Re: [PATCH v38 01/39] LSM: Identify modules by more than name

[Georgia Garcia]

Hi!

On Tue, 2022-09-27 at 12:53 -0700, Casey Schaufler wrote:
> Create a struct lsm_id to contain identifying information
> about Linux Security Modules (LSMs). At inception this contains
> a single member, which is the name of the module. Change the
> security_add_hooks() interface to use this structure. Change
> the individual modules to maintain their own struct lsm_id and
> pass it to security_add_hooks().
> 
> Signed-off-by: Casey Schaufler <casey@xxxxxxxxxxxxxxxx>
> ---
>  include/linux/lsm_hooks.h    | 11 +++++++++--
>  security/apparmor/lsm.c      |  6 +++++-
>  security/bpf/hooks.c         | 11 ++++++++++-
>  security/commoncap.c         |  6 +++++-
>  security/landlock/cred.c     |  2 +-
>  security/landlock/fs.c       |  2 +-
>  security/landlock/ptrace.c   |  2 +-
>  security/landlock/setup.c    |  4 ++++
>  security/landlock/setup.h    |  1 +
>  security/loadpin/loadpin.c   |  7 ++++++-
>  security/lockdown/lockdown.c |  6 +++++-
>  security/safesetid/lsm.c     |  7 ++++++-
>  security/security.c          | 12 ++++++------
>  security/selinux/hooks.c     |  7 ++++++-
>  security/smack/smack_lsm.c   |  6 +++++-
>  security/tomoyo/tomoyo.c     |  7 ++++++-
>  security/yama/yama_lsm.c     |  6 +++++-
>  17 files changed, 82 insertions(+), 21 deletions(-)
> 
> diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h
> index 3aa6030302f5..23054881eb08 100644
> --- a/include/linux/lsm_hooks.h
> +++ b/include/linux/lsm_hooks.h
> @@ -1598,6 +1598,13 @@ struct security_hook_heads {
>  	#undef LSM_HOOK
>  } __randomize_layout;
>  
> +/*
> + * Information that identifies a security module.
> + */
> +struct lsm_id {
> +	const char	*lsm;		/* Name of the LSM */
> +};
> +
>  /*
>   * Security module hook list structure.
>   * For use with generic list macros for common operations.
> @@ -1606,7 +1613,7 @@ struct security_hook_list {
>  	struct hlist_node		list;
>  	struct hlist_head		*head;
>  	union security_list_options	hook;
> -	const char			*lsm;
> +	struct lsm_id			*lsmid;
>  } __randomize_layout;
>  
>  /*
> @@ -1641,7 +1648,7 @@ extern struct security_hook_heads security_hook_heads;
>  extern char *lsm_names;
>  
>  extern void security_add_hooks(struct security_hook_list *hooks, int count,
> -				const char *lsm);
> +			       struct lsm_id *lsmid);
>  
>  #define LSM_FLAG_LEGACY_MAJOR	BIT(0)
>  #define LSM_FLAG_EXCLUSIVE	BIT(1)
> diff --git a/security/apparmor/lsm.c b/security/apparmor/lsm.c
> index e29cade7b662..b71f7d4159d7 100644
> --- a/security/apparmor/lsm.c
> +++ b/security/apparmor/lsm.c
> @@ -1202,6 +1202,10 @@ struct lsm_blob_sizes apparmor_blob_sizes __lsm_ro_after_init = {
>  	.lbs_task = sizeof(struct aa_task_ctx),
>  };
>  
> +static struct lsm_id apparmor_lsmid __lsm_ro_after_init = {
> +	.lsm      = "apparmor",
> +};
> +
>  static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
>  	LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),
>  	LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),
> @@ -1897,7 +1901,7 @@ static int __init apparmor_init(void)
>  		goto buffers_out;
>  	}
>  	security_add_hooks(apparmor_hooks, ARRAY_SIZE(apparmor_hooks),
> -				"apparmor");
> +				&apparmor_lsmid);
>  
>  	/* Report that AppArmor successfully initialized */
>  	apparmor_initialized = 1;
> diff --git a/security/bpf/hooks.c b/security/bpf/hooks.c
> index e5971fa74fd7..e50de3abfde2 100644
> --- a/security/bpf/hooks.c
> +++ b/security/bpf/hooks.c
> @@ -15,9 +15,18 @@ static struct security_hook_list bpf_lsm_hooks[] __lsm_ro_after_init = {
>  	LSM_HOOK_INIT(task_free, bpf_task_storage_free),
>  };
>  
> +/*
> + * slot has to be LSMBLOB_NEEDED because some of the hooks
> + * supplied by this module require a slot.
> + */
> +struct lsm_id bpf_lsmid __lsm_ro_after_init = {
> +	.lsm      = "bpf",
> +};

Can bpf_lsmid be static too?

> +
>  static int __init bpf_lsm_init(void)
>  {
> -	security_add_hooks(bpf_lsm_hooks, ARRAY_SIZE(bpf_lsm_hooks), "bpf");
> +	security_add_hooks(bpf_lsm_hooks, ARRAY_SIZE(bpf_lsm_hooks),
> +			   &bpf_lsmid);
>  	pr_info("LSM support for eBPF active\n");
>  	return 0;
>  }

Thanks