On 10/09/2017 07:59 PM, Jesper Dangaard Brouer wrote:
[...]
+static void *cpu_map_lookup_elem(struct bpf_map *map, void *key)
+{
+ struct bpf_cpu_map_entry *rcpu =
+ __cpu_map_lookup_elem(map, *(u32 *)key);
+
+ return rcpu ? &rcpu->qsize : NULL;
I still think from my prior email/comment that we should use per-cpu
scratch buffer here. Would be nice to keep the guarantee that noone
can modify it, it's just a tiny change.
Well, it's no-longer really needed, right(?), as this patchset update,
change that bpf-side cannot invoke this. The userspace-side reading
this will get a copy.
Ah sorry, you're right, the related change happens in later patch, I
missed that; would be good to avoid a split in future or other option
is to forbid usage initially in check_map_func_compatibility() by
bailing out in BPF_MAP_TYPE_CPUMAP case unconditionally, and then
enabling it for BPF_FUNC_redirect_map in next step, such that should
someone accidentally only backport this patch, we don't allow for
unintended misuse.
Thanks,
Daniel
