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(176-136-128-80.abo.bbox.fr [176.136.128.80]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-canonical-1.canonical.com (Postfix) with ESMTPSA id 01BB441260; Tue, 1 Jul 2025 09:20:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical.com; s=20210705; t=1751361612; bh=UxW42upBEQMGjVGIBlOTFGoX6HXLadq+Li0fl5+hEPI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=LhfzDPB3E2dWMzt+jZT3n8qYbI84Mz9VGCecgZCAaukn+aGlRBaNABr0iChOOfx8b 0YpSPkvGEohh24Zs/TguNtowklmWOMMZtR8VwCw83Kl4ceJZKPQY/HsYsp0jW+AoGU xnZWXqk3B2V5m1sMwU7cqyFN1udqWVSAX5ciAqGHwYi6tmVWhRCAg0RsO/VVGY8Qmd OZGLMZTEfd7yoiq5MWOsamOeWpn/klh6JzxZYdIZRBnL2AgwlonAV6BHscPF8kescN njeGY72eXaL0/1+e9JNZZSh77l8PiBgVqy1XZ2CSHjqCXGUsbpoSPjHsepDHi7LnlR L1dTXBoroUoNw== From: =?UTF-8?q?Maxime=20B=C3=A9lair?= To: linux-security-module@vger.kernel.org Cc: 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, song@kernel.org, rdunlap@infradead.org, linux-api@vger.kernel.org, apparmor@lists.ubuntu.com, linux-kernel@vger.kernel.org, =?UTF-8?q?Maxime=20B=C3=A9lair?= Subject: [PATCH v4 3/3] AppArmor: add support for lsm_config_self_policy and lsm_config_system_policy Date: Tue, 1 Jul 2025 11:17:41 +0200 Message-ID: <20250701091904.395837-4-maxime.belair@canonical.com> X-Mailer: git-send-email 2.48.1 In-Reply-To: <20250701091904.395837-1-maxime.belair@canonical.com> References: <20250701091904.395837-1-maxime.belair@canonical.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Enable users to manage AppArmor policies through the new hooks lsm_config_self_policy and lsm_config_system_policy. lsm_config_self_policy allows stacking existing policies in the kernel. This ensures that it can only further restrict the caller and can never be used to gain new privileges. lsm_config_system_policy allows loading or replacing AppArmor policies in any AppArmor namespace. Signed-off-by: Maxime B=C3=A9lair --- security/apparmor/apparmorfs.c | 31 ++++++++++ security/apparmor/include/apparmor.h | 4 ++ security/apparmor/include/apparmorfs.h | 3 + security/apparmor/lsm.c | 79 ++++++++++++++++++++++++++ 4 files changed, 117 insertions(+) diff --git a/security/apparmor/apparmorfs.c b/security/apparmor/apparmorfs.c index 6039afae4bfc..6df43299b045 100644 --- a/security/apparmor/apparmorfs.c +++ b/security/apparmor/apparmorfs.c @@ -439,6 +439,37 @@ static ssize_t policy_update(u32 mask, const char __us= er *buf, size_t size, return error; } =20 +/** + * aa_profile_load_ns_name - load a profile into the current namespace ide= ntified by name + * @name: The name of the namesapce to load the policy in. "" for root_ns + * @name_size: size of @name. 0 For root ns + * @buf: buffer containing the user-provided policy + * @size: size of @buf + * @ppos: position pointer in the file + * + * Returns: 0 on success, negative value on error + */ +ssize_t aa_profile_load_ns_name(char *name, size_t name_size, const void _= _user *buf, + size_t size, loff_t *ppos) +{ + struct aa_ns *ns; + + if (name_size =3D=3D 0) + ns =3D aa_get_ns(root_ns); + else + ns =3D aa_lookupn_ns(root_ns, name, name_size); + + if (!ns) + return -EINVAL; + + int error =3D policy_update(AA_MAY_LOAD_POLICY | AA_MAY_REPLACE_POLICY, + buf, size, ppos, ns); + + aa_put_ns(ns); + + return error >=3D 0 ? 