Re: [PATCH] sg, bsg: mitigate read/write abuse, block uaccess in release

[Al Viro]

On Fri, Jun 15, 2018 at 05:23:35PM +0200, Jann Horn wrote:

> I've mostly copypasted ib_safe_file_access() over as
> scsi_safe_file_access() because I couldn't find a good common header -
> please tell me if you know a better way.
> The duplicate pr_err_once() calls are so that each of them fires once;
> otherwise, this would probably have to be a macro.
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Cc: <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Jann Horn <jannh@xxxxxxxxxx>
> ---

WTF do you mean, in ->release()?  That makes no sense whatsoever -
what kind of copy_{to,from}_user() would be possible in there?