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TOMOYO Linux Cross Reference
Linux/kernel/ucount.c

Version: ~ [ linux-6.11.5 ] ~ [ linux-6.10.14 ] ~ [ linux-6.9.12 ] ~ [ linux-6.8.12 ] ~ [ linux-6.7.12 ] ~ [ linux-6.6.58 ] ~ [ linux-6.5.13 ] ~ [ linux-6.4.16 ] ~ [ linux-6.3.13 ] ~ [ linux-6.2.16 ] ~ [ linux-6.1.114 ] ~ [ linux-6.0.19 ] ~ [ linux-5.19.17 ] ~ [ linux-5.18.19 ] ~ [ linux-5.17.15 ] ~ [ linux-5.16.20 ] ~ [ linux-5.15.169 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.228 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.284 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.322 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.336 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.337 ] ~ [ linux-4.4.302 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.9 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

Diff markup

Differences between /kernel/ucount.c (Architecture ppc) and /kernel/ucount.c (Architecture i386)


  1 // SPDX-License-Identifier: GPL-2.0-only            1 // SPDX-License-Identifier: GPL-2.0-only
  2                                                     2 
  3 #include <linux/stat.h>                             3 #include <linux/stat.h>
  4 #include <linux/sysctl.h>                           4 #include <linux/sysctl.h>
  5 #include <linux/slab.h>                             5 #include <linux/slab.h>
  6 #include <linux/cred.h>                             6 #include <linux/cred.h>
  7 #include <linux/hash.h>                             7 #include <linux/hash.h>
  8 #include <linux/kmemleak.h>                         8 #include <linux/kmemleak.h>
  9 #include <linux/user_namespace.h>                   9 #include <linux/user_namespace.h>
 10                                                    10 
 11 struct ucounts init_ucounts = {                    11 struct ucounts init_ucounts = {
 12         .ns    = &init_user_ns,                    12         .ns    = &init_user_ns,
 13         .uid   = GLOBAL_ROOT_UID,                  13         .uid   = GLOBAL_ROOT_UID,
 14         .count = ATOMIC_INIT(1),                   14         .count = ATOMIC_INIT(1),
 15 };                                                 15 };
 16                                                    16 
 17 #define UCOUNTS_HASHTABLE_BITS 10                  17 #define UCOUNTS_HASHTABLE_BITS 10
 18 static struct hlist_head ucounts_hashtable[(1      18 static struct hlist_head ucounts_hashtable[(1 << UCOUNTS_HASHTABLE_BITS)];
 19 static DEFINE_SPINLOCK(ucounts_lock);              19 static DEFINE_SPINLOCK(ucounts_lock);
 20                                                    20 
 21 #define ucounts_hashfn(ns, uid)                    21 #define ucounts_hashfn(ns, uid)                                         \
 22         hash_long((unsigned long)__kuid_val(ui     22         hash_long((unsigned long)__kuid_val(uid) + (unsigned long)(ns), \
 23                   UCOUNTS_HASHTABLE_BITS)          23                   UCOUNTS_HASHTABLE_BITS)
 24 #define ucounts_hashentry(ns, uid)      \          24 #define ucounts_hashentry(ns, uid)      \
 25         (ucounts_hashtable + ucounts_hashfn(ns     25         (ucounts_hashtable + ucounts_hashfn(ns, uid))
 26                                                    26 
 27                                                    27 
 28 #ifdef CONFIG_SYSCTL                               28 #ifdef CONFIG_SYSCTL
 29 static struct ctl_table_set *                      29 static struct ctl_table_set *
 30 set_lookup(struct ctl_table_root *root)            30 set_lookup(struct ctl_table_root *root)
 31 {                                                  31 {
 32         return &current_user_ns()->set;            32         return &current_user_ns()->set;
 33 }                                                  33 }
 34                                                    34 
 35 static int set_is_seen(struct ctl_table_set *s     35 static int set_is_seen(struct ctl_table_set *set)
 36 {                                                  36 {
 37         return &current_user_ns()->set == set;     37         return &current_user_ns()->set == set;
 38 }                                                  38 }
 39                                                    39 
 40 static int set_permissions(struct ctl_table_he     40 static int set_permissions(struct ctl_table_header *head,
 41                            const struct ctl_ta     41                            const struct ctl_table *table)
 42 {                                                  42 {
 43         struct user_namespace *user_ns =           43         struct user_namespace *user_ns =
 44                 container_of(head->set, struct     44                 container_of(head->set, struct user_namespace, set);
 45         int mode;                                  45         int mode;
 46                                                    46 
 47         /* Allow users with CAP_SYS_RESOURCE u     47         /* Allow users with CAP_SYS_RESOURCE unrestrained access */
