lkml.org 
[lkml]   [2020]   [Jul]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH v7 4/7] fs: Introduce O_MAYEXEC flag for openat2(2)
Date
* Al Viro:

> On Thu, Jul 23, 2020 at 07:12:24PM +0200, Mickaël Salaün wrote:
>> When the O_MAYEXEC flag is passed, openat2(2) may be subject to
>> additional restrictions depending on a security policy managed by the
>> kernel through a sysctl or implemented by an LSM thanks to the
>> inode_permission hook. This new flag is ignored by open(2) and
>> openat(2) because of their unspecified flags handling. When used with
>> openat2(2), the default behavior is only to forbid to open a directory.
>
> Correct me if I'm wrong, but it looks like you are introducing a magical
> flag that would mean "let the Linux S&M take an extra special whip
> for this open()".
>
> Why is it done during open? If the caller is passing it deliberately,
> why not have an explicit request to apply given torture device to an
> already opened file? Why not sys_masochism(int fd, char *hurt_flavour),
> for that matter?

While I do not think this is appropriate language for a workplace, Al
has a point: If the auditing event can be generated on an already-open
descriptor, it would also cover scenarios like this one:

perl < /path/to/script

Where the process that opens the file does not (and cannot) know that it
will be used for execution purposes.

Thanks,
Florian

\
 
 \ /
  Last update: 2020-07-27 07:28    [W:0.123 / U:1.028 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site