[PATCH v9 10/17] bpf, lsm: refactor bpf_map_alloc/bpf_map_free LSM hooks

[Paul Moore]

On Nov  3, 2023 Andrii Nakryiko <andrii at kernel.org> wrote:
> 
> Similarly to bpf_prog_alloc LSM hook, rename and extend bpf_map_alloc
> hook into bpf_map_create, taking not just struct bpf_map, but also
> bpf_attr and bpf_token, to give a fuller context to LSMs.
> 
> Unlike bpf_prog_alloc, there is no need to move the hook around, as it
> currently is firing right before allocating BPF map ID and FD, which
> seems to be a sweet spot.
> 
> But like bpf_prog_alloc/bpf_prog_free combo, make sure that bpf_map_free
> LSM hook is called even if bpf_map_create hook returned error, as if few
> LSMs are combined together it could be that one LSM successfully
> allocated security blob for its needs, while subsequent LSM rejected BPF
> map creation. The former LSM would still need to free up LSM blob, so we
> need to ensure security_bpf_map_free() is called regardless of the
> outcome.
> 
> Signed-off-by: Andrii Nakryiko <andrii at kernel.org>
> ---
>  include/linux/lsm_hook_defs.h |  5 +++--
>  include/linux/security.h      |  6 ++++--
>  kernel/bpf/bpf_lsm.c          |  6 +++---
>  kernel/bpf/syscall.c          |  4 ++--
>  security/security.c           | 16 ++++++++++------
>  security/selinux/hooks.c      |  7 ++++---
>  6 files changed, 26 insertions(+), 18 deletions(-)

Acked-by: Paul Moore <paul at paul-moore.com>

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