From: "Jason A. Donenfeld" Jason@zx2c4.com
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=...
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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 linux@dominikbrodowski.net Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Acked-by: Xie XiuQi xiexiuqi@huawei.com --- 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; }