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[77.56.209.237]) by smtp.gmail.com with ESMTPSA id l8sm199874wmj.2.2020.03.23.09.44.31 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 23 Mar 2020 09:44:31 -0700 (PDT) From: KP Singh To: linux-kernel@vger.kernel.org, bpf@vger.kernel.org, linux-security-module@vger.kernel.org Cc: Brendan Jackman , Florent Revest , Alexei Starovoitov , Daniel Borkmann , James Morris , Kees Cook , Paul Turner , Jann Horn , Florent Revest , Brendan Jackman , Greg Kroah-Hartman Subject: [PATCH bpf-next v5 3/7] bpf: lsm: provide attachment points for BPF LSM programs Date: Mon, 23 Mar 2020 17:44:11 +0100 Message-Id: <20200323164415.12943-4-kpsingh@chromium.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200323164415.12943-1-kpsingh@chromium.org> References: <20200323164415.12943-1-kpsingh@chromium.org> MIME-Version: 1.0 Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: From: KP Singh When CONFIG_BPF_LSM is enabled, nops functions, bpf_lsm_, are generated for each LSM hook. These nops are initialized as LSM hooks in a subsequent patch. Signed-off-by: KP Singh Reviewed-by: Brendan Jackman Reviewed-by: Florent Revest Acked-by: Yonghong Song Reviewed-by: Kees Cook --- include/linux/bpf_lsm.h | 21 +++++++++++++++++++++ kernel/bpf/bpf_lsm.c | 19 +++++++++++++++++++ 2 files changed, 40 insertions(+) create mode 100644 include/linux/bpf_lsm.h diff --git a/include/linux/bpf_lsm.h b/include/linux/bpf_lsm.h new file mode 100644 index 000000000000..c6423a140220 --- /dev/null +++ b/include/linux/bpf_lsm.h @@ -0,0 +1,21 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +/* + * Copyright (C) 2020 Google LLC. + */ + +#ifndef _LINUX_BPF_LSM_H +#define _LINUX_BPF_LSM_H + +#include +#include + +#ifdef CONFIG_BPF_LSM + +#define LSM_HOOK(RET, NAME, ...) RET bpf_lsm_##NAME(__VA_ARGS__); +#include +#undef LSM_HOOK + +#endif /* CONFIG_BPF_LSM */ + +#endif /* _LINUX_BPF_LSM_H */ diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c index 82875039ca90..530d137f7a84 100644 --- a/kernel/bpf/bpf_lsm.c +++ b/kernel/bpf/bpf_lsm.c @@ -7,6 +7,25 @@ #include #include #include +#include +#include + +/* For every LSM hook that allows attachment of BPF programs, declare a NOP + * function where a BPF program can be attached as an fexit trampoline. + */ +#define LSM_HOOK(RET, NAME, ...) LSM_HOOK_##RET(NAME, __VA_ARGS__) + +#define LSM_HOOK_int(NAME, ...) \ +noinline __weak int bpf_lsm_##NAME(__VA_ARGS__) \ +{ \ + return 0; \ +} + +#define LSM_HOOK_void(NAME, ...) \ +noinline __weak void bpf_lsm_##NAME(__VA_ARGS__) {} + +#include +#undef LSM_HOOK const struct bpf_prog_ops lsm_prog_ops = { };