From: Al Viro <viro@zeniv.linux.org.uk>
To: Christian Brauner <christian.brauner@ubuntu.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
Xie Yongji <xieyongji@bytedance.com>,
hch@infradead.org, arve@android.com, tkjos@android.com,
maco@android.com, joel@joelfernandes.org, hridya@google.com,
surenb@google.com, sargun@sargun.me, keescook@chromium.org,
jasowang@redhat.com, devel@driverdev.osuosl.org,
linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 2/2] binder: Use receive_fd() to receive file from another process
Date: Fri, 16 Apr 2021 17:00:11 +0000 [thread overview]
Message-ID: <YHnCm0Zzi+envOGB@zeniv-ca.linux.org.uk> (raw)
In-Reply-To: <20210416160038.ojbhqf73dkrl4dk6@wittgenstein>
On Fri, Apr 16, 2021 at 06:00:38PM +0200, Christian Brauner wrote:
> (dma_buf_fd() seems like another good candidate. But again, I don't have
> any plans to shove this down anyone's throat.)
Sure, there are candidates for such a helper. Just as there are legitimate
users of anon_inode_getfd().
However, it is *NOT* something we can use as a vehicle for some hooks (pardon
the obscenity); it won't be consistently used in all cases - it simply is not
feasible for many of the fd_install() users.
Incidentally, looking at the user of receive_fd_user(), I would say that it
would be easier to follow in this form:
case VDUSE_IOTLB_GET_ENTRY: {
struct vduse_iotlb_entry entry;
struct vhost_iotlb_map *map;
struct vduse_iova_domain *domain = dev->domain;
struct file *f = NULL;
if (copy_from_user(&entry, argp, sizeof(entry)))
return -EFAULT;
entry.fd = get_unused_fd_flags(perm_to_file_flags(entry.perm));
if (entry.fd < 0)
return entry.fd;
spin_lock(&domain->iotlb_lock);
map = vhost_iotlb_itree_first(domain->iotlb,
entry.start, entry.start + 1);
if (map) {
struct vdpa_map_file *map_file = map->opaque;
f = get_file(map_file->file);
entry.offset = map_file->offset;
entry.start = map->start;
entry.last = map->last;
entry.perm = map->perm;
}
spin_unlock(&domain->iotlb_lock);
if (!f) {
put_unused_fd(entry.fd);
return -EINVAL;
}
if (copy_to_user(argp, &entry, sizeof(entry))) {
put_unused_fd(entry.fd);
fput(f);
return -EFAULT;
}
// point of no return
fd_install(entry.fd, f);
return 0;
}
next prev parent reply other threads:[~2021-04-16 17:00 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-01 9:09 [PATCH 0/2] Export receive_fd() to modules and do some cleanups Xie Yongji
2021-04-01 9:09 ` [PATCH 1/2] file: Export receive_fd() to modules Xie Yongji
2021-04-01 9:52 ` Greg KH
2021-04-01 10:24 ` Yongji Xie
2021-04-01 9:09 ` [PATCH 2/2] binder: Use receive_fd() to receive file from another process Xie Yongji
2021-04-01 9:54 ` Greg KH
2021-04-01 10:12 ` Yongji Xie
2021-04-01 10:42 ` Greg KH
2021-04-01 11:29 ` Yongji Xie
2021-04-01 11:33 ` Greg KH
2021-04-01 12:28 ` Yongji Xie
2021-04-01 14:09 ` Greg KH
2021-04-02 9:12 ` Kees Cook
2021-04-01 10:40 ` Christian Brauner
2021-04-01 11:11 ` Yongji Xie
2021-04-16 5:19 ` Al Viro
2021-04-16 5:55 ` Al Viro
2021-04-16 13:42 ` Christian Brauner
2021-04-16 14:09 ` Al Viro
2021-04-16 15:13 ` Christian Brauner
2021-04-16 15:35 ` Al Viro
2021-04-16 15:58 ` Christian Brauner
2021-04-16 16:00 ` Christian Brauner
2021-04-16 17:00 ` Al Viro [this message]
2021-04-16 17:30 ` Al Viro
2021-04-17 1:30 ` Al Viro
2021-04-01 9:53 ` [PATCH 0/2] Export receive_fd() to modules and do some cleanups Greg KH
2021-04-01 10:00 ` Yongji Xie
2021-04-01 10:20 ` Christian Brauner
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