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	Diff line number	Diff line
		@@ -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

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