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To be able to constify instances of struct ctl_tables it is necessary to remove ways through which non-const versions are exposed from the sysctl core. One of these is the ctl_table_arg member of struct ctl_table_header. Constify this reference as a prerequisite for the full constification of struct ctl_table instances. No functional change. Signed-off-by: Thomas Weißschuh <linux@weissschuh.net> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: David S. Miller <davem@davemloft.net>
170 lines
3.9 KiB
C
170 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2007 IBM Corporation
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*
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* Author: Cedric Le Goater <clg@fr.ibm.com>
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*/
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#include <linux/nsproxy.h>
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#include <linux/ipc_namespace.h>
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#include <linux/sysctl.h>
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#include <linux/stat.h>
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#include <linux/capability.h>
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#include <linux/slab.h>
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#include <linux/cred.h>
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static int msg_max_limit_min = MIN_MSGMAX;
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static int msg_max_limit_max = HARD_MSGMAX;
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static int msg_maxsize_limit_min = MIN_MSGSIZEMAX;
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static int msg_maxsize_limit_max = HARD_MSGSIZEMAX;
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static struct ctl_table mq_sysctls[] = {
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{
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.procname = "queues_max",
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.data = &init_ipc_ns.mq_queues_max,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec,
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},
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{
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.procname = "msg_max",
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.data = &init_ipc_ns.mq_msg_max,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = &msg_max_limit_min,
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.extra2 = &msg_max_limit_max,
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},
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{
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.procname = "msgsize_max",
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.data = &init_ipc_ns.mq_msgsize_max,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = &msg_maxsize_limit_min,
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.extra2 = &msg_maxsize_limit_max,
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},
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{
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.procname = "msg_default",
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.data = &init_ipc_ns.mq_msg_default,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = &msg_max_limit_min,
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.extra2 = &msg_max_limit_max,
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},
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{
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.procname = "msgsize_default",
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.data = &init_ipc_ns.mq_msgsize_default,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = &msg_maxsize_limit_min,
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.extra2 = &msg_maxsize_limit_max,
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},
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{}
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};
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static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
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{
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return ¤t->nsproxy->ipc_ns->mq_set;
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}
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static int set_is_seen(struct ctl_table_set *set)
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{
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return ¤t->nsproxy->ipc_ns->mq_set == set;
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}
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static void mq_set_ownership(struct ctl_table_header *head,
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struct ctl_table *table,
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kuid_t *uid, kgid_t *gid)
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{
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struct ipc_namespace *ns =
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container_of(head->set, struct ipc_namespace, mq_set);
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kuid_t ns_root_uid = make_kuid(ns->user_ns, 0);
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kgid_t ns_root_gid = make_kgid(ns->user_ns, 0);
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*uid = uid_valid(ns_root_uid) ? ns_root_uid : GLOBAL_ROOT_UID;
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*gid = gid_valid(ns_root_gid) ? ns_root_gid : GLOBAL_ROOT_GID;
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}
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static int mq_permissions(struct ctl_table_header *head, struct ctl_table *table)
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{
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int mode = table->mode;
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kuid_t ns_root_uid;
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kgid_t ns_root_gid;
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mq_set_ownership(head, table, &ns_root_uid, &ns_root_gid);
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if (uid_eq(current_euid(), ns_root_uid))
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mode >>= 6;
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else if (in_egroup_p(ns_root_gid))
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mode >>= 3;
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mode &= 7;
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return (mode << 6) | (mode << 3) | mode;
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}
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static struct ctl_table_root set_root = {
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.lookup = set_lookup,
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.permissions = mq_permissions,
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.set_ownership = mq_set_ownership,
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};
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bool setup_mq_sysctls(struct ipc_namespace *ns)
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{
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struct ctl_table *tbl;
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setup_sysctl_set(&ns->mq_set, &set_root, set_is_seen);
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tbl = kmemdup(mq_sysctls, sizeof(mq_sysctls), GFP_KERNEL);
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if (tbl) {
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int i;
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for (i = 0; i < ARRAY_SIZE(mq_sysctls); i++) {
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if (tbl[i].data == &init_ipc_ns.mq_queues_max)
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tbl[i].data = &ns->mq_queues_max;
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else if (tbl[i].data == &init_ipc_ns.mq_msg_max)
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tbl[i].data = &ns->mq_msg_max;
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else if (tbl[i].data == &init_ipc_ns.mq_msgsize_max)
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tbl[i].data = &ns->mq_msgsize_max;
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else if (tbl[i].data == &init_ipc_ns.mq_msg_default)
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tbl[i].data = &ns->mq_msg_default;
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else if (tbl[i].data == &init_ipc_ns.mq_msgsize_default)
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tbl[i].data = &ns->mq_msgsize_default;
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else
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tbl[i].data = NULL;
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}
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ns->mq_sysctls = __register_sysctl_table(&ns->mq_set,
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"fs/mqueue", tbl,
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ARRAY_SIZE(mq_sysctls));
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}
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if (!ns->mq_sysctls) {
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kfree(tbl);
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retire_sysctl_set(&ns->mq_set);
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return false;
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}
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return true;
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}
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void retire_mq_sysctls(struct ipc_namespace *ns)
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{
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const struct ctl_table *tbl;
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tbl = ns->mq_sysctls->ctl_table_arg;
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unregister_sysctl_table(ns->mq_sysctls);
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retire_sysctl_set(&ns->mq_set);
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kfree(tbl);
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}
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