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userns: Make create_new_namespaces take a user_ns parameter 

Modify create_new_namespaces to explicitly take a user namespace
parameter, instead of implicitly through the task_struct.

This allows an implementation of unshare(CLONE_NEWUSER) where
the new user namespace is not stored onto the current task_struct
until after all of the namespaces are created.

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman 2012-07-26 04:02:49 -07:00
parent 142e1d1d5f
commit bcf58e725d
5 changed files with 28 additions and 26 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
include/linux/ipc_namespace.h
View File

@ -133,7 +133,8 @@ static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
#if defined(CONFIG_IPC_NS) #if defined(CONFIG_IPC_NS)
extern struct ipc_namespace *copy_ipcs(unsigned long flags, extern struct ipc_namespace *copy_ipcs(unsigned long flags,
struct task_struct *tsk); struct user_namespace *user_ns, struct ipc_namespace *ns);
static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns) static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
{ {
if (ns) if (ns)
@ -144,12 +145,12 @@ static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)
extern void put_ipc_ns(struct ipc_namespace *ns); extern void put_ipc_ns(struct ipc_namespace *ns);
#else #else
static inline struct ipc_namespace *copy_ipcs(unsigned long flags, static inline struct ipc_namespace *copy_ipcs(unsigned long flags,
struct task_struct *tsk) struct user_namespace *user_ns, struct ipc_namespace *ns)
{ {
if (flags & CLONE_NEWIPC) if (flags & CLONE_NEWIPC)
return ERR_PTR(-EINVAL); return ERR_PTR(-EINVAL);
return tsk->nsproxy->ipc_ns; return ns;
} }
static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns) static inline struct ipc_namespace *get_ipc_ns(struct ipc_namespace *ns)

6
include/linux/utsname.h
View File

@ -33,7 +33,7 @@ static inline void get_uts_ns(struct uts_namespace *ns)
} }
extern struct uts_namespace *copy_utsname(unsigned long flags, extern struct uts_namespace *copy_utsname(unsigned long flags,
struct task_struct *tsk); struct user_namespace *user_ns, struct uts_namespace *old_ns);
extern void free_uts_ns(struct kref *kref); extern void free_uts_ns(struct kref *kref);
static inline void put_uts_ns(struct uts_namespace *ns) static inline void put_uts_ns(struct uts_namespace *ns)
@ -50,12 +50,12 @@ static inline void put_uts_ns(struct uts_namespace *ns)
} }
static inline struct uts_namespace *copy_utsname(unsigned long flags, static inline struct uts_namespace *copy_utsname(unsigned long flags,
struct task_struct *tsk) struct user_namespace *user_ns, struct uts_namespace *old_ns)
{ {
if (flags & CLONE_NEWUTS) if (flags & CLONE_NEWUTS)
return ERR_PTR(-EINVAL); return ERR_PTR(-EINVAL);
return tsk->nsproxy->uts_ns; return old_ns;
} }
#endif #endif

10
ipc/namespace.c
View File

@ -16,7 +16,7 @@
#include "util.h" #include "util.h"
static struct ipc_namespace *create_ipc_ns(struct task_struct *tsk, static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
struct ipc_namespace *old_ns) struct ipc_namespace *old_ns)
{ {
struct ipc_namespace *ns; struct ipc_namespace *ns;
@ -46,19 +46,17 @@ static struct ipc_namespace *create_ipc_ns(struct task_struct *tsk,
ipcns_notify(IPCNS_CREATED); ipcns_notify(IPCNS_CREATED);
register_ipcns_notifier(ns); register_ipcns_notifier(ns);
ns->user_ns = get_user_ns(task_cred_xxx(tsk, user_ns)); ns->user_ns = get_user_ns(user_ns);
return ns; return ns;
} }
struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *copy_ipcs(unsigned long flags,
struct task_struct *tsk) struct user_namespace *user_ns, struct ipc_namespace *ns)
{ {
struct ipc_namespace *ns = tsk->nsproxy->ipc_ns;
if (!(flags & CLONE_NEWIPC)) if (!(flags & CLONE_NEWIPC))
return get_ipc_ns(ns); return get_ipc_ns(ns);
return create_ipc_ns(tsk, ns); return create_ipc_ns(user_ns, ns);
} }
/* /*

