[PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[Serge E. Hallyn]

To do so we need to pass in the task_struct who'll get the utsname,
so we can get its user_ns.

Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
---
 include/linux/utsname.h |   10 ++++++----
 kernel/nsproxy.c        |    7 +------
 kernel/utsname.c        |   12 +++++++-----
 3 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 85171be..165b17b 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -52,8 +52,9 @@ static inline void get_uts_ns(struct uts_namespace *ns)
 	kref_get(&ns->kref);
 }
 
-extern struct uts_namespace *copy_utsname(unsigned long flags,
-					struct uts_namespace *ns);
+extern struct uts_namespace *copy_utsname(struct task_struct *tsk,
+					  unsigned long flags,
+					  struct uts_namespace *ns);
 extern void free_uts_ns(struct kref *kref);
 
 static inline void put_uts_ns(struct uts_namespace *ns)
@@ -69,8 +70,9 @@ static inline void put_uts_ns(struct uts_namespace *ns)
 {
 }
 
-static inline struct uts_namespace *copy_utsname(unsigned long flags,
-					struct uts_namespace *ns)
+static inline struct uts_namespace *copy_utsname(struct task_struct *tsk,
+						 unsigned long flags,
+						 struct uts_namespace *ns)
 {
 	if (flags & CLONE_NEWUTS)
 		return ERR_PTR(-EINVAL);
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index b6dbff2..ffa6b67 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -69,16 +69,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 		goto out_ns;
 	}
 
-	new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
+	new_nsp->uts_ns = copy_utsname(tsk, flags, tsk->nsproxy->uts_ns);
 	if (IS_ERR(new_nsp->uts_ns)) {
 		err = PTR_ERR(new_nsp->uts_ns);
 		goto out_uts;
 	}
-	if (new_nsp->uts_ns != tsk->nsproxy->uts_ns) {
-		put_user_ns(new_nsp->uts_ns->user_ns);
-		new_nsp->uts_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;
-		get_user_ns(new_nsp->uts_ns->user_ns);
-	}
 
 	new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
 	if (IS_ERR(new_nsp->ipc_ns)) {
diff --git a/kernel/utsname.c b/kernel/utsname.c
index a7b3a8d..9462580 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -31,7 +31,8 @@ static struct uts_namespace *create_uts_ns(void)
  * @old_ns: namespace to clone
  * Return NULL on error (failure to kmalloc), new ns otherwise
  */
-static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
+static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
+					  struct uts_namespace *old_ns)
 {
 	struct uts_namespace *ns;
 
@@ -41,8 +42,7 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
 
 	down_read(&uts_sem);
 	memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
-	ns->user_ns = old_ns->user_ns;
-	get_user_ns(ns->user_ns);
+	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
 	up_read(&uts_sem);
 	return ns;
 }
@@ -53,7 +53,9 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
  * utsname of this process won't be seen by parent, and vice
  * versa.
  */
-struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *old_ns)
+struct uts_namespace *copy_utsname(struct task_struct *tsk,
+				   unsigned long flags,
+				   struct uts_namespace *old_ns)
 {
 	struct uts_namespace *new_ns;
 
@@ -63,7 +65,7 @@ struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *ol
 	if (!(flags & CLONE_NEWUTS))
 		return old_ns;
 
-	new_ns = clone_uts_ns(old_ns);
+	new_ns = clone_uts_ns(tsk, old_ns);
 
 	put_uts_ns(old_ns);
 	return new_ns;
-- 
1.7.0.4

[PATCH 2/4] userns: let copy_ipcs handle setting ipc_ns->user_ns

[Serge E. Hallyn]

To do that, we have to pass in the task_struct of the task which
will own the ipc_ns, so we can assign its user_ns.

Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
---
 include/linux/ipc_namespace.h |    8 +++++---
 ipc/namespace.c               |   12 +++++++-----
 kernel/nsproxy.c              |    7 +------
 3 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index 46d2eb4..9974429 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -92,7 +92,8 @@ static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
 #endif
 
 #if defined(CONFIG_IPC_NS)
-extern struct ipc_namespace *copy_ipcs(unsigned long flags,
+extern struct ipc_namespace *copy_ipcs(struct task_struct *tsk,
+				       unsigned long flags,
 				       struct ipc_namespace *ns);
 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
 {
@@ -103,8 +104,9 @@ static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
 
 extern void put_ipc_ns(struct ipc_namespace *ns);
 #else
-static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
-		struct ipc_namespace *ns)
+static inline struct ipc_namespace *copy_ipcs(struct task_struct *tsk,
+					      unsigned long flags,
+					      struct ipc_namespace *ns)
 {
 	if (flags & CLONE_NEWIPC)
 		return ERR_PTR(-EINVAL);
diff --git a/ipc/namespace.c b/ipc/namespace.c
index aa18899..ee84882 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -15,7 +15,8 @@
 
 #include "util.h"
 
-static struct ipc_namespace *create_ipc_ns(struct ipc_namespace *old_ns)
+static struct ipc_namespace *create_ipc_ns(struct task_struct *tsk,
+					   struct ipc_namespace *old_ns)
 {
 	struct ipc_namespace *ns;
 	int err;
@@ -44,17 +45,18 @@ static struct ipc_namespace *create_ipc_ns(struct ipc_namespace *old_ns)
 	ipcns_notify(IPCNS_CREATED);
 	register_ipcns_notifier(ns);
 
-	ns->user_ns = old_ns->user_ns;
-	get_user_ns(ns->user_ns);
+	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
 
 	return ns;
 }
 
-struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
+struct ipc_namespace *copy_ipcs(struct task_struct *tsk,
+				unsigned long flags,
+				struct ipc_namespace *ns)
 {
 	if (!(flags & CLONE_NEWIPC))
 		return get_ipc_ns(ns);
-	return create_ipc_ns(ns);
+	return create_ipc_ns(tsk, ns);
 }
 
 /*
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index ffa6b67..b905ecc 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -75,16 +75,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 		goto out_uts;
 	}
 
-	new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
+	new_nsp->ipc_ns = copy_ipcs(tsk, flags, tsk->nsproxy->ipc_ns);
 	if (IS_ERR(new_nsp->ipc_ns)) {
 		err = PTR_ERR(new_nsp->ipc_ns);
 		goto out_ipc;
 	}
-	if (new_nsp->ipc_ns != tsk->nsproxy->ipc_ns) {
-		put_user_ns(new_nsp->ipc_ns->user_ns);
-		new_nsp->ipc_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;
-		get_user_ns(new_nsp->ipc_ns->user_ns);
-	}
 
 	new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));
 	if (IS_ERR(new_nsp->pid_ns)) {
-- 
1.7.0.4

Re: [PATCH 2/4] userns: let copy_ipcs handle setting ipc_ns->user_ns

[Daniel Lezcano]

On 02/21/2011 05:02 AM, Serge E. Hallyn wrote:
> To do that, we have to pass in the task_struct of the task which
> will own the ipc_ns, so we can assign its user_ns.
>
> Signed-off-by: Serge E. Hallyn<serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
> ---
>   include/linux/ipc_namespace.h |    8 +++++---
>   ipc/namespace.c               |   12 +++++++-----
>   kernel/nsproxy.c              |    7 +------
>   3 files changed, 13 insertions(+), 14 deletions(-)
>
> diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
> index 46d2eb4..9974429 100644
> --- a/include/linux/ipc_namespace.h
> +++ b/include/linux/ipc_namespace.h
> @@ -92,7 +92,8 @@ static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
>   #endif
>
>   #if defined(CONFIG_IPC_NS)
> -extern struct ipc_namespace *copy_ipcs(unsigned long flags,
> +extern struct ipc_namespace *copy_ipcs(struct task_struct *tsk,
> +				       unsigned long flags,
>   				       struct ipc_namespace *ns);

Same comment than patch 1/4

[PATCH 2/4] userns: let copy_ipcs handle setting ipc_ns->user_ns

[Serge E. Hallyn]

To do that, we have to pass in the task_struct of the task which
will own the ipc_ns, so we can assign its user_ns.

