[email protected] (Eric W. Biederman) writes: > Andrew Morton <[email protected]> writes: > >> On Wed, 16 Sep 2015 12:58:04 -0700 [email protected] wrote: >> >>> 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. >> >> (cc Eric) > (cc Containers) > > Interesting. Strictly speaking the current behavior is not wrong. > Searching for all threads with a given uid has nothing to do with pids > so the pid namespace not limiting them is natural. > > In practice I don't think anyone cares either way (except people with > one color or another of security hat on) so this might be a change we > can actually make. > > In general it is probably better not to share uids and gids between > containers. > > Ben do you have a use case where this actually matters? Or was this a > case of "That looks wrong..."? > > Eric
I believe we generally want this for isolation of a process, without requiring root initially (and a non-trivial uid_map, not to mention creating the extra users, requires root). There are probably other holes in using namespaces like this, but are they intended? (Cc the relevant team member at google) > >>> Signed-off-by: Ben Segall <[email protected]> >>> Cc: Oleg Nesterov <[email protected]> >>> Cc: Al Viro <[email protected]> >>> --- >>> block/ioprio.c | 6 ++++-- >>> kernel/sys.c | 4 ++-- >>> 2 files changed, 6 insertions(+), 4 deletions(-) >>> >>> diff --git a/block/ioprio.c b/block/ioprio.c >>> index 31666c9..cc7800e 100644 >>> --- a/block/ioprio.c >>> +++ b/block/ioprio.c >>> @@ -123,7 +123,8 @@ SYSCALL_DEFINE3(ioprio_set, int, which, int, who, int, >>> ioprio) >>> break; >>> >>> do_each_thread(g, p) { >>> - if (!uid_eq(task_uid(p), uid)) >>> + if (!uid_eq(task_uid(p), uid) || >>> + !task_pid_vnr(p)) >>> continue; >>> ret = set_task_ioprio(p, ioprio); >>> if (ret) >>> @@ -220,7 +221,8 @@ SYSCALL_DEFINE2(ioprio_get, int, which, int, who) >>> break; >>> >>> do_each_thread(g, p) { >>> - if (!uid_eq(task_uid(p), user->uid)) >>> + if (!uid_eq(task_uid(p), user->uid) || >>> + !task_pid_vnr(p)) >>> continue; >>> tmpio = get_task_ioprio(p); >>> if (tmpio < 0) >>> diff --git a/kernel/sys.c b/kernel/sys.c >>> index fa2f2f6..6af9212 100644 >>> --- a/kernel/sys.c >>> +++ b/kernel/sys.c >>> @@ -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; >>> -- >>> 2.6.0.rc0.131.gf624c3d >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in >>> the body of a message to [email protected] >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >>> Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
