// SPDX-License-Identifier: GPL-2.0/* * Copyright (c) 2020 Facebook * Copyright 2020 Google LLC. */ #include <linux/pid.h>#include <linux/sched.h>#include <linux/rculist.h>#include <linux/list.h>#include <linux/hash.h>#include <linux/types.h>#include <linux/spinlock.h>#include <linux/bpf.h>#include <linux/bpf_local_storage.h>#include <linux/filter.h>#include <uapi/linux/btf.h>#include <linux/btf_ids.h>#include <linux/rcupdate_trace.h> DEFINE_BPF_STORAGE_CACHE(task_cache); static struct bpf_local_storage __rcu **task_storage_ptr(void *owner){	struct task_struct *task = owner; 	return &task->bpf_storage;} static struct bpf_local_storage_data *task_storage_lookup(struct task_struct *task, struct bpf_map *map,		    bool cacheit_lockit){	struct bpf_local_storage *task_storage;	struct bpf_local_storage_map *smap; 	task_storage =		rcu_dereference_check(task->bpf_storage, bpf_rcu_lock_held());	if (!task_storage)		return NULL; 	smap = (struct bpf_local_storage_map *)map;	return bpf_local_storage_lookup(task_storage, smap, cacheit_lockit);} void bpf_task_storage_free(struct task_struct *task){	struct bpf_local_storage *local_storage; 	rcu_read_lock(); 	local_storage = rcu_dereference(task->bpf_storage);	if (!local_storage)		goto out; 	bpf_local_storage_destroy(local_storage);out:	rcu_read_unlock();} static void *bpf_pid_task_storage_lookup_elem(struct bpf_map *map, void *key){	struct bpf_local_storage_data *sdata;	struct task_struct *task;	unsigned int f_flags;	struct pid *pid;	int fd, err; 	fd = *(int *)key;	pid = pidfd_get_pid(fd, &f_flags);	if (IS_ERR(pid))		return ERR_CAST(pid); 	/* We should be in an RCU read side critical section, it should be safe	 * to call pid_task.	 */	WARN_ON_ONCE(!rcu_read_lock_held());	task = pid_task(pid, PIDTYPE_PID);	if (!task) {		err = -ENOENT;		goto out;	} 	sdata = task_storage_lookup(task, map, true);	put_pid(pid);	return sdata ? sdata->data : NULL;out:	put_pid(pid);	return ERR_PTR(err);} static long bpf_pid_task_storage_update_elem(struct bpf_map *map, void *key,					     void *value, u64 map_flags){	struct bpf_local_storage_data *sdata;	struct task_struct *task;	unsigned int f_flags;	struct pid *pid;	int fd, err; 	if ((map_flags & BPF_F_LOCK) && btf_record_has_field(map->record, BPF_UPTR))		return -EOPNOTSUPP; 	fd = *(int *)key;	pid = pidfd_get_pid(fd, &f_flags);	if (IS_ERR(pid))		return PTR_ERR(pid); 	/* We should be in an RCU read side critical section, it should be safe	 * to call pid_task.	 */	WARN_ON_ONCE(!rcu_read_lock_held());	task = pid_task(pid, PIDTYPE_PID);	if (!task) {		err = -ENOENT;		goto out;	} 	sdata = bpf_local_storage_update(		task, (struct bpf_local_storage_map *)map, value, map_flags,		true); 	err = PTR_ERR_OR_ZERO(sdata);out:	put_pid(pid);	return err;} static int task_storage_delete(struct task_struct *task, struct bpf_map *map){	struct bpf_local_storage_data *sdata; 	sdata = task_storage_lookup(task, map, false);	if (!sdata)		return -ENOENT; 	return bpf_selem_unlink(SELEM(sdata));} static long bpf_pid_task_storage_delete_elem(struct bpf_map *map, void *key){	struct task_struct *task;	unsigned int f_flags;	struct pid *pid;	int fd, err; 	fd = *(int *)key;	pid = pidfd_get_pid(fd, &f_flags);	if (IS_ERR(pid))		return PTR_ERR(pid); 	/* We should be in an RCU read side critical section, it should be safe	 * to call pid_task.	 */	WARN_ON_ONCE(!rcu_read_lock_held());	task = pid_task(pid, PIDTYPE_PID);	if (!task) {		err = -ENOENT;		goto out;	} 	err = task_storage_delete(task, map);out:	put_pid(pid);	return err;} BPF_CALL_4(bpf_task_storage_get, struct bpf_map *, map, struct task_struct *,	   task, void *, value, u64, flags){	struct bpf_local_storage_data *sdata; 	WARN_ON_ONCE(!bpf_rcu_lock_held());	if (flags & ~BPF_LOCAL_STORAGE_GET_F_CREATE || !task)		return (unsigned long)NULL; 	sdata = task_storage_lookup(task, map, true);	if (sdata)		return (unsigned long)sdata->data; 	/* only allocate new storage, when the task is refcounted */	if (refcount_read(&task->usage) &&	    (flags & BPF_LOCAL_STORAGE_GET_F_CREATE)) {		sdata = bpf_local_storage_update(			task, (struct bpf_local_storage_map *)map, value,			BPF_NOEXIST, false);		return IS_ERR(sdata) ? (unsigned long)NULL : (unsigned long)sdata->data;	} 	return (unsigned long)NULL;} BPF_CALL_2(bpf_task_storage_delete, struct bpf_map *, map, struct task_struct *,	   task){	WARN_ON_ONCE(!bpf_rcu_lock_held());	if (!task)		return -EINVAL; 	/* This helper must only be called from places where the lifetime of the task	 * is guaranteed. Either by being refcounted or by being protected	 * by an RCU read-side critical section.	 */	return task_storage_delete(task, map);} static int notsupp_get_next_key(struct bpf_map *map, void *key, void *next_key){	return -ENOTSUPP;} static struct bpf_map *task_storage_map_alloc(union bpf_attr *attr){	return bpf_local_storage_map_alloc(attr, &task_cache);} static void task_storage_map_free(struct bpf_map *map){	bpf_local_storage_map_free(map, &task_cache);} BTF_ID_LIST_GLOBAL_SINGLE(bpf_local_storage_map_btf_id, struct, bpf_local_storage_map)const struct bpf_map_ops task_storage_map_ops = {	.map_meta_equal = bpf_map_meta_equal,	.map_alloc_check = bpf_local_storage_map_alloc_check,	.map_alloc = task_storage_map_alloc,	.map_free = task_storage_map_free,	.map_get_next_key = notsupp_get_next_key,	.map_lookup_elem = bpf_pid_task_storage_lookup_elem,	.map_update_elem = bpf_pid_task_storage_update_elem,	.map_delete_elem = bpf_pid_task_storage_delete_elem,	.map_check_btf = bpf_local_storage_map_check_btf,	.map_mem_usage = bpf_local_storage_map_mem_usage,	.map_btf_id = &bpf_local_storage_map_btf_id[0],	.map_owner_storage_ptr = task_storage_ptr,}; const struct bpf_func_proto bpf_task_storage_get_proto = {	.func = bpf_task_storage_get,	.gpl_only = false,	.ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,	.arg1_type = ARG_CONST_MAP_PTR,	.arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL,	.arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK],	.arg3_type = ARG_PTR_TO_MAP_VALUE_OR_NULL,	.arg4_type = ARG_ANYTHING,}; const struct bpf_func_proto bpf_task_storage_delete_proto = {	.func = bpf_task_storage_delete,	.gpl_only = false,	.ret_type = RET_INTEGER,	.arg1_type = ARG_CONST_MAP_PTR,	.arg2_type = ARG_PTR_TO_BTF_ID_OR_NULL,	.arg2_btf_id = &btf_tracing_ids[BTF_TRACING_TYPE_TASK],};