4 files changed, 49 insertions, 25 deletions

diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
index 826de7a12a20..9b676ead35c3 100644
--- a/include/linux/user_namespace.h
+++ b/include/linux/user_namespace.h
@@ -23,6 +23,12 @@ struct uid_gid_map {	/* 64 bytes -- 1 cache line */
 #define USERNS_INIT_FLAGS USERNS_SETGROUPS_ALLOWED
 
 struct ucounts;
+
+enum ucount_type {
+        UCOUNT_USER_NAMESPACES,
+        UCOUNT_COUNTS,
+};
+
 struct user_namespace {
         struct uid_gid_map      uid_map;
         struct uid_gid_map      gid_map;
@@ -46,7 +52,7 @@ struct user_namespace {
         struct ctl_table_header *sysctls;
 #endif
         struct ucounts          *ucounts;
-        int max_user_namespaces;
+        int ucount_max[UCOUNT_COUNTS];
 };
 
 struct ucounts {
@@ -54,15 +60,15 @@ struct ucounts {
         struct user_namespace *ns;
         kuid_t uid;
         atomic_t count;
-        atomic_t user_namespaces;
+        atomic_t ucount[UCOUNT_COUNTS];
 };
 
 extern struct user_namespace init_user_ns;
 
 bool setup_userns_sysctls(struct user_namespace *ns);
 void retire_userns_sysctls(struct user_namespace *ns);
-struct ucounts *inc_user_namespaces(struct user_namespace *ns, kuid_t uid);
-void dec_user_namespaces(struct ucounts *ucounts);
+struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid, enum ucount_type type);
+void dec_ucount(struct ucounts *ucounts, enum ucount_type type);
 
 #ifdef CONFIG_USER_NS
 
diff --git a/kernel/fork.c b/kernel/fork.c
index d8cde533ace3..3cb4853a59aa 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -302,6 +302,7 @@ int arch_task_struct_size __read_mostly;
 
 void __init fork_init(void)
 {
+        int i;
 #ifndef CONFIG_ARCH_TASK_STRUCT_ALLOCATOR
 #ifndef ARCH_MIN_TASKALIGN
 #define ARCH_MIN_TASKALIGN      L1_CACHE_BYTES
@@ -322,7 +323,9 @@ void __init fork_init(void)
         init_task.signal->rlim[RLIMIT_SIGPENDING] =
                 init_task.signal->rlim[RLIMIT_NPROC];
 
-        init_user_ns.max_user_namespaces = max_threads/2;
+        for (i = 0; i < UCOUNT_COUNTS; i++) {
+                init_user_ns.ucount_max[i] = max_threads/2;
+        }
 }
 
 int __weak arch_dup_task_struct(struct task_struct *dst,
diff --git a/kernel/ucount.c b/kernel/ucount.c
index 33c418718304..0f9ab3b26185 100644
--- a/kernel/ucount.c
+++ b/kernel/ucount.c
@@ -57,16 +57,17 @@ static struct ctl_table_root set_root = {
 
 static int zero = 0;
 static int int_max = INT_MAX;
+#define UCOUNT_ENTRY(name)                              \
+        {                                               \
+                .procname       = name,                 \
+                .maxlen         = sizeof(int),          \
+                .mode           = 0644,                 \
+                .proc_handler   = proc_dointvec_minmax, \
+                .extra1         = &zero,                \
+                .extra2         = &int_max,             \
+        }
 static struct ctl_table user_table[] = {
-        {
-                .procname       = "max_user_namespaces",
-                .data           = &init_user_ns.max_user_namespaces,
-                .maxlen         = sizeof(init_user_ns.max_user_namespaces),
-                .mode           = 0644,
-                .proc_handler   = proc_dointvec_minmax,
-                .extra1         = &zero,
-                .extra2         = &int_max,
-        },
+        UCOUNT_ENTRY("max_user_namespaces"),
         { }
 };
 #endif /* CONFIG_SYSCTL */
@@ -78,8 +79,10 @@ bool setup_userns_sysctls(struct user_namespace *ns)
         setup_sysctl_set(&ns->set, &set_root, set_is_seen);
         tbl = kmemdup(user_table, sizeof(user_table), GFP_KERNEL);
         if (tbl) {
-                tbl[0].data = &ns->max_user_namespaces;
-
+                int i;
+                for (i = 0; i < UCOUNT_COUNTS; i++) {
+                        tbl[i].data = &ns->ucount_max[i];
+                }
                 ns->sysctls = __register_sysctl_table(&ns->set, "user", tbl);
         }
         if (!ns->sysctls) {
@@ -172,7 +175,8 @@ static inline bool atomic_inc_below(atomic_t *v, int u)
         }
 }
 
