Re: [PATCH] vfs: move getname() from callers to do_mount()

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Sun, 14 Sep 2014 22:15:10 +0900
Seunghun Lee <waydi1@xxxxxxxxx> wrote:

> It would make more sense to pass char __user * instead of
> char * in callers of do_mount() and do getname() inside do_mount().
> 
> Suggested-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Seunghun Lee <waydi1@xxxxxxxxx>
> ---
>  arch/alpha/kernel/osf_sys.c | 23 ++++++++++-------------
>  fs/compat.c                 | 20 ++++++--------------
>  fs/namespace.c              | 29 ++++++++++++-----------------
>  include/linux/fs.h          |  3 ++-
>  4 files changed, 30 insertions(+), 45 deletions(-)
> 
> diff --git a/arch/alpha/kernel/osf_sys.c b/arch/alpha/kernel/osf_sys.c
> index 1402fcc..f9c732e 100644
> --- a/arch/alpha/kernel/osf_sys.c
> +++ b/arch/alpha/kernel/osf_sys.c
> @@ -446,7 +446,8 @@ struct procfs_args {
>   * unhappy with OSF UFS. [CHECKME]
>   */
>  static int
> -osf_ufs_mount(const char *dirname, struct ufs_args __user *args, int flags)
> +osf_ufs_mount(const char __user *dirname,
> +	      struct ufs_args __user *args, int flags)
>  {
>  	int retval;
>  	struct cdfs_args tmp;
> @@ -466,7 +467,8 @@ osf_ufs_mount(const char *dirname, struct ufs_args __user *args, int flags)
>  }
>  
>  static int
> -osf_cdfs_mount(const char *dirname, struct cdfs_args __user *args, int flags)
> +osf_cdfs_mount(const char __user *dirname,
> +	       struct cdfs_args __user *args, int flags)
>  {
>  	int retval;
>  	struct cdfs_args tmp;
> @@ -486,7 +488,8 @@ osf_cdfs_mount(const char *dirname, struct cdfs_args __user *args, int flags)
>  }
>  
>  static int
> -osf_procfs_mount(const char *dirname, struct procfs_args __user *args, int flags)
> +osf_procfs_mount(const char __user *dirname,
> +		 struct procfs_args __user *args, int flags)
>  {
>  	struct procfs_args tmp;
>  
> @@ -500,28 +503,22 @@ SYSCALL_DEFINE4(osf_mount, unsigned long, typenr, const char __user *, path,
>  		int, flag, void __user *, data)
>  {
>  	int retval;
> -	struct filename *name;
>  
> -	name = getname(path);
> -	retval = PTR_ERR(name);
> -	if (IS_ERR(name))
> -		goto out;
>  	switch (typenr) {
>  	case 1:
> -		retval = osf_ufs_mount(name->name, data, flag);
> +		retval = osf_ufs_mount(path, data, flag);
>  		break;
>  	case 6:
> -		retval = osf_cdfs_mount(name->name, data, flag);
> +		retval = osf_cdfs_mount(path, data, flag);
>  		break;
>  	case 9:
> -		retval = osf_procfs_mount(name->name, data, flag);
> +		retval = osf_procfs_mount(path, data, flag);
>  		break;
>  	default:
>  		retval = -EINVAL;
>  		printk("osf_mount(%ld, %x)\n", typenr, flag);
>  	}
> -	putname(name);
> - out:
> +
>  	return retval;
>  }
>  
> diff --git a/fs/compat.c b/fs/compat.c
> index 6205c24..b13df99 100644
> --- a/fs/compat.c
> +++ b/fs/compat.c
> @@ -794,7 +794,6 @@ COMPAT_SYSCALL_DEFINE5(mount, const char __user *, dev_name,
>  	char *kernel_type;
>  	unsigned long data_page;
>  	char *kernel_dev;
> -	struct filename *dir;
>  	int retval;
>  
>  	kernel_type = copy_mount_string(type);
> @@ -802,19 +801,14 @@ COMPAT_SYSCALL_DEFINE5(mount, const char __user *, dev_name,
>  	if (IS_ERR(kernel_type))
>  		goto out;
>  
> -	dir = getname(dir_name);
> -	retval = PTR_ERR(dir);
> -	if (IS_ERR(dir))
> -		goto out1;
> -
>  	kernel_dev = copy_mount_string(dev_name);
>  	retval = PTR_ERR(kernel_dev);
>  	if (IS_ERR(kernel_dev))
> -		goto out2;
> +		goto out1;
>  
>  	retval = copy_mount_options(data, &data_page);
>  	if (retval < 0)
> -		goto out3;
> +		goto out2;
>  
>  	retval = -EINVAL;
>  
> @@ -823,19 +817,17 @@ COMPAT_SYSCALL_DEFINE5(mount, const char __user *, dev_name,
>  			do_ncp_super_data_conv((void *)data_page);
>  		} else if (!strcmp(kernel_type, NFS4_NAME)) {
>  			if (do_nfs4_super_data_conv((void *) data_page))
> -				goto out4;
> +				goto out3;
>  		}
>  	}
>  
> -	retval = do_mount(kernel_dev, dir->name, kernel_type,
> +	retval = do_mount(kernel_dev, dir_name, kernel_type,
>  			flags, (void*)data_page);
>  
> - out4:
> -	free_page(data_page);
>   out3:
> -	kfree(kernel_dev);
> +	free_page(data_page);
>   out2:
> -	putname(dir);
> +	kfree(kernel_dev);
>   out1:
>  	kfree(kernel_type);
>   out:
> diff --git a/fs/namespace.c b/fs/namespace.c
> index bfd03c6..3e11e9e 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -2542,9 +2542,10 @@ char *copy_mount_string(const void __user *data)
>   * Therefore, if this magic number is present, it carries no information
>   * and must be discarded.
>   */
> -long do_mount(const char *dev_name, const char *dir_name,
> +long do_mount(const char *dev_name, const char __user *dir_name,
>  		const char *type_page, unsigned long flags, void *data_page)
>  {
> +	struct filename *kernel_dir;
>  	struct path path;
>  	int retval = 0;
>  	int mnt_flags = 0;
> @@ -2553,18 +2554,19 @@ long do_mount(const char *dev_name, const char *dir_name,
>  	if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
>  		flags &= ~MS_MGC_MSK;
>  
> -	/* Basic sanity checks */
> -
> -	if (!dir_name || !*dir_name || !memchr(dir_name, 0, PAGE_SIZE))
> -		return -EINVAL;
> +	kernel_dir = getname(dir_name);
> +	if (IS_ERR(kernel_dir)) {
> +		retval = PTR_ERR(kernel_dir);
> +		return retval;
> +	}
>  
>  	if (data_page)
>  		((char *)data_page)[PAGE_SIZE - 1] = 0;
>  
>  	/* ... and get the mountpoint */
> -	retval = kern_path(dir_name, LOOKUP_FOLLOW, &path);
> +	retval = kern_path(kernel_dir->name, LOOKUP_FOLLOW, &path);
>  	if (retval)
> -		return retval;
> +		goto dir_out;
>  
>  	retval = security_sb_mount(dev_name, &path,
>  				   type_page, flags, data_page);
> @@ -2619,6 +2621,8 @@ long do_mount(const char *dev_name, const char *dir_name,
>  				      dev_name, data_page);
>  dput_out:
>  	path_put(&path);
> +dir_out:
> +	putname(kernel_dir);
>  	return retval;
>  }
>  
> @@ -2787,7 +2791,6 @@ SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
>  {
>  	int ret;
>  	char *kernel_type;
> -	struct filename *kernel_dir;
>  	char *kernel_dev;
>  	unsigned long data_page;
>  
> @@ -2796,12 +2799,6 @@ SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
>  	if (IS_ERR(kernel_type))
>  		goto out_type;
>  
> -	kernel_dir = getname(dir_name);
> -	if (IS_ERR(kernel_dir)) {
> -		ret = PTR_ERR(kernel_dir);
> -		goto out_dir;
> -	}
> -
>  	kernel_dev = copy_mount_string(dev_name);
>  	ret = PTR_ERR(kernel_dev);
>  	if (IS_ERR(kernel_dev))
> @@ -2811,15 +2808,13 @@ SYSCALL_DEFINE5(mount, char __user *, dev_name, char __user *, dir_name,
>  	if (ret < 0)
>  		goto out_data;
>  
> -	ret = do_mount(kernel_dev, kernel_dir->name, kernel_type, flags,
> +	ret = do_mount(kernel_dev, dir_name, kernel_type, flags,
>  		(void *) data_page);
>  
>  	free_page(data_page);
>  out_data:
>  	kfree(kernel_dev);
>  out_dev:
> -	putname(kernel_dir);
> -out_dir:
>  	kfree(kernel_type);
>  out_type:
>  	return ret;
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index bb2c58c..72cb93f 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -1839,7 +1839,8 @@ extern struct vfsmount *kern_mount_data(struct file_system_type *, void *data);
>  extern void kern_unmount(struct vfsmount *mnt);
>  extern int may_umount_tree(struct vfsmount *);
>  extern int may_umount(struct vfsmount *);
> -extern long do_mount(const char *, const char *, const char *, unsigned long, void *);
> +extern long do_mount(const char *, const char __user *,
> +		     const char *, unsigned long, void *);
>  extern struct vfsmount *collect_mounts(struct path *);
>  extern void drop_collected_mounts(struct vfsmount *);
>  extern int iterate_mounts(int (*)(struct vfsmount *, void *), void *,

Looks sane.

Acked-by: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Ext4 Filesystem]     [Union Filesystem]     [Filesystem Testing]     [Ceph Users]     [Ecryptfs]     [AutoFS]     [Kernel Newbies]     [Share Photos]     [Security]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux Cachefs]     [Reiser Filesystem]     [Linux RAID]     [Samba]     [Device Mapper]     [CEPH Development]
  Powered by Linux