From: Alexey Gladkov <legion@kernel.org>
To: LKML <linux-kernel@vger.kernel.org>,
Linux Containers <containers@lists.linux.dev>
Cc: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com>,
Andrew Morton <akpm@linux-foundation.org>,
Christian Brauner <christian.brauner@ubuntu.com>,
Daniel Walsh <dwalsh@redhat.com>,
Davidlohr Bueso <dbueso@suse.de>,
"Eric W . Biederman" <ebiederm@xmission.com>,
Kirill Tkhai <ktkhai@virtuozzo.com>,
Manfred Spraul <manfred@colorfullife.com>,
Serge Hallyn <serge@hallyn.com>,
Varad Gautam <varad.gautam@suse.com>,
Vasily Averin <vvs@virtuozzo.com>,
kernel test robot <lkp@intel.com>
Subject: [PATCH v4 1/2] ipc: Store mqueue sysctls in the ipc namespace
Date: Mon, 14 Feb 2022 19:18:14 +0100 [thread overview]
Message-ID: <b0ccbb2489119f1f20c737cf1930c3a9c4e4243a.1644862280.git.legion@kernel.org> (raw)
In-Reply-To: <cover.1644862280.git.legion@kernel.org>
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>
---
include/linux/ipc_namespace.h | 16 +++--
ipc/mq_sysctl.c | 121 ++++++++++++++++++----------------
ipc/mqueue.c | 10 ++-
ipc/namespace.c | 6 ++
4 files changed, 88 insertions(+), 65 deletions(-)
diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index b75395ec8d52..fa787d97d60a 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -10,6 +10,7 @@
#include <linux/ns_common.h>
#include <linux/refcount.h>
#include <linux/rhashtable-types.h>
+#include <linux/sysctl.h>
struct user_namespace;
@@ -63,6 +64,9 @@ struct ipc_namespace {
unsigned int mq_msg_default;
unsigned int mq_msgsize_default;
+ struct ctl_table_set mq_set;
+ struct ctl_table_header *mq_sysctls;
+
/* user_ns which owns the ipc ns */
struct user_namespace *user_ns;
struct ucounts *ucounts;
@@ -169,14 +173,18 @@ static inline void put_ipc_ns(struct ipc_namespace *ns)
#ifdef CONFIG_POSIX_MQUEUE_SYSCTL
-struct ctl_table_header;
-extern struct ctl_table_header *mq_register_sysctl_table(void);
+void retire_mq_sysctls(struct ipc_namespace *ns);
+bool setup_mq_sysctls(struct ipc_namespace *ns);
#else /* CONFIG_POSIX_MQUEUE_SYSCTL */
-static inline struct ctl_table_header *mq_register_sysctl_table(void)
+static inline void retire_mq_sysctls(struct ipc_namespace *ns)
{
- return NULL;
+}
+
+static inline bool setup_mq_sysctls(struct ipc_namespace *ns)
+{
+ return true;
}
#endif /* CONFIG_POSIX_MQUEUE_SYSCTL */
diff --git a/ipc/mq_sysctl.c b/ipc/mq_sysctl.c
index 72a92a08c848..fbf6a8b93a26 100644
--- a/ipc/mq_sysctl.c
+++ b/ipc/mq_sysctl.c
@@ -9,39 +9,9 @@
#include <linux/ipc_namespace.h>
#include <linux/sysctl.h>
-#ifdef CONFIG_PROC_SYSCTL
-static void *get_mq(struct ctl_table *table)
-{
- char *which = table->data;
- struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
- which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns;
- return which;
-}
-
-static int proc_mq_dointvec(struct ctl_table *table, int write,
- void *buffer, size_t *lenp, loff_t *ppos)
-{
- struct ctl_table mq_table;
- memcpy(&mq_table, table, sizeof(mq_table));
- mq_table.data = get_mq(table);
-
- return proc_dointvec(&mq_table, write, buffer, lenp, ppos);
-}
-
-static int proc_mq_dointvec_minmax(struct ctl_table *table, int write,
- void *buffer, size_t *lenp, loff_t *ppos)
-{
- struct ctl_table mq_table;
- memcpy(&mq_table, table, sizeof(mq_table));
- mq_table.data = get_mq(table);
-
- return proc_dointvec_minmax(&mq_table, write, buffer,
- lenp, ppos);
-}
-#else
-#define proc_mq_dointvec NULL
-#define proc_mq_dointvec_minmax NULL
-#endif
+#include <linux/stat.h>
+#include <linux/capability.h>
+#include <linux/slab.h>
static int msg_max_limit_min = MIN_MSGMAX;
static int msg_max_limit_max = HARD_MSGMAX;
@@ -55,14 +25,14 @@ static struct ctl_table mq_sysctls[] = {
.data = &init_ipc_ns.mq_queues_max,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_mq_dointvec,
+ .proc_handler = proc_dointvec,
},
{
.procname = "msg_max",
.data = &init_ipc_ns.mq_msg_max,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_mq_dointvec_minmax,
+ .proc_handler = proc_dointvec_minmax,
.extra1 = &msg_max_limit_min,
.extra2 = &msg_max_limit_max,
},
@@ -71,7 +41,7 @@ static struct ctl_table mq_sysctls[] = {
.data = &init_ipc_ns.mq_msgsize_max,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_mq_dointvec_minmax,
+ .proc_handler = proc_dointvec_minmax,
.extra1 = &msg_maxsize_limit_min,
.extra2 = &msg_maxsize_limit_max,
},
@@ -80,7 +50,7 @@ static struct ctl_table mq_sysctls[] = {
.data = &init_ipc_ns.mq_msg_default,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_mq_dointvec_minmax,
+ .proc_handler = proc_dointvec_minmax,
.extra1 = &msg_max_limit_min,
.extra2 = &msg_max_limit_max,
},
@@ -89,32 +59,73 @@ static struct ctl_table mq_sysctls[] = {
.data = &init_ipc_ns.mq_msgsize_default,
.maxlen = sizeof(int),
.mode = 0644,
- .proc_handler = proc_mq_dointvec_minmax,
+ .proc_handler = proc_dointvec_minmax,
.extra1 = &msg_maxsize_limit_min,
.extra2 = &msg_maxsize_limit_max,
},
{}
};
-static struct ctl_table mq_sysctl_dir[] = {
- {
- .procname = "mqueue",
- .mode = 0555,
- .child = mq_sysctls,
- },
- {}
-};
+static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
+{
+ return ¤t->nsproxy->ipc_ns->mq_set;
+}
-static struct ctl_table mq_sysctl_root[] = {
- {
- .procname = "fs",
- .mode = 0555,
- .child = mq_sysctl_dir,
- },
- {}
+static int set_is_seen(struct ctl_table_set *set)
+{
+ return ¤t->nsproxy->ipc_ns->mq_set == set;
+}
+
+static struct ctl_table_root set_root = {
+ .lookup = set_lookup,
};
-struct ctl_table_header *mq_register_sysctl_table(void)
+bool setup_mq_sysctls(struct ipc_namespace *ns)
{
- return register_sysctl_table(mq_sysctl_root);
+ struct ctl_table *tbl;
+
+ setup_sysctl_set(&ns->mq_set, &set_root, set_is_seen);
+
+ tbl = kmemdup(mq_sysctls, sizeof(mq_sysctls), GFP_KERNEL);
+ if (tbl) {
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(mq_sysctls); i++) {
+ if (tbl[i].data == &init_ipc_ns.mq_queues_max)
+ tbl[i].data = &ns->mq_queues_max;
+
+ else if (tbl[i].data == &init_ipc_ns.mq_msg_max)
+ tbl[i].data = &ns->mq_msg_max;
+
+ else if (tbl[i].data == &init_ipc_ns.mq_msgsize_max)
+ tbl[i].data = &ns->mq_msgsize_max;
+
+ else if (tbl[i].data == &init_ipc_ns.mq_msg_default)
+ tbl[i].data = &ns->mq_msg_default;
+
+ else if (tbl[i].data == &init_ipc_ns.mq_msgsize_default)
+ tbl[i].data = &ns->mq_msgsize_default;
+ else
+ tbl[i].data = NULL;
+ }
+
+ ns->mq_sysctls = __register_sysctl_table(&ns->mq_set, "fs/mqueue", tbl);
+ }
+ if (!ns->mq_sysctls) {
+ kfree(tbl);
+ retire_sysctl_set(&ns->mq_set);
+ return false;
+ }
+
+ return true;
+}
+
+void retire_mq_sysctls(struct ipc_namespace *ns)
+{
+ struct ctl_table *tbl;
+
+ tbl = ns->mq_sysctls->ctl_table_arg;
+ unregister_sysctl_table(ns->mq_sysctls);
+ retire_sysctl_set(&ns->mq_set);
+ kfree(tbl);
}
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 5becca9be867..1b4a3be71636 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -163,8 +163,6 @@ static void remove_notification(struct mqueue_inode_info *info);
static struct kmem_cache *mqueue_inode_cachep;
-static struct ctl_table_header *mq_sysctl_table;
-
static inline struct mqueue_inode_info *MQUEUE_I(struct inode *inode)
{
return container_of(inode, struct mqueue_inode_info, vfs_inode);
@@ -1713,8 +1711,10 @@ static int __init init_mqueue_fs(void)
if (mqueue_inode_cachep == NULL)
return -ENOMEM;
- /* ignore failures - they are not fatal */
- mq_sysctl_table = mq_register_sysctl_table();
+ if (!setup_mq_sysctls(&init_ipc_ns)) {
+ pr_warn("sysctl registration failed\n");
+ return -ENOMEM;
+ }
error = register_filesystem(&mqueue_fs_type);
if (error)
