From 24d408b9f8f057a471a7970c2220fc89a6ca522c Mon Sep 17 00:00:00 2001 From: "Jason A. Donenfeld" Date: Tue, 30 Aug 2022 18:28:01 +0800 Subject: [PATCH] random: credit architectural init the exact amount stable inclusion from stable-v5.10.119 commit 04d61b96bd8a97755d416fbbe07b4ba8bffba564 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5L6BB Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=04d61b96bd8a97755d416fbbe07b4ba8bffba564 -------------------------------- commit 12e45a2a6308105469968951e6d563e8f4fea187 upstream. RDRAND and RDSEED can fail sometimes, which is fine. We currently initialize the RNG with 512 bits of RDRAND/RDSEED. We only need 256 bits of those to succeed in order to initialize the RNG. Instead of the current "all or nothing" approach, actually credit these contributions the amount that is actually contributed. Reviewed-by: Dominik Brodowski Signed-off-by: Jason A. Donenfeld Signed-off-by: Greg Kroah-Hartman Signed-off-by: Zheng Zengkai Acked-by: Xie XiuQi --- drivers/char/random.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/char/random.c b/drivers/char/random.c index 2960ce4c9231..cd63bc7c5e9b 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -896,9 +896,8 @@ early_param("random.trust_bootloader", parse_trust_bootloader); */ int __init random_init(const char *command_line) { - size_t i; ktime_t now = ktime_get_real(); - bool arch_init = true; + unsigned int i, arch_bytes; unsigned long rv; #if defined(LATENT_ENTROPY_PLUGIN) @@ -906,11 +905,12 @@ int __init random_init(const char *command_line) _mix_pool_bytes(compiletime_seed, sizeof(compiletime_seed)); #endif - for (i = 0; i < BLAKE2S_BLOCK_SIZE; i += sizeof(rv)) { + for (i = 0, arch_bytes = BLAKE2S_BLOCK_SIZE; + i < BLAKE2S_BLOCK_SIZE; i += sizeof(rv)) { if (!arch_get_random_seed_long_early(&rv) && !arch_get_random_long_early(&rv)) { rv = random_get_entropy(); - arch_init = false; + arch_bytes -= sizeof(rv); } _mix_pool_bytes(&rv, sizeof(rv)); } @@ -921,8 +921,8 @@ int __init random_init(const char *command_line) if (crng_ready()) crng_reseed(); - else if (arch_init && trust_cpu) - credit_init_bits(BLAKE2S_BLOCK_SIZE * 8); + else if (trust_cpu) + credit_init_bits(arch_bytes * 8); return 0; } -- GitLab