 48         if (ns_capable(user_ns, CAP_SYS_RESOUR     48         if (ns_capable(user_ns, CAP_SYS_RESOURCE))
 49                 mode = (table->mode & S_IRWXU)     49                 mode = (table->mode & S_IRWXU) >> 6;
 50         else                                       50         else
 51         /* Allow all others at most read-only      51         /* Allow all others at most read-only access */
 52                 mode = table->mode & S_IROTH;      52                 mode = table->mode & S_IROTH;
 53         return (mode << 6) | (mode << 3) | mod     53         return (mode << 6) | (mode << 3) | mode;
 54 }                                                  54 }
 55                                                    55 
 56 static struct ctl_table_root set_root = {          56 static struct ctl_table_root set_root = {
 57         .lookup = set_lookup,                      57         .lookup = set_lookup,
 58         .permissions = set_permissions,            58         .permissions = set_permissions,
 59 };                                                 59 };
 60                                                    60 
 61 static long ue_zero = 0;                           61 static long ue_zero = 0;
 62 static long ue_int_max = INT_MAX;                  62 static long ue_int_max = INT_MAX;
 63                                                    63 
 64 #define UCOUNT_ENTRY(name)                         64 #define UCOUNT_ENTRY(name)                                      \
 65         {                                          65         {                                                       \
 66                 .procname       = name,            66                 .procname       = name,                         \
 67                 .maxlen         = sizeof(long)     67                 .maxlen         = sizeof(long),                 \
 68                 .mode           = 0644,            68                 .mode           = 0644,                         \
 69                 .proc_handler   = proc_doulong     69                 .proc_handler   = proc_doulongvec_minmax,       \
 70                 .extra1         = &ue_zero,        70                 .extra1         = &ue_zero,                     \
 71                 .extra2         = &ue_int_max,     71                 .extra2         = &ue_int_max,                  \
 72         }                                          72         }
 73 static struct ctl_table user_table[] = {           73 static struct ctl_table user_table[] = {
 74         UCOUNT_ENTRY("max_user_namespaces"),       74         UCOUNT_ENTRY("max_user_namespaces"),
 75         UCOUNT_ENTRY("max_pid_namespaces"),        75         UCOUNT_ENTRY("max_pid_namespaces"),
 76         UCOUNT_ENTRY("max_uts_namespaces"),        76         UCOUNT_ENTRY("max_uts_namespaces"),
 77         UCOUNT_ENTRY("max_ipc_namespaces"),        77         UCOUNT_ENTRY("max_ipc_namespaces"),
 78         UCOUNT_ENTRY("max_net_namespaces"),        78         UCOUNT_ENTRY("max_net_namespaces"),
 79         UCOUNT_ENTRY("max_mnt_namespaces"),        79         UCOUNT_ENTRY("max_mnt_namespaces"),
 80         UCOUNT_ENTRY("max_cgroup_namespaces"),     80         UCOUNT_ENTRY("max_cgroup_namespaces"),
 81         UCOUNT_ENTRY("max_time_namespaces"),       81         UCOUNT_ENTRY("max_time_namespaces"),
 82 #ifdef CONFIG_INOTIFY_USER                         82 #ifdef CONFIG_INOTIFY_USER
 83         UCOUNT_ENTRY("max_inotify_instances"),     83         UCOUNT_ENTRY("max_inotify_instances"),
 84         UCOUNT_ENTRY("max_inotify_watches"),       84         UCOUNT_ENTRY("max_inotify_watches"),
 85 #endif                                             85 #endif
 86 #ifdef CONFIG_FANOTIFY                             86 #ifdef CONFIG_FANOTIFY
 87         UCOUNT_ENTRY("max_fanotify_groups"),       87         UCOUNT_ENTRY("max_fanotify_groups"),
 88         UCOUNT_ENTRY("max_fanotify_marks"),        88         UCOUNT_ENTRY("max_fanotify_marks"),
 89 #endif                                             89 #endif
 90 };                                                 90 };
 91 #endif /* CONFIG_SYSCTL */                         91 #endif /* CONFIG_SYSCTL */
 92                                                    92 
 93 bool setup_userns_sysctls(struct user_namespac     93 bool setup_userns_sysctls(struct user_namespace *ns)
 94 {                                                  94 {
 95 #ifdef CONFIG_SYSCTL                               95 #ifdef CONFIG_SYSCTL
 96         struct ctl_table *tbl;                     96         struct ctl_table *tbl;
 97                                                    97 
 98         BUILD_BUG_ON(ARRAY_SIZE(user_table) !=     98         BUILD_BUG_ON(ARRAY_SIZE(user_table) != UCOUNT_COUNTS);
 99         setup_sysctl_set(&ns->set, &set_root,      99         setup_sysctl_set(&ns->set, &set_root, set_is_seen);
100         tbl = kmemdup(user_table, sizeof(user_    100         tbl = kmemdup(user_table, sizeof(user_table), GFP_KERNEL);
