On 06/09/12 15:58, andros@xxxxxxxxxx wrote:
> From: Andy Adamson <andros@xxxxxxxxxx>
>
> The kernel gss_cl_ctx stores the context lifetime in gc_expiry, set
> by gssd in do_downcall() called by process_krb5_upcall(). The lifetime value is
> currently not related at all to the Kerberos TGS lifetime. It is either
> set to the value of gssd -t <timeout>, or to a kernel default of 3600
> seconds.
>
> Most of the time the gssd -t command line is not set, and a timeout value
> of zero was sent to the kernel triggering the use of the 3600 second kernel
> default timeout.
>
> In order for the kernel to properly know when to renew a context, or to stop
> buffering writes for a context about to expire, the gc_expiry value needs to
> reflect the credential lifetime used to create the context.
>
> Note that gss_inquire_cred returns the number of seconds for which the context
> remains valid in the lifetime_rec parameter.
>
> Send the actual TGS remaining lifetime to the kernel. It can still be
> overwritten by the gssd -t command line option, or set to the kernel default
> if the gss_inquire_cred call fails (which sets the lifetime_rec to zero).
>
> Signed-off-by: Andy Adamson <andros@xxxxxxxxxx>
Committed...
steved.
> ---
> utils/gssd/gssd_proc.c | 19 ++++++++++++++++---
> 1 files changed, 16 insertions(+), 3 deletions(-)
>
> diff --git a/utils/gssd/gssd_proc.c b/utils/gssd/gssd_proc.c
> index aa39435..c8d8142 100644
> --- a/utils/gssd/gssd_proc.c
> +++ b/utils/gssd/gssd_proc.c
> @@ -640,19 +640,22 @@ parse_enctypes(char *enctypes)
>
> static int
> do_downcall(int k5_fd, uid_t uid, struct authgss_private_data *pd,
> - gss_buffer_desc *context_token)
> + gss_buffer_desc *context_token, OM_uint32 lifetime_rec)
> {
> char *buf = NULL, *p = NULL, *end = NULL;
> unsigned int timeout = context_timeout;
> unsigned int buf_size = 0;
>
> - printerr(1, "doing downcall\n");
> + printerr(1, "doing downcall lifetime_rec %u\n", lifetime_rec);
> 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;
> p = buf = malloc(buf_size);
> end = buf + buf_size;
>
> + /* context_timeout set by -t option overrides context lifetime */
> + if (timeout == 0)
> + timeout = lifetime_rec;
> if (WRITE_BYTES(&p, end, uid)) goto out_err;
> if (WRITE_BYTES(&p, end, timeout)) goto out_err;
> if (WRITE_BYTES(&p, end, pd->pd_seq_win)) goto out_err;
> @@ -952,6 +955,7 @@ process_krb5_upcall(struct clnt_info *clp, uid_t uid, int fd, char *tgtname,
> char **dirname, *dir, *userdir;
> int create_resp = -1;
> int err, downcall_err = -EACCES;
> + OM_uint32 maj_stat, min_stat, lifetime_rec;
>
> printerr(1, "handling krb5 upcall (%s)\n", clp->dirname);
>
> @@ -1077,6 +1081,15 @@ 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 */
> + maj_stat = gss_inquire_context(&min_stat, pd.pd_ctx, NULL, NULL,
> + &lifetime_rec, NULL, NULL, NULL, NULL);
> +
> + if (maj_stat)
> + printerr(1, "WARNING: Failed to inquire context for lifetme "
> + "maj_stat %u\n", maj_stat);
> +
> 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",
> @@ -1084,7 +1097,7 @@ process_krb5_upcall(struct clnt_info *clp, uid_t uid, int fd, char *tgtname,
> goto out_return_error;
> }
>
> - do_downcall(fd, uid, &pd, &token);
> + do_downcall(fd, uid, &pd, &token, lifetime_rec);
>
> out:
> if (token.value)
> -- 1.7.7.6
>
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