1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2023 Meta Platforms, Inc. and affiliates. */
3
4 #include <vmlinux.h>
5 #include <bpf/bpf_tracing.h>
6 #include <bpf/bpf_helpers.h>
7 #include "bpf_misc.h"
8
9 #include "cpumask_common.h"
10
11 char _license[] SEC("license") = "GPL";
12
13 /* Prototype for all of the program trace events below:
14 *
15 * TRACE_EVENT(task_newtask,
16 * TP_PROTO(struct task_struct *p, u64 clone_flags)
17 */
18
19 SEC("tp_btf/task_newtask")
20 __failure __msg("Unreleased reference")
BPF_PROG(test_alloc_no_release,struct task_struct * task,u64 clone_flags)21 int BPF_PROG(test_alloc_no_release, struct task_struct *task, u64 clone_flags)
22 {
23 struct bpf_cpumask *cpumask;
24
25 cpumask = create_cpumask();
26 __sink(cpumask);
27
28 /* cpumask is never released. */
29 return 0;
30 }
31
32 SEC("tp_btf/task_newtask")
33 __failure __msg("NULL pointer passed to trusted arg0")
BPF_PROG(test_alloc_double_release,struct task_struct * task,u64 clone_flags)34 int BPF_PROG(test_alloc_double_release, struct task_struct *task, u64 clone_flags)
35 {
36 struct bpf_cpumask *cpumask;
37
38 cpumask = create_cpumask();
39
40 /* cpumask is released twice. */
41 bpf_cpumask_release(cpumask);
42 bpf_cpumask_release(cpumask);
43
44 return 0;
45 }
46
47 SEC("tp_btf/task_newtask")
48 __failure __msg("must be referenced")
BPF_PROG(test_acquire_wrong_cpumask,struct task_struct * task,u64 clone_flags)49 int BPF_PROG(test_acquire_wrong_cpumask, struct task_struct *task, u64 clone_flags)
50 {
51 struct bpf_cpumask *cpumask;
52
53 /* Can't acquire a non-struct bpf_cpumask. */
54 cpumask = bpf_cpumask_acquire((struct bpf_cpumask *)task->cpus_ptr);
55 __sink(cpumask);
56
57 return 0;
58 }
59
60 SEC("tp_btf/task_newtask")
61 __failure __msg("bpf_cpumask_set_cpu args#1 expected pointer to STRUCT bpf_cpumask")
BPF_PROG(test_mutate_cpumask,struct task_struct * task,u64 clone_flags)62 int BPF_PROG(test_mutate_cpumask, struct task_struct *task, u64 clone_flags)
63 {
64 struct bpf_cpumask *cpumask;
65
66 /* Can't set the CPU of a non-struct bpf_cpumask. */
67 bpf_cpumask_set_cpu(0, (struct bpf_cpumask *)task->cpus_ptr);
68 __sink(cpumask);
69
70 return 0;
71 }
72
73 SEC("tp_btf/task_newtask")
74 __failure __msg("Unreleased reference")
BPF_PROG(test_insert_remove_no_release,struct task_struct * task,u64 clone_flags)75 int BPF_PROG(test_insert_remove_no_release, struct task_struct *task, u64 clone_flags)
76 {
77 struct bpf_cpumask *cpumask;
78 struct __cpumask_map_value *v;
79
80 cpumask = create_cpumask();
81 if (!cpumask)
82 return 0;
83
84 if (cpumask_map_insert(cpumask))
85 return 0;
86
87 v = cpumask_map_value_lookup();
88 if (!v)
89 return 0;
90
91 cpumask = bpf_kptr_xchg(&v->cpumask, NULL);
92
93 /* cpumask is never released. */
94 return 0;
95 }
96
97 SEC("tp_btf/task_newtask")
98 __failure __msg("NULL pointer passed to trusted arg0")
BPF_PROG(test_cpumask_null,struct task_struct * task,u64 clone_flags)99 int BPF_PROG(test_cpumask_null, struct task_struct *task, u64 clone_flags)
100 {
101 /* NULL passed to KF_TRUSTED_ARGS kfunc. */
102 bpf_cpumask_empty(NULL);
103
104 return 0;
105 }
106
107 SEC("tp_btf/task_newtask")
108 __failure __msg("R2 must be a rcu pointer")
BPF_PROG(test_global_mask_out_of_rcu,struct task_struct * task,u64 clone_flags)109 int BPF_PROG(test_global_mask_out_of_rcu, struct task_struct *task, u64 clone_flags)
110 {
111 struct bpf_cpumask *local, *prev;
112
113 local = create_cpumask();
114 if (!local)
115 return 0;
116
117 prev = bpf_kptr_xchg(&global_mask, local);
118 if (prev) {
119 bpf_cpumask_release(prev);
120 err = 3;
121 return 0;
122 }
123
124 bpf_rcu_read_lock();
125 local = global_mask;
126 if (!local) {
127 err = 4;
128 bpf_rcu_read_unlock();
129 return 0;
130 }
131
132 bpf_rcu_read_unlock();
133
134 /* RCU region is exited before calling KF_RCU kfunc. */
135
136 bpf_cpumask_test_cpu(0, (const struct cpumask *)local);
137
138 return 0;
139 }
140
141 SEC("tp_btf/task_newtask")
142 __failure __msg("NULL pointer passed to trusted arg1")
BPF_PROG(test_global_mask_no_null_check,struct task_struct * task,u64 clone_flags)143 int BPF_PROG(test_global_mask_no_null_check, struct task_struct *task, u64 clone_flags)
144 {
145 struct bpf_cpumask *local, *prev;
146
147 local = create_cpumask();
148 if (!local)
149 return 0;
150
151 prev = bpf_kptr_xchg(&global_mask, local);
152 if (prev) {
153 bpf_cpumask_release(prev);
154 err = 3;
155 return 0;
156 }
157
158 bpf_rcu_read_lock();
159 local = global_mask;
160
161 /* No NULL check is performed on global cpumask kptr. */
162 bpf_cpumask_test_cpu(0, (const struct cpumask *)local);
163
164 bpf_rcu_read_unlock();
165
166 return 0;
167 }
168
169 SEC("tp_btf/task_newtask")
170 __failure __msg("Possibly NULL pointer passed to helper arg2")
BPF_PROG(test_global_mask_rcu_no_null_check,struct task_struct * task,u64 clone_flags)171 int BPF_PROG(test_global_mask_rcu_no_null_check, struct task_struct *task, u64 clone_flags)
172 {
173 struct bpf_cpumask *prev, *curr;
174
175 curr = bpf_cpumask_create();
176 if (!curr)
177 return 0;
178
179 prev = bpf_kptr_xchg(&global_mask, curr);
180 if (prev)
181 bpf_cpumask_release(prev);
182
183 bpf_rcu_read_lock();
184 curr = global_mask;
185 /* PTR_TO_BTF_ID | PTR_MAYBE_NULL | MEM_RCU passed to bpf_kptr_xchg() */
186 prev = bpf_kptr_xchg(&global_mask, curr);
187 bpf_rcu_read_unlock();
188 if (prev)
189 bpf_cpumask_release(prev);
190
191 return 0;
192 }
193