Quoting Fabien Siron (2016-06-24 11:54:16)
> Quoting Dmitry V. Levin (2016-06-23 11:36:25)
> > On Thu, Jun 23, 2016 at 10:49:53AM +0000, Fabien Siron wrote:
> > > Quoting Dmitry V. Levin (2016-06-22 17:40:39)
> > > > On Wed, Jun 22, 2016 at 01:27:06PM +0000, Fabien Siron wrote:
> [...]
> > > > > + if (NLMSG_ALIGN(nlmsghdr->nlmsg_len) == 0 ||
> > > > > + NLMSG_ALIGN(nlmsghdr->nlmsg_len) > *len)
> > > > > + return 0;
> > > >
> > > > This is not going to happen with current implementation of nlmsg_fetch,
> > > > but if nlmsg_fetch changes and if this condition is true, then
> > > > *len remains unchanged and the subsequent nlmsg_fetch prints NULL.
> > >
> > > A way to fix that is to put *len to 0 in this test. But the problem is
> > > that
> > > nothing will be printed if sizeof(struct nlmsghdr) < *len <
> > > nlmsghdr->nlmsg_len.
> >
> > It's up to decode_netlink_msg to decide how to print such messages.
> >
> > decode_netlink has to be consistent. Every successfully fetched struct
> > nlmsghdr should be printed. When decode_netlink leaves some bytes of the
> > message undecoded, it has to print an indication.
>
> It already prints a string, what kind of indication do you want to add?
>
> So do you agree with this test for next_nlmsghdr:
>
> if (NLMSG_ALIGN(nlmsghdr->nlmsg_len) == 0 ||
> NLMSG_ALIGN(nlmsghdr->nlmsg_len) > *len) {
> *len = nlmsghdr->nlmsg_len;
> return 0;
> }
>
> Now, the subsequent nlmsg_fetch does not print NULL.
>
And of course, to add this at the beginning of fetch_nlmsg():
if (addr == 0)
return 0;
--
Fabien Siron
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