Commit 033a666c authored Jul 02, 2009 by David Howells Committed by J. Bruce Fields Jul 03, 2009

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
745ca247 "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>

parent 28d0325c

fs/nfsd/vfs.c

+1 −2

Original line number	Original line	Diff line number	Diff line
	@@ -678,7 +678,6 @@ __be32
	nfsd_open(struct svc_rqst rqstp, struct svc_fh fhp, int type,		nfsd_open(struct svc_rqst rqstp, struct svc_fh fhp, int type,
	int access, struct file **filp)		int access, struct file **filp)
	{		{
	const struct cred *cred = current_cred();
	struct dentry *dentry;		struct dentry *dentry;
	struct inode *inode;		struct inode *inode;
	int flags = O_RDONLY\|O_LARGEFILE;		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);		vfs_dq_init(inode);
	}		}
	*filp = dentry_open(dget(dentry), mntget(fhp->fh_export->ex_path.mnt),		*filp = dentry_open(dget(dentry), mntget(fhp->fh_export->ex_path.mnt),
	flags, cred);		flags, current_cred());
	if (IS_ERR(*filp))		if (IS_ERR(*filp))
	host_err = PTR_ERR(*filp);		host_err = PTR_ERR(*filp);
	else		else