This is a note to let you know that I've just added the patch titled
nfsd4: don't allow owner override on 4.1 CLAIM_FH opens
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
nfsd4-don-t-allow-owner-override-on-4.1-claim_fh-opens.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9f415eb25574db4b73a9a712a4438e41dc284922 Mon Sep 17 00:00:00 2001
From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
Date: Fri, 3 May 2013 16:09:09 -0400
Subject: nfsd4: don't allow owner override on 4.1 CLAIM_FH opens
From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
commit 9f415eb25574db4b73a9a712a4438e41dc284922 upstream.
The Linux client is using CLAIM_FH to implement regular opens, not just
recovery cases, so it depends on the server to check permissions
correctly.
Therefore the owner override, which may make sense in the delegation
recovery case, isn't right in the CLAIM_FH case.
Symptoms: on a client with 49f9a0fafd844c32f2abada047c0b9a5ba0d6255
"NFSv4.1: Enable open-by-filehandle", Bryan noticed this:
touch test.txt
chmod 000 test.txt
echo test > test.txt
succeeding.
Reported-by: Bryan Schumaker <bjschuma@xxxxxxxxxx>
Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/nfsd/nfs4proc.c | 15 +++++++++++++--
1 file changed, 13 insertions(+), 2 deletions(-)
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -270,6 +270,7 @@ static __be32
do_open_fhandle(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nfsd4_open *open)
{
__be32 status;
+ int accmode = 0;
/* We don't know the target directory, and therefore can not
* set the change info
@@ -283,9 +284,19 @@ do_open_fhandle(struct svc_rqst *rqstp,
open->op_truncate = (open->op_iattr.ia_valid & ATTR_SIZE) &&
(open->op_iattr.ia_size == 0);
+ /*
+ * In the delegation case, the client is telling us about an
+ * open that it *already* performed locally, some time ago. We
+ * should let it succeed now if possible.
+ *
+ * In the case of a CLAIM_FH open, on the other hand, the client
+ * may be counting on us to enforce permissions (the Linux 4.1
+ * client uses this for normal opens, for example).
+ */
+ if (open->op_claim_type == NFS4_OPEN_CLAIM_DELEG_CUR_FH)
+ accmode = NFSD_MAY_OWNER_OVERRIDE;
- status = do_open_permission(rqstp, current_fh, open,
- NFSD_MAY_OWNER_OVERRIDE);
+ status = do_open_permission(rqstp, current_fh, open, accmode);
return status;
}
Patches currently in stable-queue which might be from bfields@xxxxxxxxxx are
queue-3.4/nfsd4-don-t-allow-owner-override-on-4.1-claim_fh-opens.patch
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