NFSD: Don't hold unrefcounted creds over call to nfsd_setuser()
authorDavid Howells <dhowells@redhat.com>
Thu, 2 Jul 2009 13:35:32 +0000 (14:35 +0100)
committerJ. Bruce Fields <bfields@citi.umich.edu>
Fri, 3 Jul 2009 14:21:10 +0000 (10:21 -0400)
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 <dhowells@redhat.com>
Tested-and-Verified-By: Steve Dickson <steved@redhat.com>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
fs/nfsd/vfs.c

index 4145083dcf8817ed883652939cac1faa4dfd7cac..23341c1063bcd05fb2841dc6b49d0a91eef36293 100644 (file)
@@ -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