diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 4 | ||||
| -rw-r--r-- | Documentation/security/IMA-templates.txt | 29 | ||||
| -rw-r--r-- | security/integrity/ima/ima_template.c | 39 |
3 files changed, 52 insertions, 20 deletions
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: <min_file_size> 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='. diff --git a/security/integrity/ima/ima_template.c b/security/integrity/ima/ima_template.c index 65117ba06809..0b7404ebfa80 100644 --- a/security/integrity/ima/ima_template.c +++ b/security/integrity/ima/ima_template.c @@ -24,6 +24,7 @@ static struct ima_template_desc defined_templates[] = { {.name = IMA_TEMPLATE_IMA_NAME, .fmt = IMA_TEMPLATE_IMA_FMT}, {.name = "ima-ng", .fmt = "d-ng|n-ng"}, {.name = "ima-sig", .fmt = "d-ng|n-ng|sig"}, + {.name = "", .fmt = ""}, /* placeholder for a custom format */ }; static struct ima_template_field supported_fields[] = { @@ -41,12 +42,18 @@ static struct ima_template_field supported_fields[] = { static struct ima_template_desc *ima_template; static struct ima_template_desc *lookup_template_desc(const char *name); +static int template_desc_init_fields(const char *template_fmt, + struct ima_template_field ***fields, + int *num_fields); static int __init ima_template_setup(char *str) { struct ima_template_desc *template_desc; int template_len = strlen(str); + if (ima_template) + return 1; + /* * Verify that a template with the supplied name exists. * If not, use CONFIG_IMA_DEFAULT_TEMPLATE. @@ -73,6 +80,25 @@ static int __init ima_template_setup(char *str) } __setup("ima_template=", ima_template_setup); +static int __init ima_template_fmt_setup(char *str) +{ + int num_templates = ARRAY_SIZE(defined_templates); + + if (ima_template) + return 1; + + if (template_desc_init_fields(str, NULL, NULL) < 0) { + pr_err("format string '%s' not valid, using template %s\n", + str, CONFIG_IMA_DEFAULT_TEMPLATE); + return 1; + } + + defined_templates[num_templates - 1].fmt = str; + ima_template = defined_templates + num_templates - 1; + return 1; +} +__setup("ima_template_fmt=", ima_template_fmt_setup); + static struct ima_template_desc *lookup_template_desc(const char *name) { int i; @@ -146,12 +172,15 @@ static int template_desc_init_fields(const char *template_fmt, } } - *fields = kmalloc_array(i, sizeof(*fields), GFP_KERNEL); - if (*fields == NULL) - return -ENOMEM; + if (fields && num_fields) { + *fields = kmalloc_array(i, sizeof(*fields), GFP_KERNEL); + if (*fields == NULL) + return -ENOMEM; + + memcpy(*fields, found_fields, i * sizeof(*fields)); + *num_fields = i; + } - memcpy(*fields, found_fields, i * sizeof(*fields)); - *num_fields = i; return 0; } |