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From:   Scott Mayhew <smayhew@redhat.com>
To:     steved@redhat.com
Cc:     linux-nfs@vger.kernel.org
Subject: [nfs-utils PATCH v3] gssd: daemonize earlier
Date:   Thu, 17 Oct 2019 11:08:44 -0400
Message-Id: <20191017150844.21045-1-smayhew@redhat.com>
Sender: linux-nfs-owner@vger.kernel.org
Precedence: bulk

daemon_init() calls closeall() which closes all fd's >= 4.  This causes
rpc.gssd to fail when it's configured to use the gssproxy interposer
plugin (via "use-gss-proxy=1" in nfs.conf or GSS_USE_PROXY="yes" in the
environment) *and* libtirpc debugging is enabled (i.e. at least one
"-r" on the command line):

1. During startup if rpc debugging is enabled then libtirpc_set_debug()
   is called, which calls openlog() which consumes fd 3.
2. If the gssproxy interposer plugin is enabled then when
   gssd_check_mechs() is called, a socket is created (fd 4) and
   connected to /var/lib/gssproxy/default.sock.  The fd is stored
   internally in a struct gpm_ctx.
3. daemon_init() runs and closes all fd's >= 4.
4. event_init() runs which calls epoll_create() which returns an epoll
   fd of 4.
5. Later when handling an upcall, gssd calls gssd_acquire_krb5_cred()
   which winds up closing the gpm_ctx->fd which was 4.
6. event_dispatch() calls epoll_wait() with epfd=4, and -EBADF is
   returned.  gssd logs the message ""ERROR: event_dispatch() returned!"
   and exits.

The solution is to call daemon_init() earlier.

Signed-off-by: Scott Mayhew <smayhew@redhat.com>
---
 utils/gssd/gssd.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/utils/gssd/gssd.c b/utils/gssd/gssd.c
index 19ad4da..c38dedb 100644
--- a/utils/gssd/gssd.c
+++ b/utils/gssd/gssd.c
@@ -1020,11 +1020,11 @@ main(int argc, char *argv[])
 			    "support setting debug levels\n");
 #endif
 
+	daemon_init(fg);
+
 	if (gssd_check_mechs() != 0)
 		errx(1, "Problem with gssapi library");
 
-	daemon_init(fg);
-
 	event_init();
 
 	pipefs_dir = opendir(pipefs_path);
-- 
2.17.2