1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2007 4 * 5 * Author: Eric Biederman <ebiederm@xmision.com> 6 */ 7 8 #include <linux/module.h> 9 #include <linux/ipc.h> 10 #include <linux/nsproxy.h> 11 #include <linux/sysctl.h> 12 #include <linux/uaccess.h> 13 #include <linux/capability.h> 14 #include <linux/ipc_namespace.h> 15 #include <linux/msg.h> 16 #include <linux/slab.h> 17 #include <linux/cred.h> 18 #include "util.h" 19 20 static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write, 21 void *buffer, size_t *lenp, loff_t *ppos) 22 { 23 struct ipc_namespace *ns = 24 container_of(table->data, struct ipc_namespace, shm_rmid_forced); 25 int err; 26 27 err = proc_dointvec_minmax(table, write, buffer, lenp, ppos); 28 29 if (err < 0) 30 return err; 31 if (ns->shm_rmid_forced) 32 shm_destroy_orphaned(ns); 33 return err; 34 } 35 36 static int proc_ipc_auto_msgmni(struct ctl_table *table, int write, 37 void *buffer, size_t *lenp, loff_t *ppos) 38 { 39 struct ctl_table ipc_table; 40 int dummy = 0; 41 42 memcpy(&ipc_table, table, sizeof(ipc_table)); 43 ipc_table.data = &dummy; 44 45 if (write) 46 pr_info_once("writing to auto_msgmni has no effect"); 47 48 return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos); 49 } 50 51 static int proc_ipc_sem_dointvec(struct ctl_table *table, int write, 52 void *buffer, size_t *lenp, loff_t *ppos) 53 { 54 struct ipc_namespace *ns = 55 container_of(table->data, struct ipc_namespace, sem_ctls); 56 int ret, semmni; 57 58 semmni = ns->sem_ctls[3]; 59 ret = proc_dointvec(table, write, buffer, lenp, ppos); 60 61 if (!ret) 62 ret = sem_check_semmni(ns); 63 64 /* 65 * Reset the semmni value if an error happens. 66 */ 67 if (ret) 68 ns->sem_ctls[3] = semmni; 69 return ret; 70 } 71 72 int ipc_mni = IPCMNI; 73 int ipc_mni_shift = IPCMNI_SHIFT; 74 int ipc_min_cycle = RADIX_TREE_MAP_SIZE; 75 76 static struct ctl_table ipc_sysctls[] = { 77 { 78 .procname = "shmmax", 79 .data = &init_ipc_ns.shm_ctlmax, 80 .maxlen = sizeof(init_ipc_ns.shm_ctlmax), 81 .mode = 0644, 82 .proc_handler = proc_doulongvec_minmax, 83 }, 84 { 85 .procname = "shmall", 86 .data = &init_ipc_ns.shm_ctlall, 87 .maxlen = sizeof(init_ipc_ns.shm_ctlall), 88 .mode = 0644, 89 .proc_handler = proc_doulongvec_minmax, 90 }, 91 { 92 .procname = "shmmni", 93 .data = &init_ipc_ns.shm_ctlmni, 94 .maxlen = sizeof(init_ipc_ns.shm_ctlmni), 95 .mode = 0644, 96 .proc_handler = proc_dointvec_minmax, 97 .extra1 = SYSCTL_ZERO, 98 .extra2 = &ipc_mni, 99 }, 100 { 101 .procname = "shm_rmid_forced", 102 .data = &init_ipc_ns.shm_rmid_forced, 103 .maxlen = sizeof(init_ipc_ns.shm_rmid_forced), 104 .mode = 0644, 105 .proc_handler = proc_ipc_dointvec_minmax_orphans, 106 .extra1 = SYSCTL_ZERO, 107 .extra2 = SYSCTL_ONE, 108 }, 109 { 110 .procname = "msgmax", 111 .data = &init_ipc_ns.msg_ctlmax, 112 .maxlen = sizeof(init_ipc_ns.msg_ctlmax), 113 .mode = 0644, 114 .proc_handler = proc_dointvec_minmax, 115 .extra1 = SYSCTL_ZERO, 116 .extra2 = SYSCTL_INT_MAX, 