![Daniel Borkmann](/assets/img/avatar_default.png)
This patch converts all helpers that can use ARG_PTR_TO_RAW_STACK as argument type. For tc programs this is bpf_skb_load_bytes(), bpf_skb_get_tunnel_key(), bpf_skb_get_tunnel_opt(). For tracing, this optimizes bpf_get_current_comm() and bpf_probe_read(). The check in bpf_skb_load_bytes() for MAX_BPF_STACK can also be removed since the verifier already makes sure we stay within bounds on stack buffers. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
189 lines
5 KiB
C
189 lines
5 KiB
C
/* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*/
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#include <linux/bpf.h>
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#include <linux/rcupdate.h>
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#include <linux/random.h>
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#include <linux/smp.h>
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#include <linux/ktime.h>
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#include <linux/sched.h>
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#include <linux/uidgid.h>
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/* If kernel subsystem is allowing eBPF programs to call this function,
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* inside its own verifier_ops->get_func_proto() callback it should return
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* bpf_map_lookup_elem_proto, so that verifier can properly check the arguments
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*
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* Different map implementations will rely on rcu in map methods
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* lookup/update/delete, therefore eBPF programs must run under rcu lock
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* if program is allowed to access maps, so check rcu_read_lock_held in
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* all three functions.
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*/
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static u64 bpf_map_lookup_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
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{
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/* verifier checked that R1 contains a valid pointer to bpf_map
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* and R2 points to a program stack and map->key_size bytes were
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* initialized
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*/
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struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
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void *key = (void *) (unsigned long) r2;
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void *value;
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WARN_ON_ONCE(!rcu_read_lock_held());
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value = map->ops->map_lookup_elem(map, key);
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/* lookup() returns either pointer to element value or NULL
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* which is the meaning of PTR_TO_MAP_VALUE_OR_NULL type
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*/
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return (unsigned long) value;
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}
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const struct bpf_func_proto bpf_map_lookup_elem_proto = {
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.func = bpf_map_lookup_elem,
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.gpl_only = false,
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.ret_type = RET_PTR_TO_MAP_VALUE_OR_NULL,
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.arg1_type = ARG_CONST_MAP_PTR,
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.arg2_type = ARG_PTR_TO_MAP_KEY,
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};
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static u64 bpf_map_update_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
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{
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struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
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void *key = (void *) (unsigned long) r2;
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void *value = (void *) (unsigned long) r3;
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WARN_ON_ONCE(!rcu_read_lock_held());
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return map->ops->map_update_elem(map, key, value, r4);
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}
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const struct bpf_func_proto bpf_map_update_elem_proto = {
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.func = bpf_map_update_elem,
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.gpl_only = false,
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.ret_type = RET_INTEGER,
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.arg1_type = ARG_CONST_MAP_PTR,
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.arg2_type = ARG_PTR_TO_MAP_KEY,
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.arg3_type = ARG_PTR_TO_MAP_VALUE,
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.arg4_type = ARG_ANYTHING,
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};
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static u64 bpf_map_delete_elem(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
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{
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struct bpf_map *map = (struct bpf_map *) (unsigned long) r1;
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void *key = (void *) (unsigned long) r2;
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WARN_ON_ONCE(!rcu_read_lock_held());
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return map->ops->map_delete_elem(map, key);
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}
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const struct bpf_func_proto bpf_map_delete_elem_proto = {
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.func = bpf_map_delete_elem,
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.gpl_only = false,
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.ret_type = RET_INTEGER,
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.arg1_type = ARG_CONST_MAP_PTR,
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.arg2_type = ARG_PTR_TO_MAP_KEY,
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};
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const struct bpf_func_proto bpf_get_prandom_u32_proto = {
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.func = bpf_user_rnd_u32,
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.gpl_only = false,
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.ret_type = RET_INTEGER,
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};
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static u64 bpf_get_smp_processor_id(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
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{
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return raw_smp_processor_id();
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}
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const struct bpf_func_proto bpf_get_smp_processor_id_proto = {
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.func = bpf_get_smp_processor_id,
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.gpl_only = false,
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.ret_type = RET_INTEGER,
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};
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static u64 bpf_ktime_get_ns(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
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{
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/* NMI safe access to clock monotonic */
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return ktime_get_mono_fast_ns();
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}
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const struct bpf_func_proto bpf_ktime_get_ns_proto = {
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.func = bpf_ktime_get_ns,
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.gpl_only = true,
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.ret_type = RET_INTEGER,
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};
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static u64 bpf_get_current_pid_tgid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
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{
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struct task_struct *task = current;
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if (!task)
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return -EINVAL;
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return (u64) task->tgid << 32 | task->pid;
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}
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const struct bpf_func_proto bpf_get_current_pid_tgid_proto = {
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.func = bpf_get_current_pid_tgid,
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.gpl_only = false,
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.ret_type = RET_INTEGER,
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};
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static u64 bpf_get_current_uid_gid(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
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{
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struct task_struct *task = current;
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kuid_t uid;
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kgid_t gid;
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if (!task)
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return -EINVAL;
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current_uid_gid(&uid, &gid);
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return (u64) from_kgid(&init_user_ns, gid) << 32 |
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from_kuid(&init_user_ns, uid);
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}
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const struct bpf_func_proto bpf_get_current_uid_gid_proto = {
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.func = bpf_get_current_uid_gid,
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.gpl_only = false,
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.ret_type = RET_INTEGER,
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};
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static u64 bpf_get_current_comm(u64 r1, u64 size, u64 r3, u64 r4, u64 r5)
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{
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struct task_struct *task = current;
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char *buf = (char *) (long) r1;
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if (unlikely(!task))
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goto err_clear;
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strncpy(buf, task->comm, size);
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/* Verifier guarantees that size > 0. For task->comm exceeding
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* size, guarantee that buf is %NUL-terminated. Unconditionally
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* done here to save the size test.
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*/
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buf[size - 1] = 0;
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return 0;
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err_clear:
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memset(buf, 0, size);
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return -EINVAL;
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}
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const struct bpf_func_proto bpf_get_current_comm_proto = {
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.func = bpf_get_current_comm,
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.gpl_only = false,
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.ret_type = RET_INTEGER,
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.arg1_type = ARG_PTR_TO_RAW_STACK,
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.arg2_type = ARG_CONST_STACK_SIZE,
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};
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