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[209.132.180.67]) by mx.google.com with ESMTP id 92si21044384plf.299.2019.05.21.00.12.25; Tue, 21 May 2019 00:12:40 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726419AbfEUHLV (ORCPT + 99 others); Tue, 21 May 2019 03:11:21 -0400 Received: from lhrrgout.huawei.com ([185.176.76.210]:32958 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725790AbfEUHLV (ORCPT ); Tue, 21 May 2019 03:11:21 -0400 Received: from LHREML714-CAH.china.huawei.com (unknown [172.18.7.107]) by Forcepoint Email with ESMTP id 9BE044E299856D3935D4; Tue, 21 May 2019 08:11:19 +0100 (IST) Received: from [10.220.96.108] (10.220.96.108) by smtpsuk.huawei.com (10.201.108.37) with Microsoft SMTP Server (TLS) id 14.3.408.0; Tue, 21 May 2019 08:11:18 +0100 Subject: Re: [PATCH v6 2/3] add a new ima template field buf To: Prakhar Srivastava , , , CC: , , References: <20190521000645.16227-1-prsriva02@gmail.com> <20190521000645.16227-3-prsriva02@gmail.com> From: Roberto Sassu Message-ID: Date: Tue, 21 May 2019 09:11:21 +0200 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.3.0 MIME-Version: 1.0 In-Reply-To: <20190521000645.16227-3-prsriva02@gmail.com> Content-Type: text/plain; charset="utf-8"; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.220.96.108] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 5/21/2019 2:06 AM, Prakhar Srivastava wrote: > A buffer(cmdline args) measured into ima cannot be appraised > without already being aware of the buffer contents.Since we Space before 'Since'. > don't know what cmdline args will be passed (or need to validate > what was passed) it is not possible to appraise it. > > Since hashs are non reversible the raw buffer is needed to > recompute the hash. Hashes. > To regenrate the hash of the buffer and appraise the same Regenerate. > the contents of the buffer need to be available. > > A new template field buf is added to the existing ima template > fields, which can be used to store/read the buffer itself. > Two new fields are added to the ima_event_data to carry the > buf and buf_len whenever necessary. > > Updated the process_buffer_measurement call to add the buf > to the ima_event_data. > process_buffer_measurement added in "Add a new ima hook > ima_kexec_cmdline to measure cmdline args" > > - Add a new template field 'buf' to be used to store/read > the buffer data. > - Added two new fields to ima_event_data to hold the buf and > buf_len [Suggested by Roberto] > -Updated process_buffer_meaurement to add the buffer to Space after -. > ima_event_data > > Signed-off-by: Prakhar Srivastava > --- > Documentation/security/IMA-templates.rst | 2 +- > security/integrity/ima/ima.h | 2 ++ > security/integrity/ima/ima_api.c | 4 ++-- > security/integrity/ima/ima_init.c | 2 +- > security/integrity/ima/ima_main.c | 4 +++- > security/integrity/ima/ima_template.c | 2 ++ > security/integrity/ima/ima_template_lib.c | 20 ++++++++++++++++++++ > security/integrity/ima/ima_template_lib.h | 4 ++++ > 8 files changed, 35 insertions(+), 5 deletions(-) > > diff --git a/Documentation/security/IMA-templates.rst b/Documentation/security/IMA-templates.rst > index 2cd0e273cc9a..9cddb66727ee 100644 > --- a/Documentation/security/IMA-templates.rst > +++ b/Documentation/security/IMA-templates.rst > @@ -70,7 +70,7 @@ descriptors by adding their identifier to the format string > prefix is shown only if the hash algorithm is not SHA1 or MD5); > - 'n-ng': the name of the event, without size limitations; > - 'sig': the file signature. ; instead of . > - Keep the new line. Apart from that, the patch looks good to me. Reviewed-by: Roberto Sassu Roberto > + - 'buf': the buffer data that was used to generate the hash without size limitations. > > Below, there is the list of defined template descriptors: > > diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h > index 226a26d8de09..4a82541dc3b6 100644 > --- a/security/integrity/ima/ima.h > +++ b/security/integrity/ima/ima.h > @@ -65,6 +65,8 @@ struct ima_event_data { > struct evm_ima_xattr_data *xattr_value; > int xattr_len; > const char *violation; > + const void *buf; > + int buf_len; > }; > > /* IMA template field data definition */ > diff --git a/security/integrity/ima/ima_api.c b/security/integrity/ima/ima_api.c > index 800d965232e5..c12f1cd38f8f 100644 > --- a/security/integrity/ima/ima_api.c > +++ b/security/integrity/ima/ima_api.c > @@ -134,7 +134,7 @@ void ima_add_violation(struct file *file, const unsigned char *filename, > struct ima_template_entry *entry; > struct inode *inode = file_inode(file); > struct ima_event_data event_data = {iint, file, filename, NULL, 0, > - cause}; > + cause, NULL, 0}; > int violation = 1; > int result; > > @@ -286,7 +286,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint, > struct