[PATCH v3 21/22] ima: measure and appraise the IMA policy itself

[Dmitry Kasatkin]

On Wed, Feb 3, 2016 at 9:06 PM, Mimi Zohar <zohar at linux.vnet.ibm.com> wrote:
> Add support for measuring and appraising the IMA policy itself.
>
> Signed-off-by: Mimi Zohar <zohar at linux.vnet.ibm.com>

Acked-by: Dmitry Kasatkin <dmitry.kasatkin at huawei.com>

But from Documentation/CodingStyle

if (condition)
    do_this();
else
    do_that();

This does not apply if only one branch of a conditional statement is a single
statement; in the latter case use braces in both branches:

if (condition) {
     do_this();
     do_that();
} else {
     otherwise();
}


You have similar issue in other patches as well...

Dmitry

> ---
>  security/integrity/ima/ima.h        |  2 ++
>  security/integrity/ima/ima_fs.c     |  9 ++++++++-
>  security/integrity/ima/ima_main.c   |  3 +++
>  security/integrity/ima/ima_policy.c | 10 +++++++++-
>  4 files changed, 22 insertions(+), 2 deletions(-)
>
> diff --git a/security/integrity/ima/ima.h b/security/integrity/ima/ima.h
> index 832e62a..6685968 100644
> --- a/security/integrity/ima/ima.h
> +++ b/security/integrity/ima/ima.h
> @@ -149,6 +149,7 @@ enum ima_hooks {
>         FIRMWARE_CHECK,
>         KEXEC_CHECK,
>         INITRAMFS_CHECK,
> +       POLICY_CHECK,
>         MAX_CHECK
>  };
>
> @@ -191,6 +192,7 @@ int ima_policy_show(struct seq_file *m, void *v);
>  #define IMA_APPRAISE_LOG       0x04
>  #define IMA_APPRAISE_MODULES   0x08
>  #define IMA_APPRAISE_FIRMWARE  0x10
> +#define IMA_APPRAISE_POLICY    0x20
>
>  #ifdef CONFIG_IMA_APPRAISE
>  int ima_appraise_measurement(enum ima_hooks func,
> diff --git a/security/integrity/ima/ima_fs.c b/security/integrity/ima/ima_fs.c
> index 00ccd67..7b15e80 100644
> --- a/security/integrity/ima/ima_fs.c
> +++ b/security/integrity/ima/ima_fs.c
> @@ -325,7 +325,14 @@ static ssize_t ima_write_policy(struct file *file, const char __user *buf,
>
>         if (data[0] == '/')
>                 result = ima_read_policy(data);
> -       else
> +       else if (ima_appraise & IMA_APPRAISE_POLICY) {
> +               pr_err("IMA: signed policy required\n");
> +               integrity_audit_msg(AUDIT_INTEGRITY_STATUS, NULL, NULL,
> +                                   "policy_update", "signed policy required",
> +                                   1, 0);
> +               if (ima_appraise & IMA_APPRAISE_ENFORCE)
> +                       result = -EACCES;
> +       } else
>                 result = ima_parse_add_rule(data);
>         mutex_unlock(&ima_write_mutex);
>  out_free:
> diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
> index ccf9526..497a6f2 100644
> --- a/security/integrity/ima/ima_main.c
> +++ b/security/integrity/ima/ima_main.c
> @@ -386,6 +386,9 @@ int ima_post_read_file(struct file *file, void *buf, loff_t size,
>         case READING_KEXEC_INITRAMFS:
>                 func = INITRAMFS_CHECK;
>                 break;
> +       case READING_POLICY:
> +               func = POLICY_CHECK;
> +               break;
>         default:
>                 func = FILE_CHECK;
>                 break;
> diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
> index d02560e..39a811a 100644
> --- a/security/integrity/ima/ima_policy.c
> +++ b/security/integrity/ima/ima_policy.c
> @@ -114,6 +114,7 @@ static struct ima_rule_entry default_measurement_rules[] = {
>          .uid = GLOBAL_ROOT_UID, .flags = IMA_FUNC | IMA_INMASK | IMA_UID},
>         {.action = MEASURE, .func = MODULE_CHECK, .flags = IMA_FUNC},
>         {.action = MEASURE, .func = FIRMWARE_CHECK, .flags = IMA_FUNC},
> +       {.action = MEASURE, .func = POLICY_CHECK, .flags = IMA_FUNC},
>  };
>
>  static struct ima_rule_entry default_appraise_rules[] = {
> @@ -616,6 +617,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
>                                 entry->func = KEXEC_CHECK;
>                         else if (strcmp(args[0].from, "INITRAMFS_CHECK") == 0)
>                                 entry->func = INITRAMFS_CHECK;
> +                       else if (strcmp(args[0].from, "POLICY_CHECK") == 0)
> +                               entry->func = POLICY_CHECK;
>                         else
>                                 result = -EINVAL;
>                         if (!result)
> @@ -774,6 +777,8 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
>                 temp_ima_appraise |= IMA_APPRAISE_MODULES;
>         else if (entry->func == FIRMWARE_CHECK)
>                 temp_ima_appraise |= IMA_APPRAISE_FIRMWARE;
> +       else if (entry->func == POLICY_CHECK)
> +               temp_ima_appraise |= IMA_APPRAISE_POLICY;
>         audit_log_format(ab, "res=%d", !result);
>         audit_log_end(ab);
>         return result;
> @@ -860,7 +865,7 @@ static char *mask_tokens[] = {
>  enum {
>         func_file = 0, func_mmap, func_bprm,
>         func_module, func_firmware, func_post,
> -       func_kexec, func_initramfs
> +       func_kexec, func_initramfs, func_policy
>  };
>
>  static char *func_tokens[] = {
> @@ -940,6 +945,9 @@ static void policy_func_show(struct seq_file *m, enum ima_hooks func)
>         case INITRAMFS_CHECK:
>                 seq_printf(m, pt(Opt_func), ft(func_initramfs));
>                 break;
> +       case POLICY_CHECK:
> +               seq_printf(m, pt(Opt_func), ft(func_policy));
> +               break;
>         default:
>                 snprintf(tbuf, sizeof(tbuf), "%d", func);
>                 seq_printf(m, pt(Opt_func), tbuf);
> --
> 2.1.0
>



-- 
Thanks,
Dmitry