audit: allow interfield comparison in audit rules
We wish to be able to audit when a uid=500 task accesses a file which is
uid=0. Or vice versa. This patch introduces a new audit filter type
AUDIT_FIELD_COMPARE which takes as an 'enum' which indicates which fields
should be compared. At this point we only define the task->uid vs
inode->uid, but other comparisons can be added.
Signed-off-by: Eric Paris <eparis@redhat.com>
diff --git a/kernel/auditfilter.c b/kernel/auditfilter.c
index f10605c..a6c3f1a 100644
--- a/kernel/auditfilter.c
+++ b/kernel/auditfilter.c
@@ -526,7 +526,6 @@
goto exit_free;
break;
case AUDIT_FILTERKEY:
- err = -EINVAL;
if (entry->rule.filterkey || f->val > AUDIT_MAX_KEY_LEN)
goto exit_free;
str = audit_unpack_string(&bufp, &remain, f->val);
@@ -543,6 +542,10 @@
if (f->val & ~S_IFMT)
goto exit_free;
break;
+ case AUDIT_FIELD_COMPARE:
+ if (f->val > AUDIT_MAX_FIELD_COMPARE)
+ goto exit_free;
+ break;
default:
goto exit_free;
}
