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fix kcm_clone()

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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: Tom Herbert <tom@herbertland.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Al Viro 2017-12-05 23:27:57 +00:00 committed by David S. Miller
parent 69c64866ce
commit a5739435b5
1 changed files with 26 additions and 43 deletions
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69
net/kcm/kcmsock.c
View File

@ -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;
file = sock_alloc_file(newsock, 0, osock->sk->sk_prot_creator->name);
if (IS_ERR(file))
sock_release(newsock);
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;
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) {
if (copy_to_user((void __user *)arg, &info,
sizeof(info))) {
err = -EFAULT;
sys_close(info.fd);
}
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;
}
fd_install(info.fd, file);
err = 0;
break;
}
default: