On Fri, 3 May 2013 13:47:59 -0400 Dwight Engen <dwight.en...@oracle.com> wrote:
> On Fri, 3 May 2013 12:23:29 -0500 > Serge Hallyn <serge.hal...@ubuntu.com> wrote: > > > Quoting Dwight Engen (dwight.en...@oracle.com): > > > On Fri, 3 May 2013 11:17:08 -0500 > > > Serge Hallyn <serge.hal...@ubuntu.com> wrote: > > > > > > > can that be correct? That changes the value of the > > > > pointer. NLMSG_DATA adds aligned sizeof(struct nlmsghdr). > > > > > > The current code is relying on the fact that our genlmsg looks > > > like this: > > > > > > struct genlmsg { > > > struct nlmsghdr nlmsghdr; > > > struct genlmsghdr genlmsghdr; > > > }; > > > > > > so NLMSG_DATA(&request->nlmsghdr) == genlmsghdr (I think sizeof > > > struct nlmsghdr will make genlmsghdr be aligned anyway?). Right > > > now lxc doesn't use this code so I cannot test it in lxc, but let > > > me write a test program that dumps the pointers using the old way > > > and the new way. We do have a 2*PAGE_SIZE buffer these point to > > > so I'm sure its not overflowing, so maybe we do just want to > > > ignore coverity. > > > > Thanks, I'll go ahead and apply the rest and hold off on this one. > > Yeah I agree we should hold off. The following test program shows them > equivalent, but using NLMSG_DATA may be more appropriate. The > commented out __attribute__ ((aligned(4))); in genl.h make me > suspicous this has come up before. Maybe I can look into a way to > make coverity happy instead. Just to follow up, I did check what libnl does, and it has nlmsg_data() that just adds NLMSG_HDRLEN to a nlmsghdr pointer. This is equivalent to of our use of NLMSG_DATA so I think we should just leave the code as is and not apply this patch. ------------------------------------------------------------------------------ AlienVault Unified Security Management (USM) platform delivers complete security visibility with the essential security capabilities. Easily and efficiently configure, manage, and operate all of your security controls from a single console and one unified framework. Download a free trial. http://p.sf.net/sfu/alienvault_d2d _______________________________________________ Lxc-devel mailing list Lxc-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/lxc-devel