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authorSerge E. Hallyn <serge@hallyn.com>2011-03-24 02:43:18 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2011-03-24 05:47:03 +0300
commitbb96a6f50be27390dc959ff67d9ea0ea0cfbe177 (patch)
tree478253434235baeb1e4760a25c0a0f01293fbb8a
parent3486740a4f32a6a466f5ac931654d154790ba648 (diff)
downloadlinux-bb96a6f50be27390dc959ff67d9ea0ea0cfbe177.tar.xz
userns: allow sethostname in a container
Changelog: Feb 23: let clone_uts_ns() handle setting uts->user_ns To do so we need to pass in the task_struct who'll get the utsname, so we can get its user_ns. Feb 23: As per Oleg's coment, just pass in tsk, instead of two of its members. Signed-off-by: Serge E. Hallyn <serge.hallyn@canonical.com> Acked-by: "Eric W. Biederman" <ebiederm@xmission.com> Acked-by: Daniel Lezcano <daniel.lezcano@free.fr> Acked-by: David Howells <dhowells@redhat.com> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/utsname.h6
-rw-r--r--kernel/nsproxy.c7
-rw-r--r--kernel/sys.c2
-rw-r--r--kernel/utsname.c12
4 files changed, 12 insertions, 15 deletions
diff --git a/include/linux/utsname.h b/include/linux/utsname.h
index 2c3c0f543705..4e5b0213fdc1 100644
--- a/include/linux/utsname.h
+++ b/include/linux/utsname.h
@@ -54,7 +54,7 @@ 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)
@@ -71,12 +71,12 @@ 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 034dc2ed13ac..b97fc9d04ddf 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/sys.c b/kernel/sys.c
index 1ad48b3b9068..5761c53e19e3 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1181,7 +1181,7 @@ SYSCALL_DEFINE2(sethostname, char __user *, name, int, len)
int errno;
char tmp[__NEW_UTS_LEN];
- if (!capable(CAP_SYS_ADMIN))
+ if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN))
return -EPERM;
if (len < 0 || len > __NEW_UTS_LEN)
return -EINVAL;
diff --git a/kernel/utsname.c b/kernel/utsname.c
index a7b3a8d1ad24..44646179eaba 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;