4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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: