In message <CAM5tNy4XupPGXHMS0p0TK0Wf_zAg5bsOzx4C1K1e-_2b=3eyUw@mail.gmail.c om> , Rick Macklem writes: > On Thu, Jul 31, 2025 at 6:51=E2=80=AFAM Rick Macklem <rick.mack...@gmail.co= > m> wrote: > > > > On Thu, Jul 31, 2025 at 6:07=E2=80=AFAM Rick Macklem <rick.macklem@gmail.= > com> wrote: > > > > > > On Wed, Jul 30, 2025 at 9:24=E2=80=AFPM Benjamin Kaduk <bjkfbsd@gmail.c= > om> wrote: > > > > > > > > On Wed, Jul 30, 2025 at 10:36=E2=80=AFAM Rick Macklem <rick.macklem@g= > mail.com> wrote: > > > >> > > > >> On Mon, Jul 28, 2025 at 3:32=E2=80=AFPM Benjamin Kaduk <bjkfbsd@gmai= > l.com> wrote: > > > >> > > > > >> > On Mon, Jul 28, 2025 at 3:04=E2=80=AFPM Benjamin Kaduk <bjkfbsd@gm= > ail.com> wrote: > > > >> >> > > > >> >> > > > >> >> Note that MIT krb5 provides the gss_krb5_export_lucid_sec_context= > () API that does a lot of the work of getting useful bits out of an establi= > shed GSS security context. > > > >> >> > > > >> > > > > >> > > > > >> > > > > >> > > > > >> > And a bit more context on what is going on here and why kgssapi ha= > s to care: > > > >> > The GSS-API (RFC 2743) is all about a way to "establish a security= > context" (i.e., do crypto negotiation, authentication, sometimes authoriza= > tion, etc.) between two entities, the initiator and the acceprot, and then = > exchanging protected messages between the two (which can be either encrypte= > d or just integrity protection tags for otherweise cleartext data); later e= > xtensions included the ability to produce identical PRF output on both part= > ies, etc.. The details are "mechanism-specific", and for this purpose we'r= > e exclusively talking about the krb5 mechanism. The steps to establish the= > security context are complicated and sometimes fiddly, and in the general = > case can require a large number of round-trips between the initiator and ac= > ceptor before the security context is established. The individual message-= > protection parts are comparatively simple and amendable to implementation i= > n the kernel for processing efficiency. > > > >> > RFC 2743 also defines functions for GSS_Export_sec_context() and G= > SS_Import_sec_context(), that are designed essentially to pass information = > about an established security context from one process to another on the sa= > me machine (which are presumably using the same implementation and version = > of the implementation), so the contents of the exported blob are opaque and= > implementation-specific. We are abusing that mechanism to export informat= > ion about the security context that gssd has established and feed that info= > rmation into the kernel implementation of the per-message processing routin= > es. At present, this necessarily entails knowing the details of the implem= > entation-specific opaque blob that is the "export sec context token", which= > is what the sys/kgssapi/krb5/krb5_mech.c code is doing. But if we can get= > the information we want without breaking the abstraction barrier, such as = > via the gss_krb5_export_lucid_sec_context() API, we are in a more robust po= > sture overall and somewhat future-proofed against future evolution by MIT k= > rb5. > > > >> > (I note that recent Heimdal versions seem to also expose a gss_krb= > 5_export_lucid_sec_context() API, so part of the problem is just that the H= > eimdal in base is so old.) > > > >> > > > >> Well, here's some "not so good" news... > > > >> I've been trying to use gss_inquire_sec_context_by_oid(..) with the = > oid > > > >> for the GSS_KRB5_EXPORT_LUCID_SEC_CONTEXT_OID with version 1. > > > >> It kept failing. > > > >> The problem seems to be that "gctx->proto =3D=3D 4" in make_external= > _lucid_ctx_v1() > > > >> function. This function only knows about the 0 and 1 setting for gct= > x->proto. > > > >> > > > >> Any ideas, rick > > > >> > > > > > > > > > > > > I'm not seeing anything to suggest that a "gctx->proto" value of 4 is= > ever expected; it looks like it's supposed to just be 0 (for the legacy RF= > C 1964 format) or 1 (for the "CFX" format of RFC 4121, with wider sequence = > numbers for message-protection formats, etc.). So maybe it's worth posting= > your current WIP somewhere to take a closer look at what's going on. > > > > > > Yea, the debugging I did was flawed (I probably got the wrong offset > > > in the structure). > > > It is weird, though. If I do gss_inquire_sec_context_by_oid(&minor, ctx= > , > > > OID_FOR_GSS_INQUIRE_SSPI_SESSION_KEY, &key), it > > > works and gives me the key and encryption type. > > > > > > If I do the same, but with the 12 byte OID for LUCID v1 (the 11 bytes f= > rom the > > > string + a 1 byte), it returns major =3D=3D GSS_S_COMPLETE, but no data= > and > > > a weird 39756046(decimal) or 0x25ea10e(hex) minor. > > > (Oh, and I tried gss_krb5_export_lucid_sec_context() and got the same > > > weird error.) > > --> Now (after doing a "make buildworld"), gss_krb5_export_lucid_sec_cont= > ext() > > returns GSS_S_BAD_MECH. Looking at the src, that error has to be fro= > m > > gss_inquire_sec_context_by_oid(). So, same function fails, but a dif= > ferent > > error return? > > > > It looks like "gssint_get_mechanism (ctx->mech_type)" is failing. > > I'm currently just passing GSS_C_NULL_OID into gss_init_sec_context(), > > but I've also tried the Kerberos 9 byte OID (both work, in the sense that > > gss_init_sec_context() seems to work, except that the actual_mech_type > > returned by it has a bogus pointer in the reply). > > --> It looks like the "mech_type" field of "ctx" is busted, for some reas= > on? > > > > I'm going to try building krb5 from ports and linking to that, to see if = > it > > does the same thing. > Finally some good news... > All I did was "pkg install krb5" and then linked the gssd to the libraries = > in > /usr/local/lib and it worked!!
I will double check the generated gssapi.h from its .et files in krb5/lib/gssapi/generic. > > Now I can test/debug the changes. > > Btw, the stuff in /usr/local/include/gssapi are correct and not messed up > like the stuff in /usr/include/gssapi. (The ones in /usr/local/include defi= > ne > GSS_DLLIMP for example.) This is generated from one of the .et files. > > I'm going to leave figuring out why the libraries in /usr/lib are messed up > to someone else. > > rick > -- Cheers, Cy Schubert <cy.schub...@cschubert.com> FreeBSD UNIX: <c...@freebsd.org> Web: https://FreeBSD.org NTP: <c...@nwtime.org> Web: https://nwtime.org e**(i*pi)+1=0
