* CGroup Namespaces (v9)
@ 2016-01-04 19:54 serge.hallyn
2016-01-04 19:54 ` [PATCH 1/8] kernfs: Add API to generate relative kernfs path serge.hallyn
` (8 more replies)
0 siblings, 9 replies; 19+ messages in thread
From: serge.hallyn @ 2016-01-04 19:54 UTC (permalink / raw)
To: linux-kernel
Cc: adityakali, tj, linux-api, containers, cgroups, lxc-devel, akpm,
ebiederm, gregkh, lizefan, hannes
Hi,
following is a revised set of the CGroup Namespace patchset which Aditya
Kali has previously sent. The code can also be found in the cgroupns.v9
branch of
https://git.kernel.org/cgit/linux/kernel/git/sergeh/linux-security.git/
To summarize the semantics:
1. CLONE_NEWCGROUP re-uses 0x02000000, which was previously CLONE_STOPPED
2. unsharing a cgroup namespace makes all your current cgroups your new
cgroup root.
3. /proc/pid/cgroup always shows cgroup paths relative to the reader's
cgroup namespce root. A task outside of your cgroup looks like
8:memory:/../../..
4. when a task mounts a cgroupfs, the cgroup which shows up as root depends
on the mounting task's cgroup namespace.
5. setns to a cgroup namespace switches your cgroup namespace but not
your cgroups.
With this, using github.com/hallyn/lxc #2015-11-09/cgns (and
github.com/hallyn/lxcfs #2015-11-10/cgns) we can start a container in a full
proper cgroup namespace, avoiding either cgmanager or lxcfs cgroup bind mounts.
This is completely backward compatible and will be completely invisible
to any existing cgroup users (except for those running inside a cgroup
namespace and looking at /proc/pid/cgroup of tasks outside their
namespace.)
Changes from V8:
1. Incorporate updated documentation from tj.
1. Put lookup_one_len() under inode lock
2. Make cgroup_path non-namespaced, so only calls to cgroup_path_ns() are
namespaced.
3. Make cgroup_path{,_ns} take the needed locks, since external callers cannot
do so.
4. Fix the bisectability problem of to_cg_ns() being defined after use
Changes from V7:
1. Rework kernfs_path_from_node_locked to return the string length
2. Rename and reorder args to kernfs_path_from_node
3. cgroup.c: undo accidental conversoins to inline
4. cgroup.h: move ns declarations to bottom.
5. Rework the documentation to fit the style of the rest of cgroup.txt
Changes from V6:
1. Switch to some WARN_ONs to provide stack traces
2. Rename kernfs_node_distance to kernfs_depth
3. Make sure kernfs_common_ancestor() nodes are from same root
4. Split kernfs changes for cgroup_mount into separate patch
5. Rename kernfs_obtain_root to kernfs_node_dentry
(And more, see patch changelogs)
Changes from V5:
1. To get a root dentry for cgroup namespace mount, walk the path from the
kernfs root dentry.
Changes from V4:
1. Move the FS_USERNS_MOUNT flag to last patch
2. Rebase onto cgroup/for-4.5
3. Don't non-init user namespaces to bind new subsystems when mounting.
4. Address feedback from Tejun (thanks). Specificaly, not addressed:
. kernfs_obtain_root - walking dentry from kernfs root.
(I think that's the only piece)
5. Dropped unused get_task_cgroup fn/patch.
6. Reworked kernfs_path_from_node_locked() to try to simplify the logic.
It now finds a common ancestor, walks from the source to it, then back
up to the target.
Changes from V3:
1. Rebased onto latest cgroup changes. In particular switch to
css_set_lock and ns_common.
2. Support all hierarchies.
Changes from V2:
1. Added documentation in Documentation/cgroups/namespace.txt
2. Fixed a bug that caused crash
3. Incorporated some other suggestions from last patchset:
- removed use of threadgroup_lock() while creating new cgroupns
- use task_lock() instead of rcu_read_lock() while accessing
task->nsproxy
- optimized setns() to own cgroupns
- simplified code around sane-behavior mount option parsing
4. Restored ACKs from Serge Hallyn from v1 on few patches that have
not changed since then.
Changes from V1:
1. No pinning of processes within cgroupns. Tasks can be freely moved
across cgroups even outside of their cgroupns-root. Usual DAC/MAC policies
apply as before.
2. Path in /proc/<pid>/cgroup is now always shown and is relative to
cgroupns-root. So path can contain '/..' strings depending on cgroupns-root
of the reader and cgroup of <pid>.
3. setns() does not require the process to first move under target
cgroupns-root.
Changes form RFC (V0):
1. setns support for cgroupns
2. 'mount -t cgroup cgroup <mntpt>' from inside a cgroupns now
mounts the cgroup hierarcy with cgroupns-root as the filesystem root.
3. writes to cgroup files outside of cgroupns-root are not allowed
4. visibility of /proc/<pid>/cgroup is further restricted by not showing
anything if the <pid> is in a sibling cgroupns and its cgroup falls outside
your cgroupns-root.
^ permalink raw reply [flat|nested] 19+ messages in thread
* [PATCH 1/8] kernfs: Add API to generate relative kernfs path
2016-01-04 19:54 CGroup Namespaces (v9) serge.hallyn
@ 2016-01-04 19:54 ` serge.hallyn
2016-01-04 19:54 ` [PATCH 2/8] sched: new clone flag CLONE_NEWCGROUP for cgroup namespace serge.hallyn
` (7 subsequent siblings)
8 siblings, 0 replies; 19+ messages in thread
From: serge.hallyn @ 2016-01-04 19:54 UTC (permalink / raw)
To: linux-kernel
Cc: adityakali, tj, linux-api, containers, cgroups, lxc-devel, akpm,
ebiederm, gregkh, lizefan, hannes, Serge E. Hallyn
From: Aditya Kali <adityakali@google.com>
The new function kernfs_path_from_node() generates and returns kernfs
path of a given kernfs_node relative to a given parent kernfs_node.
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Changelog 20151125:
- Fully-wing multilinecomments
- Rework kernfs_path_from_node_locked() logic
- Replace BUG_ONs with returning NULL
- Use a const char* for /.. and precalculate its size
Changelog 20151130:
- Update kernfs_path_from_node_locked comment
Changelog 20151208:
- kernfs_node_distance:
* Remove BUG_ON(NULL)s
* Rename kernfs_node_distance to kernfs_depth
- kernfs_common-ancestor:
* Remove useless checks for depth == 0
* Add check to ensure nodes are from same root
- kernfs_path_from_node_locked:
* Remove needless __must_check
* Put p;len on its own decl line.
* Fix wrong WARN_ONCE usage
Changelog 20151209:
- kernfs_path_from_node: change arguments to 'to' and 'from', and
change their order.
Changelog 20151222:
- kernfs_path_from_node{,_locked}: return the string length.
kernfs_path is gpl-exported, so changing their return value seemed
ill-advised, but if noone minds I can update it too.
Changelog 20151223:
- don't allocate memory pr_cont_kernfs_path() under spinlock
---
fs/kernfs/dir.c | 192 ++++++++++++++++++++++++++++++++++++++++--------
include/linux/kernfs.h | 9 ++-
2 files changed, 166 insertions(+), 35 deletions(-)
diff --git a/fs/kernfs/dir.c b/fs/kernfs/dir.c
index 742bf4a..f2b2187 100644
--- a/fs/kernfs/dir.c
+++ b/fs/kernfs/dir.c
@@ -44,28 +44,123 @@ static int kernfs_name_locked(struct kernfs_node *kn, char *buf, size_t buflen)
return strlcpy(buf, kn->parent ? kn->name : "/", buflen);
}
-static char * __must_check kernfs_path_locked(struct kernfs_node *kn, char *buf,
- size_t buflen)
+/* kernfs_node_depth - compute depth from @from to @to */
+static size_t kernfs_depth(struct kernfs_node *from, struct kernfs_node *to)
{
- char *p = buf + buflen;
- int len;
+ size_t depth = 0;
- *--p = '\0';
+ while (to->parent && to != from) {
+ depth++;
+ to = to->parent;
+ }
+ return depth;
+}
- do {
- len = strlen(kn->name);
- if (p - buf < len + 1) {
- buf[0] = '\0';
- p = NULL;
- break;
- }
- p -= len;
- memcpy(p, kn->name, len);
- *--p = '/';
- kn = kn->parent;
- } while (kn && kn->parent);
+static struct kernfs_node *kernfs_common_ancestor(struct kernfs_node *a,
+ struct kernfs_node *b)
+{
+ size_t da, db;
+ struct kernfs_root *ra = kernfs_root(a), *rb = kernfs_root(b);
+
+ if (ra != rb)
+ return NULL;
+
+ da = kernfs_depth(ra->kn, a);
+ db = kernfs_depth(rb->kn, b);
+
+ while (da > db) {
+ a = a->parent;
+ da--;
+ }
+ while (db > da) {
+ b = b->parent;
+ db--;
+ }
+
+ /* worst case b and a will be the same at root */
+ while (b != a) {
+ b = b->parent;
+ a = a->parent;
+ }
+
+ return a;
+}
+
+/**
+ * kernfs_path_from_node_locked - find a pseudo-absolute path to @kn_to,
+ * where kn_from is treated as root of the path.
+ * @kn_from: kernfs node which should be treated as root for the path
+ * @kn_to: kernfs node to which path is needed
+ * @buf: buffer to copy the path into
+ * @buflen: size of @buf
+ *
+ * We need to handle couple of scenarios here:
+ * [1] when @kn_from is an ancestor of @kn_to at some level
+ * kn_from: /n1/n2/n3
+ * kn_to: /n1/n2/n3/n4/n5
+ * result: /n4/n5
+ *
+ * [2] when @kn_from is on a different hierarchy and we need to find common
+ * ancestor between @kn_from and @kn_to.
+ * kn_from: /n1/n2/n3/n4
+ * kn_to: /n1/n2/n5
+ * result: /../../n5
+ * OR
+ * kn_from: /n1/n2/n3/n4/n5 [depth=5]
+ * kn_to: /n1/n2/n3 [depth=3]
+ * result: /../..
+ *
+ * return value: length of the string. If greater than buflen,
+ * then contents of buf are undefined. On error, -1 is returned.
+ */
+static int
+kernfs_path_from_node_locked(struct kernfs_node *kn_to,
+ struct kernfs_node *kn_from, char *buf,
+ size_t buflen)
+{
+ struct kernfs_node *kn, *common;
+ const char parent_str[] = "/..";
+ size_t depth_from, depth_to, len = 0, nlen = 0;
+ char *p;
+ int i;
+
+ if (!kn_from)
+ kn_from = kernfs_root(kn_to)->kn;
+
+ if (kn_from == kn_to)
+ return strlcpy(buf, "/", buflen);
+
+ common = kernfs_common_ancestor(kn_from, kn_to);
+ if (WARN_ON(!common))
+ return -1;
+
+ depth_to = kernfs_depth(common, kn_to);
+ depth_from = kernfs_depth(common, kn_from);
+
+ if (buf)
+ buf[0] = '\0';
- return p;
+ for (i = 0; i < depth_from; i++)
+ len += strlcpy(buf + len, parent_str,
+ len < buflen ? buflen - len : 0);
+
+ /* Calculate how many bytes we need for the rest */
+ for (kn = kn_to; kn != common; kn = kn->parent)
+ nlen += strlen(kn->name) + 1;
+
+ if (len + nlen >= buflen)
+ return len + nlen;
+
+ p = buf + len + nlen;
+ *p = '\0';
+ for (kn = kn_to; kn != common; kn = kn->parent) {
+ nlen = strlen(kn->name);
+ p -= nlen;
+ memcpy(p, kn->name, nlen);
+ *(--p) = '/';
+ }
+
+ return len + nlen;
}
/**
@@ -115,6 +210,34 @@ size_t kernfs_path_len(struct kernfs_node *kn)
}
/**
+ * kernfs_path_from_node - build path of node @to relative to @from.
+ * @from: parent kernfs_node relative to which we need to build the path
+ * @to: kernfs_node of interest
+ * @buf: buffer to copy @to's path into
+ * @buflen: size of @buf
+ *
+ * Builds @to's path relative to @from in @buf. @from and @to must
+ * be on the same kernfs-root. If @from is not parent of @to, then a relative
+ * path (which includes '..'s) as needed to reach from @from to @to is
+ * returned.
+ *
+ * If @buf isn't long enough, the return value will be greater than @buflen
+ * and @buf contents are undefined.
+ */
+int kernfs_path_from_node(struct kernfs_node *to, struct kernfs_node *from,
+ char *buf, size_t buflen)
+{
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(&kernfs_rename_lock, flags);
+ ret = kernfs_path_from_node_locked(to, from, buf, buflen);
+ spin_unlock_irqrestore(&kernfs_rename_lock, flags);
+ return ret;
+}
+EXPORT_SYMBOL_GPL(kernfs_path_from_node);
+
+/**
* kernfs_path - build full path of a given node
* @kn: kernfs_node of interest
* @buf: buffer to copy @kn's name into
@@ -127,13 +250,12 @@ size_t kernfs_path_len(struct kernfs_node *kn)
*/
char *kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen)
{
- unsigned long flags;
- char *p;
+ int ret;
- spin_lock_irqsave(&kernfs_rename_lock, flags);
- p = kernfs_path_locked(kn, buf, buflen);
- spin_unlock_irqrestore(&kernfs_rename_lock, flags);
- return p;
+ ret = kernfs_path_from_node(kn, NULL, buf, buflen);
+ if (ret < 0 || ret >= buflen)
+ return NULL;
+ return buf;
}
EXPORT_SYMBOL_GPL(kernfs_path);
@@ -164,17 +286,25 @@ void pr_cont_kernfs_name(struct kernfs_node *kn)
void pr_cont_kernfs_path(struct kernfs_node *kn)
{
unsigned long flags;
- char *p;
+ int sz;
spin_lock_irqsave(&kernfs_rename_lock, flags);
- p = kernfs_path_locked(kn, kernfs_pr_cont_buf,
- sizeof(kernfs_pr_cont_buf));
- if (p)
- pr_cont("%s", p);
- else
- pr_cont("<name too long>");
+ sz = kernfs_path_from_node_locked(kn, NULL, kernfs_pr_cont_buf,
+ sizeof(kernfs_pr_cont_buf));
+ if (sz < 0) {
+ pr_cont("(error)");
+ goto out;
+ }
+
+ if (sz >= sizeof(kernfs_pr_cont_buf)) {
+ pr_cont("(name too long)");
+ goto out;
+ }
+
+ pr_cont("%s", kernfs_pr_cont_buf);
+out:
spin_unlock_irqrestore(&kernfs_rename_lock, flags);
}
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index af51df3..716bfde 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -267,8 +267,9 @@ static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen);
size_t kernfs_path_len(struct kernfs_node *kn);
-char * __must_check kernfs_path(struct kernfs_node *kn, char *buf,
- size_t buflen);
+int kernfs_path_from_node(struct kernfs_node *root_kn, struct kernfs_node *kn,
+ char *buf, size_t buflen);
+char *kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen);
void pr_cont_kernfs_name(struct kernfs_node *kn);
void pr_cont_kernfs_path(struct kernfs_node *kn);
struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn);
@@ -338,8 +339,8 @@ static inline int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
static inline size_t kernfs_path_len(struct kernfs_node *kn)
{ return 0; }
-static inline char * __must_check kernfs_path(struct kernfs_node *kn, char *buf,
- size_t buflen)
+static inline char *kernfs_path(struct kernfs_node *kn, char *buf,
+ size_t buflen)
{ return NULL; }
static inline void pr_cont_kernfs_name(struct kernfs_node *kn) { }
--
1.7.9.5
^ permalink raw reply related [flat|nested] 19+ messages in thread
* [PATCH 2/8] sched: new clone flag CLONE_NEWCGROUP for cgroup namespace
2016-01-04 19:54 CGroup Namespaces (v9) serge.hallyn
2016-01-04 19:54 ` [PATCH 1/8] kernfs: Add API to generate relative kernfs path serge.hallyn
@ 2016-01-04 19:54 ` serge.hallyn
2016-01-04 19:54 ` [PATCH 3/8] cgroup: introduce cgroup namespaces serge.hallyn
` (6 subsequent siblings)
8 siblings, 0 replies; 19+ messages in thread
From: serge.hallyn @ 2016-01-04 19:54 UTC (permalink / raw)
To: linux-kernel
Cc: adityakali, tj, linux-api, containers, cgroups, lxc-devel, akpm,
ebiederm, gregkh, lizefan, hannes, Serge Hallyn
From: Aditya Kali <adityakali@google.com>
CLONE_NEWCGROUP will be used to create new cgroup namespace.
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
---
include/uapi/linux/sched.h | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/include/uapi/linux/sched.h b/include/uapi/linux/sched.h
index cc89dde..5f0fe01 100644
--- a/include/uapi/linux/sched.h
+++ b/include/uapi/linux/sched.h
@@ -21,8 +21,7 @@
#define CLONE_DETACHED 0x00400000 /* Unused, ignored */
#define CLONE_UNTRACED 0x00800000 /* set if the tracing process can't force CLONE_PTRACE on this clone */
#define CLONE_CHILD_SETTID 0x01000000 /* set the TID in the child */
-/* 0x02000000 was previously the unused CLONE_STOPPED (Start in stopped state)
- and is now available for re-use. */
+#define CLONE_NEWCGROUP 0x02000000 /* New cgroup namespace */
#define CLONE_NEWUTS 0x04000000 /* New utsname namespace */
#define CLONE_NEWIPC 0x08000000 /* New ipc namespace */
#define CLONE_NEWUSER 0x10000000 /* New user namespace */
--
1.7.9.5
^ permalink raw reply related [flat|nested] 19+ messages in thread
* [PATCH 3/8] cgroup: introduce cgroup namespaces
2016-01-04 19:54 CGroup Namespaces (v9) serge.hallyn
2016-01-04 19:54 ` [PATCH 1/8] kernfs: Add API to generate relative kernfs path serge.hallyn
2016-01-04 19:54 ` [PATCH 2/8] sched: new clone flag CLONE_NEWCGROUP for cgroup namespace serge.hallyn
@ 2016-01-04 19:54 ` serge.hallyn
2016-01-04 20:20 ` Serge E. Hallyn
2016-01-05 2:07 ` [PATCH 3/8 v2] " Serge E. Hallyn
2016-01-04 19:54 ` [PATCH 4/8] cgroup: cgroup namespace setns support serge.hallyn
` (5 subsequent siblings)
8 siblings, 2 replies; 19+ messages in thread
From: serge.hallyn @ 2016-01-04 19:54 UTC (permalink / raw)
To: linux-kernel
Cc: adityakali, tj, linux-api, containers, cgroups, lxc-devel, akpm,
ebiederm, gregkh, lizefan, hannes, Serge Hallyn
From: Aditya Kali <adityakali@google.com>
Introduce the ability to create new cgroup namespace. The newly created
cgroup namespace remembers the cgroup of the process at the point
of creation of the cgroup namespace (referred as cgroupns-root).
The main purpose of cgroup namespace is to virtualize the contents
of /proc/self/cgroup file. Processes inside a cgroup namespace
are only able to see paths relative to their namespace root
(unless they are moved outside of their cgroupns-root, at which point
they will see a relative path from their cgroupns-root).
For a correctly setup container this enables container-tools
(like libcontainer, lxc, lmctfy, etc.) to create completely virtualized
containers without leaking system level cgroup hierarchy to the task.
This patch only implements the 'unshare' part of the cgroupns.
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
---
Changelog: 2015-11-24
- move cgroup_namespace.c into cgroup.c (and .h)
- reformatting
- make get_cgroup_ns return void
- rename ns->root_cgrps to root_cset.
Changelog: 2015-12-08
- Move init_cgroup_ns to other variable declarations
- Remove accidental conversion of put-css_set to inline
- Drop BUG_ON(NULL)
- Remove unneeded pre declaration of struct cgroupns_operations.
- cgroup.h: collect common ns declerations
Changelog: 2015-12-09
- cgroup.h: move ns declarations to bottom
- cgroup.c: undo all accidental conversions to inline
Changelog: 2015-12-22
- update for new kernfs_path_from_node() return value. Since
cgroup_path was already gpl-exported, I abstained from updating
its return value.
Changelog: 2015-12-23
- cgroup_path(): use init_cgroup_ns when in interupt context.
Changelog: 2015-01-02
- move to_cg_ns definition forward in patch series
- cgroup_release_agent: grab css_set_lock around cgroup_path()
- leave cgroup_path non-namespaced, use cgroup_path_ns when
namespaced path is desired.
