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linux-stable/net/bpf/test_run.c
Song Liu 963ec27a10 bpf: fix raw_tp test run in preempt kernel 
In preempt kernel, BPF_PROG_TEST_RUN on raw_tp triggers:

[   35.874974] BUG: using smp_processor_id() in preemptible [00000000]
code: new_name/87
[   35.893983] caller is bpf_prog_test_run_raw_tp+0xd4/0x1b0
[   35.900124] CPU: 1 PID: 87 Comm: new_name Not tainted 5.9.0-rc6-g615bd02bf #1
[   35.907358] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.10.2-1ubuntu1 04/01/2014
[   35.916941] Call Trace:
[   35.919660]  dump_stack+0x77/0x9b
[   35.923273]  check_preemption_disabled+0xb4/0xc0
[   35.928376]  bpf_prog_test_run_raw_tp+0xd4/0x1b0
[   35.933872]  ? selinux_bpf+0xd/0x70
[   35.937532]  __do_sys_bpf+0x6bb/0x21e0
[   35.941570]  ? find_held_lock+0x2d/0x90
[   35.945687]  ? vfs_write+0x150/0x220
[   35.949586]  do_syscall_64+0x2d/0x40
[   35.953443]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fix this by calling migrate_disable() before smp_processor_id().

Fixes: 1b4d60ec16 ("bpf: Enable BPF_PROG_TEST_RUN for raw_tracepoint")
Reported-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2020-09-30 08:34:08 -07:00

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// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2017 Facebook
*/
#include <linux/bpf.h>
#include <linux/slab.h>
#include <linux/vmalloc.h>
#include <linux/etherdevice.h>
#include <linux/filter.h>
#include <linux/sched/signal.h>
#include <net/bpf_sk_storage.h>
#include <net/sock.h>
#include <net/tcp.h>
#include <linux/error-injection.h>
#include <linux/smp.h>
#define CREATE_TRACE_POINTS
#include <trace/events/bpf_test_run.h>
static int bpf_test_run(struct bpf_prog *prog, void *ctx, u32 repeat,
u32 *retval, u32 *time, bool xdp)
{
struct bpf_cgroup_storage *storage[MAX_BPF_CGROUP_STORAGE_TYPE] = { NULL };
enum bpf_cgroup_storage_type stype;
u64 time_start, time_spent = 0;
int ret = 0;
u32 i;
for_each_cgroup_storage_type(stype) {
storage[stype] = bpf_cgroup_storage_alloc(prog, stype);
if (IS_ERR(storage[stype])) {
storage[stype] = NULL;
for_each_cgroup_storage_type(stype)
bpf_cgroup_storage_free(storage[stype]);
return -ENOMEM;
}
}
if (!repeat)
repeat = 1;
rcu_read_lock();
migrate_disable();
time_start = ktime_get_ns();
for (i = 0; i < repeat; i++) {
bpf_cgroup_storage_set(storage);
if (xdp)
*retval = bpf_prog_run_xdp(prog, ctx);
else
*retval = BPF_PROG_RUN(prog, ctx);
if (signal_pending(current)) {
ret = -EINTR;
break;
}
if (need_resched()) {
time_spent += ktime_get_ns() - time_start;
migrate_enable();
rcu_read_unlock();
cond_resched();
rcu_read_lock();
migrate_disable();
time_start = ktime_get_ns();
}
}
time_spent += ktime_get_ns() - time_start;
migrate_enable();
rcu_read_unlock();
do_div(time_spent, repeat);
*time = time_spent > U32_MAX ? U32_MAX : (u32)time_spent;
for_each_cgroup_storage_type(stype)
bpf_cgroup_storage_free(storage[stype]);
return ret;
}
static int bpf_test_finish(const union bpf_attr *kattr,
union bpf_attr __user *uattr, const void *data,
u32 size, u32 retval, u32 duration)
{
void __user *data_out = u64_to_user_ptr(kattr->test.data_out);
int err = -EFAULT;
u32 copy_size = size;
/* Clamp copy if the user has provided a size hint, but copy the full
* buffer if not to retain old behaviour.
