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([2001:861:3280:410:2ef0:5dff:fe60:6274]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-ad1891ef1e0sm923525466b.77.2025.05.07.08.37.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 07 May 2025 08:37:26 -0700 (PDT) Message-ID: Date: Wed, 7 May 2025 17:37:25 +0200 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: Song Liu Cc: linux-security-module@vger.kernel.org, john.johansen@canonical.com, 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> <20250506143254.718647-3-maxime.belair@canonical.com> Content-Language: en-US From: =?UTF-8?Q?Maxime_B=C3=A9lair?= Autocrypt: addr=maxime.belair@canonical.com; keydata= xsDNBGWdWVYBDADTTxrLrewr4UPUa9CvBTsQFOLNM1D8rvhDyf0UWHD0Z3EuqePliDUpQ1FQ EaDAd1qEmsf4ybF8dWN37OC25iBmolZv+tzpRmlhTQtyBu/xWu5LwWIpLFhQq+9AkcHa4Za8 2/ovK84K9u8RPN6Y9h/UOzAS23UI86T58KxzDHEHbRC5XA5VmOgcX71FQDalvMUaAHJV/WRe OifBAwPbapTmTuKEmuLXvDczKqAADKWHXi7JECpY+1Mpd9xRd9dWu7ooKQ+KmOFOZcOxKagY 9+qK77wUzgDleDU8ihuzOWol+K5vZg0saiRJQm8l9mhIXrREloiUntScBraHBSqSy0kMuIK7 bmIflfgDarYVXV5rxotIWu0guyn8kT/N+DKghi52/VbDdOBngwYLTBO3sZtIdw0pkhkwHDcl se+BThNz6xC0UXlSZrUBQ5RBruBSTXZHwZM9Oyhlf+S1EtZe2jO1R2hSZ0rrHJ/93LT5ARFd jGInAz6ocW0He8FB5nGjfQcAEQEAAc0sTWF4aW1lIELDqWxhaXIgPG1heGltZS5iZWxhaXJA Y2Fub25pY2FsLmNvbT7CwQ4EEwEKADgWIQTKdrj/a+71WSW+OmUnvE/6RFk5uAUCZZ1ZVgIb AwULCQgHAgYVCgkICwIEFgIDAQIeAQIXgAAKCRAnvE/6RFk5uL/BC/98c45dc+GgTCgYO8YY lXJ/N9+QZyw5n4CBcXphBkd/xZkwlOgJ4bY5zHH3ukKBfuNB77RLRT+mzHwnCELXRqQOebtN ZhI2JDvdAwemyxsstj1lSadYhlRDjxLmphARRbiJ9q8g3MMhv/zLcM5ObFfSP4lQaxaiSEjw pAJNLR7d9rsMUYi/lWxQKDcjGaKnQkq5qDtLzoWw6pIf2VKGQDbibPdVTiedByIbF6x21LEQ rVNHTOnqoqC2X6JiSWz4pCuYRQM7bY1BW0ZUOWnshJNQqi8+4/A/h+Yss3vXp82+oKRw7Dls /B5MjR4yHdCBb8RWM0y0kghpvjMmp5Nbsh5XaDu2yv5qkxs4NHoklalUvBy34O2lx0ITVSGN pbzw93cUZtomDRtXder0cY6FPVNrN8aP6PljoYrobVDCb451nc1YrFEiMUG8jCfD85JpwK+S Ql9RccaMFTcPXe0rFWr7ecwjEtxDd6/Mu9tpW1mLMOKF5TJxrmVtbAIauPgKp0rOwM0EZZ1Z VgEMANEV0CsOdJHC9VROvdooRgl8Q7E19QdsCpDD1rziS1KeegSPo5n1uDsXoW88Rdpxqap0 fcgECJxZfH4bgHr0G/pWHbbltfM7jdvdW+cXD/8wVBgzZrbysPa9WpaM/S/DXj2qVIng3O43 izSedJ81iYyvi7i2e4YtZndGsz8DslaUDqBCHKvG5ydp/9W0Wj55SxYCmt1rdv5GUYULoVhI uevY8olct38tl7rSZxBpzez3rK3WCQkSN1uf8zzluDLWXEmJjafJfzO5YC6s+ScZ7kXEIcJC ttGXwVJWJF+Yq7EKaGoEMK+5e4SJgok6vrx3f+lKa3R70jqwAj1ulsvS3LRgrjtN8dhIuJdE aSNTkEO5TvrHzcDk/v5X7Tn7YOo4qheqC4k+PzNBI/Y4TGY6FJFskaii89wRVmSg3meRv9p4 kT2XXtNueH/CWtwvSK3f+2u21DbNnknjSXg0lNlO380NwN1Q0BnDTPcASENd5T4gwxBw5GED