[PATCH v9 17/17] bpf, selinux: allocate bpf_security_struct per BPF token

[Paul Moore]

On Nov  3, 2023 Andrii Nakryiko <andrii at kernel.org> wrote:
> 
> Utilize newly added bpf_token_create/bpf_token_free LSM hooks to
> allocate struct bpf_security_struct for each BPF token object in
> SELinux. This just follows similar pattern for BPF prog and map.
> 
> Signed-off-by: Andrii Nakryiko <andrii at kernel.org>
> ---
>  security/selinux/hooks.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)

Thanks Andrii, we'll need some additional code to fully enable the
BPF tokens on a SELinux system but I can help provide that if you'd
like.  Although I might not be able to get to that until after the
merge window closes.

> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 002351ab67b7..1501e95366a1 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -6828,6 +6828,29 @@ static void selinux_bpf_prog_free(struct bpf_prog *prog)
>  	prog->aux->security = NULL;
>  	kfree(bpfsec);
>  }
> +
> +static int selinux_bpf_token_create(struct bpf_token *token, union bpf_attr *attr,
> +				    struct path *path)
> +{
> +	struct bpf_security_struct *bpfsec;
> +
> +	bpfsec = kzalloc(sizeof(*bpfsec), GFP_KERNEL);
> +	if (!bpfsec)
> +		return -ENOMEM;
> +
> +	bpfsec->sid = current_sid();
> +	token->security = bpfsec;
> +
> +	return 0;
> +}
> +
> +static void selinux_bpf_token_free(struct bpf_token *token)
> +{
> +	struct bpf_security_struct *bpfsec = token->security;
> +
> +	token->security = NULL;
> +	kfree(bpfsec);
> +}
>  #endif
>  
>  struct lsm_blob_sizes selinux_blob_sizes __ro_after_init = {
> @@ -7183,6 +7206,7 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = {
>  	LSM_HOOK_INIT(bpf_prog, selinux_bpf_prog),
>  	LSM_HOOK_INIT(bpf_map_free, selinux_bpf_map_free),
>  	LSM_HOOK_INIT(bpf_prog_free, selinux_bpf_prog_free),
> +	LSM_HOOK_INIT(bpf_token_free, selinux_bpf_token_free),
>  #endif
>  
>  #ifdef CONFIG_PERF_EVENTS
> @@ -7241,6 +7265,7 @@ static struct security_hook_list selinux_hooks[] __ro_after_init = {
>  #ifdef CONFIG_BPF_SYSCALL
>  	LSM_HOOK_INIT(bpf_map_create, selinux_bpf_map_create),
>  	LSM_HOOK_INIT(bpf_prog_load, selinux_bpf_prog_load),
> +	LSM_HOOK_INIT(bpf_token_create, selinux_bpf_token_create),
>  #endif
>  #ifdef CONFIG_PERF_EVENTS
>  	LSM_HOOK_INIT(perf_event_alloc, selinux_perf_event_alloc),
> -- 
> 2.34.1

--
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