[mirror_ubuntu-jammy-kernel.git] / mm / process_vm_access.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * linux/mm/process_vm_access.c
 *
 * Copyright (C) 2010-2011 Christopher Yeoh <cyeoh@au1.ibm.com>, IBM Corp.
 */

#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
 * @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);
		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 pinned_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
		 */
		mmap_read_lock(mm);
		pinned_pages = pin_user_pages_remote(mm, pa, pinned_pages,
						     flags, process_pages,
						     NULL, &locked);
		if (locked)
			mmap_read_unlock(mm);
		if (pinned_pages <= 0)
			return -EFAULT;

		bytes = pinned_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 -= pinned_pages;
		pa += pinned_pages * PAGE_SIZE;

		/* If vm_write is set, the pages need to be made dirty: */
		unpin_user_pages_dirty_lock(process_pages, pinned_pages,
					    vm_write);
	}

	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 */
	task = find_get_task_by_vpid(pid);
	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
		 * 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
2874c5fd	1	// SPDX-License-Identifier: GPL-2.0-or-later
fcf63409 CY	2	/*
	3	* linux/mm/process_vm_access.c
	4	*
	5	* Copyright (C) 2010-2011 Christopher Yeoh <cyeoh@au1.ibm.com>, IBM Corp.
fcf63409 CY	6	*/
	7
	8	#include <linux/mm.h>
	9	#include <linux/uio.h>
	10	#include <linux/sched.h>
6e84f315	11	#include <linux/sched/mm.h>
fcf63409 CY	12	#include <linux/highmem.h>
	13	#include <linux/ptrace.h>
	14	#include <linux/slab.h>
	15	#include <linux/syscalls.h>
	16
	17	#ifdef CONFIG_COMPAT
	18	#include <linux/compat.h>
	19	#endif
	20
	21	/**
	22	* process_vm_rw_pages - read/write pages from task specified
4bafbec7	23	* @pages: array of pointers to pages we want to copy
f144c390	24	* @offset: offset in page to start copying from/to
fcf63409	25	* @len: number of bytes to copy
4bafbec7	26	* @iter: where to copy to/from locally
fcf63409	27	* @vm_write: 0 means copy from, 1 means copy to
fcf63409 CY	28	* Returns 0 on success, error code otherwise
fcf63409 CY	29	*/
70eca12d AV	30	static int process_vm_rw_pages(struct page **pages,
70eca12d AV	31	unsigned offset,
e21345f9	32	size_t len,
9f78bdfa	33	struct iov_iter *iter,
9acc1a0f	34	int vm_write)
fcf63409	35	{
fcf63409	36	/* Do the copy for each page */
9acc1a0f	37	while (len && iov_iter_count(iter)) {
70eca12d	38	struct page page = pages++;
e21345f9	39	size_t copy = PAGE_SIZE - offset;
70eca12d	40	size_t copied;
240f3905	41
e21345f9 AV	42	if (copy > len)
	43	copy = len;
	44
803e4572	45	if (vm_write)
e7c24607	46	copied = copy_page_from_iter(page, offset, copy, iter);
803e4572	47	else
70eca12d	48	copied = copy_page_to_iter(page, offset, copy, iter);
803e4572	49
70eca12d AV	50	len -= copied;
	51	if (copied < copy && iov_iter_count(iter))
	52	return -EFAULT;
	53	offset = 0;
fcf63409	54	}
70eca12d	55	return 0;
fcf63409 CY	56	}
	57
	58	/* Maximum number of pages kmalloc'd to hold struct page's during copy */
	59	#define PVM_MAX_KMALLOC_PAGES (PAGE_SIZE * 2)
	60
	61	/**
	62	* process_vm_rw_single_vec - read/write pages from task specified
	63	* @addr: start memory address of target process
