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s=20210705; t=1746688381; bh=YQhnn+kRn85AxiqKoin5sojaq0xB+1V3eXIEwuwJYFE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=OU6BkEnni+yO4T8h3ZetVYvIywFircaRxnJJDhR4CI6B+a7piARIhadYvF3RzbZUR enMidxv6+1t1rQHwW82CWHomHVjbwuOVjfb7VGMmo2hqnbieT0Iu557AFC1YkVNd1V BaBYjzGQzJ41Li+WCND8yj+gFPOMhNnCyOoz3CNn616oyBdGoJCy3aAb70qsxoa7E7 yUizlTDEs06qImwOFLdptH+ZmLvyTjmczuPpMRjgQEWH6DPDoTnGQ39YPiTd9o2xGD ifXRNaTVWdgZWlH5eaV3Lk+rA6ca17+xg4b2L38LP+93bEPdcZSxQKNMyLyTV1HBHm SSjAm4GB/R85g== Message-ID: <48b5512b-5e38-405a-80e7-64be43bf04e8@canonical.com> Date: Thu, 8 May 2025 00:12:58 -0700 Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/3] Wire up the lsm_manage_policy syscall To: Song Liu , =?UTF-8?Q?Maxime_B=C3=A9lair?= Cc: linux-security-module@vger.kernel.org, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, mic@digikod.net, kees@kernel.org, stephen.smalley.work@gmail.com, casey@schaufler-ca.com, takedakn@nttdata.co.jp, penguin-kernel@i-love.sakura.ne.jp, linux-api@vger.kernel.org, apparmor@lists.ubuntu.com, linux-kernel@vger.kernel.org References: <20250506143254.718647-1-maxime.belair@canonical.com> <20250506143254.718647-2-maxime.belair@canonical.com> Content-Language: en-US From: John Johansen Autocrypt: addr=john.johansen@canonical.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit On 5/6/25 23:26, Song Liu wrote: > On Tue, May 6, 2025 at 7:40 AM Maxime Bélair > wrote: >> >> Add support for the new lsm_manage_policy syscall, providing a unified >> API for loading and modifying LSM policies without requiring the LSM’s >> pseudo-filesystem. >> >> Benefits: >> - Works even if the LSM pseudo-filesystem isn’t mounted or available >> (e.g. in containers) >> - Offers a logical and unified interface rather than multiple >> heterogeneous pseudo-filesystems. > > These two do not feel like real benefits: > - Not working in containers is often not an issue, but a feature. and the LSM doesn't have to allow the syscall to function in a container where appropriate. Its up to the LSM if the syscall is supported and what kind of permissions are needed. However having the ability to function in a container and not having to mount securityfs, or procfs into a container. similar to what landlock gets with its syscall can be beneficial. > - One syscall cannot fit all use cases well... > of course not, and for those other use cases new syscalls can be added. >> - Avoids overhead of other kernel interfaces for better efficiency > > .. and it is is probably less efficient, because everything need to > fit in the same API. > no not everything, just what fits into the syscall. Nor does an LSM have to use the syscall it is still use what works for it. This could be a little more efficient than the current fs interface used by apparmor/selinux/smack but I don't think efficiency is going to be a huge win for this. > Overall, this set doesn't feel like a good change to me. > > Thanks, > Song