[linux.git] / mm / process_vm_access.c

/*
 * linux/mm/process_vm_access.c
 *
 * Copyright (C) 2010-2011 Christopher Yeoh <[email protected]>, IBM Corp.
 *
 * 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.
 */

#include <linux/mm.h>
#include <linux/uio.h>
#include <linux/sched.h>
#include <linux/sched/mm.h>
#include <linux/highmem.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/syscalls.h>

#ifdef CONFIG_COMPAT
#include <linux/compat.h>
#endif

/**
 * process_vm_rw_pages - read/write pages from task specified
 * @pages: array of pointers to pages we want to copy
 * @start_offset: offset in page to start copying from/to
 * @len: number of bytes to copy
 * @iter: where to copy to/from locally
 * @vm_write: 0 means copy from, 1 means copy to
 * Returns 0 on success, error code otherwise
 */
static int process_vm_rw_pages(struct page **pages,
			       unsigned offset,
			       size_t len,
			       struct iov_iter *iter,
			       int vm_write)
{
	/* Do the copy for each page */
	while (len && iov_iter_count(iter)) {
		struct page *page = *pages++;
		size_t copy = PAGE_SIZE - offset;
		size_t copied;

		if (copy > len)
			copy = len;

		if (vm_write) {
			copied = copy_page_from_iter(page, offset, copy, iter);
			set_page_dirty_lock(page);
		} else {
			copied = copy_page_to_iter(page, offset, copy, iter);
		}
		len -= copied;
		if (copied < copy && iov_iter_count(iter))
			return -EFAULT;
		offset = 0;
	}
	return 0;
}

/* Maximum number of pages kmalloc'd to hold struct page's during copy */
#define PVM_MAX_KMALLOC_PAGES (PAGE_SIZE * 2)

/**
 * process_vm_rw_single_vec - read/write pages from task specified
 * @addr: start memory address of target process
 * @len: size of area to copy to/from
 * @iter: where to copy to/from locally
 * @process_pages: struct pages area that can store at least
 *  nr_pages_to_copy struct page pointers
 * @mm: mm for task
 * @task: task to read/write from
 * @vm_write: 0 means copy from, 1 means copy to
 * Returns 0 on success or on failure error code
 */
static int process_vm_rw_single_vec(unsigned long addr,
				    unsigned long len,
				    struct iov_iter *iter,
				    struct page **process_pages,
				    struct mm_struct *mm,
				    struct task_struct *task,
				    int vm_write)
{
	unsigned long pa = addr & PAGE_MASK;
	unsigned long start_offset = addr - pa;
	unsigned long nr_pages;
	ssize_t rc = 0;
	unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
		/ sizeof(struct pages *);
	unsigned int flags = 0;

	/* Work out address and page range required */
	if (len == 0)
		return 0;
	nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;

	if (vm_write)
		flags |= FOLL_WRITE;

	while (!rc && nr_pages && iov_iter_count(iter)) {
		int pages = min(nr_pages, max_pages_per_loop);
		int locked = 1;
		size_t bytes;

		/*
		 * Get the pages we're interested in.  We must
		 * access remotely because task/mm might not
		 * current/current->mm
		 */
		down_read(&mm->mmap_sem);
		pages = get_user_pages_remote(task, mm, pa, pages, flags,
					      process_pages, NULL, &locked);
		if (locked)
			up_read(&mm->mmap_sem);
		if (pages <= 0)
			return -EFAULT;

		bytes = pages * PAGE_SIZE - start_offset;
		if (bytes > len)
			bytes = len;

		rc = process_vm_rw_pages(process_pages,
					 start_offset, bytes, iter,
					 vm_write);
		len -= bytes;
		start_offset = 0;
		nr_pages -= pages;
		pa += pages * PAGE_SIZE;
		while (pages)
			put_page(process_pages[--pages]);
	}

	return rc;
}

/* Maximum number of entries for process pages array
   which lives on stack */
#define PVM_MAX_PP_ARRAY_COUNT 16

