On Wed, Feb 28, 2018 at 9:18 AM, Stephen Smalley <sds@xxxxxxxxxxxxx> wrote:
> On 02/28/2018 08:53 AM, Stephen Smalley wrote:
>> On 02/28/2018 04:53 AM, Dominick Grift wrote:
>>> On Wed, Feb 28, 2018 at 10:27:08AM +0100, Dominick Grift wrote:
>>>> Since Linux 4.16 (to atleast RC2) user space started to excessively trigger cap_sys_module
>>>>
>>>> Here is one example of such and event:
>>>>
>>>> type=SYSCALL msg=audit(02/27/2018 08:06:40.017:74) : arch=x86_64 syscall=ioctl success=no exit=ENOTTY(Inappropriate ioctl for device) a0=0x2 a1=TCGETS a2=0x7fff2d89f8f0 a3=0x55ba203a9010 items=0 ppid=1 pid=423 auid=unset uid=root gid=root euid=root suid=root fsuid=root egid=root sgid=root fsgid=root tty=(none) ses=unset comm=systemd-user-se exe=/usr/lib/systemd/systemd-user-sessions subj=sys.id:sys.role:user_sessions.subj:s0 key=(null)
>>>> type=AVC msg=audit(02/27/2018 08:06:40.017:74) : avc: denied { sys_module } for pid=423 comm=systemd-user-se capability=sys_module scontext=sys.id:sys.role:user_sessions.subj:s0 tcontext=sys.id:sys.role:user_sessions.subj:s0 tclass=capability permissive=1
>>>> type=AVC msg=audit(02/27/2018 08:06:40.017:74) : avc: denied { module_request } for pid=423 comm=systemd-user-se kmod=6E65746465762D80E72A05257F scontext=sys.id:sys.role:user_sessions.subj:s0 tcontext=sys.id:sys.role:sys.isid:s0 tclass=system permissive=1
>>>>
>>>> Any idea what causes this and how to fix it?
>>>
>>> For reference: https://github.com/fedora-selinux/selinux-policy/commit/2c13be1fb543c51935785e7a43b798a9f35f5aa0#comments
>>
>> Looks like this might be caused by:
>>
>> commit 44c02a2c3dc55835e9f0d8ef73966406cd805001
>> Author: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
>> Date: Thu Oct 5 12:59:44 2017 -0400
>>
>> dev_ioctl(): move copyin/copyout to callers
>>
>> Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
>>
>>
>> It moves the dev_load() call out of the switch statement, which was only
>> conditionally called in the default case if the cmd had certain values,
>> and unconditionally calls it. So we trigger module load denials on
>> simple TCGETS (isatty) probes on a socket. We need it moved back.
>
> (expanded cc list since this affects more than just SELinux)
Just in case any of you on the To/CC line missed the patch:
* https://marc.info/?l=linux-netdev&m=152037526927844&w=2
--
paul moore
www.paul-moore.com
