1 files changed, 101 insertions, 186 deletions

diff --git a/fs/autofs4/dev-ioctl.c b/fs/autofs4/dev-ioctl.c
index 9e5ae8a4f5c..5b570b6efa2 100644
--- a/fs/autofs4/dev-ioctl.c
+++ b/fs/autofs4/dev-ioctl.c
@@ -19,10 +19,10 @@
 #include <linux/sched.h>
 #include <linux/compat.h>
 #include <linux/syscalls.h>
-#include <linux/smp_lock.h>
 #include <linux/magic.h>
 #include <linux/dcache.h>
 #include <linux/uaccess.h>
+#include <linux/slab.h>
 
 #include "autofs_i.h"
 
@@ -54,11 +54,10 @@ static int check_name(const char *name)
  * Check a string doesn't overrun the chunk of
  * memory we copied from user land.
  */
-static int invalid_str(char *str, void *end)
+static int invalid_str(char *str, size_t size)
 {
-	while ((void *) str <= end)
-		if (!*str++)
-			return 0;
+	if (memchr(str, 0, size))
+		return 0;
 	return -EINVAL;
 }
 
@@ -96,7 +95,7 @@ static int check_dev_ioctl_version(int cmd, struct autofs_dev_ioctl *param)
  */
 static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *in)
 {
-	struct autofs_dev_ioctl tmp, *ads;
+	struct autofs_dev_ioctl tmp;
 
 	if (copy_from_user(&tmp, in, sizeof(tmp)))
 		return ERR_PTR(-EFAULT);
@@ -104,16 +103,10 @@ static struct autofs_dev_ioctl *copy_dev_ioctl(struct autofs_dev_ioctl __user *i
 	if (tmp.size < sizeof(tmp))
 		return ERR_PTR(-EINVAL);
 
-	ads = kmalloc(tmp.size, GFP_KERNEL);
-	if (!ads)
-		return ERR_PTR(-ENOMEM);
+	if (tmp.size > (PATH_MAX + sizeof(tmp)))
+		return ERR_PTR(-ENAMETOOLONG);
 
-	if (copy_from_user(ads, in, tmp.size)) {
-		kfree(ads);
-		return ERR_PTR(-EFAULT);
-	}
-
-	return ads;
+	return memdup_user(in, tmp.size);
 }
 
 static inline void free_dev_ioctl(struct autofs_dev_ioctl *param)
@@ -138,8 +131,7 @@ static int validate_dev_ioctl(int cmd, struct autofs_dev_ioctl *param)
 	}
 
 	if (param->size > sizeof(*param)) {
-		err = invalid_str(param->path,
-				 (void *) ((size_t) param + param->size));
+		err = invalid_str(param->path, param->size - sizeof(*param));
 		if (err) {
 			AUTOFS_WARN(
 			  "path string terminator missing for cmd(0x%08x)",
@@ -170,7 +162,7 @@ static struct autofs_sb_info *autofs_dev_ioctl_sbi(struct file *f)
 	struct inode *inode;
 
 	if (f) {
-		inode = f->f_path.dentry->d_inode;
+		inode = file_inode(f);
 		sbi = autofs4_sbi(inode->i_sb);
 	}
 	return sbi;
@@ -194,129 +186,74 @@ static int autofs_dev_ioctl_protosubver(struct file *fp,
 	return 0;
 }
 
-/*
- * Walk down the mount stack looking for an autofs mount that
- * has the requested device number (aka. new_encode_dev(sb->s_dev).
- */
-static int autofs_dev_ioctl_find_super(struct nameidata *nd, dev_t devno)
+/* Find the topmost mount satisfying test() */
+static int find_autofs_mount(const char *pathname,
+			     struct path *res,
+			     int test(struct path *path, void *data),
+			     void *data)
 {
-	struct dentry *dentry;
-	struct inode *inode;
-	struct super_block *sb;
-	dev_t s_dev;
-	unsigned int err;
-
+	struct path path;
+	int err = kern_path_mountpoint(AT_FDCWD, pathname, &path, 0);
+	if (err)
+		return err;
 	err = -ENOENT;
-
-	/* Lookup the dentry name at the base of our mount point */
-	dentry = d_lookup(nd->path.dentry, &nd->last);
-	if (!dentry)
-		goto out;
-
-	dput(nd->path.dentry);
-	nd->path.dentry = dentry;
-
-	/* And follow the mount stack looking for our autofs mount */
-	while (follow_down(&nd->path.mnt, &nd->path.dentry)) {
-		inode = nd->path.dentry->d_inode;
-		if (!inode)
-			break;
-
-		sb = inode->i_sb;
-		s_dev = new_encode_dev(sb->s_dev);
-		if (devno == s_dev) {
-			if (sb->s_magic == AUTOFS_SUPER_MAGIC) {
+	while (path.dentry == path.mnt->mnt_root) {
+		if (path.dentry->d_sb->s_magic == AUTOFS_SUPER_MAGIC) {
+			if (test(&path, data)) {
+				path_get(&path);
+				*res = path;
 				err = 0;
 				break;
 			}
 		}
+		if (!follow_up(&path))
+			break;
 	}
-out:
+	path_put(&path);
 	return err;
 }
 
