Messages in this thread Patch in this message | | | Date | Thu, 3 Apr 2008 21:27:51 -0500 | From | "Serge E. Hallyn" <> | Subject | Re: [PATCH 1/1] user namespaces: add ns to user_struct (v3) |
| |
Quoting Serge E. Hallyn (serue@us.ibm.com): > Hi Dave, > > does the following patch against 2.6.25-rc8 fix the problem > with clone(CLONE_NEWUSER) failing when CONFIG_FAIR_USER_SCHED=y?
The patch I sent didn't zero out the kobject before doing kbobject_init_and_add(), so that a kfree(kobj->name) during the registration causes an occasional oops. The following patch fixes that. Dave, please give it a shot and let me know.
thanks, -serge
From 40176b1cc0c1a9c24e8a0b572dce9ab60a8a99df Mon Sep 17 00:00:00 2001 From: sergeh@us.ibm.com <sergeh@us.ibm.com> Date: Wed, 28 Nov 2007 14:50:54 -0800 Subject: [PATCH 1/1] user namespaces: add ns to user_struct (v4)
Add the user_namespace to user_struct.
Move /sys/kernel/uids/<uid> under /sys/kernel/uids/<user_ns_address/<uid>
Without this patch, FAIR_USER_SCHED breaks user namespaces. The -EEXIST for /sys/kernel/uids/<uid> causes the user namespace creation to fail.
Changelog: apr 3: kzalloc user_ns to avoid kfree oops at kobject_init_and_add apr 2: update to 2.6.25-rc8 feb 4: user hash tables are separate by namespace, so remove ns checks from uid_hash_find().
Signed-off-by: Serge Hallyn <serue@us.ibm.com> --- fs/dquot.c | 2 +- fs/ioprio.c | 2 +- include/linux/sched.h | 3 +- include/linux/types.h | 10 +++++++ include/linux/user_namespace.h | 3 ++ kernel/user.c | 56 +++++++++++++++++++++++++++++++++++++--- kernel/user_namespace.c | 13 ++++++++- security/keys/process_keys.c | 8 +++--- 8 files changed, 84 insertions(+), 13 deletions(-)
diff --git a/fs/dquot.c b/fs/dquot.c index 41b9dbd..7414e5d 100644 --- a/fs/dquot.c +++ b/fs/dquot.c @@ -960,7 +960,7 @@ static void send_warning(const struct dquot *dquot, const char warntype) MINOR(dquot->dq_sb->s_dev)); if (ret) goto attr_err_out; - ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID, current->user->uid); + ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID, current->user->uid.uid); if (ret) goto attr_err_out; genlmsg_end(skb, msg_head); diff --git a/fs/ioprio.c b/fs/ioprio.c index c4a1c3c..139da15 100644 --- a/fs/ioprio.c +++ b/fs/ioprio.c @@ -224,7 +224,7 @@ asmlinkage long sys_ioprio_get(int which, int who) break; do_each_thread(g, p) { - if (p->uid != user->uid) + if (!task_user_equiv(p, user)) continue; tmpio = get_task_ioprio(p); if (tmpio < 0) diff --git a/include/linux/sched.h b/include/linux/sched.h index 6a1e7af..1a25884 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -589,7 +589,7 @@ struct user_struct { /* Hash table maintenance information */ struct hlist_node uidhash_node; - uid_t uid; + struct k_uid_t uid; #ifdef CONFIG_USER_SCHED struct task_group *tg; @@ -1654,6 +1654,7 @@ static inline struct user_struct *get_uid(struct user_struct *u) extern void free_uid(struct user_struct *); extern void switch_uid(struct user_struct *); extern void release_uids(struct user_namespace *ns); +extern int task_user_equiv(struct task_struct *tsk, struct user_struct *u); #include <asm/current.h> diff --git a/include/linux/types.h b/include/linux/types.h index 9dc2346..987e58d 100644 --- a/include/linux/types.h +++ b/include/linux/types.h @@ -37,6 +37,16 @@ typedef __kernel_gid32_t gid_t; typedef __kernel_uid16_t uid16_t; typedef __kernel_gid16_t gid16_t; +struct k_uid_t { + uid_t uid; + struct user_namespace *ns; +}; + +struct k_gid_t { + gid_t gid; + struct user_namespace *ns; +}; + typedef unsigned long uintptr_t; #ifdef CONFIG_UID16 diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h index b5f41d4..f0636d7 100644 --- a/include/linux/user_namespace.h +++ b/include/linux/user_namespace.h @@ -12,10 +12,13 @@ struct user_namespace { struct kref kref; struct hlist_head uidhash_table[UIDHASH_SZ]; + struct kobject kobject; struct user_struct *root_user; }; extern struct user_namespace init_user_ns; +extern int register_user_ns_kobj(struct user_namespace *ns); +extern void unregister_user_ns_kobj(struct user_namespace *ns); #ifdef CONFIG_USER_NS diff --git a/kernel/user.c b/kernel/user.c index 7132022..cd6bb89 100644 --- a/kernel/user.c +++ b/kernel/user.c @@ -53,6 +53,10 @@ struct user_struct root_user = { .files = ATOMIC_INIT(0), .sigpending = ATOMIC_INIT(0), .locked_shm = 0, + .uid = { + .uid = 0, + .ns = &init_user_ns, + }, #ifdef CONFIG_KEYS .uid_keyring = &root_user_keyring, .session_keyring = &root_session_keyring, @@ -75,13 +79,23 @@ static void uid_hash_remove(struct