	64	* @len: size of area to copy to/from
4bafbec7	65	* @iter: where to copy to/from locally
fcf63409 CY	66	* @process_pages: struct pages area that can store at least
	67	* nr_pages_to_copy struct page pointers
	68	* @mm: mm for task
	69	* @task: task to read/write from
	70	* @vm_write: 0 means copy from, 1 means copy to
fcf63409 CY	71	* Returns 0 on success or on failure error code
	72	*/
	73	static int process_vm_rw_single_vec(unsigned long addr,
	74	unsigned long len,
9f78bdfa	75	struct iov_iter *iter,
fcf63409 CY	76	struct page **process_pages,
	77	struct mm_struct *mm,
	78	struct task_struct *task,
9acc1a0f	79	int vm_write)
fcf63409 CY	80	{
	81	unsigned long pa = addr & PAGE_MASK;
	82	unsigned long start_offset = addr - pa;
	83	unsigned long nr_pages;
fcf63409	84	ssize_t rc = 0;
fcf63409 CY	85	unsigned long max_pages_per_loop = PVM_MAX_KMALLOC_PAGES
fcf63409 CY	86	/ sizeof(struct pages *);
8b7457ef	87	unsigned int flags = 0;
fcf63409	88
fcf63409 CY	89	/* Work out address and page range required */
	90	if (len == 0)
	91	return 0;
	92	nr_pages = (addr + len - 1) / PAGE_SIZE - addr / PAGE_SIZE + 1;
	93
d4944b0e LS	94	if (vm_write)
	95	flags \|= FOLL_WRITE;
	96
4bafbec7	97	while (!rc && nr_pages && iov_iter_count(iter)) {
803e4572	98	int pinned_pages = min(nr_pages, max_pages_per_loop);
8b7457ef	99	int locked = 1;
4bafbec7	100	size_t bytes;
fcf63409	101
1e987790 DH	102	/*
1e987790 DH	103	* Get the pages we're interested in. We must
8b7457ef	104	* access remotely because task/mm might not
1e987790 DH	105	* current/current->mm
1e987790 DH	106	*/
d8ed45c5	107	mmap_read_lock(mm);
64019a2e	108	pinned_pages = pin_user_pages_remote(mm, pa, pinned_pages,
803e4572 JH	109	flags, process_pages,
803e4572 JH	110	NULL, &locked);
8b7457ef	111	if (locked)
d8ed45c5	112	mmap_read_unlock(mm);
803e4572	113	if (pinned_pages <= 0)
70eca12d AV	114	return -EFAULT;
70eca12d AV	115
803e4572	116	bytes = pinned_pages * PAGE_SIZE - start_offset;
4bafbec7 AV	117	if (bytes > len)
4bafbec7 AV	118	bytes = len;
e21345f9	119
70eca12d	120	rc = process_vm_rw_pages(process_pages,
4bafbec7	121	start_offset, bytes, iter,
9acc1a0f	122	vm_write);
4bafbec7	123	len -= bytes;
fcf63409	124	start_offset = 0;
803e4572 JH	125	nr_pages -= pinned_pages;
	126	pa += pinned_pages * PAGE_SIZE;
	127
	128	/* If vm_write is set, the pages need to be made dirty: */
f1f6a7dd JH	129	unpin_user_pages_dirty_lock(process_pages, pinned_pages,
f1f6a7dd JH	130	vm_write);
fcf63409 CY	131	}
	132
	133	return rc;
	134	}
	135
	136	/* Maximum number of entries for process pages array
	137	which lives on stack */
	138	#define PVM_MAX_PP_ARRAY_COUNT 16
	139
	140	/**
	141	* process_vm_rw_core - core of reading/writing pages from task specified
	142	* @pid: PID of process to read/write from/to
4bafbec7	143	* @iter: where to copy to/from locally
fcf63409 CY	144	* @rvec: iovec array specifying where to copy to/from in the other process
	145	* @riovcnt: size of rvec array
	146	* @flags: currently unused
	147	* @vm_write: 0 if reading from other process, 1 if writing to other process
a5d09bed	148	*
fcf63409 CY	149	* Returns the number of bytes read/written or error code. May
	150	* return less bytes than expected if an error occurs during the copying
	151	* process.
