Hi,
On 12/2/2021 1:42 AM, Alexei Starovoitov wrote:
> On Tue, Nov 30, 2021 at 11:19 PM Hou Tao <houtao1@xxxxxxxxxx> wrote:
>> BPF_LOG_KERNEL is only used internally, so disallow bpf_btf_load()
>> to set log level as BPF_LOG_KERNEL. The same checking has already
>> been done in bpf_check(), so factor out a helper to check the
>> validity of log attributes and use it in both places.
>>
>>
snip
>> - ret = -EINVAL;
>> /* log attributes have to be sane */
>> - if (log->len_total < 128 || log->len_total > UINT_MAX >> 2 ||
>> - !log->level || !log->ubuf || log->level & ~BPF_LOG_MASK)
>> + if (!bpf_verifier_log_attr_valid(log, UINT_MAX >> 2)) {
>> + ret = -EINVAL;
> It's actually quite bad that we have this discrepancy in limits.
> I've already sent a patch to make them the same.
> It was a pain to debug.
> https://lore.kernel.org/bpf/20211124060209.493-7-alexei.starovoitov@xxxxxxxxx/
> "
> Otherwise tools that progressively increase log size and use the same log
> for BTF loading and program loading will be hitting hard to debug EINVAL.
> "
OK. Will send a single patch to handle that based on your patch set.
Regards,
Tao
