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authorLinus Torvalds <torvalds@linux-foundation.org>2012-12-27 10:42:46 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-27 10:42:46 -0800
commitddf75ae34e61bc8472f8b54281ad29bc87274be1 (patch)
treecd93e82253bc35d1bd97859f7b6353223e0c2f84
parent7fd83b47cebb9e4fafab0ff9a058d2bebf29b8f5 (diff)
parent48c6d1217e3dc743e7d3ad9b9def8d4810d13a85 (diff)
downloadconfigs-ddf75ae34e61bc8472f8b54281ad29bc87274be1.tar.gz
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.c1
-rw-r--r--fs/proc/generic.c13
-rw-r--r--include/linux/pid.h1
-rw-r--r--include/linux/pid_namespace.h4
-rw-r--r--kernel/fork.c8
-rw-r--r--kernel/pid.c15
-rw-r--r--kernel/pid_namespace.c4
7 files changed, 35 insertions, 11 deletions
diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c
index fed74d193ff..e95b94945d5 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 e064f562b1f..76ddae83daa 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 b152d44fb18..2381c973d89 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 bf285999273..215e5e3dda1 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 a31b823b3c2..65ca6d27f24 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 36aa02ff17d..de9af600006 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 fdbd0cdf271..c1c3dc1c602 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;