From 8213acaf93f748d7d0efe085aded3ab9b6871e9b Mon Sep 17 00:00:00 2001 From: Andy Adamson Date: Thu, 18 Oct 2012 13:21:09 -0400 Subject: [PATCH] GSSD: Pass GSS_context lifetime to the kernel. From: Andy Adamson 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 , 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 Signed-off-by: Steve Dickson --- utils/gssd/gssd_proc.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) diff --git a/utils/gssd/gssd_proc.c b/utils/gssd/gssd_proc.c index 336f3e9..b9a898e 100644 --- a/utils/gssd/gssd_proc.c +++ b/utils/gssd/gssd_proc.c @@ -659,19 +659,22 @@ 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; @@ -954,6 +957,7 @@ process_krb5_upcall(struct clnt_info *clp, uid_t uid, int fd, char *tgtname, char **dirname; 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); @@ -1064,6 +1068,15 @@ 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", @@ -1071,7 +1084,7 @@ 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) -- 2.39.5