*/
if (kattr->test.data_size_out &&
copy_size > kattr->test.data_size_out) {
copy_size = kattr->test.data_size_out;
err = -ENOSPC;
}
if (data_out && copy_to_user(data_out, data, copy_size))
goto out;
if (copy_to_user(&uattr->test.data_size_out, &size, sizeof(size)))
goto out;
if (copy_to_user(&uattr->test.retval, &retval, sizeof(retval)))
goto out;
if (copy_to_user(&uattr->test.duration, &duration, sizeof(duration)))
goto out;
if (err != -ENOSPC)
err = 0;
out:
trace_bpf_test_finish(&err);
return err;
}
/* Integer types of various sizes and pointer combinations cover variety of
* architecture dependent calling conventions. 7+ can be supported in the
* future.
*/
__diag_push();
__diag_ignore(GCC, 8, "-Wmissing-prototypes",
"Global functions as their definitions will be in vmlinux BTF");
int noinline bpf_fentry_test1(int a)
{
return a + 1;
}
int noinline bpf_fentry_test2(int a, u64 b)
{
return a + b;
}
int noinline bpf_fentry_test3(char a, int b, u64 c)
{
return a + b + c;
}
int noinline bpf_fentry_test4(void *a, char b, int c, u64 d)
{
return (long)a + b + c + d;
}
int noinline bpf_fentry_test5(u64 a, void *b, short c, int d, u64 e)
{
return a + (long)b + c + d + e;
}
int noinline bpf_fentry_test6(u64 a, void *b, short c, int d, void *e, u64 f)
{
return a + (long)b + c + d + (long)e + f;
}
struct bpf_fentry_test_t {
struct bpf_fentry_test_t *a;
};
int noinline bpf_fentry_test7(struct bpf_fentry_test_t *arg)
{
return (long)arg;
}
int noinline bpf_fentry_test8(struct bpf_fentry_test_t *arg)
{
return (long)arg->a;
}
int noinline bpf_modify_return_test(int a, int *b)
{
*b += 1;
return a + *b;
}
__diag_pop();
ALLOW_ERROR_INJECTION(bpf_modify_return_test, ERRNO);
static void *bpf_test_init(const union bpf_attr *kattr, u32 size,
u32 headroom, u32 tailroom)
{
void __user *data_in = u64_to_user_ptr(kattr->test.data_in);
u32 user_size = kattr->test.data_size_in;
void *data;
if (size < ETH_HLEN || size > PAGE_SIZE - headroom - tailroom)
return ERR_PTR(-EINVAL);
if (user_size > size)
return ERR_PTR(-EMSGSIZE);
data = kzalloc(size + headroom + tailroom, GFP_USER);
if (!data)
return ERR_PTR(-ENOMEM);
if (copy_from_user(data + headroom, data_in, user_size)) {
kfree(data);
return ERR_PTR(-EFAULT);
}
return data;
}
int bpf_prog_test_run_tracing(struct bpf_prog *prog,
const union bpf_attr *kattr,
union bpf_attr __user *uattr)
{
struct bpf_fentry_test_t arg = {};
u16 side_effect = 0, ret = 0;
int b = 2, err = -EFAULT;
u32 retval = 0;
if (kattr->test.flags || kattr->test.cpu)
return -EINVAL;
switch (prog->expected_attach_type) {
case BPF_TRACE_FENTRY:
case BPF_TRACE_FEXIT:
if (bpf_fentry_test1(1) != 2 ||
bpf_fentry_test2(2, 3) != 5 ||
bpf_fentry_test3(4, 5, 6) != 15 ||
bpf_fentry_test4((void *)7, 8, 9, 10) != 34 ||
bpf_fentry_test5(11, (void *)12, 13, 14, 15) != 65 ||
bpf_fentry_test6(16, (void *)17, 18, 19, (void *)20, 21) != 111 ||
bpf_fentry_test7((struct bpf_fentry_test_t *)0) != 0 ||
bpf_fentry_test8(&arg) != 0)
goto out;
break;
case BPF_MODIFY_RETURN:
ret = bpf_modify_return_test(1, &b);
if (b != 2)
side_effect = 1;
break;
default:
goto out;
}
retval = ((u32)side_effect << 16) | ret;
if (copy_to_user(&uattr->test.retval, &retval, sizeof(retval)))
goto out;
err = 0;
out:
