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NFSD: Don't hold unrefcounted creds over call to nfsd_setuser()

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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>
This commit is contained in:
David Howells 2009-07-02 14:35:32 +01:00 committed by J. Bruce Fields
parent 28d0325ce6
commit 033a666ccb
1 changed files with 1 additions and 2 deletions
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3
fs/nfsd/vfs.c
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@ -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