From: Sargun Dhillon <sargun@sargun.me>
To: Kees Cook <keescook@chromium.org>
Cc: Christian Brauner <christian.brauner@ubuntu.com>,
containers@lists.linux-foundation.org,
Giuseppe Scrivano <gscrivan@redhat.com>,
Robert Sesek <rsesek@google.com>,
Chris Palmer <palmer@google.com>, Jann Horn <jannh@google.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Daniel Wagner <daniel.wagner@bmw-carit.de>,
linux-kernel@vger.kernel.org, Matt Denton <mpdenton@google.com>,
John Fastabend <john.r.fastabend@intel.com>,
linux-fsdevel@vger.kernel.org, Tejun Heo <tj@kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>,
cgroups@vger.kernel.org, stable@vger.kernel.org,
"David S . Miller" <davem@davemloft.net>
Subject: Re: [PATCH v3 1/4] fs, net: Standardize on file_receive helper to move fds across processes
Date: Thu, 11 Jun 2020 04:41:02 +0000 [thread overview]
Message-ID: <20200611044101.GA5909@ircssh-2.c.rugged-nimbus-611.internal> (raw)
In-Reply-To: <202006101953.899EFB53@keescook>
On Wed, Jun 10, 2020 at 07:59:55PM -0700, Kees Cook wrote:
>
> Yeah, that seems reasonable. Here's the diff for that part:
>
> diff --git a/include/uapi/linux/seccomp.h b/include/uapi/linux/seccomp.h
> index 7b6028b399d8..98bf19b4e086 100644
> --- a/include/uapi/linux/seccomp.h
> +++ b/include/uapi/linux/seccomp.h
> @@ -118,7 +118,6 @@ struct seccomp_notif_resp {
>
> /**
> * struct seccomp_notif_addfd
> - * @size: The size of the seccomp_notif_addfd datastructure
> * @id: The ID of the seccomp notification
> * @flags: SECCOMP_ADDFD_FLAG_*
> * @srcfd: The local fd number
> @@ -126,7 +125,6 @@ struct seccomp_notif_resp {
> * @newfd_flags: The O_* flags the remote FD should have applied
> */
> struct seccomp_notif_addfd {
> - __u64 size;
> __u64 id;
> __u32 flags;
> __u32 srcfd;
> diff --git a/kernel/seccomp.c b/kernel/seccomp.c
> index 3c913f3b8451..00cbdad6c480 100644
> --- a/kernel/seccomp.c
> +++ b/kernel/seccomp.c
> @@ -1297,14 +1297,9 @@ static long seccomp_notify_addfd(struct seccomp_filter *filter,
> struct seccomp_notif_addfd addfd;
> struct seccomp_knotif *knotif;
> struct seccomp_kaddfd kaddfd;
> - u64 size;
> int ret;
>
> - ret = get_user(size, &uaddfd->size);
> - if (ret)
> - return ret;
> -
> - ret = copy_struct_from_user(&addfd, sizeof(addfd), uaddfd, size);
> + ret = copy_from_user(&addfd, uaddfd, sizeof(addfd));
> if (ret)
> return ret;
>
>
Looks good to me. If we ever change the size of this struct, we can do the work
then to copy_struct_from_user.
> >
> > ----
> > +#define SECCOMP_IOCTL_NOTIF_ADDFD SECCOMP_IOR(3, \
> > + struct seccomp_notif_addfd)
> >
> > Lastly, what I believe to be a small mistake, it should be SECCOMP_IOW, based on
> > the documentation in ioctl.h -- "_IOW means userland is writing and kernel is
> > reading."
>
> Oooooh. Yeah; good catch. Uhm, that means SECCOMP_IOCTL_NOTIF_ID_VALID
> is wrong too, yes? Tycho, Christian, how disruptive would this be to
> fix? (Perhaps support both and deprecate the IOR version at some point
> in the future?)
I think at a minimum we should change the uapi, and accept both (for now). Maybe
a pr_warn_once telling people not to use the old one.
I can do the patch, if you want.
>
> Diff for just addfd's change:
>
> diff --git a/include/uapi/linux/seccomp.h b/include/uapi/linux/seccomp.h
> index 7b6028b399d8..98bf19b4e086 100644
> --- a/include/uapi/linux/seccomp.h
> +++ b/include/uapi/linux/seccomp.h
> @@ -146,7 +144,7 @@ struct seccomp_notif_addfd {
> struct seccomp_notif_resp)
> #define SECCOMP_IOCTL_NOTIF_ID_VALID SECCOMP_IOR(2, __u64)
> /* On success, the return value is the remote process's added fd number */
> -#define SECCOMP_IOCTL_NOTIF_ADDFD SECCOMP_IOR(3, \
> +#define SECCOMP_IOCTL_NOTIF_ADDFD SECCOMP_IOW(3, \
> struct seccomp_notif_addfd)
>
> #endif /* _UAPI_LINUX_SECCOMP_H */
>
> --
> Kees Cook
Looks good. Thank you.
next prev parent reply other threads:[~2020-06-11 4:41 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200603011044.7972-1-sargun@sargun.me>
2020-06-03 1:10 ` [PATCH v3 1/4] fs, net: Standardize on file_receive helper to move fds across processes Sargun Dhillon
2020-06-04 1:24 ` Christian Brauner
2020-06-04 2:22 ` Kees Cook
2020-06-04 5:20 ` Sargun Dhillon
2020-06-04 12:52 ` Christian Brauner
2020-06-04 13:28 ` David Laight
2020-06-05 7:54 ` Sargun Dhillon
2020-06-09 19:43 ` Kees Cook
2020-06-09 20:03 ` Christian Brauner
2020-06-09 20:55 ` Kees Cook
2020-06-09 21:27 ` Christian Brauner
2020-06-10 5:27 ` Kees Cook
2020-06-10 8:12 ` Sargun Dhillon
2020-06-10 8:48 ` David Laight
2020-06-11 3:02 ` Kees Cook
2020-06-11 7:51 ` David Laight
2020-06-10 17:10 ` Kees Cook
2020-06-11 2:59 ` Kees Cook
2020-06-11 4:41 ` Sargun Dhillon [this message]
2020-06-11 9:19 ` Christian Brauner
2020-06-11 10:39 ` Sargun Dhillon
2020-06-11 23:23 ` Kees Cook
2020-06-11 10:01 ` Christian Brauner
2020-06-11 11:06 ` Sargun Dhillon
2020-06-11 14:42 ` Christian Brauner
2020-06-11 14:56 ` David Laight
2020-06-11 23:49 ` Kees Cook
2020-06-12 6:58 ` Kees Cook
2020-06-12 8:36 ` David Laight
2020-06-12 10:46 ` Sargun Dhillon
2020-06-12 15:13 ` Kees Cook
2020-06-12 15:55 ` David Laight
2020-06-12 18:28 ` Christian Brauner
2020-06-12 18:38 ` Kees Cook
2020-06-12 18:42 ` Christian Brauner
2020-06-15 8:27 ` David Laight
2020-06-10 9:30 ` Christian Brauner
2020-06-04 3:39 ` Sargun Dhillon
2020-06-03 1:10 ` [PATCH v3 2/4] pid: Use file_receive helper to copy FDs Sargun Dhillon
2020-06-03 1:10 ` [PATCH v3 3/4] seccomp: Introduce addfd ioctl to seccomp user notifier Sargun Dhillon
2020-06-03 1:10 ` [PATCH v3 4/4] selftests/seccomp: Test SECCOMP_IOCTL_NOTIF_ADDFD Sargun Dhillon
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