H6yK2jn5bFMUxwARAQABwsD2BBgBCgAgFiEEyna4/2vu9VklvjplJ7xP+kRZObgFAmWdWVYC GwwACgkQJ7xP+kRZObiqjQwAlD/IBOVIkpuGjO7LoxpA8qe63AO1HygvGVOlFHLrw4ap+edK bUpmEzht20VQNtzyosBbXYDDrcFiSiTNoBKFYx7ekfQ+OwxzU0wOkUJ2m56EKAlUHotwnHm+ s1FF7SFQO7oubKCZPSjPgex8XmY43uZXnKmsoFC0iJdB6a8wOPIk10VpaEfgrGdwUPeDchAX ZSAEPZRM0C2JDjghdIlVek0goTWh4RARJ/Mz73K0VZoqxecSArSglOqlpUO2YETJGB8kR6Ip uk605mf+aJoQq/8DtoYOTFFaTViKlKgVoNi0e1il6HkEhASyGQeQZkcq92O6ndDm//csiJT2 oRAG5XUu5Q1PWG0oY4cZ6XN1z8nkj5Mj23SRhBwVjh2PY2p4cyFRTBrBDaNV38LHw6tVjdhk 8YNqGOVqceueWdZmWbp8b88a0wzOcrPAvcxJ14FhMyMO9P7FblDYLNYr0oAYj+UyhxOPbRZz yriCIKEAbLqHTyj+RhbroZmv5q3X7iVq In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 5/7/25 08:19, Song Liu wrote: > On Tue, May 6, 2025 at 7:40 AM Maxime Bélair > wrote: >> >> Define a new LSM hook security_lsm_manage_policy and wire it into the >> lsm_manage_policy() syscall so that LSMs can register a unified interface >> for policy management. This initial, minimal implementation only supports >> the LSM_POLICY_LOAD operation to limit changes. >> >> Signed-off-by: Maxime Bélair > [...] >> diff --git a/security/security.c b/security/security.c >> index fb57e8fddd91..256104e338b1 100644 >> --- a/security/security.c >> +++ b/security/security.c >> @@ -5883,6 +5883,27 @@ int security_bdev_setintegrity(struct block_device *bdev, >> } >> EXPORT_SYMBOL(security_bdev_setintegrity); >> >> +/** >> + * security_lsm_manage_policy() - Manage the policies of LSMs >> + * @lsm_id: id of the lsm to target >> + * @op: Operation to perform (one of the LSM_POLICY_XXX values) >> + * @buf: userspace pointer to policy data >> + * @size: size of @buf >> + * @flags: lsm policy management flags >> + * >> + * Manage the policies of a LSM. This notably allows to update them even when >> + * the lsmfs is unavailable is restricted. Currently, only LSM_POLICY_LOAD is >> + * supported. >> + * >> + * Return: Returns 0 on success, error on failure. >> + */ >> +int security_lsm_manage_policy(u32 lsm_id, u32 op, void __user *buf, >> + size_t size, u32 flags) >> +{ >> + return call_int_hook(lsm_manage_policy, lsm_id, op, buf, size, flags); > > If the LSM doesn't implement this hook, sys_lsm_manage_policy will return 0 > for any inputs, right? This is gonna be so confusing for users. Indeed, that was an oversight. It will return -EOPNOTSUPP in the next patch revision. > > Thanks, > Song Thanks, Maxime