Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 7f397dcd authored by Matt Mackall's avatar Matt Mackall Committed by Linus Torvalds
Browse files

random: fix seeding with zero entropy 



Add data from zero-entropy random_writes directly to output pools to
avoid accounting difficulties on machines without entropy sources.

Tested on lguest with all entropy sources disabled.

Signed-off-by: default avatarMatt Mackall <mpm@selenic.com>
Acked-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 602b6aee

drivers/char/random.c

+31 −24
Original line number Original line Diff line number Diff line
@@ -1020,37 +1020,44 @@ random_poll(struct file *file, poll_table * wait) 
	return mask;

	return mask;

}

}





static ssize_t

static int

random_write(struct file * file, const char __user * buffer,

write_pool(struct entropy_store *r, const char __user *buffer, size_t count)

	     size_t count, loff_t *ppos)

{

{

	int ret = 0;

	size_t bytes;

	size_t bytes;

	__u32 buf[16];

	__u32 buf[16];

	const char __user *p = buffer;

	const char __user *p = buffer;

	size_t c = count;





	while (c > 0) {

	while (count > 0) {

		bytes = min(c, sizeof(buf));

		bytes = min(count, sizeof(buf));

		if (copy_from_user(&buf, p, bytes))

			return -EFAULT;





		bytes -= copy_from_user(&buf, p, bytes);

		count -= bytes;

		if (!bytes) {

			ret = -EFAULT;

			break;

		}

		c -= bytes;

		p += bytes;

		p += bytes;





		add_entropy_words(&input_pool, buf, (bytes + 3) / 4);

		add_entropy_words(r, buf, (bytes + 3) / 4);

	}

	}

	if (p == buffer) {



		return (ssize_t)ret;

	return 0;

	} else {

}



static ssize_t

random_write(struct file * file, const char __user * buffer,

	     size_t count, loff_t *ppos)

{

	size_t ret;

	struct inode *inode = file->f_path.dentry->d_inode;

	struct inode *inode = file->f_path.dentry->d_inode;



	ret = write_pool(&blocking_pool, buffer, count);

	if (ret)

		return ret;

	ret = write_pool(&nonblocking_pool, buffer, count);

	if (ret)

		return ret;



	inode->i_mtime = current_fs_time(inode->i_sb);

	inode->i_mtime = current_fs_time(inode->i_sb);

	mark_inode_dirty(inode);

	mark_inode_dirty(inode);

		return (ssize_t)(p - buffer);

	return (ssize_t)count;

	}

}

}





static int

static int
@@ -1089,8 +1096,8 @@ random_ioctl(struct inode * inode, struct file * file, 
			return -EINVAL;

			return -EINVAL;

		if (get_user(size, p++))

		if (get_user(size, p++))

			return -EFAULT;

			return -EFAULT;

		retval = random_write(file, (const char __user *) p,

		retval = write_pool(&input_pool, (const char __user *)p,

				      size, &file->f_pos);

				    size);

		if (retval < 0)

		if (retval < 0)

			return retval;

			return retval;

		credit_entropy_store(&input_pool, ent_count);

		credit_entropy_store(&input_pool, ent_count);