---
fs/proc/namespaces.c | 3 +
include/linux/cgroup.h | 56 +++++++++++++--
include/linux/nsproxy.h | 2 +
include/linux/proc_ns.h | 4 ++
kernel/cgroup.c | 177 ++++++++++++++++++++++++++++++++++++++++++++++-
kernel/cpuset.c | 3 +-
kernel/fork.c | 2 +-
kernel/nsproxy.c | 21 +++++-
kernel/sched/debug.c | 3 +-
9 files changed, 257 insertions(+), 14 deletions(-)
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index f6e8354..bd61075 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -28,6 +28,9 @@ static const struct proc_ns_operations *ns_entries[] = {
&userns_operations,
#endif
&mntns_operations,
+#ifdef CONFIG_CGROUPS
+ &cgroupns_operations,
+#endif
};
static const char *proc_ns_follow_link(struct dentry *dentry, void **cookie)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 9d70b48..149ae0a 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -17,6 +17,11 @@
#include <linux/seq_file.h>
#include <linux/kernfs.h>
#include <linux/jump_label.h>
+#include <linux/nsproxy.h>
+#include <linux/types.h>
+#include <linux/ns_common.h>
+#include <linux/nsproxy.h>
+#include <linux/user_namespace.h>
#include <linux/cgroup-defs.h>
@@ -532,12 +537,6 @@ static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen)
return kernfs_name(cgrp->kn, buf, buflen);
}
-static inline char * __must_check cgroup_path(struct cgroup *cgrp, char *buf,
- size_t buflen)
-{
- return kernfs_path(cgrp->kn, buf, buflen);
-}
-
static inline void pr_cont_cgroup_name(struct cgroup *cgrp)
{
pr_cont_kernfs_name(cgrp->kn);
@@ -570,4 +569,49 @@ static inline int cgroup_init(void) { return 0; }
#endif /* !CONFIG_CGROUPS */
+struct cgroup_namespace {
+ atomic_t count;
+ struct ns_common ns;
+ struct user_namespace *user_ns;
+ struct css_set *root_cset;
+};
+
+extern struct cgroup_namespace init_cgroup_ns;
+
+#ifdef CONFIG_CGROUPS
+
+void free_cgroup_ns(struct cgroup_namespace *ns);
+
+struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns);
+
+char *cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns);
+char *cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen);
+
+#else /* !CONFIG_CGROUPS */
+
+static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
+static inline struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns)
+{
+ return old_ns;
+}
+
+#endif /* !CONFIG_CGROUPS */
+
+static inline void get_cgroup_ns(struct cgroup_namespace *ns)
+{
+ if (ns)
+ atomic_inc(&ns->count);
+}
+
+static inline void put_cgroup_ns(struct cgroup_namespace *ns)
+{
+ if (ns && atomic_dec_and_test(&ns->count))
+ free_cgroup_ns(ns);
+}
+
#endif /* _LINUX_CGROUP_H */
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 35fa08f..ac0d65b 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -8,6 +8,7 @@ struct mnt_namespace;
struct uts_namespace;
struct ipc_namespace;
struct pid_namespace;
+struct cgroup_namespace;
struct fs_struct;
/*
@@ -33,6 +34,7 @@ struct nsproxy {
struct mnt_namespace *mnt_ns;
struct pid_namespace *pid_ns_for_children;
struct net *net_ns;
+ struct cgroup_namespace *cgroup_ns;
};
extern struct nsproxy init_nsproxy;
diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h
index 42dfc61..de0e771 100644
--- a/include/linux/proc_ns.h
+++ b/include/linux/proc_ns.h
@@ -9,6 +9,8 @@
struct pid_namespace;
struct nsproxy;
struct path;
+struct task_struct;
+struct inode;
struct proc_ns_operations {
const char *name;
@@ -24,6 +26,7 @@ extern const struct proc_ns_operations ipcns_operations;
extern const struct proc_ns_operations pidns_operations;
extern const struct proc_ns_operations userns_operations;
extern const struct proc_ns_operations mntns_operations;
+extern const struct proc_ns_operations cgroupns_operations;
/*
* We always define these enumerators
@@ -34,6 +37,7 @@ enum {
PROC_UTS_INIT_INO = 0xEFFFFFFEU,
PROC_USER_INIT_INO = 0xEFFFFFFDU,
PROC_PID_INIT_INO = 0xEFFFFFFCU,
+ PROC_CGROUP_INIT_INO = 0xEFFFFFFBU,
};
#ifdef CONFIG_PROC_FS
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 6b33631..60270b1 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -57,6 +57,9 @@
#include <linux/vmalloc.h> /* TODO: replace with more sophisticated array */
#include <linux/kthread.h>
#include <linux/delay.h>
+#include <linux/proc_ns.h>
+#include <linux/nsproxy.h>
+#include <linux/proc_ns.h>
#include <linux/atomic.h>
@@ -208,6 +211,15 @@ static unsigned long have_fork_callback __read_mostly;
static unsigned long have_exit_callback __read_mostly;
static unsigned long have_free_callback __read_mostly;
+/* Cgroup namespace for init task */
+struct cgroup_namespace init_cgroup_ns = {
+ .count = { .counter = 2, },
+ .user_ns = &init_user_ns,
+ .ns.ops = &cgroupns_operations,
+ .ns.inum = PROC_CGROUP_INIT_INO,
+ .root_cset = &init_css_set,
+};
+
/* Ditto for the can_fork callback. */
static unsigned long have_canfork_callback __read_mostly;
@@ -2166,6 +2178,43 @@ static struct file_system_type cgroup2_fs_type = {
.kill_sb = cgroup_kill_sb,
};
+char *
+cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns)
+{
+ int ret;
+ struct cgroup *root = cset_cgroup_from_root(ns->root_cset, cgrp->root);
+
+ ret = kernfs_path_from_node(cgrp->kn, root->kn, buf, buflen);
+ if (ret < 0 || ret >= buflen)
+ return NULL;
+ return buf;
+}
+
+char *cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns)
+{
+ char *ret;
+
+ mutex_lock(&cgroup_mutex);
+ spin_lock_bh(&css_set_lock);
+
+ ret = cgroup_path_ns_locked(cgrp, buf, buflen, ns);
+
+ spin_unlock_bh(&css_set_lock);
+ mutex_unlock(&cgroup_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(cgroup_path_ns);
+
+char *cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen)
+{
+ return cgroup_path_ns(cgrp, buf, buflen, &init_cgroup_ns);
+}
+
+EXPORT_SYMBOL_GPL(cgroup_path);
+
/**
* task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
* @task: target task
@@ -2193,7 +2242,8 @@ char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
if (root) {
cgrp = task_cgroup_from_root(task, root);
- path = cgroup_path(cgrp, buf, buflen);
+ path = cgroup_path_ns_locked(cgrp, buf, buflen,
+ &init_cgroup_ns);
} else {
/* if no hierarchy exists, everyone is in "/" */
if (strlcpy(buf, "/", buflen) < buflen)
@@ -5272,6 +5322,8 @@ int __init cgroup_init(void)
BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));
+ get_user_ns(init_cgroup_ns.user_ns);
+
mutex_lock(&cgroup_mutex);
/* Add init_css_set to the hash table */
@@ -5409,7 +5461,8 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
* " (deleted)" is appended to the cgroup path.
*/
if (cgroup_on_dfl(cgrp) || !(tsk->flags & PF_EXITING)) {
- path = cgroup_path(cgrp, buf, PATH_MAX);
+ path = cgroup_path_ns_locked(cgrp, buf, PATH_MAX,
+ current->nsproxy->cgroup_ns);
if (!path) {
retval = -ENAMETOOLONG;
goto out_unlock;
@@ -5691,7 +5744,10 @@ static void cgroup_release_agent(struct work_struct *work)
if (!pathbuf || !agentbuf)
goto out;
- path = cgroup_path(cgrp, pathbuf, PATH_MAX);
+ spin_lock_bh(&css_set_lock);
+ path = cgroup_path_ns_locked(cgrp, pathbuf, PATH_MAX,
+ &init_cgroup_ns);
+ spin_unlock_bh(&css_set_lock);
if (!path)
goto out;
@@ -5822,6 +5878,121 @@ struct cgroup *cgroup_get_from_path(const char *path)
}
EXPORT_SYMBOL_GPL(cgroup_get_from_path);
+/* cgroup namespaces */
+
+static struct cgroup_namespace *alloc_cgroup_ns(void)
+{
+ struct cgroup_namespace *new_ns;
+ int ret;
+
+ new_ns = kzalloc(sizeof(struct cgroup_namespace), GFP_KERNEL);
+ if (!new_ns)
+ return ERR_PTR(-ENOMEM);
+ ret = ns_alloc_inum(&new_ns->ns);
+ if (ret) {
+ kfree(new_ns);
+ return ERR_PTR(ret);
+ }
+ atomic_set(&new_ns->count, 1);
+ new_ns->ns.ops = &cgroupns_operations;
+ return new_ns;
+}
+
+void free_cgroup_ns(struct cgroup_namespace *ns)
+{
+ put_css_set(ns->root_cset);
+ put_user_ns(ns->user_ns);
+ ns_free_inum(&ns->ns);
+ kfree(ns);
+}
+EXPORT_SYMBOL(free_cgroup_ns);
+
+struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns)
+{
+ struct cgroup_namespace *new_ns = NULL;
+ struct css_set *cset = NULL;
+ int err;
+
+ BUG_ON(!old_ns);
+
+ if (!(flags & CLONE_NEWCGROUP)) {
+ get_cgroup_ns(old_ns);
+ return old_ns;
+ }
+
+ /* Allow only sysadmin to create cgroup namespace. */
+ err = -EPERM;
+ if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+ goto err_out;
+
+ cset = task_css_set(current);
+ get_css_set(cset);
+
+ err = -ENOMEM;
+ new_ns = alloc_cgroup_ns();
+ if (!new_ns)
+ goto err_out;
+
+ new_ns->user_ns = get_user_ns(user_ns);
+ new_ns->root_cset = cset;
+
+ return new_ns;
+
+err_out:
+ if (cset)
+ put_css_set(cset);
+ kfree(new_ns);
+ return ERR_PTR(err);
+}
+
+static inline struct cgroup_namespace *to_cg_ns(struct ns_common *ns)
+{
+ return container_of(ns, struct cgroup_namespace, ns);
+}
+
+static int cgroupns_install(struct nsproxy *nsproxy, void *ns)
+{
+ pr_info("setns not supported for cgroup namespace");
+ return -EINVAL;
+}
+
+static struct ns_common *cgroupns_get(struct task_struct *task)
+{
+ struct cgroup_namespace *ns = NULL;
+ struct nsproxy *nsproxy;
+
+ task_lock(task);
+ nsproxy = task->nsproxy;
+ if (nsproxy) {
+ ns = nsproxy->cgroup_ns;
+ get_cgroup_ns(ns);
+ }
+ task_unlock(task);
+
+ return ns ? &ns->ns : NULL;
+}
+
+static void cgroupns_put(struct ns_common *ns)
+{
+ put_cgroup_ns(to_cg_ns(ns));
+}
+
+const struct proc_ns_operations cgroupns_operations = {
+ .name = "cgroup",
+ .type = CLONE_NEWCGROUP,
+ .get = cgroupns_get,
+ .put = cgroupns_put,
+ .install = cgroupns_install,
+};
+
+static __init int cgroup_namespaces_init(void)
+{
+ return 0;
+}
+subsys_initcall(cgroup_namespaces_init);
+
#ifdef CONFIG_CGROUP_DEBUG
static struct cgroup_subsys_state *
debug_css_alloc(struct cgroup_subsys_state *parent_css)
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 3e945fc..37c8eb0 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2689,7 +2689,8 @@ int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
retval = -ENAMETOOLONG;
rcu_read_lock();
css = task_css(tsk, cpuset_cgrp_id);
- p = cgroup_path(css->cgroup, buf, PATH_MAX);
+ p = cgroup_path_ns(css->cgroup, buf, PATH_MAX,
+ current->nsproxy->cgroup_ns);
rcu_read_unlock();
if (!p)
goto out_free;
diff --git a/kernel/fork.c b/kernel/fork.c
index ba7d1c0..7982fee 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1880,7 +1880,7 @@ static int check_unshare_flags(unsigned long unshare_flags)
if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET|
- CLONE_NEWUSER|CLONE_NEWPID))
+ CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP))
return -EINVAL;
/*
* Not implemented, but pretend it works if there is nothing
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 49746c8..64fe865 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -25,6 +25,7 @@
#include <linux/proc_ns.h>
#include <linux/file.h>
#include <linux/syscalls.h>
+#include <linux/cgroup.h>
static struct kmem_cache *nsproxy_cachep;
@@ -39,6 +40,9 @@ struct nsproxy init_nsproxy = {
#ifdef CONFIG_NET
.net_ns = &init_net,
#endif
+#ifdef CONFIG_CGROUPS
+ .cgroup_ns = &init_cgroup_ns,
+#endif
};
static inline struct nsproxy *create_nsproxy(void)
@@ -92,6 +96,13 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
goto out_pid;
}
+ new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns,
+ tsk->nsproxy->cgroup_ns);
+ if (IS_ERR(new_nsp->cgroup_ns)) {
+ err = PTR_ERR(new_nsp->cgroup_ns);
+ goto out_cgroup;
+ }
+
new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
if (IS_ERR(new_nsp->net_ns)) {
err = PTR_ERR(new_nsp->net_ns);
@@ -101,6 +112,9 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
return new_nsp;
out_net:
+ if (new_nsp->cgroup_ns)
+ put_cgroup_ns(new_nsp->cgroup_ns);
+out_cgroup:
if (new_nsp->pid_ns_for_children)
put_pid_ns(new_nsp->pid_ns_for_children);
out_pid:
@@ -128,7 +142,8 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
struct nsproxy *new_ns;
if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWPID | CLONE_NEWNET)))) {
+ CLONE_NEWPID | CLONE_NEWNET |
+ CLONE_NEWCGROUP)))) {
get_nsproxy(old_ns);
return 0;
}
@@ -165,6 +180,8 @@ void free_nsproxy(struct nsproxy *ns)
put_ipc_ns(ns->ipc_ns);
if (ns->pid_ns_for_children)
put_pid_ns(ns->pid_ns_for_children);
+ if (ns->cgroup_ns)
+ put_cgroup_ns(ns->cgroup_ns);
put_net(ns->net_ns);
kmem_cache_free(nsproxy_cachep, ns);
}
@@ -180,7 +197,7 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
int err = 0;
if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWNET | CLONE_NEWPID)))
+ CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP)))
return 0;
user_ns = new_cred ? new_cred->user_ns : current_user_ns();
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 6415117..4c28523 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -104,7 +104,8 @@ static char *task_group_path(struct task_group *tg)
if (autogroup_path(tg, group_path, PATH_MAX))
return group_path;
- return cgroup_path(tg->css.cgroup, group_path, PATH_MAX);
+ return cgroup_path_ns(tg->css.cgroup, group_path, PATH_MAX,
+ current->nsproxy->cgroup_ns);
}
#endif
--
1.7.9.5
^ permalink raw reply related [flat|nested] 19+ messages in thread
* [PATCH 4/8] cgroup: cgroup namespace setns support
2016-01-04 19:54 CGroup Namespaces (v9) serge.hallyn
` (2 preceding siblings ...)
2016-01-04 19:54 ` [PATCH 3/8] cgroup: introduce cgroup namespaces serge.hallyn
@ 2016-01-04 19:54 ` serge.hallyn
2016-01-04 19:54 ` [PATCH 5/8] kernfs: define kernfs_node_dentry serge.hallyn
` (4 subsequent siblings)
8 siblings, 0 replies; 19+ messages in thread
From: serge.hallyn @ 2016-01-04 19:54 UTC (permalink / raw)
To: linux-kernel
Cc: adityakali, tj, linux-api, containers, cgroups, lxc-devel, akpm,
ebiederm, gregkh, lizefan, hannes, Serge E. Hallyn
From: Aditya Kali <adityakali@google.com>
setns on a cgroup namespace is allowed only if
task has CAP_SYS_ADMIN in its current user-namespace and
over the user-namespace associated with target cgroupns.
No implicit cgroup changes happen with attaching to another
cgroupns. It is expected that the somone moves the attaching
process under the target cgroupns-root.
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
---
kernel/cgroup.c | 19 ++++++++++++++++---
1 file changed, 16 insertions(+), 3 deletions(-)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 60270b1..2bb58a1 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -5952,10 +5952,23 @@ static inline struct cgroup_namespace *to_cg_ns(struct ns_common *ns)
return container_of(ns, struct cgroup_namespace, ns);
}
-static int cgroupns_install(struct nsproxy *nsproxy, void *ns)
+static int cgroupns_install(struct nsproxy *nsproxy, struct ns_common *ns)
{
- pr_info("setns not supported for cgroup namespace");
- return -EINVAL;
+ struct cgroup_namespace *cgroup_ns = to_cg_ns(ns);
+
+ if (!ns_capable(current_user_ns(), CAP_SYS_ADMIN) ||
+ !ns_capable(cgroup_ns->user_ns, CAP_SYS_ADMIN))
+ return -EPERM;
+
+ /* Don't need to do anything if we are attaching to our own cgroupns. */
+ if (cgroup_ns == nsproxy->cgroup_ns)
+ return 0;
+
+ get_cgroup_ns(cgroup_ns);
+ put_cgroup_ns(nsproxy->cgroup_ns);
+ nsproxy->cgroup_ns = cgroup_ns;
+
+ return 0;
}
static struct ns_common *cgroupns_get(struct task_struct *task)
--
1.7.9.5
^ permalink raw reply related [flat|nested] 19+ messages in thread
* [PATCH 5/8] kernfs: define kernfs_node_dentry
2016-01-04 19:54 CGroup Namespaces (v9) serge.hallyn
` (3 preceding siblings ...)
2016-01-04 19:54 ` [PATCH 4/8] cgroup: cgroup namespace setns support serge.hallyn
@ 2016-01-04 19:54 ` serge.hallyn
2016-01-04 19:54 ` [PATCH 6/8] cgroup: mount cgroupns-root when inside non-init cgroupns serge.hallyn
` (3 subsequent siblings)
8 siblings, 0 replies; 19+ messages in thread
From: serge.hallyn @ 2016-01-04 19:54 UTC (permalink / raw)
To: linux-kernel
Cc: adityakali, tj, linux-api, containers, cgroups, lxc-devel, akpm,
ebiederm, gregkh, lizefan, hannes, Serge E. Hallyn
From: Aditya Kali <adityakali@google.com>
Add a new kernfs api is added to lookup the dentry for a particular
kernfs path.
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
Changelog:
20151116 - Don't allow user namespaces to bind new subsystems
20151118 - postpone the FS_USERNS_MOUNT flag until the
last patch, until we can convince ourselves it
is safe.
20151207 - Switch to walking up the kernfs path from kn root.
20151208 - Split out the kernfs change
- Style changes
- Switch from pr_crit to WARN_ON
- Reorder arguments to kernfs_obtain_root
- rename kernfs_obtain_root to kernfs_node_dentry
---
fs/kernfs/mount.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/kernfs.h | 2 ++
2 files changed, 69 insertions(+)
diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c
index 8eaf417..7224296 100644
--- a/fs/kernfs/mount.c
+++ b/fs/kernfs/mount.c
@@ -14,6 +14,7 @@
#include <linux/magic.h>
#include <linux/slab.h>
#include <linux/pagemap.h>
+#include <linux/namei.h>
#include "kernfs-internal.h"
@@ -62,6 +63,72 @@ struct kernfs_root *kernfs_root_from_sb(struct super_block *sb)
return NULL;
}
+/*
+ * find the next ancestor in the path down to @child, where @parent was the
+ * ancestor whose descendant we want to find.
+ *
+ * Say the path is /a/b/c/d. @child is d, @parent is NULL. We return the root
+ * node. If @parent is b, then we return the node for c.
+ * Passing in d as @parent is not ok.