Changelog:
	Feb 23: As per Oleg comment, just pass in tsk.  To get the
	        ipc_ns from the nsproxy we need to include nsproxy.h

Signed-off-by: Serge E. Hallyn <serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
---
 include/linux/ipc_namespace.h |    7 ++++---
 ipc/namespace.c               |   13 ++++++++-----
 kernel/nsproxy.c              |    7 +------
 3 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index 46d2eb4..c079d09 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -5,6 +5,7 @@
 #include <linux/idr.h>
 #include <linux/rwsem.h>
 #include <linux/notifier.h>
+#include <linux/nsproxy.h>
 
 /*
  * ipc namespace events
@@ -93,7 +94,7 @@ static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
 
 #if defined(CONFIG_IPC_NS)
 extern struct ipc_namespace *copy_ipcs(unsigned long flags,
-				       struct ipc_namespace *ns);
+				       struct task_struct *tsk);
 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
 {
 	if (ns)
@@ -104,12 +105,12 @@ static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
 extern void put_ipc_ns(struct ipc_namespace *ns);
 #else
 static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
-		struct ipc_namespace *ns)
+					      struct task_struct *tsk)
 {
 	if (flags & CLONE_NEWIPC)
 		return ERR_PTR(-EINVAL);
 
-	return ns;
+	return tsk->nsproxy->ipc_ns;
 }
 
 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
diff --git a/ipc/namespace.c b/ipc/namespace.c
index aa18899..3c3e522 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -15,7 +15,8 @@
 
 #include "util.h"
 
-static struct ipc_namespace *create_ipc_ns(struct ipc_namespace *old_ns)
+static struct ipc_namespace *create_ipc_ns(struct task_struct *tsk,
+					   struct ipc_namespace *old_ns)
 {
 	struct ipc_namespace *ns;
 	int err;
@@ -44,17 +45,19 @@ static struct ipc_namespace *create_ipc_ns(struct ipc_namespace *old_ns)
 	ipcns_notify(IPCNS_CREATED);
 	register_ipcns_notifier(ns);
 
-	ns->user_ns = old_ns->user_ns;
-	get_user_ns(ns->user_ns);
+	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
 
 	return ns;
 }
 
-struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
+struct ipc_namespace *copy_ipcs(unsigned long flags,
+				struct task_struct *tsk)
 {
+	struct ipc_namespace *ns = tsk->nsproxy->ipc_ns;
+
 	if (!(flags & CLONE_NEWIPC))
 		return get_ipc_ns(ns);
-	return create_ipc_ns(ns);
+	return create_ipc_ns(tsk, ns);
 }
 
 /*
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index ac8a56e..a05d191 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -75,16 +75,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 		goto out_uts;
 	}
 
-	new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
+	new_nsp->ipc_ns = copy_ipcs(flags, tsk);
 	if (IS_ERR(new_nsp->ipc_ns)) {
 		err = PTR_ERR(new_nsp->ipc_ns);
 		goto out_ipc;
 	}
-	if (new_nsp->ipc_ns != tsk->nsproxy->ipc_ns) {
-		put_user_ns(new_nsp->ipc_ns->user_ns);
-		new_nsp->ipc_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;
-		get_user_ns(new_nsp->ipc_ns->user_ns);
-	}
 
 	new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));
 	if (IS_ERR(new_nsp->pid_ns)) {
-- 
1.7.0.4

Re: [PATCH 2/4] userns: let copy_ipcs handle setting ipc_ns->user_ns

[Daniel Lezcano]

On 02/21/2011 05:02 AM, Serge E. Hallyn wrote:
> To do that, we have to pass in the task_struct of the task which
> will own the ipc_ns, so we can assign its user_ns.
>
> Signed-off-by: Serge E. Hallyn<serge.hallyn@canonical.com>
> ---
>   include/linux/ipc_namespace.h |    8 +++++---
>   ipc/namespace.c               |   12 +++++++-----
>   kernel/nsproxy.c              |    7 +------
>   3 files changed, 13 insertions(+), 14 deletions(-)
>
> diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
> index 46d2eb4..9974429 100644
> --- a/include/linux/ipc_namespace.h
> +++ b/include/linux/ipc_namespace.h
> @@ -92,7 +92,8 @@ static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
>   #endif
>
>   #if defined(CONFIG_IPC_NS)
> -extern struct ipc_namespace *copy_ipcs(unsigned long flags,
> +extern struct ipc_namespace *copy_ipcs(struct task_struct *tsk,
> +				       unsigned long flags,
>   				       struct ipc_namespace *ns);

Same comment than patch 1/4

[PATCH 2/4] userns: let copy_ipcs handle setting ipc_ns->user_ns

[Serge E. Hallyn]

To do that, we have to pass in the task_struct of the task which
will own the ipc_ns, so we can assign its user_ns.

Changelog:
	Feb 23: As per Oleg comment, just pass in tsk.  To get the
	        ipc_ns from the nsproxy we need to include nsproxy.h

Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
---
 include/linux/ipc_namespace.h |    7 ++++---
 ipc/namespace.c               |   13 ++++++++-----
 kernel/nsproxy.c              |    7 +------
 3 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index 46d2eb4..c079d09 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -5,6 +5,7 @@
 #include <linux/idr.h>
 #include <linux/rwsem.h>
 #include <linux/notifier.h>
+#include <linux/nsproxy.h>
 
 /*
  * ipc namespace events
@@ -93,7 +94,7 @@ static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
 
 #if defined(CONFIG_IPC_NS)
 extern struct ipc_namespace *copy_ipcs(unsigned long flags,
-				       struct ipc_namespace *ns);
+				       struct task_struct *tsk);
 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
 {
 	if (ns)
@@ -104,12 +105,12 @@ static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
 extern void put_ipc_ns(struct ipc_namespace *ns);
 #else
 static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
-		struct ipc_namespace *ns)
+					      struct task_struct *tsk)
 {
 	if (flags & CLONE_NEWIPC)
 		return ERR_PTR(-EINVAL);
 
-	return ns;
+	return tsk->nsproxy->ipc_ns;
 }
 
 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
diff --git a/ipc/namespace.c b/ipc/namespace.c
index aa18899..3c3e522 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -15,7 +15,8 @@
 
 #include "util.h"
 
-static struct ipc_namespace *create_ipc_ns(struct ipc_namespace *old_ns)
+static struct ipc_namespace *create_ipc_ns(struct task_struct *tsk,
+					   struct ipc_namespace *old_ns)
 {
 	struct ipc_namespace *ns;
 	int err;
@@ -44,17 +45,19 @@ static struct ipc_namespace *create_ipc_ns(struct ipc_namespace *old_ns)
 	ipcns_notify(IPCNS_CREATED);
 	register_ipcns_notifier(ns);
 
-	ns->user_ns = old_ns->user_ns;
-	get_user_ns(ns->user_ns);
+	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
 
 	return ns;
 }
 
-struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
+struct ipc_namespace *copy_ipcs(unsigned long flags,
+				struct task_struct *tsk)
 {
+	struct ipc_namespace *ns = tsk->nsproxy->ipc_ns;
+
 	if (!(flags & CLONE_NEWIPC))
 		return get_ipc_ns(ns);
-	return create_ipc_ns(ns);
+	return create_ipc_ns(tsk, ns);
 }
 
 /*
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index ac8a56e..a05d191 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -75,16 +75,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 		goto out_uts;
 	}
 
-	new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
+	new_nsp->ipc_ns = copy_ipcs(flags, tsk);
 	if (IS_ERR(new_nsp->ipc_ns)) {
 		err = PTR_ERR(new_nsp->ipc_ns);
 		goto out_ipc;
 	}
-	if (new_nsp->ipc_ns != tsk->nsproxy->ipc_ns) {
-		put_user_ns(new_nsp->ipc_ns->user_ns);
-		new_nsp->ipc_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;
-		get_user_ns(new_nsp->ipc_ns->user_ns);
-	}
 
 	new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));
 	if (IS_ERR(new_nsp->pid_ns)) {
-- 
1.7.0.4

Re: [PATCH 2/4] userns: let copy_ipcs handle setting ipc_ns->user_ns

[Daniel Lezcano]

On 02/24/2011 01:22 AM, Serge E. Hallyn wrote:
> To do that, we have to pass in the task_struct of the task which
> will own the ipc_ns, so we can assign its user_ns.
>
> Changelog:
> 	Feb 23: As per Oleg comment, just pass in tsk.  To get the
> 	        ipc_ns from the nsproxy we need to include nsproxy.h
>
> Signed-off-by: Serge E. Hallyn<serge.hallyn@canonical.com>
> ---

Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>

Re: [PATCH 2/4] userns: let copy_ipcs handle setting ipc_ns->user_ns

[Daniel Lezcano]

On 02/24/2011 01:22 AM, Serge E. Hallyn wrote:
> To do that, we have to pass in the task_struct of the task which
> will own the ipc_ns, so we can assign its user_ns.
>
> Changelog:
> 	Feb 23: As per Oleg comment, just pass in tsk.  To get the
> 	        ipc_ns from the nsproxy we need to include nsproxy.h
>
> Signed-off-by: Serge E. Hallyn<serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
> ---

Acked-by: Daniel Lezcano <daniel.lezcano-GANU6spQydw@public.gmane.org>

[PATCH 3/4] Add the required user_ns parameter to security_capable

[Serge E. Hallyn]

Fixes a compile failure.

Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
---
 drivers/pci/pci-sysfs.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index ea25e5b..90a6b04 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -369,7 +369,7 @@ pci_read_config(struct file *filp, struct kobject *kobj,
 	u8 *data = (u8*) buf;
 
 	/* Several chips lock up trying to read undefined config space */
-	if (security_capable(filp->f_cred, CAP_SYS_ADMIN) == 0) {
+	if (security_capable(&init_user_ns, filp->f_cred, CAP_SYS_ADMIN) == 0) {
 		size = dev->cfg_size;
 	} else if (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS) {
 		size = 128;
-- 
1.7.0.4

[PATCH 4/4] userns: uts and ipc: fix checkpatch warning

[Serge E. Hallyn]

As pointed out by Andrew Morton (and checkpatch), init/version.c
(and ipc/msgutil.c) should not have an extern declaration for
init_user_ns.  Instead, move those to ipc_namespace.h and utsname.h.

Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
---
 include/linux/ipc_namespace.h |    3 ++-
 include/linux/utsname.h       |    1 +
 init/version.c                |    1 -
 ipc/msgutil.c                 |    2 --
 4 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index 9974429..ebd4a93 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -15,6 +15,8 @@
 
 #define IPCNS_CALLBACK_PRI 0
 
+struct user_namespace;
+extern struct user_namespace init_user_ns;
 
 struct ipc_ids {
 	int in_use;
@@ -24,7 +26,6 @@ struct ipc_ids {
 	struct idr ipcs_idr;
 };
 
-struct user_namespace;
 struct ipc_namespace {
 	atomic_t	count;
 	struct ipc_ids	ids[3];
diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 165b17b..69957ca 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -38,6 +38,7 @@ struct new_utsname {
 #include <linux/err.h>
 
 struct user_namespace;
+extern struct user_namespace init_user_ns;
 
 struct uts_namespace {
 	struct kref kref;
diff --git a/init/version.c b/init/version.c
index 97bb86f..86fe0cc 100644
--- a/init/version.c
+++ b/init/version.c
@@ -21,7 +21,6 @@ extern int version_string(LINUX_VERSION_CODE);
 int version_string(LINUX_VERSION_CODE);
 #endif
 
-extern struct user_namespace init_user_ns;
 struct uts_namespace init_uts_ns = {
 	.kref = {
 		.refcount	= ATOMIC_INIT(2),
diff --git a/ipc/msgutil.c b/ipc/msgutil.c
index d91ff4b..8b5ce5d 100644
--- a/ipc/msgutil.c
+++ b/ipc/msgutil.c
@@ -20,8 +20,6 @@
 
 DEFINE_SPINLOCK(mq_lock);
 
-extern struct user_namespace init_user_ns;
-
 /*
  * The next 2 defines are here bc this is the only file
  * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE
-- 
1.7.0.4

Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[Daniel Lezcano]

On 02/21/2011 05:01 AM, Serge E. Hallyn wrote:
> To do so we need to pass in the task_struct who'll get the utsname,
> so we can get its user_ns.
>
> Signed-off-by: Serge E. Hallyn<serge.hallyn@canonical.com>
> ---


>   include/linux/utsname.h |   10 ++++++----
>   kernel/nsproxy.c        |    7 +------
>   kernel/utsname.c        |   12 +++++++-----
>   3 files changed, 14 insertions(+), 15 deletions(-)
>
> diff --git a/include/linux/utsname.h b/include/linux/utsname.h
> index 85171be..165b17b 100644
> --- a/include/linux/utsname.h
> +++ b/include/linux/utsname.h
> @@ -52,8 +52,9 @@ static inline void get_uts_ns(struct uts_namespace *ns)
>   	kref_get(&ns->kref);
>   }
>
> -extern struct uts_namespace *copy_utsname(unsigned long flags,
> -					struct uts_namespace *ns);
> +extern struct uts_namespace *copy_utsname(struct task_struct *tsk,
> +					  unsigned long flags,
> +					  struct uts_namespace *ns);

Why don't we pass 'user_ns' instead of 'tsk' ? that will look 
semantically clearer for the caller no ?
(example below).

>   extern void free_uts_ns(struct kref *kref);
>
>   static inline void put_uts_ns(struct uts_namespace *ns)
> @@ -69,8 +70,9 @@ static inline void put_uts_ns(struct uts_namespace *ns)
>   {
>   }
>
> -static inline struct uts_namespace *copy_utsname(unsigned long flags,
> -					struct uts_namespace *ns)
> +static inline struct uts_namespace *copy_utsname(struct task_struct *tsk,
> +						 unsigned long flags,
> +						 struct uts_namespace *ns)
>   {
>   	if (flags&  CLONE_NEWUTS)
>   		return ERR_PTR(-EINVAL);
> diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
> index b6dbff2..ffa6b67 100644
> --- a/kernel/nsproxy.c
> +++ b/kernel/nsproxy.c
> @@ -69,16 +69,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
>   		goto out_ns;
>   	}
>
> -	new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
> +	new_nsp->uts_ns = copy_utsname(tsk, flags, tsk->nsproxy->uts_ns);
>   	if (IS_ERR(new_nsp->uts_ns)) {
>   		err = PTR_ERR(new_nsp->uts_ns);
>   		goto out_uts;
>   	}

...

new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns, task_cred_xxx(tsk, user)->user_ns);

...

> -	if (new_nsp->uts_ns != tsk->nsproxy->uts_ns) {
> -		put_user_ns(new_nsp->uts_ns->user_ns);
> -		new_nsp->uts_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;
> -		get_user_ns(new_nsp->uts_ns->user_ns);
> -	}
>
>   	new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
>   	if (IS_ERR(new_nsp->ipc_ns)) {
> diff --git a/kernel/utsname.c b/kernel/utsname.c
> index a7b3a8d..9462580 100644
> --- a/kernel/utsname.c
> +++ b/kernel/utsname.c
> @@ -31,7 +31,8 @@ static struct uts_namespace *create_uts_ns(void)
>    * @old_ns: namespace to clone
>    * Return NULL on error (failure to kmalloc), new ns otherwise
>    */
> -static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
> +static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
> +					  struct uts_namespace *old_ns)
>   {
>   	struct uts_namespace *ns;
>
> @@ -41,8 +42,7 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
>
>   	down_read(&uts_sem);
>   	memcpy(&ns->name,&old_ns->name, sizeof(ns->name));
> -	ns->user_ns = old_ns->user_ns;
> -	get_user_ns(ns->user_ns);
> +	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
>   	up_read(&uts_sem);
>   	return ns;
>   }
> @@ -53,7 +53,9 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
>    * utsname of this process won't be seen by parent, and vice
>    * versa.
>    */
> -struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *old_ns)
> +struct uts_namespace *copy_utsname(struct task_struct *tsk,
> +				   unsigned long flags,
> +				   struct uts_namespace *old_ns)
>   {
>   	struct uts_namespace *new_ns;
>
> @@ -63,7 +65,7 @@ struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *ol
>   	if (!(flags&  CLONE_NEWUTS))
>   		return old_ns;
>
> -	new_ns = clone_uts_ns(old_ns);
> +	new_ns = clone_uts_ns(tsk, old_ns);
>
>   	put_uts_ns(old_ns);
>   	return new_ns;

Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[Oleg Nesterov]

On 02/21, Daniel Lezcano wrote:
>
> On 02/21/2011 05:01 AM, Serge E. Hallyn wrote:
>> To do so we need to pass in the task_struct who'll get the utsname,
>> so we can get its user_ns.
>>
>> -extern struct uts_namespace *copy_utsname(unsigned long flags,
>> -					struct uts_namespace *ns);
>> +extern struct uts_namespace *copy_utsname(struct task_struct *tsk,
>> +					  unsigned long flags,
>> +					  struct uts_namespace *ns);
>
> Why don't we pass 'user_ns' instead of 'tsk' ? that will look
> semantically clearer for the caller no ?
> (example below).
> ...
>
> new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns, task_cred_xxx(tsk, user)->user_ns);

To me tsk looks more readable, I mean

	new_nsp->uts_ns = copy_utsname(flags, tsk);

copy_utsname() can find both uts_ns and user_ns looking at task_strcut.

But this is cosmetic and up to you and Serge.


But. I think it makes sense to pass "tsk" argument to copy_pid_ns() as well.
This way we can remove some CLONE_PIDNS code in copy_process(), and this
looks like a nice cleanaup (even if minor) to me.

Oleg.

Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[Serge E. Hallyn]

Quoting Oleg Nesterov (oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org):
> On 02/21, Daniel Lezcano wrote:
> >
> > On 02/21/2011 05:01 AM, Serge E. Hallyn wrote:
> >> To do so we need to pass in the task_struct who'll get the utsname,
> >> so we can get its user_ns.
> >>
> >> -extern struct uts_namespace *copy_utsname(unsigned long flags,
> >> -					struct uts_namespace *ns);
> >> +extern struct uts_namespace *copy_utsname(struct task_struct *tsk,
> >> +					  unsigned long flags,
> >> +					  struct uts_namespace *ns);
> >
> > Why don't we pass 'user_ns' instead of 'tsk' ? that will look
> > semantically clearer for the caller no ?
> > (example below).
> > ...
> >
> > new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns, task_cred_xxx(tsk, user)->user_ns);
> 
> To me tsk looks more readable, I mean
> 
> 	new_nsp->uts_ns = copy_utsname(flags, tsk);
> 
> copy_utsname() can find both uts_ns and user_ns looking at task_strcut.

Uh, yeah.  I should remove the 'ns' argument there shouldn't I.

Daniel, does that sway your opinion then?

thanks,
-serge

Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[Serge E. Hallyn]

Quoting Oleg Nesterov (oleg@redhat.com):
> On 02/21, Daniel Lezcano wrote:
> >
> > On 02/21/2011 05:01 AM, Serge E. Hallyn wrote:
> >> To do so we need to pass in the task_struct who'll get the utsname,
> >> so we can get its user_ns.
> >>
> >> -extern struct uts_namespace *copy_utsname(unsigned long flags,
> >> -					struct uts_namespace *ns);
> >> +extern struct uts_namespace *copy_utsname(struct task_struct *tsk,
> >> +					  unsigned long flags,
> >> +					  struct uts_namespace *ns);
> >
> > Why don't we pass 'user_ns' instead of 'tsk' ? that will look
> > semantically clearer for the caller no ?
> > (example below).
> > ...
> >
> > new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns, task_cred_xxx(tsk, user)->user_ns);
> 
> To me tsk looks more readable, I mean
> 
> 	new_nsp->uts_ns = copy_utsname(flags, tsk);
> 
> copy_utsname() can find both uts_ns and user_ns looking at task_strcut.

Uh, yeah.  I should remove the 'ns' argument there shouldn't I.

Daniel, does that sway your opinion then?

thanks,
-serge

Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[Daniel Lezcano]

On 02/21/2011 02:58 PM, Serge E. Hallyn wrote:
> Quoting Oleg Nesterov (oleg@redhat.com):
>> On 02/21, Daniel Lezcano wrote:
>>> On 02/21/2011 05:01 AM, Serge E. Hallyn wrote:
>>>> To do so we need to pass in the task_struct who'll get the utsname,
>>>> so we can get its user_ns.
>>>>
>>>> -extern struct uts_namespace *copy_utsname(unsigned long flags,
>>>> -					struct uts_namespace *ns);
>>>> +extern struct uts_namespace *copy_utsname(struct task_struct *tsk,
>>>> +					  unsigned long flags,
>>>> +					  struct uts_namespace *ns);
>>> Why don't we pass 'user_ns' instead of 'tsk' ? that will look
>>> semantically clearer for the caller no ?
>>> (example below).
>>> ...
>>>
>>> new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns, task_cred_xxx(tsk, user)->user_ns);
>> To me tsk looks more readable, I mean
>>
>> 	new_nsp->uts_ns = copy_utsname(flags, tsk);
>>
>> copy_utsname() can find both uts_ns and user_ns looking at task_strcut.
> Uh, yeah.  I should remove the 'ns' argument there shouldn't I.
>
> Daniel, does that sway your opinion then?

Well, I prefer to pass the needed parameters to a function. AFAICS, 
'tsk' is not really needed but 'user_ns'.
But it is a detail, so if passing the tsk parameter in the other copy_* 
functions helps to cleanup, that will be consistent.
So I am fine with that.

Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[Daniel Lezcano]

On 02/21/2011 02:58 PM, Serge E. Hallyn wrote:
> Quoting Oleg Nesterov (oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org):
>> On 02/21, Daniel Lezcano wrote:
>>> On 02/21/2011 05:01 AM, Serge E. Hallyn wrote:
>>>> To do so we need to pass in the task_struct who'll get the utsname,
>>>> so we can get its user_ns.
>>>>
>>>> -extern struct uts_namespace *copy_utsname(unsigned long flags,
>>>> -					struct uts_namespace *ns);
>>>> +extern struct uts_namespace *copy_utsname(struct task_struct *tsk,
>>>> +					  unsigned long flags,
>>>> +					  struct uts_namespace *ns);
>>> Why don't we pass 'user_ns' instead of 'tsk' ? that will look
>>> semantically clearer for the caller no ?
>>> (example below).
>>> ...
>>>
>>> new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns, task_cred_xxx(tsk, user)->user_ns);
>> To me tsk looks more readable, I mean
>>
>> 	new_nsp->uts_ns = copy_utsname(flags, tsk);
>>
>> copy_utsname() can find both uts_ns and user_ns looking at task_strcut.
> Uh, yeah.  I should remove the 'ns' argument there shouldn't I.
>
> Daniel, does that sway your opinion then?

Well, I prefer to pass the needed parameters to a function. AFAICS, 
'tsk' is not really needed but 'user_ns'.
But it is a detail, so if passing the tsk parameter in the other copy_* 
functions helps to cleanup, that will be consistent.
So I am fine with that.

Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[Oleg Nesterov]

On 02/21, Daniel Lezcano wrote:
>
> On 02/21/2011 05:01 AM, Serge E. Hallyn wrote:
>> To do so we need to pass in the task_struct who'll get the utsname,
>> so we can get its user_ns.
>>
>> -extern struct uts_namespace *copy_utsname(unsigned long flags,
>> -					struct uts_namespace *ns);
>> +extern struct uts_namespace *copy_utsname(struct task_struct *tsk,
>> +					  unsigned long flags,
>> +					  struct uts_namespace *ns);
>
> Why don't we pass 'user_ns' instead of 'tsk' ? that will look
> semantically clearer for the caller no ?
> (example below).
> ...
>
> new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns, task_cred_xxx(tsk, user)->user_ns);

To me tsk looks more readable, I mean

	new_nsp->uts_ns = copy_utsname(flags, tsk);

copy_utsname() can find both uts_ns and user_ns looking at task_strcut.

But this is cosmetic and up to you and Serge.


But. I think it makes sense to pass "tsk" argument to copy_pid_ns() as well.
This way we can remove some CLONE_PIDNS code in copy_process(), and this
looks like a nice cleanaup (even if minor) to me.

Oleg.

[PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[Serge E. Hallyn]

To do so we need to pass in the task_struct who'll get the utsname,
so we can get its user_ns.

Changelog:
	Feb 23: As per Oleg's coment, just pass in tsk.

Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
---
 include/linux/utsname.h |    6 +++---
 kernel/nsproxy.c        |    7 +------
 kernel/utsname.c        |   12 +++++++-----
 3 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 85171be..21b4566 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -53,7 +53,7 @@ static inline void get_uts_ns(struct uts_namespace *ns)
 }
 
 extern struct uts_namespace *copy_utsname(unsigned long flags,
-					struct uts_namespace *ns);
+					  struct task_struct *tsk);
 extern void free_uts_ns(struct kref *kref);
 
 static inline void put_uts_ns(struct uts_namespace *ns)
@@ -70,12 +70,12 @@ static inline void put_uts_ns(struct uts_namespace *ns)
 }
 
 static inline struct uts_namespace *copy_utsname(unsigned long flags,
-					struct uts_namespace *ns)
+						 struct task_struct *tsk)
 {
 	if (flags & CLONE_NEWUTS)
 		return ERR_PTR(-EINVAL);
 
-	return ns;
+	return tsk->nsproxy->uts_ns;
 }
 #endif
 
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index b6dbff2..ac8a56e 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -69,16 +69,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 		goto out_ns;
 	}
 
-	new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
+	new_nsp->uts_ns = copy_utsname(flags, tsk);
 	if (IS_ERR(new_nsp->uts_ns)) {
 		err = PTR_ERR(new_nsp->uts_ns);
 		goto out_uts;
 	}
-	if (new_nsp->uts_ns != tsk->nsproxy->uts_ns) {
-		put_user_ns(new_nsp->uts_ns->user_ns);
-		new_nsp->uts_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;
-		get_user_ns(new_nsp->uts_ns->user_ns);
-	}
 
 	new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
 	if (IS_ERR(new_nsp->ipc_ns)) {
diff --git a/kernel/utsname.c b/kernel/utsname.c
index a7b3a8d..4464617 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -31,7 +31,8 @@ static struct uts_namespace *create_uts_ns(void)
  * @old_ns: namespace to clone
  * Return NULL on error (failure to kmalloc), new ns otherwise
  */
-static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
+static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
+					  struct uts_namespace *old_ns)
 {
 	struct uts_namespace *ns;
 
