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Date:   Sun, 24 May 2020 17:55:25 -0600
From:   Tycho Andersen <tycho@tycho.ws>
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, 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 1/5] seccomp: Add find_notification helper
Message-ID: <20200524235525.GH2605652@cisco>
References: <20200524233942.8702-1-sargun@sargun.me>
 <20200524233942.8702-2-sargun@sargun.me>
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On Sun, May 24, 2020 at 04:39:38PM -0700, Sargun Dhillon wrote:
> This adds a helper which can iterate through a seccomp_filter to
> find a notification matching an ID. It removes several replicated
> chunks of code.
> 
> Signed-off-by: Sargun Dhillon <sargun@sargun.me>
> Cc: Matt Denton <mpdenton@google.com>
> Cc: Kees Cook <keescook@google.com>,
> Cc: Jann Horn <jannh@google.com>,
> Cc: Robert Sesek <rsesek@google.com>,
> Cc: Chris Palmer <palmer@google.com>
> Cc: Christian Brauner <christian.brauner@ubuntu.com>
> Cc: Tycho Andersen <tycho@tycho.ws>
> ---
>  kernel/seccomp.c | 38 +++++++++++++++++++++-----------------
>  1 file changed, 21 insertions(+), 17 deletions(-)
> 
> diff --git a/kernel/seccomp.c b/kernel/seccomp.c
> index 55a6184f5990..f6ce94b7a167 100644
> --- a/kernel/seccomp.c
> +++ b/kernel/seccomp.c
> @@ -1021,10 +1021,25 @@ static int seccomp_notify_release(struct inode *inode, struct file *file)
>  	return 0;
>  }
>  
> +/* must be called with notif_lock held */
> +static inline struct seccomp_knotif *
> +find_notification(struct seccomp_filter *filter, u64 id)
> +{
> +	struct seccomp_knotif *cur;
> +
> +	list_for_each_entry(cur, &filter->notif->notifications, list) {
> +		if (cur->id == id)
> +			return cur;
> +	}
> +
> +	return NULL;
> +}

I think there's also an instance of this in _send() that we can change
to use find_notification() as well.

Tycho