/**
 * process_vm_rw_core - core of reading/writing pages from task specified
 * @pid: PID of process to read/write from/to
 * @iter: where to copy to/from locally
 * @rvec: iovec array specifying where to copy to/from in the other process
 * @riovcnt: size of rvec array
 * @flags: currently unused
 * @vm_write: 0 if reading from other process, 1 if writing to other process
 * Returns the number of bytes read/written or error code. May
 *  return less bytes than expected if an error occurs during the copying
 *  process.
 */
static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
				  const struct iovec *rvec,
				  unsigned long riovcnt,
				  unsigned long flags, int vm_write)
{
	struct task_struct *task;
	struct page *pp_stack[PVM_MAX_PP_ARRAY_COUNT];
	struct page **process_pages = pp_stack;
	struct mm_struct *mm;
	unsigned long i;
	ssize_t rc = 0;
	unsigned long nr_pages = 0;
	unsigned long nr_pages_iov;
	ssize_t iov_len;
	size_t total_len = iov_iter_count(iter);

	/*
	 * Work out how many pages of struct pages we're going to need
	 * when eventually calling get_user_pages
	 */
	for (i = 0; i < riovcnt; i++) {
		iov_len = rvec[i].iov_len;
		if (iov_len > 0) {
			nr_pages_iov = ((unsigned long)rvec[i].iov_base
					+ iov_len)
				/ PAGE_SIZE - (unsigned long)rvec[i].iov_base
				/ PAGE_SIZE + 1;
			nr_pages = max(nr_pages, nr_pages_iov);
		}
	}

	if (nr_pages == 0)
		return 0;

	if (nr_pages > PVM_MAX_PP_ARRAY_COUNT) {
		/* For reliability don't try to kmalloc more than
		   2 pages worth */
		process_pages = kmalloc(min_t(size_t, PVM_MAX_KMALLOC_PAGES,
					      sizeof(struct pages *)*nr_pages),
					GFP_KERNEL);

		if (!process_pages)
			return -ENOMEM;
	}

	/* Get process information */
	rcu_read_lock();
	task = find_task_by_vpid(pid);
	if (task)
		get_task_struct(task);
	rcu_read_unlock();
	if (!task) {
		rc = -ESRCH;
		goto free_proc_pages;
	}

	mm = mm_access(task, PTRACE_MODE_ATTACH_REALCREDS);
	if (!mm || IS_ERR(mm)) {
		rc = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
		/*
		 * Explicitly map EACCES to EPERM as EPERM is a more a
		 * appropriate error code for process_vw_readv/writev
		 */
		if (rc == -EACCES)
			rc = -EPERM;
		goto put_task_struct;
	}

	for (i = 0; i < riovcnt && iov_iter_count(iter) && !rc; i++)
		rc = process_vm_rw_single_vec(
			(unsigned long)rvec[i].iov_base, rvec[i].iov_len,
			iter, process_pages, mm, task, vm_write);

	/* copied = space before - space after */
	total_len -= iov_iter_count(iter);

	/* If we have managed to copy any data at all then
	   we return the number of bytes copied. Otherwise
	   we return the error code */
	if (total_len)
		rc = total_len;

	mmput(mm);

put_task_struct:
	put_task_struct(task);

free_proc_pages:
	if (process_pages != pp_stack)
		kfree(process_pages);
	return rc;
}