@@ -41,8 +42,7 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
 
 	down_read(&uts_sem);
 	memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
-	ns->user_ns = old_ns->user_ns;
-	get_user_ns(ns->user_ns);
+	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
 	up_read(&uts_sem);
 	return ns;
 }
@@ -53,8 +53,10 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
  * utsname of this process won't be seen by parent, and vice
  * versa.
  */
-struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *old_ns)
+struct uts_namespace *copy_utsname(unsigned long flags,
+				   struct task_struct *tsk)
 {
+	struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
 	struct uts_namespace *new_ns;
 
 	BUG_ON(!old_ns);
@@ -63,7 +65,7 @@ struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *ol
 	if (!(flags & CLONE_NEWUTS))
 		return old_ns;
 
-	new_ns = clone_uts_ns(old_ns);
+	new_ns = clone_uts_ns(tsk, old_ns);
 
 	put_uts_ns(old_ns);
 	return new_ns;
-- 
1.7.0.4

Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[Daniel Lezcano]

On 02/24/2011 01:21 AM, Serge E. Hallyn wrote:
> To do so we need to pass in the task_struct who'll get the utsname,
> so we can get its user_ns.
>
> Changelog:
> 	Feb 23: As per Oleg's coment, just pass in tsk.
>
> Signed-off-by: Serge E. Hallyn<serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>

Acked-by: Daniel Lezcano <daniel.lezcano-GANU6spQydw@public.gmane.org>

Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[Daniel Lezcano]

On 02/24/2011 01:21 AM, Serge E. Hallyn wrote:
> To do so we need to pass in the task_struct who'll get the utsname,
> so we can get its user_ns.
>
> Changelog:
> 	Feb 23: As per Oleg's coment, just pass in tsk.
>
> Signed-off-by: Serge E. Hallyn<serge.hallyn@canonical.com>

Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>

[PATCH 5/4] Clean up capability.h and capability.c

[Serge E. Hallyn]

Convert macros to functions to let type safety do its thing.  Switch
some functions from ints to more appropriate bool.  Move all forward
declarations together to top of the #ifdef __KERNEL__ section.  Use
kernel-doc format for comments.

Some macros couldn't be converted because they use functions from
security.h which sometimes are extern and sometimes static inline,
and we don't want to #include security.h in capability.h.

Also add a real current_user_ns function (and convert the existing
macro to _current_user_ns() so we can use it in capability.h
without #including cred.h.

Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com>
---
 include/linux/capability.h |   38 ++++++++++++++++++++++++++------------
 include/linux/cred.h       |    4 +++-
 kernel/capability.c        |   20 ++++++++++++--------
 kernel/cred.c              |    5 +++++
 4 files changed, 46 insertions(+), 21 deletions(-)

diff --git a/include/linux/capability.h b/include/linux/capability.h
index bc0f262..688462f 100644
--- a/include/linux/capability.h
+++ b/include/linux/capability.h
@@ -368,6 +368,17 @@ struct cpu_vfs_cap_data {
 
 #ifdef __KERNEL__
 
+struct dentry;
+struct user_namespace;
+
+extern struct user_namespace init_user_ns;
+
+struct user_namespace *current_user_ns(void);
+
+extern const kernel_cap_t __cap_empty_set;
+extern const kernel_cap_t __cap_full_set;
+extern const kernel_cap_t __cap_init_eff_set;
+
 /*
  * Internal kernel functions only
  */
@@ -530,10 +541,6 @@ static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
 			   cap_intersect(permitted, __cap_nfsd_set));
 }
 
-extern const kernel_cap_t __cap_empty_set;
-extern const kernel_cap_t __cap_full_set;
-extern const kernel_cap_t __cap_init_eff_set;
-
 /**
  * has_capability - Determine if a task has a superior capability available
  * @t: The task in question
@@ -560,18 +567,25 @@ extern const kernel_cap_t __cap_init_eff_set;
  * Note that this does not set PF_SUPERPRIV on the task.
  */
 #define has_capability_noaudit(t, cap) \
-	(security_real_capable_noaudit((t), &init_user_ns, (cap)) == 0)
+       (security_real_capable_noaudit((t), &init_user_ns, (cap)) == 0)
 
-struct user_namespace;
-extern struct user_namespace init_user_ns;
-extern int capable(int cap);
-extern int ns_capable(struct user_namespace *ns, int cap);
-extern int task_ns_capable(struct task_struct *t, int cap);
+extern bool capable(int cap);
+extern bool ns_capable(struct user_namespace *ns, int cap);
+extern bool task_ns_capable(struct task_struct *t, int cap);
 
-#define nsown_capable(cap) (ns_capable(current_user_ns(), (cap)))
+/**
+ * nsown_capable - Check superior capability to one's own user_ns
+ * @cap: The capability in question
+ *
+ * Return true if the current task has the given superior capability
+ * targeted at its own user namespace.
+ */
+static inline bool nsown_capable(int cap)
+{
+	return ns_capable(current_user_ns(), cap);
+}
 
 /* audit system wants to get cap info from files as well */
-struct dentry;
 extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
 
 #endif /* __KERNEL__ */
diff --git a/include/linux/cred.h b/include/linux/cred.h
index 4aaeab3..9aeeb0b 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -354,9 +354,11 @@ static inline void put_cred(const struct cred *_cred)
 #define current_fsgid() 	(current_cred_xxx(fsgid))
 #define current_cap()		(current_cred_xxx(cap_effective))
 #define current_user()		(current_cred_xxx(user))
-#define current_user_ns()	(current_cred_xxx(user)->user_ns)
+#define _current_user_ns()	(current_cred_xxx(user)->user_ns)
 #define current_security()	(current_cred_xxx(security))
 
+extern struct user_namespace *current_user_ns(void);
+
 #define current_uid_gid(_uid, _gid)		\
 do {						\
 	const struct cred *__cred;		\
diff --git a/kernel/capability.c b/kernel/capability.c
index 916658c..0a3d2c8 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -300,7 +300,7 @@ error:
  * This sets PF_SUPERPRIV on the task if the capability is available on the
  * assumption that it's about to be used.
  */
-int capable(int cap)
+bool capable(int cap)
 {
 	return ns_capable(&init_user_ns, cap);
 }
@@ -317,7 +317,7 @@ EXPORT_SYMBOL(capable);
  * This sets PF_SUPERPRIV on the task if the capability is available on the
  * assumption that it's about to be used.
  */
-int ns_capable(struct user_namespace *ns, int cap)
+bool ns_capable(struct user_namespace *ns, int cap)
 {
 	if (unlikely(!cap_valid(cap))) {
 		printk(KERN_CRIT "capable() called with invalid cap=%u\n", cap);
@@ -326,17 +326,21 @@ int ns_capable(struct user_namespace *ns, int cap)
 
 	if (security_capable(ns, current_cred(), cap) == 0) {
 		current->flags |= PF_SUPERPRIV;
-		return 1;
+		return true;
 	}
-	return 0;
+	return false;
 }
 EXPORT_SYMBOL(ns_capable);
 
-/*
- * does current have capability 'cap' to the user namespace of task
- * 't'.  Return true if it does, false otherwise.
+/**
+ * task_ns_capable - Determine whether current task has a superior
+ * capability targeted at a specific task's user namespace.
+ * @t: The task whose user namespace is targeted.
+ * @cap: The capability in question.
+ *
+ *  Return true if it does, false otherwise.
  */
-int task_ns_capable(struct task_struct *t, int cap)
+bool task_ns_capable(struct task_struct *t, int cap)
 {
 	return ns_capable(task_cred_xxx(t, user)->user_ns, cap);
 }
diff --git a/kernel/cred.c b/kernel/cred.c
index 3a9d6dd..e447fa2 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -741,6 +741,11 @@ int set_create_files_as(struct cred *new, struct inode *inode)
 }
 EXPORT_SYMBOL(set_create_files_as);
 
+struct user_namespace *current_user_ns(void)
+{
+	return _current_user_ns();
+}
+
 #ifdef CONFIG_DEBUG_CREDENTIALS
 
 bool creds_are_invalid(const struct cred *cred)
-- 
1.7.0.4

Re: [PATCH 5/4] Clean up capability.h and capability.c

[Daniel Lezcano]

