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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120// 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);}