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| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-09-20 17:12:00 +0300 |
|---|---|---|
| committer | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-09-23 13:27:57 +0300 |
| commit | d775335e350fc07e1322960ee291dc9079ab938e (patch) | |
| tree | 9459588ff43af5215f615cf945fd2db7fbefe43a /drivers/char/random.c | |
| parent | 745558f9588551b1fef9609d165e239bce30d3e8 (diff) | |
| download | linux-d775335e350fc07e1322960ee291dc9079ab938e.tar.xz | |
random: throttle hwrng writes if no entropy is credited
If a hwrng source does not provide an entropy estimate, it currently
does not contribute at all to the CRNG. In order to help fix this, in
case add_hwgenerator_randomness() is called with the entropy parameter
set to zero, go to sleep until one reseed interval has passed.
While the hwrng thread currently only runs under conditions where this
is non-zero, this change is not harmful and prepares for future updates
to the hwrng core.
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'drivers/char/random.c')
| -rw-r--r-- | drivers/char/random.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index 16e0c5f6cf2f..520a385c7dab 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -865,9 +865,9 @@ void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy) /* * Throttle writing to once every reseed interval, unless we're not yet - * initialized. + * initialized or no entropy is credited. */ - if (!kthread_should_stop() && crng_ready()) + if (!kthread_should_stop() && (crng_ready() || !entropy)) schedule_timeout_interruptible(crng_reseed_interval()); } EXPORT_SYMBOL_GPL(add_hwgenerator_randomness); |