@@ -1731,8 +1731,6 @@ static int __init init_mqueue_fs(void)
out_filesystem:
unregister_filesystem(&mqueue_fs_type);
out_sysctl:
- if (mq_sysctl_table)
- unregister_sysctl_table(mq_sysctl_table);
kmem_cache_destroy(mqueue_inode_cachep);
return error;
}
diff --git a/ipc/namespace.c b/ipc/namespace.c
index ae83f0f2651b..f760243ca685 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -59,6 +59,10 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
if (err)
goto fail_put;
+ err = -ENOMEM;
+ if (!setup_mq_sysctls(ns))
+ goto fail_put;
+
sem_init_ns(ns);
msg_init_ns(ns);
shm_init_ns(ns);
@@ -125,6 +129,8 @@ static void free_ipc_ns(struct ipc_namespace *ns)
msg_exit_ns(ns);
shm_exit_ns(ns);
+ retire_mq_sysctls(ns);
+
dec_ipc_namespaces(ns->ucounts);
put_user_ns(ns->user_ns);
ns_free_inum(&ns->ns);
--
2.33.0
next prev parent reply other threads:[~2022-02-14 18:20 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-14 18:18 [PATCH v4 0/2] ipc: Store mq and ipc sysctls in the ipc namespace Alexey Gladkov
2022-02-14 18:18 ` Alexey Gladkov [this message]
2022-02-14 18:18 ` [PATCH v4 2/2] ipc: Store " Alexey Gladkov
2022-03-23 20:24 ` [GIT PULL] ipc: Bind to the ipc namespace at open time Eric W. Biederman
2022-03-24 18:12 ` Linus Torvalds
2022-03-24 21:48 ` Eric W. Biederman
2022-03-24 22:16 ` Linus Torvalds
2022-03-25 12:10 ` Alexey Gladkov
2022-04-22 12:53 ` [PATCH v1 0/4] ipc: Remove extra1 field abuse to pass ipc namespace Alexey Gladkov
2022-04-22 12:53 ` [PATCH v1 1/4] " Alexey Gladkov
2022-05-02 16:07 ` Eric W. Biederman
2022-04-22 12:53 ` [PATCH v1 2/4] ipc: Use proper " Alexey Gladkov
2022-05-02 16:09 ` Eric W. Biederman
2022-05-03 13:39 ` Alexey Gladkov
2022-05-03 13:39 ` [PATCH v2 1/4] ipc: Use the same namespace to modify and validate Alexey Gladkov
2022-05-03 13:39 ` [PATCH v2 2/4] ipc: Remove extra1 field abuse to pass ipc namespace Alexey Gladkov
2022-05-03 13:39 ` [PATCH v2 3/4] ipc: Check permissions for checkpoint_restart sysctls at open time Alexey Gladkov
2022-05-03 13:39 ` [PATCH v2 4/4] ipc: Remove extra braces Alexey Gladkov
2022-04-22 12:53 ` [PATCH v1 3/4] ipc: Check permissions for checkpoint_restart sysctls at open time Alexey Gladkov
2022-04-22 12:53 ` [PATCH v1 4/4] ipc: Remove extra braces Alexey Gladkov
2022-04-22 20:44 ` [PATCH v1 0/4] ipc: Remove extra1 field abuse to pass ipc namespace Linus Torvalds
2022-05-04 3:42 ` Philip Rhoades
2022-06-01 13:20 ` [RFC PATCH 0/4] API extension for handling sysctl Alexey Gladkov
2022-06-01 13:20 ` [RFC PATCH 1/4] sysctl: " Alexey Gladkov
2022-06-01 19:19 ` Matthew Wilcox
2022-06-01 19:23 ` Linus Torvalds
2022-06-01 19:25 ` Matthew Wilcox
2022-06-01 19:31 ` Linus Torvalds
2022-06-01 19:32 ` Alexey Gladkov
2022-06-01 13:20 ` [RFC PATCH 2/4] sysctl: ipc: Do not use dynamic memory Alexey Gladkov
2022-06-01 16:45 ` Linus Torvalds
2022-06-01 18:24 ` Alexey Gladkov
2022-06-01 18:34 ` Linus Torvalds
2022-06-01 19:05 ` Alexey Gladkov
2022-06-09 18:51 ` Luis Chamberlain
2022-06-01 13:20 ` [RFC PATCH 3/4] sysctl: userns: " Alexey Gladkov
2022-06-01 13:20 ` [RFC PATCH 4/4] sysctl: mqueue: " Alexey Gladkov
2022-06-09 16:45 ` [RFC PATCH 0/4] API extension for handling sysctl Luis Chamberlain
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=b0ccbb2489119f1f20c737cf1930c3a9c4e4243a.1644862280.git.legion@kernel.org \
--to=legion@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=alexander.mikhalitsyn@virtuozzo.com \
--cc=christian.brauner@ubuntu.com \
--cc=containers@lists.linux.dev \
--cc=dbueso@suse.de \
--cc=dwalsh@redhat.com \
--cc=ebiederm@xmission.com \
--cc=ktkhai@virtuozzo.com \
--cc=linux-kernel@vger.kernel.org \
--cc=lkp@intel.com \
--cc=manfred@colorfullife.com \
--cc=serge@hallyn.com \
--cc=varad.gautam@suse.com \
--cc=vvs@virtuozzo.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).