117 }, 118 { 119 .procname = "msgmni", 120 .data = &init_ipc_ns.msg_ctlmni, 121 .maxlen = sizeof(init_ipc_ns.msg_ctlmni), 122 .mode = 0644, 123 .proc_handler = proc_dointvec_minmax, 124 .extra1 = SYSCTL_ZERO, 125 .extra2 = &ipc_mni, 126 }, 127 { 128 .procname = "auto_msgmni", 129 .data = NULL, 130 .maxlen = sizeof(int), 131 .mode = 0644, 132 .proc_handler = proc_ipc_auto_msgmni, 133 .extra1 = SYSCTL_ZERO, 134 .extra2 = SYSCTL_ONE, 135 }, 136 { 137 .procname = "msgmnb", 138 .data = &init_ipc_ns.msg_ctlmnb, 139 .maxlen = sizeof(init_ipc_ns.msg_ctlmnb), 140 .mode = 0644, 141 .proc_handler = proc_dointvec_minmax, 142 .extra1 = SYSCTL_ZERO, 143 .extra2 = SYSCTL_INT_MAX, 144 }, 145 { 146 .procname = "sem", 147 .data = &init_ipc_ns.sem_ctls, 148 .maxlen = 4*sizeof(int), 149 .mode = 0644, 150 .proc_handler = proc_ipc_sem_dointvec, 151 }, 152 #ifdef CONFIG_CHECKPOINT_RESTORE 153 { 154 .procname = "sem_next_id", 155 .data = &init_ipc_ns.ids[IPC_SEM_IDS].next_id, 156 .maxlen = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id), 157 .mode = 0444, 158 .proc_handler = proc_dointvec_minmax, 159 .extra1 = SYSCTL_ZERO, 160 .extra2 = SYSCTL_INT_MAX, 161 }, 162 { 163 .procname = "msg_next_id", 164 .data = &init_ipc_ns.ids[IPC_MSG_IDS].next_id, 165 .maxlen = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id), 166 .mode = 0444, 167 .proc_handler = proc_dointvec_minmax, 168 .extra1 = SYSCTL_ZERO, 169 .extra2 = SYSCTL_INT_MAX, 170 }, 171 { 172 .procname = "shm_next_id", 173 .data = &init_ipc_ns.ids[IPC_SHM_IDS].next_id, 174 .maxlen = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id), 175 .mode = 0444, 176 .proc_handler = proc_dointvec_minmax, 177 .extra1 = SYSCTL_ZERO, 178 .extra2 = SYSCTL_INT_MAX, 179 }, 180 #endif 181 {} 182 }; 183 184 static struct ctl_table_set *set_lookup(struct ctl_table_root *root) 185 { 186 return ¤t->nsproxy->ipc_ns->ipc_set; 187 } 188 189 static int set_is_seen(struct ctl_table_set *set) 190 { 191 return ¤t->nsproxy->ipc_ns->ipc_set == set; 192 } 193 194 static void ipc_set_ownership(struct ctl_table_header *head, 195 kuid_t *uid, kgid_t *gid) 196 { 197 struct ipc_namespace *ns = 198 container_of(head->set, struct ipc_namespace, ipc_set); 199 200 kuid_t ns_root_uid = make_kuid(ns->user_ns, 0); 201 kgid_t ns_root_gid = make_kgid(ns->user_ns, 0); 202 203 *uid = uid_valid(ns_root_uid) ? ns_root_uid : GLOBAL_ROOT_UID; 204 *gid = gid_valid(ns_root_gid) ? ns_root_gid : GLOBAL_ROOT_GID; 205 } 206 207 static int ipc_permissions(struct ctl_table_header *head, struct ctl_table *table) 208 { 209 int mode = table->mode; 210 211 #ifdef CONFIG_CHECKPOINT_RESTORE 212 struct ipc_namespace *ns = 213 container_of(head->set, struct ipc_namespace, ipc_set); 214 215 if (((table->data == &ns->ids[IPC_SEM_IDS].next_id) || 216 (table->data == &ns->ids[IPC_MSG_IDS].next_id) || 217 (table->data == &ns->ids[IPC_SHM_IDS].next_id)) && 218 checkpoint_restore_ns_capable(ns->user_ns)) 219 mode = 0666; 220 else 221 #endif 222 { 223 