[Buildroot] [git commit branch/2022.02.x] package/urandom-scripts: do not seed if initial seed doesn't exist

[Peter Korsgaard]

commit: https://git.buildroot.net/buildroot/commit/?id=8a2eb6ec69b6c0292b0a9c1bb487feed55d2a7f1
branch: https://git.buildroot.net/buildroot/commit/?id=refs/heads/2022.02.x

By returning a failure in the event that the initial seed doesn't exist,
we'd then skip creating a new seed, which means we'd never in fact have
an initial seed, and this script is therefore useless. Fix this by
checking for the existence of the seed file first, and just returning 0
if it's not there.

Reported-by: Nicolas Cavallari <Nicolas.Cavallari at green-communications.fr>
Reported-by: Eugen Hristev <Eugen.Hristev at microchip.com>
Signed-off-by: Jason A. Donenfeld <Jason at zx2c4.com>
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
(cherry picked from commit e65e9acb201ba2cf3f1b0b209b45d557577d8044)
Signed-off-by: Peter Korsgaard <peter at korsgaard.com>
---
 package/urandom-scripts/S20urandom | 1 +
 1 file changed, 1 insertion(+)

diff --git a/package/urandom-scripts/S20urandom b/package/urandom-scripts/S20urandom
index c6b2ebd48f..6c6aea9eee 100644
--- a/package/urandom-scripts/S20urandom
+++ b/package/urandom-scripts/S20urandom
@@ -18,6 +18,7 @@ else
 fi
 
 init_rng() {
+	[ -f "$URANDOM_SEED" ] || return 0
 	printf 'Initializing random number generator: '
 	dd if="$URANDOM_SEED" bs="$pool_size" of=/dev/urandom count=1 2> /dev/null
 	status=$?