1. 01 Dec, 2018 37 commits
  2. 27 Nov, 2018 3 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
    • Eric Biggers's avatar
      HID: uhid: forbid UHID_CREATE under KERNEL_DS or elevated privileges · 540f8937
      Eric Biggers authored
      commit 8c01db76 upstream.
      
      When a UHID_CREATE command is written to the uhid char device, a
      copy_from_user() is done from a user pointer embedded in the command.
      When the address limit is KERNEL_DS, e.g. as is the case during
      sys_sendfile(), this can read from kernel memory.  Alternatively,
      information can be leaked from a setuid binary that is tricked to write
      to the file descriptor.  Therefore, forbid UHID_CREATE in these cases.
      
      No other commands in uhid_char_write() are affected by this bug and
      UHID_CREATE is marked as "obsolete", so apply the restriction to
      UHID_CREATE only rather than to uhid_char_write() entirely.
      
      Thanks to Dmitry Vyukov for adding uhid definitions to syzkaller and to
      Jann Horn for commit 9da3f2b7 ("x86/fault: BUG() when uaccess
      helpers fault on kernel addresses"), allowing this bug to be found.
      
      Reported-by: syzbot+72473edc9bf4eb1c6556@syzkaller.appspotmail.com
      Fixes: d365c6cf ("HID: uhid: add UHID_CREATE and UHID_DESTROY events")
      Cc: <stable@vger.kernel.org> # v3.6+
      Cc: Jann Horn <jannh@google.com>
      Cc: Andy Lutomirski <luto@kernel.org>
      Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
      Reviewed-by: default avatarJann Horn <jannh@google.com>
      Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
      Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      540f8937