On 16-02-03 14:06:29, Mimi Zohar wrote:
> Add support for measuring and appraising the IMA policy itself.
>
> Signed-off-by: Mimi Zohar <zo...@linux.vnet.ibm.com>
Acked-by: Petko Manolov <pet...@mip-labs.com>
> ---
> 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
>
> --
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