+ */
+static struct kernfs_node *
+find_next_ancestor(struct kernfs_node *child, struct kernfs_node *parent)
+{
+ if (child == parent) {
+ pr_crit_once("BUG in find_next_ancestor: called with parent == child");
+ return NULL;
+ }
+
+ while (child->parent != parent) {
+ if (!child->parent)
+ return NULL;
+ child = child->parent;
+ }
+
+ return child;
+}
+
+/**
+ * kernfs_node_dentry - get a dentry for the given kernfs_node
+ * @kn: kernfs_node for which a dentry is needed
+ * @sb: the kernfs super_block
+ */
+struct dentry *kernfs_node_dentry(struct kernfs_node *kn,
+ struct super_block *sb)
+{
+ struct dentry *dentry;
+ struct kernfs_node *knparent = NULL;
+
+ BUG_ON(sb->s_op != &kernfs_sops);
+
+ dentry = dget(sb->s_root);
+
+ /* Check if this is the root kernfs_node */
+ if (!kn->parent)
+ return dentry;
+
+ knparent = find_next_ancestor(kn, NULL);
+ if (WARN_ON(!knparent))
+ return ERR_PTR(-EINVAL);
+
+ do {
+ struct dentry *dtmp;
+ struct kernfs_node *kntmp;
+
+ if (kn == knparent)
+ return dentry;
+ kntmp = find_next_ancestor(kn, knparent);
+ if (WARN_ON(!kntmp))
+ return ERR_PTR(-EINVAL);
+ dtmp = lookup_one_len(kntmp->name, dentry, strlen(kntmp->name));
+ dput(dentry);
+ if (IS_ERR(dtmp))
+ return dtmp;
+ knparent = kntmp;
+ dentry = dtmp;
+ } while (1);
+}
+
static int kernfs_fill_super(struct super_block *sb, unsigned long magic)
{
struct kernfs_super_info *info = kernfs_info(sb);
diff --git a/include/linux/kernfs.h b/include/linux/kernfs.h
index 716bfde..c06c442 100644
--- a/include/linux/kernfs.h
+++ b/include/linux/kernfs.h
@@ -284,6 +284,8 @@ struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry);
struct kernfs_root *kernfs_root_from_sb(struct super_block *sb);
struct inode *kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn);
+struct dentry *kernfs_node_dentry(struct kernfs_node *kn,
+ struct super_block *sb);
struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
unsigned int flags, void *priv);
void kernfs_destroy_root(struct kernfs_root *root);
--
1.7.9.5
^ permalink raw reply related [flat|nested] 19+ messages in thread
* [PATCH 6/8] cgroup: mount cgroupns-root when inside non-init cgroupns
2016-01-04 19:54 CGroup Namespaces (v9) serge.hallyn
` (4 preceding siblings ...)
2016-01-04 19:54 ` [PATCH 5/8] kernfs: define kernfs_node_dentry serge.hallyn
@ 2016-01-04 19:54 ` serge.hallyn
2016-01-04 19:54 ` [PATCH 7/8] cgroup: Add documentation for cgroup namespaces serge.hallyn
` (2 subsequent siblings)
8 siblings, 0 replies; 19+ messages in thread
From: serge.hallyn @ 2016-01-04 19:54 UTC (permalink / raw)
To: linux-kernel
Cc: adityakali, tj, linux-api, containers, cgroups, lxc-devel, akpm,
ebiederm, gregkh, lizefan, hannes, Serge Hallyn, Serge Hallyn
From: Serge Hallyn <serge.hallyn@ubuntu.com>
This patch enables cgroup mounting inside userns when a process
as appropriate privileges. The cgroup filesystem mounted is
rooted at the cgroupns-root. Thus, in a container-setup, only
the hierarchy under the cgroupns-root is exposed inside the container.
This allows container management tools to run inside the containers
without depending on any global state.
Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
---
Changelog:
20151116 - Don't allow user namespaces to bind new subsystems
20151118 - postpone the FS_USERNS_MOUNT flag until the
last patch, until we can convince ourselves it
is safe.
20151207 - Switch to walking up the kernfs path from kn root.
- Group initialized variables
- Explain the capable(CAP_SYS_ADMIN) check
- Style fixes
20160104 - kernfs_node_dentry: lock inode for lookup_one_len()
Signed-off-by: Serge Hallyn <serge.hallyn@ubuntu.com>
---
fs/kernfs/mount.c | 2 ++
kernel/cgroup.c | 40 +++++++++++++++++++++++++++++++++++++++-
2 files changed, 41 insertions(+), 1 deletion(-)
diff --git a/fs/kernfs/mount.c b/fs/kernfs/mount.c
index 7224296..074bb8b 100644
--- a/fs/kernfs/mount.c
+++ b/fs/kernfs/mount.c
@@ -120,7 +120,9 @@ struct dentry *kernfs_node_dentry(struct kernfs_node *kn,
kntmp = find_next_ancestor(kn, knparent);
if (WARN_ON(!kntmp))
return ERR_PTR(-EINVAL);
+ mutex_lock(&d_inode(dentry)->i_mutex);
dtmp = lookup_one_len(kntmp->name, dentry, strlen(kntmp->name));
+ mutex_unlock(&d_inode(dentry)->i_mutex);
dput(dentry);
if (IS_ERR(dtmp))
return dtmp;
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2bb58a1..d0bed8f 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -1983,6 +1983,7 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
{
bool is_v2 = fs_type == &cgroup2_fs_type;
struct super_block *pinned_sb = NULL;
+ struct cgroup_namespace *ns = current->nsproxy->cgroup_ns;
struct cgroup_subsys *ss;
struct cgroup_root *root;
struct cgroup_sb_opts opts;
@@ -1991,6 +1992,14 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
int i;
bool new_sb;
+ get_cgroup_ns(ns);
+
+ /* Check if the caller has permission to mount. */
+ if (!ns_capable(ns->user_ns, CAP_SYS_ADMIN)) {
+ put_cgroup_ns(ns);
+ return ERR_PTR(-EPERM);
+ }
+
/*
* The first time anyone tries to mount a cgroup, enable the list
* linking each css_set to its tasks and fix up all existing tasks.
@@ -2106,6 +2115,16 @@ static struct dentry *cgroup_mount(struct file_system_type *fs_type,
goto out_unlock;
}
+ /*
+ * We know this subsystem has not yet been bound. Users in a non-init
+ * user namespace may only mount hierarchies with no bound subsystems,
+ * i.e. 'none,name=user1'
+ */
+ if (!opts.none && !capable(CAP_SYS_ADMIN)) {
+ ret = -EPERM;
+ goto out_unlock;
+ }
+
root = kzalloc(sizeof(*root), GFP_KERNEL);
if (!root) {
ret = -ENOMEM;
@@ -2124,12 +2143,30 @@ out_free:
kfree(opts.release_agent);
kfree(opts.name);
- if (ret)
+ if (ret) {
+ put_cgroup_ns(ns);
return ERR_PTR(ret);
+ }
out_mount:
dentry = kernfs_mount(fs_type, flags, root->kf_root,
is_v2 ? CGROUP2_SUPER_MAGIC : CGROUP_SUPER_MAGIC,
&new_sb);
+
+ /*
+ * In non-init cgroup namespace, instead of root cgroup's
+ * dentry, we return the dentry corresponding to the
+ * cgroupns->root_cgrp.
+ */
+ if (!IS_ERR(dentry) && ns != &init_cgroup_ns) {
+ struct dentry *nsdentry;
+ struct cgroup *cgrp;
+
+ cgrp = cset_cgroup_from_root(ns->root_cset, root);
+ nsdentry = kernfs_node_dentry(cgrp->kn, dentry->d_sb);
+ dput(dentry);
+ dentry = nsdentry;
+ }
+
if (IS_ERR(dentry) || !new_sb)
cgroup_put(&root->cgrp);
@@ -2142,6 +2179,7 @@ out_mount:
deactivate_super(pinned_sb);
}
+ put_cgroup_ns(ns);
return dentry;
}
--
1.7.9.5
^ permalink raw reply related [flat|nested] 19+ messages in thread
* [PATCH 7/8] cgroup: Add documentation for cgroup namespaces
2016-01-04 19:54 CGroup Namespaces (v9) serge.hallyn
` (5 preceding siblings ...)
2016-01-04 19:54 ` [PATCH 6/8] cgroup: mount cgroupns-root when inside non-init cgroupns serge.hallyn
@ 2016-01-04 19:54 ` serge.hallyn
2016-01-04 19:54 ` [PATCH 8/8] Add FS_USERNS_FLAG to cgroup fs serge.hallyn
2016-01-05 0:53 ` CGroup Namespaces (v9) Serge E. Hallyn
8 siblings, 0 replies; 19+ messages in thread
From: serge.hallyn @ 2016-01-04 19:54 UTC (permalink / raw)
To: linux-kernel
Cc: adityakali, tj, linux-api, containers, cgroups, lxc-devel, akpm,
ebiederm, gregkh, lizefan, hannes, Serge Hallyn, Serge Hallyn
From: Serge Hallyn <serge.hallyn@ubuntu.com>
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
---
Changelog (2015-12-08):
Merge into Documentation/cgroup.txt
Changelog (2015-12-22):
Reformat to try to follow the style of the rest of the cgroup.txt file.
Changelog (2015-12-22):
tj: Reorganized to better fit the documentation.
---
Documentation/cgroup.txt | 147 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 147 insertions(+)
diff --git a/Documentation/cgroup.txt b/Documentation/cgroup.txt
index 31d1f7b..983ba63 100644
--- a/Documentation/cgroup.txt
+++ b/Documentation/cgroup.txt
@@ -47,6 +47,11 @@ CONTENTS
5-3. IO
5-3-1. IO Interface Files
5-3-2. Writeback
+6. Namespace
+ 6-1. Basics
+ 6-2. The Root and Views
+ 6-3. Migration and setns(2)
+ 6-4. Interaction with Other Namespaces
P. Information on Kernel Programming
P-1. Filesystem Support for Writeback
D. Deprecated v1 Core Features
@@ -1013,6 +1018,148 @@ writeback as follows.
vm.dirty[_background]_ratio.
+6. Namespace
+
+6-1. Basics
+
+cgroup namespace provides a mechanism to virtualize the view of the
+"/proc/$PID/cgroup" file and cgroup mounts. The CLONE_NEWCGROUP clone
+flag can be used with clone(2) and unshare(2) to create a new cgroup
+namespace. The process running inside the cgroup namespace will have
+its "/proc/$PID/cgroup" output restricted to cgroupns root. The
+cgroupns root is the cgroup of the process at the time of creation of
+the cgroup namespace.
+
+Without cgroup namespace, the "/proc/$PID/cgroup" file shows the
+complete path of the cgroup of a process. In a container setup where
+a set of cgroups and namespaces are intended to isolate processes the
+"/proc/$PID/cgroup" file may leak potential system level information
+to the isolated processes. For Example:
+
+ # cat /proc/self/cgroup
+ 0::/batchjobs/container_id1
+
+The path '/batchjobs/container_id1' can be considered as system-data
+and undesirable to expose to the isolated processes. cgroup namespace
+can be used to restrict visibility of this path. For example, before
+creating a cgroup namespace, one would see:
+
+ # ls -l /proc/self/ns/cgroup
+ lrwxrwxrwx 1 root root 0 2014-07-15 10:37 /proc/self/ns/cgroup -> cgroup:[4026531835]
+ # cat /proc/self/cgroup
+ 0::/batchjobs/container_id1
+
+After unsharing a new namespace, the view changes.
+
+ # ls -l /proc/self/ns/cgroup
+ lrwxrwxrwx 1 root root 0 2014-07-15 10:35 /proc/self/ns/cgroup -> cgroup:[4026532183]
+ # cat /proc/self/cgroup
+ 0::/
+
+When some thread from a multi-threaded process unshares its cgroup
+namespace, the new cgroupns gets applied to the entire process (all
+the threads). This is natural for the v2 hierarchy; however, for the
+legacy hierarchies, this may be unexpected.
+
+A cgroup namespace is alive as long as there are processes inside or
+mounts pinning it. When the last usage goes away, the cgroup
+namespace is destroyed. The cgroupns root and the actual cgroups
+remain.
+
+
+6-2. The Root and Views
+
+The 'cgroupns root' for a cgroup namespace is the cgroup in which the
+process calling unshare(2) is running. For example, if a process in
+/batchjobs/container_id1 cgroup calls unshare, cgroup
+/batchjobs/container_id1 becomes the cgroupns root. For the
+init_cgroup_ns, this is the real root ('/') cgroup.
+
+The cgroupns root cgroup does not change even if the namespace creator
+process later moves to a different cgroup.
+
+ # ~/unshare -c # unshare cgroupns in some cgroup
+ # cat /proc/self/cgroup
+ 0::/
+ # mkdir sub_cgrp_1
+ # echo 0 > sub_cgrp_1/cgroup.procs
+ # cat /proc/self/cgroup
+ 0::/sub_cgrp_1
+
+Each process gets its namespace-specific view of "/proc/$PID/cgroup"
+
+Processes running inside the cgroup namespace will be able to see
+cgroup paths (in /proc/self/cgroup) only inside their root cgroup.
+From within an unshared cgroupns:
+
+ # sleep 100000 &
+ [1] 7353
+ # echo 7353 > sub_cgrp_1/cgroup.procs
+ # cat /proc/7353/cgroup
+ 0::/sub_cgrp_1
+
+From the initial cgroup namespace, the real cgroup path will be
+visible:
+
+ $ cat /proc/7353/cgroup
+ 0::/batchjobs/container_id1/sub_cgrp_1
+
+From a sibling cgroup namespace (that is, a namespace rooted at a
+different cgroup), the cgroup path relative to its own cgroup
+namespace root will be shown. For instance, if PID 7353's cgroup
+namespace root is at '/batchjobs/container_id2', then it will see
+
+ # cat /proc/7353/cgroup
+ 0::/../container_id2/sub_cgrp_1
+
+Note that the relative path always starts with '/' to indicate that
+its relative to the cgroup namespace root of the caller.
+
+
+6-3. Migration and setns(2)
+
+Processes inside a cgroup namespace can move into and out of the
+namespace root if they have proper access to external cgroups. For
+example, from inside a namespace with cgroupns root at
+/batchjobs/container_id1, and assuming that the global hierarchy is
+still accessible inside cgroupns:
+
+ # cat /proc/7353/cgroup
+ 0::/sub_cgrp_1
+ # echo 7353 > batchjobs/container_id2/cgroup.procs
+ # cat /proc/7353/cgroup
+ 0::/../container_id2
+
+Note that this kind of setup is not encouraged. A task inside cgroup
+namespace should only be exposed to its own cgroupns hierarchy.
+
+setns(2) to another cgroup namespace is allowed when:
+
+(a) the process has CAP_SYS_ADMIN against its current user namespace
+(b) the process has CAP_SYS_ADMIN against the target cgroup
+ namespace's userns
+
+No implicit cgroup changes happen with attaching to another cgroup
+namespace. It is expected that the someone moves the attaching
+process under the target cgroup namespace root.
+
+
+6-4. Interaction with Other Namespaces
+
+Namespace specific cgroup hierarchy can be mounted by a process
+running inside a non-init cgroup namespace.
+
+ # mount -t cgroup2 none $MOUNT_POINT
+
+This will mount the unified cgroup hierarchy with cgroupns root as the
+filesystem root. The process needs CAP_SYS_ADMIN against its user and
+mount namespaces.
+
+The virtualization of /proc/self/cgroup file combined with restricting
+the view of cgroup hierarchy by namespace-private cgroupfs mount
+provides a properly isolated cgroup view inside the container.
+
+
P. Information on Kernel Programming
This section contains kernel programming information in the areas
--
1.7.9.5
^ permalink raw reply related [flat|nested] 19+ messages in thread
* [PATCH 8/8] Add FS_USERNS_FLAG to cgroup fs
2016-01-04 19:54 CGroup Namespaces (v9) serge.hallyn
` (6 preceding siblings ...)
2016-01-04 19:54 ` [PATCH 7/8] cgroup: Add documentation for cgroup namespaces serge.hallyn
@ 2016-01-04 19:54 ` serge.hallyn
2016-01-05 0:53 ` CGroup Namespaces (v9) Serge E. Hallyn
8 siblings, 0 replies; 19+ messages in thread
From: serge.hallyn @ 2016-01-04 19:54 UTC (permalink / raw)
To: linux-kernel
Cc: adityakali, tj, linux-api, containers, cgroups, lxc-devel, akpm,
ebiederm, gregkh, lizefan, hannes, Serge Hallyn, Serge Hallyn
From: Serge Hallyn <serge.hallyn@ubuntu.com>
allowing root in a non-init user namespace to mount it. This should
now be safe, because
1. non-init-root cannot mount a previously unbound subsystem
2. the task doing the mount must be privileged with respect to the
user namespace owning the cgroup namespace
3. the mounted subsystem will have its current cgroup as the root dentry.
the permissions will be unchanged, so tasks will receive no new
privilege over the cgroups which they did not have on the original
mounts.
Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
---
kernel/cgroup.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index d0bed8f..f2c47c1 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -2208,12 +2208,14 @@ static struct file_system_type cgroup_fs_type = {
.name = "cgroup",
.mount = cgroup_mount,
.kill_sb = cgroup_kill_sb,
+ .fs_flags = FS_USERNS_MOUNT,
};
static struct file_system_type cgroup2_fs_type = {
.name = "cgroup2",
.mount = cgroup_mount,
.kill_sb = cgroup_kill_sb,
+ .fs_flags = FS_USERNS_MOUNT,
};
char *
--
1.7.9.5
^ permalink raw reply related [flat|nested] 19+ messages in thread
* Re: [PATCH 3/8] cgroup: introduce cgroup namespaces
2016-01-04 19:54 ` [PATCH 3/8] cgroup: introduce cgroup namespaces serge.hallyn
@ 2016-01-04 20:20 ` Serge E. Hallyn
2016-01-04 21:47 ` Johannes Weiner
2016-01-05 2:07 ` [PATCH 3/8 v2] " Serge E. Hallyn
1 sibling, 1 reply; 19+ messages in thread
From: Serge E. Hallyn @ 2016-01-04 20:20 UTC (permalink / raw)
To: serge.hallyn
Cc: linux-kernel, adityakali, tj, linux-api, containers, cgroups,
lxc-devel, akpm, ebiederm, gregkh, lizefan, hannes, Serge Hallyn
On Mon, Jan 04, 2016 at 01:54:48PM -0600, serge.hallyn@ubuntu.com wrote:
> From: Aditya Kali <adityakali@google.com>
>
> Introduce the ability to create new cgroup namespace. The newly created
> cgroup namespace remembers the cgroup of the process at the point
> of creation of the cgroup namespace (referred as cgroupns-root).
> The main purpose of cgroup namespace is to virtualize the contents
> of /proc/self/cgroup file. Processes inside a cgroup namespace
> are only able to see paths relative to their namespace root
> (unless they are moved outside of their cgroupns-root, at which point
> they will see a relative path from their cgroupns-root).
> For a correctly setup container this enables container-tools
> (like libcontainer, lxc, lmctfy, etc.) to create completely virtualized
> containers without leaking system level cgroup hierarchy to the task.
> This patch only implements the 'unshare' part of the cgroupns.
>
> Signed-off-by: Aditya Kali <adityakali@google.com>
> Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
> ---
> Changelog: 2015-11-24
> - move cgroup_namespace.c into cgroup.c (and .h)
> - reformatting
> - make get_cgroup_ns return void
> - rename ns->root_cgrps to root_cset.
> Changelog: 2015-12-08
> - Move init_cgroup_ns to other variable declarations
> - Remove accidental conversion of put-css_set to inline
> - Drop BUG_ON(NULL)
> - Remove unneeded pre declaration of struct cgroupns_operations.
> - cgroup.h: collect common ns declerations
> Changelog: 2015-12-09
> - cgroup.h: move ns declarations to bottom
> - cgroup.c: undo all accidental conversions to inline
> Changelog: 2015-12-22
> - update for new kernfs_path_from_node() return value. Since
> cgroup_path was already gpl-exported, I abstained from updating
> its return value.
> Changelog: 2015-12-23
> - cgroup_path(): use init_cgroup_ns when in interupt context.
> Changelog: 2015-01-02
> - move to_cg_ns definition forward in patch series
> - cgroup_release_agent: grab css_set_lock around cgroup_path()
> - leave cgroup_path non-namespaced, use cgroup_path_ns when
> namespaced path is desired.