inode *inode = file_inode(file); > struct ima_template_entry *entry; > struct ima_event_data event_data = {iint, file, filename, xattr_value, > - xattr_len, NULL}; > + xattr_len, NULL, NULL, 0}; > int violation = 0; > > if (iint->measured_pcrs & (0x1 << pcr)) > diff --git a/security/integrity/ima/ima_init.c b/security/integrity/ima/ima_init.c > index 6c9295449751..0c34d3100b5b 100644 > --- a/security/integrity/ima/ima_init.c > +++ b/security/integrity/ima/ima_init.c > @@ -50,7 +50,7 @@ static int __init ima_add_boot_aggregate(void) > struct ima_template_entry *entry; > struct integrity_iint_cache tmp_iint, *iint = &tmp_iint; > struct ima_event_data event_data = {iint, NULL, boot_aggregate_name, > - NULL, 0, NULL}; > + NULL, 0, NULL, NULL, 0}; > int result = -ENOMEM; > int violation = 0; > struct { > diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c > index a88c28918a63..6c5691b65b84 100644 > --- a/security/integrity/ima/ima_main.c > +++ b/security/integrity/ima/ima_main.c > @@ -594,7 +594,7 @@ static void process_buffer_measurement(const void *buf, int size, > struct ima_template_entry *entry = NULL; > struct integrity_iint_cache tmp_iint, *iint = &tmp_iint; > struct ima_event_data event_data = {iint, NULL, NULL, > - NULL, 0, NULL}; > + NULL, 0, NULL, NULL, 0}; > struct { > struct ima_digest_data hdr; > char digest[IMA_MAX_DIGEST_SIZE]; > @@ -611,6 +611,8 @@ static void process_buffer_measurement(const void *buf, int size, > memset(&hash, 0, sizeof(hash)); > > event_data.filename = eventname; > + event_data.buf = buf; > + event_data.buf_len = size; > > iint->ima_hash = &hash.hdr; > iint->ima_hash->algo = ima_hash_algo; > diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c > index b631b8bc7624..a76d1c04162a 100644 > --- a/security/integrity/ima/ima_template.c > +++ b/security/integrity/ima/ima_template.c > @@ -43,6 +43,8 @@ static const struct ima_template_field supported_fields[] = { > .field_show = ima_show_template_string}, > {.field_id = "sig", .field_init = ima_eventsig_init, > .field_show = ima_show_template_sig}, > + {.field_id = "buf", .field_init = ima_eventbuf_init, > + .field_show = ima_show_template_buf}, > }; > #define MAX_TEMPLATE_NAME_LEN 15 > > diff --git a/security/integrity/ima/ima_template_lib.c b/security/integrity/ima/ima_template_lib.c > index 513b457ae900..43d1404141c1 100644 > --- a/security/integrity/ima/ima_template_lib.c > +++ b/security/integrity/ima/ima_template_lib.c > @@ -162,6 +162,12 @@ void ima_show_template_sig(struct seq_file *m, enum ima_show_type show, > ima_show_template_field_data(m, show, DATA_FMT_HEX, field_data); > } > > +void ima_show_template_buf(struct seq_file *m, enum ima_show_type show, > + struct ima_field_data *field_data) > +{ > + ima_show_template_field_data(m, show, DATA_FMT_HEX, field_data); > +} > + > /** > * ima_parse_buf() - Parses lengths and data from an input buffer > * @bufstartp: Buffer start address. > @@ -389,3 +395,17 @@ int ima_eventsig_init(struct ima_event_data *event_data, > return ima_write_template_field_data(xattr_value, event_data->xattr_len, > DATA_FMT_HEX, field_data); > } > + > +/* > + * ima_eventbuf_init - include the buffer(kexec-cmldine) as part of the > + * template data. > + */ > +int ima_eventbuf_init(struct ima_event_data *event_data, > + struct ima_field_data *field_data) > +{ > + if ((!event_data->buf) || (event_data->buf_len == 0)) > + return 0; > + > + return ima_write_template_field_data(event_data->buf, event_data->buf_len, > + DATA_FMT_HEX, field_data); > +} > diff --git a/security/integrity/ima/ima_template_lib.h b/security/integrity/ima/ima_template_lib.h > index 6a3d8b831deb..f0178bc60c55 100644 > --- a/security/integrity/ima/ima_template_lib.h > +++ b/security/integrity/ima/ima_template_lib.h > @@ -29,6 +29,8 @@ void ima_show_template_string(struct seq_file *m, enum ima_show_type show, > struct ima_field_data *field_data); > void ima_show_template_sig(struct seq_file *m, enum ima_show_type show, > struct ima_field_data *field_data); > +void ima_show_template_buf(struct seq_file *m, enum ima_show_type show, > + struct ima_field_data *field_data); > int ima_parse_buf(void *bufstartp, void *bufendp, void **bufcurp, > int maxfields, struct ima_field_data *fields, int *curfields, > unsigned long *len_mask, int enforce_mask, char *bufname); > @@ -42,4 +44,6 @@ int ima_eventname_ng_init(struct ima_event_data *event_data, > struct ima_field_data *field_data); > int ima_eventsig_init(struct ima_event_data *event_data, > struct ima_field_data *field_data); > +int ima_eventbuf_init(struct ima_event_data *event_data, > + struct ima_field_data *field_data); > #endif /* __LINUX_IMA_TEMPLATE_LIB_H */ > -- HUAWEI TECHNOLOGIES Duesseldorf GmbH, HRB 56063 Managing Director: Bo PENG, Jian LI, Yanli SHI