[PATCH v3 3/7] tests: check decoding of netlink protocol

[Dmitry V. Levin]

On Thu, Jun 16, 2016 at 02:20:07PM +0000, Fabien Siron wrote:
> Quoting Dmitry V. Levin (2016-06-16 10:40:18)
> > On Wed, Jun 15, 2016 at 12:43:01PM +0000, Fabien Siron wrote:
> > [...]
> > > +static void
> > > +send_query(const int fd, const unsigned int pid_magic)
> > > +{
> > > +     struct {
> > > +             struct nlmsghdr nlh;
> > > +             char magic[4];
> > > +     } req = {
> > > +             .nlh = {
> > > +                     .nlmsg_len = sizeof(req),
> > > +                     .nlmsg_type = NLMSG_NOOP,
> > > +                     .nlmsg_flags = NLM_F_DUMP | NLM_F_REQUEST
> > > +             },
> > > +             .magic = "abcd"
> > > +     };
> > > +
> > > +     if (sendto(fd, &req, sizeof(req), MSG_DONTWAIT, NULL, 0) !=
> > > +         (unsigned) sizeof(req))
> > > +             perror_msg_and_skip("sendto");
> > > +
> > > +     printf("sendto(%d<NETLINK:[SOCK_DIAG:%u]>, {{len=%u, type=NLMSG_NOOP, "
> > > +            "flags=NLM_F_REQUEST|0x%x, seq=0, pid=0}, \"abcd\"}, %u, "
> > > +            "MSG_DONTWAIT, NULL, 0) = %u\n",
> > > +            fd, pid_magic, (unsigned) sizeof(req), NLM_F_DUMP,
> > > +            (unsigned) sizeof(req), (unsigned) sizeof(req));
> > 
> > I'd also add coverage for the following corner cases when
> > + data length equals to sizeof(struct nlmsghdr);
> > + data length is less than sizeof(struct nlmsghdr);
> > + data length is enough but data points to unmapped memory.
> > 
> I am not sure what you mean by "data".

By data I mean the 2nd argument of sendto, by data length I mean
the 3rd argument of sendto.

If only part of memory pointed by 2nd argument of sendto is mapped,
netlink parser won't be able to fetch it and is expected to print
something meaningfull.


-- 
ldv
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