From: Jeff Layton <jlayton@redhat.com>
Date: Thu, 17 Sep 2009 13:29:26 -0400
Subject: [nfs] nfsd4: idmap upcalls should use unsigned uid/gid
Message-id: 1253208566-9625-1-git-send-email-jlayton@redhat.com
O-Subject: [RHEL5.5 PATCH] BZ#519184: nfsd4: idmap upcalls should use unsigned uid and gid
Bugzilla: 519184
RH-Acked-by: Dean Nelson <dnelson@redhat.com>
RH-Acked-by: Steve Dickson <SteveD@redhat.com>

(backported from 0a725fc4d3bfc4734164863d6c50208b109ca5c7)

This problem fixes a rather nasty interaction between the kernel and
rpc.idmapd. rpc.idmapd expects that the kernel will send it unsigned
values for server-side upcalls. If it gets a negative value, it can
cause it to stop responding.

This is clearly also due to a bug in rpc.idmapd (bogus values shouldn't
cause it to stop responding), but the kernel should also provide the
correct info in the first place.

I've already fixed the bug in idmapd and pushed a patch upstream for
that. That portion of this problem is being tracked in bug 523285.

Original patch description follows:

-------------------------[snip]----------------------------

We shouldn't be using negative uid's and gid's in the idmap upcalls.

Signed-off-by: "J. Bruce Fields" <bfields@citi.umich.edu>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/nfsd/nfs4idmap.c b/fs/nfsd/nfs4idmap.c
index 7915039..d4e7760 100644
--- a/fs/nfsd/nfs4idmap.c
+++ b/fs/nfsd/nfs4idmap.c
@@ -140,7 +140,7 @@ idtoname_request(struct cache_detail *cd, struct cache_head *ch, char **bpp,
 	char idstr[11];
 
 	qword_add(bpp, blen, ent->authname);
-	snprintf(idstr, sizeof(idstr), "%d", ent->id);
+	snprintf(idstr, sizeof(idstr), "%u", ent->id);
 	qword_add(bpp, blen, ent->type == IDMAP_TYPE_GROUP ? "group" : "user");
 	qword_add(bpp, blen, idstr);
 
@@ -167,7 +167,7 @@ idtoname_show(struct seq_file *m, struct cache_detail *cd, struct cache_head *h)
 		return 0;
 	}
 	ent = container_of(h, struct ent, h);
-	seq_printf(m, "%s %s %d", ent->authname,
+	seq_printf(m, "%s %s %u", ent->authname,
 			ent->type == IDMAP_TYPE_GROUP ? "group" : "user",
 			ent->id);
 	if (test_bit(CACHE_VALID, &h->flags))
@@ -351,7 +351,7 @@ nametoid_show(struct seq_file *m, struct cache_detail *cd, struct cache_head *h)
 			ent->type == IDMAP_TYPE_GROUP ? "group" : "user",
 			ent->name);
 	if (test_bit(CACHE_VALID, &h->flags))
-		seq_printf(m, " %d", ent->id);
+		seq_printf(m, " %u", ent->id);
 	seq_printf(m, "\n");
 	return 0;
 }