[PATCH 2/5] audit: complex interfield comparison helper

Eric Paris
2012-01-04T20:47:10Z

Rather than code the same loop over and over implement a helper function which
uses some pointer magic to make it generic enough to be used numerous places
as we implement more audit interfield comparisons

Signed-off-by: Eric Paris <eparis@redhat.com>
---
kernel/auditsc.c | 50 +++++++++++++++++++++++++++++++++++++++-----------
1 files changed, 39 insertions(+), 11 deletions(-)

diff --git a/kernel/auditsc.c b/kernel/auditsc.c
index efb1763..45c13c5 100644
--- a/kernel/auditsc.c
+++ b/kernel/auditsc.c
@@ -463,25 +463,53 @@ static int match_tree_refs(struct audit_context *ctx, struct audit_tree *tree)
return 0;
}

+static int audit_compare_id(uid_t uid1,
+ struct audit_names *name,
+ unsigned long name_offset,
+ struct audit_field *f,
+ struct audit_context *ctx)
+{
+ struct audit_names *n;
+ unsigned long addr;
+ uid_t uid2;
+ int rc;
+
+ if (name) {
+ addr = (unsigned long)name;
+ addr += name_offset;
+
+ uid2 = *(uid_t *)addr;
+ rc = audit_comparator(uid1, f->op, uid2);
+ if (rc)
+ return rc;
+ }
+
+ if (ctx) {
+ list_for_each_entry(n, &ctx->names_list, list) {
+ addr = (unsigned long)n;
+ addr += name_offset;
+
+ uid2 = *(uid_t *)addr;
+
+ rc = audit_comparator(uid1, f->op, uid2);
+ if (rc)
+ return rc;
+ }
+ }
+ return 0;
+}
+
static int audit_field_compare(struct task_struct *tsk,
const struct cred *cred,
struct audit_field *f,
struct audit_context *ctx,
struct audit_names *name)
{
- struct audit_names *n;
-
switch (f->val) {
case AUDIT_COMPARE_UID_TO_OBJ_UID:
- if (name) {
- return audit_comparator(cred->uid, f->op, name->uid);
- } else if (ctx) {
- list_for_each_entry(n, &ctx->names_list, list) {
- if (audit_comparator(cred->uid, f->op, n->uid))
- return 1;
- }
- }
- break;
+ return audit_compare_id(cred->uid,
+ name, offsetof(struct audit_names, uid),
+ f, ctx);