From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e23smtp03.au.ibm.com ([202.81.31.145]:32848 "EHLO e23smtp03.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759339AbcAUNTL (ORCPT ); Thu, 21 Jan 2016 08:19:11 -0500 Received: from localhost by e23smtp03.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Thu, 21 Jan 2016 23:19:09 +1000 Message-ID: <1453382292.9549.136.camel@linux.vnet.ibm.com> Subject: Re: [RFC PATCH v2 03/11] ima: provide buffer hash calculation function From: Mimi Zohar To: Dmitry Kasatkin Cc: linux-security-module , Dmitry Kasatkin , "Luis R. Rodriguez" , kexec@lists.infradead.org, linux-modules@vger.kernel.org, fsdevel@vger.kernel.org, David Howells , David Woodhouse , Kees Cook , Dmitry Torokhov Date: Thu, 21 Jan 2016 08:18:12 -0500 In-Reply-To: References: <1453129886-20192-1-git-send-email-zohar@linux.vnet.ibm.com> <1453129886-20192-4-git-send-email-zohar@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" Mime-Version: 1.0 Sender: owner-linux-modules@vger.kernel.org List-ID: On Tue, 2016-01-19 at 21:26 +0200, Dmitry Kasatkin wrote: > On Mon, Jan 18, 2016 at 5:11 PM, Mimi Zohar wrote: > > From: Dmitry Kasatkin > > > > This patch provides convenient buffer hash calculation function. > > > > Changelog: > > - rewrite to support loff_t sized buffers - Mimi > > (based on Fenguang Wu's testing) > > > > Signed-off-by: Dmitry Kasatkin > > Signed-off-by: Mimi Zohar > > --- > > security/integrity/ima/ima.h | 2 ++ > > security/integrity/ima/ima_crypto.c | 47 +++++++++++++++++++++++++++++++++++++ > > 2 files changed, 49 insertions(+) > > > > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h > > index fb8da36..de53631 100644 > > --- a/security/integrity/ima/ima.h > > +++ b/security/integrity/ima/ima.h > > @@ -107,6 +107,8 @@ int ima_add_template_entry(struct ima_template_entry *entry, int violation, > > const char *op, struct inode *inode, > > const unsigned char *filename); > > int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash); > > +int ima_calc_buffer_hash(const void *buf, loff_t len, > > + struct ima_digest_data *hash); > > int ima_calc_field_array_hash(struct ima_field_data *field_data, > > struct ima_template_desc *desc, int num_fields, > > struct ima_digest_data *hash); > > diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c > > index fb30ce4..8d86281 100644 > > --- a/security/integrity/ima/ima_crypto.c > > +++ b/security/integrity/ima/ima_crypto.c > > @@ -519,6 +519,53 @@ int ima_calc_field_array_hash(struct ima_field_data *field_data, > > return rc; > > } > > > > +static int calc_buffer_shash_tfm(const void *buf, loff_t size, > > + struct ima_digest_data *hash, > > + struct crypto_shash *tfm) > > +{ > > + SHASH_DESC_ON_STACK(shash, tfm); > > + unsigned int len; > > + loff_t offset = 0; > > + int rc; > > + > > + shash->tfm = tfm; > > + shash->flags = 0; > > + > > + hash->length = crypto_shash_digestsize(tfm); > > + > > + rc = crypto_shash_init(shash); > > + if (rc != 0) > > + return rc; > > + > > + len = size < PAGE_SIZE ? size : PAGE_SIZE; > > + while (offset < size) { > > + rc = crypto_shash_update(shash, buf + offset, len); > > + if (rc) > > + break; > > + offset += len; > > + } > > + > > Hello Mimi, > > May be this was my earlier patch, but it seems to have a problem of > accessing beyond end of buffer using the same len. > When buffer always padded by zeros it is not a problem, but it is a bug. > > This seems to be better version. > > while (size) { > len = size < PAGE_SIZE ? size : PAGE_SIZE; > rc = crypto_shash_update(shash, buf, len); > if (rc) > break; > buf += len; > size -= len; > } > > Please change my sign-of to: dmitry.kasatkin@huawei.com Good catch! I think I unfortunately introduce this bug. Thank you for the review! Mimi