/**
 * process_vm_rw - check iovecs before calling core routine
 * @pid: PID of process to read/write from/to
 * @lvec: iovec array specifying where to copy to/from locally
 * @liovcnt: size of lvec array
 * @rvec: iovec array specifying where to copy to/from in the other process
 * @riovcnt: size of rvec array
 * @flags: currently unused
 * @vm_write: 0 if reading from other process, 1 if writing to other process
 * Returns the number of bytes read/written or error code. May
 *  return less bytes than expected if an error occurs during the copying
 *  process.
 */
static ssize_t process_vm_rw(pid_t pid,
			     const struct iovec __user *lvec,
			     unsigned long liovcnt,
			     const struct iovec __user *rvec,
			     unsigned long riovcnt,
			     unsigned long flags, int vm_write)
{
	struct iovec iovstack_l[UIO_FASTIOV];
	struct iovec iovstack_r[UIO_FASTIOV];
	struct iovec *iov_l = iovstack_l;
	struct iovec *iov_r = iovstack_r;
	struct iov_iter iter;
	ssize_t rc;
	int dir = vm_write ? WRITE : READ;

	if (flags != 0)
		return -EINVAL;

	/* Check iovecs */
	rc = import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter);
	if (rc < 0)
		return rc;
	if (!iov_iter_count(&iter))
		goto free_iovecs;

	rc = rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV,
				   iovstack_r, &iov_r);
	if (rc <= 0)
		goto free_iovecs;

	rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);

free_iovecs:
	if (iov_r != iovstack_r)
		kfree(iov_r);
	kfree(iov_l);

	return rc;
}

SYSCALL_DEFINE6(process_vm_readv, pid_t, pid, const struct iovec __user *, lvec,
		unsigned long, liovcnt, const struct iovec __user *, rvec,
		unsigned long, riovcnt,	unsigned long, flags)
{
	return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 0);
}

SYSCALL_DEFINE6(process_vm_writev, pid_t, pid,
		const struct iovec __user *, lvec,
		unsigned long, liovcnt, const struct iovec __user *, rvec,
		unsigned long, riovcnt,	unsigned long, flags)
{
	return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 1);
}

#ifdef CONFIG_COMPAT

static ssize_t
compat_process_vm_rw(compat_pid_t pid,
		     const struct compat_iovec __user *lvec,
		     unsigned long liovcnt,
		     const struct compat_iovec __user *rvec,
		     unsigned long riovcnt,
		     unsigned long flags, int vm_write)
{
	struct iovec iovstack_l[UIO_FASTIOV];
	struct iovec iovstack_r[UIO_FASTIOV];
	struct iovec *iov_l = iovstack_l;
	struct iovec *iov_r = iovstack_r;
	struct iov_iter iter;
	ssize_t rc = -EFAULT;
	int dir = vm_write ? WRITE : READ;

	if (flags != 0)
		return -EINVAL;

	rc = compat_import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter);
	if (rc < 0)
		return rc;
	if (!iov_iter_count(&iter))
		goto free_iovecs;
	rc = compat_rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt,
					  UIO_FASTIOV, iovstack_r,
					  &iov_r);
	if (rc <= 0)
		goto free_iovecs;

	rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);

free_iovecs:
	if (iov_r != iovstack_r)
		kfree(iov_r);
	kfree(iov_l);
	return rc;
}

COMPAT_SYSCALL_DEFINE6(process_vm_readv, compat_pid_t, pid,
		       const struct compat_iovec __user *, lvec,
		       compat_ulong_t, liovcnt,
		       const struct compat_iovec __user *, rvec,
		       compat_ulong_t, riovcnt,
		       compat_ulong_t, flags)
{
	return compat_process_vm_rw(pid, lvec, liovcnt, rvec,
				    riovcnt, flags, 0);
}

COMPAT_SYSCALL_DEFINE6(process_vm_writev, compat_pid_t, pid,
		       const struct compat_iovec __user *, lvec,
		       compat_ulong_t, liovcnt,
		       const struct compat_iovec __user *, rvec,
		       compat_ulong_t, riovcnt,
		       compat_ulong_t, flags)
{
	return compat_process_vm_rw(pid, lvec, liovcnt, rvec,
				    riovcnt, flags, 1);
}