> ---
> fs/proc/namespaces.c | 3 +
> include/linux/cgroup.h | 56 +++++++++++++--
> include/linux/nsproxy.h | 2 +
> include/linux/proc_ns.h | 4 ++
> kernel/cgroup.c | 177 ++++++++++++++++++++++++++++++++++++++++++++++-
> kernel/cpuset.c | 3 +-
> kernel/fork.c | 2 +-
> kernel/nsproxy.c | 21 +++++-
> kernel/sched/debug.c | 3 +-
> 9 files changed, 257 insertions(+), 14 deletions(-)
>
> diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
> index f6e8354..bd61075 100644
> --- a/fs/proc/namespaces.c
> +++ b/fs/proc/namespaces.c
> @@ -28,6 +28,9 @@ static const struct proc_ns_operations *ns_entries[] = {
> &userns_operations,
> #endif
> &mntns_operations,
> +#ifdef CONFIG_CGROUPS
> + &cgroupns_operations,
> +#endif
> };
>
> static const char *proc_ns_follow_link(struct dentry *dentry, void **cookie)
> diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
> index 9d70b48..149ae0a 100644
> --- a/include/linux/cgroup.h
> +++ b/include/linux/cgroup.h
> @@ -17,6 +17,11 @@
> #include <linux/seq_file.h>
> #include <linux/kernfs.h>
> #include <linux/jump_label.h>
> +#include <linux/nsproxy.h>
> +#include <linux/types.h>
> +#include <linux/ns_common.h>
> +#include <linux/nsproxy.h>
> +#include <linux/user_namespace.h>
>
> #include <linux/cgroup-defs.h>
>
> @@ -532,12 +537,6 @@ static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen)
> return kernfs_name(cgrp->kn, buf, buflen);
> }
>
> -static inline char * __must_check cgroup_path(struct cgroup *cgrp, char *buf,
> - size_t buflen)
> -{
> - return kernfs_path(cgrp->kn, buf, buflen);
> -}
> -
> static inline void pr_cont_cgroup_name(struct cgroup *cgrp)
> {
> pr_cont_kernfs_name(cgrp->kn);
> @@ -570,4 +569,49 @@ static inline int cgroup_init(void) { return 0; }
>
> #endif /* !CONFIG_CGROUPS */
>
> +struct cgroup_namespace {
> + atomic_t count;
> + struct ns_common ns;
> + struct user_namespace *user_ns;
> + struct css_set *root_cset;
> +};
> +
> +extern struct cgroup_namespace init_cgroup_ns;
> +
> +#ifdef CONFIG_CGROUPS
> +
> +void free_cgroup_ns(struct cgroup_namespace *ns);
> +
> +struct cgroup_namespace *
> +copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
> + struct cgroup_namespace *old_ns);
> +
> +char *cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
> + struct cgroup_namespace *ns);
> +char *cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen);
> +
> +#else /* !CONFIG_CGROUPS */
> +
> +static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
> +static inline struct cgroup_namespace *
> +copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
> + struct cgroup_namespace *old_ns)
> +{
> + return old_ns;
> +}
> +
> +#endif /* !CONFIG_CGROUPS */
> +
> +static inline void get_cgroup_ns(struct cgroup_namespace *ns)
> +{
> + if (ns)
> + atomic_inc(&ns->count);
> +}
> +
> +static inline void put_cgroup_ns(struct cgroup_namespace *ns)
> +{
> + if (ns && atomic_dec_and_test(&ns->count))
> + free_cgroup_ns(ns);
> +}
> +
> #endif /* _LINUX_CGROUP_H */
> diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
> index 35fa08f..ac0d65b 100644
> --- a/include/linux/nsproxy.h
> +++ b/include/linux/nsproxy.h
> @@ -8,6 +8,7 @@ struct mnt_namespace;
> struct uts_namespace;
> struct ipc_namespace;
> struct pid_namespace;
> +struct cgroup_namespace;
> struct fs_struct;
>
> /*
> @@ -33,6 +34,7 @@ struct nsproxy {
> struct mnt_namespace *mnt_ns;
> struct pid_namespace *pid_ns_for_children;
> struct net *net_ns;
> + struct cgroup_namespace *cgroup_ns;
> };
> extern struct nsproxy init_nsproxy;
>
> diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h
> index 42dfc61..de0e771 100644
> --- a/include/linux/proc_ns.h
> +++ b/include/linux/proc_ns.h
> @@ -9,6 +9,8 @@
> struct pid_namespace;
> struct nsproxy;
> struct path;
> +struct task_struct;
> +struct inode;
>
> struct proc_ns_operations {
> const char *name;
> @@ -24,6 +26,7 @@ extern const struct proc_ns_operations ipcns_operations;
> extern const struct proc_ns_operations pidns_operations;
> extern const struct proc_ns_operations userns_operations;
> extern const struct proc_ns_operations mntns_operations;
> +extern const struct proc_ns_operations cgroupns_operations;
>
> /*
> * We always define these enumerators
> @@ -34,6 +37,7 @@ enum {
> PROC_UTS_INIT_INO = 0xEFFFFFFEU,
> PROC_USER_INIT_INO = 0xEFFFFFFDU,
> PROC_PID_INIT_INO = 0xEFFFFFFCU,
> + PROC_CGROUP_INIT_INO = 0xEFFFFFFBU,
> };
>
> #ifdef CONFIG_PROC_FS
> diff --git a/kernel/cgroup.c b/kernel/cgroup.c
> index 6b33631..60270b1 100644
> --- a/kernel/cgroup.c
> +++ b/kernel/cgroup.c
> @@ -57,6 +57,9 @@
> #include <linux/vmalloc.h> /* TODO: replace with more sophisticated array */
> #include <linux/kthread.h>
> #include <linux/delay.h>
> +#include <linux/proc_ns.h>
> +#include <linux/nsproxy.h>
> +#include <linux/proc_ns.h>
>
> #include <linux/atomic.h>
>
> @@ -208,6 +211,15 @@ static unsigned long have_fork_callback __read_mostly;
> static unsigned long have_exit_callback __read_mostly;
> static unsigned long have_free_callback __read_mostly;
>
> +/* Cgroup namespace for init task */
> +struct cgroup_namespace init_cgroup_ns = {
> + .count = { .counter = 2, },
> + .user_ns = &init_user_ns,
> + .ns.ops = &cgroupns_operations,
> + .ns.inum = PROC_CGROUP_INIT_INO,
> + .root_cset = &init_css_set,
> +};
> +
> /* Ditto for the can_fork callback. */
> static unsigned long have_canfork_callback __read_mostly;
>
> @@ -2166,6 +2178,43 @@ static struct file_system_type cgroup2_fs_type = {
> .kill_sb = cgroup_kill_sb,
> };
>
> +char *
Sorry, that one should be 'static char *'
> +cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
> + struct cgroup_namespace *ns)
> +{
> + int ret;
> + struct cgroup *root = cset_cgroup_from_root(ns->root_cset, cgrp->root);
> +
> + ret = kernfs_path_from_node(cgrp->kn, root->kn, buf, buflen);
> + if (ret < 0 || ret >= buflen)
> + return NULL;
> + return buf;
> +}
> +
> +char *cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
> + struct cgroup_namespace *ns)
> +{
> + char *ret;
> +
> + mutex_lock(&cgroup_mutex);
> + spin_lock_bh(&css_set_lock);
> +
> + ret = cgroup_path_ns_locked(cgrp, buf, buflen, ns);
> +
> + spin_unlock_bh(&css_set_lock);
> + mutex_unlock(&cgroup_mutex);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(cgroup_path_ns);
> +
> +char *cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen)
> +{
> + return cgroup_path_ns(cgrp, buf, buflen, &init_cgroup_ns);
> +}
> +
> +EXPORT_SYMBOL_GPL(cgroup_path);
> +
> /**
> * task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
> * @task: target task
> @@ -2193,7 +2242,8 @@ char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
>
> if (root) {
> cgrp = task_cgroup_from_root(task, root);
> - path = cgroup_path(cgrp, buf, buflen);
> + path = cgroup_path_ns_locked(cgrp, buf, buflen,
> + &init_cgroup_ns);
> } else {
> /* if no hierarchy exists, everyone is in "/" */
> if (strlcpy(buf, "/", buflen) < buflen)
> @@ -5272,6 +5322,8 @@ int __init cgroup_init(void)
> BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
> BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));
>
> + get_user_ns(init_cgroup_ns.user_ns);
> +
> mutex_lock(&cgroup_mutex);
>
> /* Add init_css_set to the hash table */
> @@ -5409,7 +5461,8 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
> * " (deleted)" is appended to the cgroup path.
> */
> if (cgroup_on_dfl(cgrp) || !(tsk->flags & PF_EXITING)) {
> - path = cgroup_path(cgrp, buf, PATH_MAX);
> + path = cgroup_path_ns_locked(cgrp, buf, PATH_MAX,
> + current->nsproxy->cgroup_ns);
> if (!path) {
> retval = -ENAMETOOLONG;
> goto out_unlock;
> @@ -5691,7 +5744,10 @@ static void cgroup_release_agent(struct work_struct *work)
> if (!pathbuf || !agentbuf)
> goto out;
>
> - path = cgroup_path(cgrp, pathbuf, PATH_MAX);
> + spin_lock_bh(&css_set_lock);
> + path = cgroup_path_ns_locked(cgrp, pathbuf, PATH_MAX,
> + &init_cgroup_ns);
> + spin_unlock_bh(&css_set_lock);
> if (!path)
> goto out;
>
> @@ -5822,6 +5878,121 @@ struct cgroup *cgroup_get_from_path(const char *path)
> }
> EXPORT_SYMBOL_GPL(cgroup_get_from_path);
>
> +/* cgroup namespaces */
> +
> +static struct cgroup_namespace *alloc_cgroup_ns(void)
> +{
> + struct cgroup_namespace *new_ns;
> + int ret;
> +
> + new_ns = kzalloc(sizeof(struct cgroup_namespace), GFP_KERNEL);
> + if (!new_ns)
> + return ERR_PTR(-ENOMEM);
> + ret = ns_alloc_inum(&new_ns->ns);
> + if (ret) {
> + kfree(new_ns);
> + return ERR_PTR(ret);
> + }
> + atomic_set(&new_ns->count, 1);
> + new_ns->ns.ops = &cgroupns_operations;
> + return new_ns;
> +}
> +
> +void free_cgroup_ns(struct cgroup_namespace *ns)
> +{
> + put_css_set(ns->root_cset);
> + put_user_ns(ns->user_ns);
> + ns_free_inum(&ns->ns);
> + kfree(ns);
> +}
> +EXPORT_SYMBOL(free_cgroup_ns);
> +
> +struct cgroup_namespace *
> +copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
> + struct cgroup_namespace *old_ns)
> +{
> + struct cgroup_namespace *new_ns = NULL;
> + struct css_set *cset = NULL;
> + int err;
> +
> + BUG_ON(!old_ns);
> +
> + if (!(flags & CLONE_NEWCGROUP)) {
> + get_cgroup_ns(old_ns);
> + return old_ns;
> + }
> +
> + /* Allow only sysadmin to create cgroup namespace. */
> + err = -EPERM;
> + if (!ns_capable(user_ns, CAP_SYS_ADMIN))
> + goto err_out;
> +
> + cset = task_css_set(current);
> + get_css_set(cset);
> +
> + err = -ENOMEM;
> + new_ns = alloc_cgroup_ns();
> + if (!new_ns)
> + goto err_out;
> +
> + new_ns->user_ns = get_user_ns(user_ns);
> + new_ns->root_cset = cset;
> +
> + return new_ns;
> +
> +err_out:
> + if (cset)
> + put_css_set(cset);
> + kfree(new_ns);
> + return ERR_PTR(err);
> +}
> +
> +static inline struct cgroup_namespace *to_cg_ns(struct ns_common *ns)
> +{
> + return container_of(ns, struct cgroup_namespace, ns);
> +}
> +
> +static int cgroupns_install(struct nsproxy *nsproxy, void *ns)
> +{
> + pr_info("setns not supported for cgroup namespace");
> + return -EINVAL;
> +}
> +
> +static struct ns_common *cgroupns_get(struct task_struct *task)
> +{
> + struct cgroup_namespace *ns = NULL;
> + struct nsproxy *nsproxy;
> +
> + task_lock(task);
> + nsproxy = task->nsproxy;
> + if (nsproxy) {
> + ns = nsproxy->cgroup_ns;
> + get_cgroup_ns(ns);
> + }
> + task_unlock(task);
> +
> + return ns ? &ns->ns : NULL;
> +}
> +
> +static void cgroupns_put(struct ns_common *ns)
> +{
> + put_cgroup_ns(to_cg_ns(ns));
> +}
> +
> +const struct proc_ns_operations cgroupns_operations = {
> + .name = "cgroup",
> + .type = CLONE_NEWCGROUP,
> + .get = cgroupns_get,
> + .put = cgroupns_put,
> + .install = cgroupns_install,
> +};
> +
> +static __init int cgroup_namespaces_init(void)
> +{
> + return 0;
> +}
> +subsys_initcall(cgroup_namespaces_init);
> +
> #ifdef CONFIG_CGROUP_DEBUG
> static struct cgroup_subsys_state *
> debug_css_alloc(struct cgroup_subsys_state *parent_css)
> diff --git a/kernel/cpuset.c b/kernel/cpuset.c
> index 3e945fc..37c8eb0 100644
> --- a/kernel/cpuset.c
> +++ b/kernel/cpuset.c
> @@ -2689,7 +2689,8 @@ int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
> retval = -ENAMETOOLONG;
> rcu_read_lock();
> css = task_css(tsk, cpuset_cgrp_id);
> - p = cgroup_path(css->cgroup, buf, PATH_MAX);
> + p = cgroup_path_ns(css->cgroup, buf, PATH_MAX,
> + current->nsproxy->cgroup_ns);
> rcu_read_unlock();
> if (!p)
> goto out_free;
> diff --git a/kernel/fork.c b/kernel/fork.c
> index ba7d1c0..7982fee 100644
> --- a/kernel/fork.c
> +++ b/kernel/fork.c
> @@ -1880,7 +1880,7 @@ static int check_unshare_flags(unsigned long unshare_flags)
> if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
> CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
> CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET|
> - CLONE_NEWUSER|CLONE_NEWPID))
> + CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP))
> return -EINVAL;
> /*
> * Not implemented, but pretend it works if there is nothing
> diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
> index 49746c8..64fe865 100644
> --- a/kernel/nsproxy.c
> +++ b/kernel/nsproxy.c
> @@ -25,6 +25,7 @@
> #include <linux/proc_ns.h>
> #include <linux/file.h>
> #include <linux/syscalls.h>
> +#include <linux/cgroup.h>
>
> static struct kmem_cache *nsproxy_cachep;
>
> @@ -39,6 +40,9 @@ struct nsproxy init_nsproxy = {
> #ifdef CONFIG_NET
> .net_ns = &init_net,
> #endif
> +#ifdef CONFIG_CGROUPS
> + .cgroup_ns = &init_cgroup_ns,
> +#endif
> };
>
> static inline struct nsproxy *create_nsproxy(void)
> @@ -92,6 +96,13 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
> goto out_pid;
> }
>
> + new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns,
> + tsk->nsproxy->cgroup_ns);
> + if (IS_ERR(new_nsp->cgroup_ns)) {
> + err = PTR_ERR(new_nsp->cgroup_ns);
> + goto out_cgroup;
> + }
> +
> new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
> if (IS_ERR(new_nsp->net_ns)) {
> err = PTR_ERR(new_nsp->net_ns);
> @@ -101,6 +112,9 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
> return new_nsp;
>
> out_net:
> + if (new_nsp->cgroup_ns)
> + put_cgroup_ns(new_nsp->cgroup_ns);
> +out_cgroup:
> if (new_nsp->pid_ns_for_children)
> put_pid_ns(new_nsp->pid_ns_for_children);
> out_pid:
> @@ -128,7 +142,8 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
> struct nsproxy *new_ns;
>
> if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
> - CLONE_NEWPID | CLONE_NEWNET)))) {
> + CLONE_NEWPID | CLONE_NEWNET |
> + CLONE_NEWCGROUP)))) {
> get_nsproxy(old_ns);
> return 0;
> }
> @@ -165,6 +180,8 @@ void free_nsproxy(struct nsproxy *ns)
> put_ipc_ns(ns->ipc_ns);
> if (ns->pid_ns_for_children)
> put_pid_ns(ns->pid_ns_for_children);
> + if (ns->cgroup_ns)
> + put_cgroup_ns(ns->cgroup_ns);
> put_net(ns->net_ns);
> kmem_cache_free(nsproxy_cachep, ns);
> }
> @@ -180,7 +197,7 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
> int err = 0;
>
> if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
> - CLONE_NEWNET | CLONE_NEWPID)))
> + CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP)))
> return 0;
>
> user_ns = new_cred ? new_cred->user_ns : current_user_ns();
> diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
> index 6415117..4c28523 100644
> --- a/kernel/sched/debug.c
> +++ b/kernel/sched/debug.c
> @@ -104,7 +104,8 @@ static char *task_group_path(struct task_group *tg)
> if (autogroup_path(tg, group_path, PATH_MAX))
> return group_path;
>
> - return cgroup_path(tg->css.cgroup, group_path, PATH_MAX);
> + return cgroup_path_ns(tg->css.cgroup, group_path, PATH_MAX,
> + current->nsproxy->cgroup_ns);
> }
> #endif
>
> --
> 1.7.9.5
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: [PATCH 3/8] cgroup: introduce cgroup namespaces
2016-01-04 20:20 ` Serge E. Hallyn
@ 2016-01-04 21:47 ` Johannes Weiner
0 siblings, 0 replies; 19+ messages in thread
From: Johannes Weiner @ 2016-01-04 21:47 UTC (permalink / raw)
To: Serge E. Hallyn
Cc: linux-kernel, adityakali, tj, linux-api, containers, cgroups,
lxc-devel, akpm, ebiederm, gregkh, lizefan, Serge Hallyn
On Mon, Jan 04, 2016 at 02:20:53PM -0600, Serge E. Hallyn wrote:
> On Mon, Jan 04, 2016 at 01:54:48PM -0600, serge.hallyn@ubuntu.com wrote:
> > @@ -2166,6 +2178,43 @@ static struct file_system_type cgroup2_fs_type = {
> > .kill_sb = cgroup_kill_sb,
> > };
> >
> > +char *
>
> Sorry, that one should be 'static char *'
Lol, that took a while to find. Please don't quote over 500 lines to
comment on a trivial issue of one line.
^ permalink raw reply [flat|nested] 19+ messages in thread
* Re: CGroup Namespaces (v9)
2016-01-04 19:54 CGroup Namespaces (v9) serge.hallyn
` (7 preceding siblings ...)
2016-01-04 19:54 ` [PATCH 8/8] Add FS_USERNS_FLAG to cgroup fs serge.hallyn
@ 2016-01-05 0:53 ` Serge E. Hallyn
2016-01-05 19:36 ` Serge E. Hallyn
8 siblings, 1 reply; 19+ messages in thread
From: Serge E. Hallyn @ 2016-01-05 0:53 UTC (permalink / raw)
To: serge.hallyn
Cc: linux-kernel, linux-api, containers, hannes, ebiederm, lxc-devel,
gregkh, tj, cgroups, akpm
Ok, please hold off on this, there is another locking question i need to look
into :(
^ permalink raw reply [flat|nested] 19+ messages in thread
* [PATCH 3/8 v2] cgroup: introduce cgroup namespaces
2016-01-04 19:54 ` [PATCH 3/8] cgroup: introduce cgroup namespaces serge.hallyn
2016-01-04 20:20 ` Serge E. Hallyn
@ 2016-01-05 2:07 ` Serge E. Hallyn
2016-01-06 2:17 ` [PATCH 3/8 v3] " Serge E. Hallyn
1 sibling, 1 reply; 19+ messages in thread
From: Serge E. Hallyn @ 2016-01-05 2:07 UTC (permalink / raw)
To: serge.hallyn
Cc: linux-kernel, adityakali, tj, linux-api, containers, cgroups,
lxc-devel, akpm, ebiederm, gregkh, lizefan, hannes, Serge Hallyn
Introduce the ability to create new cgroup namespace. The newly created
cgroup namespace remembers the cgroup of the process at the point
of creation of the cgroup namespace (referred as cgroupns-root).
The main purpose of cgroup namespace is to virtualize the contents
of /proc/self/cgroup file. Processes inside a cgroup namespace
are only able to see paths relative to their namespace root
(unless they are moved outside of their cgroupns-root, at which point
they will see a relative path from their cgroupns-root).
For a correctly setup container this enables container-tools
(like libcontainer, lxc, lmctfy, etc.) to create completely virtualized
containers without leaking system level cgroup hierarchy to the task.
This patch only implements the 'unshare' part of the cgroupns.
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
---
Changelog: 2015-11-24
- move cgroup_namespace.c into cgroup.c (and .h)
- reformatting
- make get_cgroup_ns return void
- rename ns->root_cgrps to root_cset.
Changelog: 2015-12-08
- Move init_cgroup_ns to other variable declarations
- Remove accidental conversion of put-css_set to inline
- Drop BUG_ON(NULL)
- Remove unneeded pre declaration of struct cgroupns_operations.
- cgroup.h: collect common ns declerations
Changelog: 2015-12-09
- cgroup.h: move ns declarations to bottom
- cgroup.c: undo all accidental conversions to inline
Changelog: 2015-12-22
- update for new kernfs_path_from_node() return value. Since
cgroup_path was already gpl-exported, I abstained from updating
its return value.
Changelog: 2015-12-23
- cgroup_path(): use init_cgroup_ns when in interupt context.
Changelog: 2015-01-02
- move to_cg_ns definition forward in patch series
- cgroup_release_agent: grab css_set_lock around cgroup_path()
- leave cgroup_path non-namespaced, use cgroup_path_ns when
namespaced path is desired.
Changelog: 2015-01-04
- cgroup_path: continue to use kernfs_path. Since cgroup_path is
non-namespaced, use the old version.
- make cgroup_path_ns_locked() static.
