lkml.org 
[lkml]   [2018]   [Jun]   [6]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH V2] xfs: fix string handling in get/set functions
From
Date


On 6/6/18 5:58 AM, Christoph Hellwig wrote:
>> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
>> index 82f7c83c1dad..596e176c19a6 100644
>> --- a/fs/xfs/xfs_ioctl.c
>> +++ b/fs/xfs/xfs_ioctl.c
>> @@ -1828,13 +1828,13 @@ xfs_ioc_getlabel(
>> /* Paranoia */
>> BUILD_BUG_ON(sizeof(sbp->sb_fname) > FSLABEL_MAX);
>>
>> + /* 1 larger than sb_fname, so this ensures a trailing NUL char */
>> + memset(label, 0, sizeof(label));
>
> I don't get the comment. In fact I don't even get why we need any
> comment here. This is a structure that gets copied to userspace,
> and we zero the whole structure, as we should do by default for
> anything that goes to userspace.

Sure, I guess we didn't really need the comment, my main point was that
we were guaranteed to have a \0 remaining at the end because we'd never copy
over it due to sb_fname's smaller size.

> Otherwise this looks fine to me.

Thanks. In retrospect we could have gone back to Arnd's original patch
but I guess the explicit memset is ... well, nice and explicit.

-Eric

\
 
 \ /
  Last update: 2018-06-06 19:46    [W:1.222 / U:0.120 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site