From patchwork Wed Jun 7 23:25:58 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Jason A. Donenfeld" X-Patchwork-Id: 9773305 X-Patchwork-Delegate: herbert@gondor.apana.org.au Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 5CEDB60234 for ; Wed, 7 Jun 2017 23:28:44 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 52105283AD for ; Wed, 7 Jun 2017 23:28:44 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 45DA62848D; Wed, 7 Jun 2017 23:28:44 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C49C9283AD for ; Wed, 7 Jun 2017 23:28:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751891AbdFGX2b (ORCPT ); Wed, 7 Jun 2017 19:28:31 -0400 Received: from frisell.zx2c4.com ([192.95.5.64]:33481 "EHLO frisell.zx2c4.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752982AbdFGX0c (ORCPT ); Wed, 7 Jun 2017 19:26:32 -0400 Received: by frisell.zx2c4.com (ZX2C4 Mail Server) with ESMTP id 86d875ef; Wed, 7 Jun 2017 23:25:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=zx2c4.com; h=from:to:cc :subject:date:message-id:in-reply-to:references; s=mail; bh=CEl3 SZwHmEChf0jQgaJFq+nROLQ=; b=syg1tcRHXFdt3DiDtRutPMT65eyqLspsdFHo +wn8ac0yMjAl/9U4GoU3TK0bAUxAySIN93oo9/AZjSpQl3OfCmzaVBFuLBhMVs9b MfmfXxCoPraJm1eyO/amkbhWfHgNoCzZGsoSviJqAamTjwRu5szpxsmDHb3qmllI xeLNEWNNExdgJEu5uE48iewnsi2kBAilis58a9Be9U9Eo/NI7YCqeEnxvSBx/BC3 NGl//MXqVZTTOnw/o/S7IYjOyYvWD7Kxs881NjX8g+jbCt/LL0pnF4iqCkOrQAqy gFCy6EXFRTeFrpaRy9wPv2zwU3Fv+We0u0/BehslDNvFaRWDLw== Received: by frisell.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id fffabd17 (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256:NO); Wed, 7 Jun 2017 23:25:50 +0000 (UTC) From: "Jason A. Donenfeld" To: Theodore Ts'o , Linux Crypto Mailing List , LKML , kernel-hardening@lists.openwall.com, Greg Kroah-Hartman , Eric Biggers , Linus Torvalds , David Miller Cc: "Jason A. Donenfeld" , David Howells , Mimi Zohar , David Safford Subject: [PATCH v5 04/13] security/keys: ensure RNG is seeded before use Date: Thu, 8 Jun 2017 01:25:58 +0200 Message-Id: <20170607232607.26870-5-Jason@zx2c4.com> In-Reply-To: <20170607232607.26870-1-Jason@zx2c4.com> References: <20170607232607.26870-1-Jason@zx2c4.com> Sender: linux-crypto-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 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 | 16 ++++++++-------- 2 files changed, 13 insertions(+), 11 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..b72078e532f2 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -134,17 +134,15 @@ void key_user_put(struct key_user *user) * Allocate a serial number for a key. These are assigned randomly to avoid * security issues through covert channel problems. */ -static inline void key_alloc_serial(struct key *key) +static inline int 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); @@ -170,7 +168,7 @@ static inline void key_alloc_serial(struct key *key) rb_insert_color(&key->serial_node, &key_serial_tree); spin_unlock(&key_serial_lock); - return; + return 0; /* we found a key with the proposed serial number - walk the tree from * that point looking for the next unused serial number */ @@ -314,7 +312,9 @@ struct key *key_alloc(struct key_type *type, const char *desc, /* publish the key by giving it a serial number */ atomic_inc(&user->nkeys); - key_alloc_serial(key); + ret = key_alloc_serial(key); + if (ret < 0) + goto security_error; error: return key;