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selftests/bpf: test cases for __arg_untrusted

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Check usage of __arg_untrusted parameters with PTR_TO_BTF_ID:
- combining __arg_untrusted with other tags is forbidden;
- non-kernel (program local) types for __arg_untrusted are forbidden;
- passing of {trusted, untrusted, map value, scalar value, values with
  variable offset} to untrusted is ok;
- passing of PTR_TO_BTF_ID with a different type to untrusted is ok;
- passing of untrusted to trusted is forbidden.

Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20250704230354.1323244-7-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Eduard Zingerman 2025-07-04 16:03:52 -07:00 committed by Alexei Starovoitov
parent aaa0e57e69
commit 54ac2c9418
1 changed files with 81 additions and 0 deletions
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81
tools/testing/selftests/bpf/progs/verifier_global_ptr_args.c
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@ -179,4 +179,85 @@ int BPF_PROG(trusted_acq_rel, struct task_struct *task, u64 clone_flags)
return subprog_trusted_acq_rel(task);
}
__weak int subprog_untrusted_bad_tags(struct task_struct *task __arg_untrusted __arg_nullable)
{
return task->pid;
}
SEC("tp_btf/sys_enter")
__failure
__msg("arg#0 untrusted cannot be combined with any other tags")
int untrusted_bad_tags(void *ctx)
{
return subprog_untrusted_bad_tags(0);
}
struct local_type_wont_be_accepted {};
__weak int subprog_untrusted_bad_type(struct local_type_wont_be_accepted *p __arg_untrusted)
{
return 0;
}
SEC("tp_btf/sys_enter")
__failure
__msg("arg#0 reference type('STRUCT local_type_wont_be_accepted') has no matches")
int untrusted_bad_type(void *ctx)
{
return subprog_untrusted_bad_type(bpf_rdonly_cast(0, 0));
}
__weak int subprog_untrusted(const volatile struct task_struct *restrict task __arg_untrusted)
{
return task->pid;
}
SEC("tp_btf/sys_enter")
__success
__log_level(2)
__msg("r1 = {{.*}}; {{.*}}R1_w=trusted_ptr_task_struct()")
__msg("Func#1 ('subprog_untrusted') is global and assumed valid.")
__msg("Validating subprog_untrusted() func#1...")
__msg(": R1=untrusted_ptr_task_struct")
int trusted_to_untrusted(void *ctx)
{
return subprog_untrusted(bpf_get_current_task_btf());
}
char mem[16];
u32 off;
SEC("tp_btf/sys_enter")
__success
int anything_to_untrusted(void *ctx)
{
/* untrusted to untrusted */
subprog_untrusted(bpf_core_cast(0, struct task_struct));
/* wrong type to untrusted */
subprog_untrusted((void *)bpf_core_cast(0, struct bpf_verifier_env));
/* map value to untrusted */
subprog_untrusted((void *)mem);
/* scalar to untrusted */
subprog_untrusted(0);
/* variable offset to untrusted (map) */
subprog_untrusted((void *)mem + off);
/* variable offset to untrusted (trusted) */
subprog_untrusted((void *)bpf_get_current_task_btf() + off);
return 0;
}
__weak int subprog_untrusted2(struct task_struct *task __arg_untrusted)
{
return subprog_trusted_task_nullable(task);
}
SEC("tp_btf/sys_enter")
__failure
__msg("R1 type=untrusted_ptr_ expected=ptr_, trusted_ptr_, rcu_ptr_")
__msg("Caller passes invalid args into func#{{.*}} ('subprog_trusted_task_nullable')")
int untrusted_to_trusted(void *ctx)
{
return subprog_untrusted2(bpf_get_current_task_btf());
}
char _license[] SEC("license") = "GPL";