On Wed, Jul 09, 2025 at 10:00:56AM +0200, Maxime Bélair wrote:
> 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 Bélair <maxime.belair@xxxxxxxxxxxxx>
> ---
> security/apparmor/apparmorfs.c | 31 ++++++++++
> security/apparmor/include/apparmor.h | 4 ++
> security/apparmor/include/apparmorfs.h | 3 +
> security/apparmor/lsm.c | 84 ++++++++++++++++++++++++++
> 4 files changed, 122 insertions(+)
>
> diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
> index 9b6c2f157f83..0ce40290f44e 100644
> --- a/security/apparmor/lsm.c
> +++ b/security/apparmor/lsm.c
> @@ -1275,6 +1275,86 @@ static int apparmor_socket_shutdown(struct socket *sock, int how)
> return aa_sock_perm(OP_SHUTDOWN, AA_MAY_SHUTDOWN, sock);
> }
>
> +/**
> + * 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 != LSM_POLICY_LOAD || flags)
> + return -EOPNOTSUPP;
> + if (size == 0)
> + return -EINVAL;
> + if (size > AA_PROFILE_NAME_MAX_SIZE)
> + return -E2BIG;
> +
> + name = kmalloc(size, GFP_KERNEL);
> + if (!name)
> + return -ENOMEM;
This hunk should be part of the syscall code and shared amongst LSMs.
> +
> +
> + name_size = strncpy_from_user(name, buf, size);
> + if (name_size < 0) {
> + kfree(name);
> + return name_size;
> + }
> +
> + ret = aa_change_profile(name, AA_CHANGE_STACK);
> +
> + kfree(name);
> +
> + return ret;
> +}
