1. 12 10月, 2017 15 次提交
  2. 11 10月, 2017 13 次提交
  3. 10 10月, 2017 11 次提交
  4. 09 10月, 2017 1 次提交
    • S
      netfilter: xt_bpf: Fix XT_BPF_MODE_FD_PINNED mode of 'xt_bpf_info_v1' · 98589a09
      Shmulik Ladkani 提交于
      Commit 2c16d603 ("netfilter: xt_bpf: support ebpf") introduced
      support for attaching an eBPF object by an fd, with the
      'bpf_mt_check_v1' ABI expecting the '.fd' to be specified upon each
      IPT_SO_SET_REPLACE call.
      
      However this breaks subsequent iptables calls:
      
       # iptables -A INPUT -m bpf --object-pinned /sys/fs/bpf/xxx -j ACCEPT
       # iptables -A INPUT -s 5.6.7.8 -j ACCEPT
       iptables: Invalid argument. Run `dmesg' for more information.
      
      That's because iptables works by loading existing rules using
      IPT_SO_GET_ENTRIES to userspace, then issuing IPT_SO_SET_REPLACE with
      the replacement set.
      
      However, the loaded 'xt_bpf_info_v1' has an arbitrary '.fd' number
      (from the initial "iptables -m bpf" invocation) - so when 2nd invocation
      occurs, userspace passes a bogus fd number, which leads to
      'bpf_mt_check_v1' to fail.
      
      One suggested solution [1] was to hack iptables userspace, to perform a
      "entries fixup" immediatley after IPT_SO_GET_ENTRIES, by opening a new,
      process-local fd per every 'xt_bpf_info_v1' entry seen.
      
      However, in [2] both Pablo Neira Ayuso and Willem de Bruijn suggested to
      depricate the xt_bpf_info_v1 ABI dealing with pinned ebpf objects.
      
      This fix changes the XT_BPF_MODE_FD_PINNED behavior to ignore the given
      '.fd' and instead perform an in-kernel lookup for the bpf object given
      the provided '.path'.
      
      It also defines an alias for the XT_BPF_MODE_FD_PINNED mode, named
      XT_BPF_MODE_PATH_PINNED, to better reflect the fact that the user is
      expected to provide the path of the pinned object.
      
      Existing XT_BPF_MODE_FD_ELF behavior (non-pinned fd mode) is preserved.
      
      References: [1] https://marc.info/?l=netfilter-devel&m=150564724607440&w=2
                  [2] https://marc.info/?l=netfilter-devel&m=150575727129880&w=2Reported-by: NRafael Buchbinder <rafi@rbk.ms>
      Signed-off-by: NShmulik Ladkani <shmulik.ladkani@gmail.com>
      Acked-by: NWillem de Bruijn <willemb@google.com>
      Acked-by: NDaniel Borkmann <daniel@iogearbox.net>
      Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
      98589a09