Cedric,
how safe does it intersect with netlinks from network namespace?
I see mqueues can send netlink messages, have you checked how safe it is?
Thanks,
Kirill
Cedric Le Goater wrote:
> From: Cedric Le Goater <[EMAIL PROTECTED]>
>
> This patch adds a struct mq_namespace holding the common attributes
> of the mqueue namespace.
>
> The current code is modified to use the default mqueue namespace
> object 'init_mq_ns' and to prepare the ground for futur dynamic
> objects.
>
> Todo:
> - use CONFIG_NAMESPACE when next -mm is released
>
> Signed-off-by: Cedric Le Goater <[EMAIL PROTECTED]>
> ---
> include/linux/mq_namespace.h | 60 +++++++++++++++++++++++
> ipc/mqueue.c | 111
> +++++++++++++++++++++++++++----------------
> 2 files changed, 130 insertions(+), 41 deletions(-)
>
> Index: 2.6.23-rc8-mm2/include/linux/mq_namespace.h
> ===================================================================
> --- /dev/null
> +++ 2.6.23-rc8-mm2/include/linux/mq_namespace.h
> @@ -0,0 +1,60 @@
> +#ifndef _LINUX_MQ_NAMESPACE_H
> +#define _LINUX_MQ_NAMESPACE_H
> +
> +#include <linux/kref.h>
> +
> +struct vfsmount;
> +
> +struct mq_namespace {
> + struct kref kref;
> + struct vfsmount *mnt;
> +
> + unsigned int queues_count;
> + unsigned int queues_max;
> + unsigned int msg_max;
> + unsigned int msgsize_max;
> +};
> +
> +extern struct mq_namespace init_mq_ns;
> +
> +#ifdef CONFIG_POSIX_MQUEUE
> +
> +#define INIT_MQ_NS(ns) .ns = &init_mq_ns,
> +
> +static inline struct mq_namespace *get_mq_ns(struct mq_namespace *ns)
> +{
> + if (ns)
> + kref_get(&ns->kref);
> + return ns;
> +}
> +
> +extern struct mq_namespace *copy_mq_ns(unsigned long flags,
> + struct mq_namespace *old_ns);
> +extern void free_mq_ns(struct kref *kref);
> +
> +static inline void put_mq_ns(struct mq_namespace *ns)
> +{
> + if (ns)
> + kref_put(&ns->kref, free_mq_ns);
> +}
> +
> +#else
> +
> +#define INIT_MQ_NS(ns)
> +
> +static inline struct mq_namespace *get_mq_ns(struct mq_namespace *ns)
> +{
> + return ns;
> +}
> +
> +static inline struct mq_namespace *copy_mq_ns(unsigned long flags,
> + struct mq_namespace *old_ns)
> +{
> + return old_ns;
> +}
> +
> +static inline void put_mq_ns(struct mq_namespace *ns) { }
> +
> +#endif /* CONFIG_POSIX_MQUEUE */
> +
> +#endif /* _LINUX_MQ_H */
> Index: 2.6.23-rc8-mm2/ipc/mqueue.c
> ===================================================================
> --- 2.6.23-rc8-mm2.orig/ipc/mqueue.c
> +++ 2.6.23-rc8-mm2/ipc/mqueue.c
> @@ -31,6 +31,7 @@
> #include <linux/mutex.h>
> #include <linux/nsproxy.h>
> #include <linux/pid.h>
> +#include <linux/mq_namespace.h>
>
> #include <net/sock.h>
> #include "util.h"
> @@ -87,12 +88,18 @@ static void remove_notification(struct m
>
> static spinlock_t mq_lock;
> static struct kmem_cache *mqueue_inode_cachep;
> -static struct vfsmount *mqueue_mnt;
>
> -static unsigned int queues_count;
> -static unsigned int queues_max = DFLT_QUEUESMAX;