	152	*/
9f78bdfa	153	static ssize_t process_vm_rw_core(pid_t pid, struct iov_iter *iter,
fcf63409 CY	154	const struct iovec *rvec,
	155	unsigned long riovcnt,
	156	unsigned long flags, int vm_write)
	157	{
	158	struct task_struct *task;
	159	struct page *pp_stack[PVM_MAX_PP_ARRAY_COUNT];
	160	struct page **process_pages = pp_stack;
	161	struct mm_struct *mm;
	162	unsigned long i;
	163	ssize_t rc = 0;
fcf63409 CY	164	unsigned long nr_pages = 0;
fcf63409 CY	165	unsigned long nr_pages_iov;
fcf63409	166	ssize_t iov_len;
9acc1a0f	167	size_t total_len = iov_iter_count(iter);
fcf63409 CY	168
	169	/*
	170	* Work out how many pages of struct pages we're going to need
	171	* when eventually calling get_user_pages
	172	*/
	173	for (i = 0; i < riovcnt; i++) {
	174	iov_len = rvec[i].iov_len;
	175	if (iov_len > 0) {
	176	nr_pages_iov = ((unsigned long)rvec[i].iov_base
	177	+ iov_len)
	178	/ PAGE_SIZE - (unsigned long)rvec[i].iov_base
	179	/ PAGE_SIZE + 1;
	180	nr_pages = max(nr_pages, nr_pages_iov);
	181	}
	182	}
	183
	184	if (nr_pages == 0)
	185	return 0;
	186
	187	if (nr_pages > PVM_MAX_PP_ARRAY_COUNT) {
	188	/* For reliability don't try to kmalloc more than
	189	2 pages worth */
	190	process_pages = kmalloc(min_t(size_t, PVM_MAX_KMALLOC_PAGES,
	191	sizeof(struct pages )nr_pages),
	192	GFP_KERNEL);
	193
	194	if (!process_pages)
	195	return -ENOMEM;
	196	}
	197
	198	/* Get process information */
2ee08260	199	task = find_get_task_by_vpid(pid);
fcf63409 CY	200	if (!task) {
	201	rc = -ESRCH;
	202	goto free_proc_pages;
	203	}
	204
caaee623	205	mm = mm_access(task, PTRACE_MODE_ATTACH_REALCREDS);
8cdb878d CY	206	if (!mm \|\| IS_ERR(mm)) {
	207	rc = IS_ERR(mm) ? PTR_ERR(mm) : -ESRCH;
	208	/*
8d09db80	209	* Explicitly map EACCES to EPERM as EPERM is a more
8cdb878d CY	210	* appropriate error code for process_vw_readv/writev
	211	*/
	212	if (rc == -EACCES)
	213	rc = -EPERM;
fcf63409 CY	214	goto put_task_struct;
	215	}
	216
9acc1a0f	217	for (i = 0; i < riovcnt && iov_iter_count(iter) && !rc; i++)
fcf63409 CY	218	rc = process_vm_rw_single_vec(
fcf63409 CY	219	(unsigned long)rvec[i].iov_base, rvec[i].iov_len,
9acc1a0f AV	220	iter, process_pages, mm, task, vm_write);
	221
	222	/* copied = space before - space after */
	223	total_len -= iov_iter_count(iter);
	224
	225	/* If we have managed to copy any data at all then
	226	we return the number of bytes copied. Otherwise
	227	we return the error code */
	228	if (total_len)
	229	rc = total_len;
fcf63409	230
fcf63409 CY	231	mmput(mm);
	232
	233	put_task_struct:
	234	put_task_struct(task);
	235
	236	free_proc_pages:
	237	if (process_pages != pp_stack)
	238	kfree(process_pages);
	239	return rc;
	240	}
	241
	242	/**
	243	* process_vm_rw - check iovecs before calling core routine
	244	* @pid: PID of process to read/write from/to
	245	* @lvec: iovec array specifying where to copy to/from locally
	246	* @liovcnt: size of lvec array
	247	* @rvec: iovec array specifying where to copy to/from in the other process
	248	* @riovcnt: size of rvec array
	249	* @flags: currently unused
	250	* @vm_write: 0 if reading from other process, 1 if writing to other process
a5d09bed	251	*
fcf63409 CY	252	* Returns the number of bytes read/written or error code. May
	253	* return less bytes than expected if an error occurs during the copying
	254	* process.