#endif
Commit	Line	Data
fcf63409 CY	1	/*
	2	* linux/mm/process_vm_access.c
	3	*
	4	* Copyright (C) 2010-2011 Christopher Yeoh <[email protected]>, IBM Corp.
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
	12	#include <linux/mm.h>
	13	#include <linux/uio.h>
	14	#include <linux/sched.h>
6e84f315	15	#include <linux/sched/mm.h>
fcf63409 CY	16	#include <linux/highmem.h>
	17	#include <linux/ptrace.h>
	18	#include <linux/slab.h>
	19	#include <linux/syscalls.h>
	20
	21	#ifdef CONFIG_COMPAT
	22	#include <linux/compat.h>
	23	#endif
	24
	25	/**
	26	* process_vm_rw_pages - read/write pages from task specified
4bafbec7	27	* @pages: array of pointers to pages we want to copy
fcf63409 CY	28	* @start_offset: offset in page to start copying from/to
fcf63409 CY	29	* @len: number of bytes to copy
4bafbec7	30	* @iter: where to copy to/from locally
fcf63409	31	* @vm_write: 0 means copy from, 1 means copy to
fcf63409 CY	32	* Returns 0 on success, error code otherwise
fcf63409 CY	33	*/
70eca12d AV	34	static int process_vm_rw_pages(struct page **pages,
70eca12d AV	35	unsigned offset,
e21345f9	36	size_t len,
9f78bdfa	37	struct iov_iter *iter,
9acc1a0f	38	int vm_write)
fcf63409	39	{
fcf63409	40	/* Do the copy for each page */
9acc1a0f	41	while (len && iov_iter_count(iter)) {
70eca12d	42	struct page page = pages++;
e21345f9	43	size_t copy = PAGE_SIZE - offset;
70eca12d	44	size_t copied;
240f3905	45
e21345f9 AV	46	if (copy > len)
	47	copy = len;
	48
240f3905	49	if (vm_write) {
e7c24607	50	copied = copy_page_from_iter(page, offset, copy, iter);
240f3905	51	set_page_dirty_lock(page);
fcf63409	52	} else {
70eca12d	53	copied = copy_page_to_iter(page, offset, copy, iter);
fcf63409	54	}
70eca12d AV	55	len -= copied;
	56	if (copied < copy && iov_iter_count(iter))
	57	return -EFAULT;
	58	offset = 0;
fcf63409	59	}
70eca12d	60	return 0;
fcf63409 CY	61	}
	62
	63	/* Maximum number of pages kmalloc'd to hold struct page's during copy */
	64	#define PVM_MAX_KMALLOC_PAGES (PAGE_SIZE * 2)
	65
	66	/**
	67	* process_vm_rw_single_vec - read/write pages from task specified
	68	* @addr: start memory address of target process
	69	* @len: size of area to copy to/from
4bafbec7	70	* @iter: where to copy to/from locally
fcf63409 CY	71	* @process_pages: struct pages area that can store at least
	72	* nr_pages_to_copy struct page pointers
	73	* @mm: mm for task
	74	* @task: task to read/write from
	75	* @vm_write: 0 means copy from, 1 means copy to
fcf63409 CY	76	* Returns 0 on success or on failure error code
	77	*/
	78	static int process_vm_rw_single_vec(unsigned long addr,
	79	unsigned long len,
9f78bdfa	80	struct iov_iter *iter,
fcf63409 CY	81	struct page **process_pages,
	82	struct mm_struct *mm,
	83	struct task_struct *task,
9acc1a0f	84	int vm_write)
fcf63409 CY	85	{
	86	unsigned long pa = addr & PAGE_MASK;
	87	unsigned long start_offset = addr - pa;
	88	unsigned long nr_pages;
fcf63409	89	ssize_t rc = 0;
fcf63409 CY	90	unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
fcf63409 CY	91	/ sizeof(struct pages *);
8b7457ef	92	unsigned int flags = 0;
