1. 20 Mar, 2015 1 commit
    • Daniel Borkmann's avatar
      net: cls_bpf: fix size mismatch on filter preparation · 709178a6
      Daniel Borkmann authored
      commit 7913ecf6 upstream.
      
      In cls_bpf_modify_existing(), we read out the number of filter blocks,
      do some sanity checks, allocate a block on that size, and copy over the
      BPF instruction blob from user space, then pass everything through the
      classic BPF checker prior to installation of the classifier.
      
      We should reject mismatches here, there are 2 scenarios: the number of
      filter blocks could be smaller than the provided instruction blob, so
      we do a partial copy of the BPF program, and thus the instructions will
      either be rejected from the verifier or a valid BPF program will be run;
      in the other case, we'll end up copying more than we're supposed to,
      and most likely the trailing garbage will be rejected by the verifier
      as well (i.e. we need to fit instruction pattern, ret {A,K} needs to be
      last instruction, load/stores must be correct, etc); in case not, we
      would leak memory when dumping back instruction patterns. The code should
      have only used nla_len() as Dave noted to avoid this from the beginning.
      Anyway, lets fix it by rejecting such load attempts.
      
      Fixes: 7d1d65cb ("net: sched: cls_bpf: add BPF-based classifier")
      Signed-off-by: default avatarDaniel Borkmann <dborkman@redhat.com>
      Acked-by: default avatarJiri Pirko <jiri@resnulli.us>
      Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      Signed-off-by: default avatarLuis Henriques <luis.henriques@canonical.com>
      709178a6
  2. 18 Mar, 2015 39 commits