trace_bpf_test_finish(&err);
return err;
}
struct bpf_raw_tp_test_run_info {
struct bpf_prog *prog;
void *ctx;
u32 retval;
};
static void
__bpf_prog_test_run_raw_tp(void *data)
{
struct bpf_raw_tp_test_run_info *info = data;
rcu_read_lock();
info->retval = BPF_PROG_RUN(info->prog, info->ctx);
rcu_read_unlock();
}
int bpf_prog_test_run_raw_tp(struct bpf_prog *prog,
const union bpf_attr *kattr,
union bpf_attr __user *uattr)
{
void __user *ctx_in = u64_to_user_ptr(kattr->test.ctx_in);
__u32 ctx_size_in = kattr->test.ctx_size_in;
struct bpf_raw_tp_test_run_info info;
int cpu = kattr->test.cpu, err = 0;
int current_cpu;
/* doesn't support data_in/out, ctx_out, duration, or repeat */
if (kattr->test.data_in || kattr->test.data_out ||
kattr->test.ctx_out || kattr->test.duration ||
kattr->test.repeat)
return -EINVAL;
if (ctx_size_in < prog->aux->max_ctx_offset)
return -EINVAL;
if ((kattr->test.flags & BPF_F_TEST_RUN_ON_CPU) == 0 && cpu != 0)
return -EINVAL;
if (ctx_size_in) {
info.ctx = kzalloc(ctx_size_in, GFP_USER);
if (!info.ctx)
return -ENOMEM;
if (copy_from_user(info.ctx, ctx_in, ctx_size_in)) {
err = -EFAULT;
goto out;
}
} else {
info.ctx = NULL;
}
info.prog = prog;
current_cpu = get_cpu();
if ((kattr->test.flags & BPF_F_TEST_RUN_ON_CPU) == 0 ||
cpu == current_cpu) {
__bpf_prog_test_run_raw_tp(&info);
} else if (cpu >= nr_cpu_ids || !cpu_online(cpu)) {
/* smp_call_function_single() also checks cpu_online()
* after csd_lock(). However, since cpu is from user
* space, let's do an extra quick check to filter out
* invalid value before smp_call_function_single().
*/
err = -ENXIO;
} else {
err = smp_call_function_single(cpu, __bpf_prog_test_run_raw_tp,
&info, 1);
}
put_cpu();
if (!err &&
copy_to_user(&uattr->test.retval, &info.retval, sizeof(u32)))
err = -EFAULT;
out:
kfree(info.ctx);
return err;
}
static void *bpf_ctx_init(const union bpf_attr *kattr, u32 max_size)
{
void __user *data_in = u64_to_user_ptr(kattr->test.ctx_in);
void __user *data_out = u64_to_user_ptr(kattr->test.ctx_out);
u32 size = kattr->test.ctx_size_in;
void *data;
int err;
if (!data_in && !data_out)
return NULL;
data = kzalloc(max_size, GFP_USER);
if (!data)
return ERR_PTR(-ENOMEM);
if (data_in) {
err = bpf_check_uarg_tail_zero(data_in, max_size, size);
if (err) {
kfree(data);
return ERR_PTR(err);
}
size = min_t(u32, max_size, size);
if (copy_from_user(data, data_in, size)) {
kfree(data);
return ERR_PTR(-EFAULT);
}
}
return data;
}
static int bpf_ctx_finish(const union bpf_attr *kattr,
union bpf_attr __user *uattr, const void *data,
u32 size)
{
void __user *data_out = u64_to_user_ptr(kattr->test.ctx_out);
int err = -EFAULT;
u32 copy_size = size;
if (!data || !data_out)
return 0;
if (copy_size > kattr->test.ctx_size_out) {
copy_size = kattr->test.ctx_size_out;
err = -ENOSPC;
}
if (copy_to_user(data_out, data, copy_size))
goto out;
if (copy_to_user(&uattr->test.ctx_size_out, &size, sizeof(size)))
goto out;
if (err != -ENOSPC)
err = 0;
out:
return err;
}
/**
* range_is_zero - test whether buffer is initialized
* @buf: buffer to check
* @from: check from this position
* @to: check up until (excluding) this position
*
* This function returns true if the there is a non-zero byte
* in the buf in the range [from,to).
