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| author | Aristeu Rozanski <aris@redhat.com> | 2012-11-06 07:25:04 -0800 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2012-11-06 07:25:20 -0800 |
| commit | 64e104771351d365e51e588a0e9a656ae6ed2f50 (patch) | |
| tree | e5078e0ba32729735846aa465c1f53f5d98c11ac /security | |
| parent | 3d70f8c617a436c7146ecb81df2265b4626dfe89 (diff) | |
| download | linux-64e104771351d365e51e588a0e9a656ae6ed2f50.tar.gz linux-64e104771351d365e51e588a0e9a656ae6ed2f50.tar.bz2 linux-64e104771351d365e51e588a0e9a656ae6ed2f50.zip | |
device_cgroup: fix unchecked cgroup parent usage
In 4cef7299b478687 ("device_cgroup: add proper checking when changing
default behavior") the cgroup parent usage is unchecked. root will not
have a parent and trying to use device.{allow,deny} will cause problems.
For some reason my stressing scripts didn't test the root directory so I
didn't catch it on my regular tests.
Signed-off-by: Aristeu Rozanski <aris@redhat.com>
Cc: Li Zefan <lizefan@huawei.com>
Cc: James Morris <jmorris@namei.org>
Cc: Pavel Emelyanov <xemul@openvz.org>
Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'security')
| -rw-r--r-- | security/device_cgroup.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/security/device_cgroup.c b/security/device_cgroup.c index 842c254396db..96d87eab1660 100644 --- a/security/device_cgroup.c +++ b/security/device_cgroup.c @@ -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); |