diff options
Diffstat (limited to 'kernel/bpf/bpf_lsm.c')
-rw-r--r-- | kernel/bpf/bpf_lsm.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/kernel/bpf/bpf_lsm.c b/kernel/bpf/bpf_lsm.c new file mode 100644 index 000000000..56cc5a915 --- /dev/null +++ b/kernel/bpf/bpf_lsm.c @@ -0,0 +1,77 @@ +// SPDX-License-Identifier: GPL-2.0 + +/* + * Copyright (C) 2020 Google LLC. + */ + +#include <linux/filter.h> +#include <linux/bpf.h> +#include <linux/btf.h> +#include <linux/lsm_hooks.h> +#include <linux/bpf_lsm.h> +#include <linux/kallsyms.h> +#include <linux/bpf_verifier.h> +#include <net/bpf_sk_storage.h> +#include <linux/bpf_local_storage.h> +#include <linux/btf_ids.h> + +/* For every LSM hook that allows attachment of BPF programs, declare a nop + * function where a BPF program can be attached. + */ +#define LSM_HOOK(RET, DEFAULT, NAME, ...) \ +noinline RET bpf_lsm_##NAME(__VA_ARGS__) \ +{ \ + return DEFAULT; \ +} + +#include <linux/lsm_hook_defs.h> +#undef LSM_HOOK + +#define LSM_HOOK(RET, DEFAULT, NAME, ...) BTF_ID(func, bpf_lsm_##NAME) +BTF_SET_START(bpf_lsm_hooks) +#include <linux/lsm_hook_defs.h> +#undef LSM_HOOK +BTF_SET_END(bpf_lsm_hooks) + +int bpf_lsm_verify_prog(struct bpf_verifier_log *vlog, + const struct bpf_prog *prog) +{ + if (!prog->gpl_compatible) { + bpf_log(vlog, + "LSM programs must have a GPL compatible license\n"); + return -EINVAL; + } + + if (!btf_id_set_contains(&bpf_lsm_hooks, prog->aux->attach_btf_id)) { + bpf_log(vlog, "attach_btf_id %u points to wrong type name %s\n", + prog->aux->attach_btf_id, prog->aux->attach_func_name); + return -EINVAL; + } + + return 0; +} + +static const struct bpf_func_proto * +bpf_lsm_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) +{ + switch (func_id) { + case BPF_FUNC_inode_storage_get: + return &bpf_inode_storage_get_proto; + case BPF_FUNC_inode_storage_delete: + return &bpf_inode_storage_delete_proto; + case BPF_FUNC_sk_storage_get: + return &bpf_sk_storage_get_proto; + case BPF_FUNC_sk_storage_delete: + return &bpf_sk_storage_delete_proto; + default: + return tracing_prog_func_proto(func_id, prog); + } +} + +const struct bpf_prog_ops lsm_prog_ops = { +}; + +const struct bpf_verifier_ops lsm_verifier_ops = { + .get_func_proto = bpf_lsm_func_proto, + .is_valid_access = btf_ctx_access, +}; |