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s=20210705; t=1746692720; bh=R+HBIELU/mr5etBwZZ2ZwuOSlSkfomUQCsQIiupH+I8=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Dw9J3hY0wd5U1CH2nIUbymXPKnrL7FajpGovL4rEzxlpiA536TVbqZ4ZdsN2l7ilY 1X5gls5IFTqCPTrE+p5Zycrj6lJgHyJgBf9/Tisn0T7QAm3EiNNtA++aP6abBIxAeY GT9LmPwIcoAosNidYhL9g402ixiu3ylurfzf5ISaxEDe6Okngf/fRd22sw3zu2JWuF O/AZ9fFA/aEXPTIlX6Oa3uDPrtlNPU9dNkDY2wND+fN9sshqXow528GWdrpIlsApHJ PZK/M4PY8DDeBUL5NuRarFLi3nnljfC7koWCYZ0K57zi8iOe0rLJ4UVKg2gXkkOwNX S4TsgxOqddiww== Message-ID: <6d785712-6d8e-491c-86d4-1cbe5895778f@canonical.com> Date: Thu, 8 May 2025 01:25:19 -0700 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/3] lsm: introduce security_lsm_manage_policy hook To: Tetsuo Handa , =?UTF-8?Q?Maxime_B=C3=A9lair?= , linux-security-module@vger.kernel.org Cc: 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, linux-api@vger.kernel.org, apparmor@lists.ubuntu.com, linux-kernel@vger.kernel.org References: <20250506143254.718647-1-maxime.belair@canonical.com> <20250506143254.718647-3-maxime.belair@canonical.com> <9c68743f-5efa-4a77-a29b-d3e8f2b2a462@I-love.SAKURA.ne.jp> 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 5/7/25 03:40, Tetsuo Handa wrote: > On 2025/05/06 23:32, Maxime Bélair wrote: >> diff --git a/security/lsm_syscalls.c b/security/lsm_syscalls.c >> index dcaad8818679..b39e6635a7d5 100644 >> --- a/security/lsm_syscalls.c >> +++ b/security/lsm_syscalls.c >> @@ -122,5 +122,10 @@ SYSCALL_DEFINE3(lsm_list_modules, u64 __user *, ids, u32 __user *, size, >> SYSCALL_DEFINE5(lsm_manage_policy, u32, lsm_id, u32, op, void __user *, buf, u32 >> __user *, size, u32, flags) >> { >> - return 0; >> + size_t usize; >> + >> + if (get_user(usize, size)) >> + return -EFAULT; >> + >> + return security_lsm_manage_policy(lsm_id, op, buf, usize, flags); >> } > > syzbot will report user-controlled unbounded huge size memory allocation attempt. ;-) > > This interface might be fine for AppArmor, but TOMOYO won't use this interface because > TOMOYO's policy is line-oriented ASCII text data where the destination is switched via > pseudo‑filesystem's filename; use of filename helps restricting which type of policy > can be manipulated by which process. > That is fine. But curious I am curious what the interface would look like to fit TOMOYO's needs. I look at the current implementation as an opening discussion of what the syscall should look like. I have no delusions that we are going to get something that will fit all LSMs but without requirements, we won't be able to even attempt to hash something better out.