323 lines
7.4 KiB
C
323 lines
7.4 KiB
C
|
// SPDX-License-Identifier: GPL-2.0
|
||
|
|
#include <vmlinux.h>
|
||
|
|
#include <bpf/bpf_tracing.h>
|
||
|
|
#include <bpf/bpf_helpers.h>
|
||
|
|
#include <bpf/bpf_core_read.h>
|
||
|
|
#include "bpf_experimental.h"
|
||
|
|
#include "bpf_misc.h"
|
||
|
|
|
||
|
|
struct node_data {
|
||
|
|
long key;
|
||
|
|
long data;
|
||
|
|
struct bpf_rb_node node;
|
||
|
|
};
|
||
|
|
|
||
|
|
#define private(name) SEC(".data." #name) __hidden __attribute__((aligned(8)))
|
||
|
|
private(A) struct bpf_spin_lock glock;
|
||
|
|
private(A) struct bpf_rb_root groot __contains(node_data, node);
|
||
|
|
private(A) struct bpf_rb_root groot2 __contains(node_data, node);
|
||
|
|
|
||
|
|
static bool less(struct bpf_rb_node *a, const struct bpf_rb_node *b)
|
||
|
|
{
|
||
|
|
struct node_data *node_a;
|
||
|
|
struct node_data *node_b;
|
||
|
|
|
||
|
|
node_a = container_of(a, struct node_data, node);
|
||
|
|
node_b = container_of(b, struct node_data, node);
|
||
|
|
|
||
|
|
return node_a->key < node_b->key;
|
||
|
|
}
|
||
|
|
|
||
|
|
SEC("?tc")
|
||
|
|
__failure __msg("bpf_spin_lock at off=16 must be held for bpf_rb_root")
|
||
|
|
long rbtree_api_nolock_add(void *ctx)
|
||
|
|
{
|
||
|
|
struct node_data *n;
|
||
|
|
|
||
|
|
n = bpf_obj_new(typeof(*n));
|
||
|
|
if (!n)
|
||
|
|
return 1;
|
||
|
|
|
||
|
|
bpf_rbtree_add(&groot, &n->node, less);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
SEC("?tc")
|
||
|
|
__failure __msg("bpf_spin_lock at off=16 must be held for bpf_rb_root")
|
||
|
|
long rbtree_api_nolock_remove(void *ctx)
|
||
|
|
{
|
||
|
|
struct node_data *n;
|
||
|
|
|
||
|
|
n = bpf_obj_new(typeof(*n));
|
||
|
|
if (!n)
|
||
|
|
return 1;
|
||
|
|
|
||
|
|
bpf_spin_lock(&glock);
|
||
|
|
bpf_rbtree_add(&groot, &n->node, less);
|
||
|
|
bpf_spin_unlock(&glock);
|
||
|
|
|
||
|
|
bpf_rbtree_remove(&groot, &n->node);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
SEC("?tc")
|
||
|
|
__failure __msg("bpf_spin_lock at off=16 must be held for bpf_rb_root")
|
||
|
|
long rbtree_api_nolock_first(void *ctx)
|
||
|
|
{
|
||
|
|
bpf_rbtree_first(&groot);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
SEC("?tc")
|
||
|
|
__failure __msg("rbtree_remove node input must be non-owning ref")
|
||
|
|
long rbtree_api_remove_unadded_node(void *ctx)
|
||
|
|
{
|
||
|
|
struct node_data *n, *m;
|
||
|
|
struct bpf_rb_node *res;
|
||
|
|
|
||
|
|
n = bpf_obj_new(typeof(*n));
|
||
|
|
if (!n)
|
||
|
|
return 1;
|
||
|
|
|
||
|
|
m = bpf_obj_new(typeof(*m));
|
||
|
|
if (!m) {
|
||
|
|
bpf_obj_drop(n);
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
bpf_spin_lock(&glock);
|
||
|
|
bpf_rbtree_add(&groot, &n->node, less);
|
||
|
|
|
||
|
|
/* This remove should pass verifier */
|
||
|
|
res = bpf_rbtree_remove(&groot, &n->node);
|
||
|
|
n = container_of(res, struct node_data, node);
|
||
|
|
|
||
|
|
/* This remove shouldn't, m isn't in an rbtree */
|
||
|
|
res = bpf_rbtree_remove(&groot, &m->node);
|
||
|
|
m = container_of(res, struct node_data, node);
|
||
|
|
bpf_spin_unlock(&glock);
|
||
|
|
|
||
|
|
if (n)
|
||
|
|
bpf_obj_drop(n);
|
||
|
|
if (m)
|
||
|
|
bpf_obj_drop(m);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
SEC("?tc")
|
||
|
|
__failure __msg("Unreleased reference id=2 alloc_insn=11")
|
||
|
|
long rbtree_api_remove_no_drop(void *ctx)
|
||
|
|
{
|
||
|
|
struct bpf_rb_node *res;
