Please pull from the following branch to receive fixes for v3.7-rc5.
It contains two fix patches for device_cgroup. One fixes a regression
introduced earlier in 3.7 cycle where device_cgroup could try to
dereference the NULL parent of the root cgroup. The other one is RCU
usage fix.
git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup.git for-3.7-fixes
Thanks.
---
Aristeu Rozanski (1):
device_cgroup: fix unchecked cgroup parent usage
Tejun Heo (1):
device_cgroup: fix RCU usage
security/device_cgroup.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)
diff --git a/security/device_cgroup.c b/security/device_cgroup.c
index 842c254..b08d20c 100644
--- a/security/device_cgroup.c
+++ b/security/device_cgroup.c
@@ -164,8 +164,8 @@ static void dev_exception_clean(struct dev_cgroup
*dev_cgroup)
struct dev_exception_item *ex, *tmp;
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);
}
}
@@ -298,7 +298,7 @@ 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) {
+ 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 +352,8 @@ 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 +378,14 @@ 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 +396,14 @@ 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);
--
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