	255	*/
	256	static ssize_t process_vm_rw(pid_t pid,
	257	const struct iovec __user *lvec,
	258	unsigned long liovcnt,
	259	const struct iovec __user *rvec,
	260	unsigned long riovcnt,
	261	unsigned long flags, int vm_write)
	262	{
	263	struct iovec iovstack_l[UIO_FASTIOV];
	264	struct iovec iovstack_r[UIO_FASTIOV];
	265	struct iovec *iov_l = iovstack_l;
	266	struct iovec *iov_r = iovstack_r;
9f78bdfa	267	struct iov_iter iter;
fcf63409	268	ssize_t rc;
17d17e72	269	int dir = vm_write ? WRITE : READ;
fcf63409 CY	270
	271	if (flags != 0)
	272	return -EINVAL;
	273
	274	/* Check iovecs */
17d17e72 AV	275	rc = import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter);
	276	if (rc < 0)
	277	return rc;
	278	if (!iov_iter_count(&iter))
fcf63409 CY	279	goto free_iovecs;
fcf63409 CY	280
ac34ebb3 CY	281	rc = rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt, UIO_FASTIOV,
ac34ebb3 CY	282	iovstack_r, &iov_r);
fcf63409 CY	283	if (rc <= 0)
	284	goto free_iovecs;
	285
9f78bdfa	286	rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);
fcf63409 CY	287
	288	free_iovecs:
	289	if (iov_r != iovstack_r)
	290	kfree(iov_r);
17d17e72	291	kfree(iov_l);
fcf63409 CY	292
	293	return rc;
	294	}
	295
	296	SYSCALL_DEFINE6(process_vm_readv, pid_t, pid, const struct iovec __user *, lvec,
	297	unsigned long, liovcnt, const struct iovec __user *, rvec,
	298	unsigned long, riovcnt, unsigned long, flags)
	299	{
	300	return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 0);
	301	}
	302
	303	SYSCALL_DEFINE6(process_vm_writev, pid_t, pid,
	304	const struct iovec __user *, lvec,
	305	unsigned long, liovcnt, const struct iovec __user *, rvec,
	306	unsigned long, riovcnt, unsigned long, flags)
	307	{
	308	return process_vm_rw(pid, lvec, liovcnt, rvec, riovcnt, flags, 1);
	309	}
	310
	311	#ifdef CONFIG_COMPAT
	312
2eb2e141	313	static ssize_t
fcf63409 CY	314	compat_process_vm_rw(compat_pid_t pid,
	315	const struct compat_iovec __user *lvec,
	316	unsigned long liovcnt,
	317	const struct compat_iovec __user *rvec,
	318	unsigned long riovcnt,
	319	unsigned long flags, int vm_write)
	320	{
	321	struct iovec iovstack_l[UIO_FASTIOV];
	322	struct iovec iovstack_r[UIO_FASTIOV];
	323	struct iovec *iov_l = iovstack_l;
	324	struct iovec *iov_r = iovstack_r;
9f78bdfa	325	struct iov_iter iter;
fcf63409	326	ssize_t rc = -EFAULT;
17d17e72	327	int dir = vm_write ? WRITE : READ;
fcf63409 CY	328
	329	if (flags != 0)
	330	return -EINVAL;
	331
17d17e72 AV	332	rc = compat_import_iovec(dir, lvec, liovcnt, UIO_FASTIOV, &iov_l, &iter);
	333	if (rc < 0)
	334	return rc;
	335	if (!iov_iter_count(&iter))
fcf63409	336	goto free_iovecs;
ac34ebb3	337	rc = compat_rw_copy_check_uvector(CHECK_IOVEC_ONLY, rvec, riovcnt,
fcf63409	338	UIO_FASTIOV, iovstack_r,
ac34ebb3	339	&iov_r);
fcf63409 CY	340	if (rc <= 0)
	341	goto free_iovecs;
	342
9f78bdfa	343	rc = process_vm_rw_core(pid, &iter, iov_r, riovcnt, flags, vm_write);
fcf63409 CY	344
	345	free_iovecs:
	346	if (iov_r != iovstack_r)
	347	kfree(iov_r);
17d17e72	348	kfree(iov_l);
fcf63409 CY	349	return rc;
	350	}
	351
2f2728f6 HC	352	COMPAT_SYSCALL_DEFINE6(process_vm_readv, compat_pid_t, pid,
	353	const struct compat_iovec __user *, lvec,
	354	compat_ulong_t, liovcnt,
	355	const struct compat_iovec __user *, rvec,
	356	compat_ulong_t, riovcnt,
	357	compat_ulong_t, flags)
fcf63409 CY	358	{
	359	return compat_process_vm_rw(pid, lvec, liovcnt, rvec,
	360	riovcnt, flags, 0);
	361	}
	362
2f2728f6 HC	363	COMPAT_SYSCALL_DEFINE6(process_vm_writev, compat_pid_t, pid,
	364	const struct compat_iovec __user *, lvec,
	365	compat_ulong_t, liovcnt,
	366	const struct compat_iovec __user *, rvec,
	367	compat_ulong_t, riovcnt,
	368	compat_ulong_t, flags)
fcf63409 CY	369	{
	370	return compat_process_vm_rw(pid, lvec, liovcnt, rvec,
	371	riovcnt, flags, 1);
	372	}
	373
	374	#endif