On 6/26/20 3:38 PM, Tyler Hicks wrote:
Use ima_validate_rule() to ensure that the combination of a hook
function and the keyrings conditional is valid and that the keyrings
conditional is not specified without an explicit KEY_CHECK func
conditional. This is a code cleanup and has no user-facing change.
In addition to checking for func=KEY_CHECK and the keyrings conditional,
the patch also validates the flags for other IMA hooks (such as
KEXEC_KERNEL_CHECK, POLICY_CHECK, etc.) Would be good to mention that in
the patch description.
-lakshmi
Signed-off-by: Tyler Hicks <tyhicks@xxxxxxxxxxxxxxxxxxx>
---
* v2
- Allowed IMA_DIGSIG_REQUIRED, IMA_PERMIT_DIRECTIO,
IMA_MODSIG_ALLOWED, and IMA_CHECK_BLACKLIST conditionals to be
present in the rule entry flags for non-buffer hook functions.
security/integrity/ima/ima_policy.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/security/integrity/ima/ima_policy.c b/security/integrity/ima/ima_policy.c
index 8cdca2399d59..43d49ad958fb 100644
--- a/security/integrity/ima/ima_policy.c
+++ b/security/integrity/ima/ima_policy.c
@@ -1000,6 +1000,15 @@ static bool ima_validate_rule(struct ima_rule_entry *entry)
case KEXEC_KERNEL_CHECK:
case KEXEC_INITRAMFS_CHECK:
case POLICY_CHECK:
+ if (entry->flags & ~(IMA_FUNC | IMA_MASK | IMA_FSMAGIC |
+ IMA_UID | IMA_FOWNER | IMA_FSUUID |
+ IMA_INMASK | IMA_EUID | IMA_PCR |
+ IMA_FSNAME | IMA_DIGSIG_REQUIRED |
+ IMA_PERMIT_DIRECTIO |
+ IMA_MODSIG_ALLOWED |
+ IMA_CHECK_BLACKLIST))
+ return false;
+
break;
case KEXEC_CMDLINE:
if (entry->action & ~(MEASURE | DONT_MEASURE))
@@ -1027,7 +1036,8 @@ static bool ima_validate_rule(struct ima_rule_entry *entry)
default:
return false;
}
- }
+ } else if (entry->flags & IMA_KEYRINGS)
+ return false;
return true;
}
@@ -1209,7 +1219,6 @@ static int ima_parse_rule(char *rule, struct ima_rule_entry *entry)
keyrings_len = strlen(args[0].from) + 1;
if ((entry->keyrings) ||
- (entry->func != KEY_CHECK) ||
(keyrings_len < 2)) {
result = -EINVAL;
break;