fcf63409	93
fcf63409 CY	94	/* Work out address and page range required */
	95	if (len == 0)
	96	return 0;
	97	nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;
	98
d4944b0e LS	99	if (vm_write)
	100	flags \|= FOLL_WRITE;
	101
4bafbec7 AV	102	while (!rc && nr_pages && iov_iter_count(iter)) {
4bafbec7 AV	103	int pages = min(nr_pages, max_pages_per_loop);
8b7457ef	104	int locked = 1;
4bafbec7	105	size_t bytes;
fcf63409	106
1e987790 DH	107	/*
1e987790 DH	108	* Get the pages we're interested in. We must
8b7457ef	109	* access remotely because task/mm might not
1e987790 DH	110	* current/current->mm
1e987790 DH	111	*/
8b7457ef LS	112	down_read(&mm->mmap_sem);
	113	pages = get_user_pages_remote(task, mm, pa, pages, flags,
	114	process_pages, NULL, &locked);
	115	if (locked)
	116	up_read(&mm->mmap_sem);
4bafbec7	117	if (pages <= 0)
70eca12d AV	118	return -EFAULT;
70eca12d AV	119
4bafbec7 AV	120	bytes = pages * PAGE_SIZE - start_offset;
	121	if (bytes > len)
	122	bytes = len;
e21345f9	123
70eca12d	124	rc = process_vm_rw_pages(process_pages,
4bafbec7	125	start_offset, bytes, iter,
9acc1a0f	126	vm_write);
4bafbec7	127	len -= bytes;
fcf63409	128	start_offset = 0;
4bafbec7 AV	129	nr_pages -= pages;
	130	pa += pages * PAGE_SIZE;
	131	while (pages)
	132	put_page(process_pages[--pages]);
fcf63409 CY	133	}
	134
	135	return rc;
	136	}
	137
	138	/* Maximum number of entries for process pages array
	139	which lives on stack */
	140	#define PVM_MAX_PP_ARRAY_COUNT 16
	141
	142	/**
	143	* process_vm_rw_core - core of reading/writing pages from task specified
	144	* @pid: PID of process to read/write from/to
4bafbec7	145	* @iter: where to copy to/from locally
fcf63409 CY	146	* @rvec: iovec array specifying where to copy to/from in the other process
	147	* @riovcnt: size of rvec array
	148	* @flags: currently unused
	149	* @vm_write: 0 if reading from other process, 1 if writing to other process
	150	* Returns the number of bytes read/written or error code. May
	151	* return less bytes than expected if an error occurs during the copying
	152	* process.
	153	*/
9f78bdfa	154	static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
fcf63409 CY	155	const struct iovec *rvec,
	156	unsigned long riovcnt,
	157	unsigned long flags, int vm_write)
	158	{
	159	struct task_struct *task;
	160	struct page *pp_stack[PVM_MAX_PP_ARRAY_COUNT];
	161	struct page **process_pages = pp_stack;
	162	struct mm_struct *mm;
	163	unsigned long i;
	164	ssize_t rc = 0;
fcf63409 CY	165	unsigned long nr_pages = 0;
fcf63409 CY	166	unsigned long nr_pages_iov;
fcf63409	167	ssize_t iov_len;
9acc1a0f	168	size_t total_len = iov_iter_count(iter);
fcf63409 CY	169
	170	/*
	171	* Work out how many pages of struct pages we're going to need
	172	* when eventually calling get_user_pages
	173	*/
	174	for (i = 0; i < riovcnt; i++) {
	175	iov_len = rvec[i].iov_len;
	176	if (iov_len > 0) {
	177	nr_pages_iov = ((unsigned long)rvec[i].iov_base
	178	+ iov_len)
	179	/ PAGE_SIZE - (unsigned long)rvec[i].iov_base
	180	/ PAGE_SIZE + 1;
	181	nr_pages = max(nr_pages, nr_pages_iov);
	182	}
