linux-kernel - [PATCH 4.19 180/234] random: account for arch randomness in bits

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20220623164348.144426488@linuxfoundation.org>
Date:   Thu, 23 Jun 2022 18:44:07 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, "Jason A. Donenfeld" <Jason@...c4.com>
Subject: [PATCH 4.19 180/234] random: account for arch randomness in bits

From: "Jason A. Donenfeld" <Jason@...c4.com>

commit 77fc95f8c0dc9e1f8e620ec14d2fb65028fb7adc upstream.

Rather than accounting in bytes and multiplying (shifting), we can just
account in bits and avoid the shift. The main motivation for this is
there are other patches in flux that expand this code a bit, and
avoiding the duplication of "* 8" everywhere makes things a bit clearer.

Cc: stable@...r.kernel.org
Fixes: 12e45a2a6308 ("random: credit architectural init the exact amount")
Signed-off-by: Jason A. Donenfeld <Jason@...c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 drivers/char/random.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -809,7 +809,7 @@ early_param("random.trust_bootloader", p
 int __init random_init(const char *command_line)
 {
 	ktime_t now = ktime_get_real();
-	unsigned int i, arch_bytes;
+	unsigned int i, arch_bits;
 	unsigned long entropy;
 
 #if defined(LATENT_ENTROPY_PLUGIN)
@@ -817,12 +817,12 @@ int __init random_init(const char *comma
 	_mix_pool_bytes(compiletime_seed, sizeof(compiletime_seed));
 #endif
 
-	for (i = 0, arch_bytes = BLAKE2S_BLOCK_SIZE;
+	for (i = 0, arch_bits = BLAKE2S_BLOCK_SIZE * 8;
 	     i < BLAKE2S_BLOCK_SIZE; i += sizeof(entropy)) {
 		if (!arch_get_random_seed_long_early(&entropy) &&
 		    !arch_get_random_long_early(&entropy)) {
 			entropy = random_get_entropy();
-			arch_bytes -= sizeof(entropy);
+			arch_bits -= sizeof(entropy) * 8;
 		}
 		_mix_pool_bytes(&entropy, sizeof(entropy));
 	}
@@ -834,7 +834,7 @@ int __init random_init(const char *comma
 	if (crng_ready())
 		crng_reseed();
 	else if (trust_cpu)
-		_credit_init_bits(arch_bytes * 8);
+		_credit_init_bits(arch_bits);
 
 	return 0;
 }