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| author | Jason A. Donenfeld <Jason@zx2c4.com> | 2022-01-29 01:44:03 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-02-23 14:03:07 +0300 |
| commit | b16817a6de315b1587616e351f4ee83b416e8cb5 (patch) | |
| tree | 6047fcfb7fe716dd0ae45cba7d9236294d45275d /drivers/char | |
| parent | effdcc25058484aaf64b1557efb124c87a733045 (diff) | |
| download | linux-b16817a6de315b1587616e351f4ee83b416e8cb5.tar.xz | |
random: wake up /dev/random writers after zap
[ Upstream commit 042e293e16e3aa9794ce60c29f5b7b0c8170f933 ]
When account() is called, and the amount of entropy dips below
random_write_wakeup_bits, we wake up the random writers, so that they
can write some more in. However, the RNDZAPENTCNT/RNDCLEARPOOL ioctl
sets the entropy count to zero -- a potential reduction just like
account() -- but does not unblock writers. This commit adds the missing
logic to that ioctl to unblock waiting writers.
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/random.c | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index a27ae3999ff3..ebe86de9d0ac 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -1963,7 +1963,10 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg) */ if (!capable(CAP_SYS_ADMIN)) return -EPERM; - input_pool.entropy_count = 0; + if (xchg(&input_pool.entropy_count, 0) && random_write_wakeup_bits) { + wake_up_interruptible(&random_write_wait); + kill_fasync(&fasync, SIGIO, POLL_OUT); + } return 0; case RNDRESEEDCRNG: if (!capable(CAP_SYS_ADMIN)) |