---
fs/proc/namespaces.c | 3 +
include/linux/cgroup.h | 49 ++++++++++++++
include/linux/nsproxy.h | 2 +
include/linux/proc_ns.h | 4 ++
kernel/cgroup.c | 170 ++++++++++++++++++++++++++++++++++++++++++++++-
kernel/cpuset.c | 3 +-
kernel/fork.c | 2 +-
kernel/nsproxy.c | 21 +++++-
kernel/sched/debug.c | 3 +-
9 files changed, 249 insertions(+), 8 deletions(-)
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index f6e8354..bd61075 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -28,6 +28,9 @@ static const struct proc_ns_operations *ns_entries[] = {
&userns_operations,
#endif
&mntns_operations,
+#ifdef CONFIG_CGROUPS
+ &cgroupns_operations,
+#endif
};
static const char *proc_ns_follow_link(struct dentry *dentry, void **cookie)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 9d70b48..f5fe730 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -17,6 +17,11 @@
#include <linux/seq_file.h>
#include <linux/kernfs.h>
#include <linux/jump_label.h>
+#include <linux/nsproxy.h>
+#include <linux/types.h>
+#include <linux/ns_common.h>
+#include <linux/nsproxy.h>
+#include <linux/user_namespace.h>
#include <linux/cgroup-defs.h>
@@ -570,4 +575,48 @@ static inline int cgroup_init(void) { return 0; }
#endif /* !CONFIG_CGROUPS */
+struct cgroup_namespace {
+ atomic_t count;
+ struct ns_common ns;
+ struct user_namespace *user_ns;
+ struct css_set *root_cset;
+};
+
+extern struct cgroup_namespace init_cgroup_ns;
+
+#ifdef CONFIG_CGROUPS
+
+void free_cgroup_ns(struct cgroup_namespace *ns);
+
+struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns);
+
+char *cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns);
+
+#else /* !CONFIG_CGROUPS */
+
+static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
+static inline struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns)
+{
+ return old_ns;
+}
+
+#endif /* !CONFIG_CGROUPS */
+
+static inline void get_cgroup_ns(struct cgroup_namespace *ns)
+{
+ if (ns)
+ atomic_inc(&ns->count);
+}
+
+static inline void put_cgroup_ns(struct cgroup_namespace *ns)
+{
+ if (ns && atomic_dec_and_test(&ns->count))
+ free_cgroup_ns(ns);
+}
+
#endif /* _LINUX_CGROUP_H */
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 35fa08f..ac0d65b 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -8,6 +8,7 @@ struct mnt_namespace;
struct uts_namespace;
struct ipc_namespace;
struct pid_namespace;
+struct cgroup_namespace;
struct fs_struct;
/*
@@ -33,6 +34,7 @@ struct nsproxy {
struct mnt_namespace *mnt_ns;
struct pid_namespace *pid_ns_for_children;
struct net *net_ns;
+ struct cgroup_namespace *cgroup_ns;
};
extern struct nsproxy init_nsproxy;
diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h
index 42dfc61..de0e771 100644
--- a/include/linux/proc_ns.h
+++ b/include/linux/proc_ns.h
@@ -9,6 +9,8 @@
struct pid_namespace;
struct nsproxy;
struct path;
+struct task_struct;
+struct inode;
struct proc_ns_operations {
const char *name;
@@ -24,6 +26,7 @@ extern const struct proc_ns_operations ipcns_operations;
extern const struct proc_ns_operations pidns_operations;
extern const struct proc_ns_operations userns_operations;
extern const struct proc_ns_operations mntns_operations;
+extern const struct proc_ns_operations cgroupns_operations;
/*
* We always define these enumerators
@@ -34,6 +37,7 @@ enum {
PROC_UTS_INIT_INO = 0xEFFFFFFEU,
PROC_USER_INIT_INO = 0xEFFFFFFDU,
PROC_PID_INIT_INO = 0xEFFFFFFCU,
+ PROC_CGROUP_INIT_INO = 0xEFFFFFFBU,
};
#ifdef CONFIG_PROC_FS
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 6b33631..68b84ba 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -57,6 +57,9 @@
#include <linux/vmalloc.h> /* TODO: replace with more sophisticated array */
#include <linux/kthread.h>
#include <linux/delay.h>
+#include <linux/proc_ns.h>
+#include <linux/nsproxy.h>
+#include <linux/proc_ns.h>
#include <linux/atomic.h>
@@ -208,6 +211,15 @@ static unsigned long have_fork_callback __read_mostly;
static unsigned long have_exit_callback __read_mostly;
static unsigned long have_free_callback __read_mostly;
+/* Cgroup namespace for init task */
+struct cgroup_namespace init_cgroup_ns = {
+ .count = { .counter = 2, },
+ .user_ns = &init_user_ns,
+ .ns.ops = &cgroupns_operations,
+ .ns.inum = PROC_CGROUP_INIT_INO,
+ .root_cset = &init_css_set,
+};
+
/* Ditto for the can_fork callback. */
static unsigned long have_canfork_callback __read_mostly;
@@ -2166,6 +2178,36 @@ static struct file_system_type cgroup2_fs_type = {
.kill_sb = cgroup_kill_sb,
};
+static char *
+cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns)
+{
+ int ret;
+ struct cgroup *root = cset_cgroup_from_root(ns->root_cset, cgrp->root);
+
+ ret = kernfs_path_from_node(cgrp->kn, root->kn, buf, buflen);
+ if (ret < 0 || ret >= buflen)
+ return NULL;
+ return buf;
+}
+
+char *cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns)
+{
+ char *ret;
+
+ mutex_lock(&cgroup_mutex);
+ spin_lock_bh(&css_set_lock);
+
+ ret = cgroup_path_ns_locked(cgrp, buf, buflen, ns);
+
+ spin_unlock_bh(&css_set_lock);
+ mutex_unlock(&cgroup_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(cgroup_path_ns);
+
/**
* task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
* @task: target task
@@ -2193,7 +2235,8 @@ char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
if (root) {
cgrp = task_cgroup_from_root(task, root);
- path = cgroup_path(cgrp, buf, buflen);
+ path = cgroup_path_ns_locked(cgrp, buf, buflen,
+ &init_cgroup_ns);
} else {
/* if no hierarchy exists, everyone is in "/" */
if (strlcpy(buf, "/", buflen) < buflen)
@@ -5272,6 +5315,8 @@ int __init cgroup_init(void)
BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));
+ get_user_ns(init_cgroup_ns.user_ns);
+
mutex_lock(&cgroup_mutex);
/* Add init_css_set to the hash table */
@@ -5409,7 +5454,8 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
* " (deleted)" is appended to the cgroup path.
*/
if (cgroup_on_dfl(cgrp) || !(tsk->flags & PF_EXITING)) {
- path = cgroup_path(cgrp, buf, PATH_MAX);
+ path = cgroup_path_ns_locked(cgrp, buf, PATH_MAX,
+ current->nsproxy->cgroup_ns);
if (!path) {
retval = -ENAMETOOLONG;
goto out_unlock;
@@ -5691,7 +5737,10 @@ static void cgroup_release_agent(struct work_struct *work)
if (!pathbuf || !agentbuf)
goto out;
- path = cgroup_path(cgrp, pathbuf, PATH_MAX);
+ spin_lock_bh(&css_set_lock);
+ path = cgroup_path_ns_locked(cgrp, pathbuf, PATH_MAX,
+ &init_cgroup_ns);
+ spin_unlock_bh(&css_set_lock);
if (!path)
goto out;
@@ -5822,6 +5871,121 @@ struct cgroup *cgroup_get_from_path(const char *path)
}
EXPORT_SYMBOL_GPL(cgroup_get_from_path);
+/* cgroup namespaces */
+
+static struct cgroup_namespace *alloc_cgroup_ns(void)
+{
+ struct cgroup_namespace *new_ns;
+ int ret;
+
+ new_ns = kzalloc(sizeof(struct cgroup_namespace), GFP_KERNEL);
+ if (!new_ns)
+ return ERR_PTR(-ENOMEM);
+ ret = ns_alloc_inum(&new_ns->ns);
+ if (ret) {
+ kfree(new_ns);
+ return ERR_PTR(ret);
+ }
+ atomic_set(&new_ns->count, 1);
+ new_ns->ns.ops = &cgroupns_operations;
+ return new_ns;
+}
+
+void free_cgroup_ns(struct cgroup_namespace *ns)
+{
+ put_css_set(ns->root_cset);
+ put_user_ns(ns->user_ns);
+ ns_free_inum(&ns->ns);
+ kfree(ns);
+}
+EXPORT_SYMBOL(free_cgroup_ns);
+
+struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns)
+{
+ struct cgroup_namespace *new_ns = NULL;
+ struct css_set *cset = NULL;
+ int err;
+
+ BUG_ON(!old_ns);
+
+ if (!(flags & CLONE_NEWCGROUP)) {
+ get_cgroup_ns(old_ns);
+ return old_ns;
+ }
+
+ /* Allow only sysadmin to create cgroup namespace. */
+ err = -EPERM;
+ if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+ goto err_out;
+
+ cset = task_css_set(current);
+ get_css_set(cset);
+
+ err = -ENOMEM;
+ new_ns = alloc_cgroup_ns();
+ if (!new_ns)
+ goto err_out;
+
+ new_ns->user_ns = get_user_ns(user_ns);
+ new_ns->root_cset = cset;
+
+ return new_ns;
+
+err_out:
+ if (cset)
+ put_css_set(cset);
+ kfree(new_ns);
+ return ERR_PTR(err);
+}
+
+static inline struct cgroup_namespace *to_cg_ns(struct ns_common *ns)
+{
+ return container_of(ns, struct cgroup_namespace, ns);
+}
+
+static int cgroupns_install(struct nsproxy *nsproxy, void *ns)
+{
+ pr_info("setns not supported for cgroup namespace");
+ return -EINVAL;
+}
+
+static struct ns_common *cgroupns_get(struct task_struct *task)
+{
+ struct cgroup_namespace *ns = NULL;
+ struct nsproxy *nsproxy;
+
+ task_lock(task);
+ nsproxy = task->nsproxy;
+ if (nsproxy) {
+ ns = nsproxy->cgroup_ns;
+ get_cgroup_ns(ns);
+ }
+ task_unlock(task);
+
+ return ns ? &ns->ns : NULL;
+}
+
+static void cgroupns_put(struct ns_common *ns)
+{
+ put_cgroup_ns(to_cg_ns(ns));
+}
+
+const struct proc_ns_operations cgroupns_operations = {
+ .name = "cgroup",
+ .type = CLONE_NEWCGROUP,
+ .get = cgroupns_get,
+ .put = cgroupns_put,
+ .install = cgroupns_install,
+};
+
+static __init int cgroup_namespaces_init(void)
+{
+ return 0;
+}
+subsys_initcall(cgroup_namespaces_init);
+
#ifdef CONFIG_CGROUP_DEBUG
static struct cgroup_subsys_state *
debug_css_alloc(struct cgroup_subsys_state *parent_css)
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 3e945fc..37c8eb0 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2689,7 +2689,8 @@ int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
retval = -ENAMETOOLONG;
rcu_read_lock();
css = task_css(tsk, cpuset_cgrp_id);
- p = cgroup_path(css->cgroup, buf, PATH_MAX);
+ p = cgroup_path_ns(css->cgroup, buf, PATH_MAX,
+ current->nsproxy->cgroup_ns);
rcu_read_unlock();
if (!p)
goto out_free;
diff --git a/kernel/fork.c b/kernel/fork.c
index ba7d1c0..7982fee 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1880,7 +1880,7 @@ static int check_unshare_flags(unsigned long unshare_flags)
if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET|
- CLONE_NEWUSER|CLONE_NEWPID))
+ CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP))
return -EINVAL;
/*
* Not implemented, but pretend it works if there is nothing
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 49746c8..64fe865 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -25,6 +25,7 @@
#include <linux/proc_ns.h>
#include <linux/file.h>
#include <linux/syscalls.h>
+#include <linux/cgroup.h>
static struct kmem_cache *nsproxy_cachep;
@@ -39,6 +40,9 @@ struct nsproxy init_nsproxy = {
#ifdef CONFIG_NET
.net_ns = &init_net,
#endif
+#ifdef CONFIG_CGROUPS
+ .cgroup_ns = &init_cgroup_ns,
+#endif
};
static inline struct nsproxy *create_nsproxy(void)
@@ -92,6 +96,13 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
goto out_pid;
}
+ new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns,
+ tsk->nsproxy->cgroup_ns);
+ if (IS_ERR(new_nsp->cgroup_ns)) {
+ err = PTR_ERR(new_nsp->cgroup_ns);
+ goto out_cgroup;
+ }
+
new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
if (IS_ERR(new_nsp->net_ns)) {
err = PTR_ERR(new_nsp->net_ns);
@@ -101,6 +112,9 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
return new_nsp;
out_net:
+ if (new_nsp->cgroup_ns)
+ put_cgroup_ns(new_nsp->cgroup_ns);
+out_cgroup:
if (new_nsp->pid_ns_for_children)
put_pid_ns(new_nsp->pid_ns_for_children);
out_pid:
@@ -128,7 +142,8 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
struct nsproxy *new_ns;
if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWPID | CLONE_NEWNET)))) {
+ CLONE_NEWPID | CLONE_NEWNET |
+ CLONE_NEWCGROUP)))) {
get_nsproxy(old_ns);
return 0;
}
@@ -165,6 +180,8 @@ void free_nsproxy(struct nsproxy *ns)
put_ipc_ns(ns->ipc_ns);
if (ns->pid_ns_for_children)
put_pid_ns(ns->pid_ns_for_children);
+ if (ns->cgroup_ns)
+ put_cgroup_ns(ns->cgroup_ns);
put_net(ns->net_ns);
kmem_cache_free(nsproxy_cachep, ns);
}
@@ -180,7 +197,7 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
int err = 0;
if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWNET | CLONE_NEWPID)))
+ CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP)))
return 0;
user_ns = new_cred ? new_cred->user_ns : current_user_ns();
diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index 6415117..4c28523 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -104,7 +104,8 @@ static char *task_group_path(struct task_group *tg)
if (autogroup_path(tg, group_path, PATH_MAX))
return group_path;
- return cgroup_path(tg->css.cgroup, group_path, PATH_MAX);
+ return cgroup_path_ns(tg->css.cgroup, group_path, PATH_MAX,
+ current->nsproxy->cgroup_ns);
}
#endif
--
1.7.9.5
^ permalink raw reply related [flat|nested] 19+ messages in thread
* Re: CGroup Namespaces (v9)
2016-01-05 0:53 ` CGroup Namespaces (v9) Serge E. Hallyn
@ 2016-01-05 19:36 ` Serge E. Hallyn
0 siblings, 0 replies; 19+ messages in thread
From: Serge E. Hallyn @ 2016-01-05 19:36 UTC (permalink / raw)
To: Serge E. Hallyn
Cc: gregkh, linux-api, containers, linux-kernel, ebiederm, lxc-devel,
hannes, tj, cgroups, akpm
On Mon, Jan 04, 2016 at 06:53:08PM -0600, Serge E. Hallyn wrote:
> Ok, please hold off on this, there is another locking question i need to look
> into :(
With my v2 of patch 3 this is resolved, thanks.
^ permalink raw reply [flat|nested] 19+ messages in thread
* [PATCH 3/8 v3] cgroup: introduce cgroup namespaces
2016-01-05 2:07 ` [PATCH 3/8 v2] " Serge E. Hallyn
@ 2016-01-06 2:17 ` Serge E. Hallyn
0 siblings, 0 replies; 19+ messages in thread
From: Serge E. Hallyn @ 2016-01-06 2:17 UTC (permalink / raw)
To: Serge E. Hallyn
Cc: linux-api, containers, hannes, linux-kernel, ebiederm, lxc-devel,
gregkh, tj, cgroups, akpm
Introduce the ability to create new cgroup namespace. The newly created
cgroup namespace remembers the cgroup of the process at the point
of creation of the cgroup namespace (referred as cgroupns-root).
The main purpose of cgroup namespace is to virtualize the contents
of /proc/self/cgroup file. Processes inside a cgroup namespace
are only able to see paths relative to their namespace root
(unless they are moved outside of their cgroupns-root, at which point
they will see a relative path from their cgroupns-root).
For a correctly setup container this enables container-tools
(like libcontainer, lxc, lmctfy, etc.) to create completely virtualized
containers without leaking system level cgroup hierarchy to the task.
This patch only implements the 'unshare' part of the cgroupns.
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
---
Changelog: 2015-11-24
- move cgroup_namespace.c into cgroup.c (and .h)
- reformatting
- make get_cgroup_ns return void
- rename ns->root_cgrps to root_cset.
Changelog: 2015-12-08
- Move init_cgroup_ns to other variable declarations
- Remove accidental conversion of put-css_set to inline
- Drop BUG_ON(NULL)
- Remove unneeded pre declaration of struct cgroupns_operations.
- cgroup.h: collect common ns declerations
Changelog: 2015-12-09
- cgroup.h: move ns declarations to bottom
- cgroup.c: undo all accidental conversions to inline
Changelog: 2015-12-22
- update for new kernfs_path_from_node() return value. Since
cgroup_path was already gpl-exported, I abstained from updating
its return value.
Changelog: 2015-12-23
- cgroup_path(): use init_cgroup_ns when in interupt context.
Changelog: 2015-01-02
- move to_cg_ns definition forward in patch series
- cgroup_release_agent: grab css_set_lock around cgroup_path()
- leave cgroup_path non-namespaced, use cgroup_path_ns when
namespaced path is desired.
Changelog: 2015-01-04
- cgroup_path: continue to use kernfs_path. Since cgroup_path is
non-namespaced, use the old version.
- make cgroup_path_ns_locked() static.
Changelog: 2015-01-05
- don't namespace the path printed in debugfs. It's both improper
and complicates locking.
