sched/autogroup: Fix possible Spectre-v1 indexing for sched_prio_to_weight[]
commit 354d779307
upstream.
> 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 (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
pull/10/head
parent
f2a42c6bca
commit
bb0b090d83
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@ -7,6 +7,7 @@
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#include <linux/utsname.h>
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#include <linux/security.h>
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#include <linux/export.h>
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#include <linux/nospec.h>
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unsigned int __read_mostly sysctl_sched_autogroup_enabled = 1;
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static struct autogroup autogroup_default;
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@ -213,7 +214,7 @@ int proc_sched_autogroup_set_nice(struct task_struct *p, int nice)
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static unsigned long next = INITIAL_JIFFIES;
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struct autogroup *ag;
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unsigned long shares;
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int err;
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int err, idx;
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if (nice < MIN_NICE || nice > MAX_NICE)
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return -EINVAL;
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@ -231,7 +232,9 @@ int proc_sched_autogroup_set_nice(struct task_struct *p, int nice)
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next = HZ / 10 + jiffies;
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ag = autogroup_task_get(p);
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shares = scale_load(sched_prio_to_weight[nice + 20]);
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idx = array_index_nospec(nice + 20, 40);
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shares = scale_load(sched_prio_to_weight[idx]);
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down_write(&ag->lock);
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err = sched_group_set_shares(ag->tg, shares);
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