1. 26 1月, 2018 4 次提交
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      bpf: Add write access to tcp_sock and sock fields · b73042b8
      Lawrence Brakmo 提交于
      This patch adds a macro, SOCK_OPS_SET_FIELD, for writing to
      struct tcp_sock or struct sock fields. This required adding a new
      field "temp" to struct bpf_sock_ops_kern for temporary storage that
      is used by sock_ops_convert_ctx_access. It is used to store and recover
      the contents of a register, so the register can be used to store the
      address of the sk. Since we cannot overwrite the dst_reg because it
      contains the pointer to ctx, nor the src_reg since it contains the value
      we want to store, we need an extra register to contain the address
      of the sk.
      
      Also adds the macro SOCK_OPS_GET_OR_SET_FIELD that calls one of the
      GET or SET macros depending on the value of the TYPE field.
      Signed-off-by: NLawrence Brakmo <brakmo@fb.com>
      Acked-by: NAlexei Starovoitov <ast@kernel.org>
      Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      b73042b8
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      bpf: Make SOCK_OPS_GET_TCP struct independent · 34d367c5
      Lawrence Brakmo 提交于
      Changed SOCK_OPS_GET_TCP to SOCK_OPS_GET_FIELD and added 2
      arguments so now it can also work with struct sock fields.
      The first argument is the name of the field in the bpf_sock_ops
      struct, the 2nd argument is the name of the field in the OBJ struct.
      
      Previous: SOCK_OPS_GET_TCP(FIELD_NAME)
      New:      SOCK_OPS_GET_FIELD(BPF_FIELD, OBJ_FIELD, OBJ)
      
      Where OBJ is either "struct tcp_sock" or "struct sock" (without
      quotation). BPF_FIELD is the name of the field in the bpf_sock_ops
      struct and OBJ_FIELD is the name of the field in the OBJ struct.
      
      Although the field names are currently the same, the kernel struct names
      could change in the future and this change makes it easier to support
      that.
      
      Note that adding access to tcp_sock fields in sock_ops programs does
      not preclude the tcp_sock fields from being removed as long as we are
      willing to do one of the following:
      
        1) Return a fixed value (e.x. 0 or 0xffffffff), or
        2) Make the verifier fail if that field is accessed (i.e. program
          fails to load) so the user will know that field is no longer
          supported.
      Signed-off-by: NLawrence Brakmo <brakmo@fb.com>
      Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      34d367c5
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      bpf: Make SOCK_OPS_GET_TCP size independent · a33de397
      Lawrence Brakmo 提交于
      Make SOCK_OPS_GET_TCP helper macro size independent (before only worked
      with 4-byte fields.
      Signed-off-by: NLawrence Brakmo <brakmo@fb.com>
      Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      a33de397
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      bpf: Only reply field should be writeable · 2585cd62
      Lawrence Brakmo 提交于
      Currently, a sock_ops BPF program can write the op field and all the
      reply fields (reply and replylong). This is a bug. The op field should
      not have been writeable and there is currently no way to use replylong
      field for indices >= 1. This patch enforces that only the reply field
      (which equals replylong[0]) is writeable.
      
      Fixes: 40304b2a ("bpf: BPF support for sock_ops")
      Signed-off-by: NLawrence Brakmo <brakmo@fb.com>
      Acked-by: NYuchung Cheng <ycheng@google.com>
      Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
      2585cd62
  2. 24 1月, 2018 15 次提交
  3. 23 1月, 2018 21 次提交