From: Miklos Szeredi <miklos@szeredi.hu>
To: "Ahelenia Ziemiańska" <nabijaczleweli@nabijaczleweli.xyz>
Cc: Jens Axboe <axboe@kernel.dk>,
Christian Brauner <brauner@kernel.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
linux-fsdevel@vger.kernel.org, Vivek Goyal <vgoyal@redhat.com>,
Stefan Hajnoczi <stefanha@redhat.com>,
linux-kernel@vger.kernel.org, virtualization@lists.linux.dev
Subject: Re: [PATCH v2 09/11] fuse: file: limit splice_read to virtiofs
Date: Wed, 10 Jan 2024 14:43:04 +0100 [thread overview]
Message-ID: <CAJfpegugS1y4Lwznju+qD2K-kBEctxU5ABCnaE2eOGhtFFZUYg@mail.gmail.com> (raw)
In-Reply-To: <9b5cd13bc9e9c570978ec25b25ba5e4081b3d56b.1703126594.git.nabijaczleweli@nabijaczleweli.xyz>
On Thu, 21 Dec 2023 at 04:09, Ahelenia Ziemiańska
<nabijaczleweli@nabijaczleweli.xyz> wrote:
>
> Potentially-blocking splice_reads are allowed for normal filesystems
> like NFS because they're blessed by root.
>
> FUSE is commonly used suid-root, and allows anyone to trivially create
> a file that, when spliced from, will just sleep forever with the pipe
> lock held.
>
> The only way IPC to the fusing process could be avoided is if
> !(ff->open_flags & FOPEN_DIRECT_IO) and the range was already cached
> and we weren't past the end. Just refuse it.
How is this not going to cause regressions out there?
We need to find an alternative to refusing splice, since this is not
going to fly, IMO.
Thanks,
Miklos
next prev parent reply other threads:[~2024-01-10 13:43 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-21 3:08 [PATCH v2 00/11] Avoid unprivileged splice(file->)/(->socket) pipe exclusion Ahelenia Ziemiańska
2023-12-21 3:08 ` [PATCH v2 01/11] splice: copy_splice_read: do the I/O with IOCB_NOWAIT Ahelenia Ziemiańska
2023-12-21 8:27 ` Christoph Hellwig
2023-12-21 16:30 ` Ahelenia Ziemiańska
2023-12-21 3:08 ` [PATCH v2 02/11] af_unix: unix_stream_splice_read: always request MSG_DONTWAIT Ahelenia Ziemiańska
2023-12-21 3:08 ` [PATCH v2 03/11] fuse: fuse_dev_splice_read: use nonblocking I/O Ahelenia Ziemiańska
2023-12-21 3:09 ` [PATCH v2 04/11] net/smc: smc_splice_read: always request MSG_DONTWAIT Ahelenia Ziemiańska
2023-12-21 3:09 ` [PATCH v2 05/11] kcm: kcm_splice_read: " Ahelenia Ziemiańska
2023-12-21 3:09 ` [PATCH v2 06/11] tls/sw: tls_sw_splice_read: always request non-blocking I/O Ahelenia Ziemiańska
2023-12-21 3:09 ` [PATCH v2 07/11] net/tcp: tcp_splice_read: always do non-blocking reads Ahelenia Ziemiańska
2023-12-21 3:09 ` [PATCH v2 08/11] tty: splice_read: disable Ahelenia Ziemiańska
2023-12-21 8:10 ` Greg Kroah-Hartman
2024-01-03 11:36 ` Jiri Slaby
2024-01-03 19:14 ` Linus Torvalds
2024-01-03 21:34 ` Oliver Giles
2024-01-03 21:57 ` Linus Torvalds
2023-12-21 3:09 ` [PATCH v2 09/11] fuse: file: limit splice_read to virtiofs Ahelenia Ziemiańska
2024-01-10 13:43 ` Miklos Szeredi [this message]
2024-01-10 15:19 ` Ahelenia Ziemiańska
2024-01-10 15:47 ` Miklos Szeredi
2023-12-21 3:09 ` [PATCH v2 10/11] fuse: allow splicing from filesystems mounted by real root Ahelenia Ziemiańska
2023-12-21 3:09 ` [PATCH v2 11/11] splice: splice_to_socket: always request MSG_DONTWAIT Ahelenia Ziemiańska
2023-12-21 3:09 ` [PATCH v2 12/11 man-pages] splice.2: document 6.8 blocking behaviour Ahelenia Ziemiańska
2023-12-24 5:01 ` [PATCH v2 13/11] tty: splice_write: disable Ahelenia Ziemiańska
2023-12-24 5:01 ` [PATCH v2 14/11] fuse: allow splicing to trusted mounts only Ahelenia Ziemiańska
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