kuid_t ns_root_uid; 224 kgid_t ns_root_gid; 225 226 ipc_set_ownership(head, &ns_root_uid, &ns_root_gid); 227 228 if (uid_eq(current_euid(), ns_root_uid)) 229 mode >>= 6; 230 231 else if (in_egroup_p(ns_root_gid)) 232 mode >>= 3; 233 } 234 235 mode &= 7; 236 237 return (mode << 6) | (mode << 3) | mode; 238 } 239 240 static struct ctl_table_root set_root = { 241 .lookup = set_lookup, 242 .permissions = ipc_permissions, 243 .set_ownership = ipc_set_ownership, 244 }; 245 246 bool setup_ipc_sysctls(struct ipc_namespace *ns) 247 { 248 struct ctl_table *tbl; 249 250 setup_sysctl_set(&ns->ipc_set, &set_root, set_is_seen); 251 252 tbl = kmemdup(ipc_sysctls, sizeof(ipc_sysctls), GFP_KERNEL); 253 if (tbl) { 254 int i; 255 256 for (i = 0; i < ARRAY_SIZE(ipc_sysctls); i++) { 257 if (tbl[i].data == &init_ipc_ns.shm_ctlmax) 258 tbl[i].data = &ns->shm_ctlmax; 259 260 else if (tbl[i].data == &init_ipc_ns.shm_ctlall) 261 tbl[i].data = &ns->shm_ctlall; 262 263 else if (tbl[i].data == &init_ipc_ns.shm_ctlmni) 264 tbl[i].data = &ns->shm_ctlmni; 265 266 else if (tbl[i].data == &init_ipc_ns.shm_rmid_forced) 267 tbl[i].data = &ns->shm_rmid_forced; 268 269 else if (tbl[i].data == &init_ipc_ns.msg_ctlmax) 270 tbl[i].data = &ns->msg_ctlmax; 271 272 else if (tbl[i].data == &init_ipc_ns.msg_ctlmni) 273 tbl[i].data = &ns->msg_ctlmni; 274 275 else if (tbl[i].data == &init_ipc_ns.msg_ctlmnb) 276 tbl[i].data = &ns->msg_ctlmnb; 277 278 else if (tbl[i].data == &init_ipc_ns.sem_ctls) 279 tbl[i].data = &ns->sem_ctls; 280 #ifdef CONFIG_CHECKPOINT_RESTORE 281 else if (tbl[i].data == &init_ipc_ns.ids[IPC_SEM_IDS].next_id) 282 tbl[i].data = &ns->ids[IPC_SEM_IDS].next_id; 283 284 else if (tbl[i].data == &init_ipc_ns.ids[IPC_MSG_IDS].next_id) 285 tbl[i].data = &ns->ids[IPC_MSG_IDS].next_id; 286 287 else if (tbl[i].data == &init_ipc_ns.ids[IPC_SHM_IDS].next_id) 288 tbl[i].data = &ns->ids[IPC_SHM_IDS].next_id; 289 #endif 290 else 291 tbl[i].data = NULL; 292 } 293 294 ns->ipc_sysctls = __register_sysctl_table(&ns->ipc_set, 295 "kernel", tbl, 296 ARRAY_SIZE(ipc_sysctls)); 297 } 298 if (!ns->ipc_sysctls) { 299 kfree(tbl); 300 retire_sysctl_set(&ns->ipc_set); 301 return false; 302 } 303 304 return true; 305 } 306 307 void retire_ipc_sysctls(struct ipc_namespace *ns) 308 { 309 struct ctl_table *tbl; 310 311 tbl = ns->ipc_sysctls->ctl_table_arg; 312 unregister_sysctl_table(ns->ipc_sysctls); 313 retire_sysctl_set(&ns->ipc_set); 314 kfree(tbl); 315 } 316 317 static int __init ipc_sysctl_init(void) 318 { 319 if (!setup_ipc_sysctls(&init_ipc_ns)) { 320 pr_warn("ipc sysctl registration failed\n"); 321 return -ENOMEM; 322 } 323 return 0; 324 } 325 326 device_initcall(ipc_sysctl_init); 327 328 static int __init ipc_mni_extend(char *str) 329 { 330 ipc_mni = IPCMNI_EXTEND; 331 ipc_mni_shift = IPCMNI_EXTEND_SHIFT; 332 ipc_min_cycle = IPCMNI_EXTEND_MIN_CYCLE; 333 pr_info("IPCMNI extended to %d.\n", ipc_mni); 334 return 0; 335 } 336 early_param("ipcmni_extend", ipc_mni_extend); 337