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Commit a5739435 authored by Al Viro's avatar Al Viro Committed by David S. Miller
Browse files

fix kcm_clone() 



1) it's fput() or sock_release(), not both
2) don't do fd_install() until the last failure exit.
3) not a bug per se, but... don't attach socket to struct file
   until it's set up.

Take reserving descriptor into the caller, move fd_install() to the
caller, sanitize failure exits and calling conventions.

Cc: stable@vger.kernel.org # v4.6+
Acked-by: default avatarTom Herbert <tom@herbertland.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 69c64866

net/kcm/kcmsock.c

+27 −44
Original line number Diff line number Diff line
@@ -1625,60 +1625,35 @@ static struct proto kcm_proto = { 
};



/* Clone a kcm socket. */

static int kcm_clone(struct socket *osock, struct kcm_clone *info,

		     struct socket **newsockp)

static struct file *kcm_clone(struct socket *osock)

{

	struct socket *newsock;

	struct sock *newsk;

	struct file *newfile;

	int err, newfd;

	struct file *file;



	err = -ENFILE;

	newsock = sock_alloc();

	if (!newsock)

		goto out;

		return ERR_PTR(-ENFILE);



	newsock->type = osock->type;

	newsock->ops = osock->ops;



	__module_get(newsock->ops->owner);



	newfd = get_unused_fd_flags(0);

	if (unlikely(newfd < 0)) {

		err = newfd;

		goto out_fd_fail;

	}



	newfile = sock_alloc_file(newsock, 0, osock->sk->sk_prot_creator->name);

	if (IS_ERR(newfile)) {

		err = PTR_ERR(newfile);

		goto out_sock_alloc_fail;

	}



	newsk = sk_alloc(sock_net(osock->sk), PF_KCM, GFP_KERNEL,

			 &kcm_proto, true);

	if (!newsk) {

		err = -ENOMEM;

		goto out_sk_alloc_fail;

		sock_release(newsock);

		return ERR_PTR(-ENOMEM);

	}



	sock_init_data(newsock, newsk);

	init_kcm_sock(kcm_sk(newsk), kcm_sk(osock->sk)->mux);



	fd_install(newfd, newfile);

	*newsockp = newsock;

	info->fd = newfd;



	return 0;



out_sk_alloc_fail:

	fput(newfile);

out_sock_alloc_fail:

	put_unused_fd(newfd);

out_fd_fail:

	file = sock_alloc_file(newsock, 0, osock->sk->sk_prot_creator->name);

	if (IS_ERR(file))

		sock_release(newsock);

out:

	return err;



	return file;

}



static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
@@ -1708,17 +1683,25 @@ static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) 
	}

	case SIOCKCMCLONE: {

		struct kcm_clone info;

		struct socket *newsock = NULL;

		struct file *file;



		err = kcm_clone(sock, &info, &newsock);

		if (!err) {

		info.fd = get_unused_fd_flags(0);

		if (unlikely(info.fd < 0))

			return info.fd;



		file = kcm_clone(sock);

		if (IS_ERR(file)) {

			put_unused_fd(info.fd);

			return PTR_ERR(file);

		}

		if (copy_to_user((void __user *)arg, &info,

				 sizeof(info))) {

				err = -EFAULT;

				sys_close(info.fd);

			}

			put_unused_fd(info.fd);

			fput(file);

			return -EFAULT;

		}



		fd_install(info.fd, file);

		err = 0;

		break;

	}

	default: