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author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-27 10:42:46 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-27 10:42:46 -0800 |
commit | ddf75ae34e61bc8472f8b54281ad29bc87274be1 (patch) | |
tree | cd93e82253bc35d1bd97859f7b6353223e0c2f84 | |
parent | 7fd83b47cebb9e4fafab0ff9a058d2bebf29b8f5 (diff) | |
parent | 48c6d1217e3dc743e7d3ad9b9def8d4810d13a85 (diff) | |
download | lwn-ddf75ae34e61bc8472f8b54281ad29bc87274be1.tar.gz lwn-ddf75ae34e61bc8472f8b54281ad29bc87274be1.zip |
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace
Pull namespace fixes from Eric Biederman:
"This tree includes two bug fixes for problems Oleg spotted on his
review of the recent pid namespace work. A small fix to not enable
bottom halves with irqs disabled, and a trivial build fix for f2fs
with user namespaces enabled."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
f2fs: Don't assign e_id in f2fs_acl_from_disk
proc: Allow proc_free_inum to be called from any context
pidns: Stop pid allocation when init dies
pidns: Outlaw thread creation after unshare(CLONE_NEWPID)
-rw-r--r-- | fs/f2fs/acl.c | 1 | ||||
-rw-r--r-- | fs/proc/generic.c | 13 | ||||
-rw-r--r-- | include/linux/pid.h | 1 | ||||
-rw-r--r-- | include/linux/pid_namespace.h | 4 | ||||
-rw-r--r-- | kernel/fork.c | 8 | ||||
-rw-r--r-- | kernel/pid.c | 15 | ||||
-rw-r--r-- | kernel/pid_namespace.c | 4 |
7 files changed, 35 insertions, 11 deletions
diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c index fed74d193ffb..e95b94945d5f 100644 --- a/fs/f2fs/acl.c +++ b/fs/f2fs/acl.c @@ -82,7 +82,6 @@ static struct posix_acl *f2fs_acl_from_disk(const char *value, size_t size) case ACL_GROUP_OBJ: case ACL_MASK: case ACL_OTHER: - acl->a_entries[i].e_id = ACL_UNDEFINED_ID; entry = (struct f2fs_acl_entry *)((char *)entry + sizeof(struct f2fs_acl_entry_short)); break; diff --git a/fs/proc/generic.c b/fs/proc/generic.c index e064f562b1f7..76ddae83daa5 100644 --- a/fs/proc/generic.c +++ b/fs/proc/generic.c @@ -352,18 +352,18 @@ retry: if (!ida_pre_get(&proc_inum_ida, GFP_KERNEL)) return -ENOMEM; - spin_lock_bh(&proc_inum_lock); + spin_lock_irq(&proc_inum_lock); error = ida_get_new(&proc_inum_ida, &i); - spin_unlock_bh(&proc_inum_lock); + spin_unlock_irq(&proc_inum_lock); if (error == -EAGAIN) goto retry; else if (error) return error; if (i > UINT_MAX - PROC_DYNAMIC_FIRST) { - spin_lock_bh(&proc_inum_lock); + spin_lock_irq(&proc_inum_lock); ida_remove(&proc_inum_ida, i); - spin_unlock_bh(&proc_inum_lock); + spin_unlock_irq(&proc_inum_lock); return -ENOSPC; } *inum = PROC_DYNAMIC_FIRST + i; @@ -372,9 +372,10 @@ retry: void proc_free_inum(unsigned int inum) { - spin_lock_bh(&proc_inum_lock); + unsigned long flags; + spin_lock_irqsave(&proc_inum_lock, flags); ida_remove(&proc_inum_ida, inum - PROC_DYNAMIC_FIRST); - spin_unlock_bh(&proc_inum_lock); + spin_unlock_irqrestore(&proc_inum_lock, flags); } static void *proc_follow_link(struct dentry *dentry, struct nameidata *nd) diff --git a/include/linux/pid.h b/include/linux/pid.h index b152d44fb181..2381c973d897 100644 --- a/include/linux/pid.h +++ b/include/linux/pid.h @@ -121,6 +121,7 @@ int next_pidmap(struct pid_namespace *pid_ns, unsigned int last); extern struct pid *alloc_pid(struct pid_namespace *ns); extern void free_pid(struct pid *pid); +extern void disable_pid_allocation(struct pid_namespace *ns); /* * ns_of_pid() returns the pid namespace in which the specified pid was diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h index bf285999273a..215e5e3dda10 100644 --- a/include/linux/pid_namespace.h +++ b/include/linux/pid_namespace.h @@ -21,7 +21,7 @@ struct pid_namespace { struct kref kref; struct pidmap pidmap[PIDMAP_ENTRIES]; int last_pid; - int nr_hashed; + unsigned int nr_hashed; struct task_struct *child_reaper; struct kmem_cache *pid_cachep; unsigned int level; @@ -42,6 +42,8 @@ struct pid_namespace { extern struct pid_namespace init_pid_ns; +#define PIDNS_HASH_ADDING (1U << 31) + #ifdef CONFIG_PID_NS static inline struct pid_namespace *get_pid_ns(struct pid_namespace *ns) { diff --git a/kernel/fork.c b/kernel/fork.c index a31b823b3c2d..65ca6d27f24e 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1166,6 +1166,14 @@ static struct task_struct *copy_process(unsigned long clone_flags, current->signal->flags & SIGNAL_UNKILLABLE) return ERR_PTR(-EINVAL); + /* + * If the new process will be in a different pid namespace + * don't allow the creation of threads. + */ + if ((clone_flags & (CLONE_VM|CLONE_NEWPID)) && + (task_active_pid_ns(current) != current->nsproxy->pid_ns)) + return ERR_PTR(-EINVAL); + retval = security_task_create(clone_flags); if (retval) goto fork_out; diff --git a/kernel/pid.c b/kernel/pid.c index 36aa02ff17d6..de9af600006f 100644 --- a/kernel/pid.c +++ b/kernel/pid.c @@ -270,7 +270,6 @@ void free_pid(struct pid *pid) wake_up_process(ns->child_reaper); break; case 0: - ns->nr_hashed = -1; schedule_work(&ns->proc_work); break; } @@ -319,7 +318,7 @@ struct pid *alloc_pid(struct pid_namespace *ns) upid = pid->numbers + ns->level; spin_lock_irq(&pidmap_lock); - if (ns->nr_hashed < 0) + if (!(ns->nr_hashed & PIDNS_HASH_ADDING)) goto out_unlock; for ( ; upid >= pid->numbers; --upid) { hlist_add_head_rcu(&upid->pid_chain, @@ -342,6 +341,13 @@ out_free: goto out; } +void disable_pid_allocation(struct pid_namespace *ns) +{ + spin_lock_irq(&pidmap_lock); + ns->nr_hashed &= ~PIDNS_HASH_ADDING; + spin_unlock_irq(&pidmap_lock); +} + struct pid *find_pid_ns(int nr, struct pid_namespace *ns) { struct hlist_node *elem; @@ -573,6 +579,9 @@ void __init pidhash_init(void) void __init pidmap_init(void) { + /* Veryify no one has done anything silly */ + BUILD_BUG_ON(PID_MAX_LIMIT >= PIDNS_HASH_ADDING); + /* bump default and minimum pid_max based on number of cpus */ pid_max = min(pid_max_max, max_t(int, pid_max, PIDS_PER_CPU_DEFAULT * num_possible_cpus())); @@ -584,7 +593,7 @@ void __init pidmap_init(void) /* Reserve PID 0. We never call free_pidmap(0) */ set_bit(0, init_pid_ns.pidmap[0].page); atomic_dec(&init_pid_ns.pidmap[0].nr_free); - init_pid_ns.nr_hashed = 1; + init_pid_ns.nr_hashed = PIDNS_HASH_ADDING; init_pid_ns.pid_cachep = KMEM_CACHE(pid, SLAB_HWCACHE_ALIGN | SLAB_PANIC); diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index fdbd0cdf271a..c1c3dc1c6023 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -115,6 +115,7 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns ns->level = level; ns->parent = get_pid_ns(parent_pid_ns); ns->user_ns = get_user_ns(user_ns); + ns->nr_hashed = PIDNS_HASH_ADDING; INIT_WORK(&ns->proc_work, proc_cleanup_work); set_bit(0, ns->pidmap[0].page); @@ -181,6 +182,9 @@ void zap_pid_ns_processes(struct pid_namespace *pid_ns) int rc; struct task_struct *task, *me = current; + /* Don't allow any more processes into the pid namespace */ + disable_pid_allocation(pid_ns); + /* Ignore SIGCHLD causing any terminated children to autoreap */ spin_lock_irq(&me->sighand->siglock); me->sighand->action[SIGCHLD - 1].sa.sa_handler = SIG_IGN; |