lkml.org 
[lkml]   [2010]   [Jun]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [patch v2] fcntl: return -EFAULT if copy_to_user fails
(2010/06/03 22:10), Nick Piggin wrote:
> On Thu, Jun 03, 2010 at 02:38:03PM +0200, Eric Dumazet wrote:
>> Le jeudi 03 juin 2010 à 21:16 +0900, Takuya Yoshikawa a écrit :
>>> (2010/06/03 20:59), Jens Axboe wrote:
>>>> On 2010-06-03 12:35, Dan Carpenter wrote:
>>>>> copy_to_user() returns the number of bytes remaining, but we want to
>>>>> return -EFAULT.
>>>>> ret = fcntl(fd, F_SETOWN_EX, NULL);
>>>>> With the original code ret would be 8 here.
>>>>>
>>>>> V2: Takuya Yoshikawa pointed out a similar issue in f_getown_ex()
>>>>
>>>> Pretty basic bug, how long has this been there?
>>>
>>> IIUC, from the beginning, when these were introduced.
>>
>> Maybe copy_to_user() was changed sometime to return a partial count
>> instead of EFAULT ?
>
> I think it's been like that since first introduced. Some functions
> do need to know in order to do partial copies.
>
>
>> I do think we should have a set of helper functions, instead of
>> spreading special EFAULT cases in one housand places...
>>
>> This is really ugly.
>>
>> static inline int sec_copy_to_user(arg1, arg2, arg3)
>> {
>> int res = copy_to_user(arg1, arg2, arg3);
>>
>> return (res> 0) ? -EFAULT : res;
>> }
>
> It would be unfortunate if it adds more confusion. I'd prefer to have
> a sufficiently different name. memcpy_to_user/memcpy_from_user
> perhaps?

Then, and memclear_user() ?

>

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2010-06-03 15:23    [W:0.110 / U:1.544 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site