1. 01 Dec, 2018 38 commits
  2. 27 Nov, 2018 2 commits
    • Greg Kroah-Hartman's avatar
      Linux 4.14.84 · 4201a586
      Greg Kroah-Hartman authored
      4201a586
    • Ilya Dryomov's avatar
      libceph: fall back to sendmsg for slab pages · 3c7f1671
      Ilya Dryomov authored
      commit 7e241f64 upstream.
      
      skb_can_coalesce() allows coalescing neighboring slab objects into
      a single frag:
      
        return page == skb_frag_page(frag) &&
               off == frag->page_offset + skb_frag_size(frag);
      
      ceph_tcp_sendpage() can be handed slab pages.  One example of this is
      XFS: it passes down sector sized slab objects for its metadata I/O.  If
      the kernel client is co-located on the OSD node, the skb may go through
      loopback and pop on the receive side with the exact same set of frags.
      When tcp_recvmsg() attempts to copy out such a frag, hardened usercopy
      complains because the size exceeds the object's allocated size:
      
        usercopy: kernel memory exposure attempt detected from ffff9ba917f20a00 (kmalloc-512) (1024 bytes)
      
      Although skb_can_coalesce() could be taught to return false if the
      resulting frag would cross a slab object boundary, we already have
      a fallback for non-refcounted pages.  Utilize it for slab pages too.
      
      Cc: stable@vger.kernel.org # 4.8+
      Signed-off-by: default avatarIlya Dryomov <idryomov@gmail.com>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      3c7f1671