Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751567AbdFFRsV (ORCPT ); Tue, 6 Jun 2017 13:48:21 -0400 Received: from frisell.zx2c4.com ([192.95.5.64]:38383 "EHLO frisell.zx2c4.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751542AbdFFRsU (ORCPT ); Tue, 6 Jun 2017 13:48:20 -0400 From: "Jason A. Donenfeld" To: "Theodore Ts'o" , Linux Crypto Mailing List , LKML , kernel-hardening@lists.openwall.com, Greg Kroah-Hartman , David Miller , Eric Biggers Cc: "Jason A. Donenfeld" , Herbert Xu Subject: [PATCH v4 05/13] crypto/rng: ensure that the RNG is ready before using Date: Tue, 6 Jun 2017 19:47:56 +0200 Message-Id: <20170606174804.31124-6-Jason@zx2c4.com> X-Mailer: git-send-email 2.13.0 In-Reply-To: <20170606174804.31124-1-Jason@zx2c4.com> References: <20170606174804.31124-1-Jason@zx2c4.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 899 Lines: 34 Otherwise, we might be seeding the RNG using bad randomness, which is dangerous. The one use of this function from within the kernel -- not from userspace -- is being removed (keys/big_key), so that call site isn't relevant in assessing this. Cc: Herbert Xu Signed-off-by: Jason A. Donenfeld --- crypto/rng.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/crypto/rng.c b/crypto/rng.c index f46dac5288b9..e042437e64b4 100644 --- a/crypto/rng.c +++ b/crypto/rng.c @@ -48,12 +48,14 @@ int crypto_rng_reset(struct crypto_rng *tfm, const u8 *seed, unsigned int slen) if (!buf) return -ENOMEM; - get_random_bytes(buf, slen); + err = get_random_bytes_wait(buf, slen); + if (err) + goto out; seed = buf; } err = crypto_rng_alg(tfm)->seed(tfm, seed, slen); - +out: kzfree(buf); return err; } -- 2.13.0