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-rw-r--r--kernel/cred.c15
-rw-r--r--kernel/fork.c19
-rw-r--r--kernel/nsproxy.c15
-rw-r--r--kernel/sys.c4
-rw-r--r--kernel/user.c47
-rw-r--r--kernel/user_namespace.c75
6 files changed, 76 insertions, 99 deletions
diff --git a/kernel/cred.c b/kernel/cred.c
index 13697ca2bb3..ff7bc071991 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -274,6 +274,7 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags)
struct thread_group_cred *tgcred;
#endif
struct cred *new;
+ int ret;
mutex_init(&p->cred_exec_mutex);
@@ -293,6 +294,12 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags)
if (!new)
return -ENOMEM;
+ if (clone_flags & CLONE_NEWUSER) {
+ ret = create_user_ns(new);
+ if (ret < 0)
+ goto error_put;
+ }
+
#ifdef CONFIG_KEYS
/* new threads get their own thread keyrings if their parent already
* had one */
@@ -309,8 +316,8 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags)
if (!(clone_flags & CLONE_THREAD)) {
tgcred = kmalloc(sizeof(*tgcred), GFP_KERNEL);
if (!tgcred) {
- put_cred(new);
- return -ENOMEM;
+ ret = -ENOMEM;
+ goto error_put;
}
atomic_set(&tgcred->usage, 1);
spin_lock_init(&tgcred->lock);
@@ -325,6 +332,10 @@ int copy_creds(struct task_struct *p, unsigned long clone_flags)
atomic_inc(&new->user->processes);
p->cred = p->real_cred = get_cred(new);
return 0;
+
+error_put:
+ put_cred(new);
+ return ret;
}
/**
diff --git a/kernel/fork.c b/kernel/fork.c
index 29c18c14812..1dd89451fae 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -976,7 +976,7 @@ static struct task_struct *copy_process(unsigned long clone_flags,
if (atomic_read(&p->real_cred->user->processes) >=
p->signal->rlim[RLIMIT_NPROC].rlim_cur) {
if (!capable(CAP_SYS_ADMIN) && !capable(CAP_SYS_RESOURCE) &&
- p->real_cred->user != current->nsproxy->user_ns->root_user)
+ p->real_cred->user != INIT_USER)
goto bad_fork_free;
}
@@ -1335,6 +1335,20 @@ long do_fork(unsigned long clone_flags,
long nr;
/*
+ * Do some preliminary argument and permissions checking before we
+ * actually start allocating stuff
+ */
+ if (clone_flags & CLONE_NEWUSER) {
+ if (clone_flags & CLONE_THREAD)
+ return -EINVAL;
+ /* hopefully this check will go away when userns support is
+ * complete
+ */
+ if (!capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ }
+
+ /*
* We hope to recycle these flags after 2.6.26
*/
if (unlikely(clone_flags & CLONE_STOPPED)) {
@@ -1581,8 +1595,7 @@ asmlinkage long sys_unshare(unsigned long unshare_flags)
err = -EINVAL;
if (unshare_flags & ~(CLONE_THREAD|CLONE_FS|CLONE_NEWNS|CLONE_SIGHAND|
CLONE_VM|CLONE_FILES|CLONE_SYSVSEM|
- CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWUSER|
- CLONE_NEWNET))
+ CLONE_NEWUTS|CLONE_NEWIPC|CLONE_NEWNET))
goto bad_unshare_out;
/*
diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
index 1d3ef29a258..63598dca2d0 100644
--- a/kernel/nsproxy.c
+++ b/kernel/nsproxy.c
@@ -80,12 +80,6 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
goto out_pid;
}
- new_nsp->user_ns = copy_user_ns(flags, tsk->nsproxy->user_ns);
- if (IS_ERR(new_nsp->user_ns)) {
- err = PTR_ERR(new_nsp->user_ns);
- goto out_user;
- }
-
new_nsp->net_ns = copy_net_ns(flags, tsk->nsproxy->net_ns);
if (IS_ERR(new_nsp->net_ns)) {
err = PTR_ERR(new_nsp->net_ns);
@@ -95,9 +89,6 @@ static struct nsproxy *create_new_namespaces(unsigned long flags,
return new_nsp;
out_net:
- if (new_nsp->user_ns)
- put_user_ns(new_nsp->user_ns);
-out_user:
if (new_nsp->pid_ns)
put_pid_ns(new_nsp->pid_ns);
out_pid:
@@ -130,7 +121,7 @@ int copy_namespaces(unsigned long flags, struct task_struct *tsk)
get_nsproxy(old_ns);
if (!(flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWUSER | CLONE_NEWPID | CLONE_NEWNET)))
+ CLONE_NEWPID | CLONE_NEWNET)))
return 0;
if (!capable(CAP_SYS_ADMIN)) {
@@ -173,8 +164,6 @@ void free_nsproxy(struct nsproxy *ns)
put_ipc_ns(ns->ipc_ns);
if (ns->pid_ns)
put_pid_ns(ns->pid_ns);
- if (ns->user_ns)
- put_user_ns(ns->user_ns);
