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https://github.com/torvalds/linux
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dc55e35f9e
Right now, the mqueue sysctls take ipc namespaces into account in a rather hacky way. This works in most cases, but does not respect the user namespace. Within the user namespace, the user cannot change the /proc/sys/fs/mqueue/* parametres. This poses a problem in the rootless containers. To solve this I changed the implementation of the mqueue sysctls just like some other sysctls. So far, the changes do not provide additional access to files. This will be done in a future patch. v3: * Don't implemenet set_permissions to keep the current behavior. v2: * Fixed compilation problem if CONFIG_POSIX_MQUEUE_SYSCTL is not specified. Reported-by: kernel test robot <lkp@intel.com> Signed-off-by: Alexey Gladkov <legion@kernel.org> Link: https://lkml.kernel.org/r/b0ccbb2489119f1f20c737cf1930c3a9c4e4243a.1644862280.git.legion@kernel.org Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
132 lines
3 KiB
C
132 lines
3 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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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 struct ctl_table_root set_root = {
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.lookup = set_lookup,
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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, "fs/mqueue", tbl);
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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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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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