> -static unsigned int msg_max = DFLT_MSGMAX;
> -static unsigned int msgsize_max = DFLT_MSGSIZEMAX;
> +struct mq_namespace init_mq_ns = {
> + .kref = {
> + .refcount = ATOMIC_INIT(2),
> + },
> + .mnt = NULL,
> + .queues_count = 0,
> + .queues_max = DFLT_QUEUESMAX,
> + .msg_max = DFLT_MSGMAX,
> + .msgsize_max = DFLT_MSGSIZEMAX,
> +};
> +
>
> static struct ctl_table_header * mq_sysctl_table;
>
> @@ -101,6 +108,21 @@ static inline struct mqueue_inode_info *
> return container_of(inode, struct mqueue_inode_info, vfs_inode);
> }
>
> +struct mq_namespace *copy_mq_ns(unsigned long flags,
> + struct mq_namespace *old_ns)
> +{
> + BUG_ON(!old_ns);
> + return get_mq_ns(old_ns);
> +}
> +
> +void free_mq_ns(struct kref *kref)
> +{
> + struct mq_namespace *mq_ns;
> +
> + mq_ns = container_of(kref, struct mq_namespace, kref);
> + kfree(mq_ns);
> +}
> +
> static struct inode *mqueue_get_inode(struct super_block *sb, int mode,
> struct mq_attr *attr)
> {
> @@ -235,6 +257,7 @@ static void mqueue_delete_inode(struct i
> struct user_struct *user;
> unsigned long mq_bytes;
> int i;
> + struct mq_namespace *mq_ns = &init_mq_ns;
>
> if (S_ISDIR(inode->i_mode)) {
> clear_inode(inode);
> @@ -255,7 +278,7 @@ static void mqueue_delete_inode(struct i
> if (user) {
> spin_lock(&mq_lock);
> user->mq_bytes -= mq_bytes;
> - queues_count--;
> + mq_ns->queues_count--;
> spin_unlock(&mq_lock);
> free_uid(user);
> }
> @@ -267,20 +290,22 @@ static int mqueue_create(struct inode *d
> struct inode *inode;
> struct mq_attr *attr = dentry->d_fsdata;
> int error;
> + struct mq_namespace *mq_ns = &init_mq_ns;
>
> spin_lock(&mq_lock);
> - if (queues_count >= queues_max && !capable(CAP_SYS_RESOURCE)) {
> + if (mq_ns->queues_count >= mq_ns->queues_max &&
> + !capable(CAP_SYS_RESOURCE)) {
> error = -ENOSPC;
> goto out_lock;
> }
> - queues_count++;
> + mq_ns->queues_count++;
> spin_unlock(&mq_lock);
>
> inode = mqueue_get_inode(dir->i_sb, mode, attr);
> if (!inode) {
> error = -ENOMEM;
> spin_lock(&mq_lock);
> - queues_count--;
> + mq_ns->queues_count--;
> goto out_lock;
> }
>
> @@ -571,7 +596,7 @@ static void remove_notification(struct m
> info->notify_owner = NULL;
> }
>
> -static int mq_attr_ok(struct mq_attr *attr)
> +static int mq_attr_ok(struct mq_namespace *mq_ns, struct mq_attr *attr)
> {
> if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)
> return 0;
> @@ -579,8 +604,8 @@ static int mq_attr_ok(struct mq_attr *at
> if (attr->mq_maxmsg > HARD_MSGMAX)
> return 0;
> } else {
> - if (attr->mq_maxmsg > msg_max ||
> - attr->mq_msgsize > msgsize_max)
> + if (attr->mq_maxmsg > mq_ns->msg_max ||
> + attr->mq_msgsize > mq_ns->msgsize_max)
> return 0;
> }
> /* check for overflow */
> @@ -596,8 +621,9 @@ static int mq_attr_ok(struct mq_attr *at
> /*
> * Invoked when creating a new queue via sys_mq_open
> */
> -static struct file *do_create(struct dentry *dir, struct dentry *dentry,
> - int oflag, mode_t mode, struct mq_attr __user *u_attr)
