lkml.org 
[lkml]   [2020]   [Jul]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRE: [PATCH 03/26] bpfilter: reject kernel addresses
    Date
    From: Christoph Hellwig
    > Sent: 23 July 2020 07:09
    >
    > The bpfilter user mode helper processes the optval address using
    > process_vm_readv. Don't send it kernel addresses fed under
    > set_fs(KERNEL_DS) as that won't work.

    What sort of operations is the bpf filter doing on the sockopt buffers?

    Any attempts to reject some requests can be thwarted by a second
    application thread modifying the buffer after the bpf filter has
    checked that it allowed.

    You can't do security by reading a user buffer twice.

    David

    -
    Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
    Registration No: 1397386 (Wales)

    \
     
     \ /
      Last update: 2020-07-23 16:43    [W:4.187 / U:0.224 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site