[PATCH v2 3/4] ima: limit secure boot feedback scope for appraise

Bruno Meneguele
2020-09-04T19:41:31Z

Only prompt the unknown/invalid appraisal option if secureboot is enabled and
if the current state differentiates from the original one.

Signed-off-by: Bruno Meneguele <bmeneg@redhat.com>
---
Changelog:
v2:
- update commit message (Mimi)
- work with a temporary var instead of directly with ima_appraise (Mimi)

security/integrity/ima/ima_appraise.c | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/security/integrity/ima/ima_appraise.c b/security/integrity/ima/ima_appraise.c
index 2193b51c2743..d17808245592 100644
--- a/security/integrity/ima/ima_appraise.c
+++ b/security/integrity/ima/ima_appraise.c
@@ -19,22 +19,29 @@
static int __init default_appraise_setup(char *str)
{
#ifdef CONFIG_IMA_APPRAISE_BOOTPARAM
- if (arch_ima_get_secureboot()) {
- pr_info("Secure boot enabled: ignoring ima_appraise=%s boot parameter option",
- str);
- return 1;
- }
+ bool sb_state = arch_ima_get_secureboot();
+ int appraisal_state = ima_appraise;

if (strncmp(str, "off", 3) == 0)
- ima_appraise = 0;
+ appraisal_state = 0;
else if (strncmp(str, "log", 3) == 0)
- ima_appraise = IMA_APPRAISE_LOG;
+ appraisal_state = IMA_APPRAISE_LOG;
else if (strncmp(str, "fix", 3) == 0)
- ima_appraise = IMA_APPRAISE_FIX;
+ appraisal_state = IMA_APPRAISE_FIX;
else if (strncmp(str, "enforce", 7) == 0)
- ima_appraise = IMA_APPRAISE_ENFORCE;
+ appraisal_state = IMA_APPRAISE_ENFORCE;
else
pr_err("invalid \"%s\" appraise option", str);
+
+ /* If appraisal state was changed, but secure boot is enabled,
+ * keep its default */
+ if (sb_state) {
+ if (!(appraisal_state & IMA_APPRAISE_ENFORCE))
+ pr_info("Secure boot enabled: ignoring ima_appraise=%s option",
+ str);
+ else
+ ima_appraise = appraisal_state;
+ }
#endif
return 1;
}
--
2.26.2