On 02/24/2011 01:22 AM, Serge E. Hallyn wrote:
> Convert macros to functions to let type safety do its thing.  Switch
> some functions from ints to more appropriate bool.  Move all forward
> declarations together to top of the #ifdef __KERNEL__ section.  Use
> kernel-doc format for comments.
>
> Some macros couldn't be converted because they use functions from
> security.h which sometimes are extern and sometimes static inline,
> and we don't want to #include security.h in capability.h.
>
> Also add a real current_user_ns function (and convert the existing
> macro to _current_user_ns() so we can use it in capability.h
> without #including cred.h.
>
> Signed-off-by: Serge E. Hallyn<serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
> ---

Acked-by: Daniel Lezcano <daniel.lezcano-GANU6spQydw@public.gmane.org>

Re: [PATCH 5/4] Clean up capability.h and capability.c

[Daniel Lezcano]

On 02/24/2011 01:22 AM, Serge E. Hallyn wrote:
> Convert macros to functions to let type safety do its thing.  Switch
> some functions from ints to more appropriate bool.  Move all forward
> declarations together to top of the #ifdef __KERNEL__ section.  Use
> kernel-doc format for comments.
>
> Some macros couldn't be converted because they use functions from
> security.h which sometimes are extern and sometimes static inline,
> and we don't want to #include security.h in capability.h.
>
> Also add a real current_user_ns function (and convert the existing
> macro to _current_user_ns() so we can use it in capability.h
> without #including cred.h.
>
> Signed-off-by: Serge E. Hallyn<serge.hallyn@canonical.com>
> ---

Acked-by: Daniel Lezcano <daniel.lezcano@free.fr>

[PATCH 2/4] userns: let copy_ipcs handle setting ipc_ns->user_ns

[Serge E. Hallyn]

To do that, we have to pass in the task_struct of the task which
will own the ipc_ns, so we can assign its user_ns.

Signed-off-by: Serge E. Hallyn <serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
---
 include/linux/ipc_namespace.h |    8 +++++---
 ipc/namespace.c               |   12 +++++++-----
 kernel/nsproxy.c              |    7 +------
 3 files changed, 13 insertions(+), 14 deletions(-)

diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index 46d2eb4..9974429 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -92,7 +92,8 @@ static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
 #endif
 
 #if defined(CONFIG_IPC_NS)
-extern struct ipc_namespace *copy_ipcs(unsigned long flags,
+extern struct ipc_namespace *copy_ipcs(struct task_struct *tsk,
+				       unsigned long flags,
 				       struct ipc_namespace *ns);
 static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
 {
@@ -103,8 +104,9 @@ static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
 
 extern void put_ipc_ns(struct ipc_namespace *ns);
 #else
-static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
-		struct ipc_namespace *ns)
+static inline struct ipc_namespace *copy_ipcs(struct task_struct *tsk,
+					      unsigned long flags,
+					      struct ipc_namespace *ns)
 {
 	if (flags & CLONE_NEWIPC)
 		return ERR_PTR(-EINVAL);
diff --git a/ipc/namespace.c b/ipc/namespace.c
index aa18899..ee84882 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -15,7 +15,8 @@
 
 #include "util.h"
 
-static struct ipc_namespace *create_ipc_ns(struct ipc_namespace *old_ns)
+static struct ipc_namespace *create_ipc_ns(struct task_struct *tsk,
+					   struct ipc_namespace *old_ns)
 {
 	struct ipc_namespace *ns;
 	int err;
@@ -44,17 +45,18 @@ static struct ipc_namespace *create_ipc_ns(struct ipc_namespace *old_ns)
 	ipcns_notify(IPCNS_CREATED);
 	register_ipcns_notifier(ns);
 
-	ns->user_ns = old_ns->user_ns;
-	get_user_ns(ns->user_ns);
+	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
 
 	return ns;
 }
 
-struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns)
+struct ipc_namespace *copy_ipcs(struct task_struct *tsk,
+				unsigned long flags,
+				struct ipc_namespace *ns)
 {
 	if (!(flags & CLONE_NEWIPC))
 		return get_ipc_ns(ns);
-	return create_ipc_ns(ns);
+	return create_ipc_ns(tsk, ns);
 }
 
 /*
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index ffa6b67..b905ecc 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -75,16 +75,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 		goto out_uts;
 	}
 
-	new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
+	new_nsp->ipc_ns = copy_ipcs(tsk, flags, tsk->nsproxy->ipc_ns);
 	if (IS_ERR(new_nsp->ipc_ns)) {
 		err = PTR_ERR(new_nsp->ipc_ns);
 		goto out_ipc;
 	}
-	if (new_nsp->ipc_ns != tsk->nsproxy->ipc_ns) {
-		put_user_ns(new_nsp->ipc_ns->user_ns);
-		new_nsp->ipc_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;
-		get_user_ns(new_nsp->ipc_ns->user_ns);
-	}
 
 	new_nsp->pid_ns = copy_pid_ns(flags, task_active_pid_ns(tsk));
 	if (IS_ERR(new_nsp->pid_ns)) {
-- 
1.7.0.4

[PATCH 3/4] Add the required user_ns parameter to security_capable

[Serge E. Hallyn]

Fixes a compile failure.

Signed-off-by: Serge E. Hallyn <serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
---
 drivers/pci/pci-sysfs.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index ea25e5b..90a6b04 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -369,7 +369,7 @@ pci_read_config(struct file *filp, struct kobject *kobj,
 	u8 *data = (u8*) buf;
 
 	/* Several chips lock up trying to read undefined config space */
-	if (security_capable(filp->f_cred, CAP_SYS_ADMIN) == 0) {
+	if (security_capable(&init_user_ns, filp->f_cred, CAP_SYS_ADMIN) == 0) {
 		size = dev->cfg_size;
 	} else if (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS) {
 		size = 128;
-- 
1.7.0.4

[PATCH 4/4] userns: uts and ipc: fix checkpatch warning

[Serge E. Hallyn]

As pointed out by Andrew Morton (and checkpatch), init/version.c
(and ipc/msgutil.c) should not have an extern declaration for
init_user_ns.  Instead, move those to ipc_namespace.h and utsname.h.

Signed-off-by: Serge E. Hallyn <serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
---
 include/linux/ipc_namespace.h |    3 ++-
 include/linux/utsname.h       |    1 +
 init/version.c                |    1 -
 ipc/msgutil.c                 |    2 --
 4 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index 9974429..ebd4a93 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -15,6 +15,8 @@
 
 #define IPCNS_CALLBACK_PRI 0
 
+struct user_namespace;
+extern struct user_namespace init_user_ns;
 
 struct ipc_ids {
 	int in_use;
@@ -24,7 +26,6 @@ struct ipc_ids {
 	struct idr ipcs_idr;
 };
 
-struct user_namespace;
 struct ipc_namespace {
 	atomic_t	count;
 	struct ipc_ids	ids[3];
diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 165b17b..69957ca 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -38,6 +38,7 @@ struct new_utsname {
 #include <linux/err.h>
 
 struct user_namespace;
+extern struct user_namespace init_user_ns;
 
 struct uts_namespace {
 	struct kref kref;
diff --git a/init/version.c b/init/version.c
index 97bb86f..86fe0cc 100644
--- a/init/version.c
+++ b/init/version.c
@@ -21,7 +21,6 @@ extern int version_string(LINUX_VERSION_CODE);
 int version_string(LINUX_VERSION_CODE);
 #endif
 
-extern struct user_namespace init_user_ns;
 struct uts_namespace init_uts_ns = {
 	.kref = {
 		.refcount	= ATOMIC_INIT(2),
diff --git a/ipc/msgutil.c b/ipc/msgutil.c
index d91ff4b..8b5ce5d 100644
--- a/ipc/msgutil.c
+++ b/ipc/msgutil.c
@@ -20,8 +20,6 @@
 
 DEFINE_SPINLOCK(mq_lock);
 
-extern struct user_namespace init_user_ns;
-
 /*
  * The next 2 defines are here bc this is the only file
  * compiled when either CONFIG_SYSVIPC and CONFIG_POSIX_MQUEUE
-- 
1.7.0.4

Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[Daniel Lezcano]

On 02/21/2011 05:01 AM, Serge E. Hallyn wrote:
> To do so we need to pass in the task_struct who'll get the utsname,
> so we can get its user_ns.
>
> Signed-off-by: Serge E. Hallyn<serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
> ---


>   include/linux/utsname.h |   10 ++++++----
>   kernel/nsproxy.c        |    7 +------
>   kernel/utsname.c        |   12 +++++++-----
>   3 files changed, 14 insertions(+), 15 deletions(-)
>
> diff --git a/include/linux/utsname.h b/include/linux/utsname.h
> index 85171be..165b17b 100644
> --- a/include/linux/utsname.h
> +++ b/include/linux/utsname.h
> @@ -52,8 +52,9 @@ static inline void get_uts_ns(struct uts_namespace *ns)
>   	kref_get(&ns->kref);
>   }
>
> -extern struct uts_namespace *copy_utsname(unsigned long flags,
> -					struct uts_namespace *ns);
> +extern struct uts_namespace *copy_utsname(struct task_struct *tsk,
> +					  unsigned long flags,
> +					  struct uts_namespace *ns);

Why don't we pass 'user_ns' instead of 'tsk' ? that will look 
semantically clearer for the caller no ?
(example below).

