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Commit 35db2a07 authored by Jens Axboe's avatar Jens Axboe Committed by Greg Kroah-Hartman
Browse files

random: convert to using fops->write_iter() 



commit 22b0a222af4df8ee9bb8e07013ab44da9511b047 upstream.

Now that the read side has been converted to fix a regression with
splice, convert the write side as well to have some symmetry in the
interface used (and help deprecate ->write()).

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
[Jason: cleaned up random_ioctl a bit, require full writes in
 RNDADDENTROPY since it's crediting entropy, simplify control flow of
 write_pool(), and incorporate suggestions from Al.]
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 43e62db8

drivers/char/random.c

+35 −32
Original line number Diff line number Diff line
@@ -1251,39 +1251,31 @@ static __poll_t random_poll(struct file *file, poll_table *wait) 
	return crng_ready() ? EPOLLIN | EPOLLRDNORM : EPOLLOUT | EPOLLWRNORM;

}



static int write_pool(const char __user *ubuf, size_t len)

static ssize_t write_pool(struct iov_iter *iter)

{

	size_t block_len;

	int ret = 0;

	u8 block[BLAKE2S_BLOCK_SIZE];

	ssize_t ret = 0;

	size_t copied;



	while (len) {

		block_len = min(len, sizeof(block));

		if (copy_from_user(block, ubuf, block_len)) {

			ret = -EFAULT;

			goto out;

		}

		len -= block_len;

		ubuf += block_len;

		mix_pool_bytes(block, block_len);

	if (unlikely(!iov_iter_count(iter)))

		return 0;



	for (;;) {

		copied = copy_from_iter(block, sizeof(block), iter);

		ret += copied;

		mix_pool_bytes(block, copied);

		if (!iov_iter_count(iter) || copied != sizeof(block))

			break;

		cond_resched();

	}



out:

	memzero_explicit(block, sizeof(block));

	return ret;

	return ret ? ret : -EFAULT;

}



static ssize_t random_write(struct file *file, const char __user *ubuf,

			    size_t len, loff_t *ppos)

static ssize_t random_write_iter(struct kiocb *kiocb, struct iov_iter *iter)

{

	int ret;



	ret = write_pool(ubuf, len);

	if (ret)

		return ret;



	return (ssize_t)len;

	return write_pool(iter);

}



static ssize_t urandom_read_iter(struct kiocb *kiocb, struct iov_iter *iter)
@@ -1315,9 +1307,8 @@ static ssize_t random_read_iter(struct kiocb *kiocb, struct iov_iter *iter) 


static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)

{

	int size, ent_count;

	int __user *p = (int __user *)arg;

	int retval;

	int ent_count;



	switch (cmd) {

	case RNDGETENTCNT:
@@ -1334,20 +1325,32 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg) 
			return -EINVAL;

		credit_init_bits(ent_count);

		return 0;

	case RNDADDENTROPY:

	case RNDADDENTROPY: {

		struct iov_iter iter;

		struct iovec iov;

		ssize_t ret;

		int len;



		if (!capable(CAP_SYS_ADMIN))

			return -EPERM;

		if (get_user(ent_count, p++))

			return -EFAULT;

		if (ent_count < 0)

			return -EINVAL;

		if (get_user(size, p++))

		if (get_user(len, p++))

			return -EFAULT;

		ret = import_single_range(WRITE, p, len, &iov, &iter);

		if (unlikely(ret))

			return ret;

		ret = write_pool(&iter);

		if (unlikely(ret < 0))

			return ret;

		/* Since we're crediting, enforce that it was all written into the pool. */

		if (unlikely(ret != len))

			return -EFAULT;

		retval = write_pool((const char __user *)p, size);

		if (retval < 0)

			return retval;

		credit_init_bits(ent_count);

		return 0;

	}

	case RNDZAPENTCNT:

	case RNDCLEARPOOL:

		/* No longer has any effect. */
@@ -1373,7 +1376,7 @@ static int random_fasync(int fd, struct file *filp, int on) 


const struct file_operations random_fops = {

	.read_iter = random_read_iter,

	.write = random_write,

	.write_iter = random_write_iter,

	.poll = random_poll,

	.unlocked_ioctl = random_ioctl,

	.compat_ioctl = compat_ptr_ioctl,
@@ -1383,7 +1386,7 @@ const struct file_operations random_fops = { 


const struct file_operations urandom_fops = {

	.read_iter = urandom_read_iter,

	.write = random_write,

	.write_iter = random_write_iter,

	.unlocked_ioctl = random_ioctl,

	.compat_ioctl = compat_ptr_ioctl,

	.fasync = random_fasync,