user_struct *up) hlist_del_init(&up->uidhash_node); } -static struct user_struct *uid_hash_find(uid_t uid, struct hlist_head *hashent) +int task_user_equiv(struct task_struct *tsk, struct user_struct *u) +{ + if (tsk->uid != u->uid.uid) + return 0; + if (tsk->nsproxy->user_ns != u->uid.ns) + return 0; + return 1; +} + +static struct user_struct *uid_hash_find(uid_t uid, + struct hlist_head *hashent) { struct user_struct *user; struct hlist_node *h; hlist_for_each_entry(user, h, hashent, uidhash_node) { - if (user->uid == uid) { + if (user->uid.uid == uid) { atomic_inc(&user->__count); return user; } @@ -226,7 +240,8 @@ static int uids_user_create(struct user_struct *up) memset(kobj, 0, sizeof(struct kobject)); kobj->kset = uids_kset; - error = kobject_init_and_add(kobj, &uids_ktype, NULL, "%d", up->uid); + error = kobject_init_and_add(kobj, &uids_ktype, &up->uid.ns->kobject, + "%d", up->uid.uid); if (error) { kobject_put(kobj); goto done; @@ -244,10 +259,16 @@ done: */ int __init uids_sysfs_init(void) { + int error; + uids_kset = kset_create_and_add("uids", NULL, kernel_kobj); if (!uids_kset) return -ENOMEM; + error = register_user_ns_kobj(&init_user_ns); + if (error) + return error; + return uids_user_create(&root_user); } @@ -305,6 +326,30 @@ static inline void free_user(struct user_struct *up, unsigned long flags) schedule_work(&up->work); } +int register_user_ns_kobj(struct user_namespace *ns) +{ + struct kobject *obj = &ns->kobject; + int error; + + obj->kset = uids_kset; + + error = kobject_init_and_add(obj, &uids_ktype, &uids_kset->kobj, + "%lx", (unsigned long)ns); + if (error) + return error; + + kobject_uevent(obj, KOBJ_ADD); + + return 0; +} + +void unregister_user_ns_kobj(struct user_namespace *ns) +{ + struct kobject *obj = &ns->kobject; + kobject_uevent(obj, KOBJ_REMOVE); + kobject_del(obj); +} + #else /* CONFIG_USER_SCHED && CONFIG_SYSFS */ int uids_sysfs_init(void) { return 0; } @@ -326,6 +371,8 @@ static inline void free_user(struct user_struct *up, unsigned long flags) kmem_cache_free(uid_cachep, up); } +int register_user_ns_kobj(struct user_namespace *ns) { return 0; } +void unregister_user_ns_kobj(struct user_namespace *ns) {} #endif /* @@ -379,7 +426,8 @@ struct user_struct * alloc_uid(struct user_namespace *ns, uid_t uid) if (!new) goto out_unlock; - new->uid = uid; + new->uid.uid = uid; + new->uid.ns = ns; atomic_set(&new->__count, 1); atomic_set(&new->processes, 0); atomic_set(&new->files, 0); diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c index 4c90062..0ea3bf6 100644 --- a/kernel/user_namespace.c +++ b/kernel/user_namespace.c @@ -19,12 +19,16 @@ static struct user_namespace *clone_user_ns(struct user_namespace *old_ns) { struct user_namespace *ns; struct user_struct *new_user; - int n; + int n, err; - ns = kmalloc(sizeof(struct user_namespace), GFP_KERNEL); + ns = kzalloc(sizeof(struct user_namespace), GFP_KERNEL); if (!ns) return ERR_PTR(-ENOMEM); + err = register_user_ns_kobj(ns); + if (err) + goto out_free_ns; + kref_init(&ns->kref); for (n = 0; n < UIDHASH_SZ; ++n) @@ -47,6 +51,10 @@ static struct user_namespace *clone_user_ns(struct user_namespace *old_ns) switch_uid(new_user); return ns; + +out_free_ns: + kfree(ns); + return ERR_PTR(err); } struct user_namespace * copy_user_ns(int flags, struct user_namespace *old_ns) @@ -71,5 +79,6 @@ void free_user_ns(struct kref *kref) ns = container_of(kref, struct user_namespace, kref); release_uids(ns); + unregister_user_ns_kobj(ns); kfree(ns); } diff --git a/security/keys/process_keys.c b/security/keys/process_keys.c index c886a2b..0343a52 100644 --- a/security/keys/process_keys.c +++ b/security/keys/process_keys.c @@ -75,9 +75,9 @@ int alloc_uid_keyring(struct user_struct *user, int ret; /* concoct a default session keyring */ - sprintf(buf, "_uid_ses.%u", user->uid); + sprintf(buf, "_uid_ses.%u", user->uid.uid); - session_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, ctx, + session_keyring = keyring_alloc(buf, user->uid.uid, (gid_t) -1, ctx, KEY_ALLOC_IN_QUOTA, NULL); if (IS_ERR(session_keyring)) { ret = PTR_ERR(session_keyring); @@ -86,9 +86,9 @@ int alloc_uid_keyring(struct user_struct *user, /* and a UID specific keyring, pointed to by the default session * keyring */ - sprintf(buf, "_uid.%u", user->uid); + sprintf(buf, "_uid.%u", user->uid.uid); - uid_keyring = keyring_alloc(buf, user->uid, (gid_t) -1, ctx, + uid_keyring = keyring_alloc(buf, user->uid.uid, (gid_t) -1, ctx, KEY_ALLOC_IN_QUOTA, session_keyring); if (IS_ERR(uid_keyring)) { key_put(session_keyring); -- 1.5.3.6
| |