put_net(ns->net_ns);
kmem_cache_free(nsproxy_cachep, ns);
}
@@ -189,7 +178,7 @@ int unshare_nsproxy_namespaces(unsigned long unshare_flags,
int err = 0;
if (!(unshare_flags & (CLONE_NEWNS | CLONE_NEWUTS | CLONE_NEWIPC |
- CLONE_NEWUSER | CLONE_NEWNET)))
+ CLONE_NEWNET)))
return 0;
if (!capable(CAP_SYS_ADMIN))
diff --git a/kernel/sys.c b/kernel/sys.c
index ab735040468..ebe65c2c987 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -565,13 +565,13 @@ static int set_user(struct cred *new)
{
struct user_struct *new_user;
- new_user = alloc_uid(current->nsproxy->user_ns, new->uid);
+ new_user = alloc_uid(current_user_ns(), new->uid);
if (!new_user)
return -EAGAIN;
if (atomic_read(&new_user->processes) >=
current->signal->rlim[RLIMIT_NPROC].rlim_cur &&
- new_user != current->nsproxy->user_ns->root_user) {
+ new_user != INIT_USER) {
free_uid(new_user);
return -EAGAIN;
}
diff --git a/kernel/user.c b/kernel/user.c
index d476307dd4b..c0ef3a46443 100644
--- a/kernel/user.c
+++ b/kernel/user.c
@@ -20,9 +20,9 @@
struct user_namespace init_user_ns = {
.kref = {
- .refcount = ATOMIC_INIT(2),
+ .refcount = ATOMIC_INIT(1),
},
- .root_user = &root_user,
+ .creator = &root_user,
};
EXPORT_SYMBOL_GPL(init_user_ns);
@@ -48,12 +48,14 @@ static struct kmem_cache *uid_cachep;
*/
static DEFINE_SPINLOCK(uidhash_lock);
+/* root_user.__count is 2, 1 for init task cred, 1 for init_user_ns->creator */
struct user_struct root_user = {
- .__count = ATOMIC_INIT(1),
+ .__count = ATOMIC_INIT(2),
.processes = ATOMIC_INIT(1),
.files = ATOMIC_INIT(0),
.sigpending = ATOMIC_INIT(0),
.locked_shm = 0,
+ .user_ns = &init_user_ns,
#ifdef CONFIG_USER_SCHED
.tg = &init_task_group,
#endif
@@ -314,12 +316,13 @@ done:
* IRQ state (as stored in flags) is restored and uidhash_lock released
* upon function exit.
*/
-static inline void free_user(struct user_struct *up, unsigned long flags)
+static void free_user(struct user_struct *up, unsigned long flags)
{
/* restore back the count */
atomic_inc(&up->__count);
spin_unlock_irqrestore(&uidhash_lock, flags);
+ put_user_ns(up->user_ns);
INIT_WORK(&up->work, remove_user_sysfs_dir);
schedule_work(&up->work);
}
@@ -335,13 +338,14 @@ static inline void uids_mutex_unlock(void) { }
* IRQ state (as stored in flags) is restored and uidhash_lock released
* upon function exit.
*/
-static inline void free_user(struct user_struct *up, unsigned long flags)
+static void free_user(struct user_struct *up, unsigned long flags)
{
uid_hash_remove(up);
spin_unlock_irqrestore(&uidhash_lock, flags);
sched_destroy_user(up);
key_put(up->uid_keyring);
key_put(up->session_keyring);
+ put_user_ns(up->user_ns);
kmem_cache_free(uid_cachep, up);
}
@@ -357,7 +361,7 @@ struct user_struct *find_user(uid_t uid)
{
struct user_struct *ret;
unsigned long flags;
- struct user_namespace *ns = current->nsproxy->user_ns;
+ struct user_namespace *ns = current_user()->user_ns;
spin_lock_irqsave(&uidhash_lock, flags);
ret = uid_hash_find(uid, uidhashentry(ns, uid));
@@ -404,6 +408,8 @@ struct user_struct *alloc_uid(struct user_namespace *ns, uid_t uid)
if (sched_create_user(new) < 0)
goto out_free_user;
+ new->user_ns = get_user_ns(ns);
+
if (uids_user_create(new))
goto out_destoy_sched;
@@ -427,7 +433,6 @@ struct user_struct *alloc_uid(struct user_namespace *ns, uid_t uid)
up = new;
}
spin_unlock_irq(&uidhash_lock);
-
}
uids_mutex_unlock();
@@ -436,6 +441,7 @@ struct user_struct *alloc_uid(struct user_namespace *ns, uid_t uid)
out_destoy_sched:
sched_destroy_user(new);
+ put_user_ns(new->user_ns);
out_free_user:
kmem_cache_free(uid_cachep, new);
out_unlock:
@@ -443,33 +449,6 @@ out_unlock:
return NULL;
}
-#ifdef CONFIG_USER_NS
-void release_uids(struct user_namespace *ns)
-{
- int i;
- unsigned long flags;
- struct hlist_head *head;
- struct hlist_node *nd;
-
- spin_lock_irqsave(&uidhash_lock, flags);
- /*
- * collapse the chains so that the user_struct-s will
- * be still alive, but not in hashes. subsequent free_uid()
- * will free them.