*/
static inline bool range_is_zero(void *buf, size_t from, size_t to)
{
return !memchr_inv((u8 *)buf + from, 0, to - from);
}
static int convert___skb_to_skb(struct sk_buff *skb, struct __sk_buff *__skb)
{
struct qdisc_skb_cb *cb = (struct qdisc_skb_cb *)skb->cb;
if (!__skb)
return 0;
/* make sure the fields we don't use are zeroed */
if (!range_is_zero(__skb, 0, offsetof(struct __sk_buff, mark)))
return -EINVAL;
/* mark is allowed */
if (!range_is_zero(__skb, offsetofend(struct __sk_buff, mark),
offsetof(struct __sk_buff, priority)))
return -EINVAL;
/* priority is allowed */
if (!range_is_zero(__skb, offsetofend(struct __sk_buff, priority),
offsetof(struct __sk_buff, ifindex)))
return -EINVAL;
/* ifindex is allowed */
if (!range_is_zero(__skb, offsetofend(struct __sk_buff, ifindex),
offsetof(struct __sk_buff, cb)))
return -EINVAL;
/* cb is allowed */
if (!range_is_zero(__skb, offsetofend(struct __sk_buff, cb),
offsetof(struct __sk_buff, tstamp)))
return -EINVAL;
/* tstamp is allowed */
/* wire_len is allowed */
/* gso_segs is allowed */
if (!range_is_zero(__skb, offsetofend(struct __sk_buff, gso_segs),
offsetof(struct __sk_buff, gso_size)))
return -EINVAL;
/* gso_size is allowed */
if (!range_is_zero(__skb, offsetofend(struct __sk_buff, gso_size),
sizeof(struct __sk_buff)))
return -EINVAL;
skb->mark = __skb->mark;
skb->priority = __skb->priority;
skb->tstamp = __skb->tstamp;
memcpy(&cb->data, __skb->cb, QDISC_CB_PRIV_LEN);
if (__skb->wire_len == 0) {
cb->pkt_len = skb->len;
} else {
if (__skb->wire_len < skb->len ||
__skb->wire_len > GSO_MAX_SIZE)
return -EINVAL;
cb->pkt_len = __skb->wire_len;
}
if (__skb->gso_segs > GSO_MAX_SEGS)
return -EINVAL;
skb_shinfo(skb)->gso_segs = __skb->gso_segs;
skb_shinfo(skb)->gso_size = __skb->gso_size;
return 0;
}
static void convert_skb_to___skb(struct sk_buff *skb, struct __sk_buff *__skb)
{
struct qdisc_skb_cb *cb = (struct qdisc_skb_cb *)skb->cb;
if (!__skb)
return;
__skb->mark = skb->mark;
__skb->priority = skb->priority;
__skb->ifindex = skb->dev->ifindex;
__skb->tstamp = skb->tstamp;
memcpy(__skb->cb, &cb->data, QDISC_CB_PRIV_LEN);
__skb->wire_len = cb->pkt_len;
__skb->gso_segs = skb_shinfo(skb)->gso_segs;
}
int bpf_prog_test_run_skb(struct bpf_prog *prog, const union bpf_attr *kattr,
union bpf_attr __user *uattr)
{
bool is_l2 = false, is_direct_pkt_access = false;
struct net *net = current->nsproxy->net_ns;
struct net_device *dev = net->loopback_dev;
u32 size = kattr->test.data_size_in;
u32 repeat = kattr->test.repeat;
struct __sk_buff *ctx = NULL;
u32 retval, duration;
int hh_len = ETH_HLEN;
struct sk_buff *skb;
struct sock *sk;
void *data;
int ret;
if (kattr->test.flags || kattr->test.cpu)
return -EINVAL;
data = bpf_test_init(kattr, size, NET_SKB_PAD + NET_IP_ALIGN,
SKB_DATA_ALIGN(sizeof(struct skb_shared_info)));
if (IS_ERR(data))
return PTR_ERR(data);
ctx = bpf_ctx_init(kattr, sizeof(struct __sk_buff));