>   extern void free_uts_ns(struct kref *kref);
>
>   static inline void put_uts_ns(struct uts_namespace *ns)
> @@ -69,8 +70,9 @@ static inline void put_uts_ns(struct uts_namespace *ns)
>   {
>   }
>
> -static inline struct uts_namespace *copy_utsname(unsigned long flags,
> -					struct uts_namespace *ns)
> +static inline struct uts_namespace *copy_utsname(struct task_struct *tsk,
> +						 unsigned long flags,
> +						 struct uts_namespace *ns)
>   {
>   	if (flags&  CLONE_NEWUTS)
>   		return ERR_PTR(-EINVAL);
> diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
> index b6dbff2..ffa6b67 100644
> --- a/kernel/nsproxy.c
> +++ b/kernel/nsproxy.c
> @@ -69,16 +69,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
>   		goto out_ns;
>   	}
>
> -	new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
> +	new_nsp->uts_ns = copy_utsname(tsk, flags, tsk->nsproxy->uts_ns);
>   	if (IS_ERR(new_nsp->uts_ns)) {
>   		err = PTR_ERR(new_nsp->uts_ns);
>   		goto out_uts;
>   	}

...

new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns, task_cred_xxx(tsk, user)->user_ns);

...

> -	if (new_nsp->uts_ns != tsk->nsproxy->uts_ns) {
> -		put_user_ns(new_nsp->uts_ns->user_ns);
> -		new_nsp->uts_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;
> -		get_user_ns(new_nsp->uts_ns->user_ns);
> -	}
>
>   	new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
>   	if (IS_ERR(new_nsp->ipc_ns)) {
> diff --git a/kernel/utsname.c b/kernel/utsname.c
> index a7b3a8d..9462580 100644
> --- a/kernel/utsname.c
> +++ b/kernel/utsname.c
> @@ -31,7 +31,8 @@ static struct uts_namespace *create_uts_ns(void)
>    * @old_ns: namespace to clone
>    * Return NULL on error (failure to kmalloc), new ns otherwise
>    */
> -static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
> +static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
> +					  struct uts_namespace *old_ns)
>   {
>   	struct uts_namespace *ns;
>
> @@ -41,8 +42,7 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
>
>   	down_read(&uts_sem);
>   	memcpy(&ns->name,&old_ns->name, sizeof(ns->name));
> -	ns->user_ns = old_ns->user_ns;
> -	get_user_ns(ns->user_ns);
> +	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
>   	up_read(&uts_sem);
>   	return ns;
>   }
> @@ -53,7 +53,9 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
>    * utsname of this process won't be seen by parent, and vice
>    * versa.
>    */
> -struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *old_ns)
> +struct uts_namespace *copy_utsname(struct task_struct *tsk,
> +				   unsigned long flags,
> +				   struct uts_namespace *old_ns)
>   {
>   	struct uts_namespace *new_ns;
>
> @@ -63,7 +65,7 @@ struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *ol
>   	if (!(flags&  CLONE_NEWUTS))
>   		return old_ns;
>
> -	new_ns = clone_uts_ns(old_ns);
> +	new_ns = clone_uts_ns(tsk, old_ns);
>
>   	put_uts_ns(old_ns);
>   	return new_ns;

[PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[Serge E. Hallyn]

To do so we need to pass in the task_struct who'll get the utsname,
so we can get its user_ns.

Changelog:
	Feb 23: As per Oleg's coment, just pass in tsk.

Signed-off-by: Serge E. Hallyn <serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
---
 include/linux/utsname.h |    6 +++---
 kernel/nsproxy.c        |    7 +------
 kernel/utsname.c        |   12 +++++++-----
 3 files changed, 11 insertions(+), 14 deletions(-)

diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 85171be..21b4566 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -53,7 +53,7 @@ static inline void get_uts_ns(struct uts_namespace *ns)
 }
 
 extern struct uts_namespace *copy_utsname(unsigned long flags,
-					struct uts_namespace *ns);
+					  struct task_struct *tsk);
 extern void free_uts_ns(struct kref *kref);
 
 static inline void put_uts_ns(struct uts_namespace *ns)
@@ -70,12 +70,12 @@ static inline void put_uts_ns(struct uts_namespace *ns)
 }
 
 static inline struct uts_namespace *copy_utsname(unsigned long flags,
-					struct uts_namespace *ns)
+						 struct task_struct *tsk)
 {
 	if (flags & CLONE_NEWUTS)
 		return ERR_PTR(-EINVAL);
 
-	return ns;
+	return tsk->nsproxy->uts_ns;
 }
 #endif
 
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index b6dbff2..ac8a56e 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -69,16 +69,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 		goto out_ns;
 	}
 
-	new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
+	new_nsp->uts_ns = copy_utsname(flags, tsk);
 	if (IS_ERR(new_nsp->uts_ns)) {
 		err = PTR_ERR(new_nsp->uts_ns);
 		goto out_uts;
 	}
-	if (new_nsp->uts_ns != tsk->nsproxy->uts_ns) {
-		put_user_ns(new_nsp->uts_ns->user_ns);
-		new_nsp->uts_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;
-		get_user_ns(new_nsp->uts_ns->user_ns);
-	}
 
 	new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
 	if (IS_ERR(new_nsp->ipc_ns)) {
diff --git a/kernel/utsname.c b/kernel/utsname.c
index a7b3a8d..4464617 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -31,7 +31,8 @@ static struct uts_namespace *create_uts_ns(void)
  * @old_ns: namespace to clone
  * Return NULL on error (failure to kmalloc), new ns otherwise
  */
-static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
+static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
+					  struct uts_namespace *old_ns)
 {
 	struct uts_namespace *ns;
 
@@ -41,8 +42,7 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
 
 	down_read(&uts_sem);
 	memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
-	ns->user_ns = old_ns->user_ns;
-	get_user_ns(ns->user_ns);
+	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
 	up_read(&uts_sem);
 	return ns;
 }
@@ -53,8 +53,10 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
  * utsname of this process won't be seen by parent, and vice
  * versa.
  */
-struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *old_ns)
+struct uts_namespace *copy_utsname(unsigned long flags,
+				   struct task_struct *tsk)
 {
+	struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
 	struct uts_namespace *new_ns;
 
 	BUG_ON(!old_ns);
@@ -63,7 +65,7 @@ struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *ol
 	if (!(flags & CLONE_NEWUTS))
 		return old_ns;
 
-	new_ns = clone_uts_ns(old_ns);
+	new_ns = clone_uts_ns(tsk, old_ns);
 
 	put_uts_ns(old_ns);
 	return new_ns;
-- 
1.7.0.4

[PATCH 5/4] Clean up capability.h and capability.c

[Serge E. Hallyn]

Convert macros to functions to let type safety do its thing.  Switch
some functions from ints to more appropriate bool.  Move all forward
declarations together to top of the #ifdef __KERNEL__ section.  Use
kernel-doc format for comments.

Some macros couldn't be converted because they use functions from
security.h which sometimes are extern and sometimes static inline,
and we don't want to #include security.h in capability.h.

Also add a real current_user_ns function (and convert the existing
macro to _current_user_ns() so we can use it in capability.h
without #including cred.h.