- */
- for (i = 0; i < UIDHASH_SZ; i++) {
- head = ns->uidhash_table + i;
- while (!hlist_empty(head)) {
- nd = head->first;
- hlist_del_init(nd);
- }
- }
- spin_unlock_irqrestore(&uidhash_lock, flags);
-
- free_uid(ns->root_user);
-}
-#endif
-
static int __init uid_cache_init(void)
{
int n;
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 0d9c51d6733..79084311ee5 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -9,70 +9,55 @@
#include <linux/nsproxy.h>
#include <linux/slab.h>
#include <linux/user_namespace.h>
+#include <linux/cred.h>
/*
- * Clone a new ns copying an original user ns, setting refcount to 1
- * @old_ns: namespace to clone
- * Return NULL on error (failure to kmalloc), new ns otherwise
+ * Create a new user namespace, deriving the creator from the user in the
+ * passed credentials, and replacing that user with the new root user for the
+ * new namespace.
+ *
+ * This is called by copy_creds(), which will finish setting the target task's
+ * credentials.
*/
-static struct user_namespace *clone_user_ns(struct user_namespace *old_ns)
+int create_user_ns(struct cred *new)
{
struct user_namespace *ns;
- struct user_struct *new_user;
- struct cred *new;
+ struct user_struct *root_user;
int n;
ns = kmalloc(sizeof(struct user_namespace), GFP_KERNEL);
if (!ns)
- return ERR_PTR(-ENOMEM);
+ return -ENOMEM;
kref_init(&ns->kref);
for (n = 0; n < UIDHASH_SZ; ++n)
INIT_HLIST_HEAD(ns->uidhash_table + n);
- /* Insert new root user. */
- ns->root_user = alloc_uid(ns, 0);
- if (!ns->root_user) {
+ /* Alloc new root user. */
+ root_user = alloc_uid(ns, 0);
+ if (!root_user) {
kfree(ns);
- return ERR_PTR(-ENOMEM);
+ return -ENOMEM;
}
- /* Reset current->user with a new one */
- new_user = alloc_uid(ns, current_uid());
- if (!new_user) {
- free_uid(ns->root_user);
- kfree(ns);
- return ERR_PTR(-ENOMEM);
- }
-
- /* Install the new user */
- new = prepare_creds();
- if (!new) {
- free_uid(new_user);
- free_uid(ns->root_user);
- kfree(ns);
- }
- free_uid(new->user);
- new->user = new_user;
- commit_creds(new);
- return ns;
-}
-
-struct user_namespace * copy_user_ns(int flags, struct user_namespace *old_ns)
-{
- struct user_namespace *new_ns;
-
- BUG_ON(!old_ns);
- get_user_ns(old_ns);
-
- if (!(flags & CLONE_NEWUSER))
- return old_ns;
+ /* set the new root user in the credentials under preparation */
+ ns->creator = new->user;
+ new->user = root_user;
+ new->uid = new->euid = new->suid = new->fsuid = 0;
+ new->gid = new->egid = new->sgid = new->fsgid = 0;
+ put_group_info(new->group_info);
+ new->group_info = get_group_info(&init_groups);
+#ifdef CONFIG_KEYS
+ key_put(new->request_key_auth);
+ new->request_key_auth = NULL;
+#endif
+ /* tgcred will be cleared in our caller bc CLONE_THREAD won't be set */
- new_ns = clone_user_ns(old_ns);
+ /* alloc_uid() incremented the userns refcount. Just set it to 1 */
+ kref_set(&ns->kref, 1);
- put_user_ns(old_ns);
- return new_ns;
+ return 0;
}
void free_user_ns(struct kref *kref)
@@ -80,7 +65,7 @@ void free_user_ns(struct kref *kref)
struct user_namespace *ns;
ns = container_of(kref, struct user_namespace, kref);
- release_uids(ns);
+ free_uid(ns->creator);
kfree(ns);
}
EXPORT_SYMBOL(free_user_ns);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-18 11:21:13 +0000