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[PATCH 1/4] userns: let clone_uts_ns() handle setting uts->user_ns [message #41797] Mon, 21 February 2011 04:01 Go to next message
serge is currently offline  serge
Messages: 72
Registered: January 2007
Member
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

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[PATCH 2/4] userns: let copy_ipcs handle setting ipc_ns-&gt;user_ns [message #41798 is a reply to message #41797] Mon, 21 February 2011 04:02 Go to previous messageGo to next message
serge is currently offline  serge
Messages: 72
Registered: January 2007
Member
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

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[PATCH 3/4] Add the required user_ns parameter to security_capable [message #41799 is a reply to message #41797] Mon, 21 February 2011 04:02 Go to previous messageGo to next message
serge is currently offline  serge
Messages: 72
Registered: January 2007
Member
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

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[PATCH 4/4] userns: uts and ipc: fix checkpatch warning [message #41800 is a reply to message #41797] Mon, 21 February 2011 04:05 Go to previous messageGo to next message
serge is currently offline  serge
Messages: 72
Registered: January 2007
Member
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

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Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts-&gt;user_ns [message #41802 is a reply to message #41797] Mon, 21 February 2011 10:03 Go to previous messageGo to next message
Daniel Lezcano is currently offline  Daniel Lezcano
Messages: 417
Registered: June 2006
Senior Member
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;

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Re: [PATCH 2/4] userns: let copy_ipcs handle setting ipc_ns-&gt;user_ns [message #41803 is a reply to message #41798] Mon, 21 February 2011 10:05 Go to previous messageGo to next message
Daniel Lezcano is currently offline  Daniel Lezcano
Messages: 417
Registered: June 2006
Senior Member
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
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Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts-&gt;user_ns [message #41806 is a reply to message #41802] Mon, 21 February 2011 13:41 Go to previous messageGo to next message
Oleg Nesterov is currently offline  Oleg Nesterov
Messages: 143
Registered: August 2006
Senior Member
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.

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Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts-&gt;user_ns [message #41807 is a reply to message #41806] Mon, 21 February 2011 13:58 Go to previous messageGo to next message
serge is currently offline  serge
Messages: 72
Registered: January 2007
Member
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
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Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts-&gt;user_ns [message #41808 is a reply to message #41807] Mon, 21 February 2011 14:23 Go to previous messageGo to next message
Daniel Lezcano is currently offline  Daniel Lezcano
Messages: 417
Registered: June 2006
Senior Member
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.

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[PATCH 1/4] userns: let clone_uts_ns() handle setting uts-&gt;user_ns [message #41871 is a reply to message #41797] Thu, 24 February 2011 00:21 Go to previous messageGo to next message
serge is currently offline  serge
Messages: 72
Registered: January 2007
Member
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

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[PATCH 2/4] userns: let copy_ipcs handle setting ipc_ns-&gt;user_ns [message #41872 is a reply to message #41798] Thu, 24 February 2011 00:22 Go to previous messageGo to next message
serge is currently offline  serge
Messages: 72
Registered: January 2007
Member
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

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[PATCH 5/4] Clean up capability.h and capability.c [message #41873 is a reply to message #41797] Thu, 24 February 2011 00:22 Go to previous messageGo to next message
serge is currently offline  serge
Messages: 72
Registered: January 2007
Member
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

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Re: [PATCH 1/4] userns: let clone_uts_ns() handle setting uts-&gt;user_ns [message #41890 is a reply to message #41871] Thu, 24 February 2011 09:54 Go to previous messageGo to next message
Daniel Lezcano is currently offline  Daniel Lezcano
Messages: 417
Registered: June 2006
Senior Member
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>

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Re: [PATCH 2/4] userns: let copy_ipcs handle setting ipc_ns-&gt;user_ns [message #41891 is a reply to message #41872] Thu, 24 February 2011 09:55 Go to previous messageGo to next message
Daniel Lezcano is currently offline  Daniel Lezcano
Messages: 417
Registered: June 2006
Senior Member
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>
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Re: [PATCH 5/4] Clean up capability.h and capability.c [message #41892 is a reply to message #41873] Thu, 24 February 2011 09:56 Go to previous message
Daniel Lezcano is currently offline  Daniel Lezcano
Messages: 417
Registered: June 2006
Senior Member
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>

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