From 7fc90ec93a5eb71f4b08403baf5ba7176b3ec6b1 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Fri, 30 Jun 2006 01:56:14 -0700 Subject: [PATCH] [PATCH] knfsd: nfsd: call nfsd_setuser() on fh_compose(), fix nfsd4 permissions problem In the typical v2/v3 case the only new filehandles used as arguments to operations are filehandles taken directly off the wire, which don't get dentries until fh_verify() is called. But in v4 the filehandles that are arguments to operations were often created by previous operations (putrootfh, lookup, etc.) using fh_compose, which sets the dentry in the filehandle without calling nfsd_setuser(). This also means that, for example, if filesystem B is mounted on filesystem A, and filesystem A is exported without root-squashing, then a client can bypass the rootsquashing on B using a compound that starts at a filehandle in A, crosses into B using lookups, and then does stuff in B. Signed-off-by: J. Bruce Fields Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/nfsd/nfsfh.c | 15 ++++++++------- 1 file changed, 8 insertions(+), 7 deletions(-) diff --git a/fs/nfsd/nfsfh.c b/fs/nfsd/nfsfh.c index ca96ede30a1..ecc439d2565 100644 --- a/fs/nfsd/nfsfh.c +++ b/fs/nfsd/nfsfh.c @@ -187,13 +187,6 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access) goto out; } - /* Set user creds for this exportpoint */ - error = nfsd_setuser(rqstp, exp); - if (error) { - error = nfserrno(error); - goto out; - } - /* * Look up the dentry using the NFS file handle. */ @@ -251,6 +244,14 @@ fh_verify(struct svc_rqst *rqstp, struct svc_fh *fhp, int type, int access) } cache_get(&exp->h); + /* Set user creds for this exportpoint; necessary even in the "just + * checking" case because this may be a filehandle that was created by + * fh_compose, and that is about to be used in another nfsv4 compound + * operation */ + error = nfserrno(nfsd_setuser(rqstp, exp)); + if (error) + goto out; + error = nfsd_mode_check(rqstp, dentry->d_inode->i_mode, type); if (error) goto out; -- 2.41.1