// SPDX-License-Identifier: GPL-2.0/* Copyright (c) 2026 Christian Brauner <brauner@kernel.org> */#include <linux/init.h>#include <linux/rcupdate.h>#include <linux/refcount.h>#include <linux/sched.h>#include <linux/sched/coredump.h>#include <linux/sched/exec_state.h>#include <linux/sched/signal.h>#include <linux/slab.h>#include <linux/user_namespace.h> static struct kmem_cache *task_exec_state_cachep; static void __free_task_exec_state(struct rcu_head *rcu){	struct task_exec_state *exec_state = container_of(rcu, struct task_exec_state, rcu); 	put_user_ns(exec_state->user_ns);	kmem_cache_free(task_exec_state_cachep, exec_state);} void put_task_exec_state(struct task_exec_state *exec_state){	if (exec_state && refcount_dec_and_test(&exec_state->count))		call_rcu(&exec_state->rcu, __free_task_exec_state);} struct task_exec_state *alloc_task_exec_state(struct user_namespace *user_ns){	struct task_exec_state *exec_state; 	exec_state = kmem_cache_alloc(task_exec_state_cachep, GFP_KERNEL);	if (!exec_state)		return NULL;	refcount_set(&exec_state->count, 1);	exec_state->dumpable = TASK_DUMPABLE_OFF;	exec_state->user_ns = get_user_ns(user_ns);	return exec_state;} struct task_exec_state *task_exec_state_rcu(const struct task_struct *tsk){	struct task_exec_state *exec_state; 	exec_state = rcu_dereference_check(tsk->exec_state,					   lockdep_is_held(&tsk->alloc_lock));	WARN_ON_ONCE(!exec_state);	return exec_state;} struct task_exec_state *task_exec_state_replace(struct task_struct *tsk,						struct task_exec_state *exec_state){	/*	 * Updates must hold both locks so callers needing a consistent	 * snapshot of mm + dumpability are covered.	 */	lockdep_assert_held(&tsk->alloc_lock);	lockdep_assert_held_write(&tsk->signal->exec_update_lock); 	return rcu_replace_pointer(tsk->exec_state, exec_state, true);} /* * The non-CLONE_VM clone path: allocate a fresh exec_state and * inherit the parent's dumpable mode and user_ns reference.  CLONE_VM * siblings refcount-share via copy_exec_state() in fork.c; only this * path and execve() ever allocate. */int task_exec_state_copy(struct task_struct *tsk){	struct task_exec_state *src, *dst; 	src = rcu_dereference_protected(current->exec_state, true);	dst = alloc_task_exec_state(src->user_ns);	if (!dst)		return -ENOMEM;	dst->dumpable = READ_ONCE(src->dumpable);	rcu_assign_pointer(tsk->exec_state, dst);	return 0;} /* * Store TASK_DUMPABLE_* on current->exec_state.  All callers * (commit_creds, begin_new_exec, prctl(PR_SET_DUMPABLE)) act on the * running task, which guarantees ->exec_state is allocated and cannot * be replaced under us. */void task_exec_state_set_dumpable(enum task_dumpable value){	struct task_exec_state *exec_state; 	if (WARN_ON_ONCE(value > TASK_DUMPABLE_ROOT))		value = TASK_DUMPABLE_OFF; 	exec_state = rcu_dereference_protected(current->exec_state, true);	/* mm-less tasks share init_task's exec_state; never mutate it */	if (WARN_ON_ONCE(exec_state == &init_task_exec_state))		return;	WRITE_ONCE(exec_state->dumpable, value);} enum task_dumpable task_exec_state_get_dumpable(struct task_struct *task){	struct task_exec_state *exec_state; 	guard(rcu)();	exec_state = rcu_dereference(task->exec_state);	return READ_ONCE(exec_state->dumpable);} void __init exec_state_init(void){	task_exec_state_cachep = kmem_cache_create("task_exec_state",			sizeof(struct task_exec_state), 0,			SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT,			NULL);}