cregit-Linux how code gets into the kernel

Release 4.7 kernel/bpf/helpers.c

Directory: kernel/bpf
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of version 2 of the GNU General Public
 * License as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 */
#include <linux/bpf.h>
#include <linux/rcupdate.h>
#include <linux/random.h>
#include <linux/smp.h>
#include <linux/ktime.h>
#include <linux/sched.h>
#include <linux/uidgid.h>

/* If kernel subsystem is allowing eBPF programs to call this function,
 * inside its own verifier_ops->get_func_proto() callback it should return
 * bpf_map_lookup_elem_proto, so that verifier can properly check the arguments
 *
 * Different map implementations will rely on rcu in map methods
 * lookup/update/delete, therefore eBPF programs must run under rcu lock
 * if program is allowed to access maps, so check rcu_read_lock_held in
 * all three functions.
 */

static u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) { /* verifier checked that R1 contains a valid pointer to bpf_map * and R2 points to a program stack and map->key_size bytes were * initialized */ struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; void *key = (void *) (unsigned long) r2; void *value; WARN_ON_ONCE(!rcu_read_lock_held()); value = map->ops->map_lookup_elem(map, key); /* lookup() returns either pointer to element value or NULL * which is the meaning of PTR_TO_MAP_VALUE_OR_NULL type */ return (unsigned long) value; }

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alexei starovoitovalexei starovoitov84100.00%1100.00%
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const struct bpf_func_proto bpf_map_lookup_elem_proto = { .func = bpf_map_lookup_elem, .gpl_only = false, .ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL, .arg1_type = ARG_CONST_MAP_PTR, .arg2_type = ARG_PTR_TO_MAP_KEY, };
static u64 bpf_map_update_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) { struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; void *key = (void *) (unsigned long) r2; void *value = (void *) (unsigned long) r3; WARN_ON_ONCE(!rcu_read_lock_held()); return map->ops->map_update_elem(map, key, value, r4); }

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alexei starovoitovalexei starovoitov88100.00%1100.00%
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const struct bpf_func_proto bpf_map_update_elem_proto = { .func = bpf_map_update_elem, .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_CONST_MAP_PTR, .arg2_type = ARG_PTR_TO_MAP_KEY, .arg3_type = ARG_PTR_TO_MAP_VALUE, .arg4_type = ARG_ANYTHING, };
static u64 bpf_map_delete_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) { struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; void *key = (void *) (unsigned long) r2; WARN_ON_ONCE(!rcu_read_lock_held()); return map->ops->map_delete_elem(map, key); }

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alexei starovoitovalexei starovoitov70100.00%1100.00%
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const struct bpf_func_proto bpf_map_delete_elem_proto = { .func = bpf_map_delete_elem, .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_CONST_MAP_PTR, .arg2_type = ARG_PTR_TO_MAP_KEY, }; const struct bpf_func_proto bpf_get_prandom_u32_proto = { .func = bpf_user_rnd_u32, .gpl_only = false, .ret_type = RET_INTEGER, };
static u64 bpf_get_smp_processor_id(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) { return raw_smp_processor_id(); }

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daniel borkmanndaniel borkmann25100.00%1100.00%
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const struct bpf_func_proto bpf_get_smp_processor_id_proto = { .func = bpf_get_smp_processor_id, .gpl_only = false, .ret_type = RET_INTEGER, };
static u64 bpf_ktime_get_ns(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) { /* NMI safe access to clock monotonic */ return ktime_get_mono_fast_ns(); }

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daniel borkmanndaniel borkmann26100.00%1100.00%
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const struct bpf_func_proto bpf_ktime_get_ns_proto = { .func = bpf_ktime_get_ns, .gpl_only = true, .ret_type = RET_INTEGER, };
static u64 bpf_get_current_pid_tgid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) { struct task_struct *task = current; if (!task) return -EINVAL; return (u64) task->tgid << 32 | task->pid; }

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const struct bpf_func_proto bpf_get_current_pid_tgid_proto = { .func = bpf_get_current_pid_tgid, .gpl_only = false, .ret_type = RET_INTEGER, };
static u64 bpf_get_current_uid_gid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5) { struct task_struct *task = current; kuid_t uid; kgid_t gid; if (!task) return -EINVAL; current_uid_gid(&uid, &gid); return (u64) from_kgid(&init_user_ns, gid) << 32 | from_kuid(&init_user_ns, uid); }

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alexei starovoitovalexei starovoitov74100.00%1100.00%
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const struct bpf_func_proto bpf_get_current_uid_gid_proto = { .func = bpf_get_current_uid_gid, .gpl_only = false, .ret_type = RET_INTEGER, };
static u64 bpf_get_current_comm(u64 r1, u64 size, u64 r3, u64 r4, u64 r5) { struct task_struct *task = current; char *buf = (char *) (long) r1; if (unlikely(!task)) goto err_clear; strncpy(buf, task->comm, size); /* Verifier guarantees that size > 0. For task->comm exceeding * size, guarantee that buf is %NUL-terminated. Unconditionally * done here to save the size test. */ buf[size - 1] = 0; return 0; err_clear: memset(buf, 0, size); return -EINVAL; }

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alexei starovoitovalexei starovoitov6065.93%150.00%
daniel borkmanndaniel borkmann3134.07%150.00%
Total91100.00%2100.00%

const struct bpf_func_proto bpf_get_current_comm_proto = { .func = bpf_get_current_comm, .gpl_only = false, .ret_type = RET_INTEGER, .arg1_type = ARG_PTR_TO_RAW_STACK, .arg2_type = ARG_CONST_STACK_SIZE, };

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alexei starovoitovalexei starovoitov61979.36%225.00%
daniel borkmanndaniel borkmann16120.64%675.00%
Total780100.00%8100.00%
Directory: kernel/bpf
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