Commit 97829955 authored by Serge E. Hallyn's avatar Serge E. Hallyn Committed by Linus Torvalds
Browse files

oom_kill: remove uid==0 checks



Root processes are considered more important when out of memory and killing
proceses.  The check for CAP_SYS_ADMIN was augmented with a check for
uid==0 or euid==0.

There are several possible ways to look at this:

	1. uid comparisons are unnecessary, trust CAP_SYS_ADMIN
	   alone.  However CAP_SYS_RESOURCE is the one that really
	   means "give me extra resources" so allow for that as
	   well.
	2. Any privileged code should be protected, but uid is not
	   an indication of privilege.  So we should check whether
	   any capabilities are raised.
	3. uid==0 makes processes on the host as well as in containers
	   more important, so we should keep the existing checks.
	4. uid==0 makes processes only on the host more important,
	   even without any capabilities.  So we should be keeping
	   the (uid==0||euid==0) check but only when
	   userns==&init_user_ns.

I'm following number 1 here.
Signed-off-by: default avatarSerge Hallyn <serue@us.ibm.com>
Cc: Andrew Morgan <morgan@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3b7391de
......@@ -125,7 +125,7 @@ unsigned long badness(struct task_struct *p, unsigned long uptime)
* Superuser processes are usually more important, so we make it
* less likely that we kill those.
*/
if (__capable(p, CAP_SYS_ADMIN) || p->uid == 0 || p->euid == 0)
if (__capable(p, CAP_SYS_ADMIN) || __capable(p, CAP_SYS_RESOURCE))
points /= 4;
/*
......
Supports Markdown
0% or .
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment