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[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 <bfields@citi.umich.edu>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
J. Bruce Fields 2006-06-30 01:56:14 -07:00 committed by Linus Torvalds
parent a8cddc5dfc
commit 7fc90ec93a
1 changed files with 8 additions and 7 deletions
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15
fs/nfsd/nfsfh.c
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@ -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;