Messages in this thread | | | From | Xi Wang <> | Date | Mon, 29 Apr 2013 03:48:29 -0400 | Subject | Re: [PATCH v2 net-next 2/3] x86: bpf_jit_comp: support BPF_S_ANC_SECCOMP_LD_W instruction |
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On Sat, Apr 27, 2013 at 9:21 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote: > I would feel more comfortable if you added : > > if (seen & SEEN_DATAREF) { > pr_err_once("SECCOMP_LD_W assertion failed\n"): > goto out; > } > > This way, if BPF is changed in the future, but not the x86 JIT, we > can have a working kernel. > > Ideally, we should add a SEEN_SKBREF to make sure rdi value can be > scratched, or you just push %rdi/pop %rdi, its only one byte > instructions.
Adding SEEN_SKBREF sounds like a good idea. :)
> Or completely optimize the thing and not call seccomp_bpf_load() at all.
This would be cool.
> (current would be loaded once in r9, task_pt_regs() would be loaded once > in r8)
Both syscall_get_arch() and syscall_get_arguments() need to test for the TS_COMPAT bit (in task_thread_info(current)->status); we should load that once, too.
Thanks for the comments. Will try a v3.
- xi
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