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authorEric W. Biederman <ebiederm@xmission.com>2013-03-24 14:28:27 -0700
committerEric W. Biederman <ebiederm@xmission.com>2013-03-27 07:50:08 -0700
commit87a8ebd637dafc255070f503909a053cf0d98d3f (patch)
tree0bc879f9118c3333c73dfd15223a79e6219f64fd /kernel/user.c
parenta636b702ed1805e988ad3d8ff8b52c060f8b341c (diff)
downloadlinux-87a8ebd637dafc255070f503909a053cf0d98d3f.tar.bz2
userns: Restrict when proc and sysfs can be mounted
Only allow unprivileged mounts of proc and sysfs if they are already mounted when the user namespace is created. proc and sysfs are interesting because they have content that is per namespace, and so fresh mounts are needed when new namespaces are created while at the same time proc and sysfs have content that is shared between every instance. Respect the policy of who may see the shared content of proc and sysfs by only allowing new mounts if there was an existing mount at the time the user namespace was created. In practice there are only two interesting cases: proc and sysfs are mounted at their usual places, proc and sysfs are not mounted at all (some form of mount namespace jail). Cc: stable@vger.kernel.org Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'kernel/user.c')
-rw-r--r--kernel/user.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/user.c b/kernel/user.c
index e81978e8c03b..8e635a18ab52 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -51,6 +51,8 @@ struct user_namespace init_user_ns = {
.owner = GLOBAL_ROOT_UID,
.group = GLOBAL_ROOT_GID,
.proc_inum = PROC_USER_INIT_INO,
+ .may_mount_sysfs = true,
+ .may_mount_proc = true,
};
EXPORT_SYMBOL_GPL(init_user_ns);