linux/security/bpf/hooks.c
KP Singh 4cf1bc1f10 bpf: Implement task local storage
Similar to bpf_local_storage for sockets and inodes add local storage
for task_struct.

The life-cycle of storage is managed with the life-cycle of the
task_struct.  i.e. the storage is destroyed along with the owning task
with a callback to the bpf_task_storage_free from the task_free LSM
hook.

The BPF LSM allocates an __rcu pointer to the bpf_local_storage in
the security blob which are now stackable and can co-exist with other
LSMs.

The userspace map operations can be done by using a pid fd as a key
passed to the lookup, update and delete operations.

Signed-off-by: KP Singh <kpsingh@google.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Song Liu <songliubraving@fb.com>
Acked-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/bpf/20201106103747.2780972-3-kpsingh@chromium.org
2020-11-06 08:08:37 -08:00

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C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2020 Google LLC.
*/
#include <linux/lsm_hooks.h>
#include <linux/bpf_lsm.h>
static struct security_hook_list bpf_lsm_hooks[] __lsm_ro_after_init = {
#define LSM_HOOK(RET, DEFAULT, NAME, ...) \
LSM_HOOK_INIT(NAME, bpf_lsm_##NAME),
#include <linux/lsm_hook_defs.h>
#undef LSM_HOOK
LSM_HOOK_INIT(inode_free_security, bpf_inode_storage_free),
LSM_HOOK_INIT(task_free, bpf_task_storage_free),
};
static int __init bpf_lsm_init(void)
{
security_add_hooks(bpf_lsm_hooks, ARRAY_SIZE(bpf_lsm_hooks), "bpf");
pr_info("LSM support for eBPF active\n");
return 0;
}
struct lsm_blob_sizes bpf_lsm_blob_sizes __lsm_ro_after_init = {
.lbs_inode = sizeof(struct bpf_storage_blob),
.lbs_task = sizeof(struct bpf_storage_blob),
};
DEFINE_LSM(bpf) = {
.name = "bpf",
.init = bpf_lsm_init,
.blobs = &bpf_lsm_blob_sizes
};