101         if (tbl) {                                101         if (tbl) {
102                 int i;                            102                 int i;
103                 for (i = 0; i < UCOUNT_COUNTS;    103                 for (i = 0; i < UCOUNT_COUNTS; i++) {
104                         tbl[i].data = &ns->uco    104                         tbl[i].data = &ns->ucount_max[i];
105                 }                                 105                 }
106                 ns->sysctls = __register_sysct    106                 ns->sysctls = __register_sysctl_table(&ns->set, "user", tbl,
107                                                   107                                                       ARRAY_SIZE(user_table));
108         }                                         108         }
109         if (!ns->sysctls) {                       109         if (!ns->sysctls) {
110                 kfree(tbl);                       110                 kfree(tbl);
111                 retire_sysctl_set(&ns->set);      111                 retire_sysctl_set(&ns->set);
112                 return false;                     112                 return false;
113         }                                         113         }
114 #endif                                            114 #endif
115         return true;                              115         return true;
116 }                                                 116 }
117                                                   117 
118 void retire_userns_sysctls(struct user_namespa    118 void retire_userns_sysctls(struct user_namespace *ns)
119 {                                                 119 {
120 #ifdef CONFIG_SYSCTL                              120 #ifdef CONFIG_SYSCTL
121         const struct ctl_table *tbl;              121         const struct ctl_table *tbl;
122                                                   122 
123         tbl = ns->sysctls->ctl_table_arg;         123         tbl = ns->sysctls->ctl_table_arg;
124         unregister_sysctl_table(ns->sysctls);     124         unregister_sysctl_table(ns->sysctls);
125         retire_sysctl_set(&ns->set);              125         retire_sysctl_set(&ns->set);
126         kfree(tbl);                               126         kfree(tbl);
127 #endif                                            127 #endif
128 }                                                 128 }
129                                                   129 
130 static struct ucounts *find_ucounts(struct use    130 static struct ucounts *find_ucounts(struct user_namespace *ns, kuid_t uid, struct hlist_head *hashent)
131 {                                                 131 {
132         struct ucounts *ucounts;                  132         struct ucounts *ucounts;
133                                                   133 
134         hlist_for_each_entry(ucounts, hashent,    134         hlist_for_each_entry(ucounts, hashent, node) {
135                 if (uid_eq(ucounts->uid, uid)     135                 if (uid_eq(ucounts->uid, uid) && (ucounts->ns == ns))
136                         return ucounts;           136                         return ucounts;
137         }                                         137         }
138         return NULL;                              138         return NULL;
139 }                                                 139 }
140                                                   140 
141 static void hlist_add_ucounts(struct ucounts *    141 static void hlist_add_ucounts(struct ucounts *ucounts)
142 {                                                 142 {
143         struct hlist_head *hashent = ucounts_h    143         struct hlist_head *hashent = ucounts_hashentry(ucounts->ns, ucounts->uid);
144         spin_lock_irq(&ucounts_lock);             144         spin_lock_irq(&ucounts_lock);
145         hlist_add_head(&ucounts->node, hashent    145         hlist_add_head(&ucounts->node, hashent);
146         spin_unlock_irq(&ucounts_lock);           146         spin_unlock_irq(&ucounts_lock);
147 }                                                 147 }
148                                                   148 
149 static inline bool get_ucounts_or_wrap(struct     149 static inline bool get_ucounts_or_wrap(struct ucounts *ucounts)
150 {                                                 150 {
151         /* Returns true on a successful get, f    151         /* Returns true on a successful get, false if the count wraps. */
152         return !atomic_add_negative(1, &ucount    152         return !atomic_add_negative(1, &ucounts->count);
153 }                                                 153 }
154                                                   154 
155 struct ucounts *get_ucounts(struct ucounts *uc    155 struct ucounts *get_ucounts(struct ucounts *ucounts)
156 {                                                 156 {
157         if (!get_ucounts_or_wrap(ucounts)) {      157         if (!get_ucounts_or_wrap(ucounts)) {
158                 put_ucounts(ucounts);             158                 put_ucounts(ucounts);
