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Date:   Thu, 9 Jan 2020 05:21:49 +1100 (AEDT)
From:   James Morris <jmorris@namei.org>
To:     KP Singh <kpsingh@chromium.org>
cc:     linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
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Subject: Re: [PATCH bpf-next v1 10/13] bpf: lsm: Handle attachment of the
 same program
In-Reply-To: <20191220154208.15895-11-kpsingh@chromium.org>
Message-ID: <alpine.LRH.2.21.2001090521340.9683@namei.org>
References: <20191220154208.15895-1-kpsingh@chromium.org> <20191220154208.15895-11-kpsingh@chromium.org>
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On Fri, 20 Dec 2019, KP Singh wrote:

> From: KP Singh <kpsingh@google.com>
> 
> Allow userspace to attach a newer version of a program without having
> duplicates of the same program.
> 
> If BPF_F_ALLOW_OVERRIDE is passed, the attachment logic compares the
> name of the new program to the names of existing attached programs. The
> names are only compared till a "__" (or '\0', if there is no "__"). If
> a successful match is found, the existing program is replaced with the
> newer attachment.
> 
> ./loader Attaches "env_dumper__v1" followed by "env_dumper__v2"
> to the bprm_check_security hook..
> 
> ./loader
> ./loader
> 
> Before:
> 
>   cat /sys/kernel/security/bpf/process_execution
>   env_dumper__v1
>   env_dumper__v2
> 
> After:
> 
>   cat /sys/kernel/security/bpf/process_execution
>   env_dumper__v2
> 
> Signed-off-by: KP Singh <kpsingh@google.com>


Reviewed-by: James Morris <jamorris@linux.microsoft.com>


-- 
James Morris
<jmorris@namei.org>