4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Al Viro viro@ZenIV.linux.org.uk
commit a5739435b5a3b8c449f8844ecd71a3b1e89f0a33 upstream.
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.
Acked-by: Tom Herbert tom@herbertland.com Signed-off-by: Al Viro viro@zeniv.linux.org.uk Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- net/kcm/kcmsock.c | 73 +++++++++++++++++++----------------------------------- 1 file changed, 26 insertions(+), 47 deletions(-)
--- a/net/kcm/kcmsock.c +++ b/net/kcm/kcmsock.c @@ -1624,60 +1624,35 @@ 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 (unlikely(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: - sock_release(newsock); -out: - return err; + file = sock_alloc_file(newsock, 0, osock->sk->sk_prot_creator->name); + if (IS_ERR(file)) + sock_release(newsock); + + return file; }
static int kcm_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg) @@ -1707,21 +1682,25 @@ static int kcm_ioctl(struct socket *sock } case SIOCKCMCLONE: { struct kcm_clone info; - struct socket *newsock = NULL; + struct file *file;
- if (copy_from_user(&info, (void __user *)arg, sizeof(info))) + 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))) { + put_unused_fd(info.fd); + fput(file); return -EFAULT; - - err = kcm_clone(sock, &info, &newsock); - - if (!err) { - if (copy_to_user((void __user *)arg, &info, - sizeof(info))) { - err = -EFAULT; - sys_close(info.fd); - } } - + fd_install(info.fd, file); + err = 0; break; } default: