* [PATCH bpf-next] bpf: Check cfi_stubs before registering a struct_ops type.
@ 2024-02-15 2:24 thinker.li
2024-02-15 18:23 ` Martin KaFai Lau
0 siblings, 1 reply; 4+ messages in thread
From: thinker.li @ 2024-02-15 2:24 UTC (permalink / raw
To: bpf, ast, martin.lau, song, kernel-team, andrii
Cc: sinquersw, kuifeng, Kui-Feng Lee
From: Kui-Feng Lee <thinker.li@gmail.com>
Recently, cfi_stubs were introduced. However, existing struct_ops types
that are not in the upstream may not be aware of this, resulting in kernel
crashes. By rejecting struct_ops types that do not provide cfi_stubs during
registration, these crashes can be avoided.
Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
---
kernel/bpf/bpf_struct_ops.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
index 0d7be97a2411..e35958142dce 100644
--- a/kernel/bpf/bpf_struct_ops.c
+++ b/kernel/bpf/bpf_struct_ops.c
@@ -302,6 +302,11 @@ int bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc,
}
sprintf(value_name, "%s%s", VALUE_PREFIX, st_ops->name);
+ if (!st_ops->cfi_stubs) {
+ pr_warn("The struct_ops %s has no cfi_stubs\n", st_ops->name);
+ return -EINVAL;
+ }
+
type_id = btf_find_by_name_kind(btf, st_ops->name,
BTF_KIND_STRUCT);
if (type_id < 0) {
--
2.34.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH bpf-next] bpf: Check cfi_stubs before registering a struct_ops type.
2024-02-15 2:24 [PATCH bpf-next] bpf: Check cfi_stubs before registering a struct_ops type thinker.li
@ 2024-02-15 18:23 ` Martin KaFai Lau
2024-02-15 19:19 ` Kui-Feng Lee
0 siblings, 1 reply; 4+ messages in thread
From: Martin KaFai Lau @ 2024-02-15 18:23 UTC (permalink / raw
To: thinker.li; +Cc: sinquersw, kuifeng, bpf, ast, song, kernel-team, andrii
On 2/14/24 6:24 PM, thinker.li@gmail.com wrote:
> From: Kui-Feng Lee <thinker.li@gmail.com>
>
> Recently, cfi_stubs were introduced. However, existing struct_ops types
> that are not in the upstream may not be aware of this, resulting in kernel
> crashes. By rejecting struct_ops types that do not provide cfi_stubs during
> registration, these crashes can be avoided.
>
> Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
> ---
> kernel/bpf/bpf_struct_ops.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
> index 0d7be97a2411..e35958142dce 100644
> --- a/kernel/bpf/bpf_struct_ops.c
> +++ b/kernel/bpf/bpf_struct_ops.c
> @@ -302,6 +302,11 @@ int bpf_struct_ops_desc_init(struct bpf_struct_ops_desc *st_ops_desc,
> }
> sprintf(value_name, "%s%s", VALUE_PREFIX, st_ops->name);
>
> + if (!st_ops->cfi_stubs) {
How about *(void **)(st_ops->cfi_stubs + moff) ? Does it need a NULL check?
Please add a test.
> + pr_warn("The struct_ops %s has no cfi_stubs\n", st_ops->name);
> + return -EINVAL;
> + }
> +
> type_id = btf_find_by_name_kind(btf, st_ops->name,
> BTF_KIND_STRUCT);
> if (type_id < 0) {
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH bpf-next] bpf: Check cfi_stubs before registering a struct_ops type.
2024-02-15 18:23 ` Martin KaFai Lau
@ 2024-02-15 19:19 ` Kui-Feng Lee
2024-02-15 19:20 ` Kui-Feng Lee
0 siblings, 1 reply; 4+ messages in thread
From: Kui-Feng Lee @ 2024-02-15 19:19 UTC (permalink / raw
To: Martin KaFai Lau, thinker.li; +Cc: kuifeng, bpf, ast, song, kernel-team, andrii
On 2/15/24 10:23, Martin KaFai Lau wrote:
> On 2/14/24 6:24 PM, thinker.li@gmail.com wrote:
>> From: Kui-Feng Lee <thinker.li@gmail.com>
>>
>> Recently, cfi_stubs were introduced. However, existing struct_ops types
>> that are not in the upstream may not be aware of this, resulting in
>> kernel
>> crashes. By rejecting struct_ops types that do not provide cfi_stubs
>> during
>> registration, these crashes can be avoided.
>>
>> Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
>> ---
>> kernel/bpf/bpf_struct_ops.c | 5 +++++
>> 1 file changed, 5 insertions(+)
>>
>> diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
>> index 0d7be97a2411..e35958142dce 100644
>> --- a/kernel/bpf/bpf_struct_ops.c
>> +++ b/kernel/bpf/bpf_struct_ops.c
>> @@ -302,6 +302,11 @@ int bpf_struct_ops_desc_init(struct
>> bpf_struct_ops_desc *st_ops_desc,
>> }
>> sprintf(value_name, "%s%s", VALUE_PREFIX, st_ops->name);
>> + if (!st_ops->cfi_stubs) {
>
> How about *(void **)(st_ops->cfi_stubs + moff) ? Does it need a NULL check?
This NULL check is necessary to prevent the crash but good to have.
>
> Please add a test.
Got it!
>
>> + pr_warn("The struct_ops %s has no cfi_stubs\n", st_ops->name);
>> + return -EINVAL;
>> + }
>> +
>> type_id = btf_find_by_name_kind(btf, st_ops->name,
>> BTF_KIND_STRUCT);
>> if (type_id < 0) {
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH bpf-next] bpf: Check cfi_stubs before registering a struct_ops type.
2024-02-15 19:19 ` Kui-Feng Lee
@ 2024-02-15 19:20 ` Kui-Feng Lee
0 siblings, 0 replies; 4+ messages in thread
From: Kui-Feng Lee @ 2024-02-15 19:20 UTC (permalink / raw
To: Martin KaFai Lau, thinker.li; +Cc: kuifeng, bpf, ast, song, kernel-team, andrii
On 2/15/24 11:19, Kui-Feng Lee wrote:
>
>
> On 2/15/24 10:23, Martin KaFai Lau wrote:
>> On 2/14/24 6:24 PM, thinker.li@gmail.com wrote:
>>> From: Kui-Feng Lee <thinker.li@gmail.com>
>>>
>>> Recently, cfi_stubs were introduced. However, existing struct_ops types
>>> that are not in the upstream may not be aware of this, resulting in
>>> kernel
>>> crashes. By rejecting struct_ops types that do not provide cfi_stubs
>>> during
>>> registration, these crashes can be avoided.
>>>
>>> Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
>>> ---
>>> kernel/bpf/bpf_struct_ops.c | 5 +++++
>>> 1 file changed, 5 insertions(+)
>>>
>>> diff --git a/kernel/bpf/bpf_struct_ops.c b/kernel/bpf/bpf_struct_ops.c
>>> index 0d7be97a2411..e35958142dce 100644
>>> --- a/kernel/bpf/bpf_struct_ops.c
>>> +++ b/kernel/bpf/bpf_struct_ops.c
>>> @@ -302,6 +302,11 @@ int bpf_struct_ops_desc_init(struct
>>> bpf_struct_ops_desc *st_ops_desc,
>>> }
>>> sprintf(value_name, "%s%s", VALUE_PREFIX, st_ops->name);
>>> + if (!st_ops->cfi_stubs) {
>>
>> How about *(void **)(st_ops->cfi_stubs + moff) ? Does it need a NULL
>> check?
>
> This NULL check is necessary to prevent the crash but good to have.
^^^ I mean "not necessary"
>
>>
>> Please add a test.
>
> Got it!
>
>>
>>> + pr_warn("The struct_ops %s has no cfi_stubs\n", st_ops->name);
>>> + return -EINVAL;
>>> + }
>>> +
>>> type_id = btf_find_by_name_kind(btf, st_ops->name,
>>> BTF_KIND_STRUCT);
>>> if (type_id < 0) {
>>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-02-15 19:20 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2024-02-15 2:24 [PATCH bpf-next] bpf: Check cfi_stubs before registering a struct_ops type thinker.li
2024-02-15 18:23 ` Martin KaFai Lau
2024-02-15 19:19 ` Kui-Feng Lee
2024-02-15 19:20 ` Kui-Feng Lee
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