-/*
- * Walk down the mount stack looking for an autofs mount that
- * has the requested mount type (ie. indirect, direct or offset).
- */
-static int autofs_dev_ioctl_find_sbi_type(struct nameidata *nd, unsigned int type)
+static int test_by_dev(struct path *path, void *p)
 {
-	struct dentry *dentry;
-	struct autofs_info *ino;
-	unsigned int err;
-
-	err = -ENOENT;
-
-	/* Lookup the dentry name at the base of our mount point */
-	dentry = d_lookup(nd->path.dentry, &nd->last);
-	if (!dentry)
-		goto out;
-
-	dput(nd->path.dentry);
-	nd->path.dentry = dentry;
-
-	/* And follow the mount stack looking for our autofs mount */
-	while (follow_down(&nd->path.mnt, &nd->path.dentry)) {
-		ino = autofs4_dentry_ino(nd->path.dentry);
-		if (ino && ino->sbi->type & type) {
-			err = 0;
-			break;
-		}
-	}
-out:
-	return err;
+	return path->dentry->d_sb->s_dev == *(dev_t *)p;
 }
 
-static void autofs_dev_ioctl_fd_install(unsigned int fd, struct file *file)
+static int test_by_type(struct path *path, void *p)
 {
-	struct files_struct *files = current->files;
-	struct fdtable *fdt;
-
-	spin_lock(&files->file_lock);
-	fdt = files_fdtable(files);
-	BUG_ON(fdt->fd[fd] != NULL);
-	rcu_assign_pointer(fdt->fd[fd], file);
-	FD_SET(fd, fdt->close_on_exec);
-	spin_unlock(&files->file_lock);
+	struct autofs_info *ino = autofs4_dentry_ino(path->dentry);
+	return ino && ino->sbi->type & *(unsigned *)p;
 }
 
-
 /*
  * Open a file descriptor on the autofs mount point corresponding
  * to the given path and device number (aka. new_encode_dev(sb->s_dev)).
  */
-static int autofs_dev_ioctl_open_mountpoint(const char *path, dev_t devid)
+static int autofs_dev_ioctl_open_mountpoint(const char *name, dev_t devid)
 {
-	struct file *filp;
-	struct nameidata nd;
 	int err, fd;
 
-	fd = get_unused_fd();
+	fd = get_unused_fd_flags(O_CLOEXEC);
 	if (likely(fd >= 0)) {
-		/* Get nameidata of the parent directory */
-		err = path_lookup(path, LOOKUP_PARENT, &nd);
+		struct file *filp;
+		struct path path;
+
+		err = find_autofs_mount(name, &path, test_by_dev, &devid);
 		if (err)
 			goto out;
 
 		/*
-		 * Search down, within the parent, looking for an
-		 * autofs super block that has the device number
+		 * Find autofs super block that has the device number
 		 * corresponding to the autofs fs we want to open.
 		 */
-		err = autofs_dev_ioctl_find_super(&nd, devid);
-		if (err) {
-			path_put(&nd.path);
-			goto out;
-		}
 
-		filp = dentry_open(nd.path.dentry, nd.path.mnt, O_RDONLY,
-				   current_cred());
+		filp = dentry_open(&path, O_RDONLY, current_cred());
+		path_put(&path);
 		if (IS_ERR(filp)) {
 			err = PTR_ERR(filp);
 			goto out;
 		}
 
-		autofs_dev_ioctl_fd_install(fd, filp);
+		fd_install(fd, filp);
 	}
 
 	return fd;
@@ -342,7 +279,7 @@ static int autofs_dev_ioctl_openmount(struct file *fp,
 	param->ioctlfd = -1;
 
 	path = param->path;
-	devid = param->openmount.devid;
+	devid = new_decode_dev(param->openmount.devid);
 
 	err = 0;
 	fd = autofs_dev_ioctl_open_mountpoint(path, devid);
@@ -412,6 +349,7 @@ static int autofs_dev_ioctl_setpipefd(struct file *fp,
 {
 	int pipefd;
 	int err = 0;
+	struct pid *new_pid = NULL;
 
 	if (param->setpipefd.pipefd == -1)
 		return -EINVAL;
@@ -423,18 +361,33 @@ static int autofs_dev_ioctl_setpipefd(struct file *fp,
 		mutex_unlock(&sbi->wq_mutex);
 		return -EBUSY;
 	} else {
-		struct file *pipe = fget(pipefd);
-		if (!pipe->f_op || !pipe->f_op->write) {
+		struct file *pipe;
+
+		new_pid = get_task_pid(current, PIDTYPE_PGID);
+
+		if (ns_of_pid(new_pid) != ns_of_pid(sbi->oz_pgrp)) {
+			AUTOFS_WARN("Not allowed to change PID namespace");
+			err = -EINVAL;
+			goto out;
+		}
+
+		pipe = fget(pipefd);
+		if (!pipe) {
+			err = -EBADF;
+			goto out;
+		}
+		if (autofs_prepare_pipe(pipe) < 0) {
 			err = -EPIPE;
 			fput(pipe);
 			goto out;
 		}
-		sbi->oz_pgrp = task_pgrp_nr(current);
+		swap(sbi->oz_pgrp, new_pid);
 		sbi->pipefd = pipefd;
 		sbi->pipe = pipe;
 		sbi->catatonic = 0;
 	}
 out:
+	put_pid(new_pid);
 	mutex_unlock(&sbi->wq_mutex);
 	return err;
 }
@@ -477,8 +430,7 @@ static int autofs_dev_ioctl_requester(struct file *fp,
 				      struct autofs_dev_ioctl *param)
 {
 	struct autofs_info *ino;
-	struct nameidata nd;
-	const char *path;
+	struct path path;
 	dev_t devid;
 	int err = -ENOENT;
 
@@ -487,32 +439,24 @@ static int autofs_dev_ioctl_requester(struct file *fp,
 		goto out;
 	}
 
-	path = param->path;
 	devid = sbi->sb->s_dev;
 
 	param->requester.uid = param->requester.gid = -1;
 
-	/* Get nameidata of the parent directory */
-	err = path_lookup(path, LOOKUP_PARENT, &nd);
+	err = find_autofs_mount(param->path, &path, test_by_dev, &devid);
 	if (err)
 		goto out;
 
-	err = autofs_dev_ioctl_find_super(&nd, devid);
-	if (err)
-		goto out_release;
-
-	ino = autofs4_dentry_ino(nd.path.dentry);
+	ino = autofs4_dentry_ino(path.dentry);
 	if (ino) {
 		err = 0;
-		autofs4_expire_wait(nd.path.dentry);
+		autofs4_expire_wait(path.dentry);
 		spin_lock(&sbi->fs_lock);
-		param->requester.uid = ino->uid;
-		param->requester.gid = ino->gid;
+		param->requester.uid = from_kuid_munged(current_user_ns(), ino->uid);
+		param->requester.gid = from_kgid_munged(current_user_ns(), ino->gid);
 		spin_unlock(&sbi->fs_lock);
 	}
-
-out_release:
-	path_put(&nd.path);
+	path_put(&path);
 out:
 	return err;
 }
@@ -557,12 +501,11 @@ static int autofs_dev_ioctl_askumount(struct file *fp,
  * mount if there is one or 0 if it isn't a mountpoint.
  *
  * If we aren't supplied with a file descriptor then we
- * lookup the nameidata of the path and check if it is the
- * root of a mount. If a type is given we are looking for
- * a particular autofs mount and if we don't find a match
- * we return fail. If the located nameidata path is the
- * root of a mount we return 1 along with the super magic
- * of the mount or 0 otherwise.
+ * lookup the path and check if it is the root of a mount.
+ * If a type is given we are looking for a particular autofs
+ * mount and if we don't find a match we return fail. If the
+ * located path is the root of a mount we return 1 along with
+ * the super magic of the mount or 0 otherwise.
  *
  * In both cases the the device number (as returned by
  * new_encode_dev()) is also returned.
@@ -571,8 +514,8 @@ static int autofs_dev_ioctl_ismountpoint(struct file *fp,
 					 struct autofs_sb_info *sbi,
 					 struct autofs_dev_ioctl *param)
 {
-	struct nameidata nd;
-	const char *path;
+	struct path path;
+	const char *name;
 	unsigned int type;
 	unsigned int devid, magic;
 	int err = -ENOENT;
@@ -582,71 +525,45 @@ static int autofs_dev_ioctl_ismountpoint(struct file *fp,
 		goto out;
 	}
 
-	path = param->path;
+	name = param->path;
 	type = param->ismountpoint.in.type;
 
 	param->ismountpoint.out.devid = devid = 0;
 	param->ismountpoint.out.magic = magic = 0;
 
 	if (!fp || param->ioctlfd == -1) {
-		if (autofs_type_any(type)) {
-			struct super_block *sb;
-
-			err = path_lookup(path, LOOKUP_FOLLOW, &nd);
-			if (err)
-				goto out;
-
-			sb = nd.path.dentry->d_sb;
-			devid = new_encode_dev(sb->s_dev);
-		} else {
-			struct autofs_info *ino;
-
-			err = path_lookup(path, LOOKUP_PARENT, &nd);
-			if (err)
-				goto out;
-
-			err = autofs_dev_ioctl_find_sbi_type(&nd, type);
-			if (err)
-				goto out_release;
-
-			ino = autofs4_dentry_ino(nd.path.dentry);
-			devid = autofs4_get_dev(ino->sbi);
-		}
-
+		if (autofs_type_any(type))
+			err = kern_path_mountpoint(AT_FDCWD,
+						   name, &path, LOOKUP_FOLLOW);
+		else
+			err = find_autofs_mount(name, &path,
+						test_by_type, &type);
+		if (err)
+			goto out;
+		devid = new_encode_dev(path.dentry->d_sb->s_dev);
 		err = 0;
-		if (nd.path.dentry->d_inode &&
-		    nd.path.mnt->mnt_root == nd.path.dentry) {
+		if (path.mnt->mnt_root == path.dentry) {
 			err = 1;
-			magic = nd.path.dentry->d_inode->i_sb->s_magic;
+			magic = path.dentry->d_sb->s_magic;
 		}
 	} else {
-		dev_t dev = autofs4_get_dev(sbi);
+		dev_t dev = sbi->sb->s_dev;
 
-		err = path_lookup(path, LOOKUP_PARENT, &nd);
+		err = find_autofs_mount(name, &path, test_by_dev, &dev);
 		if (err)
 			goto out;
 
-		err = autofs_dev_ioctl_find_super(&nd, dev);
-		if (err)
-			goto out_release;
-
-		devid = dev;
+		devid = new_encode_dev(dev);
 
-		err = have_submounts(nd.path.dentry);
+		err = have_submounts(path.dentry);
 
-		if (nd.path.mnt->mnt_mountpoint != nd.path.mnt->mnt_root) {
-			if (follow_down(&nd.path.mnt, &nd.path.dentry)) {
-				struct inode *inode = nd.path.dentry->d_inode;
-				magic = inode->i_sb->s_magic;
-			}
-		}
+		if (follow_down_one(&path))
+			magic = path.dentry->d_sb->s_magic;
 	}
 
 	param->ismountpoint.out.devid = devid;
 	param->ismountpoint.out.magic = magic;
-
-out_release:
-	path_put(&nd.path);
+	path_put(&path);
 out:
 	return err;
 }
@@ -756,12 +673,6 @@ static int _autofs_dev_ioctl(unsigned int command, struct autofs_dev_ioctl __use
 			goto out;
 		}
 
-		if (!fp->f_op) {
-			err = -ENOTTY;
-			fput(fp);
-			goto out;
-		}
-
 		sbi = autofs_dev_ioctl_sbi(fp);
 		if (!sbi || sbi->magic != AUTOFS_SBI_MAGIC) {
 			err = -EINVAL;
@@ -813,16 +724,20 @@ static const struct file_operations _dev_ioctl_fops = {
 	.unlocked_ioctl	 = autofs_dev_ioctl,
 	.compat_ioctl = autofs_dev_ioctl_compat,
 	.owner	 = THIS_MODULE,
+	.llseek = noop_llseek,
 };
 
 static struct miscdevice _autofs_dev_ioctl_misc = {
-	.minor 		= MISC_DYNAMIC_MINOR,
+	.minor		= AUTOFS_MINOR,
 	.name  		= AUTOFS_DEVICE_NAME,
 	.fops  		= &_dev_ioctl_fops
 };
 
+MODULE_ALIAS_MISCDEV(AUTOFS_MINOR);
+MODULE_ALIAS("devname:autofs");
+
 /* Register/deregister misc character device */
-int autofs_dev_ioctl_init(void)
+int __init autofs_dev_ioctl_init(void)
 {
 	int r;