bpf: add faked "ending" subprog

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There are quite a few code snippet like the following in verifier:

       subprog_start = 0;
       if (env->subprog_cnt == cur_subprog + 1)
               subprog_end = insn_cnt;
       else
               subprog_end = env->subprog_info[cur_subprog + 1].start;

The reason is there is no marker in subprog_info array to tell the end of
it.

We could resolve this issue by introducing a faked "ending" subprog.
The special "ending" subprog is with "insn_cnt" as start offset, so it is
serving as the end mark whenever we iterate over all subprogs.

Signed-off-by: Jiong Wang <jiong.wang@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

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Jiong Wang 2018-05-02 16:17:19 -04:00 • committed by Daniel Borkmann

parent 9c8105bd44

commit 4cb3d99c84

1 changed files with 14 additions and 20 deletions

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kernel/bpf/verifier.c

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