|
||
|
|
struct node_data *n;
|
||
|
|
|
||
|
|
bpf_spin_lock(&glock);
|
||
|
|
res = bpf_rbtree_first(&groot);
|
||
|
|
if (!res)
|
||
|
|
goto unlock_err;
|
||
|
|
|
||
|
|
res = bpf_rbtree_remove(&groot, res);
|
||
|
|
|
||
|
|
n = container_of(res, struct node_data, node);
|
||
|
|
bpf_spin_unlock(&glock);
|
||
|
|
|
||
|
|
/* bpf_obj_drop(n) is missing here */
|
||
|
|
return 0;
|
||
|
|
|
||
|
|
unlock_err:
|
||
|
|
bpf_spin_unlock(&glock);
|
||
|
|
return 1;
|
||
|
|
}
|
||
|
|
|
||
|
|
SEC("?tc")
|
||
|
|
__failure __msg("arg#1 expected pointer to allocated object")
|
||
|
|
long rbtree_api_add_to_multiple_trees(void *ctx)
|
||
|
|
{
|
||
|
|
struct node_data *n;
|
||
|
|
|
||
|
|
n = bpf_obj_new(typeof(*n));
|
||
|
|
if (!n)
|
||
|
|
return 1;
|
||
|
|
|
||
|
|
bpf_spin_lock(&glock);
|
||
|
|
bpf_rbtree_add(&groot, &n->node, less);
|
||
|
|
|
||
|
|
/* This add should fail since n already in groot's tree */
|
||
|
|
bpf_rbtree_add(&groot2, &n->node, less);
|
||
|
|
bpf_spin_unlock(&glock);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
SEC("?tc")
|
||
|
|
__failure __msg("rbtree_remove node input must be non-owning ref")
|
||
|
|
long rbtree_api_add_release_unlock_escape(void *ctx)
|
||
|
|
{
|
||
|
|
struct node_data *n;
|
||
|
|
|
||
|
|
n = bpf_obj_new(typeof(*n));
|
||
|
|
if (!n)
|
||
|
|
return 1;
|
||
|
|
|
||
|
|
bpf_spin_lock(&glock);
|
||
|
|
bpf_rbtree_add(&groot, &n->node, less);
|
||
|
|
bpf_spin_unlock(&glock);
|
||
|
|
|
||
|
|
bpf_spin_lock(&glock);
|
||
|
|
/* After add() in previous critical section, n should be
|
||
|
|
* release_on_unlock and released after previous spin_unlock,
|
||
|
|
* so should not be possible to use it here
|
||
|
|
*/
|
||
|
|
bpf_rbtree_remove(&groot, &n->node);
|
||
|
|
bpf_spin_unlock(&glock);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
SEC("?tc")
|
||
|
|
__failure __msg("rbtree_remove node input must be non-owning ref")
|
||
|
|
long rbtree_api_release_aliasing(void *ctx)
|
||
|
|
{
|
||
|
|
struct node_data *n, *m, *o;
|
||
|
|
struct bpf_rb_node *res;
|
||
|
|
|
||
|
|
n = bpf_obj_new(typeof(*n));
|
||
|
|
if (!n)
|
||
|
|
return 1;
|
||
|
|
|
||
|
|
bpf_spin_lock(&glock);
|
||
|
|
bpf_rbtree_add(&groot, &n->node, less);
|
||
|
|
bpf_spin_unlock(&glock);
|
||
|
|
|
||
|
|
bpf_spin_lock(&glock);
|
||
|
|
|
||
|
|
/* m and o point to the same node,
|
||
|
|
* but verifier doesn't know this
|
||
|
|
*/
|
||
|
|
res = bpf_rbtree_first(&groot);
|
||
|
|
if (!res)
|
||
|
|
return 1;
|
||
|
|
o = container_of(res, struct node_data, node);
|
||
|
|
|
||
|
|
res = bpf_rbtree_first(&groot);
|
||
|
|
if (!res)
|
||
|
|
return 1;
|
||
|
|
m = container_of(res, struct node_data, node);
|
||
|
|
|
||
|
|
bpf_rbtree_remove(&groot, &m->node);
|
||
|
|
/* This second remove shouldn't be possible. Retval of previous
|
||
|
|
* remove returns owning reference to m, which is the same
|
||
|
|
* node o's non-owning ref is pointing at
|
||
|
|
*
|
||
|
|
* In order to preserve property
|
||
|
|
* * owning ref must not be in rbtree
|
||
|
|
* * non-owning ref must be in rbtree
|
||
|
|
*
|
||
|
|
* o's ref must be invalidated after previous remove. Otherwise
|
||
|
|
* we'd have non-owning ref to node that isn't in rbtree, and
|
||
|
|
* verifier wouldn't be able to use type system to prevent remove
|
||
|
|
* of ref that already isn't in any tree. Would have to do runtime
|
||
|
|
* checks in that case.
