Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752300AbdFHNtp (ORCPT ); Thu, 8 Jun 2017 09:49:45 -0400 Received: from mx1.redhat.com ([209.132.183.28]:44772 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751633AbdFHNtm (ORCPT ); Thu, 8 Jun 2017 09:49:42 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com D52367EBA1 Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx03.extmail.prod.ext.phx2.redhat.com; spf=pass smtp.mailfrom=dhowells@redhat.com DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.redhat.com D52367EBA1 Organization: Red Hat UK Ltd. Registered Address: Red Hat UK Ltd, Amberley Place, 107-111 Peascod Street, Windsor, Berkshire, SI4 1TE, United Kingdom. Registered in England and Wales under Company Registration No. 3798903 Subject: [PATCH 18/23] KEYS: DH: forbid using digest_null as the KDF hash From: David Howells To: jmorris@namei.org Cc: Eric Biggers , Stephan Mueller , linux-kernel@vger.kernel.org, dhowells@redhat.com, linux-security-module@vger.kernel.org, keyrings@vger.kernel.org Date: Thu, 08 Jun 2017 14:49:34 +0100 Message-ID: <149692977475.11452.14202503501716155138.stgit@warthog.procyon.org.uk> In-Reply-To: <149692963884.11452.7673998701432248814.stgit@warthog.procyon.org.uk> References: <149692963884.11452.7673998701432248814.stgit@warthog.procyon.org.uk> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 08 Jun 2017 13:49:37 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1447 Lines: 53 From: Eric Biggers Requesting "digest_null" in the keyctl_kdf_params caused an infinite loop in kdf_ctr() because the "null" hash has a digest size of 0. Fix it by rejecting hash algorithms with a digest size of 0. Signed-off-by: Eric Biggers Signed-off-by: David Howells Acked-by: Stephan Mueller --- security/keys/dh.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/security/keys/dh.c b/security/keys/dh.c index e603bd912e4c..8abc70ebe22d 100644 --- a/security/keys/dh.c +++ b/security/keys/dh.c @@ -89,6 +89,7 @@ static int kdf_alloc(struct kdf_sdesc **sdesc_ret, char *hashname) struct crypto_shash *tfm; struct kdf_sdesc *sdesc; int size; + int err; /* allocate synchronous hash */ tfm = crypto_alloc_shash(hashname, 0, 0); @@ -97,16 +98,25 @@ static int kdf_alloc(struct kdf_sdesc **sdesc_ret, char *hashname) return PTR_ERR(tfm); } + err = -EINVAL; + if (crypto_shash_digestsize(tfm) == 0) + goto out_free_tfm; + + err = -ENOMEM; size = sizeof(struct shash_desc) + crypto_shash_descsize(tfm); sdesc = kmalloc(size, GFP_KERNEL); if (!sdesc) - return -ENOMEM; + goto out_free_tfm; sdesc->shash.tfm = tfm; sdesc->shash.flags = 0x0; *sdesc_ret = sdesc; return 0; + +out_free_tfm: + crypto_free_shash(tfm); + return err; } static void kdf_dealloc(struct kdf_sdesc *sdesc)