22
kernel/nsproxy.c
View File

@ -57,7 +57,8 @@ static inline struct nsproxy *create_nsproxy(void)
* leave it to the caller to do proper locking and attach it to task. * leave it to the caller to do proper locking and attach it to task.
*/ */
static struct nsproxy *create_new_namespaces(unsigned long flags, static struct nsproxy *create_new_namespaces(unsigned long flags,
struct task_struct *tsk, struct fs_struct *new_fs) struct task_struct *tsk, struct user_namespace *user_ns,
struct fs_struct *new_fs)
{ {
struct nsproxy *new_nsp; struct nsproxy *new_nsp;
int err; int err;
@ -66,31 +67,31 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
if (!new_nsp) if (!new_nsp)
return ERR_PTR(-ENOMEM); return ERR_PTR(-ENOMEM);
new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, task_cred_xxx(tsk, user_ns), new_fs); new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, user_ns, new_fs);
if (IS_ERR(new_nsp->mnt_ns)) { if (IS_ERR(new_nsp->mnt_ns)) {
err = PTR_ERR(new_nsp->mnt_ns); err = PTR_ERR(new_nsp->mnt_ns);
goto out_ns; goto out_ns;
} }
new_nsp->uts_ns = copy_utsname(flags, tsk); new_nsp->uts_ns = copy_utsname(flags, user_ns, 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); err = PTR_ERR(new_nsp->uts_ns);
goto out_uts; goto out_uts;
} }
new_nsp->ipc_ns = copy_ipcs(flags, tsk); new_nsp->ipc_ns = copy_ipcs(flags, user_ns, 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); err = PTR_ERR(new_nsp->ipc_ns);
goto out_ipc; goto out_ipc;
} }
new_nsp->pid_ns = copy_pid_ns(flags, task_cred_xxx(tsk, user_ns), tsk->nsproxy->pid_ns); new_nsp->pid_ns = copy_pid_ns(flags, user_ns, 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); err = PTR_ERR(new_nsp->pid_ns);
goto out_pid; goto out_pid;
} }
new_nsp->net_ns = copy_net_ns(flags, task_cred_xxx(tsk, user_ns), tsk->nsproxy->net_ns); new_nsp->net_ns = copy_net_ns(flags, user_ns, tsk->nsproxy->net_ns);
if (IS_ERR(new_nsp->net_ns)) { if (IS_ERR(new_nsp->net_ns)) {
err = PTR_ERR(new_nsp->net_ns); err = PTR_ERR(new_nsp->net_ns);
goto out_net; goto out_net;
@ -152,7 +153,8 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
goto out; goto out;
} }
new_ns = create_new_namespaces(flags, tsk, tsk->fs); new_ns = create_new_namespaces(flags, tsk,
task_cred_xxx(tsk, user_ns), tsk->fs);
if (IS_ERR(new_ns)) { if (IS_ERR(new_ns)) {
err = PTR_ERR(new_ns); err = PTR_ERR(new_ns);
goto out; goto out;
@ -186,6 +188,7 @@ void free_nsproxy(struct nsproxy *ns)
int unshare_nsproxy_namespaces(unsigned long unshare_flags, int unshare_nsproxy_namespaces(unsigned long unshare_flags,
struct nsproxy **new_nsp, struct fs_struct *new_fs) struct nsproxy **new_nsp, struct fs_struct *new_fs)
{ {
struct user_namespace *user_ns;
int err = 0; int err = 0;
if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC | if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
@ -195,7 +198,8 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
if (!nsown_capable(CAP_SYS_ADMIN)) if (!nsown_capable(CAP_SYS_ADMIN))
return -EPERM; return -EPERM;
*new_nsp = create_new_namespaces(unshare_flags, current, user_ns = current_user_ns();
*new_nsp = create_new_namespaces(unshare_flags, current, user_ns,
new_fs ? new_fs : current->fs); new_fs ? new_fs : current->fs);
if (IS_ERR(*new_nsp)) { if (IS_ERR(*new_nsp)) {
err = PTR_ERR(*new_nsp); err = PTR_ERR(*new_nsp);
@ -252,7 +256,7 @@ SYSCALL_DEFINE2(setns, int, fd, int, nstype)
if (nstype && (ops->type != nstype)) if (nstype && (ops->type != nstype))
goto out; goto out;
new_nsproxy = create_new_namespaces(0, tsk, tsk->fs); new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs);
if (IS_ERR(new_nsproxy)) { if (IS_ERR(new_nsproxy)) {
err = PTR_ERR(new_nsproxy); err = PTR_ERR(new_nsproxy);
goto out; goto out;

9
kernel/utsname.c
View File

@ -32,7 +32,7 @@ static struct uts_namespace *create_uts_ns(void)
* @old_ns: namespace to clone * @old_ns: namespace to clone
* Return NULL on error (failure to kmalloc), new ns otherwise * Return NULL on error (failure to kmalloc), new ns otherwise
*/ */
static struct uts_namespace *clone_uts_ns(struct task_struct *tsk, static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns,
struct uts_namespace *old_ns) struct uts_namespace *old_ns)
{ {
struct uts_namespace *ns; struct uts_namespace *ns;
@ -43,7 +43,7 @@ static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
down_read(&uts_sem); down_read(&uts_sem);
memcpy(&ns->name, &old_ns->name, sizeof(ns->name)); memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
ns->user_ns = get_user_ns(task_cred_xxx(tsk, user_ns)); ns->user_ns = get_user_ns(user_ns);
up_read(&uts_sem); up_read(&uts_sem);
return ns; return ns;
} }
@ -55,9 +55,8 @@ static struct uts_namespace *clone_uts_ns(struct task_struct *tsk,
* versa. * versa.
*/ */
struct uts_namespace *copy_utsname(unsigned long flags, struct uts_namespace *copy_utsname(unsigned long flags,
struct task_struct *tsk) struct user_namespace *user_ns, struct uts_namespace *old_ns)
{ {
struct uts_namespace *old_ns = tsk->nsproxy->uts_ns;
struct uts_namespace *new_ns; struct uts_namespace *new_ns;
BUG_ON(!old_ns); BUG_ON(!old_ns);
@ -66,7 +65,7 @@ struct uts_namespace *copy_utsname(unsigned long flags,
if (!(flags & CLONE_NEWUTS)) if (!(flags & CLONE_NEWUTS))
return old_ns; return old_ns;
new_ns = clone_uts_ns(tsk, old_ns); new_ns = clone_uts_ns(user_ns, old_ns);
put_uts_ns(old_ns); put_uts_ns(old_ns);
return new_ns; return new_ns;