	183	}
	184
	185	if (nr_pages == 0)
	186	return 0;
	187
	188	if (nr_pages > PVM_MAX_PP_ARRAY_COUNT) {
	189	/* For reliability don't try to kmalloc more than
	190	2 pages worth */
	191	process_pages = kmalloc(min_t(size_t, PVM_MAX_KMALLOC_PAGES,
	192	sizeof(struct pages )nr_pages),
	193	GFP_KERNEL);
	194
	195	if (!process_pages)
	196	return -ENOMEM;
	197	}
	198
	199	/* Get process information */
	200	rcu_read_lock();
	201	task = find_task_by_vpid(pid);
	202	if (task)
	203	get_task_struct(task);
	204	rcu_read_unlock();
	205	if (!task) {
	206	rc = -ESRCH;
	207	goto free_proc_pages;
	208	}
	209
caaee623	210	mm = mm_access(task, PTRACE_MODE_ATTACH_REALCREDS);
8cdb878d CY	211	if (!mm \|\| IS_ERR(mm)) {
	212	rc = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
	213	/*
	214	* Explicitly map EACCES to EPERM as EPERM is a more a
	215	* appropriate error code for process_vw_readv/writev
	216	*/
	217	if (rc == -EACCES)
	218	rc = -EPERM;
fcf63409 CY	219	goto put_task_struct;
	220	}
	221
9acc1a0f	222	for (i = 0; i < riovcnt && iov_iter_count(iter) && !rc; i++)
fcf63409 CY	223	rc = process_vm_rw_single_vec(
fcf63409 CY	224	(unsigned long)rvec[i].iov_base, rvec[i].iov_len,
9acc1a0f AV	225	iter, process_pages, mm, task, vm_write);
	226
	227	/* copied = space before - space after */
	228	total_len -= iov_iter_count(iter);
	229
	230	/* If we have managed to copy any data at all then
	231	we return the number of bytes copied. Otherwise
	232	we return the error code */
	233	if (total_len)
	234	rc = total_len;
fcf63409	235
fcf63409 CY	236	mmput(mm);
	237
	238	put_task_struct:
	239	put_task_struct(task);
	240
	241	free_proc_pages:
	242	if (process_pages != pp_stack)
	243	kfree(process_pages);
	244	return rc;
	245	}
	246
	247	/**
	248	* process_vm_rw - check iovecs before calling core routine
	249	* @pid: PID of process to read/write from/to
	250	* @lvec: iovec array specifying where to copy to/from locally
	251	* @liovcnt: size of lvec array
	252	* @rvec: iovec array specifying where to copy to/from in the other process
	253	* @riovcnt: size of rvec array
	254	* @flags: currently unused
	255	* @vm_write: 0 if reading from other process, 1 if writing to other process
	256	* Returns the number of bytes read/written or error code. May
	257	* return less bytes than expected if an error occurs during the copying
	258	* process.
	259	*/
	260	static ssize_t process_vm_rw(pid_t pid,
	261	const struct iovec __user *lvec,
	262	unsigned long liovcnt,
	263	const struct iovec __user *rvec,
	264	unsigned long riovcnt,
	265	unsigned long flags, int vm_write)
	266	{
	267	struct iovec iovstack_l[UIO_FASTIOV];
	268	struct iovec iovstack_r[UIO_FASTIOV];
	269	struct iovec *iov_l = iovstack_l;
	270	struct iovec *iov_r = iovstack_r;
9f78bdfa	271	struct iov_iter iter;
fcf63409	272	ssize_t rc;
17d17e72	273	int dir = vm_write ? WRITE : READ;
fcf63409 CY	274
	275	if (flags != 0)
	276	return -EINVAL;
	277
	278	/* Check iovecs */
17d17e72 AV	279	rc = import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter);
	280	if (rc < 0)
	281	return rc;