159                 ucounts = NULL;                   159                 ucounts = NULL;
160         }                                         160         }
161         return ucounts;                           161         return ucounts;
162 }                                                 162 }
163                                                   163 
164 struct ucounts *alloc_ucounts(struct user_name    164 struct ucounts *alloc_ucounts(struct user_namespace *ns, kuid_t uid)
165 {                                                 165 {
166         struct hlist_head *hashent = ucounts_h    166         struct hlist_head *hashent = ucounts_hashentry(ns, uid);
167         struct ucounts *ucounts, *new;            167         struct ucounts *ucounts, *new;
168         bool wrapped;                             168         bool wrapped;
169                                                   169 
170         spin_lock_irq(&ucounts_lock);             170         spin_lock_irq(&ucounts_lock);
171         ucounts = find_ucounts(ns, uid, hashen    171         ucounts = find_ucounts(ns, uid, hashent);
172         if (!ucounts) {                           172         if (!ucounts) {
173                 spin_unlock_irq(&ucounts_lock)    173                 spin_unlock_irq(&ucounts_lock);
174                                                   174 
175                 new = kzalloc(sizeof(*new), GF    175                 new = kzalloc(sizeof(*new), GFP_KERNEL);
176                 if (!new)                         176                 if (!new)
177                         return NULL;              177                         return NULL;
178                                                   178 
179                 new->ns = ns;                     179                 new->ns = ns;
180                 new->uid = uid;                   180                 new->uid = uid;
181                 atomic_set(&new->count, 1);       181                 atomic_set(&new->count, 1);
182                                                   182 
183                 spin_lock_irq(&ucounts_lock);     183                 spin_lock_irq(&ucounts_lock);
184                 ucounts = find_ucounts(ns, uid    184                 ucounts = find_ucounts(ns, uid, hashent);
185                 if (ucounts) {                    185                 if (ucounts) {
186                         kfree(new);               186                         kfree(new);
187                 } else {                          187                 } else {
188                         hlist_add_head(&new->n    188                         hlist_add_head(&new->node, hashent);
189                         get_user_ns(new->ns);     189                         get_user_ns(new->ns);
190                         spin_unlock_irq(&ucoun    190                         spin_unlock_irq(&ucounts_lock);
191                         return new;               191                         return new;
192                 }                                 192                 }
193         }                                         193         }
194         wrapped = !get_ucounts_or_wrap(ucounts    194         wrapped = !get_ucounts_or_wrap(ucounts);
195         spin_unlock_irq(&ucounts_lock);           195         spin_unlock_irq(&ucounts_lock);
196         if (wrapped) {                            196         if (wrapped) {
197                 put_ucounts(ucounts);             197                 put_ucounts(ucounts);
198                 return NULL;                      198                 return NULL;
199         }                                         199         }
200         return ucounts;                           200         return ucounts;
201 }                                                 201 }
202                                                   202 
203 void put_ucounts(struct ucounts *ucounts)         203 void put_ucounts(struct ucounts *ucounts)
204 {                                                 204 {
205         unsigned long flags;                      205         unsigned long flags;
206                                                   206 
207         if (atomic_dec_and_lock_irqsave(&ucoun    207         if (atomic_dec_and_lock_irqsave(&ucounts->count, &ucounts_lock, flags)) {
208                 hlist_del_init(&ucounts->node)    208                 hlist_del_init(&ucounts->node);
209                 spin_unlock_irqrestore(&ucount    209                 spin_unlock_irqrestore(&ucounts_lock, flags);
210                 put_user_ns(ucounts->ns);         210                 put_user_ns(ucounts->ns);
211                 kfree(ucounts);                   211                 kfree(ucounts);
212         }                                         212         }
213 }                                                 213 }
214                                                   214 
215 static inline bool atomic_long_inc_below(atomi    215 static inline bool atomic_long_inc_below(atomic_long_t *v, int u)
216 {                                                 216 {