if (IS_ERR(ctx)) {
kfree(data);
return PTR_ERR(ctx);
}
switch (prog->type) {
case BPF_PROG_TYPE_SCHED_CLS:
case BPF_PROG_TYPE_SCHED_ACT:
is_l2 = true;
fallthrough;
case BPF_PROG_TYPE_LWT_IN:
case BPF_PROG_TYPE_LWT_OUT:
case BPF_PROG_TYPE_LWT_XMIT:
is_direct_pkt_access = true;
break;
default:
break;
}
sk = kzalloc(sizeof(struct sock), GFP_USER);
if (!sk) {
kfree(data);
kfree(ctx);
return -ENOMEM;
}
sock_net_set(sk, net);
sock_init_data(NULL, sk);
skb = build_skb(data, 0);
if (!skb) {
kfree(data);
kfree(ctx);
kfree(sk);
return -ENOMEM;
}
skb->sk = sk;
skb_reserve(skb, NET_SKB_PAD + NET_IP_ALIGN);
__skb_put(skb, size);
if (ctx && ctx->ifindex > 1) {
dev = dev_get_by_index(net, ctx->ifindex);
if (!dev) {
ret = -ENODEV;
goto out;
}
}
skb->protocol = eth_type_trans(skb, dev);
skb_reset_network_header(skb);
switch (skb->protocol) {
case htons(ETH_P_IP):
sk->sk_family = AF_INET;
if (sizeof(struct iphdr) <= skb_headlen(skb)) {
sk->sk_rcv_saddr = ip_hdr(skb)->saddr;
sk->sk_daddr = ip_hdr(skb)->daddr;
}
break;
#if IS_ENABLED(CONFIG_IPV6)
case htons(ETH_P_IPV6):
sk->sk_family = AF_INET6;
if (sizeof(struct ipv6hdr) <= skb_headlen(skb)) {
sk->sk_v6_rcv_saddr = ipv6_hdr(skb)->saddr;
sk->sk_v6_daddr = ipv6_hdr(skb)->daddr;
}
break;
#endif
default:
break;
}
if (is_l2)
__skb_push(skb, hh_len);
if (is_direct_pkt_access)
bpf_compute_data_pointers(skb);
ret = convert___skb_to_skb(skb, ctx);
if (ret)
goto out;
ret = bpf_test_run(prog, skb, repeat, &retval, &duration, false);
if (ret)
goto out;
if (!is_l2) {
if (skb_headroom(skb) < hh_len) {
int nhead = HH_DATA_ALIGN(hh_len - skb_headroom(skb));
if (pskb_expand_head(skb, nhead, 0, GFP_USER)) {
ret = -ENOMEM;
goto out;
}
}
memset(__skb_push(skb, hh_len), 0, hh_len);
}
convert_skb_to___skb(skb, ctx);
size = skb->len;
/* bpf program can never convert linear skb to non-linear */
if (WARN_ON_ONCE(skb_is_nonlinear(skb)))
size = skb_headlen(skb);
ret = bpf_test_finish(kattr, uattr, skb->data, size, retval, duration);
if (!ret)
ret = bpf_ctx_finish(kattr, uattr, ctx,
sizeof(struct __sk_buff));
out:
if (dev && dev != net->loopback_dev)
dev_put(dev);
kfree_skb(skb);
bpf_sk_storage_free(sk);
kfree(sk);
kfree(ctx);
return ret;
}
int bpf_prog_test_run_xdp(struct bpf_prog *prog, const union bpf_attr *kattr,
union bpf_attr __user *uattr)
{
u32 tailroom = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
u32 headroom = XDP_PACKET_HEADROOM;
u32 size = kattr->test.data_size_in;
u32 repeat = kattr->test.repeat;
struct netdev_rx_queue *rxqueue;
struct xdp_buff xdp = {};
u32 retval, duration;
u32 max_data_sz;
void *data;
int ret;
if (kattr->test.ctx_in || kattr->test.ctx_out)
return -EINVAL;
/* XDP have extra tailroom as (most) drivers use full page */
max_data_sz = 4096 - headroom - tailroom;
data = bpf_test_init(kattr, max_data_sz, headroom, tailroom);
if (IS_ERR(data))
return PTR_ERR(data);