Signed-off-by: Serge E. Hallyn <serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
---
 include/linux/capability.h |   38 ++++++++++++++++++++++++++------------
 include/linux/cred.h       |    4 +++-
 kernel/capability.c        |   20 ++++++++++++--------
 kernel/cred.c              |    5 +++++
 4 files changed, 46 insertions(+), 21 deletions(-)

diff --git a/include/linux/capability.h b/include/linux/capability.h
index bc0f262..688462f 100644
--- a/include/linux/capability.h
+++ b/include/linux/capability.h
@@ -368,6 +368,17 @@ struct cpu_vfs_cap_data {
 
 #ifdef __KERNEL__
 
+struct dentry;
+struct user_namespace;
+
+extern struct user_namespace init_user_ns;
+
+struct user_namespace *current_user_ns(void);
+
+extern const kernel_cap_t __cap_empty_set;
+extern const kernel_cap_t __cap_full_set;
+extern const kernel_cap_t __cap_init_eff_set;
+
 /*
  * Internal kernel functions only
  */
@@ -530,10 +541,6 @@ static inline kernel_cap_t cap_raise_nfsd_set(const kernel_cap_t a,
 			   cap_intersect(permitted, __cap_nfsd_set));
 }
 
-extern const kernel_cap_t __cap_empty_set;
-extern const kernel_cap_t __cap_full_set;
-extern const kernel_cap_t __cap_init_eff_set;
-
 /**
  * has_capability - Determine if a task has a superior capability available
  * @t: The task in question
@@ -560,18 +567,25 @@ extern const kernel_cap_t __cap_init_eff_set;
  * Note that this does not set PF_SUPERPRIV on the task.
  */
 #define has_capability_noaudit(t, cap) \
-	(security_real_capable_noaudit((t), &init_user_ns, (cap)) == 0)
+       (security_real_capable_noaudit((t), &init_user_ns, (cap)) == 0)
 
-struct user_namespace;
-extern struct user_namespace init_user_ns;
-extern int capable(int cap);
-extern int ns_capable(struct user_namespace *ns, int cap);
-extern int task_ns_capable(struct task_struct *t, int cap);
+extern bool capable(int cap);
+extern bool ns_capable(struct user_namespace *ns, int cap);
+extern bool task_ns_capable(struct task_struct *t, int cap);
 
-#define nsown_capable(cap) (ns_capable(current_user_ns(), (cap)))
+/**
+ * nsown_capable - Check superior capability to one's own user_ns
+ * @cap: The capability in question
+ *
+ * Return true if the current task has the given superior capability
+ * targeted at its own user namespace.
+ */
+static inline bool nsown_capable(int cap)
+{
+	return ns_capable(current_user_ns(), cap);
+}
 
 /* audit system wants to get cap info from files as well */
-struct dentry;
 extern int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps);
 
 #endif /* __KERNEL__ */
diff --git a/include/linux/cred.h b/include/linux/cred.h
index 4aaeab3..9aeeb0b 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -354,9 +354,11 @@ static inline void put_cred(const struct cred *_cred)
 #define current_fsgid() 	(current_cred_xxx(fsgid))
 #define current_cap()		(current_cred_xxx(cap_effective))
 #define current_user()		(current_cred_xxx(user))
-#define current_user_ns()	(current_cred_xxx(user)->user_ns)
+#define _current_user_ns()	(current_cred_xxx(user)->user_ns)
 #define current_security()	(current_cred_xxx(security))
 
+extern struct user_namespace *current_user_ns(void);
+
 #define current_uid_gid(_uid, _gid)		\
 do {						\
 	const struct cred *__cred;		\
diff --git a/kernel/capability.c b/kernel/capability.c
index 916658c..0a3d2c8 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -300,7 +300,7 @@ error:
  * This sets PF_SUPERPRIV on the task if the capability is available on the
  * assumption that it's about to be used.
  */
-int capable(int cap)
+bool capable(int cap)
 {
 	return ns_capable(&init_user_ns, cap);
 }
@@ -317,7 +317,7 @@ EXPORT_SYMBOL(capable);
  * This sets PF_SUPERPRIV on the task if the capability is available on the
  * assumption that it's about to be used.
  */
-int ns_capable(struct user_namespace *ns, int cap)
+bool ns_capable(struct user_namespace *ns, int cap)
 {
 	if (unlikely(!cap_valid(cap))) {
 		printk(KERN_CRIT "capable() called with invalid cap=%u\n", cap);
@@ -326,17 +326,21 @@ int ns_capable(struct user_namespace *ns, int cap)
 
 	if (security_capable(ns, current_cred(), cap) == 0) {
 		current->flags |= PF_SUPERPRIV;
-		return 1;
+		return true;
 	}
-	return 0;
+	return false;
 }
 EXPORT_SYMBOL(ns_capable);
 
-/*
- * does current have capability 'cap' to the user namespace of task
- * 't'.  Return true if it does, false otherwise.
+/**
+ * task_ns_capable - Determine whether current task has a superior
+ * capability targeted at a specific task's user namespace.
+ * @t: The task whose user namespace is targeted.
+ * @cap: The capability in question.
+ *
+ *  Return true if it does, false otherwise.
  */
-int task_ns_capable(struct task_struct *t, int cap)
+bool task_ns_capable(struct task_struct *t, int cap)
 {
 	return ns_capable(task_cred_xxx(t, user)->user_ns, cap);
 }
diff --git a/kernel/cred.c b/kernel/cred.c
index 3a9d6dd..e447fa2 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -741,6 +741,11 @@ int set_create_files_as(struct cred *new, struct inode *inode)
 }
 EXPORT_SYMBOL(set_create_files_as);
 
+struct user_namespace *current_user_ns(void)
+{
+	return _current_user_ns();
+}
+
 #ifdef CONFIG_DEBUG_CREDENTIALS
 
 bool creds_are_invalid(const struct cred *cred)
-- 
1.7.0.4

[PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns

[Serge E. Hallyn]

To do so we need to pass in the task_struct who'll get the utsname,
so we can get its user_ns.

Signed-off-by: Serge E. Hallyn <serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>
---
 include/linux/utsname.h |   10 ++++++----
 kernel/nsproxy.c        |    7 +------
 kernel/utsname.c        |   12 +++++++-----
 3 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 85171be..165b17b 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -52,8 +52,9 @@ static inline void get_uts_ns(struct uts_namespace *ns)
 	kref_get(&ns->kref);
 }
 
-extern struct uts_namespace *copy_utsname(unsigned long flags,
-					struct uts_namespace *ns);
+extern struct uts_namespace *copy_utsname(struct task_struct *tsk,
+					  unsigned long flags,
+					  struct uts_namespace *ns);
 extern void free_uts_ns(struct kref *kref);
 
 static inline void put_uts_ns(struct uts_namespace *ns)
@@ -69,8 +70,9 @@ static inline void put_uts_ns(struct uts_namespace *ns)
 {
 }
 
-static inline struct uts_namespace *copy_utsname(unsigned long flags,
-					struct uts_namespace *ns)
+static inline struct uts_namespace *copy_utsname(struct task_struct *tsk,
+						 unsigned long flags,
+						 struct uts_namespace *ns)
 {
 	if (flags & CLONE_NEWUTS)
 		return ERR_PTR(-EINVAL);
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index b6dbff2..ffa6b67 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -69,16 +69,11 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
 		goto out_ns;
 	}
 
-	new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
+	new_nsp->uts_ns = copy_utsname(tsk, flags, tsk->nsproxy->uts_ns);
 	if (IS_ERR(new_nsp->uts_ns)) {
 		err = PTR_ERR(new_nsp->uts_ns);
 		goto out_uts;
 	}
-	if (new_nsp->uts_ns != tsk->nsproxy->uts_ns) {
-		put_user_ns(new_nsp->uts_ns->user_ns);
-		new_nsp->uts_ns->user_ns = task_cred_xxx(tsk, user)->user_ns;
-		get_user_ns(new_nsp->uts_ns->user_ns);
-	}
 
 	new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
 	if (IS_ERR(new_nsp->ipc_ns)) {
diff --git a/kernel/utsname.c b/kernel/utsname.c
index a7b3a8d..9462580 100644
--- a/kernel/utsname.c
+++ b/kernel/utsname.c
@@ -31,7 +31,8 @@ static struct uts_namespace *create_uts_ns(void)
  * @old_ns: namespace to clone
  * Return NULL on error (failure to kmalloc), new ns otherwise
  */
-static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
+static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
+					  struct uts_namespace *old_ns)
 {
 	struct uts_namespace *ns;
 
@@ -41,8 +42,7 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
 
 	down_read(&uts_sem);
 	memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
-	ns->user_ns = old_ns->user_ns;
-	get_user_ns(ns->user_ns);
+	ns->user_ns = get_user_ns(task_cred_xxx(tsk, user)->user_ns);
 	up_read(&uts_sem);
 	return ns;
 }
@@ -53,7 +53,9 @@ static struct uts_namespace *clone_uts_ns(struct uts_namespace *old_ns)
  * utsname of this process won't be seen by parent, and vice
  * versa.
  */
-struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *old_ns)
+struct uts_namespace *copy_utsname(struct task_struct *tsk,
+				   unsigned long flags,
+				   struct uts_namespace *old_ns)
 {
 	struct uts_namespace *new_ns;
 
@@ -63,7 +65,7 @@ struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *ol
 	if (!(flags & CLONE_NEWUTS))
 		return old_ns;
 
-	new_ns = clone_uts_ns(old_ns);
+	new_ns = clone_uts_ns(tsk, old_ns);
 
 	put_uts_ns(old_ns);
 	return new_ns;
-- 
1.7.0.4