217         long c, old;                              217         long c, old;
218         c = atomic_long_read(v);                  218         c = atomic_long_read(v);
219         for (;;) {                                219         for (;;) {
220                 if (unlikely(c >= u))             220                 if (unlikely(c >= u))
221                         return false;             221                         return false;
222                 old = atomic_long_cmpxchg(v, c    222                 old = atomic_long_cmpxchg(v, c, c+1);
223                 if (likely(old == c))             223                 if (likely(old == c))
224                         return true;              224                         return true;
225                 c = old;                          225                 c = old;
226         }                                         226         }
227 }                                                 227 }
228                                                   228 
229 struct ucounts *inc_ucount(struct user_namespa    229 struct ucounts *inc_ucount(struct user_namespace *ns, kuid_t uid,
230                            enum ucount_type ty    230                            enum ucount_type type)
231 {                                                 231 {
232         struct ucounts *ucounts, *iter, *bad;     232         struct ucounts *ucounts, *iter, *bad;
233         struct user_namespace *tns;               233         struct user_namespace *tns;
234         ucounts = alloc_ucounts(ns, uid);         234         ucounts = alloc_ucounts(ns, uid);
235         for (iter = ucounts; iter; iter = tns-    235         for (iter = ucounts; iter; iter = tns->ucounts) {
236                 long max;                         236                 long max;
237                 tns = iter->ns;                   237                 tns = iter->ns;
238                 max = READ_ONCE(tns->ucount_ma    238                 max = READ_ONCE(tns->ucount_max[type]);
239                 if (!atomic_long_inc_below(&it    239                 if (!atomic_long_inc_below(&iter->ucount[type], max))
240                         goto fail;                240                         goto fail;
241         }                                         241         }
242         return ucounts;                           242         return ucounts;
243 fail:                                             243 fail:
244         bad = iter;                               244         bad = iter;
245         for (iter = ucounts; iter != bad; iter    245         for (iter = ucounts; iter != bad; iter = iter->ns->ucounts)
246                 atomic_long_dec(&iter->ucount[    246                 atomic_long_dec(&iter->ucount[type]);
247                                                   247 
248         put_ucounts(ucounts);                     248         put_ucounts(ucounts);
249         return NULL;                              249         return NULL;
250 }                                                 250 }
251                                                   251 
252 void dec_ucount(struct ucounts *ucounts, enum     252 void dec_ucount(struct ucounts *ucounts, enum ucount_type type)
253 {                                                 253 {
254         struct ucounts *iter;                     254         struct ucounts *iter;
255         for (iter = ucounts; iter; iter = iter    255         for (iter = ucounts; iter; iter = iter->ns->ucounts) {
256                 long dec = atomic_long_dec_if_    256                 long dec = atomic_long_dec_if_positive(&iter->ucount[type]);
257                 WARN_ON_ONCE(dec < 0);            257                 WARN_ON_ONCE(dec < 0);
258         }                                         258         }
259         put_ucounts(ucounts);                     259         put_ucounts(ucounts);
260 }                                                 260 }
261                                                   261 
262 long inc_rlimit_ucounts(struct ucounts *ucount    262 long inc_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
263 {                                                 263 {
264         struct ucounts *iter;                     264         struct ucounts *iter;
265         long max = LONG_MAX;                      265         long max = LONG_MAX;
266         long ret = 0;                             266         long ret = 0;
267                                                   267 
268         for (iter = ucounts; iter; iter = iter    268         for (iter = ucounts; iter; iter = iter->ns->ucounts) {
269                 long new = atomic_long_add_ret    269                 long new = atomic_long_add_return(v, &iter->rlimit[type]);
270                 if (new < 0 || new > max)         270                 if (new < 0 || new > max)
271                         ret = LONG_MAX;           271                         ret = LONG_MAX;
272                 else if (iter == ucounts)         272                 else if (iter == ucounts)
