linux-kernel - [PATCH 3/4] random: Seed pools from arch_get_slow_rng

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 for Android: free password hash cracker in your pocket

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

Date:	Tue, 15 Jul 2014 19:48:09 -0700
From:	Andy Lutomirski <luto@...capital.net>
To:	kvm@...r.kernel.org, "H. Peter Anvin" <hpa@...or.com>,
	Theodore Ts'o <tytso@....edu>, linux-kernel@...r.kernel.org,
	Kees Cook <keescook@...omium.org>, x86@...nel.org
Cc:	Daniel Borkmann <dborkman@...hat.com>,
	Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>,
	Raghavendra K T <raghavendra.kt@...ux.vnet.ibm.com>,
	Andy Lutomirski <luto@...capital.net>
Subject: [PATCH 3/4] random: Seed pools from arch_get_slow_rng_u64 at startup

This should help solve the problem of guests starting out with
predictable RNG state.

Signed-off-by: Andy Lutomirski <luto@...capital.net>
---
 drivers/char/random.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 0a7ac0a..bd88a24 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1248,7 +1248,7 @@ EXPORT_SYMBOL(get_random_bytes_arch);
  */
 static void init_std_data(struct entropy_store *r)
 {
-	int i;
+	int i, slow_rng_bits = 0;
 	ktime_t now = ktime_get_real();
 	unsigned long rv;
 
@@ -1261,6 +1261,18 @@ static void init_std_data(struct entropy_store *r)
 		mix_pool_bytes(r, &rv, sizeof(rv), NULL);
 	}
 	mix_pool_bytes(r, utsname(), sizeof(*(utsname())), NULL);
+
+	for (i = 0; i < 4; i++) {
+		u64 rv64;
+
+		if (arch_get_slow_rng_u64(&rv64)) {
+			mix_pool_bytes(r, &rv64, sizeof(rv64), NULL);
+			slow_rng_bits += 8 * sizeof(rv64);
+		}
+	}
+	if (slow_rng_bits)
+		pr_info("random: seeded %s pool with %d bits of arch slow rng data\n",
+		       r->name, slow_rng_bits);
 }
 
 /*
-- 
1.9.3

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/