Messages in this thread Patch in this message | | | Date | Fri, 20 Apr 2018 15:14:14 +0200 | From | Peter Zijlstra <> | Subject | [PATCH 7/7] sched,autogroup: Fix possible Spectre-v1 for sched_prio_to_weight |
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> kernel/sched/autogroup.c:230 proc_sched_autogroup_set_nice() warn: potential spectre issue 'sched_prio_to_weight'
Userspace controls @nice, sanitize the array index.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> --- kernel/sched/autogroup.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/kernel/sched/autogroup.c +++ b/kernel/sched/autogroup.c @@ -209,7 +209,7 @@ int proc_sched_autogroup_set_nice(struct static unsigned long next = INITIAL_JIFFIES; struct autogroup *ag; unsigned long shares; - int err; + int err, idx; if (nice < MIN_NICE || nice > MAX_NICE) return -EINVAL; @@ -227,7 +227,9 @@ int proc_sched_autogroup_set_nice(struct next = HZ / 10 + jiffies; ag = autogroup_task_get(p); - shares = scale_load(sched_prio_to_weight[nice + 20]); + + idx = array_index_nospec(nice + 20, 40); + shares = scale_load(sched_prio_to_weight[idx]); down_write(&ag->lock); err = sched_group_set_shares(ag->tg, shares);
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