Re: [PATCH] fsnotify: preserve 64-bit pre-content ranges

[Jan Kara]

On Thu 15-10-26 20:57:01, Avi Weiss wrote:
> vfs_fallocate() and remap_verify_area() pass 64-bit lengths to
> fsnotify_file_area_perm(), which truncates them to size_t on
> 32-bit systems.
> 
> Use 64 bit (unsigned) types throughout the entire pre-content
> notification chain to keep the full range. The userspace range
> field is already 64-bits.
> 
> Fixes: 9740d17162de ("fsnotify: pass optional file access range in pre-content event")
> Signed-off-by: Avi Weiss <thnkslprpt@xxxxxxxxx>

Thanks. I've added the patch to my tree.

								Honza

> ---
> Tested on a 32-bit x86 kernel in QEMU with ext4 and
> FAN_CLASS_PRE_CONTENT / FAN_PRE_ACCESS with regular 
> (4KB), boundary, near-boundary, and beyond boundary counts.
> 
> requested count    before   with the fix
>           4096      4096           4096
>     4294967295         0     4294967296
>     4294967296         0     4294967296
>     4294971392      4096     4294971392
> 
> diff --git a/fs/notify/fanotify/fanotify.h b/fs/notify/fanotify/fanotify.h
> index 3710543dbf827..225919d7347bf 100644
> --- a/fs/notify/fanotify/fanotify.h
> +++ b/fs/notify/fanotify/fanotify.h
> @@ -441,7 +441,7 @@ struct fanotify_perm_event {
>  	struct fanotify_event fae;
>  	struct path path;
>  	loff_t pos;			/* FANOTIFY_NO_RANGE if unavailable */
> -	size_t count;
> +	u64 count;
>  	u32 response;			/* userspace answer to the event */
>  	unsigned short state;		/* state of the event */
>  	unsigned short watchdog_cnt;	/* already scanned by watchdog? */
> diff --git a/fs/notify/fsnotify.c b/fs/notify/fsnotify.c
> index 7e2f330fd2837..8657bb94dfa8b 100644
> --- a/fs/notify/fsnotify.c
> +++ b/fs/notify/fsnotify.c
> @@ -157,7 +157,7 @@ static inline __u32 fsnotify_object_watched(struct inode *inode, __u32 mnt_mask,
>  
>  /* Report pre-content event with optional range info */
>  int fsnotify_pre_content(const struct path *path, const loff_t *ppos,
> -			 size_t count)
> +			 u64 count)
>  {
>  	struct file_range range;
>  
> diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
> index bda798bc67bc5..a4a29b3650080 100644
> --- a/include/linux/fsnotify.h
> +++ b/include/linux/fsnotify.h
> @@ -135,7 +135,7 @@ int fsnotify_open_perm_and_set_mode(struct file *file);
>   * fsnotify_file_area_perm - permission hook before access to file range
>   */
>  static inline int fsnotify_file_area_perm(struct file *file, int perm_mask,
> -					  const loff_t *ppos, size_t count)
> +					  const loff_t *ppos, u64 count)
>  {
>  	/*
>  	 * filesystem may be modified in the context of permission events
> @@ -213,7 +213,7 @@ static inline int fsnotify_open_perm_and_set_mode(struct file *file)
>  }
>  
>  static inline int fsnotify_file_area_perm(struct file *file, int perm_mask,
> -					  const loff_t *ppos, size_t count)
> +					  const loff_t *ppos, u64 count)
>  {
>  	return 0;
>  }
> diff --git a/include/linux/fsnotify_backend.h b/include/linux/fsnotify_backend.h
> index 618eed4d6d724..a25ae4ed879c7 100644
> --- a/include/linux/fsnotify_backend.h
> +++ b/include/linux/fsnotify_backend.h
> @@ -323,7 +323,7 @@ struct fs_error_report {
>  struct file_range {
>  	const struct path *path;
>  	loff_t pos;
> -	size_t count;
> +	u64 count;
>  };
>  
>  static inline const struct path *file_range_path(const struct file_range *range)
> @@ -945,12 +945,12 @@ static inline void fsnotify_init_event(struct fsnotify_event *event)
>  	INIT_LIST_HEAD(&event->list);
>  }
>  int fsnotify_pre_content(const struct path *path, const loff_t *ppos,
> -			 size_t count);
> +			 u64 count);
>  
>  #else
>  
>  static inline int fsnotify_pre_content(const struct path *path,
> -				       const loff_t *ppos, size_t count)
> +				       const loff_t *ppos, u64 count)
>  {
>  	return 0;
>  }
> 
> base-commit: 045958acaa75205b31578cb22c4345e28dd2e4bf
> -- 
> 2.43.0
> 
-- 
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR