[3.11.y.z extended stable] Patch "nfsd: return better errors to exportfs" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    nfsd: return better errors to exportfs

to the linux-3.11.y-queue branch of the 3.11.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.11.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.11.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From c58a04131ec8971789b308fa451d22b9265993fa Mon Sep 17 00:00:00 2001
From: "J. Bruce Fields" <bfields at redhat.com>
Date: Fri, 13 Sep 2013 11:08:45 -0400
Subject: nfsd: return better errors to exportfs

commit 427d6c6646d868fbd3094e7e2e1644d480cd9204 upstream.

Someone noticed exportfs happily accepted exports that would later be
rejected when mountd tried to give them to the kernel.  Fix this.

This is a regression from 4c1e1b34d5c800ad3ac9a7e2805b0bea70ad2278
"nfsd: Store ex_anon_uid and ex_anon_gid as kuids and kgids".

Cc: "Eric W. Biederman" <ebiederm at xmission.com>
Reported-by: Yin.JianHong <jiyin at redhat.com>
Signed-off-by: J. Bruce Fields <bfields at redhat.com>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 fs/nfsd/export.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index 5f38ea3..af51cf9 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -536,16 +536,12 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
 		if (err)
 			goto out3;
 		exp.ex_anon_uid= make_kuid(&init_user_ns, an_int);
-		if (!uid_valid(exp.ex_anon_uid))
-			goto out3;

 		/* anon gid */
 		err = get_int(&mesg, &an_int);
 		if (err)
 			goto out3;
 		exp.ex_anon_gid= make_kgid(&init_user_ns, an_int);
-		if (!gid_valid(exp.ex_anon_gid))
-			goto out3;

 		/* fsid */
 		err = get_int(&mesg, &an_int);
@@ -583,6 +579,17 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
 				   exp.ex_uuid);
 		if (err)
 			goto out4;
+		/*
+		 * For some reason exportfs has been passing down an
+		 * invalid (-1) uid & gid on the "dummy" export which it
+		 * uses to test export support.  To make sure exportfs
+		 * sees errors from check_export we therefore need to
+		 * delay these checks till after check_export:
+		 */
+		if (!uid_valid(exp.ex_anon_uid))
+			goto out4;
+		if (!gid_valid(exp.ex_anon_gid))
+			goto out4;
 	}

 	expp = svc_export_lookup(&exp);
--
1.8.3.2