diff options
| author | Eric W. Biederman <ebiederm@xmission.com> | 2016-08-08 21:08:36 +0200 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2016-08-08 21:42:01 +0200 |
| commit | f333c700c6100b53050980986be922bb21466e29 (patch) | |
| tree | 60554e8ad7eeda0cac508cade356a1358171df22 /kernel | |
| parent | userns: Generalize the user namespace count into ucount (diff) | |
| download | linux-f333c700c6100b53050980986be922bb21466e29.tar.xz linux-f333c700c6100b53050980986be922bb21466e29.zip | |
pidns: Add a limit on the number of pid namespaces
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/pid_namespace.c | 25 | ||||
| -rw-r--r-- | kernel/ucount.c | 1 |
2 files changed, 22 insertions, 4 deletions
diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c index a65ba137fd15..30a7f3351932 100644 --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -79,23 +79,36 @@ static void proc_cleanup_work(struct work_struct *work) /* MAX_PID_NS_LEVEL is needed for limiting size of 'struct pid' */ #define MAX_PID_NS_LEVEL 32 +static struct ucounts *inc_pid_namespaces(struct user_namespace *ns) +{ + return inc_ucount(ns, current_euid(), UCOUNT_PID_NAMESPACES); +} + +static void dec_pid_namespaces(struct ucounts *ucounts) +{ + dec_ucount(ucounts, UCOUNT_PID_NAMESPACES); +} + static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns, struct pid_namespace *parent_pid_ns) { struct pid_namespace *ns; unsigned int level = parent_pid_ns->level + 1; + struct ucounts *ucounts; int i; int err; - if (level > MAX_PID_NS_LEVEL) { - err = -EINVAL; + err = -EINVAL; + if (level > MAX_PID_NS_LEVEL) + goto out; + ucounts = inc_pid_namespaces(user_ns); + if (!ucounts) goto out; - } err = -ENOMEM; ns = kmem_cache_zalloc(pid_ns_cachep, GFP_KERNEL); if (ns == NULL) - goto out; + goto out_dec; ns->pidmap[0].page = kzalloc(PAGE_SIZE, GFP_KERNEL); if (!ns->pidmap[0].page) @@ -114,6 +127,7 @@ 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->ucounts = ucounts; ns->nr_hashed = PIDNS_HASH_ADDING; INIT_WORK(&ns->proc_work, proc_cleanup_work); @@ -129,6 +143,8 @@ out_free_map: kfree(ns->pidmap[0].page); out_free: kmem_cache_free(pid_ns_cachep, ns); +out_dec: + dec_pid_namespaces(ucounts); out: return ERR_PTR(err); } @@ -146,6 +162,7 @@ static void destroy_pid_namespace(struct pid_namespace *ns) ns_free_inum(&ns->ns); for (i = 0; i < PIDMAP_ENTRIES; i++) kfree(ns->pidmap[i].page); + dec_pid_namespaces(ns->ucounts); put_user_ns(ns->user_ns); call_rcu(&ns->rcu, delayed_free_pidns); } diff --git a/kernel/ucount.c b/kernel/ucount.c index 0f9ab3b26185..66eca94e4ada 100644 --- a/kernel/ucount.c +++ b/kernel/ucount.c @@ -68,6 +68,7 @@ static int int_max = INT_MAX; } static struct ctl_table user_table[] = { UCOUNT_ENTRY("max_user_namespaces"), + UCOUNT_ENTRY("max_pid_namespaces"), { } }; #endif /* CONFIG_SYSCTL */ |