From b5624be6df95fd26d19051af5d02001bbe8f2dd8 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Sun, 1 May 2022 16:37:39 +0200 Subject: [PATCH] seedrng: reduce MAX_SEED_LEN from 512 to 256 As proposed by Jason. getrandom() is more likely to block on reads larger than this. Signed-off-by: Denys Vlasenko --- util-linux/seedrng.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/util-linux/seedrng.c b/util-linux/seedrng.c index 2965f3d47..04e52a996 100644 --- a/util-linux/seedrng.c +++ b/util-linux/seedrng.c @@ -56,7 +56,11 @@ enum { MIN_SEED_LEN = SHA256_OUTSIZE, - MAX_SEED_LEN = 512 + /* kernels < 5.18 could return short reads from getrandom() + * if signal is pending and length is > 256. + * Let's limit our reads to 256 bytes. + */ + MAX_SEED_LEN = 256, }; static size_t determine_optimal_seed_len(void)