	282	if (!iov_iter_count(&iter))
fcf63409 CY	283	goto free_iovecs;
fcf63409 CY	284
ac34ebb3 CY	285	rc = rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV,
ac34ebb3 CY	286	iovstack_r, &iov_r);
fcf63409 CY	287	if (rc <= 0)
	288	goto free_iovecs;
	289
9f78bdfa	290	rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);
fcf63409 CY	291
	292	free_iovecs:
	293	if (iov_r != iovstack_r)
	294	kfree(iov_r);
17d17e72	295	kfree(iov_l);
fcf63409 CY	296
	297	return rc;
	298	}
	299
	300	SYSCALL_DEFINE6(process_vm_readv, pid_t, pid, const struct iovec __user *, lvec,
	301	unsigned long, liovcnt, const struct iovec __user *, rvec,
	302	unsigned long, riovcnt, unsigned long, flags)
	303	{
	304	return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 0);
	305	}
	306
	307	SYSCALL_DEFINE6(process_vm_writev, pid_t, pid,
	308	const struct iovec __user *, lvec,
	309	unsigned long, liovcnt, const struct iovec __user *, rvec,
	310	unsigned long, riovcnt, unsigned long, flags)
	311	{
	312	return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 1);
	313	}
	314
	315	#ifdef CONFIG_COMPAT
	316
2eb2e141	317	static ssize_t
fcf63409 CY	318	compat_process_vm_rw(compat_pid_t pid,
	319	const struct compat_iovec __user *lvec,
	320	unsigned long liovcnt,
	321	const struct compat_iovec __user *rvec,
	322	unsigned long riovcnt,
	323	unsigned long flags, int vm_write)
	324	{
	325	struct iovec iovstack_l[UIO_FASTIOV];
	326	struct iovec iovstack_r[UIO_FASTIOV];
	327	struct iovec *iov_l = iovstack_l;
	328	struct iovec *iov_r = iovstack_r;
9f78bdfa	329	struct iov_iter iter;
fcf63409	330	ssize_t rc = -EFAULT;
17d17e72	331	int dir = vm_write ? WRITE : READ;
fcf63409 CY	332
	333	if (flags != 0)
	334	return -EINVAL;
	335
17d17e72 AV	336	rc = compat_import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter);
	337	if (rc < 0)
	338	return rc;
	339	if (!iov_iter_count(&iter))
fcf63409	340	goto free_iovecs;
ac34ebb3	341	rc = compat_rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt,
fcf63409	342	UIO_FASTIOV, iovstack_r,
ac34ebb3	343	&iov_r);
fcf63409 CY	344	if (rc <= 0)
	345	goto free_iovecs;
	346
9f78bdfa	347	rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);
fcf63409 CY	348
	349	free_iovecs:
	350	if (iov_r != iovstack_r)
	351	kfree(iov_r);
17d17e72	352	kfree(iov_l);
fcf63409 CY	353	return rc;
	354	}
	355
2f2728f6 HC	356	COMPAT_SYSCALL_DEFINE6(process_vm_readv, compat_pid_t, pid,
	357	const struct compat_iovec __user *, lvec,
	358	compat_ulong_t, liovcnt,
	359	const struct compat_iovec __user *, rvec,
	360	compat_ulong_t, riovcnt,
	361	compat_ulong_t, flags)
fcf63409 CY	362	{
	363	return compat_process_vm_rw(pid, lvec, liovcnt, rvec,
	364	riovcnt, flags, 0);
	365	}
	366
2f2728f6 HC	367	COMPAT_SYSCALL_DEFINE6(process_vm_writev, compat_pid_t, pid,
	368	const struct compat_iovec __user *, lvec,
	369	compat_ulong_t, liovcnt,
	370	const struct compat_iovec __user *, rvec,
	371	compat_ulong_t, riovcnt,
	372	compat_ulong_t, flags)
fcf63409 CY	373	{
	374	return compat_process_vm_rw(pid, lvec, liovcnt, rvec,
	375	riovcnt, flags, 1);
	376	}
	377
	378	#endif