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SubjectRe: [RFC PATCH] Security: ignore private inode from security_file_receive
Hello,

On 2015년 04월 16일 22:48, Stephen Smalley wrote:
> On 04/16/2015 09:40 AM, Seung-Woo Kim wrote:
>> The dma-buf fd from anon_inode can be shared across processes, but
>> there is no way to set security permission for the fd. So this
>> patch fix just to ignore private inode from security_file_receive.
>>
>> Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
>> ---
>>
>> If security like smack is enabled, the dmabuf fd can not be shared between
>> processes via unix domain socket. I am not familiar with security, so I am
>> not sure that this kind of patch can be acceptable.
>>
>> Is there other option to share dmabuf fd via socket with security check?
>>
>> Best Regards,
>> - Seung-Woo Kim
>>
>> ---
>> security/security.c | 3 +++
>> 1 files changed, 3 insertions(+), 0 deletions(-)
>>
>> diff --git a/security/security.c b/security/security.c
>> index 730ac65..c57354c 100644
>> --- a/security/security.c
>> +++ b/security/security.c
>> @@ -810,6 +810,9 @@ int security_file_send_sigiotask(struct task_struct *tsk,
>>
>> int security_file_receive(struct file *file)
>> {
>> +
>> + if (unlikely(IS_PRIVATE(file->f_path.dentry->d_inode)))
>> + return 0;
>> return security_ops->file_receive(file);
>> }
>
> SELinux handles this internally; see its inode_has_perm() function.
> Doing it here would prevent any security module checking at all, even of
> the struct file, which SELinux does presently do (selinux_file_receive
> calls file_has_perm which applies the fd use check and then calls
> inode_has_perm on the inode). Unless you are saying that the
> file->f_security field is also not being set correctly.

Thanks for the suggestion. I will try to do on smack side.

Best Regards,
- Seung-Woo Kim

>
>
>

--
Seung-Woo Kim
Samsung Software R&D Center
--



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