From c2426d2ad5027397342107b7ff094aa9b234acb8 Mon Sep 17 00:00:00 2001 From: Roberto Sassu Date: Mon, 13 Oct 2014 14:08:42 +0200 Subject: ima: added support for new kernel cmdline parameter ima_template_fmt This patch allows users to provide a custom template format through the new kernel command line parameter 'ima_template_fmt'. If the supplied format is not valid, IMA uses the default template descriptor. Changelog: - v3: - added check for 'fields' and 'num_fields' in template_desc_init_fields() (suggested by Mimi Zohar) - v2: - using template_desc_init_fields() to validate a format string (Roberto Sassu) - updated documentation by stating that only the chosen template descriptor is initialized (Roberto Sassu) - v1: - simplified code of ima_template_fmt_setup() (Roberto Sassu, suggested by Mimi Zohar) Signed-off-by: Roberto Sassu Signed-off-by: Mimi Zohar --- Documentation/kernel-parameters.txt | 4 ++++ Documentation/security/IMA-templates.txt | 29 ++++++++++++++--------------- 2 files changed, 18 insertions(+), 15 deletions(-) (limited to 'Documentation') diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 802a3fd9e485..06b2cd5739dd 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1318,6 +1318,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. Formats: { "ima" | "ima-ng" } Default: "ima-ng" + ima_template_fmt= + [IMA] Define a custom template format. + Format: { "field1|...|fieldN" } + ima.ahash_minsize= [IMA] Minimum file size for asynchronous hash usage Format: Set the minimal file size for using asynchronous hash. diff --git a/Documentation/security/IMA-templates.txt b/Documentation/security/IMA-templates.txt index a4e102dddfea..839b5dad9226 100644 --- a/Documentation/security/IMA-templates.txt +++ b/Documentation/security/IMA-templates.txt @@ -27,25 +27,22 @@ Managing templates with these structures is very simple. To support a new data type, developers define the field identifier and implement two functions, init() and show(), respectively to generate and display measurement entries. Defining a new template descriptor requires -specifying the template format, a string of field identifiers separated -by the '|' character. While in the current implementation it is possible -to define new template descriptors only by adding their definition in the -template specific code (ima_template.c), in a future version it will be -possible to register a new template on a running kernel by supplying to IMA -the desired format string. In this version, IMA initializes at boot time -all defined template descriptors by translating the format into an array -of template fields structures taken from the set of the supported ones. +specifying the template format (a string of field identifiers separated +by the '|' character) through the 'ima_template_fmt' kernel command line +parameter. At boot time, IMA initializes the chosen template descriptor +by translating the format into an array of template fields structures taken +from the set of the supported ones. After the initialization step, IMA will call ima_alloc_init_template() (new function defined within the patches for the new template management mechanism) to generate a new measurement entry by using the template descriptor chosen through the kernel configuration or through the newly -introduced 'ima_template=' kernel command line parameter. It is during this -phase that the advantages of the new architecture are clearly shown: -the latter function will not contain specific code to handle a given template -but, instead, it simply calls the init() method of the template fields -associated to the chosen template descriptor and store the result (pointer -to allocated data and data length) in the measurement entry structure. +introduced 'ima_template' and 'ima_template_fmt' kernel command line parameters. +It is during this phase that the advantages of the new architecture are +clearly shown: the latter function will not contain specific code to handle +a given template but, instead, it simply calls the init() method of the template +fields associated to the chosen template descriptor and store the result +(pointer to allocated data and data length) in the measurement entry structure. The same mechanism is employed to display measurements entries. The functions ima[_ascii]_measurements_show() retrieve, for each entry, @@ -86,4 +83,6 @@ currently the following methods are supported: - select a template descriptor among those supported in the kernel configuration ('ima-ng' is the default choice); - specify a template descriptor name from the kernel command line through - the 'ima_template=' parameter. + the 'ima_template=' parameter; + - register a new template descriptor with custom format through the kernel + command line parameter 'ima_template_fmt='. -- cgit v1.2.3-59-g8ed1b