Re: [PATCH v4 01/13] LSM: Add the lsm_prop data structure.

[John Johansen]

On 10/9/24 10:32, Casey Schaufler wrote:
> When more than one security module is exporting data to audit and
> networking sub-systems a single 32 bit integer is no longer
> sufficient to represent the data. Add a structure to be used instead.
>
> The lsm_prop structure definition is intended to keep the LSM
> specific information private to the individual security modules.
> The module specific information is included in a new set of
> header files under include/lsm. Each security module is allowed
> to define the information included for its use in the lsm_prop.
> SELinux includes a u32 secid. Smack includes a pointer into its
> global label list. The conditional compilation based on feature
> inclusion is contained in the include/lsm files.
>
> Suggested-by: Paul Moore <paul@xxxxxxxxxxxxxx>
> Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>

Acked-by: John Johansen <john.johansen@xxxxxxxxxxxxx>

> Cc: apparmor@xxxxxxxxxxxxxxxx
> Cc: bpf@xxxxxxxxxxxxxxx
> Cc: selinux@xxxxxxxxxxxxxxx
> Cc: linux-security-module@xxxxxxxxxxxxxxx
> ---
>   include/linux/lsm/apparmor.h | 17 +++++++++++++++++
>   include/linux/lsm/bpf.h      | 16 ++++++++++++++++
>   include/linux/lsm/selinux.h  | 16 ++++++++++++++++
>   include/linux/lsm/smack.h    | 17 +++++++++++++++++
>   include/linux/security.h     | 20 ++++++++++++++++++++
>   5 files changed, 86 insertions(+)
>   create mode 100644 include/linux/lsm/apparmor.h
>   create mode 100644 include/linux/lsm/bpf.h
>   create mode 100644 include/linux/lsm/selinux.h
>   create mode 100644 include/linux/lsm/smack.h
>
> diff --git a/include/linux/lsm/apparmor.h b/include/linux/lsm/apparmor.h
> new file mode 100644
> index 000000000000..612cbfacb072
> --- /dev/null
> +++ b/include/linux/lsm/apparmor.h
> @@ -0,0 +1,17 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Linux Security Module interface to other subsystems.
> + * AppArmor presents single pointer to an aa_label structure.
> + */
> +#ifndef __LINUX_LSM_APPARMOR_H
> +#define __LINUX_LSM_APPARMOR_H
> +
> +struct aa_label;
> +
> +struct lsm_prop_apparmor {
> +#ifdef CONFIG_SECURITY_APPARMOR
> +	struct aa_label *label;
> +#endif
> +};
> +
> +#endif /* ! __LINUX_LSM_APPARMOR_H */
> diff --git a/include/linux/lsm/bpf.h b/include/linux/lsm/bpf.h
> new file mode 100644
> index 000000000000..8106e206fcef
> --- /dev/null
> +++ b/include/linux/lsm/bpf.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Linux Security Module interface to other subsystems.
> + * BPF may present a single u32 value.
> + */
> +#ifndef __LINUX_LSM_BPF_H
> +#define __LINUX_LSM_BPF_H
> +#include <linux/types.h>
> +
> +struct lsm_prop_bpf {
> +#ifdef CONFIG_BPF_LSM
> +	u32 secid;
> +#endif
> +};
> +
> +#endif /* ! __LINUX_LSM_BPF_H */
> diff --git a/include/linux/lsm/selinux.h b/include/linux/lsm/selinux.h
> new file mode 100644
> index 000000000000..9455a6b5b910
> --- /dev/null
> +++ b/include/linux/lsm/selinux.h
> @@ -0,0 +1,16 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Linux Security Module interface to other subsystems.
> + * SELinux presents a single u32 value which is known as a secid.
> + */
> +#ifndef __LINUX_LSM_SELINUX_H
> +#define __LINUX_LSM_SELINUX_H
> +#include <linux/types.h>
> +
> +struct lsm_prop_selinux {
> +#ifdef CONFIG_SECURITY_SELINUX
> +	u32 secid;
> +#endif
> +};
> +
> +#endif /* ! __LINUX_LSM_SELINUX_H */
> diff --git a/include/linux/lsm/smack.h b/include/linux/lsm/smack.h
> new file mode 100644
> index 000000000000..ff730dd7a734
> --- /dev/null
> +++ b/include/linux/lsm/smack.h
> @@ -0,0 +1,17 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Linux Security Module interface to other subsystems.
> + * Smack presents a pointer into the global Smack label list.
> + */
> +#ifndef __LINUX_LSM_SMACK_H
> +#define __LINUX_LSM_SMACK_H
> +
> +struct smack_known;
> +
> +struct lsm_prop_smack {
> +#ifdef CONFIG_SECURITY_SMACK
> +	struct smack_known *skp;
> +#endif
> +};
> +
> +#endif /* ! __LINUX_LSM_SMACK_H */
> diff --git a/include/linux/security.h b/include/linux/security.h
> index b86ec2afc691..555249a8d121 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -34,6 +34,10 @@
>   #include <linux/sockptr.h>
>   #include <linux/bpf.h>
>   #include <uapi/linux/lsm.h>
> +#include <linux/lsm/selinux.h>
> +#include <linux/lsm/smack.h>
> +#include <linux/lsm/apparmor.h>
> +#include <linux/lsm/bpf.h>
>   
>   struct linux_binprm;
>   struct cred;
> @@ -152,6 +156,22 @@ enum lockdown_reason {
>   	LOCKDOWN_CONFIDENTIALITY_MAX,
>   };
>   
> +/* scaffolding */
> +struct lsm_prop_scaffold {
> +	u32 secid;
> +};
> +
> +/*
> + * Data exported by the security modules
> + */
> +struct lsm_prop {
> +	struct lsm_prop_selinux selinux;
> +	struct lsm_prop_smack smack;
> +	struct lsm_prop_apparmor apparmor;
> +	struct lsm_prop_bpf bpf;
> +	struct lsm_prop_scaffold scaffold;
> +};
> +
>   extern const char *const lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1];
>   extern u32 lsm_active_cnt;
>   extern const struct lsm_id *lsm_idlist[];