273                         ret = new;                273                         ret = new;
274                 max = get_userns_rlimit_max(it    274                 max = get_userns_rlimit_max(iter->ns, type);
275         }                                         275         }
276         return ret;                               276         return ret;
277 }                                                 277 }
278                                                   278 
279 bool dec_rlimit_ucounts(struct ucounts *ucount    279 bool dec_rlimit_ucounts(struct ucounts *ucounts, enum rlimit_type type, long v)
280 {                                                 280 {
281         struct ucounts *iter;                     281         struct ucounts *iter;
282         long new = -1; /* Silence compiler war    282         long new = -1; /* Silence compiler warning */
283         for (iter = ucounts; iter; iter = iter    283         for (iter = ucounts; iter; iter = iter->ns->ucounts) {
284                 long dec = atomic_long_sub_ret    284                 long dec = atomic_long_sub_return(v, &iter->rlimit[type]);
285                 WARN_ON_ONCE(dec < 0);            285                 WARN_ON_ONCE(dec < 0);
286                 if (iter == ucounts)              286                 if (iter == ucounts)
287                         new = dec;                287                         new = dec;
288         }                                         288         }
289         return (new == 0);                        289         return (new == 0);
290 }                                                 290 }
291                                                   291 
292 static void do_dec_rlimit_put_ucounts(struct u    292 static void do_dec_rlimit_put_ucounts(struct ucounts *ucounts,
293                                 struct ucounts    293                                 struct ucounts *last, enum rlimit_type type)
294 {                                                 294 {
295         struct ucounts *iter, *next;              295         struct ucounts *iter, *next;
296         for (iter = ucounts; iter != last; ite    296         for (iter = ucounts; iter != last; iter = next) {
297                 long dec = atomic_long_sub_ret    297                 long dec = atomic_long_sub_return(1, &iter->rlimit[type]);
298                 WARN_ON_ONCE(dec < 0);            298                 WARN_ON_ONCE(dec < 0);
299                 next = iter->ns->ucounts;         299                 next = iter->ns->ucounts;
300                 if (dec == 0)                     300                 if (dec == 0)
301                         put_ucounts(iter);        301                         put_ucounts(iter);
302         }                                         302         }
303 }                                                 303 }
304                                                   304 
305 void dec_rlimit_put_ucounts(struct ucounts *uc    305 void dec_rlimit_put_ucounts(struct ucounts *ucounts, enum rlimit_type type)
306 {                                                 306 {
307         do_dec_rlimit_put_ucounts(ucounts, NUL    307         do_dec_rlimit_put_ucounts(ucounts, NULL, type);
308 }                                                 308 }
309                                                   309 
310 long inc_rlimit_get_ucounts(struct ucounts *uc    310 long inc_rlimit_get_ucounts(struct ucounts *ucounts, enum rlimit_type type)
311 {                                                 311 {
312         /* Caller must hold a reference to uco    312         /* Caller must hold a reference to ucounts */
313         struct ucounts *iter;                     313         struct ucounts *iter;
314         long max = LONG_MAX;                      314         long max = LONG_MAX;
315         long dec, ret = 0;                        315         long dec, ret = 0;
316                                                   316 
317         for (iter = ucounts; iter; iter = iter    317         for (iter = ucounts; iter; iter = iter->ns->ucounts) {
318                 long new = atomic_long_add_ret    318                 long new = atomic_long_add_return(1, &iter->rlimit[type]);
319                 if (new < 0 || new > max)         319                 if (new < 0 || new > max)
320                         goto unwind;              320                         goto unwind;
321                 if (iter == ucounts)              321                 if (iter == ucounts)
322                         ret = new;                322                         ret = new;
323                 max = get_userns_rlimit_max(it    323                 max = get_userns_rlimit_max(iter->ns, type);
324                 /*                                324                 /*
325                  * Grab an extra ucount refere    325                  * Grab an extra ucount reference for the caller when
326                  * the rlimit count was previo    326                  * the rlimit count was previously 0.
