Vivek Goyal <vgoyal at redhat.com> writes: > On Mon, Nov 05, 2012 at 11:44:48AM -0800, Eric W. Biederman wrote: >> Vivek Goyal <vgoyal at redhat.com> writes: >> >> > On Fri, Nov 02, 2012 at 02:32:48PM -0700, Eric W. Biederman wrote: >> >> >> >> It needs to be checked but /sbin/kexec should not use any functions that >> >> trigger nss switch. No user or password or host name lookup should be >> >> happening. >> > >> > I also think that we don't call routines which trigger nss switch but >> > be probably can't rely on that as somebody might introduce it in >> > future. So we need more robust mechanism to prevent it than just code >> > inspection. >> >> The fact that we shouldn't use those routines is enough to let us >> walk down a path where they are not used. Either with a static glibc >> linked told to use no nss modules (--enable-static-nss ?), or with >> another more restricted libc. > > I installed glibc-static and built kexec-tools using gcc "-static" option. > It built just fine and infact kdump is working with it. > > Size of new kexec binary is around 1.4MB. > > Did not get any warning w.r.t nss, so I am assuming we are not calling > any relevant functions. > > I did try building my own libc using --enable-static-nss but it does not > seem to have built static versions of libnss*. Will look more into it > and try linking kexec with this new glibc and see if that works. > > Also tried playing with klibc and uclibc a bit but can't get anything > going quickly. Sounds good. It has been about a year since I looked but kexec built uclibc just fine last time I tried it. Eric
