On 10/03/2015 12:44 AM, Tycho Andersen wrote:
On Fri, Oct 02, 2015 at 02:10:24PM -0700, Kees Cook wrote:
...
Ok, how about, struct sock_filter insns[BPF_MAXINSNS]; insn_cnt = ptrace(PTRACE_SECCOMP_GET_FILTER, pid, insns, i);
Would also be good that when the storage buffer (insns) is NULL, it just returns you the number of sock_filter insns (or 0 when nothing attached). That would be consistent with classic socket filters (see sk_get_filter()), and user space could allocate a specific size instead of always passing in max insns.
when asking for the ith filter? It returns either the number of instructions, -EINVAL if something was wrong (i, pid, CONFIG_CHECKPOINT_RESTORE isn't enabled). While it would always succeed now, if/when the underlying filter was not created from a bpf classic filter, we can return -EMEDIUMTYPE? (Suggestions welcome, I picked this mostly based on what sounds nice.) Tycho
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