xdp.data_hard_start = data;
xdp.data = data + headroom;
xdp.data_meta = xdp.data;
xdp.data_end = xdp.data + size;
xdp.frame_sz = headroom + max_data_sz + tailroom;
rxqueue = __netif_get_rx_queue(current->nsproxy->net_ns->loopback_dev, 0);
xdp.rxq = &rxqueue->xdp_rxq;
bpf_prog_change_xdp(NULL, prog);
ret = bpf_test_run(prog, &xdp, repeat, &retval, &duration, true);
if (ret)
goto out;
if (xdp.data != data + headroom || xdp.data_end != xdp.data + size)
size = xdp.data_end - xdp.data;
ret = bpf_test_finish(kattr, uattr, xdp.data, size, retval, duration);
out:
bpf_prog_change_xdp(prog, NULL);
kfree(data);
return ret;
}
static int verify_user_bpf_flow_keys(struct bpf_flow_keys *ctx)
{
/* make sure the fields we don't use are zeroed */
if (!range_is_zero(ctx, 0, offsetof(struct bpf_flow_keys, flags)))
return -EINVAL;
/* flags is allowed */
if (!range_is_zero(ctx, offsetofend(struct bpf_flow_keys, flags),
sizeof(struct bpf_flow_keys)))
return -EINVAL;
return 0;
}
int bpf_prog_test_run_flow_dissector(struct bpf_prog *prog,
const union bpf_attr *kattr,
union bpf_attr __user *uattr)
{
u32 size = kattr->test.data_size_in;
struct bpf_flow_dissector ctx = {};
u32 repeat = kattr->test.repeat;
struct bpf_flow_keys *user_ctx;
struct bpf_flow_keys flow_keys;
u64 time_start, time_spent = 0;
const struct ethhdr *eth;
unsigned int flags = 0;
u32 retval, duration;
void *data;
int ret;
u32 i;
if (prog->type != BPF_PROG_TYPE_FLOW_DISSECTOR)
return -EINVAL;
if (kattr->test.flags || kattr->test.cpu)
return -EINVAL;
if (size < ETH_HLEN)
return -EINVAL;
data = bpf_test_init(kattr, size, 0, 0);
if (IS_ERR(data))
return PTR_ERR(data);
eth = (struct ethhdr *)data;
if (!repeat)
repeat = 1;
user_ctx = bpf_ctx_init(kattr, sizeof(struct bpf_flow_keys));
if (IS_ERR(user_ctx)) {
kfree(data);
return PTR_ERR(user_ctx);
}
if (user_ctx) {
ret = verify_user_bpf_flow_keys(user_ctx);
if (ret)
goto out;
flags = user_ctx->flags;
}
ctx.flow_keys = &flow_keys;
ctx.data = data;
ctx.data_end = (__u8 *)data + size;
rcu_read_lock();
preempt_disable();
time_start = ktime_get_ns();
for (i = 0; i < repeat; i++) {
retval = bpf_flow_dissect(prog, &ctx, eth->h_proto, ETH_HLEN,
size, flags);
if (signal_pending(current)) {
preempt_enable();
rcu_read_unlock();
ret = -EINTR;
goto out;
}
if (need_resched()) {
time_spent += ktime_get_ns() - time_start;
preempt_enable();
rcu_read_unlock();
cond_resched();
rcu_read_lock();
preempt_disable();
time_start = ktime_get_ns();
}
}
time_spent += ktime_get_ns() - time_start;
preempt_enable();
rcu_read_unlock();
do_div(time_spent, repeat);
duration = time_spent > U32_MAX ? U32_MAX : (u32)time_spent;
ret = bpf_test_finish(kattr, uattr, &flow_keys, sizeof(flow_keys),
retval, duration);
if (!ret)
ret = bpf_ctx_finish(kattr, uattr, user_ctx,
sizeof(struct bpf_flow_keys));
out:
kfree(user_ctx);
kfree(data);
return ret;
}
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