From: Al Viro <viro@zeniv.linux.org.uk>
To: Sargun Dhillon <sargun@sargun.me>
Cc: linux-kernel@vger.kernel.org,
containers@lists.linux-foundation.org, linux-api@vger.kernel.org,
christian.brauner@ubuntu.com, tycho@tycho.ws,
keescook@chromium.org, cyphar@cyphar.com,
Jeffrey Vander Stoep <jeffv@google.com>,
jannh@google.com, rsesek@google.com, palmer@google.com,
Matt Denton <mpdenton@google.com>,
Kees Cook <keescook@google.com>
Subject: Re: [PATCH 2/5] seccomp: Introduce addfd ioctl to seccomp user notifier
Date: Mon, 25 May 2020 01:05:37 +0100 [thread overview]
Message-ID: <20200525000537.GB23230@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20200524233942.8702-3-sargun@sargun.me>
On Sun, May 24, 2020 at 04:39:39PM -0700, Sargun Dhillon wrote:
> +static void seccomp_handle_addfd(struct seccomp_kaddfd *addfd)
> +{
> + int ret;
> +
> + /*
> + * Remove the notification, and reset the list pointers, indicating
> + * that it has been handled.
> + */
> + list_del_init(&addfd->list);
> +
> + ret = security_file_receive(addfd->file);
> + if (ret)
> + goto out;
> +
> + if (addfd->fd >= 0) {
> + ret = replace_fd(addfd->fd, addfd->file, addfd->flags);
> + if (ret >= 0)
> + fput(addfd->file);
> + } else {
> + ret = get_unused_fd_flags(addfd->flags);
> + if (ret >= 0)
> + fd_install(ret, addfd->file);
Bad refcounting rules. *IF* we go with anything of that sort (and I'm not
convinced that the entire series makes sense), it's better to have more
uniform rules re reference consumption/disposal.
Make the destructor of addfd *ALWAYS* drop its reference. And have this
function go
if (addfd->fd >= 0) {
ret = replace_fd(addfd->fd, addfd->file, addfd->flags);
} else {
ret = get_unused_fd_flags(addfd->flags);
if (ret >= 0)
fd_install(ret, get_file(addfd->file));
}
next prev parent reply other threads:[~2020-05-25 0:05 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-24 23:39 [PATCH 0/5] Add seccomp notifier ioctl that enables adding fds Sargun Dhillon
2020-05-24 23:39 ` [PATCH 1/5] seccomp: Add find_notification helper Sargun Dhillon
2020-05-24 23:55 ` Tycho Andersen
2020-05-25 13:26 ` Christian Brauner
2020-05-24 23:39 ` [PATCH 2/5] seccomp: Introduce addfd ioctl to seccomp user notifier Sargun Dhillon
2020-05-24 23:57 ` Tycho Andersen
2020-05-24 23:58 ` Tycho Andersen
2020-05-25 0:05 ` Al Viro [this message]
2020-05-25 0:27 ` Sargun Dhillon
2020-05-25 0:39 ` Al Viro
2020-05-25 13:50 ` Christian Brauner
2020-05-26 6:59 ` Sargun Dhillon
2020-05-26 8:22 ` Christian Brauner
2020-05-24 23:39 ` [PATCH 3/5] selftests/seccomp: Test SECCOMP_IOCTL_NOTIF_ADDFD Sargun Dhillon
2020-05-24 23:39 ` [PATCH 4/5] seccomp: Add SECCOMP_ADDFD_FLAG_MOVE flag to add fd ioctl Sargun Dhillon
2020-05-25 14:20 ` Christian Brauner
2020-05-26 6:08 ` Sargun Dhillon
2020-05-24 23:39 ` [PATCH 5/5] selftests/seccomp: Add test for addfd move semantics Sargun Dhillon
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