> +static struct file *do_create(struct mq_namespace *mq_ns, struct dentry *dir,
> + struct dentry *dentry, int oflag, mode_t mode,
> + struct mq_attr __user *u_attr)
> {
> struct mq_attr attr;
> int ret;
> @@ -607,7 +633,7 @@ static struct file *do_create(struct den
> if (copy_from_user(&attr, u_attr, sizeof(attr)))
> goto out;
> ret = -EINVAL;
> - if (!mq_attr_ok(&attr))
> + if (!mq_attr_ok(mq_ns, &attr))
> goto out;
> /* store for use during create */
> dentry->d_fsdata = &attr;
> @@ -619,33 +645,34 @@ static struct file *do_create(struct den
> if (ret)
> goto out;
>
> - return dentry_open(dentry, mqueue_mnt, oflag);
> + return dentry_open(dentry, mq_ns->mnt, oflag);
>
> out:
> dput(dentry);
> - mntput(mqueue_mnt);
> + mntput(mq_ns->mnt);
> return ERR_PTR(ret);
> }
>
> /* Opens existing queue */
> -static struct file *do_open(struct dentry *dentry, int oflag)
> +static struct file *do_open(struct mq_namespace *mq_ns, struct dentry
> *dentry,
> + int oflag)
> {
> static int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,
> MAY_READ | MAY_WRITE };
>
> if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY)) {
> dput(dentry);
> - mntput(mqueue_mnt);
> + mntput(mq_ns->mnt);
> return ERR_PTR(-EINVAL);
> }
>
> if (permission(dentry->d_inode, oflag2acc[oflag & O_ACCMODE], NULL)) {
> dput(dentry);
> - mntput(mqueue_mnt);
> + mntput(mq_ns->mnt);
> return ERR_PTR(-EACCES);
> }
>
> - return dentry_open(dentry, mqueue_mnt, oflag);
> + return dentry_open(dentry, mq_ns->mnt, oflag);
> }
>
> asmlinkage long sys_mq_open(const char __user *u_name, int oflag, mode_t
> mode,
> @@ -655,6 +682,7 @@ asmlinkage long sys_mq_open(const char _
> struct file *filp;
> char *name;
> int fd, error;
> + struct mq_namespace *mq_ns = &init_mq_ns;
>
> error = audit_mq_open(oflag, mode, u_attr);
> if (error != 0)
> @@ -667,13 +695,13 @@ asmlinkage long sys_mq_open(const char _
> if (fd < 0)
> goto out_putname;
>
> - mutex_lock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
> - dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
> + mutex_lock(&mq_ns->mnt->mnt_root->d_inode->i_mutex);
> + dentry = lookup_one_len(name, mq_ns->mnt->mnt_root, strlen(name));
> if (IS_ERR(dentry)) {
> error = PTR_ERR(dentry);
> goto out_err;
> }
> - mntget(mqueue_mnt);
> + mntget(mq_ns->mnt);
>
> if (oflag & O_CREAT) {
> if (dentry->d_inode) { /* entry already exists */
> @@ -681,12 +709,12 @@ asmlinkage long sys_mq_open(const char _
> error = -EEXIST;
> if (oflag & O_EXCL)
> goto out;
> - filp = do_open(dentry, oflag);
> + filp = do_open(mq_ns, dentry, oflag);
> } else {
> - error = mnt_want_write(mqueue_mnt);
> + error = mnt_want_write(mq_ns->mnt);
> if (error)
> goto out;
> - filp = do_create(mqueue_mnt->mnt_root, dentry,
> + filp = do_create(mq_ns, mq_ns->mnt->mnt_root, dentry,
> oflag, mode, u_attr);
> }
> } else {
> @@ -694,7 +722,7 @@ asmlinkage long sys_mq_open(const char _
