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vsprintf: initialize siphash key using notifier
Rather than polling every second, use the new notifier to do this at exactly the right moment. Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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@ -41,6 +41,7 @@
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#include <linux/siphash.h>
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#include <linux/compiler.h>
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#include <linux/property.h>
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#include <linux/notifier.h>
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#ifdef CONFIG_BLOCK
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#include <linux/blkdev.h>
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#endif
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@ -752,26 +753,21 @@ early_param("debug_boot_weak_hash", debug_boot_weak_hash_enable);
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static bool filled_random_ptr_key __read_mostly;
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static siphash_key_t ptr_key __read_mostly;
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static void fill_ptr_key_workfn(struct work_struct *work);
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static DECLARE_DELAYED_WORK(fill_ptr_key_work, fill_ptr_key_workfn);
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static void fill_ptr_key_workfn(struct work_struct *work)
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static int fill_ptr_key(struct notifier_block *nb, unsigned long action, void *data)
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{
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if (!rng_is_initialized()) {
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queue_delayed_work(system_unbound_wq, &fill_ptr_key_work, HZ * 2);
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return;
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}
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get_random_bytes(&ptr_key, sizeof(ptr_key));
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/* Pairs with smp_rmb() before reading ptr_key. */
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smp_wmb();
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WRITE_ONCE(filled_random_ptr_key, true);
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return NOTIFY_DONE;
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}
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static int __init vsprintf_init_hashval(void)
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{
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fill_ptr_key_workfn(NULL);
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static struct notifier_block fill_ptr_key_nb = { .notifier_call = fill_ptr_key };
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execute_with_initialized_rng(&fill_ptr_key_nb);
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return 0;
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}
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subsys_initcall(vsprintf_init_hashval)
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