---
fs/proc/namespaces.c | 3 +
include/linux/cgroup.h | 49 ++++++++++++++
include/linux/nsproxy.h | 2 +
include/linux/proc_ns.h | 4 ++
kernel/cgroup.c | 170 ++++++++++++++++++++++++++++++++++++++++++++++-
kernel/cpuset.c | 3 +-
kernel/fork.c | 2 +-
kernel/nsproxy.c | 21 +++++-
8 files changed, 247 insertions(+), 7 deletions(-)
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index f6e8354..bd61075 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -28,6 +28,9 @@ static const struct proc_ns_operations *ns_entries[] = {
&userns_operations,
#endif
&mntns_operations,
+#ifdef CONFIG_CGROUPS
+ &cgroupns_operations,
+#endif
};
static const char *proc_ns_follow_link(struct dentry *dentry, void **cookie)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 9d70b48..f5fe730 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -17,6 +17,11 @@
#include <linux/seq_file.h>
#include <linux/kernfs.h>
#include <linux/jump_label.h>
+#include <linux/nsproxy.h>
+#include <linux/types.h>
+#include <linux/ns_common.h>
+#include <linux/nsproxy.h>
+#include <linux/user_namespace.h>
#include <linux/cgroup-defs.h>
@@ -570,4 +575,48 @@ static inline int cgroup_init(void) { return 0; }
#endif /* !CONFIG_CGROUPS */
+struct cgroup_namespace {
+ atomic_t count;
+ struct ns_common ns;
+ struct user_namespace *user_ns;
+ struct css_set *root_cset;
+};
+
+extern struct cgroup_namespace init_cgroup_ns;
+
+#ifdef CONFIG_CGROUPS
+
+void free_cgroup_ns(struct cgroup_namespace *ns);
+
+struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns);
+
+char *cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns);
+
+#else /* !CONFIG_CGROUPS */
+
+static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
+static inline struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns)
+{
+ return old_ns;
+}
+
+#endif /* !CONFIG_CGROUPS */
+
+static inline void get_cgroup_ns(struct cgroup_namespace *ns)
+{
+ if (ns)
+ atomic_inc(&ns->count);
+}
+
+static inline void put_cgroup_ns(struct cgroup_namespace *ns)
+{
+ if (ns && atomic_dec_and_test(&ns->count))
+ free_cgroup_ns(ns);
+}
+
#endif /* _LINUX_CGROUP_H */
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 35fa08f..ac0d65b 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -8,6 +8,7 @@ struct mnt_namespace;
struct uts_namespace;
struct ipc_namespace;
struct pid_namespace;
+struct cgroup_namespace;
struct fs_struct;
/*
@@ -33,6 +34,7 @@ struct nsproxy {
struct mnt_namespace *mnt_ns;
struct pid_namespace *pid_ns_for_children;
struct net *net_ns;
+ struct cgroup_namespace *cgroup_ns;
};
extern struct nsproxy init_nsproxy;
diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h
index 42dfc61..de0e771 100644
--- a/include/linux/proc_ns.h
+++ b/include/linux/proc_ns.h
@@ -9,6 +9,8 @@
struct pid_namespace;
struct nsproxy;
struct path;
+struct task_struct;
+struct inode;
struct proc_ns_operations {
const char *name;
@@ -24,6 +26,7 @@ extern const struct proc_ns_operations ipcns_operations;
extern const struct proc_ns_operations pidns_operations;
extern const struct proc_ns_operations userns_operations;
extern const struct proc_ns_operations mntns_operations;
+extern const struct proc_ns_operations cgroupns_operations;
/*
* We always define these enumerators
@@ -34,6 +37,7 @@ enum {
PROC_UTS_INIT_INO = 0xEFFFFFFEU,
PROC_USER_INIT_INO = 0xEFFFFFFDU,
PROC_PID_INIT_INO = 0xEFFFFFFCU,
+ PROC_CGROUP_INIT_INO = 0xEFFFFFFBU,
};
#ifdef CONFIG_PROC_FS
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 6b33631..68b84ba 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -57,6 +57,9 @@
#include <linux/vmalloc.h> /* TODO: replace with more sophisticated array */
#include <linux/kthread.h>
#include <linux/delay.h>
+#include <linux/proc_ns.h>
+#include <linux/nsproxy.h>
+#include <linux/proc_ns.h>
#include <linux/atomic.h>
@@ -208,6 +211,15 @@ static unsigned long have_fork_callback __read_mostly;
static unsigned long have_exit_callback __read_mostly;
static unsigned long have_free_callback __read_mostly;
+/* Cgroup namespace for init task */
+struct cgroup_namespace init_cgroup_ns = {
+ .count = { .counter = 2, },
+ .user_ns = &init_user_ns,
+ .ns.ops = &cgroupns_operations,
+ .ns.inum = PROC_CGROUP_INIT_INO,
+ .root_cset = &init_css_set,
+};
+
/* Ditto for the can_fork callback. */
static unsigned long have_canfork_callback __read_mostly;
@@ -2166,6 +2178,36 @@ static struct file_system_type cgroup2_fs_type = {
.kill_sb = cgroup_kill_sb,
};
+static char *
+cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns)
+{
+ int ret;
+ struct cgroup *root = cset_cgroup_from_root(ns->root_cset, cgrp->root);
+
+ ret = kernfs_path_from_node(cgrp->kn, root->kn, buf, buflen);
+ if (ret < 0 || ret >= buflen)
+ return NULL;
+ return buf;
+}
+
+char *cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns)
+{
+ char *ret;
+
+ mutex_lock(&cgroup_mutex);
+ spin_lock_bh(&css_set_lock);
+
+ ret = cgroup_path_ns_locked(cgrp, buf, buflen, ns);
+
+ spin_unlock_bh(&css_set_lock);
+ mutex_unlock(&cgroup_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(cgroup_path_ns);
+
/**
* task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
* @task: target task
@@ -2193,7 +2235,8 @@ char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
if (root) {
cgrp = task_cgroup_from_root(task, root);
- path = cgroup_path(cgrp, buf, buflen);
+ path = cgroup_path_ns_locked(cgrp, buf, buflen,
+ &init_cgroup_ns);
} else {
/* if no hierarchy exists, everyone is in "/" */
if (strlcpy(buf, "/", buflen) < buflen)
@@ -5272,6 +5315,8 @@ int __init cgroup_init(void)
BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));
+ get_user_ns(init_cgroup_ns.user_ns);
+
mutex_lock(&cgroup_mutex);
/* Add init_css_set to the hash table */
@@ -5409,7 +5454,8 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
* " (deleted)" is appended to the cgroup path.
*/
if (cgroup_on_dfl(cgrp) || !(tsk->flags & PF_EXITING)) {
- path = cgroup_path(cgrp, buf, PATH_MAX);
+ path = cgroup_path_ns_locked(cgrp, buf, PATH_MAX,
+ current->nsproxy->cgroup_ns);
if (!path) {
retval = -ENAMETOOLONG;
goto out_unlock;
@@ -5691,7 +5737,10 @@ static void cgroup_release_agent(struct work_struct *work)
if (!pathbuf || !agentbuf)
goto out;
- path = cgroup_path(cgrp, pathbuf, PATH_MAX);
+ spin_lock_bh(&css_set_lock);
+ path = cgroup_path_ns_locked(cgrp, pathbuf, PATH_MAX,
+ &init_cgroup_ns);
+ spin_unlock_bh(&css_set_lock);
if (!path)
goto out;
@@ -5822,6 +5871,121 @@ struct cgroup *cgroup_get_from_path(const char *path)
}
EXPORT_SYMBOL_GPL(cgroup_get_from_path);
+/* cgroup namespaces */
+
+static struct cgroup_namespace *alloc_cgroup_ns(void)
+{
+ struct cgroup_namespace *new_ns;
+ int ret;
+
+ new_ns = kzalloc(sizeof(struct cgroup_namespace), GFP_KERNEL);
+ if (!new_ns)
+ return ERR_PTR(-ENOMEM);
+ ret = ns_alloc_inum(&new_ns->ns);
+ if (ret) {
+ kfree(new_ns);
+ return ERR_PTR(ret);
+ }
+ atomic_set(&new_ns->count, 1);
+ new_ns->ns.ops = &cgroupns_operations;
+ return new_ns;
+}
+
+void free_cgroup_ns(struct cgroup_namespace *ns)
+{
+ put_css_set(ns->root_cset);
+ put_user_ns(ns->user_ns);
+ ns_free_inum(&ns->ns);
+ kfree(ns);
+}
+EXPORT_SYMBOL(free_cgroup_ns);
+
+struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns)
+{
+ struct cgroup_namespace *new_ns = NULL;
+ struct css_set *cset = NULL;
+ int err;
+
+ BUG_ON(!old_ns);
+
+ if (!(flags & CLONE_NEWCGROUP)) {
+ get_cgroup_ns(old_ns);
+ return old_ns;
+ }
+
+ /* Allow only sysadmin to create cgroup namespace. */
+ err = -EPERM;
+ if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+ goto err_out;
+
+ cset = task_css_set(current);
+ get_css_set(cset);
+
+ err = -ENOMEM;
+ new_ns = alloc_cgroup_ns();
+ if (!new_ns)
+ goto err_out;
+
+ new_ns->user_ns = get_user_ns(user_ns);
+ new_ns->root_cset = cset;
+
+ return new_ns;
+
+err_out:
+ if (cset)
+ put_css_set(cset);
+ kfree(new_ns);
+ return ERR_PTR(err);
+}
+
+static inline struct cgroup_namespace *to_cg_ns(struct ns_common *ns)
+{
+ return container_of(ns, struct cgroup_namespace, ns);
+}
+
+static int cgroupns_install(struct nsproxy *nsproxy, void *ns)
+{
+ pr_info("setns not supported for cgroup namespace");
+ return -EINVAL;
+}
+
+static struct ns_common *cgroupns_get(struct task_struct *task)
+{
+ struct cgroup_namespace *ns = NULL;
+ struct nsproxy *nsproxy;
+
+ task_lock(task);
+ nsproxy = task->nsproxy;
+ if (nsproxy) {
+ ns = nsproxy->cgroup_ns;
+ get_cgroup_ns(ns);
+ }
+ task_unlock(task);
+
+ return ns ? &ns->ns : NULL;
+}
+
+static void cgroupns_put(struct ns_common *ns)
+{
+ put_cgroup_ns(to_cg_ns(ns));
+}
+
+const struct proc_ns_operations cgroupns_operations = {
+ .name = "cgroup",
+ .type = CLONE_NEWCGROUP,
+ .get = cgroupns_get,
+ .put = cgroupns_put,
+ .install = cgroupns_install,
+};
+
+static __init int cgroup_namespaces_init(void)
+{
+ return 0;
+}
+subsys_initcall(cgroup_namespaces_init);
+
#ifdef CONFIG_CGROUP_DEBUG
static struct cgroup_subsys_state *
debug_css_alloc(struct cgroup_subsys_state *parent_css)
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 3e945fc..37c8eb0 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2689,7 +2689,8 @@ int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
retval = -ENAMETOOLONG;
rcu_read_lock();
css = task_css(tsk, cpuset_cgrp_id);
- p = cgroup_path(css->cgroup, buf, PATH_MAX);
+ p = cgroup_path_ns(css->cgroup, buf, PATH_MAX,
+ current->nsproxy->cgroup_ns);
rcu_read_unlock();
if (!p)
goto out_free;
diff --git a/kernel/fork.c b/kernel/fork.c
index ba7d1c0..7982fee 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1880,7 +1880,7 @@ static int check_unshare_flags(unsigned long unshare_flags)
if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET|
- CLONE_NEWUSER|CLONE_NEWPID))
+ CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP))
return -EINVAL;
/*
* Not implemented, but pretend it works if there is nothing
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 49746c8..64fe865 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -25,6 +25,7 @@
#include <linux/proc_ns.h>
#include <linux/file.h>
#include <linux/syscalls.h>
+#include <linux/cgroup.h>
static struct kmem_cache *nsproxy_cachep;
@@ -39,6 +40,9 @@ struct nsproxy init_nsproxy = {
#ifdef CONFIG_NET
.net_ns = &init_net,
#endif
+#ifdef CONFIG_CGROUPS
+ .cgroup_ns = &init_cgroup_ns,
+#endif
};
static inline struct nsproxy *create_nsproxy(void)
@@ -92,6 +96,13 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
goto out_pid;
}
+ new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns,
+ tsk->nsproxy->cgroup_ns);
+ if (IS_ERR(new_nsp->cgroup_ns)) {
+ err = PTR_ERR(new_nsp->cgroup_ns);
+ goto out_cgroup;
+ }
+
new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
if (IS_ERR(new_nsp->net_ns)) {
err = PTR_ERR(new_nsp->net_ns);
@@ -101,6 +112,9 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
return new_nsp;
out_net:
+ if (new_nsp->cgroup_ns)
+ put_cgroup_ns(new_nsp->cgroup_ns);
+out_cgroup:
if (new_nsp->pid_ns_for_children)
put_pid_ns(new_nsp->pid_ns_for_children);
out_pid:
@@ -128,7 +142,8 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
struct nsproxy *new_ns;
if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWPID | CLONE_NEWNET)))) {
+ CLONE_NEWPID | CLONE_NEWNET |
+ CLONE_NEWCGROUP)))) {
get_nsproxy(old_ns);
return 0;
}
@@ -165,6 +180,8 @@ void free_nsproxy(struct nsproxy *ns)
put_ipc_ns(ns->ipc_ns);
if (ns->pid_ns_for_children)
put_pid_ns(ns->pid_ns_for_children);
+ if (ns->cgroup_ns)
+ put_cgroup_ns(ns->cgroup_ns);
put_net(ns->net_ns);
kmem_cache_free(nsproxy_cachep, ns);
}
@@ -180,7 +197,7 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
int err = 0;
if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWNET | CLONE_NEWPID)))
+ CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP)))
return 0;
user_ns = new_cred ? new_cred->user_ns : current_user_ns();
--
1.7.9.5
^ permalink raw reply related [flat|nested] 19+ messages in thread
* [PATCH 3/8] cgroup: introduce cgroup namespaces
2016-01-29 8:54 CGroup Namespaces (v10) serge.hallyn
@ 2016-01-29 8:54 ` serge.hallyn
0 siblings, 0 replies; 19+ messages in thread
From: serge.hallyn @ 2016-01-29 8:54 UTC (permalink / raw)
To: linux-kernel
Cc: adityakali, tj, linux-api, containers, cgroups, lxc-devel, akpm,
ebiederm, gregkh, lizefan, hannes, Serge Hallyn
From: Aditya Kali <adityakali@google.com>
Introduce the ability to create new cgroup namespace. The newly created
cgroup namespace remembers the cgroup of the process at the point
of creation of the cgroup namespace (referred as cgroupns-root).
The main purpose of cgroup namespace is to virtualize the contents
of /proc/self/cgroup file. Processes inside a cgroup namespace
are only able to see paths relative to their namespace root
(unless they are moved outside of their cgroupns-root, at which point
they will see a relative path from their cgroupns-root).
For a correctly setup container this enables container-tools
(like libcontainer, lxc, lmctfy, etc.) to create completely virtualized
containers without leaking system level cgroup hierarchy to the task.
This patch only implements the 'unshare' part of the cgroupns.
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
---
Changelog: 2015-11-24
- move cgroup_namespace.c into cgroup.c (and .h)
- reformatting
- make get_cgroup_ns return void
- rename ns->root_cgrps to root_cset.
Changelog: 2015-12-08
- Move init_cgroup_ns to other variable declarations
- Remove accidental conversion of put-css_set to inline
- Drop BUG_ON(NULL)
- Remove unneeded pre declaration of struct cgroupns_operations.
- cgroup.h: collect common ns declerations
Changelog: 2015-12-09
- cgroup.h: move ns declarations to bottom
- cgroup.c: undo all accidental conversions to inline
Changelog: 2015-12-22
- update for new kernfs_path_from_node() return value. Since
cgroup_path was already gpl-exported, I abstained from updating
its return value.
Changelog: 2015-12-23
- cgroup_path(): use init_cgroup_ns when in interupt context.
Changelog: 2015-01-02
- move to_cg_ns definition forward in patch series
- cgroup_release_agent: grab css_set_lock around cgroup_path()
- leave cgroup_path non-namespaced, use cgroup_path_ns when
namespaced path is desired.
Changelog: 2015-01-04
- cgroup_path: continue to use kernfs_path. Since cgroup_path is
non-namespaced, use the old version.
- make cgroup_path_ns_locked() static.
Changelog: 2015-01-05
- don't namespace the path printed in debugfs.
Changelog: 2015-01-27
- remove unneeded NULL check before put_cgroup_ns()
Changelog: 2015-01-28
- lock around task_css_set in copy_cgroup_ns, and don't
take rcu lock arounc copy_cgroup_ns call in cpuset.
---
fs/proc/namespaces.c | 3 +
include/linux/cgroup.h | 49 +++++++++++++
include/linux/nsproxy.h | 2 +
include/linux/proc_ns.h | 4 ++
kernel/cgroup.c | 176 ++++++++++++++++++++++++++++++++++++++++++++++-
kernel/cpuset.c | 8 +--
kernel/fork.c | 2 +-
kernel/nsproxy.c | 19 ++++-
8 files changed, 253 insertions(+), 10 deletions(-)
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index 276f124..72cb26f 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -28,6 +28,9 @@ static const struct proc_ns_operations *ns_entries[] = {
&userns_operations,
#endif
&mntns_operations,
+#ifdef CONFIG_CGROUPS
+ &cgroupns_operations,
+#endif
};
static const char *proc_ns_get_link(struct dentry *dentry,
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 2162dca..1773af0 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -17,6 +17,11 @@
#include <linux/seq_file.h>
#include <linux/kernfs.h>
#include <linux/jump_label.h>
+#include <linux/nsproxy.h>
+#include <linux/types.h>
+#include <linux/ns_common.h>
+#include <linux/nsproxy.h>
+#include <linux/user_namespace.h>
#include <linux/cgroup-defs.h>
@@ -611,4 +616,48 @@ static inline void cgroup_sk_free(struct sock_cgroup_data *skcd) {}
#endif /* CONFIG_CGROUP_DATA */
+struct cgroup_namespace {
+ atomic_t count;
+ struct ns_common ns;
+ struct user_namespace *user_ns;
+ struct css_set *root_cset;
+};
+
+extern struct cgroup_namespace init_cgroup_ns;
+
+#ifdef CONFIG_CGROUPS
+
+void free_cgroup_ns(struct cgroup_namespace *ns);
+
+struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns);
+
+char *cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns);
+
+#else /* !CONFIG_CGROUPS */
+
+static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
+static inline struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns)
+{
+ return old_ns;
+}
+
+#endif /* !CONFIG_CGROUPS */
+
+static inline void get_cgroup_ns(struct cgroup_namespace *ns)
+{
+ if (ns)
+ atomic_inc(&ns->count);
+}
+
+static inline void put_cgroup_ns(struct cgroup_namespace *ns)
+{
+ if (ns && atomic_dec_and_test(&ns->count))
+ free_cgroup_ns(ns);
+}
+
#endif /* _LINUX_CGROUP_H */
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 35fa08f..ac0d65b 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -8,6 +8,7 @@ struct mnt_namespace;
struct uts_namespace;
struct ipc_namespace;
struct pid_namespace;
+struct cgroup_namespace;
struct fs_struct;
/*
@@ -33,6 +34,7 @@ struct nsproxy {
struct mnt_namespace *mnt_ns;
struct pid_namespace *pid_ns_for_children;
struct net *net_ns;
+ struct cgroup_namespace *cgroup_ns;
};
extern struct nsproxy init_nsproxy;
diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h
index 42dfc61..de0e771 100644
--- a/include/linux/proc_ns.h
+++ b/include/linux/proc_ns.h
@@ -9,6 +9,8 @@
struct pid_namespace;
struct nsproxy;
struct path;
+struct task_struct;
+struct inode;
struct proc_ns_operations {
const char *name;
@@ -24,6 +26,7 @@ extern const struct proc_ns_operations ipcns_operations;
extern const struct proc_ns_operations pidns_operations;
extern const struct proc_ns_operations userns_operations;
extern const struct proc_ns_operations mntns_operations;
+extern const struct proc_ns_operations cgroupns_operations;
/*
* We always define these enumerators
@@ -34,6 +37,7 @@ enum {
PROC_UTS_INIT_INO = 0xEFFFFFFEU,
PROC_USER_INIT_INO = 0xEFFFFFFDU,
PROC_PID_INIT_INO = 0xEFFFFFFCU,
+ PROC_CGROUP_INIT_INO = 0xEFFFFFFBU,
};
#ifdef CONFIG_PROC_FS
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index c03a640..d828e1f 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -58,6 +58,9 @@
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/atomic.h>
+#include <linux/proc_ns.h>
+#include <linux/nsproxy.h>
+#include <linux/proc_ns.h>
#include <net/sock.h>
/*
@@ -208,6 +211,15 @@ static unsigned long have_fork_callback __read_mostly;
static unsigned long have_exit_callback __read_mostly;
static unsigned long have_free_callback __read_mostly;
+/* Cgroup namespace for init task */
+struct cgroup_namespace init_cgroup_ns = {
+ .count = { .counter = 2, },
+ .user_ns = &init_user_ns,
+ .ns.ops = &cgroupns_operations,
+ .ns.inum = PROC_CGROUP_INIT_INO,
+ .root_cset = &init_css_set,
+};
+
/* Ditto for the can_fork callback. */
static unsigned long have_canfork_callback __read_mostly;
@@ -2166,6 +2178,36 @@ static struct file_system_type cgroup2_fs_type = {
.kill_sb = cgroup_kill_sb,
};
+static char *
+cgroup_path_ns_locked(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns)
+{
+ int ret;
+ struct cgroup *root = cset_cgroup_from_root(ns->root_cset, cgrp->root);
+
+ ret = kernfs_path_from_node(cgrp->kn, root->kn, buf, buflen);
+ if (ret < 0 || ret >= buflen)
+ return NULL;
+ return buf;
+}
+
+char *cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns)
+{
+ char *ret;
+
+ mutex_lock(&cgroup_mutex);
+ spin_lock_bh(&css_set_lock);
+
+ ret = cgroup_path_ns_locked(cgrp, buf, buflen, ns);
+
+ spin_unlock_bh(&css_set_lock);
+ mutex_unlock(&cgroup_mutex);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(cgroup_path_ns);
+
/**
* task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
* @task: target task
@@ -2193,7 +2235,8 @@ char *task_cgroup_path(struct task_struct *task, char *buf, size_t buflen)
if (root) {
cgrp = task_cgroup_from_root(task, root);
- path = cgroup_path(cgrp, buf, buflen);
+ path = cgroup_path_ns_locked(cgrp, buf, buflen,
+ &init_cgroup_ns);
} else {
/* if no hierarchy exists, everyone is in "/" */
if (strlcpy(buf, "/", buflen) < buflen)
@@ -5272,6 +5315,8 @@ int __init cgroup_init(void)
BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));
+ get_user_ns(init_cgroup_ns.user_ns);
+
mutex_lock(&cgroup_mutex);
/* Add init_css_set to the hash table */
@@ -5409,7 +5454,8 @@ int proc_cgroup_show(struct seq_file *m, struct pid_namespace *ns,
* " (deleted)" is appended to the cgroup path.
