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Commit 8b0fdf63 authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'work.mqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 

Pull mqueue/bpf vfs cleanups from Al Viro:
 "mqueue and bpf go through rather painful and similar contortions to
  create objects in their dentry trees. Provide a primitive for doing
  that without abusing ->mknod(), switch bpf and mqueue to it.

  Another mqueue-related thing that has ended up in that branch is
  on-demand creation of internal mount (based upon the work of Giuseppe
  Scrivano)"

* 'work.mqueue' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  mqueue: switch to on-demand creation of internal mount
  tidy do_mq_open() up a bit
  mqueue: clean prepare_open() up
  do_mq_open(): move all work prior to dentry_open() into a helper
  mqueue: fold mq_attr_ok() into mqueue_get_inode()
  move dentry_open() calls up into do_mq_open()
  mqueue: switch to vfs_mkobj(), quit abusing ->d_fsdata
  bpf_obj_do_pin(): switch to vfs_mkobj(), quit abusing ->mknod()
  new primitive: vfs_mkobj()
parents 168fe32a 36735a6a

fs/namei.c

+21 −0
Original line number Diff line number Diff line
@@ -2895,6 +2895,27 @@ int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, 
}

EXPORT_SYMBOL(vfs_create);



int vfs_mkobj(struct dentry *dentry, umode_t mode,

		int (*f)(struct dentry *, umode_t, void *),

		void *arg)

{

	struct inode *dir = dentry->d_parent->d_inode;

	int error = may_create(dir, dentry);

	if (error)

		return error;



	mode &= S_IALLUGO;

	mode |= S_IFREG;

	error = security_inode_create(dir, dentry, mode);

	if (error)

		return error;

	error = f(dentry, mode, arg);

	if (!error)

		fsnotify_create(dir, dentry);

	return error;

}

EXPORT_SYMBOL(vfs_mkobj);



bool may_open_dev(const struct path *path)

{

	return !(path->mnt->mnt_flags & MNT_NODEV) &&

include/linux/fs.h

+4 −0
Original line number Diff line number Diff line
@@ -1608,6 +1608,10 @@ extern int vfs_whiteout(struct inode *, struct dentry *); 
extern struct dentry *vfs_tmpfile(struct dentry *dentry, umode_t mode,

				  int open_flag);



int vfs_mkobj(struct dentry *, umode_t,

		int (*f)(struct dentry *, umode_t, void *),

		void *);



/*

 * VFS file helper functions.

 */

ipc/mqueue.c

+111 −130
Original line number Diff line number Diff line
@@ -270,13 +270,30 @@ static struct inode *mqueue_get_inode(struct super_block *sb, 
		 * that means the min(mq_maxmsg, max_priorities) * struct

		 * posix_msg_tree_node.

		 */



		ret = -EINVAL;

		if (info->attr.mq_maxmsg <= 0 || info->attr.mq_msgsize <= 0)

			goto out_inode;

		if (capable(CAP_SYS_RESOURCE)) {

			if (info->attr.mq_maxmsg > HARD_MSGMAX ||

			    info->attr.mq_msgsize > HARD_MSGSIZEMAX)

				goto out_inode;

		} else {

			if (info->attr.mq_maxmsg > ipc_ns->mq_msg_max ||

					info->attr.mq_msgsize > ipc_ns->mq_msgsize_max)

				goto out_inode;

		}

		ret = -EOVERFLOW;

		/* check for overflow */

		if (info->attr.mq_msgsize > ULONG_MAX/info->attr.mq_maxmsg)

			goto out_inode;

		mq_treesize = info->attr.mq_maxmsg * sizeof(struct msg_msg) +

			min_t(unsigned int, info->attr.mq_maxmsg, MQ_PRIO_MAX) *

			sizeof(struct posix_msg_tree_node);



		mq_bytes = mq_treesize + (info->attr.mq_maxmsg *

					  info->attr.mq_msgsize);



		mq_bytes = info->attr.mq_maxmsg * info->attr.mq_msgsize;

		if (mq_bytes + mq_treesize < mq_bytes)

			goto out_inode;

		mq_bytes += mq_treesize;

		spin_lock(&mq_lock);

		if (u->mq_bytes + mq_bytes < u->mq_bytes ||

		    u->mq_bytes + mq_bytes > rlimit(RLIMIT_MSGQUEUE)) {
@@ -308,8 +325,9 @@ static struct inode *mqueue_get_inode(struct super_block *sb, 
static int mqueue_fill_super(struct super_block *sb, void *data, int silent)

{

	struct inode *inode;

	struct ipc_namespace *ns = sb->s_fs_info;

	struct ipc_namespace *ns = data;



	sb->s_fs_info = ns;

	sb->s_iflags |= SB_I_NOEXEC | SB_I_NODEV;

	sb->s_blocksize = PAGE_SIZE;

	sb->s_blocksize_bits = PAGE_SHIFT;
@@ -326,18 +344,44 @@ static int mqueue_fill_super(struct super_block *sb, void *data, int silent) 
	return 0;

}



static struct file_system_type mqueue_fs_type;

/*

 * Return value is pinned only by reference in ->mq_mnt; it will

 * live until ipcns dies.  Caller does not need to drop it.

 */

static struct vfsmount *mq_internal_mount(void)

{

	struct ipc_namespace *ns = current->nsproxy->ipc_ns;

	struct vfsmount *m = ns->mq_mnt;

	if (m)

		return m;

	m = kern_mount_data(&mqueue_fs_type, ns);

	spin_lock(&mq_lock);

	if (unlikely(ns->mq_mnt)) {

		spin_unlock(&mq_lock);

		if (!IS_ERR(m))

			kern_unmount(m);

		return ns->mq_mnt;

	}

	if (!IS_ERR(m))

		ns->mq_mnt = m;

	spin_unlock(&mq_lock);

	return m;

}



static struct dentry *mqueue_mount(struct file_system_type *fs_type,

			 int flags, const char *dev_name,

			 void *data)

{

	struct ipc_namespace *ns;

	if (flags & SB_KERNMOUNT) {

		ns = data;

		data = NULL;

	} else {

		ns = current->nsproxy->ipc_ns;

	}

	return mount_ns(fs_type, flags, data, ns, ns->user_ns, mqueue_fill_super);

	struct vfsmount *m;

	if (flags & SB_KERNMOUNT)

		return mount_nodev(fs_type, flags, data, mqueue_fill_super);

	m = mq_internal_mount();

	if (IS_ERR(m))

		return ERR_CAST(m);

	atomic_inc(&m->mnt_sb->s_active);

	down_write(&m->mnt_sb->s_umount);

	return dget(m->mnt_root);

}



static void init_once(void *foo)
@@ -416,11 +460,11 @@ static void mqueue_evict_inode(struct inode *inode) 
		put_ipc_ns(ipc_ns);

}



static int mqueue_create(struct inode *dir, struct dentry *dentry,

				umode_t mode, bool excl)

static int mqueue_create_attr(struct dentry *dentry, umode_t mode, void *arg)

{

	struct inode *dir = dentry->d_parent->d_inode;

	struct inode *inode;

	struct mq_attr *attr = dentry->d_fsdata;

	struct mq_attr *attr = arg;

	int error;

	struct ipc_namespace *ipc_ns;
@@ -461,6 +505,12 @@ static int mqueue_create(struct inode *dir, struct dentry *dentry, 
	return error;

}



static int mqueue_create(struct inode *dir, struct dentry *dentry,

				umode_t mode, bool excl)

{

	return mqueue_create_attr(dentry, mode, NULL);

}



static int mqueue_unlink(struct inode *dir, struct dentry *dentry)

{

	struct inode *inode = d_inode(dentry);
@@ -691,96 +741,46 @@ static void remove_notification(struct mqueue_inode_info *info) 
	info->notify_user_ns = NULL;