|
||
|
|
*/
|
||
|
|
bpf_rbtree_remove(&groot, &o->node);
|
||
|
|
|
||
|
|
bpf_spin_unlock(&glock);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
SEC("?tc")
|
||
|
|
__failure __msg("rbtree_remove node input must be non-owning ref")
|
||
|
|
long rbtree_api_first_release_unlock_escape(void *ctx)
|
||
|
|
{
|
||
|
|
struct bpf_rb_node *res;
|
||
|
|
struct node_data *n;
|
||
|
|
|
||
|
|
bpf_spin_lock(&glock);
|
||
|
|
res = bpf_rbtree_first(&groot);
|
||
|
|
if (res)
|
||
|
|
n = container_of(res, struct node_data, node);
|
||
|
|
bpf_spin_unlock(&glock);
|
||
|
|
|
||
|
|
bpf_spin_lock(&glock);
|
||
|
|
/* After first() in previous critical section, n should be
|
||
|
|
* release_on_unlock and released after previous spin_unlock,
|
||
|
|
* so should not be possible to use it here
|
||
|
|
*/
|
||
|
|
bpf_rbtree_remove(&groot, &n->node);
|
||
|
|
bpf_spin_unlock(&glock);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
static bool less__bad_fn_call_add(struct bpf_rb_node *a, const struct bpf_rb_node *b)
|
||
|
|
{
|
||
|
|
struct node_data *node_a;
|
||
|
|
struct node_data *node_b;
|
||
|
|
|
||
|
|
node_a = container_of(a, struct node_data, node);
|
||
|
|
node_b = container_of(b, struct node_data, node);
|
||
|
|
bpf_rbtree_add(&groot, &node_a->node, less);
|
||
|
|
|
||
|
|
return node_a->key < node_b->key;
|
||
|
|
}
|
||
|
|
|
||
|
|
static bool less__bad_fn_call_remove(struct bpf_rb_node *a, const struct bpf_rb_node *b)
|
||
|
|
{
|
||
|
|
struct node_data *node_a;
|
||
|
|
struct node_data *node_b;
|
||
|
|
|
||
|
|
node_a = container_of(a, struct node_data, node);
|
||
|
|
node_b = container_of(b, struct node_data, node);
|
||
|
|
bpf_rbtree_remove(&groot, &node_a->node);
|
||
|
|
|
||
|
|
return node_a->key < node_b->key;
|
||
|
|
}
|
||
|
|
|
||
|
|
static bool less__bad_fn_call_first_unlock_after(struct bpf_rb_node *a, const struct bpf_rb_node *b)
|
||
|
|
{
|
||
|
|
struct node_data *node_a;
|
||
|
|
struct node_data *node_b;
|
||
|
|
|
||
|
|
node_a = container_of(a, struct node_data, node);
|
||
|
|
node_b = container_of(b, struct node_data, node);
|
||
|
|
bpf_rbtree_first(&groot);
|
||
|
|
bpf_spin_unlock(&glock);
|
||
|
|
|
||
|
|
return node_a->key < node_b->key;
|
||
|
|
}
|
||
|
|
|
||
|
|
static __always_inline
|
||
|
|
long add_with_cb(bool (cb)(struct bpf_rb_node *a, const struct bpf_rb_node *b))
|
||
|
|
{
|
||
|
|
struct node_data *n;
|
||
|
|
|
||
|
|
n = bpf_obj_new(typeof(*n));
|
||
|
|
if (!n)
|
||
|
|
return 1;
|
||
|
|
|
||
|
|
bpf_spin_lock(&glock);
|
||
|
|
bpf_rbtree_add(&groot, &n->node, cb);
|
||
|
|
bpf_spin_unlock(&glock);
|
||
|
|
return 0;
|
||
|
|
}
|
||
|
|
|
||
|
|
SEC("?tc")
|
||
|
|
__failure __msg("arg#1 expected pointer to allocated object")
|
||
|
|
long rbtree_api_add_bad_cb_bad_fn_call_add(void *ctx)
|
||
|
|
{
|
||
|
|
return add_with_cb(less__bad_fn_call_add);
|
||
|
|
}
|
||
|
|
|
||
|
|
SEC("?tc")
|
||
|
|
__failure __msg("rbtree_remove not allowed in rbtree cb")
|
||
|
|
long rbtree_api_add_bad_cb_bad_fn_call_remove(void *ctx)
|
||
|
|
{
|
||
|
|
return add_with_cb(less__bad_fn_call_remove);
|
||
|
|
}
|
||
|
|
|
||
|
|
SEC("?tc")
|
||
|
|
__failure __msg("can't spin_{lock,unlock} in rbtree cb")
|
||
|
|
long rbtree_api_add_bad_cb_bad_fn_call_first_unlock_after(void *ctx)
|
||
|
|
{
|
||
|
|
return add_with_cb(less__bad_fn_call_first_unlock_after);
|
||
|
|
}
|
||
|
|
|
||
|
|
char _license[] SEC("license") = "GPL";
|