agent: fix crashers if API requests empty

Question

Check the validity of the AddARPNeighbors, UpdateInterface and UpdateRoutes, APIs before using to avoid crashing the agent.

Fixes: #949, #950, #955.

Signed-off-by: James O. D. Hunt

该提问来源于开源项目：kata-containers/kata-containers

Answer 1

fwiw, I've reviewed all the API calls: these three calls are the only one that are passed a pointer value which wasn't being checked. All the others are passed a struct, and hence are safer ;) Some struct elements themselves are pointers, but those are all checked (except for the string_user elements in CreateContainer and ExecProcess, but those are unused).