0 : error; +} + /* .load file hook fn to load policy */ static ssize_t profile_load(struct file *f, const char __user *buf, size_t= size, loff_t *pos) diff --git a/security/apparmor/include/apparmor.h b/security/apparmor/inclu= de/apparmor.h index f83934913b0f..1d9a2881a8b9 100644 --- a/security/apparmor/include/apparmor.h +++ b/security/apparmor/include/apparmor.h @@ -62,5 +62,9 @@ extern unsigned int aa_g_path_max; #define AA_DEFAULT_CLEVEL 0 #endif /* CONFIG_SECURITY_APPARMOR_EXPORT_BINARY */ =20 +/* Syscall-related buffer size limits */ + +#define AA_PROFILE_NAME_MAX_SIZE (1 << 9) +#define AA_PROFILE_MAX_SIZE (1 << 28) =20 #endif /* __APPARMOR_H */ diff --git a/security/apparmor/include/apparmorfs.h b/security/apparmor/inc= lude/apparmorfs.h index 1e94904f68d9..fd415afb7659 100644 --- a/security/apparmor/include/apparmorfs.h +++ b/security/apparmor/include/apparmorfs.h @@ -112,6 +112,9 @@ int __aafs_profile_mkdir(struct aa_profile *profile, st= ruct dentry *parent); void __aafs_ns_rmdir(struct aa_ns *ns); int __aafs_ns_mkdir(struct aa_ns *ns, struct dentry *parent, const char *n= ame, struct dentry *dent); +ssize_t aa_profile_load_ns_name(char *name, size_t name_len, const void __= user *buf, + size_t size, loff_t *ppos); + =20 struct aa_loaddata; =20 diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c index 9b6c2f157f83..1b7b5381f478 100644 --- a/security/apparmor/lsm.c +++ b/security/apparmor/lsm.c @@ -1275,6 +1275,81 @@ static int apparmor_socket_shutdown(struct socket *s= ock, int how) return aa_sock_perm(OP_SHUTDOWN, AA_MAY_SHUTDOWN, sock); } =20 +/** + * apparmor_lsm_config_self_policy - Stack a profile + * @lsm_id: AppArmor ID (LSM_ID_APPARMOR). Unused here + * @op: operation to perform. Currently, only LSM_POLICY_LOAD is supported + * @buf: buffer containing the user-provided name of the profile to stack + * @size: size of @buf + * @flags: reserved for future use; must be zero + * + * Returns: 0 on success, negative value on error + */ +static int apparmor_lsm_config_self_policy(u32 lsm_id, u32 op, void __user= *buf, + size_t size, u32 flags) +{ + char *name; + long name_size; + int ret; + + if (op !=3D LSM_POLICY_LOAD || flags) + return -EOPNOTSUPP; + if (size > AA_PROFILE_NAME_MAX_SIZE) + return -E2BIG; + + name =3D kmalloc(size, GFP_KERNEL); + if (!name) + return -ENOMEM; + + + name_size =3D strncpy_from_user(name, buf, size); + if (name_size < 0) { + kfree(name); + return name_size; + } + + ret =3D aa_change_profile(name, AA_CHANGE_STACK); + + kfree(name); + + return ret; +} + +/** + * apparmor_lsm_config_system_policy - Load or replace a system policy + * @lsm_id: AppArmor ID (LSM_ID_APPARMOR). Unused here + * @op: operation to perform. Currently, only LSM_POLICY_LOAD is supported + * @buf: user-supplied buffer in the form "\0" + * is the namespace to load the policy into (empty string for = root) + * is the policy to load + * @size: size of @buf + * @flags: reserved for future uses; must be zero + * + * Returns: 0 on success, negative value on error + */ +static int apparmor_lsm_config_system_policy(u32 lsm_id, u32 op, void __us= er *buf, + size_t size, u32 flags) +{ + loff_t pos =3D 0; // Partial writing is not currently supported + char name[AA_PROFILE_NAME_MAX_SIZE]; + long name_size; + + if (op !=3D LSM_POLICY_LOAD || flags) + return -EOPNOTSUPP; + if (size > AA_PROFILE_MAX_SIZE) + return -E2BIG; + + name_size =3D strncpy_from_user(name, buf, AA_PROFILE_NAME_MAX_SIZE); + if (name_size < 0) + return name_size; + else if (name_size =3D=3D AA_PROFILE_NAME_MAX_SIZE) + return -E2BIG; + + return aa_profile_load_ns_name(name, name_size, buf + name_size + 1, + size - name_size - 1, &pos); +} + + #ifdef CONFIG_NETWORK_SECMARK /** * apparmor_socket_sock_rcv_skb - check perms before associating skb to sk @@ -1483,6 +1558,10 @@ static struct security_hook_list apparmor_hooks[] __= ro_after_init =3D { LSM_HOOK_INIT(socket_getsockopt, apparmor_socket_getsockopt), LSM_HOOK_INIT(socket_setsockopt, apparmor_socket_setsockopt), LSM_HOOK_INIT(socket_shutdown, apparmor_socket_shutdown), + + LSM_HOOK_INIT(lsm_config_self_policy, apparmor_lsm_config_self_policy), + LSM_HOOK_INIT(lsm_config_system_policy, + apparmor_lsm_config_system_policy), #ifdef CONFIG_NETWORK_SECMARK LSM_HOOK_INIT(socket_sock_rcv_skb, apparmor_socket_sock_rcv_skb), #endif --=20 2.48.1