Commit 8639b461 authored by Ben Segall's avatar Ben Segall Committed by Linus Torvalds

pidns: fix set/getpriority and ioprio_set/get in PRIO_USER mode

setpriority(PRIO_USER, 0, x) will change the priority of tasks outside of
the current pid namespace.  This is in contrast to both the other modes of
setpriority and the example of kill(-1).  Fix this.  getpriority and
ioprio have the same failure mode, fix them too.

Eric said:

: After some more thinking about it this patch sounds justifiable.
: My goal with namespaces is not to build perfect isolation mechanisms
: as that can get into ill defined territory, but to build well defined
: mechanisms.  And to handle the corner cases so you can use only
: a single namespace with well defined results.
: In this case you have found the two interfaces I am aware of that
: identify processes by uid instead of by pid.  Which quite frankly is
: weird.  Unfortunately the weird unexpected cases are hard to handle
: in the usual way.
: I was hoping for a little more information.  Changes like this one we
: have to be careful of because someone might be depending on the current
: behavior.  I don't think they are and I do think this make sense as part
: of the pid namespace.
Signed-off-by: default avatarBen Segall <>
Cc: Oleg Nesterov <>
Cc: Al Viro <>
Cc: Ambrose Feinstein <>
Acked-by: default avatar"Eric W. Biederman" <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent de90a6bc
......@@ -123,7 +123,8 @@ SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, ioprio)
do_each_thread(g, p) {
if (!uid_eq(task_uid(p), uid))
if (!uid_eq(task_uid(p), uid) ||
ret = set_task_ioprio(p, ioprio);
if (ret)
......@@ -220,7 +221,8 @@ SYSCALL_DEFINE2(ioprio_get, int, which, int, who)
do_each_thread(g, p) {
if (!uid_eq(task_uid(p), user->uid))
if (!uid_eq(task_uid(p), user->uid) ||
tmpio = get_task_ioprio(p);
if (tmpio < 0)
......@@ -222,7 +222,7 @@ SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval)
goto out_unlock; /* No processes for this user */
do_each_thread(g, p) {
if (uid_eq(task_uid(p), uid))
if (uid_eq(task_uid(p), uid) && task_pid_vnr(p))
error = set_one_prio(p, niceval, error);
} while_each_thread(g, p);
if (!uid_eq(uid, cred->uid))
......@@ -290,7 +290,7 @@ SYSCALL_DEFINE2(getpriority, int, which, int, who)
goto out_unlock; /* No processes for this user */
do_each_thread(g, p) {
if (uid_eq(task_uid(p), uid)) {
if (uid_eq(task_uid(p), uid) && task_pid_vnr(p)) {
niceval = nice_to_rlimit(task_nice(p));
if (niceval > retval)
retval = niceval;
Markdown is supported
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