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Re: [PATCH v4 5/7] xfs: create internal eofblocks structure with kuid_t

To: Dwight Engen <dwight.engen@xxxxxxxxxx>
Subject: Re: [PATCH v4 5/7] xfs: create internal eofblocks structure with kuid_t types
From: Dave Chinner <david@xxxxxxxxxxxxx>
Date: Fri, 19 Jul 2013 15:46:18 +1000
Cc: xfs@xxxxxxxxxxx
Delivered-to: xfs@xxxxxxxxxxx
In-reply-to: <20130717114740.77f7bcee@xxxxxxxxxx>
References: <20130717114740.77f7bcee@xxxxxxxxxx>
User-agent: Mutt/1.5.21 (2010-09-15)
On Wed, Jul 17, 2013 at 11:47:40AM -0400, Dwight Engen wrote:
> Have eofblocks ioctl convert uid_t to kuid_t into internal structure.
> Update internal filter matching to compare ids with kuid_t types.
> 
> Signed-off-by: Dwight Engen <dwight.engen@xxxxxxxxxx>
....
>  
> +static inline void
> +xfs_fs_eofblocks_to_internal(
> +     struct xfs_fs_eofblocks         *src,
> +     struct xfs_eofblocks            *dst)

I'd prefer that be named xfs_fs_eofblocks_from_user() to make it
clear that we don't trust the contents of src at all...

> +{
> +     dst->eof_flags = src->eof_flags;
> +     dst->eof_prid = src->eof_prid;
> +     dst->eof_min_file_size = src->eof_min_file_size;
> +     dst->eof_uid = make_kuid(current_user_ns(), src->eof_uid);
> +     dst->eof_gid = make_kgid(current_user_ns(), src->eof_gid);
> +}
> +
>  #endif
> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
> index 8edc780..abbbdcf 100644
> --- a/fs/xfs/xfs_ioctl.c
> +++ b/fs/xfs/xfs_ioctl.c
> @@ -1610,7 +1610,8 @@ xfs_file_ioctl(
>               return -error;
>  
>       case XFS_IOC_FREE_EOFBLOCKS: {
> -             struct xfs_eofblocks eofb;
> +             struct xfs_fs_eofblocks eofb;
> +             struct xfs_eofblocks keofb;
>  
>               if (copy_from_user(&eofb, arg, sizeof(eofb)))
>                       return -XFS_ERROR(EFAULT);
> @@ -1625,7 +1626,17 @@ xfs_file_ioctl(
>                   memchr_inv(eofb.pad64, 0, sizeof(eofb.pad64)))
>                       return -XFS_ERROR(EINVAL);
>  
> -             error = xfs_icache_free_eofblocks(mp, &eofb);
> +             xfs_fs_eofblocks_to_internal(&eofb, &keofb);
> +
> +             if (keofb.eof_flags & XFS_EOF_FLAGS_UID &&
> +                 !uid_valid(keofb.eof_uid))
> +                     return XFS_ERROR(EINVAL);
> +
> +             if (keofb.eof_flags & XFS_EOF_FLAGS_GID &&
> +                 !gid_valid(keofb.eof_gid))
> +                     return XFS_ERROR(EINVAL);

And I think these two checks should be in
xfs_fs_eofblocks_from_user(), hence pushing all the conversion and
validation of the user-supplied parameters into the one function.

Also, we need to return negative errors from this function....

> +             error = xfs_icache_free_eofblocks(mp, &keofb);
>               return -error;

                return -xfs_icache_free_eofblocks(mp, &keofb);

Cheers,

Dave.
-- 
Dave Chinner
david@xxxxxxxxxxxxx

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