diff options
| -rw-r--r-- | security/yama/yama_lsm.c | 47 |
1 files changed, 24 insertions, 23 deletions
diff --git a/security/yama/yama_lsm.c b/security/yama/yama_lsm.c index b4c29848b49..70cd85e3ba3 100644 --- a/security/yama/yama_lsm.c +++ b/security/yama/yama_lsm.c @@ -30,6 +30,7 @@ struct ptrace_relation { struct task_struct *tracer; struct task_struct *tracee; struct list_head node; + struct rcu_head rcu; }; static LIST_HEAD(ptracer_relations); @@ -48,32 +49,31 @@ static DEFINE_SPINLOCK(ptracer_relations_lock); static int yama_ptracer_add(struct task_struct *tracer, struct task_struct *tracee) { - int rc = 0; - struct ptrace_relation *added; - struct ptrace_relation *entry, *relation = NULL; + struct ptrace_relation *relation, *added; added = kmalloc(sizeof(*added), GFP_KERNEL); if (!added) return -ENOMEM; + added->tracee = tracee; + added->tracer = tracer; + spin_lock_bh(&ptracer_relations_lock); - list_for_each_entry(entry, &ptracer_relations, node) - if (entry->tracee == tracee) { - relation = entry; - break; + rcu_read_lock(); + list_for_each_entry_rcu(relation, &ptracer_relations, node) { + if (relation->tracee == tracee) { + list_replace_rcu(&relation->node, &added->node); + kfree_rcu(relation, rcu); + goto out; } - if (!relation) { - relation = added; - relation->tracee = tracee; - list_add(&relation->node, &ptracer_relations); } - relation->tracer = tracer; - spin_unlock_bh(&ptracer_relations_lock); - if (added != relation) - kfree(added); + list_add_rcu(&added->node, &ptracer_relations); - return rc; +out: + rcu_read_unlock(); + spin_unlock_bh(&ptracer_relations_lock); + return 0; } /** @@ -84,15 +84,18 @@ static int yama_ptracer_add(struct task_struct *tracer, static void yama_ptracer_del(struct task_struct *tracer, struct task_struct *tracee) { - struct ptrace_relation *relation, *safe; + struct ptrace_relation *relation; spin_lock_bh(&ptracer_relations_lock); - list_for_each_entry_safe(relation, safe, &ptracer_relations, node) + rcu_read_lock(); + list_for_each_entry_rcu(relation, &ptracer_relations, node) { if (relation->tracee == tracee || (tracer && relation->tracer == tracer)) { - list_del(&relation->node); - kfree(relation); + list_del_rcu(&relation->node); + kfree_rcu(relation, rcu); } + } + rcu_read_unlock(); spin_unlock_bh(&ptracer_relations_lock); } @@ -217,11 +220,10 @@ static int ptracer_exception_found(struct task_struct *tracer, struct task_struct *parent = NULL; bool found = false; - spin_lock_bh(&ptracer_relations_lock); rcu_read_lock(); if (!thread_group_leader(tracee)) tracee = rcu_dereference(tracee->group_leader); - list_for_each_entry(relation, &ptracer_relations, node) + list_for_each_entry_rcu(relation, &ptracer_relations, node) if (relation->tracee == tracee) { parent = relation->tracer; found = true; @@ -231,7 +233,6 @@ static int ptracer_exception_found(struct task_struct *tracer, if (found && (parent == NULL || task_is_descendant(parent, tracer))) rc = 1; rcu_read_unlock(); - spin_unlock_bh(&ptracer_relations_lock); return rc; } |