ima: support for kexec image and initramfs
Add IMA policy support for measuring/appraising the kexec image and
initramfs. Two new IMA policy identifiers KEXEC_KERNEL_CHECK and
KEXEC_INITRAMFS_CHECK are defined.
Example policy rules:
measure func=KEXEC_KERNEL_CHECK
appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig
measure func=KEXEC_INITRAMFS_CHECK
appraise func=KEXEC_INITRAMFS_CHECK appraise_type=imasig
Moving the enumeration to the vfs layer simplified the patches, allowing
the IMA changes, for the most part, to be separated from the other
changes. Unfortunately, passing either a kernel_read_file_id or a
ima_hooks enumeration within IMA is messy.
Option 1: duplicate kernel_read_file enumeration in ima_hooks
enum kernel_read_file_id {
...
READING_KEXEC_IMAGE,
READING_KEXEC_INITRAMFS,
READING_MAX_ID
enum ima_hooks {
...
KEXEC_KERNEL_CHECK
KEXEC_INITRAMFS_CHECK
Option 2: define ima_hooks as extension of kernel_read_file
eg: enum ima_hooks {
FILE_CHECK = READING_MAX_ID,
MMAP_CHECK,
In order to pass both kernel_read_file_id and ima_hooks values, we
would need to specify a struct containing a union.
struct caller_id {
union {
enum ima_hooks func_id;
enum kernel_read_file_id read_id;
};
};
Option 3: incorportate the ima_hooks enumeration into kernel_read_file_id,
perhaps changing the enumeration name.
For now, duplicate the new READING_KEXEC_IMAGE/INITRAMFS in the ima_hooks.
Changelog v4:
- replaced switch statement with a kernel_read_file_id to an ima_hooks
id mapping array - Dmitry
- renamed ima_hook tokens KEXEC_CHECK and INITRAMFS_CHECK to
KEXEC_KERNEL_CHECK and KEXEC_INITRAMFS_CHECK respectively - Dave Young
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: Petko Manolov <petkan@mip-labs.com>
Acked-by: Dmitry Kasatkin <dmitry.kasatkin@huawei.com>
Cc: Dave Young <dyoung@redhat.com>
diff --git a/security/integrity/ima/ima_main.c b/security/integrity/ima/ima_main.c
index 5da0b9c..f764881 100644
--- a/security/integrity/ima/ima_main.c
+++ b/security/integrity/ima/ima_main.c
@@ -339,6 +339,13 @@
return 0;
}
+static int read_idmap[READING_MAX_ID] = {
+ [READING_FIRMWARE] = FIRMWARE_CHECK,
+ [READING_MODULE] = MODULE_CHECK,
+ [READING_KEXEC_IMAGE] = KEXEC_KERNEL_CHECK,
+ [READING_KEXEC_INITRAMFS] = KEXEC_INITRAMFS_CHECK,
+};
+
/**
* ima_post_read_file - in memory collect/appraise/audit measurement
* @file: pointer to the file to be measured/appraised/audit
@@ -355,7 +362,7 @@
int ima_post_read_file(struct file *file, void *buf, loff_t size,
enum kernel_read_file_id read_id)
{
- enum ima_hooks func = FILE_CHECK;
+ enum ima_hooks func;
if (!file && read_id == READING_FIRMWARE) {
if ((ima_appraise & IMA_APPRAISE_FIRMWARE) &&
@@ -373,11 +380,7 @@
return 0;
}
- if (read_id == READING_FIRMWARE)
- func = FIRMWARE_CHECK;
- else if (read_id == READING_MODULE)
- func = MODULE_CHECK;
-
+ func = read_idmap[read_id] ?: FILE_CHECK;
return process_measurement(file, buf, size, MAY_READ, func, 0);
}