327                  */                               327                  */
328                 if (new != 1)                     328                 if (new != 1)
329                         continue;                 329                         continue;
330                 if (!get_ucounts(iter))           330                 if (!get_ucounts(iter))
331                         goto dec_unwind;          331                         goto dec_unwind;
332         }                                         332         }
333         return ret;                               333         return ret;
334 dec_unwind:                                       334 dec_unwind:
335         dec = atomic_long_sub_return(1, &iter-    335         dec = atomic_long_sub_return(1, &iter->rlimit[type]);
336         WARN_ON_ONCE(dec < 0);                    336         WARN_ON_ONCE(dec < 0);
337 unwind:                                           337 unwind:
338         do_dec_rlimit_put_ucounts(ucounts, ite    338         do_dec_rlimit_put_ucounts(ucounts, iter, type);
339         return 0;                                 339         return 0;
340 }                                                 340 }
341                                                   341 
342 bool is_rlimit_overlimit(struct ucounts *ucoun    342 bool is_rlimit_overlimit(struct ucounts *ucounts, enum rlimit_type type, unsigned long rlimit)
343 {                                                 343 {
344         struct ucounts *iter;                     344         struct ucounts *iter;
345         long max = rlimit;                        345         long max = rlimit;
346         if (rlimit > LONG_MAX)                    346         if (rlimit > LONG_MAX)
347                 max = LONG_MAX;                   347                 max = LONG_MAX;
348         for (iter = ucounts; iter; iter = iter    348         for (iter = ucounts; iter; iter = iter->ns->ucounts) {
349                 long val = get_rlimit_value(it    349                 long val = get_rlimit_value(iter, type);
350                 if (val < 0 || val > max)         350                 if (val < 0 || val > max)
351                         return true;              351                         return true;
352                 max = get_userns_rlimit_max(it    352                 max = get_userns_rlimit_max(iter->ns, type);
353         }                                         353         }
354         return false;                             354         return false;
355 }                                                 355 }
356                                                   356 
357 static __init int user_namespace_sysctl_init(v    357 static __init int user_namespace_sysctl_init(void)
358 {                                                 358 {
359 #ifdef CONFIG_SYSCTL                              359 #ifdef CONFIG_SYSCTL
360         static struct ctl_table_header *user_h    360         static struct ctl_table_header *user_header;
361         static struct ctl_table empty[1];         361         static struct ctl_table empty[1];
362         /*                                        362         /*
363          * It is necessary to register the use    363          * It is necessary to register the user directory in the
364          * default set so that registrations i    364          * default set so that registrations in the child sets work
365          * properly.                              365          * properly.
366          */                                       366          */
367         user_header = register_sysctl_sz("user    367         user_header = register_sysctl_sz("user", empty, 0);
368         kmemleak_ignore(user_header);             368         kmemleak_ignore(user_header);
369         BUG_ON(!user_header);                     369         BUG_ON(!user_header);
370         BUG_ON(!setup_userns_sysctls(&init_use    370         BUG_ON(!setup_userns_sysctls(&init_user_ns));
371 #endif                                            371 #endif
372         hlist_add_ucounts(&init_ucounts);         372         hlist_add_ucounts(&init_ucounts);
373         inc_rlimit_ucounts(&init_ucounts, UCOU    373         inc_rlimit_ucounts(&init_ucounts, UCOUNT_RLIMIT_NPROC, 1);
374         return 0;                                 374         return 0;
375 }                                                 375 }
376 subsys_initcall(user_namespace_sysctl_init);      376 subsys_initcall(user_namespace_sysctl_init);
377                                                   377 

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