From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751556AbdFHM3q (ORCPT ); Thu, 8 Jun 2017 08:29:46 -0400 Received: from frisell.zx2c4.com ([192.95.5.64]:35301 "EHLO frisell.zx2c4.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751530AbdFHM3o (ORCPT ); Thu, 8 Jun 2017 08:29:44 -0400 From: "Jason A. Donenfeld" To: "Theodore Ts'o" , LKML Cc: "Jason A. Donenfeld" , David Howells , Mimi Zohar , David Safford Subject: [PATCH cleanups/resubmit 1/4] security/keys: ensure RNG is seeded before use Date: Thu, 8 Jun 2017 14:29:29 +0200 Message-Id: <20170608122932.23769-2-Jason@zx2c4.com> In-Reply-To: <20170608122932.23769-1-Jason@zx2c4.com> References: <20170608122932.23769-1-Jason@zx2c4.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Otherwise, we might use bad random numbers which, particularly in the case of IV generation, could be quite bad. It makes sense to use the synchronous API here, because we're always in process context (as the code is littered with GFP_KERNEL and the like). However, we can't change to using a blocking function in key serial allocation, because this will block booting in some configurations, so here we use the more appropriate get_random_u32, which will use RDRAND if available. Signed-off-by: Jason A. Donenfeld Cc: David Howells Cc: Mimi Zohar Cc: David Safford --- security/keys/encrypted-keys/encrypted.c | 8 +++++--- security/keys/key.c | 8 +++----- 2 files changed, 8 insertions(+), 8 deletions(-) diff --git a/security/keys/encrypted-keys/encrypted.c b/security/keys/encrypted-keys/encrypted.c index 0010955d7876..d51a28fc5cd5 100644 --- a/security/keys/encrypted-keys/encrypted.c +++ b/security/keys/encrypted-keys/encrypted.c @@ -777,10 +777,12 @@ static int encrypted_init(struct encrypted_key_payload *epayload, __ekey_init(epayload, format, master_desc, datalen); if (!hex_encoded_iv) { - get_random_bytes(epayload->iv, ivsize); + ret = get_random_bytes_wait(epayload->iv, ivsize); + if (unlikely(ret)) + return ret; - get_random_bytes(epayload->decrypted_data, - epayload->decrypted_datalen); + ret = get_random_bytes_wait(epayload->decrypted_data, + epayload->decrypted_datalen); } else ret = encrypted_key_decrypt(epayload, format, hex_encoded_iv); return ret; diff --git a/security/keys/key.c b/security/keys/key.c index 455c04d80bbb..b1db72d0ab1b 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -139,12 +139,10 @@ static inline void key_alloc_serial(struct key *key) struct rb_node *parent, **p; struct key *xkey; - /* propose a random serial number and look for a hole for it in the - * serial number tree */ + /* propose a non-negative random serial number and look for a hole for + * it in the serial number tree */ do { - get_random_bytes(&key->serial, sizeof(key->serial)); - - key->serial >>= 1; /* negative numbers are not permitted */ + key->serial = get_random_u32() >> 1; } while (key->serial < 3); spin_lock(&key_serial_lock); -- 2.13.0