refactor allowlist

[5ec1cff]

kernel: allowlist: remove allow_list_arr and allow_list_bitmap
kernel: allowlist: make current_uid as the only key
kernel: allowlist: rename current_uid to curr_uid to avoid conflict with kernel macro
kernel: allowlist: use hashtable

[Copilot]

Pull request overview

This PR refactors the KernelSU allowlist implementation by replacing the previous linked list + bitmap + fixed array data structures with a Linux kernel hashtable. Additionally, the current_uid field in struct app_profile is renamed to curr_uid to avoid conflicts with a kernel macro of the same name.

Changes:

• Replaced struct list_head allow_list, allow_list_bitmap[PAGE_SIZE], and allow_list_arr[PAGE_SIZE/sizeof(int)] with DEFINE_HASHTABLE(allow_list, ALLOW_LIST_BITS) for O(1) average-case UID lookup
• Renamed struct app_profile::current_uid to curr_uid to avoid shadowing the kernel's current_uid() macro
• Updated all hashtable traversal/modification calls (hash_for_each_*, hash_add_rcu, hlist_*) and removed the now-unnecessary bitmap/array fast-path in __ksu_is_allow_uid

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
kernel/app_profile.h	Renames current_uid to curr_uid in struct app_profile
kernel/allowlist.c	Replaces linked list + bitmap + array with hashtable; updates all traversal and modification logic accordingly

Comments suppressed due to low confidence (1)

kernel/allowlist.c:184

• The count overflow protection check (count == U16_MAX) no longer reflects the true total number of profiles in the allowlist. With the old list_for_each_entry, count accumulated over all entries in the entire list. With hash_for_each_possible, it only counts entries in the same hash bucket as profile->curr_uid. Since hash buckets in a 256-bucket table will typically hold only a small fraction of total entries, this check will essentially never trigger unless there are 65535 entries mapping to the same bucket, which would be an extreme hash collision scenario. The intent was to prevent excessive total profile registrations, but the guard is now effectively non-functional. Consider using a separate global counter or checking the total count differently.

    hash_for_each_possible (allow_list, p, list, profile->curr_uid) {
        ++count;
        if (profile->curr_uid == p->profile.curr_uid) {
            if (strcmp(profile->key, p->profile.key) != 0) {
                pr_warn(
                    "ksu_set_app_profile: key changed: uid=%d orig=%s new=%s\n",
                    profile->curr_uid, p->profile.key, profile->key);
            }
            // found it, just override it all!
            np = (struct perm_data *)kzalloc(sizeof(struct perm_data),
                                             GFP_KERNEL);
            if (!np) {
                result = -ENOMEM;
                goto out_unlock;
            }
            memcpy(&np->profile, profile, sizeof(*profile));
            hlist_replace_rcu(&p->list, &np->list);
            kfree_rcu(p, rcu);
            goto out;
        }
    }

    if (unlikely(count == U16_MAX)) {

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[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

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[Copilot]

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 5 comments.

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Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated 3 comments.

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