path: root/fs/namespace.c
diff options
authorChristian Brauner <>2020-05-05 16:04:30 +0200
committerChristian Brauner <>2020-05-09 13:57:12 +0200
commitf2a8d52e0a4db968c346c4332630a71cba377567 (patch)
treea5f50de02d68b5fd4599b5f12f584cf955edc5cf /fs/namespace.c
parent0e698dfa282211e414076f9dc7e83c1c288314fd (diff)
nsproxy: add struct nsset
Add a simple struct nsset. It holds all necessary pieces to switch to a new set of namespaces without leaving a task in a half-switched state which we will make use of in the next patch. This patch switches the existing setns logic over without causing a change in setns() behavior. This brings setns() closer to how unshare() works(). The prepare_ns() function is responsible to prepare all necessary information. This has two reasons. First it minimizes dependencies between individual namespaces, i.e. all install handler can expect that all fields are properly initialized independent in what order they are called in. Second, this makes the code easier to maintain and easier to follow if it needs to be changed. The prepare_ns() helper will only be switched over to use a flags argument in the next patch. Here it will still use nstype as a simple integer argument which was argued would be clearer. I'm not particularly opinionated about this if it really helps or not. The struct nsset itself already contains the flags field since its name already indicates that it can contain information required by different namespaces. None of this should have functional consequences. Signed-off-by: Christian Brauner <> Reviewed-by: Serge Hallyn <> Cc: Eric W. Biederman <> Cc: Serge Hallyn <> Cc: Jann Horn <> Cc: Michael Kerrisk <> Cc: Aleksa Sarai <> Link:
Diffstat (limited to 'fs/namespace.c')
1 files changed, 6 insertions, 4 deletions
diff --git a/fs/namespace.c b/fs/namespace.c
index a28e4db075ed..62899fad4a04 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -3954,16 +3954,18 @@ static void mntns_put(struct ns_common *ns)
-static int mntns_install(struct nsproxy *nsproxy, struct ns_common *ns)
+static int mntns_install(struct nsset *nsset, struct ns_common *ns)
- struct fs_struct *fs = current->fs;
+ struct nsproxy *nsproxy = nsset->nsproxy;
+ struct fs_struct *fs = nsset->fs;
struct mnt_namespace *mnt_ns = to_mnt_ns(ns), *old_mnt_ns;
+ struct user_namespace *user_ns = nsset->cred->user_ns;
struct path root;
int err;
if (!ns_capable(mnt_ns->user_ns, CAP_SYS_ADMIN) ||
- !ns_capable(current_user_ns(), CAP_SYS_CHROOT) ||
- !ns_capable(current_user_ns(), CAP_SYS_ADMIN))
+ !ns_capable(user_ns, CAP_SYS_CHROOT) ||
+ !ns_capable(user_ns, CAP_SYS_ADMIN))
return -EPERM;
if (is_anon_ns(mnt_ns))