-struct ucounts *inc_user_namespaces(struct user_namespace *ns, kuid_t uid)
+struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid,
+                           enum ucount_type type)
 {
         struct ucounts *ucounts, *iter, *bad;
         struct user_namespace *tns;
@@ -180,31 +184,30 @@ struct ucounts *inc_user_namespaces(struct user_namespace *ns, kuid_t uid)
         for (iter = ucounts; iter; iter = tns->ucounts) {
                 int max;
                 tns = iter->ns;
-                max = READ_ONCE(tns->max_user_namespaces);
-                if (!atomic_inc_below(&iter->user_namespaces, max))
+                max = READ_ONCE(tns->ucount_max[type]);
+                if (!atomic_inc_below(&iter->ucount[type], max))
                         goto fail;
         }
         return ucounts;
 fail:
         bad = iter;
         for (iter = ucounts; iter != bad; iter = iter->ns->ucounts)
-                atomic_dec(&iter->user_namespaces);
+                atomic_dec(&iter->ucount[type]);
 
         put_ucounts(ucounts);
         return NULL;
 }
 
-void dec_user_namespaces(struct ucounts *ucounts)
+void dec_ucount(struct ucounts *ucounts, enum ucount_type type)
 {
         struct ucounts *iter;
         for (iter = ucounts; iter; iter = iter->ns->ucounts) {
-                int dec = atomic_dec_if_positive(&iter->user_namespaces);
+                int dec = atomic_dec_if_positive(&iter->ucount[type]);
                 WARN_ON_ONCE(dec < 0);
         }
         put_ucounts(ucounts);
 }
 
-
 static __init int user_namespace_sysctl_init(void)
 {
 #ifdef CONFIG_SYSCTL
diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
index 58c67e5f851c..0edafe305861 100644
--- a/kernel/user_namespace.c
+++ b/kernel/user_namespace.c
@@ -31,6 +31,16 @@ static bool new_idmap_permitted(const struct file *file,
                                 struct uid_gid_map *map);
 static void free_user_ns(struct work_struct *work);
 
+static struct ucounts *inc_user_namespaces(struct user_namespace *ns, kuid_t uid)
+{
+        return inc_ucount(ns, uid, UCOUNT_USER_NAMESPACES);
+}
+
+static void dec_user_namespaces(struct ucounts *ucounts)
+{
+        return dec_ucount(ucounts, UCOUNT_USER_NAMESPACES);
+}
+
 static void set_cred_user_ns(struct cred *cred, struct user_namespace *user_ns)
 {
         /* Start with the same capabilities as init but useless for doing
@@ -64,7 +74,7 @@ int create_user_ns(struct cred *new)
         kuid_t owner = new->euid;
         kgid_t group = new->egid;
         struct ucounts *ucounts;
-        int ret;
+        int ret, i;
 
         ret = -EUSERS;
         if (parent_ns->level > 32)
@@ -110,7 +120,9 @@ int create_user_ns(struct cred *new)
         ns->owner = owner;
         ns->group = group;
         INIT_WORK(&ns->work, free_user_ns);
-        ns->max_user_namespaces = INT_MAX;
+        for (i = 0; i < UCOUNT_COUNTS; i++) {
+                ns->ucount_max[i] = INT_MAX;
+        }
         ns->ucounts = ucounts;
 
         /* Inherit USERNS_SETGROUPS_ALLOWED from our parent */