diff options
Diffstat (limited to 'security/device_cgroup.c')
| -rw-r--r-- | security/device_cgroup.c | 38 |
1 files changed, 29 insertions, 9 deletions
diff --git a/security/device_cgroup.c b/security/device_cgroup.c index 842c254396db..19ecc8de9e6b 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -82,6 +82,8 @@ static int dev_exceptions_copy(struct list_head *dest, struct list_head *orig) { struct dev_exception_item *ex, *tmp, *new; + lockdep_assert_held(&devcgroup_mutex); + list_for_each_entry(ex, orig, list) { new = kmemdup(ex, sizeof(*ex), GFP_KERNEL); if (!new) @@ -107,6 +109,8 @@ static int dev_exception_add(struct dev_cgroup *dev_cgroup, { struct dev_exception_item *excopy, *walk; + lockdep_assert_held(&devcgroup_mutex); + excopy = kmemdup(ex, sizeof(*ex), GFP_KERNEL); if (!excopy) return -ENOMEM; @@ -137,6 +141,8 @@ static void dev_exception_rm(struct dev_cgroup *dev_cgroup, { struct dev_exception_item *walk, *tmp; + lockdep_assert_held(&devcgroup_mutex); + list_for_each_entry_safe(walk, tmp, &dev_cgroup->exceptions, list) { if (walk->type != ex->type) continue; @@ -163,16 +169,18 @@ static void dev_exception_clean(struct dev_cgroup *dev_cgroup) { struct dev_exception_item *ex, *tmp; + lockdep_assert_held(&devcgroup_mutex); + list_for_each_entry_safe(ex, tmp, &dev_cgroup->exceptions, list) { - list_del(&ex->list); - kfree(ex); + list_del_rcu(&ex->list); + kfree_rcu(ex, rcu); } } /* * called from kernel/cgroup.c with cgroup_lock() held. */ -static struct cgroup_subsys_state *devcgroup_create(struct cgroup *cgroup) +static struct cgroup_subsys_state *devcgroup_css_alloc(struct cgroup *cgroup) { struct dev_cgroup *dev_cgroup, *parent_dev_cgroup; struct cgroup *parent_cgroup; @@ -202,7 +210,7 @@ static struct cgroup_subsys_state *devcgroup_create(struct cgroup *cgroup) return &dev_cgroup->css; } -static void devcgroup_destroy(struct cgroup *cgroup) +static void devcgroup_css_free(struct cgroup *cgroup) { struct dev_cgroup *dev_cgroup; @@ -298,7 +306,11 @@ static int may_access(struct dev_cgroup *dev_cgroup, struct dev_exception_item *ex; bool match = false; - list_for_each_entry(ex, &dev_cgroup->exceptions, list) { + rcu_lockdep_assert(rcu_read_lock_held() || + lockdep_is_held(&devcgroup_mutex), + "device_cgroup::may_access() called without proper synchronization"); + + list_for_each_entry_rcu(ex, &dev_cgroup->exceptions, list) { if ((refex->type & DEV_BLOCK) && !(ex->type & DEV_BLOCK)) continue; if ((refex->type & DEV_CHAR) && !(ex->type & DEV_CHAR)) @@ -352,6 +364,8 @@ static int parent_has_perm(struct dev_cgroup *childcg, */ static inline int may_allow_all(struct dev_cgroup *parent) { + if (!parent) + return 1; return parent->behavior == DEVCG_DEFAULT_ALLOW; } @@ -376,11 +390,14 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, int count, rc; struct dev_exception_item ex; struct cgroup *p = devcgroup->css.cgroup; - struct dev_cgroup *parent = cgroup_to_devcgroup(p->parent); + struct dev_cgroup *parent = NULL; if (!capable(CAP_SYS_ADMIN)) return -EPERM; + if (p->parent) + parent = cgroup_to_devcgroup(p->parent); + memset(&ex, 0, sizeof(ex)); b = buffer; @@ -391,11 +408,14 @@ static int devcgroup_update_access(struct dev_cgroup *devcgroup, if (!may_allow_all(parent)) return -EPERM; dev_exception_clean(devcgroup); + devcgroup->behavior = DEVCG_DEFAULT_ALLOW; + if (!parent) + break; + rc = dev_exceptions_copy(&devcgroup->exceptions, &parent->exceptions); if (rc) return rc; - devcgroup->behavior = DEVCG_DEFAULT_ALLOW; break; case DEVCG_DENY: dev_exception_clean(devcgroup); @@ -544,8 +564,8 @@ static struct cftype dev_cgroup_files[] = { struct cgroup_subsys devices_subsys = { .name = "devices", .can_attach = devcgroup_can_attach, - .create = devcgroup_create, - .destroy = devcgroup_destroy, + .css_alloc = devcgroup_css_alloc, + .css_free = devcgroup_css_free, .subsys_id = devices_subsys_id, .base_cftypes = dev_cgroup_files, |