*/
if (cgroup_on_dfl(cgrp) || !(tsk->flags & PF_EXITING)) {
- path = cgroup_path(cgrp, buf, PATH_MAX);
+ path = cgroup_path_ns_locked(cgrp, buf, PATH_MAX,
+ current->nsproxy->cgroup_ns);
if (!path) {
retval = -ENAMETOOLONG;
goto out_unlock;
@@ -5691,7 +5737,10 @@ static void cgroup_release_agent(struct work_struct *work)
if (!pathbuf || !agentbuf)
goto out;
- path = cgroup_path(cgrp, pathbuf, PATH_MAX);
+ spin_lock_bh(&css_set_lock);
+ path = cgroup_path_ns_locked(cgrp, pathbuf, PATH_MAX,
+ &init_cgroup_ns);
+ spin_unlock_bh(&css_set_lock);
if (!path)
goto out;
@@ -5875,6 +5924,127 @@ void cgroup_sk_free(struct sock_cgroup_data *skcd)
#endif /* CONFIG_SOCK_CGROUP_DATA */
+/* cgroup namespaces */
+
+static struct cgroup_namespace *alloc_cgroup_ns(void)
+{
+ struct cgroup_namespace *new_ns;
+ int ret;
+
+ new_ns = kzalloc(sizeof(struct cgroup_namespace), GFP_KERNEL);
+ if (!new_ns)
+ return ERR_PTR(-ENOMEM);
+ ret = ns_alloc_inum(&new_ns->ns);
+ if (ret) {
+ kfree(new_ns);
+ return ERR_PTR(ret);
+ }
+ atomic_set(&new_ns->count, 1);
+ new_ns->ns.ops = &cgroupns_operations;
+ return new_ns;
+}
+
+void free_cgroup_ns(struct cgroup_namespace *ns)
+{
+ put_css_set(ns->root_cset);
+ put_user_ns(ns->user_ns);
+ ns_free_inum(&ns->ns);
+ kfree(ns);
+}
+EXPORT_SYMBOL(free_cgroup_ns);
+
+struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns)
+{
+ struct cgroup_namespace *new_ns = NULL;
+ struct css_set *cset = NULL;
+ int err;
+
+ BUG_ON(!old_ns);
+
+ if (!(flags & CLONE_NEWCGROUP)) {
+ get_cgroup_ns(old_ns);
+ return old_ns;
+ }
+
+ /* Allow only sysadmin to create cgroup namespace. */
+ err = -EPERM;
+ if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+ goto err_out;
+
+ mutex_lock(&cgroup_mutex);
+ spin_lock_bh(&css_set_lock);
+
+ cset = task_css_set(current);
+ get_css_set(cset);
+
+ spin_unlock_bh(&css_set_lock);
+ mutex_unlock(&cgroup_mutex);
+
+ err = -ENOMEM;
+ new_ns = alloc_cgroup_ns();
+ if (!new_ns)
+ goto err_out;
+
+ new_ns->user_ns = get_user_ns(user_ns);
+ new_ns->root_cset = cset;
+
+ return new_ns;
+
+err_out:
+ if (cset)
+ put_css_set(cset);
+ kfree(new_ns);
+ return ERR_PTR(err);
+}
+
+static inline struct cgroup_namespace *to_cg_ns(struct ns_common *ns)
+{
+ return container_of(ns, struct cgroup_namespace, ns);
+}
+
+static int cgroupns_install(struct nsproxy *nsproxy, void *ns)
+{
+ pr_info("setns not supported for cgroup namespace");
+ return -EINVAL;
+}
+
+static struct ns_common *cgroupns_get(struct task_struct *task)
+{
+ struct cgroup_namespace *ns = NULL;
+ struct nsproxy *nsproxy;
+
+ task_lock(task);
+ nsproxy = task->nsproxy;
+ if (nsproxy) {
+ ns = nsproxy->cgroup_ns;
+ get_cgroup_ns(ns);
+ }
+ task_unlock(task);
+
+ return ns ? &ns->ns : NULL;
+}
+
+static void cgroupns_put(struct ns_common *ns)
+{
+ put_cgroup_ns(to_cg_ns(ns));
+}
+
+const struct proc_ns_operations cgroupns_operations = {
+ .name = "cgroup",
+ .type = CLONE_NEWCGROUP,
+ .get = cgroupns_get,
+ .put = cgroupns_put,
+ .install = cgroupns_install,
+};
+
+static __init int cgroup_namespaces_init(void)
+{
+ return 0;
+}
+subsys_initcall(cgroup_namespaces_init);
+
#ifdef CONFIG_CGROUP_DEBUG
static struct cgroup_subsys_state *
debug_css_alloc(struct cgroup_subsys_state *parent_css)
diff --git a/kernel/cpuset.c b/kernel/cpuset.c
index 3e945fc..62d6108 100644
--- a/kernel/cpuset.c
+++ b/kernel/cpuset.c
@@ -2687,10 +2687,10 @@ int proc_cpuset_show(struct seq_file *m, struct pid_namespace *ns,
goto out;
retval = -ENAMETOOLONG;
- rcu_read_lock();
- css = task_css(tsk, cpuset_cgrp_id);
- p = cgroup_path(css->cgroup, buf, PATH_MAX);
- rcu_read_unlock();
+ css = task_get_css(tsk, cpuset_cgrp_id);
+ p = cgroup_path_ns(css->cgroup, buf, PATH_MAX,
+ current->nsproxy->cgroup_ns);
+ css_put(css);
if (!p)
goto out_free;
seq_puts(m, p);
diff --git a/kernel/fork.c b/kernel/fork.c
index 2e391c7..6611a62 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1884,7 +1884,7 @@ static int check_unshare_flags(unsigned long unshare_flags)
if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET|
- CLONE_NEWUSER|CLONE_NEWPID))
+ CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP))
return -EINVAL;
/*
* Not implemented, but pretend it works if there is nothing
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 49746c8..782102e 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -25,6 +25,7 @@
#include <linux/proc_ns.h>
#include <linux/file.h>
#include <linux/syscalls.h>
+#include <linux/cgroup.h>
static struct kmem_cache *nsproxy_cachep;
@@ -39,6 +40,9 @@ struct nsproxy init_nsproxy = {
#ifdef CONFIG_NET
.net_ns = &init_net,
#endif
+#ifdef CONFIG_CGROUPS
+ .cgroup_ns = &init_cgroup_ns,
+#endif
};
static inline struct nsproxy *create_nsproxy(void)
@@ -92,6 +96,13 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
goto out_pid;
}
+ new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns,
+ tsk->nsproxy->cgroup_ns);
+ if (IS_ERR(new_nsp->cgroup_ns)) {
+ err = PTR_ERR(new_nsp->cgroup_ns);
+ goto out_cgroup;
+ }
+
new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
if (IS_ERR(new_nsp->net_ns)) {
err = PTR_ERR(new_nsp->net_ns);
@@ -101,6 +112,8 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
return new_nsp;
out_net:
+ put_cgroup_ns(new_nsp->cgroup_ns);
+out_cgroup:
if (new_nsp->pid_ns_for_children)
put_pid_ns(new_nsp->pid_ns_for_children);
out_pid:
@@ -128,7 +141,8 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
struct nsproxy *new_ns;
if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWPID | CLONE_NEWNET)))) {
+ CLONE_NEWPID | CLONE_NEWNET |
+ CLONE_NEWCGROUP)))) {
get_nsproxy(old_ns);
return 0;
}
@@ -165,6 +179,7 @@ void free_nsproxy(struct nsproxy *ns)
put_ipc_ns(ns->ipc_ns);
if (ns->pid_ns_for_children)
put_pid_ns(ns->pid_ns_for_children);
+ put_cgroup_ns(ns->cgroup_ns);
put_net(ns->net_ns);
kmem_cache_free(nsproxy_cachep, ns);
}
@@ -180,7 +195,7 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
int err = 0;
if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWNET | CLONE_NEWPID)))
+ CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP)))
return 0;
user_ns = new_cred ? new_cred->user_ns : current_user_ns();
--
1.7.9.5
^ permalink raw reply related [flat|nested] 19+ messages in thread
* Re: [PATCH 3/8] cgroup: introduce cgroup namespaces
2015-12-23 4:23 ` [PATCH 3/8] cgroup: introduce cgroup namespaces serge.hallyn
@ 2015-12-23 16:15 ` Tejun Heo
0 siblings, 0 replies; 19+ messages in thread
From: Tejun Heo @ 2015-12-23 16:15 UTC (permalink / raw)
To: serge.hallyn
Cc: linux-kernel, adityakali, linux-api, containers, cgroups,
lxc-devel, akpm, ebiederm, gregkh, lizefan, hannes, Serge Hallyn
Hello,
On Tue, Dec 22, 2015 at 10:23:24PM -0600, serge.hallyn@ubuntu.com wrote:
...
> +char *cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen)
> +{
> + int ret;
> +
> + ret = cgroup_path_ns(cgrp, buf, buflen, current->nsproxy->cgroup_ns);
> + if (ret < 0 || ret >= buflen)
> + return NULL;
> + return buf;
> +}
> +EXPORT_SYMBOL_GPL(cgroup_path);
Shouldn't this function check whether it's being called from a task
context? e.g. it could be being called from an irq handler and may
end up scoping the path incorrectly.
Thanks.
--
tejun
^ permalink raw reply [flat|nested] 19+ messages in thread
* [PATCH 3/8] cgroup: introduce cgroup namespaces
2015-12-23 4:23 CGroup Namespaces (v8) serge.hallyn
@ 2015-12-23 4:23 ` serge.hallyn
2015-12-23 16:15 ` Tejun Heo
0 siblings, 1 reply; 19+ messages in thread
From: serge.hallyn @ 2015-12-23 4:23 UTC (permalink / raw)
To: linux-kernel
Cc: adityakali, tj, linux-api, containers, cgroups, lxc-devel, akpm,
ebiederm, gregkh, lizefan, hannes, Serge Hallyn
From: Aditya Kali <adityakali@google.com>
Introduce the ability to create new cgroup namespace. The newly created
cgroup namespace remembers the cgroup of the process at the point
of creation of the cgroup namespace (referred as cgroupns-root).
The main purpose of cgroup namespace is to virtualize the contents
of /proc/self/cgroup file. Processes inside a cgroup namespace
are only able to see paths relative to their namespace root
(unless they are moved outside of their cgroupns-root, at which point
they will see a relative path from their cgroupns-root).
For a correctly setup container this enables container-tools
(like libcontainer, lxc, lmctfy, etc.) to create completely virtualized
containers without leaking system level cgroup hierarchy to the task.
This patch only implements the 'unshare' part of the cgroupns.
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
---
Changelog: 2015-11-24
- move cgroup_namespace.c into cgroup.c (and .h)
- reformatting
- make get_cgroup_ns return void
- rename ns->root_cgrps to root_cset.
Changelog: 2015-12-08
- Move init_cgroup_ns to other variable declarations
- Remove accidental conversion of put-css_set to inline
- Drop BUG_ON(NULL)
- Remove unneeded pre declaration of struct cgroupns_operations.
- cgroup.h: collect common ns declerations
Changelog: 2015-12-09
- cgroup.h: move ns declarations to bottom
- cgroup.c: undo all accidental conversions to inline
Changelog: 2015-12-22
- update for new kernfs_path_from_node() return value. Since
cgroup_path was already gpl-exported, I abstained from updating
its return value.
---
fs/proc/namespaces.c | 3 +
include/linux/cgroup.h | 54 ++++++++++++++++--
include/linux/nsproxy.h | 2 +
include/linux/proc_ns.h | 4 ++
kernel/cgroup.c | 144 +++++++++++++++++++++++++++++++++++++++++++++++
kernel/fork.c | 2 +-
kernel/nsproxy.c | 21 ++++++-
7 files changed, 221 insertions(+), 9 deletions(-)
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index f6e8354..bd61075 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -28,6 +28,9 @@ static const struct proc_ns_operations *ns_entries[] = {
&userns_operations,
#endif
&mntns_operations,
+#ifdef CONFIG_CGROUPS
+ &cgroupns_operations,
+#endif
};
static const char *proc_ns_follow_link(struct dentry *dentry, void **cookie)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 9d70b48..6d0992f 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -17,6 +17,11 @@
#include <linux/seq_file.h>
#include <linux/kernfs.h>
#include <linux/jump_label.h>
+#include <linux/nsproxy.h>
+#include <linux/types.h>
+#include <linux/ns_common.h>
+#include <linux/nsproxy.h>
+#include <linux/user_namespace.h>
#include <linux/cgroup-defs.h>
@@ -532,12 +537,6 @@ static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen)
return kernfs_name(cgrp->kn, buf, buflen);
}
-static inline char * __must_check cgroup_path(struct cgroup *cgrp, char *buf,
- size_t buflen)
-{
- return kernfs_path(cgrp->kn, buf, buflen);
-}
-
static inline void pr_cont_cgroup_name(struct cgroup *cgrp)
{
pr_cont_kernfs_name(cgrp->kn);
@@ -570,4 +569,47 @@ static inline int cgroup_init(void) { return 0; }
#endif /* !CONFIG_CGROUPS */
+struct cgroup_namespace {
+ atomic_t count;
+ struct ns_common ns;
+ struct user_namespace *user_ns;
+ struct css_set *root_cset;
+};
+
+extern struct cgroup_namespace init_cgroup_ns;
+
+#ifdef CONFIG_CGROUPS
+
+void free_cgroup_ns(struct cgroup_namespace *ns);
+
+struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns);
+
+char *cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen);
+
+#else /* !CONFIG_CGROUPS */
+
+static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
+static inline struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns)
+{
+ return old_ns;
+}
+
+#endif /* !CONFIG_CGROUPS */
+
+static inline void get_cgroup_ns(struct cgroup_namespace *ns)
+{
+ if (ns)
+ atomic_inc(&ns->count);
+}
+
+static inline void put_cgroup_ns(struct cgroup_namespace *ns)
+{
+ if (ns && atomic_dec_and_test(&ns->count))
+ free_cgroup_ns(ns);
+}
+
#endif /* _LINUX_CGROUP_H */
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 35fa08f..ac0d65b 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -8,6 +8,7 @@ struct mnt_namespace;
struct uts_namespace;
struct ipc_namespace;
struct pid_namespace;
+struct cgroup_namespace;
struct fs_struct;
/*
@@ -33,6 +34,7 @@ struct nsproxy {
struct mnt_namespace *mnt_ns;
struct pid_namespace *pid_ns_for_children;
struct net *net_ns;
+ struct cgroup_namespace *cgroup_ns;
};
extern struct nsproxy init_nsproxy;
diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h
index 42dfc61..de0e771 100644
--- a/include/linux/proc_ns.h
+++ b/include/linux/proc_ns.h
@@ -9,6 +9,8 @@
struct pid_namespace;
struct nsproxy;
struct path;
+struct task_struct;
+struct inode;
struct proc_ns_operations {
const char *name;
@@ -24,6 +26,7 @@ extern const struct proc_ns_operations ipcns_operations;
extern const struct proc_ns_operations pidns_operations;
extern const struct proc_ns_operations userns_operations;
extern const struct proc_ns_operations mntns_operations;
+extern const struct proc_ns_operations cgroupns_operations;
/*
* We always define these enumerators
@@ -34,6 +37,7 @@ enum {
PROC_UTS_INIT_INO = 0xEFFFFFFEU,
PROC_USER_INIT_INO = 0xEFFFFFFDU,
PROC_PID_INIT_INO = 0xEFFFFFFCU,
+ PROC_CGROUP_INIT_INO = 0xEFFFFFFBU,
};
#ifdef CONFIG_PROC_FS
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 6b33631..72336f5 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -57,6 +57,9 @@
#include <linux/vmalloc.h> /* TODO: replace with more sophisticated array */
#include <linux/kthread.h>
#include <linux/delay.h>
+#include <linux/proc_ns.h>
+#include <linux/nsproxy.h>
+#include <linux/proc_ns.h>
#include <linux/atomic.h>
@@ -208,6 +211,15 @@ static unsigned long have_fork_callback __read_mostly;
static unsigned long have_exit_callback __read_mostly;
static unsigned long have_free_callback __read_mostly;
+/* Cgroup namespace for init task */
+struct cgroup_namespace init_cgroup_ns = {
+ .count = { .counter = 1, },
+ .user_ns = &init_user_ns,
+ .ns.ops = &cgroupns_operations,
+ .ns.inum = PROC_CGROUP_INIT_INO,
+ .root_cset = &init_css_set,
+};
+
/* Ditto for the can_fork callback. */
static unsigned long have_canfork_callback __read_mostly;
@@ -2166,6 +2178,26 @@ static struct file_system_type cgroup2_fs_type = {
.kill_sb = cgroup_kill_sb,
};
+static int cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns)
+{
+ struct cgroup *root;
+
+ root = cset_cgroup_from_root(ns->root_cset, cgrp->root);
+ return kernfs_path_from_node(cgrp->kn, root->kn, buf, buflen);
+}
+
+char *cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen)
+{
+ int ret;
+
+ ret = cgroup_path_ns(cgrp, buf, buflen, current->nsproxy->cgroup_ns);
+ if (ret < 0 || ret >= buflen)
+ return NULL;
+ return buf;
+}
+EXPORT_SYMBOL_GPL(cgroup_path);
+
/**
* task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
* @task: target task
@@ -5272,6 +5304,8 @@ int __init cgroup_init(void)
BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));
+ get_user_ns(init_cgroup_ns.user_ns);
+
mutex_lock(&cgroup_mutex);
/* Add init_css_set to the hash table */
@@ -5822,6 +5856,116 @@ struct cgroup *cgroup_get_from_path(const char *path)
}
EXPORT_SYMBOL_GPL(cgroup_get_from_path);
+/* cgroup namespaces */
+
+static struct cgroup_namespace *alloc_cgroup_ns(void)
+{
+ struct cgroup_namespace *new_ns;
+ int ret;
+
+ new_ns = kzalloc(sizeof(struct cgroup_namespace), GFP_KERNEL);
+ if (!new_ns)
+ return ERR_PTR(-ENOMEM);
+ ret = ns_alloc_inum(&new_ns->ns);
+ if (ret) {
+ kfree(new_ns);
+ return ERR_PTR(ret);
+ }
+ atomic_set(&new_ns->count, 1);
+ new_ns->ns.ops = &cgroupns_operations;
+ return new_ns;
+}
+
+void free_cgroup_ns(struct cgroup_namespace *ns)
+{
+ put_css_set(ns->root_cset);
+ put_user_ns(ns->user_ns);
+ ns_free_inum(&ns->ns);
+ kfree(ns);
+}
+EXPORT_SYMBOL(free_cgroup_ns);
+
+struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns)
+{
+ struct cgroup_namespace *new_ns = NULL;
+ struct css_set *cset = NULL;
+ int err;
+
+ BUG_ON(!old_ns);
+
+ if (!(flags & CLONE_NEWCGROUP)) {
+ get_cgroup_ns(old_ns);
+ return old_ns;
+ }
+
+ /* Allow only sysadmin to create cgroup namespace. */
+ err = -EPERM;
+ if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+ goto err_out;
+
+ cset = task_css_set(current);
+ get_css_set(cset);
+
+ err = -ENOMEM;
+ new_ns = alloc_cgroup_ns();
+ if (!new_ns)
+ goto err_out;
+
+ new_ns->user_ns = get_user_ns(user_ns);
+ new_ns->root_cset = cset;
+
+ return new_ns;
+
+err_out:
+ if (cset)
+ put_css_set(cset);
+ kfree(new_ns);
+ return ERR_PTR(err);
+}
+
+static int cgroupns_install(struct nsproxy *nsproxy, void *ns)
+{
+ pr_info("setns not supported for cgroup namespace");
+ return -EINVAL;
+}
+
+static struct ns_common *cgroupns_get(struct task_struct *task)
+{
+ struct cgroup_namespace *ns = NULL;
+ struct nsproxy *nsproxy;
+
+ task_lock(task);
+ nsproxy = task->nsproxy;
+ if (nsproxy) {
+ ns = nsproxy->cgroup_ns;
+ get_cgroup_ns(ns);
+ }
+ task_unlock(task);
+
+ return ns ? &ns->ns : NULL;
+}
+
+static void cgroupns_put(struct ns_common *ns)
+{
+ put_cgroup_ns(to_cg_ns(ns));
+}
+
+const struct proc_ns_operations cgroupns_operations = {
+ .name = "cgroup",
+ .type = CLONE_NEWCGROUP,
+ .get = cgroupns_get,
+ .put = cgroupns_put,
+ .install = cgroupns_install,
+};
+
+static __init int cgroup_namespaces_init(void)
+{
+ return 0;
+}
+subsys_initcall(cgroup_namespaces_init);
+
#ifdef CONFIG_CGROUP_DEBUG
static struct cgroup_subsys_state *
debug_css_alloc(struct cgroup_subsys_state *parent_css)
diff --git a/kernel/fork.c b/kernel/fork.c
index ba7d1c0..7982fee 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1880,7 +1880,7 @@ static int check_unshare_flags(unsigned long unshare_flags)
if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET|
- CLONE_NEWUSER|CLONE_NEWPID))
+ CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP))
return -EINVAL;
/*
* Not implemented, but pretend it works if there is nothing
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 49746c8..64fe865 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -25,6 +25,7 @@
#include <linux/proc_ns.h>
#include <linux/file.h>
#include <linux/syscalls.h>
+#include <linux/cgroup.h>
static struct kmem_cache *nsproxy_cachep;
@@ -39,6 +40,9 @@ struct nsproxy init_nsproxy = {
#ifdef CONFIG_NET
.net_ns = &init_net,
#endif
+#ifdef CONFIG_CGROUPS
+ .cgroup_ns = &init_cgroup_ns,
+#endif
};
static inline struct nsproxy *create_nsproxy(void)
@@ -92,6 +96,13 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
goto out_pid;
}
+ new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns,
+ tsk->nsproxy->cgroup_ns);
+ if (IS_ERR(new_nsp->cgroup_ns)) {
+ err = PTR_ERR(new_nsp->cgroup_ns);
+ goto out_cgroup;
+ }
+
new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
if (IS_ERR(new_nsp->net_ns)) {
err = PTR_ERR(new_nsp->net_ns);
@@ -101,6 +112,9 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
return new_nsp;
out_net:
+ if (new_nsp->cgroup_ns)
+ put_cgroup_ns(new_nsp->cgroup_ns);
+out_cgroup:
if (new_nsp->pid_ns_for_children)
put_pid_ns(new_nsp->pid_ns_for_children);
out_pid:
@@ -128,7 +142,8 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
struct nsproxy *new_ns;
if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWPID | CLONE_NEWNET)))) {
+ CLONE_NEWPID | CLONE_NEWNET |
+ CLONE_NEWCGROUP)))) {
get_nsproxy(old_ns);
return 0;
}
@@ -165,6 +180,8 @@ void free_nsproxy(struct nsproxy *ns)
put_ipc_ns(ns->ipc_ns);
if (ns->pid_ns_for_children)
put_pid_ns(ns->pid_ns_for_children);
+ if (ns->cgroup_ns)
+ put_cgroup_ns(ns->cgroup_ns);
put_net(ns->net_ns);
kmem_cache_free(nsproxy_cachep, ns);
}
@@ -180,7 +197,7 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
int err = 0;
if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWNET | CLONE_NEWPID)))
+ CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP)))
return 0;
user_ns = new_cred ? new_cred->user_ns : current_user_ns();
--
1.7.9.5
^ permalink raw reply related [flat|nested] 19+ messages in thread
* [PATCH 3/8] cgroup: introduce cgroup namespaces
2015-12-09 19:28 CGroup Namespaces (v7) serge.hallyn
@ 2015-12-09 19:28 ` serge.hallyn
0 siblings, 0 replies; 19+ messages in thread
From: serge.hallyn @ 2015-12-09 19:28 UTC (permalink / raw)
To: linux-kernel
Cc: adityakali, tj, linux-api, containers, cgroups, lxc-devel, akpm,
ebiederm, gregkh, lizefan, hannes, Serge Hallyn
From: Aditya Kali <adityakali@google.com>
Introduce the ability to create new cgroup namespace. The newly created
cgroup namespace remembers the cgroup of the process at the point
of creation of the cgroup namespace (referred as cgroupns-root).
