On Mon, 14 Apr 2014 11:07:37 -0400
Steve Dickson <SteveD@xxxxxxxxxx> wrote:
> Hey Jeff,
>
> Just a couple nit....
>
> On 04/10/2014 04:31 PM, Jeff Layton wrote:
> > ...and pass it to the kernel in the downcall. Legacy kernels will just
> > ignore the extra data, but with a proposed kernel patch the kernel will
> > grab this info and use it to verify requests on the v4.0 callback
> > channel.
> >
> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> > ---
> > utils/gssd/gssd_proc.c | 39 ++++++++++++++++++++++++++++-----------
> > 1 file changed, 28 insertions(+), 11 deletions(-)
> >
> > diff --git a/utils/gssd/gssd_proc.c b/utils/gssd/gssd_proc.c
> > index 7387cce010cf..d95e39416c28 100644
> > --- a/utils/gssd/gssd_proc.c
> > +++ b/utils/gssd/gssd_proc.c
> > @@ -77,6 +77,7 @@
> > #include "context.h"
> > #include "nfsrpc.h"
> > #include "nfslib.h"
> > +#include "gss_names.h"
> >
> > /*
> > * pollarray:
> > @@ -683,16 +684,19 @@ parse_enctypes(char *enctypes)
> >
> > static void
> > do_downcall(int k5_fd, uid_t uid, struct authgss_private_data *pd,
> > - gss_buffer_desc *context_token, OM_uint32 lifetime_rec)
> > + gss_buffer_desc *context_token, OM_uint32 lifetime_rec,
> > + gss_buffer_desc *acceptor)
> > {
> > char *buf = NULL, *p = NULL, *end = NULL;
> > unsigned int timeout = context_timeout;
> > unsigned int buf_size = 0;
> >
> > - printerr(1, "doing downcall lifetime_rec %u\n", lifetime_rec);
> > + printerr(1, "doing downcall: lifetime_rec=%u acceptor=%.*s\n",
> > + lifetime_rec, acceptor->length, acceptor->value);
> > buf_size = sizeof(uid) + sizeof(timeout) + sizeof(pd->pd_seq_win) +
> > sizeof(pd->pd_ctx_hndl.length) + pd->pd_ctx_hndl.length +
> > - sizeof(context_token->length) + context_token->length;
> > + sizeof(context_token->length) + context_token->length +
> > + acceptor->length;
> > p = buf = malloc(buf_size);
> > if (!buf)
> > goto out_err;
> > @@ -707,6 +711,8 @@ do_downcall(int k5_fd, uid_t uid, struct authgss_private_data *pd,
> > if (WRITE_BYTES(&p, end, pd->pd_seq_win)) goto out_err;
> > if (write_buffer(&p, end, &pd->pd_ctx_hndl)) goto out_err;
> > if (write_buffer(&p, end, context_token)) goto out_err;
> > + if (acceptor->length > 0 &&
> > + write_buffer(&p, end, acceptor)) goto out_err;
> >
> > if (write(k5_fd, buf, p - buf) < p - buf) goto out_err;
> > free(buf);
> > @@ -1034,6 +1040,9 @@ process_krb5_upcall(struct clnt_info *clp, uid_t uid, int fd, char *tgtname,
> > gss_cred_id_t gss_cred;
> > OM_uint32 maj_stat, min_stat, lifetime_rec;
> > pid_t pid;
> > + gss_name_t gacceptor;
> > + gss_OID mech;
> > + gss_buffer_desc acceptor = {0};
> >
> > pid = fork();
> > switch(pid) {
> > @@ -1174,15 +1183,22 @@ process_krb5_upcall(struct clnt_info *clp, uid_t uid, int fd, char *tgtname,
> > goto out_return_error;
> > }
> >
> > - /* Grab the context lifetime to pass to the kernel. lifetime_rec
> > - * is set to zero on error */
> Why get rid of this comment instead of updating it?
>
I suppose I could do that. Would you prefer I respin and update that
comment instead?
> > - maj_stat = gss_inquire_context(&min_stat, pd.pd_ctx, NULL, NULL,
> > - &lifetime_rec, NULL, NULL, NULL, NULL);
> > + maj_stat = gss_inquire_context(&min_stat, pd.pd_ctx, NULL, &gacceptor,
> > + &lifetime_rec, &mech, NULL, NULL, NULL);
> >
> > - if (maj_stat)
> > - printerr(1, "WARNING: Failed to inquire context for lifetme "
> > - "maj_stat %u\n", maj_stat);
> > + if (maj_stat != GSS_S_COMPLETE) {
> > + printerr(1, "WARNING: Failed to inquire context "
> > + "maj_stat (0x%x)\n", maj_stat);
> > + } else {
> > + get_hostbased_client_buffer(gacceptor, mech, &acceptor);
> > + gss_release_name(&min_stat, &gacceptor);
> > + }
> >
> > + /*
> > + * The serialization can mean turning the ctx into a lucid context. If
> > + * that happens then the original ctx is no longer valid, so we mustn't
> > + * try to use if after this point.
> I'm not sure what you are trying to say here...
>
> steved.
>
Just a semi-helpful context for posterity...
On my initial attempt, I tried to change the code around to grab the
lifetime and acceptor out of the context in do_downcall. That didn't
work, because once you call serialize_context_for_kernel, the GSS
context is turned into a "lucid context". At that point, things like
gss_inquire_context no longer work on it.
IOW, once you call serialize_context_for_kernel, you can't count on
being able to do anything useful with pd.pd_ctx at all.
> > + */
> > if (serialize_context_for_kernel(&pd.pd_ctx, &token, &krb5oid, NULL)) {
> > printerr(0, "WARNING: Failed to serialize krb5 context for "
> > "user with uid %d for server %s\n",
> > @@ -1190,9 +1206,10 @@ process_krb5_upcall(struct clnt_info *clp, uid_t uid, int fd, char *tgtname,
> > goto out_return_error;
> > }
> >
> > - do_downcall(fd, uid, &pd, &token, lifetime_rec);
> > + do_downcall(fd, uid, &pd, &token, lifetime_rec, &acceptor);
> >
> > out:
> > + gss_release_buffer(&min_stat, &acceptor);
> > if (token.value)
> > free(token.value);
> > #ifdef HAVE_AUTHGSS_FREE_PRIVATE_DATA
> >
--
Jeff Layton <jlayton@xxxxxxxxxx>
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