[PATCH -next, v2 1/2] audit: fix possible null-pointer dereference in audit_filter_rules

[cuigaosheng]

Thanks for your review, and i have droped the redundant commit message 
and add a Fixes tag to the patch.

https://patchwork.kernel.org/project/linux-audit/patch/20211016072351.237745-2-cuigaosheng1@huawei.com/ 
<https://patchwork.kernel.org/project/linux-audit/patch/20211016072351.237745-2-cuigaosheng1@huawei.com/>

Gaosheng.

在 2021/10/14 5:12, Paul Moore 写道:
> On Wed, Oct 13, 2021 at 5:10 AM Gaosheng Cui <cuigaosheng1 at huawei.com> wrote:
>> Fix this possible null-pointer dereference in audit_filter_rules.
> Thanks for fixing this, just a couple of small comments:
>
> I think you can drop the description text below here, the code snippet
> is just a duplicate of the code and the error message is pretty
> obvious.
>
>> If ctx is null, a null-pointer dereference will occur:
>>      case AUDIT_SADDR_FAM:
>>          if (ctx->sockaddr)
>>                  ...
>>          break;
>>
>> audit_filter_rules() error: we previously assumed 'ctx' could be null
>>
>> Reported-by: kernel test robot <lkp at intel.com>
>> Reported-by: Dan Carpenter <dan.carpenter at oracle.com>
>> Signed-off-by: Gaosheng Cui <cuigaosheng1 at huawei.com>
> I would also add a Fixes tag, for example:
>
> Fixes: bf361231c295 ("audit: add saddr_fam filter field")
>
>> ---
>>   kernel/auditsc.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/kernel/auditsc.c b/kernel/auditsc.c
>> index 4ba3b8573ff4..42d4a4320526 100644
>> --- a/kernel/auditsc.c
>> +++ b/kernel/auditsc.c
>> @@ -647,7 +647,7 @@ static int audit_filter_rules(struct task_struct *tsk,
>>                          result = audit_comparator(audit_loginuid_set(tsk), f->op, f->val);
>>                          break;
>>                  case AUDIT_SADDR_FAM:
>> -                       if (ctx->sockaddr)
>> +                       if (ctx && ctx->sockaddr)
>>                                  result = audit_comparator(ctx->sockaddr->ss_family,
>>                                                            f->op, f->val);
>>                          break;
>> --
>> 2.30.0