The main purpose of cgroup namespace is to virtualize the contents
of /proc/self/cgroup file. Processes inside a cgroup namespace
are only able to see paths relative to their namespace root
(unless they are moved outside of their cgroupns-root, at which point
they will see a relative path from their cgroupns-root).
For a correctly setup container this enables container-tools
(like libcontainer, lxc, lmctfy, etc.) to create completely virtualized
containers without leaking system level cgroup hierarchy to the task.
This patch only implements the 'unshare' part of the cgroupns.
Signed-off-by: Aditya Kali <adityakali@google.com>
Signed-off-by: Serge Hallyn <serge.hallyn@canonical.com>
---
Changelog: 2015-11-24
- move cgroup_namespace.c into cgroup.c (and .h)
- reformatting
- make get_cgroup_ns return void
- rename ns->root_cgrps to root_cset.
Changelog: 2015-12-08
- Move init_cgroup_ns to other variable declarations
- Remove accidental conversion of put-css_set to inline
- Drop BUG_ON(NULL)
- Remove unneeded pre declaration of struct cgroupns_operations.
- cgroup.h: collect common ns declerations
---
fs/proc/namespaces.c | 3 +
include/linux/cgroup.h | 54 ++++++++++++++++--
include/linux/nsproxy.h | 2 +
include/linux/proc_ns.h | 4 ++
kernel/cgroup.c | 146 ++++++++++++++++++++++++++++++++++++++++++++++-
kernel/fork.c | 2 +-
kernel/nsproxy.c | 21 ++++++-
7 files changed, 220 insertions(+), 12 deletions(-)
diff --git a/fs/proc/namespaces.c b/fs/proc/namespaces.c
index f6e8354..bd61075 100644
--- a/fs/proc/namespaces.c
+++ b/fs/proc/namespaces.c
@@ -28,6 +28,9 @@ static const struct proc_ns_operations *ns_entries[] = {
&userns_operations,
#endif
&mntns_operations,
+#ifdef CONFIG_CGROUPS
+ &cgroupns_operations,
+#endif
};
static const char *proc_ns_follow_link(struct dentry *dentry, void **cookie)
diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h
index 2b3e2314..906e348 100644
--- a/include/linux/cgroup.h
+++ b/include/linux/cgroup.h
@@ -17,9 +17,57 @@
#include <linux/seq_file.h>
#include <linux/kernfs.h>
#include <linux/jump_label.h>
+#include <linux/nsproxy.h>
+#include <linux/types.h>
+#include <linux/ns_common.h>
+#include <linux/nsproxy.h>
+#include <linux/user_namespace.h>
#include <linux/cgroup-defs.h>
+struct cgroup_namespace {
+ atomic_t count;
+ struct ns_common ns;
+ struct user_namespace *user_ns;
+ struct css_set *root_cset;
+};
+
+extern struct cgroup_namespace init_cgroup_ns;
+
+#ifdef CONFIG_CGROUPS
+
+void free_cgroup_ns(struct cgroup_namespace *ns);
+
+struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
+ struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns);
+
+char * cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen);
+
+#else /* !CONFIG_CGROUPS */
+
+static inline void free_cgroup_ns(struct cgroup_namespace *ns) { }
+static inline struct cgroup_namespace *
+copy_cgroup_ns(unsigned long flags, struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns)
+{
+ return old_ns;
+}
+
+#endif /* !CONFIG_CGROUPS */
+
+static inline void get_cgroup_ns(struct cgroup_namespace *ns)
+{
+ if (ns)
+ atomic_inc(&ns->count);
+}
+
+static inline void put_cgroup_ns(struct cgroup_namespace *ns)
+{
+ if (ns && atomic_dec_and_test(&ns->count))
+ free_cgroup_ns(ns);
+}
+
#ifdef CONFIG_CGROUPS
/*
@@ -509,12 +557,6 @@ static inline int cgroup_name(struct cgroup *cgrp, char *buf, size_t buflen)
return kernfs_name(cgrp->kn, buf, buflen);
}
-static inline char * __must_check cgroup_path(struct cgroup *cgrp, char *buf,
- size_t buflen)
-{
- return kernfs_path(cgrp->kn, buf, buflen);
-}
-
static inline void pr_cont_cgroup_name(struct cgroup *cgrp)
{
pr_cont_kernfs_name(cgrp->kn);
diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
index 35fa08f..ac0d65b 100644
--- a/include/linux/nsproxy.h
+++ b/include/linux/nsproxy.h
@@ -8,6 +8,7 @@ struct mnt_namespace;
struct uts_namespace;
struct ipc_namespace;
struct pid_namespace;
+struct cgroup_namespace;
struct fs_struct;
/*
@@ -33,6 +34,7 @@ struct nsproxy {
struct mnt_namespace *mnt_ns;
struct pid_namespace *pid_ns_for_children;
struct net *net_ns;
+ struct cgroup_namespace *cgroup_ns;
};
extern struct nsproxy init_nsproxy;
diff --git a/include/linux/proc_ns.h b/include/linux/proc_ns.h
index 42dfc61..de0e771 100644
--- a/include/linux/proc_ns.h
+++ b/include/linux/proc_ns.h
@@ -9,6 +9,8 @@
struct pid_namespace;
struct nsproxy;
struct path;
+struct task_struct;
+struct inode;
struct proc_ns_operations {
const char *name;
@@ -24,6 +26,7 @@ extern const struct proc_ns_operations ipcns_operations;
extern const struct proc_ns_operations pidns_operations;
extern const struct proc_ns_operations userns_operations;
extern const struct proc_ns_operations mntns_operations;
+extern const struct proc_ns_operations cgroupns_operations;
/*
* We always define these enumerators
@@ -34,6 +37,7 @@ enum {
PROC_UTS_INIT_INO = 0xEFFFFFFEU,
PROC_USER_INIT_INO = 0xEFFFFFFDU,
PROC_PID_INIT_INO = 0xEFFFFFFCU,
+ PROC_CGROUP_INIT_INO = 0xEFFFFFFBU,
};
#ifdef CONFIG_PROC_FS
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 7f2f007..92db64c 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -57,6 +57,9 @@
#include <linux/vmalloc.h> /* TODO: replace with more sophisticated array */
#include <linux/kthread.h>
#include <linux/delay.h>
+#include <linux/proc_ns.h>
+#include <linux/nsproxy.h>
+#include <linux/proc_ns.h>
#include <linux/atomic.h>
@@ -208,6 +211,15 @@ static unsigned long have_fork_callback __read_mostly;
static unsigned long have_exit_callback __read_mostly;
static unsigned long have_free_callback __read_mostly;
+/* Cgroup namespace for init task */
+struct cgroup_namespace init_cgroup_ns = {
+ .count = { .counter = 1, },
+ .user_ns = &init_user_ns,
+ .ns.ops = &cgroupns_operations,
+ .ns.inum = PROC_CGROUP_INIT_INO,
+ .root_cset = &init_css_set,
+};
+
/* Ditto for the can_fork callback. */
static unsigned long have_canfork_callback __read_mostly;
@@ -430,18 +442,18 @@ static inline bool cgroup_is_dead(const struct cgroup *cgrp)
return !(cgrp->self.flags & CSS_ONLINE);
}
-static void cgroup_get(struct cgroup *cgrp)
+static inline void cgroup_get(struct cgroup *cgrp)
{
WARN_ON_ONCE(cgroup_is_dead(cgrp));
css_get(&cgrp->self);
}
-static bool cgroup_tryget(struct cgroup *cgrp)
+static inline bool cgroup_tryget(struct cgroup *cgrp)
{
return css_tryget(&cgrp->self);
}
-static void cgroup_put(struct cgroup *cgrp)
+static inline void cgroup_put(struct cgroup *cgrp)
{
css_put(&cgrp->self);
}
@@ -2189,6 +2201,22 @@ static struct file_system_type cgroup2_fs_type = {
.kill_sb = cgroup_kill_sb,
};
+static char * cgroup_path_ns(struct cgroup *cgrp, char *buf, size_t buflen,
+ struct cgroup_namespace *ns)
+{
+ struct cgroup *root;
+
+ root = cset_cgroup_from_root(ns->root_cset, cgrp->root);
+ return kernfs_path_from_node(root->kn, cgrp->kn, buf, buflen);
+}
+
+char * cgroup_path(struct cgroup *cgrp, char *buf, size_t buflen)
+{
+ return cgroup_path_ns(cgrp, buf, buflen,
+ current->nsproxy->cgroup_ns);
+}
+EXPORT_SYMBOL_GPL(cgroup_path);
+
/**
* task_cgroup_path - cgroup path of a task in the first cgroup hierarchy
* @task: target task
@@ -5289,6 +5317,8 @@ int __init cgroup_init(void)
BUG_ON(cgroup_init_cftypes(NULL, cgroup_dfl_base_files));
BUG_ON(cgroup_init_cftypes(NULL, cgroup_legacy_base_files));
+ get_user_ns(init_cgroup_ns.user_ns);
+
mutex_lock(&cgroup_mutex);
/* Add init_css_set to the hash table */
@@ -5805,6 +5835,116 @@ struct cgroup_subsys_state *css_from_id(int id, struct cgroup_subsys *ss)
return id > 0 ? idr_find(&ss->css_idr, id) : NULL;
}
+/* cgroup namespaces */
+
+static struct cgroup_namespace *alloc_cgroup_ns(void)
+{
+ struct cgroup_namespace *new_ns;
+ int ret;
+
+ new_ns = kzalloc(sizeof(struct cgroup_namespace), GFP_KERNEL);
+ if (!new_ns)
+ return ERR_PTR(-ENOMEM);
+ ret = ns_alloc_inum(&new_ns->ns);
+ if (ret) {
+ kfree(new_ns);
+ return ERR_PTR(ret);
+ }
+ atomic_set(&new_ns->count, 1);
+ new_ns->ns.ops = &cgroupns_operations;
+ return new_ns;
+}
+
+void free_cgroup_ns(struct cgroup_namespace *ns)
+{
+ put_css_set(ns->root_cset);
+ put_user_ns(ns->user_ns);
+ ns_free_inum(&ns->ns);
+ kfree(ns);
+}
+EXPORT_SYMBOL(free_cgroup_ns);
+
+struct cgroup_namespace *copy_cgroup_ns(unsigned long flags,
+ struct user_namespace *user_ns,
+ struct cgroup_namespace *old_ns)
+{
+ struct cgroup_namespace *new_ns = NULL;
+ struct css_set *cset = NULL;
+ int err;
+
+ BUG_ON(!old_ns);
+
+ if (!(flags & CLONE_NEWCGROUP)) {
+ get_cgroup_ns(old_ns);
+ return old_ns;
+ }
+
+ /* Allow only sysadmin to create cgroup namespace. */
+ err = -EPERM;
+ if (!ns_capable(user_ns, CAP_SYS_ADMIN))
+ goto err_out;
+
+ cset = task_css_set(current);
+ get_css_set(cset);
+
+ err = -ENOMEM;
+ new_ns = alloc_cgroup_ns();
+ if (!new_ns)
+ goto err_out;
+
+ new_ns->user_ns = get_user_ns(user_ns);
+ new_ns->root_cset = cset;
+
+ return new_ns;
+
+err_out:
+ if (cset)
+ put_css_set(cset);
+ kfree(new_ns);
+ return ERR_PTR(err);
+}
+
+static int cgroupns_install(struct nsproxy *nsproxy, void *ns)
+{
+ pr_info("setns not supported for cgroup namespace");
+ return -EINVAL;
+}
+
+static struct ns_common *cgroupns_get(struct task_struct *task)
+{
+ struct cgroup_namespace *ns = NULL;
+ struct nsproxy *nsproxy;
+
+ task_lock(task);
+ nsproxy = task->nsproxy;
+ if (nsproxy) {
+ ns = nsproxy->cgroup_ns;
+ get_cgroup_ns(ns);
+ }
+ task_unlock(task);
+
+ return ns ? &ns->ns : NULL;
+}
+
+static void cgroupns_put(struct ns_common *ns)
+{
+ put_cgroup_ns(to_cg_ns(ns));
+}
+
+const struct proc_ns_operations cgroupns_operations = {
+ .name = "cgroup",
+ .type = CLONE_NEWCGROUP,
+ .get = cgroupns_get,
+ .put = cgroupns_put,
+ .install = cgroupns_install,
+};
+
+static __init int cgroup_namespaces_init(void)
+{
+ return 0;
+}
+subsys_initcall(cgroup_namespaces_init);
+
#ifdef CONFIG_CGROUP_DEBUG
static struct cgroup_subsys_state *
debug_css_alloc(struct cgroup_subsys_state *parent_css)
diff --git a/kernel/fork.c b/kernel/fork.c
index ba7d1c0..7982fee 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1880,7 +1880,7 @@ static int check_unshare_flags(unsigned long unshare_flags)
if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET|
- CLONE_NEWUSER|CLONE_NEWPID))
+ CLONE_NEWUSER|CLONE_NEWPID|CLONE_NEWCGROUP))
return -EINVAL;
/*
* Not implemented, but pretend it works if there is nothing
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 49746c8..64fe865 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -25,6 +25,7 @@
#include <linux/proc_ns.h>
#include <linux/file.h>
#include <linux/syscalls.h>
+#include <linux/cgroup.h>
static struct kmem_cache *nsproxy_cachep;
@@ -39,6 +40,9 @@ struct nsproxy init_nsproxy = {
#ifdef CONFIG_NET
.net_ns = &init_net,
#endif
+#ifdef CONFIG_CGROUPS
+ .cgroup_ns = &init_cgroup_ns,
+#endif
};
static inline struct nsproxy *create_nsproxy(void)
@@ -92,6 +96,13 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
goto out_pid;
}
+ new_nsp->cgroup_ns = copy_cgroup_ns(flags, user_ns,
+ tsk->nsproxy->cgroup_ns);
+ if (IS_ERR(new_nsp->cgroup_ns)) {
+ err = PTR_ERR(new_nsp->cgroup_ns);
+ goto out_cgroup;
+ }
+
new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
if (IS_ERR(new_nsp->net_ns)) {
err = PTR_ERR(new_nsp->net_ns);
@@ -101,6 +112,9 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
return new_nsp;
out_net:
+ if (new_nsp->cgroup_ns)
+ put_cgroup_ns(new_nsp->cgroup_ns);
+out_cgroup:
if (new_nsp->pid_ns_for_children)
put_pid_ns(new_nsp->pid_ns_for_children);
out_pid:
@@ -128,7 +142,8 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
struct nsproxy *new_ns;
if (likely(!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWPID | CLONE_NEWNET)))) {
+ CLONE_NEWPID | CLONE_NEWNET |
+ CLONE_NEWCGROUP)))) {
get_nsproxy(old_ns);
return 0;
}
@@ -165,6 +180,8 @@ void free_nsproxy(struct nsproxy *ns)
put_ipc_ns(ns->ipc_ns);
if (ns->pid_ns_for_children)
put_pid_ns(ns->pid_ns_for_children);
+ if (ns->cgroup_ns)
+ put_cgroup_ns(ns->cgroup_ns);
put_net(ns->net_ns);
kmem_cache_free(nsproxy_cachep, ns);
}
@@ -180,7 +197,7 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
int err = 0;
if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWNET | CLONE_NEWPID)))
+ CLONE_NEWNET | CLONE_NEWPID | CLONE_NEWCGROUP)))
return 0;
user_ns = new_cred ? new_cred->user_ns : current_user_ns();
--
1.7.9.5
^ permalink raw reply related [flat|nested] 19+ messages in thread
end of thread, other threads:[~2016-01-29 8:56 UTC | newest]
Thread overview: 19+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-01-04 19:54 CGroup Namespaces (v9) serge.hallyn
2016-01-04 19:54 ` [PATCH 1/8] kernfs: Add API to generate relative kernfs path serge.hallyn
2016-01-04 19:54 ` [PATCH 2/8] sched: new clone flag CLONE_NEWCGROUP for cgroup namespace serge.hallyn
2016-01-04 19:54 ` [PATCH 3/8] cgroup: introduce cgroup namespaces serge.hallyn
2016-01-04 20:20 ` Serge E. Hallyn
2016-01-04 21:47 ` Johannes Weiner
2016-01-05 2:07 ` [PATCH 3/8 v2] " Serge E. Hallyn
2016-01-06 2:17 ` [PATCH 3/8 v3] " Serge E. Hallyn
2016-01-04 19:54 ` [PATCH 4/8] cgroup: cgroup namespace setns support serge.hallyn
2016-01-04 19:54 ` [PATCH 5/8] kernfs: define kernfs_node_dentry serge.hallyn
2016-01-04 19:54 ` [PATCH 6/8] cgroup: mount cgroupns-root when inside non-init cgroupns serge.hallyn
2016-01-04 19:54 ` [PATCH 7/8] cgroup: Add documentation for cgroup namespaces serge.hallyn
2016-01-04 19:54 ` [PATCH 8/8] Add FS_USERNS_FLAG to cgroup fs serge.hallyn
2016-01-05 0:53 ` CGroup Namespaces (v9) Serge E. Hallyn
2016-01-05 19:36 ` Serge E. Hallyn
-- strict thread matches above, loose matches on Subject: below --
2016-01-29 8:54 CGroup Namespaces (v10) serge.hallyn
2016-01-29 8:54 ` [PATCH 3/8] cgroup: introduce cgroup namespaces serge.hallyn
2015-12-23 4:23 CGroup Namespaces (v8) serge.hallyn
2015-12-23 4:23 ` [PATCH 3/8] cgroup: introduce cgroup namespaces serge.hallyn
2015-12-23 16:15 ` Tejun Heo
2015-12-09 19:28 CGroup Namespaces (v7) serge.hallyn
2015-12-09 19:28 ` [PATCH 3/8] cgroup: introduce cgroup namespaces serge.hallyn
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