linux-kernel - [PATCH 4.1 84/84] nfsd: do nfs4_check_fh in nfs4_check_file instead of nfs4_check

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Message-Id: <20150814174212.748128854@linuxfoundation.org>
Date:	Fri, 14 Aug 2015 10:42:52 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Jeff Layton <jeff.layton@...marydata.com>,
	"J. Bruce Fields" <bfields@...hat.com>
Subject: [PATCH 4.1 84/84] nfsd: do nfs4_check_fh in nfs4_check_file instead of nfs4_check_olstateid

4.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jeff Layton <jlayton@...chiereds.net>

commit 8fcd461db7c09337b6d2e22d25eb411123f379e3 upstream.

Currently, preprocess_stateid_op calls nfs4_check_olstateid which
verifies that the open stateid corresponds to the current filehandle in the
call by calling nfs4_check_fh.

If the stateid is a NFS4_DELEG_STID however, then no such check is done.
This could cause incorrect enforcement of permissions, because the
nfsd_permission() call in nfs4_check_file uses current the current
filehandle, but any subsequent IO operation will use the file descriptor
in the stateid.

Move the call to nfs4_check_fh into nfs4_check_file instead so that it
can be done for all stateid types.

Signed-off-by: Jeff Layton <jeff.layton@...marydata.com>
[bfields: moved fh check to avoid NULL deref in special stateid case]
Signed-off-by: J. Bruce Fields <bfields@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/nfsd/nfs4state.c |   12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -4397,9 +4397,9 @@ laundromat_main(struct work_struct *laun
 	queue_delayed_work(laundry_wq, &nn->laundromat_work, t*HZ);
 }
 
-static inline __be32 nfs4_check_fh(struct svc_fh *fhp, struct nfs4_ol_stateid *stp)
+static inline __be32 nfs4_check_fh(struct svc_fh *fhp, struct nfs4_stid *stp)
 {
-	if (!fh_match(&fhp->fh_handle, &stp->st_stid.sc_file->fi_fhandle))
+	if (!fh_match(&fhp->fh_handle, &stp->sc_file->fi_fhandle))
 		return nfserr_bad_stateid;
 	return nfs_ok;
 }
@@ -4599,9 +4599,6 @@ nfs4_check_olstateid(struct svc_fh *fhp,
 {
 	__be32 status;
 
-	status = nfs4_check_fh(fhp, ols);
-	if (status)
-		return status;
 	status = nfsd4_check_openowner_confirmed(ols);
 	if (status)
 		return status;
@@ -4652,6 +4649,9 @@ nfs4_preprocess_stateid_op(struct net *n
 		status = nfserr_bad_stateid;
 		break;
 	}
+	if (status)
+		goto out;
+	status = nfs4_check_fh(fhp, s);
 
 	if (!status && filpp) {
 		*filpp = nfs4_find_file(s, flags);
@@ -4761,7 +4761,7 @@ static __be32 nfs4_seqid_op_checks(struc
 	status = check_stateid_generation(stateid, &stp->st_stid.sc_stateid, nfsd4_has_session(cstate));
 	if (status)
 		return status;
-	return nfs4_check_fh(current_fh, stp);
+	return nfs4_check_fh(current_fh, &stp->st_stid);
 }
 
 /* 


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