}



static int mq_attr_ok(struct ipc_namespace *ipc_ns, struct mq_attr *attr)

{

	int mq_treesize;

	unsigned long total_size;



	if (attr->mq_maxmsg <= 0 || attr->mq_msgsize <= 0)

		return -EINVAL;

	if (capable(CAP_SYS_RESOURCE)) {

		if (attr->mq_maxmsg > HARD_MSGMAX ||

		    attr->mq_msgsize > HARD_MSGSIZEMAX)

			return -EINVAL;

	} else {

		if (attr->mq_maxmsg > ipc_ns->mq_msg_max ||

				attr->mq_msgsize > ipc_ns->mq_msgsize_max)

			return -EINVAL;

	}

	/* check for overflow */

	if (attr->mq_msgsize > ULONG_MAX/attr->mq_maxmsg)

		return -EOVERFLOW;

	mq_treesize = attr->mq_maxmsg * sizeof(struct msg_msg) +

		min_t(unsigned int, attr->mq_maxmsg, MQ_PRIO_MAX) *

		sizeof(struct posix_msg_tree_node);

	total_size = attr->mq_maxmsg * attr->mq_msgsize;

	if (total_size + mq_treesize < total_size)

		return -EOVERFLOW;

	return 0;

}



/*

 * Invoked when creating a new queue via sys_mq_open

 */

static struct file *do_create(struct ipc_namespace *ipc_ns, struct inode *dir,

			struct path *path, int oflag, umode_t mode,

static int prepare_open(struct dentry *dentry, int oflag, int ro,

			umode_t mode, struct filename *name,

			struct mq_attr *attr)

{

	const struct cred *cred = current_cred();

	int ret;



	if (attr) {

		ret = mq_attr_ok(ipc_ns, attr);

		if (ret)

			return ERR_PTR(ret);

		/* store for use during create */

		path->dentry->d_fsdata = attr;

	} else {

		struct mq_attr def_attr;



		def_attr.mq_maxmsg = min(ipc_ns->mq_msg_max,

					 ipc_ns->mq_msg_default);

		def_attr.mq_msgsize = min(ipc_ns->mq_msgsize_max,

					  ipc_ns->mq_msgsize_default);

		ret = mq_attr_ok(ipc_ns, &def_attr);

		if (ret)

			return ERR_PTR(ret);

	}



	mode &= ~current_umask();

	ret = vfs_create(dir, path->dentry, mode, true);

	path->dentry->d_fsdata = NULL;

	if (ret)

		return ERR_PTR(ret);

	return dentry_open(path, oflag, cred);

}



/* Opens existing queue */

static struct file *do_open(struct path *path, int oflag)

{

	static const int oflag2acc[O_ACCMODE] = { MAY_READ, MAY_WRITE,

						  MAY_READ | MAY_WRITE };

	int acc;



	if (d_really_is_negative(dentry)) {

		if (!(oflag & O_CREAT))

			return -ENOENT;

		if (ro)

			return ro;

		audit_inode_parent_hidden(name, dentry->d_parent);

		return vfs_mkobj(dentry, mode & ~current_umask(),

				  mqueue_create_attr, attr);

	}

	/* it already existed */

	audit_inode(name, dentry, 0);

	if ((oflag & (O_CREAT|O_EXCL)) == (O_CREAT|O_EXCL))

		return -EEXIST;

	if ((oflag & O_ACCMODE) == (O_RDWR | O_WRONLY))

		return ERR_PTR(-EINVAL);

		return -EINVAL;

	acc = oflag2acc[oflag & O_ACCMODE];

	if (inode_permission(d_inode(path->dentry), acc))

		return ERR_PTR(-EACCES);

	return dentry_open(path, oflag, current_cred());

	return inode_permission(d_inode(dentry), acc);

}



static int do_mq_open(const char __user *u_name, int oflag, umode_t mode,

		      struct mq_attr *attr)

