsigned long, liovcnt, const struct iovec __user *, rvec,
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unsigned long, riovcnt, unsigned long, flags)
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{
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return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 1);
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}
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#ifdef CONFIG_COMPAT
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static ssize_t
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compat_process_vm_rw(compat_pid_t pid,
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const struct compat_iovec __user *lvec,
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unsigned long liovcnt,
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const struct compat_iovec __user *rvec,
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unsigned long riovcnt,
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unsigned long flags, int vm_write)
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{
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struct iovec iovstack_l[UIO_FASTIOV];
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struct iovec iovstack_r[UIO_FASTIOV];
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struct iovec *iov_l = iovstack_l;
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struct iovec *iov_r = iovstack_r;
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struct iov_iter iter;
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ssize_t rc = -EFAULT;
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int dir = vm_write ? WRITE : READ;
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if (flags != 0)
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return -EINVAL;
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rc = compat_import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter);
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if (rc < 0)
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return rc;
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if (!iov_iter_count(&iter))
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goto free_iovecs;
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rc = compat_rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt,
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UIO_FASTIOV, iovstack_r,
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&iov_r);
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if (rc <= 0)
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goto free_iovecs;
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rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);
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free_iovecs:
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if (iov_r != iovstack_r)
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kfree(iov_r);
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kfree(iov_l);
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return rc;
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}
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COMPAT_SYSCALL_DEFINE6(process_vm_readv, compat_pid_t, pid,
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const struct compat_iovec __user *, lvec,
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compat_ulong_t, liovcnt,
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const struct compat_iovec __user *, rvec,
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compat_ulong_t, riovcnt,
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compat_ulong_t, flags)
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{
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return compat_process_vm_rw(pid, lvec, liovcnt, rvec,
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riovcnt, flags, 0);
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}
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COMPAT_SYSCALL_DEFINE6(process_vm_writev, compat_pid_t, pid,
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const struct compat_iovec __user *, lvec,
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compat_ulong_t, liovcnt,
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const struct compat_iovec __user *, rvec,
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compat_ulong_t, riovcnt,
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compat_ulong_t, flags)
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{
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return compat_process_vm_rw(pid, lvec, liovcnt, rvec,
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riovcnt, flags, 1);
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}
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#endif
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