v4.19.13 snapshot.
diff --git a/security/apparmor/task.c b/security/apparmor/task.c
new file mode 100644
index 0000000..c6b78a1
--- /dev/null
+++ b/security/apparmor/task.c
@@ -0,0 +1,183 @@
+/*
+ * AppArmor security module
+ *
+ * This file contains AppArmor task related definitions and mediation
+ *
+ * Copyright 2017 Canonical Ltd.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation, version 2 of the
+ * License.
+ *
+ * TODO
+ * If a task uses change_hat it currently does not return to the old
+ * cred or task context but instead creates a new one. Ideally the task
+ * should return to the previous cred if it has not been modified.
+ */
+
+#include "include/cred.h"
+#include "include/task.h"
+
+/**
+ * aa_get_task_label - Get another task's label
+ * @task: task to query (NOT NULL)
+ *
+ * Returns: counted reference to @task's label
+ */
+struct aa_label *aa_get_task_label(struct task_struct *task)
+{
+ struct aa_label *p;
+
+ rcu_read_lock();
+ p = aa_get_newest_label(__aa_task_raw_label(task));
+ rcu_read_unlock();
+
+ return p;
+}
+
+/**
+ * aa_replace_current_label - replace the current tasks label
+ * @label: new label (NOT NULL)
+ *
+ * Returns: 0 or error on failure
+ */
+int aa_replace_current_label(struct aa_label *label)
+{
+ struct aa_label *old = aa_current_raw_label();
+ struct aa_task_ctx *ctx = task_ctx(current);
+ struct cred *new;
+
+ AA_BUG(!label);
+
+ if (old == label)
+ return 0;
+
+ if (current_cred() != current_real_cred())
+ return -EBUSY;
+
+ new = prepare_creds();
+ if (!new)
+ return -ENOMEM;
+
+ if (ctx->nnp && label_is_stale(ctx->nnp)) {
+ struct aa_label *tmp = ctx->nnp;
+
+ ctx->nnp = aa_get_newest_label(tmp);
+ aa_put_label(tmp);
+ }
+ if (unconfined(label) || (labels_ns(old) != labels_ns(label)))
+ /*
+ * if switching to unconfined or a different label namespace
+ * clear out context state
+ */
+ aa_clear_task_ctx_trans(task_ctx(current));
+
+ /*
+ * be careful switching cred label, when racing replacement it
+ * is possible that the cred labels's->proxy->label is the reference
+ * keeping @label valid, so make sure to get its reference before
+ * dropping the reference on the cred's label
+ */
+ aa_get_label(label);
+ aa_put_label(cred_label(new));
+ cred_label(new) = label;
+
+ commit_creds(new);
+ return 0;
+}
+
+
+/**
+ * aa_set_current_onexec - set the tasks change_profile to happen onexec
+ * @label: system label to set at exec (MAYBE NULL to clear value)
+ * @stack: whether stacking should be done
+ * Returns: 0 or error on failure
+ */
+int aa_set_current_onexec(struct aa_label *label, bool stack)
+{
+ struct aa_task_ctx *ctx = task_ctx(current);
+
+ aa_get_label(label);
+ aa_put_label(ctx->onexec);
+ ctx->onexec = label;
+ ctx->token = stack;
+
+ return 0;
+}
+
+/**
+ * aa_set_current_hat - set the current tasks hat
+ * @label: label to set as the current hat (NOT NULL)
+ * @token: token value that must be specified to change from the hat
+ *
+ * Do switch of tasks hat. If the task is currently in a hat
+ * validate the token to match.
+ *
+ * Returns: 0 or error on failure
+ */
+int aa_set_current_hat(struct aa_label *label, u64 token)
+{
+ struct aa_task_ctx *ctx = task_ctx(current);
+ struct cred *new;
+
+ new = prepare_creds();
+ if (!new)
+ return -ENOMEM;
+ AA_BUG(!label);
+
+ if (!ctx->previous) {
+ /* transfer refcount */
+ ctx->previous = cred_label(new);
+ ctx->token = token;
+ } else if (ctx->token == token) {
+ aa_put_label(cred_label(new));
+ } else {
+ /* previous_profile && ctx->token != token */
+ abort_creds(new);
+ return -EACCES;
+ }
+
+ cred_label(new) = aa_get_newest_label(label);
+ /* clear exec on switching context */
+ aa_put_label(ctx->onexec);
+ ctx->onexec = NULL;
+
+ commit_creds(new);
+ return 0;
+}
+
+/**
+ * aa_restore_previous_label - exit from hat context restoring previous label
+ * @token: the token that must be matched to exit hat context
+ *
+ * Attempt to return out of a hat to the previous label. The token
+ * must match the stored token value.
+ *
+ * Returns: 0 or error of failure
+ */
+int aa_restore_previous_label(u64 token)
+{
+ struct aa_task_ctx *ctx = task_ctx(current);
+ struct cred *new;
+
+ if (ctx->token != token)
+ return -EACCES;
+ /* ignore restores when there is no saved label */
+ if (!ctx->previous)
+ return 0;
+
+ new = prepare_creds();
+ if (!new)
+ return -ENOMEM;
+
+ aa_put_label(cred_label(new));
+ cred_label(new) = aa_get_newest_label(ctx->previous);
+ AA_BUG(!cred_label(new));
+ /* clear exec && prev information when restoring to previous context */
+ aa_clear_task_ctx_trans(ctx);
+
+ commit_creds(new);
+
+ return 0;
+}