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authorJason A. Donenfeld <Jason@zx2c4.com>2022-01-28 23:44:03 +0100
committerJason A. Donenfeld <Jason@zx2c4.com>2022-02-04 19:22:32 +0100
commit042e293e16e3aa9794ce60c29f5b7b0c8170f933 (patch)
treeb0f1c07c6222f4aa408dfa7aff26fbefb0bdc2db /drivers
parentc321e907aa4803d562d6e70ebed9444ad082f953 (diff)
random: wake up /dev/random writers after zap
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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/char/random.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index 3e133d9583a0..c336c78820cd 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1856,7 +1856,10 @@ 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))