{

	struct path path;

	struct file *filp;

	struct vfsmount *mnt = mq_internal_mount();

	struct dentry *root;

	struct filename *name;

	struct path path;

	int fd, error;

	struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;

	struct vfsmount *mnt = ipc_ns->mq_mnt;

	struct dentry *root = mnt->mnt_root;

	int ro;



	if (IS_ERR(mnt))

		return PTR_ERR(mnt);



	audit_mq_open(oflag, mode, attr);



	if (IS_ERR(name = getname(u_name)))
@@ -791,7 +791,7 @@ static int do_mq_open(const char __user *u_name, int oflag, umode_t mode, 
		goto out_putname;



	ro = mnt_want_write(mnt);	/* we'll drop it in any case */

	error = 0;

	root = mnt->mnt_root;

	inode_lock(d_inode(root));

	path.dentry = lookup_one_len(name->name, root, strlen(name->name));

	if (IS_ERR(path.dentry)) {
@@ -799,38 +799,14 @@ static int do_mq_open(const char __user *u_name, int oflag, umode_t mode, 
		goto out_putfd;

	}

	path.mnt = mntget(mnt);



	if (oflag & O_CREAT) {

		if (d_really_is_positive(path.dentry)) {	/* entry already exists */

			audit_inode(name, path.dentry, 0);

			if (oflag & O_EXCL) {

				error = -EEXIST;

				goto out;

			}

			filp = do_open(&path, oflag);

		} else {

			if (ro) {

				error = ro;

				goto out;

			}

			audit_inode_parent_hidden(name, root);

			filp = do_create(ipc_ns, d_inode(root), &path,

					 oflag, mode, attr);

		}

	} else {

		if (d_really_is_negative(path.dentry)) {

			error = -ENOENT;

			goto out;

		}

		audit_inode(name, path.dentry, 0);

		filp = do_open(&path, oflag);

	}



	if (!IS_ERR(filp))

		fd_install(fd, filp);

	error = prepare_open(path.dentry, oflag, ro, mode, name, attr);

	if (!error) {

		struct file *file = dentry_open(&path, oflag, current_cred());

		if (!IS_ERR(file))

			fd_install(fd, file);

		else

		error = PTR_ERR(filp);

out:

			error = PTR_ERR(file);

	}

	path_put(&path);

out_putfd:

	if (error) {
@@ -864,6 +840,9 @@ SYSCALL_DEFINE1(mq_unlink, const char __user *, u_name) 
	struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;

	struct vfsmount *mnt = ipc_ns->mq_mnt;



	if (!mnt)

		return -ENOENT;



	name = getname(u_name);

	if (IS_ERR(name))

		return PTR_ERR(name);
@@ -1590,28 +1569,26 @@ int mq_init_ns(struct ipc_namespace *ns) 
	ns->mq_msgsize_max   = DFLT_MSGSIZEMAX;

	ns->mq_msg_default   = DFLT_MSG;

	ns->mq_msgsize_default  = DFLT_MSGSIZE;



	ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);

	if (IS_ERR(ns->mq_mnt)) {

		int err = PTR_ERR(ns->mq_mnt);

	ns->mq_mnt = NULL;

		return err;

	}



	return 0;

}



void mq_clear_sbinfo(struct ipc_namespace *ns)

{

	if (ns->mq_mnt)

		ns->mq_mnt->mnt_sb->s_fs_info = NULL;

}



void mq_put_mnt(struct ipc_namespace *ns)

{

	if (ns->mq_mnt)

		kern_unmount(ns->mq_mnt);

}



static int __init init_mqueue_fs(void)

{

	struct vfsmount *m;

	int error;



	mqueue_inode_cachep = kmem_cache_create("mqueue_inode_cache",
@@ -1633,6 +1610,10 @@ static int __init init_mqueue_fs(void) 
	if (error)

		goto out_filesystem;



	m = kern_mount_data(&mqueue_fs_type, &init_ipc_ns);

	if (IS_ERR(m))

		goto out_filesystem;

	init_ipc_ns.mq_mnt = m;

	return 0;



out_filesystem:

kernel/bpf/inode.c

+22 −28
Original line number Diff line number Diff line
@@ -150,39 +150,29 @@ static int bpf_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 
	return 0;

