Commit 6f100640 authored Nov 13, 2020 by KP Singh Committed by Daniel Borkmann Nov 13, 2020

bpf: Expose bpf_d_path helper to sleepable LSM hooks



Sleepable hooks are never called from an NMI/interrupt context, so it
is safe to use the bpf_d_path helper in LSM programs attaching to these
hooks.

The helper is not restricted to sleepable programs and merely uses the
list of sleepable hooks as the initial subset of LSM hooks where it can
be used.

Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20201113005930.541956-3-kpsingh@chromium.org

parent 423f1610

kernel/trace/bpf_trace.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -16,6 +16,8 @@
		#include <linux/syscalls.h>
		#include <linux/error-injection.h>
		#include <linux/btf_ids.h>
		#include <linux/bpf_lsm.h>

		#include <net/bpf_sk_storage.h>

		#include <uapi/linux/bpf.h>
		@@ -1179,7 +1181,11 @@ BTF_SET_END(btf_allowlist_d_path)

		static bool bpf_d_path_allowed(const struct bpf_prog *prog)
		{
		return btf_id_set_contains(&btf_allowlist_d_path, prog->aux->attach_btf_id);
		if (prog->type == BPF_PROG_TYPE_LSM)
		return bpf_lsm_is_sleepable_hook(prog->aux->attach_btf_id);

		return btf_id_set_contains(&btf_allowlist_d_path,
		prog->aux->attach_btf_id);
		}

		BTF_ID_LIST_SINGLE(bpf_d_path_btf_ids, struct, path)

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