Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757542Ab0KLM77 (ORCPT ); Fri, 12 Nov 2010 07:59:59 -0500 Received: from igw2.watson.ibm.com ([129.34.20.6]:55483 "EHLO igw2.watson.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757104Ab0KLM76 convert rfc822-to-8bit (ORCPT ); Fri, 12 Nov 2010 07:59:58 -0500 Subject: Re: [PATCH v1.3 3/4] keys: add new trusted key-type From: David Safford To: David Howells Cc: Mimi Zohar , linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, keyrings@linux-nfs.org, linux-crypto@vger.kernel.org, Jason Gunthorpe , James Morris , Rajiv Andrade , Mimi Zohar In-Reply-To: <8100.1289512670@redhat.com> References: <1289404309-15955-4-git-send-email-zohar@linux.vnet.ibm.com> <1289404309-15955-1-git-send-email-zohar@linux.vnet.ibm.com> <8100.1289512670@redhat.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8BIT Date: Fri, 12 Nov 2010 07:58:11 -0500 Message-ID: <1289566691.4341.21.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.32.0 (2.32.0-2.fc14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1571 Lines: 39 On Thu, 2010-11-11 at 21:57 +0000, David Howells wrote: > Mimi Zohar wrote: Thanks for the helpful comments - much appreciated. Willdo on all of them - just one question on the last comment: > > +/* > > + * Have the TPM seal(encrypt) the trusted key, possibly based on > > + * Platform Configuration Registers (PCRs). AUTH1 for sealing key. > > + */ > > +static int tpm_seal(struct tpm_buf *tb, uint16_t keytype, > > + uint32_t keyhandle, unsigned char *keyauth, > > + unsigned char *data, uint32_t datalen, > > + unsigned char *blob, uint32_t * bloblen, > > + unsigned char *blobauth, > > + unsigned char *pcrinfo, uint32_t pcrinfosize) > > +{ > > + struct osapsess sess; > > + unsigned char encauth[TPM_HASH_SIZE]; > > + unsigned char pubauth[TPM_HASH_SIZE]; > > + unsigned char xorwork[TPM_HASH_SIZE * 2]; > > + unsigned char xorhash[TPM_HASH_SIZE]; > > + unsigned char nonceodd[TPM_NONCE_SIZE]; > > That's quite a lot of stack space, and you're calling other functions that > also allocate chunks of stack space. checkstack showed that the max stack usage was for tpm_seal, at 530 bytes. (The rest were 300 or less.) I can certainly throw the hashes and nonce (120 bytes) into a dynamically allocated struct, if you think it is worth the extra code... thanks dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/