}



static int bpf_mkobj_ops(struct inode *dir, struct dentry *dentry,

			 umode_t mode, const struct inode_operations *iops)

static int bpf_mkobj_ops(struct dentry *dentry, umode_t mode, void *raw,

			 const struct inode_operations *iops)

{

	struct inode *inode;



	inode = bpf_get_inode(dir->i_sb, dir, mode | S_IFREG);

	struct inode *dir = dentry->d_parent->d_inode;

	struct inode *inode = bpf_get_inode(dir->i_sb, dir, mode);

	if (IS_ERR(inode))

		return PTR_ERR(inode);



	inode->i_op = iops;

	inode->i_private = dentry->d_fsdata;

	inode->i_private = raw;



	bpf_dentry_finalize(dentry, inode, dir);

	return 0;

}



static int bpf_mkobj(struct inode *dir, struct dentry *dentry, umode_t mode,

		     dev_t devt)

static int bpf_mkprog(struct dentry *dentry, umode_t mode, void *arg)

{

	enum bpf_type type = MINOR(devt);



	if (MAJOR(devt) != UNNAMED_MAJOR || !S_ISREG(mode) ||

	    dentry->d_fsdata == NULL)

		return -EPERM;



	switch (type) {

	case BPF_TYPE_PROG:

		return bpf_mkobj_ops(dir, dentry, mode, &bpf_prog_iops);

	case BPF_TYPE_MAP:

		return bpf_mkobj_ops(dir, dentry, mode, &bpf_map_iops);

	default:

		return -EPERM;

	return bpf_mkobj_ops(dentry, mode, arg, &bpf_prog_iops);

}



static int bpf_mkmap(struct dentry *dentry, umode_t mode, void *arg)

{

	return bpf_mkobj_ops(dentry, mode, arg, &bpf_map_iops);

}



static struct dentry *
@@ -218,7 +208,6 @@ static int bpf_symlink(struct inode *dir, struct dentry *dentry, 


static const struct inode_operations bpf_dir_iops = {

	.lookup		= bpf_lookup,

	.mknod		= bpf_mkobj,

	.mkdir		= bpf_mkdir,

	.symlink	= bpf_symlink,

	.rmdir		= simple_rmdir,
@@ -234,7 +223,6 @@ static int bpf_obj_do_pin(const struct filename *pathname, void *raw, 
	struct inode *dir;

	struct path path;

	umode_t mode;

	dev_t devt;

	int ret;



	dentry = kern_path_create(AT_FDCWD, pathname->name, &path, 0);
@@ -242,9 +230,8 @@ static int bpf_obj_do_pin(const struct filename *pathname, void *raw, 
		return PTR_ERR(dentry);



	mode = S_IFREG | ((S_IRUSR | S_IWUSR) & ~current_umask());

	devt = MKDEV(UNNAMED_MAJOR, type);



	ret = security_path_mknod(&path, dentry, mode, devt);

	ret = security_path_mknod(&path, dentry, mode, 0);

	if (ret)

		goto out;
@@ -254,9 +241,16 @@ static int bpf_obj_do_pin(const struct filename *pathname, void *raw, 
		goto out;

	}



	dentry->d_fsdata = raw;

	ret = vfs_mknod(dir, dentry, mode, devt);

	dentry->d_fsdata = NULL;

	switch (type) {

	case BPF_TYPE_PROG:

		ret = vfs_mkobj(dentry, mode, bpf_mkprog, raw);

		break;

	case BPF_TYPE_MAP:

		ret = vfs_mkobj(dentry, mode, bpf_mkmap, raw);

		break;

	default:

		ret = -EPERM;

	}

out:

	done_path_create(&path, dentry);

	return ret;