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SubjectRe: PATCH -mm] fix create_new_namespaces() return value
Badari Pulavarty wrote:
>
>
> Cedric Le Goater wrote:
>
>> The following patch modifies create_new_namespaces() to also use the
>> errors returned by the copy_*_ns routines and not to systematically
>> return ENOMEM.
>>
>
> In my initial version, I did same. It doesn't work :(
>
> copy_*_ns() routines doesn't return any errors. All they return is NULL
> in case of a
> failure + with the exception of copy_mnt_ns, there are no other failure
> cases.
> So, there is no way to find out why the copy_*_ns() routines failed from
> create_new_namespaces().
> If you really really want to do this, change all copy_*_ns() routines to
> returns meaningful
> errors instead of NULL.

Here's a second try to apply on top of -mm branch,

Thanks for the review Badari.

C.


The following patch modifies create_new_namespaces() to also use the
errors returned by the copy_*_ns routines and not to systematically
return ENOMEM.

Changes since [try #1]:
- fixed return values of clone_*_ns() routines

Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Cc: Pavel Emelianov <xemul@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Eric W. Biederman <ebiederm@xmission.com>
---
fs/namespace.c | 4 ++--
kernel/nsproxy.c | 23 +++++++++++++++++------
kernel/user_namespace.c | 6 +++---
kernel/utsname.c | 10 ++++++----
4 files changed, 28 insertions(+), 15 deletions(-)

Index: 2.6.22-rc4-mm2/kernel/nsproxy.c
===================================================================
--- 2.6.22-rc4-mm2.orig/kernel/nsproxy.c
+++ 2.6.22-rc4-mm2/kernel/nsproxy.c
@@ -58,30 +58,41 @@ static struct nsproxy *create_new_namesp
struct fs_struct *new_fs)
{
struct nsproxy *new_nsp;
+ int err;

new_nsp = clone_nsproxy(tsk->nsproxy);
if (!new_nsp)
return ERR_PTR(-ENOMEM);

new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);
- if (IS_ERR(new_nsp->mnt_ns))
+ if (IS_ERR(new_nsp->mnt_ns)) {
+ err = PTR_ERR(new_nsp->mnt_ns);
goto out_ns;
+ }

new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
- if (IS_ERR(new_nsp->uts_ns))
+ if (IS_ERR(new_nsp->uts_ns)) {
+ err = PTR_ERR(new_nsp->uts_ns);
goto out_uts;
+ }

new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
- if (IS_ERR(new_nsp->ipc_ns))
+ if (IS_ERR(new_nsp->ipc_ns)) {
+ err = PTR_ERR(new_nsp->ipc_ns);
goto out_ipc;
+ }

new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns);
- if (IS_ERR(new_nsp->pid_ns))
+ if (IS_ERR(new_nsp->pid_ns)) {
+ err = PTR_ERR(new_nsp->pid_ns);
goto out_pid;
+ }

new_nsp->user_ns = copy_user_ns(flags, tsk->nsproxy->user_ns);
- if (IS_ERR(new_nsp->user_ns))
+ if (IS_ERR(new_nsp->user_ns)) {
+ err = PTR_ERR(new_nsp->user_ns);
goto out_user;
+ }

return new_nsp;

@@ -99,7 +110,7 @@ out_uts:
put_mnt_ns(new_nsp->mnt_ns);
out_ns:
kfree(new_nsp);
- return ERR_PTR(-ENOMEM);
+ return ERR_PTR(err);
}

/*
Index: 2.6.22-rc4-mm2/fs/namespace.c
===================================================================
--- 2.6.22-rc4-mm2.orig/fs/namespace.c
+++ 2.6.22-rc4-mm2/fs/namespace.c
@@ -1599,7 +1599,7 @@ static struct mnt_namespace *dup_mnt_ns(

new_ns = kmalloc(sizeof(struct mnt_namespace), GFP_KERNEL);
if (!new_ns)
- return NULL;
+ return ERR_PTR(-ENOMEM);

atomic_set(&new_ns->count, 1);
INIT_LIST_HEAD(&new_ns->list);
@@ -1613,7 +1613,7 @@ static struct mnt_namespace *dup_mnt_ns(
if (IS_ERR(new_ns->root)) {
up_write(&namespace_sem);
kfree(new_ns);
- return NULL;
+ return ERR_PTR(-ENOMEM);;
}
spin_lock(&vfsmount_lock);
list_add_tail(&new_ns->list, &new_ns->root->mnt_list);
Index: 2.6.22-rc4-mm2/kernel/user_namespace.c
===================================================================
--- 2.6.22-rc4-mm2.orig/kernel/user_namespace.c
+++ 2.6.22-rc4-mm2/kernel/user_namespace.c
@@ -34,7 +34,7 @@ static struct user_namespace *clone_user

ns = kmalloc(sizeof(struct user_namespace), GFP_KERNEL);
if (!ns)
- return NULL;
+ return ERR_PTR(-ENOMEM);

kref_init(&ns->kref);

@@ -45,7 +45,7 @@ static struct user_namespace *clone_user
ns->root_user = alloc_uid(ns, 0);
if (!ns->root_user) {
kfree(ns);
- return NULL;
+ return ERR_PTR(-ENOMEM);
}

/* Reset current->user with a new one */
@@ -53,7 +53,7 @@ static struct user_namespace *clone_user
if (!new_user) {
free_uid(ns->root_user);
kfree(ns);
- return NULL;
+ return ERR_PTR(-ENOMEM);
}

switch_uid(new_user);
Index: 2.6.22-rc4-mm2/kernel/utsname.c
===================================================================
--- 2.6.22-rc4-mm2.orig/kernel/utsname.c
+++ 2.6.22-rc4-mm2/kernel/utsname.c
@@ -13,6 +13,7 @@
#include <linux/uts.h>
#include <linux/utsname.h>
#include <linux/version.h>
+#include <linux/err.h>

/*
* Clone a new ns copying an original utsname, setting refcount to 1
@@ -24,10 +25,11 @@ static struct uts_namespace *clone_uts_n
struct uts_namespace *ns;

ns = kmalloc(sizeof(struct uts_namespace), GFP_KERNEL);
- if (ns) {
- memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
- kref_init(&ns->kref);
- }
+ if (!ns)
+ return ERR_PTR(-ENOMEM);
+
+ memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
+ kref_init(&ns->kref);
return ns;
}

-
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