> if (!dentry->d_inode)
> goto out;
> audit_inode(name, dentry);
> - filp = do_open(dentry, oflag);
> + filp = do_open(mq_ns, dentry, oflag);
> }
>
> if (IS_ERR(filp)) {
> @@ -708,13 +736,13 @@ asmlinkage long sys_mq_open(const char _
>
> out:
> dput(dentry);
> - mntput(mqueue_mnt);
> + mntput(mq_ns->mnt);
> out_putfd:
> put_unused_fd(fd);
> out_err:
> fd = error;
> out_upsem:
> - mutex_unlock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
> + mutex_unlock(&mq_ns->mnt->mnt_root->d_inode->i_mutex);
> out_putname:
> putname(name);
> return fd;
> @@ -726,14 +754,15 @@ asmlinkage long sys_mq_unlink(const char
> char *name;
> struct dentry *dentry;
> struct inode *inode = NULL;
> + struct mq_namespace *mq_ns = &init_mq_ns;
>
> name = getname(u_name);
> if (IS_ERR(name))
> return PTR_ERR(name);
>
> - mutex_lock_nested(&mqueue_mnt->mnt_root->d_inode->i_mutex,
> + mutex_lock_nested(&mq_ns->mnt->mnt_root->d_inode->i_mutex,
> I_MUTEX_PARENT);
> - dentry = lookup_one_len(name, mqueue_mnt->mnt_root, strlen(name));
> + dentry = lookup_one_len(name, mq_ns->mnt->mnt_root, strlen(name));
> if (IS_ERR(dentry)) {
> err = PTR_ERR(dentry);
> goto out_unlock;
> @@ -747,16 +776,16 @@ asmlinkage long sys_mq_unlink(const char
> inode = dentry->d_inode;
> if (inode)
> atomic_inc(&inode->i_count);
> - err = mnt_want_write(mqueue_mnt);
> + err = mnt_want_write(mq_ns->mnt);
> if (err)
> goto out_err;
> err = vfs_unlink(dentry->d_parent->d_inode, dentry);
> - mnt_drop_write(mqueue_mnt);
> + mnt_drop_write(mq_ns->mnt);
> out_err:
> dput(dentry);
>
> out_unlock:
> - mutex_unlock(&mqueue_mnt->mnt_root->d_inode->i_mutex);
> + mutex_unlock(&mq_ns->mnt->mnt_root->d_inode->i_mutex);
> putname(name);
> if (inode)
> iput(inode);
> @@ -1201,14 +1230,14 @@ static int msg_maxsize_limit_max = INT_M
> static ctl_table mq_sysctls[] = {
> {
> .procname = "queues_max",
> - .data = &queues_max,
> + .data = &init_mq_ns.queues_max,
> .maxlen = sizeof(int),
> .mode = 0644,
> .proc_handler = &proc_dointvec,
> },
> {
> .procname = "msg_max",
> - .data = &msg_max,
> + .data = &init_mq_ns.msg_max,
> .maxlen = sizeof(int),
> .mode = 0644,
> .proc_handler = &proc_dointvec_minmax,
> @@ -1217,7 +1246,7 @@ static ctl_table mq_sysctls[] = {
> },
> {
> .procname = "msgsize_max",
> - .data = &msgsize_max,
> + .data = &init_mq_ns.msgsize_max,
> .maxlen = sizeof(int),
> .mode = 0644,
> .proc_handler = &proc_dointvec_minmax,
> @@ -1263,13 +1292,13 @@ static int __init init_mqueue_fs(void)
> if (error)
> goto out_sysctl;
>
> - if (IS_ERR(mqueue_mnt = kern_mount(&mqueue_fs_type))) {
> - error = PTR_ERR(mqueue_mnt);
> + init_mq_ns.mnt = kern_mount(&mqueue_fs_type);
> + if (IS_ERR(init_mq_ns.mnt)) {
> + error = PTR_ERR(init_mq_ns.mnt);
> goto out_filesystem;
> }
>
> /* internal initialization - not common for vfs */
> - queues_count = 0;
> spin_lock_init(&mq_lock);
>
> return 0;
>
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