From patchwork Wed Nov 24 16:43:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jianglei Nie X-Patchwork-Id: 12637169 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 91EF7C433F5 for ; Wed, 24 Nov 2021 17:02:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349391AbhKXRFT (ORCPT ); Wed, 24 Nov 2021 12:05:19 -0500 Received: from mail-m972.mail.163.com ([123.126.97.2]:47782 "EHLO mail-m972.mail.163.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242707AbhKXRFT (ORCPT ); Wed, 24 Nov 2021 12:05:19 -0500 X-Greylist: delayed 924 seconds by postgrey-1.27 at vger.kernel.org; Wed, 24 Nov 2021 12:05:17 EST DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:Subject:Date:Message-Id:MIME-Version; bh=8ERBp /cCG6WzioJCfEWJSK1orI4R+L3An4qXLiZdnB0=; b=OXoqhebDEZzeJ7/tZsJ8J SmHIkZsNHWXXKsahcfmp5T5PaR4vFOn43TKWCwZtcdsvse2Y3iS9n2yfkEkCP2Ci UjVtEpPgC5S6Qv0Tiq1HAYq9yLfeKz9fnQYKqFL7FONJ8brCFR5+TGnmQhNDGfVy crGX80h2iLKCQeg3+CzZFY= Received: from localhost.localdomain (unknown [218.106.182.227]) by smtp2 (Coremail) with SMTP id GtxpCgBHHNXNa55h7hmJKQ--.39097S4; Thu, 25 Nov 2021 00:44:01 +0800 (CST) From: Jianglei Nie To: jejb@linux.ibm.com, jarkko@kernel.org, zohar@linux.ibm.com, dhowells@redhat.com, jmorris@namei.org, serge@hallyn.com Cc: linux-integrity@vger.kernel.org, keyrings@vger.kernel.org, linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, Jianglei Nie Subject: [PATCH] security:trusted_tpm2: Fix memory leak in tpm2_key_encode() Date: Thu, 25 Nov 2021 00:43:54 +0800 Message-Id: <20211124164354.20448-1-niejianglei2021@163.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-CM-TRANSID: GtxpCgBHHNXNa55h7hmJKQ--.39097S4 X-Coremail-Antispam: 1Uf129KBjvJXoWxJw18Ww1kWF15Gry3XrWrZrb_yoW5XryUpF ZxKF17ZrWagry7Ary7Ja1Svr1fCay5Gr47GwsrW39rGasxJFsxtFy7ArWYgrnrAFWfKw15 ZF4qvFWUWrWDtrUanT9S1TB71UUUUUUqnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07bY2-5UUUUU= X-Originating-IP: [218.106.182.227] X-CM-SenderInfo: xqlhyxxdqjzvrlsqjii6rwjhhfrp/1tbi6xFVjFXlyRVF+AAAsy Precedence: bulk List-ID: X-Mailing-List: linux-integrity@vger.kernel.org From: Jianglei Nie Line 36 (#1) allocates a memory chunk for scratch by kmalloc(), but it is never freed through the function, which will lead to a memory leak. We should kfree() scratch before the function returns (#2, #3 and #4). 31 static int tpm2_key_encode(struct trusted_key_payload *payload, 32 struct trusted_key_options *options, 33 u8 *src, u32 len) 34 { 36 u8 *scratch = kmalloc(SCRATCH_SIZE, GFP_KERNEL); // #1: kmalloc space 37 u8 *work = scratch, *work1; 50 if (!scratch) 51 return -ENOMEM; 56 if (options->blobauth_len == 0) { 60 if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) 61 return PTR_ERR(w); // #2: missing kfree 63 } 71 if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE, 72 "BUG: scratch buffer is too small")) 73 return -EINVAL; // #3: missing kfree // #4: missing kfree: scratch is never used afterwards. 82 if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed")) 83 return PTR_ERR(work1); 85 return work1 - payload->blob; 86 } Signed-off-by: Jianglei Nie --- security/keys/trusted-keys/trusted_tpm2.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/security/keys/trusted-keys/trusted_tpm2.c b/security/keys/trusted-keys/trusted_tpm2.c index 0165da386289..99bb8b2409ac 100644 --- a/security/keys/trusted-keys/trusted_tpm2.c +++ b/security/keys/trusted-keys/trusted_tpm2.c @@ -57,8 +57,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, unsigned char bool[3], *w = bool; /* tag 0 is emptyAuth */ w = asn1_encode_boolean(w, w + sizeof(bool), true); - if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) + if (WARN(IS_ERR(w), "BUG: Boolean failed to encode")) { + kfree(scratch); return PTR_ERR(w); + } work = asn1_encode_tag(work, end_work, 0, bool, w - bool); } @@ -69,8 +71,10 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, * trigger, so if it does there's something nefarious going on */ if (WARN(work - scratch + pub_len + priv_len + 14 > SCRATCH_SIZE, - "BUG: scratch buffer is too small")) + "BUG: scratch buffer is too small")){ + kfree(scratch); return -EINVAL; + } work = asn1_encode_integer(work, end_work, options->keyhandle); work = asn1_encode_octet_string(work, end_work, pub, pub_len); @@ -79,6 +83,7 @@ static int tpm2_key_encode(struct trusted_key_payload *payload, work1 = payload->blob; work1 = asn1_encode_sequence(work1, work1 + sizeof(payload->blob), scratch, work - scratch); + kfree(scratch); if (WARN(IS_ERR(work1), "BUG: ASN.1 encoder failed")) return PTR_ERR(work1);