#include <linux/kmemleak.h>
#include <linux/user_namespace.h>
+struct ucounts init_ucounts = {
+ .ns = &init_user_ns,
+ .uid = GLOBAL_ROOT_UID,
+ .count = ATOMIC_INIT(1),
+};
+
#define UCOUNTS_HASHTABLE_BITS 10
static struct hlist_head ucounts_hashtable[(1 << UCOUNTS_HASHTABLE_BITS)];
static DEFINE_SPINLOCK(ucounts_lock);
.permissions = set_permissions,
};
-#define UCOUNT_ENTRY(name) \
- { \
- .procname = name, \
- .maxlen = sizeof(int), \
- .mode = 0644, \
- .proc_handler = proc_dointvec_minmax, \
- .extra1 = SYSCTL_ZERO, \
- .extra2 = SYSCTL_INT_MAX, \
+static long ue_zero = 0;
+static long ue_int_max = INT_MAX;
+
+#define UCOUNT_ENTRY(name) \
+ { \
+ .procname = name, \
+ .maxlen = sizeof(long), \
+ .mode = 0644, \
+ .proc_handler = proc_doulongvec_minmax, \
+ .extra1 = &ue_zero, \
+ .extra2 = &ue_int_max, \
}
static struct ctl_table user_table[] = {
UCOUNT_ENTRY("max_user_namespaces"),
UCOUNT_ENTRY("max_fanotify_groups"),
UCOUNT_ENTRY("max_fanotify_marks"),
#endif
+ { },
+ { },
+ { },
+ { },
{ }
};
#endif /* CONFIG_SYSCTL */
return NULL;
}
-static struct ucounts *get_ucounts(struct user_namespace *ns, kuid_t uid)
+static void hlist_add_ucounts(struct ucounts *ucounts)
+{
+ struct hlist_head *hashent = ucounts_hashentry(ucounts->ns, ucounts->uid);
+ spin_lock_irq(&ucounts_lock);
+ hlist_add_head(&ucounts->node, hashent);
+ spin_unlock_irq(&ucounts_lock);
+}
+
+struct ucounts *get_ucounts(struct ucounts *ucounts)
+{
+ if (ucounts && atomic_add_negative(1, &ucounts->count)) {
+ put_ucounts(ucounts);
+ ucounts = NULL;
+ }
+ return ucounts;
+}
+
+struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid)
{
struct hlist_head *hashent = ucounts_hashentry(ns, uid);
struct ucounts *ucounts, *new;
+ long overflow;
spin_lock_irq(&ucounts_lock);
ucounts = find_ucounts(ns, uid, hashent);
new->ns = ns;
new->uid = uid;
- new->count = 0;
+ atomic_set(&new->count, 1);
spin_lock_irq(&ucounts_lock);
ucounts = find_ucounts(ns, uid, hashent);
kfree(new);
} else {
hlist_add_head(&new->node, hashent);
- ucounts = new;
+ spin_unlock_irq(&ucounts_lock);
+ return new;
}
}
- if (ucounts->count == INT_MAX)
- ucounts = NULL;
- else
- ucounts->count += 1;
+ overflow = atomic_add_negative(1, &ucounts->count);
spin_unlock_irq(&ucounts_lock);
+ if (overflow) {
+ put_ucounts(ucounts);
+ return NULL;
+ }
return ucounts;
}
-static void put_ucounts(struct ucounts *ucounts)
+void put_ucounts(struct ucounts *ucounts)
{
unsigned long flags;
- spin_lock_irqsave(&ucounts_lock, flags);
- ucounts->count -= 1;
- if (!ucounts->count)
+ if (atomic_dec_and_lock_irqsave(&ucounts->count, &ucounts_lock, flags)) {
hlist_del_init(&ucounts->node);
- else
- ucounts = NULL;
- spin_unlock_irqrestore(&ucounts_lock, flags);
-
- kfree(ucounts);
+ spin_unlock_irqrestore(&ucounts_lock, flags);
+ kfree(ucounts);
+ }
}
-static inline bool atomic_inc_below(atomic_t *v, int u)
+static inline bool atomic_long_inc_below(atomic_long_t *v, int u)
{
- int c, old;
- c = atomic_read(v);
+ long c, old;
+ c = atomic_long_read(v);
for (;;) {
if (unlikely(c >= u))
return false;
- old = atomic_cmpxchg(v, c, c+1);
+ old = atomic_long_cmpxchg(v, c, c+1);
if (likely(old == c))
return true;
c = old;
{
struct ucounts *ucounts, *iter, *bad;
struct user_namespace *tns;
- ucounts = get_ucounts(ns, uid);
+ ucounts = alloc_ucounts(ns, uid);
for (iter = ucounts; iter; iter = tns->ucounts) {
- int max;
+ long max;
tns = iter->ns;
max = READ_ONCE(tns->ucount_max[type]);
- if (!atomic_inc_below(&iter->ucount[type], max))
+ if (!atomic_long_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->ucount[type]);
+ atomic_long_dec(&iter->ucount[type]);
put_ucounts(ucounts);
return NULL;
{
struct ucounts *iter;
for (iter = ucounts; iter; iter = iter->ns->ucounts) {
- int dec = atomic_dec_if_positive(&iter->ucount[type]);
+ long dec = atomic_long_dec_if_positive(&iter->ucount[type]);
WARN_ON_ONCE(dec < 0);
}
put_ucounts(ucounts);
}
+long inc_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v)
+{
+ struct ucounts *iter;
+ long ret = 0;
+
+ for (iter = ucounts; iter; iter = iter->ns->ucounts) {
+ long max = READ_ONCE(iter->ns->ucount_max[type]);
+ long new = atomic_long_add_return(v, &iter->ucount[type]);
+ if (new < 0 || new > max)
+ ret = LONG_MAX;
+ else if (iter == ucounts)
+ ret = new;
+ }
+ return ret;
+}
+
+bool dec_rlimit_ucounts(struct ucounts *ucounts, enum ucount_type type, long v)
+{
+ struct ucounts *iter;
+ long new = -1; /* Silence compiler warning */
+ for (iter = ucounts; iter; iter = iter->ns->ucounts) {
+ long dec = atomic_long_add_return(-v, &iter->ucount[type]);
+ WARN_ON_ONCE(dec < 0);
+ if (iter == ucounts)
+ new = dec;
+ }
+ return (new == 0);
+}
+
+bool is_ucounts_overlimit(struct ucounts *ucounts, enum ucount_type type, unsigned long max)
+{
+ struct ucounts *iter;
+ if (get_ucounts_value(ucounts, type) > max)
+ return true;
+ for (iter = ucounts; iter; iter = iter->ns->ucounts) {
+ max = READ_ONCE(iter->ns->ucount_max[type]);
+ if (get_ucounts_value(iter, type) > max)
+ return true;
+ }
+ return false;
+}
+
static __init int user_namespace_sysctl_init(void)
{
#ifdef CONFIG_SYSCTL
BUG_ON(!user_header);
BUG_ON(!setup_userns_sysctls(&init_user_ns));
#endif
+ hlist_add_ucounts(&init_ucounts);
+ inc_rlimit_ucounts(&init_ucounts, UCOUNT_RLIMIT_NPROC, 1);
return 0;
}
subsys_initcall(user_namespace_sysctl_init);
projects / linux-2.6-microblaze.git / blobdiff