From mboxrd@z Thu Jan 1 00:00:00 1970 From: "J. Bruce Fields" Subject: NFSD: Don't hold unrefcounted creds over call to nfsd_setuser() Date: Fri, 3 Jul 2009 11:47:57 -0400 Message-ID: <20090703154757.GG31538@fieldses.org> References: <20090703142250.GB31538@fieldses.org> <20090702203937.GA10504@fieldses.org> <20090702133532.28297.89635.stgit@warthog.procyon.org.uk> <575.1246570293@redhat.com> <20090702230955.GB12376@fieldses.org> <31545.1246632086@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: David Howells , steved@redhat.com, rasmus-tUP8e6pgWdNlY7y4Fx5NiA@public.gmane.org, linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org To: Linus Torvalds Return-path: Received: from 174-143-236-118.static.slicehost.net ([174.143.236.118]:44945 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756649AbZGCPsA (ORCPT ); Fri, 3 Jul 2009 11:48:00 -0400 In-Reply-To: <31545.1246632086@redhat.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: The following patch is appropriate for 2.6.31 (and stable), and is also available from git://linux-nfs.org/~bfields/linux.git for-2.6.31 --b. commit 033a666ccb842ab4134fcd0c861d5ba9f5d6bf3a Author: David Howells Date: Thu Jul 2 14:35:32 2009 +0100 NFSD: Don't hold unrefcounted creds over call to nfsd_setuser() nfsd_open() gets an unrefcounted pointer to the current process's effective credentials at the top of the function, then calls nfsd_setuser() via fh_verify() - which may replace and destroy the current process's effective credentials - and then passes the unrefcounted pointer to dentry_open() - but the credentials may have been destroyed by this point. Instead, the value from current_cred() should be passed directly to dentry_open() as one of its arguments, rather than being cached in a variable. Possibly fh_verify() should return the creds to use. This is a regression introduced by 745ca2475a6ac596e3d8d37c2759c0fbe2586227 "CRED: Pass credentials through dentry_open()". Signed-off-by: David Howells Tested-and-Verified-By: Steve Dickson Cc: stable@kernel.org Signed-off-by: J. Bruce Fields diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 4145083..23341c1 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -678,7 +678,6 @@ __be32 nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access, struct file **filp) { - const struct cred *cred = current_cred(); struct dentry *dentry; struct inode *inode; int flags = O_RDONLY|O_LARGEFILE; @@ -733,7 +732,7 @@ nfsd_open(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, vfs_dq_init(inode); } *filp = dentry_open(dget(dentry), mntget(fhp->fh_export->ex_path.mnt), - flags, cred); + flags, current_cred()); if (IS_ERR(*filp)) host_err = PTR_ERR(*filp); else