Return-Path: Received: from linuxhacker.ru ([217.76.32.60]:41742 "EHLO fiona.linuxhacker.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751279AbcGODUi (ORCPT ); Thu, 14 Jul 2016 23:20:38 -0400 From: Oleg Drokin To: "J. Bruce Fields" , Jeff Layton Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org, Oleg Drokin Subject: [PATCH] nfsd: Make creates return EEXIST instead of EACCES Date: Thu, 14 Jul 2016 23:20:22 -0400 Message-Id: <1468552822-14175-1-git-send-email-green@linuxhacker.ru> Sender: linux-nfs-owner@vger.kernel.org List-ID: When doing a create (mkdir/mknod) on a name, it's worth checking the name exists first before returning EACCES in case the directory is not writeable by the user. This makes return values on the client more consistent regardless of whenever the entry there is cached in the local cache or not. Another positive side effect is certain programs only expect EEXIST in that case even despite POSIX allowing any valid error to be returned. Signed-off-by: Oleg Drokin --- fs/nfsd/nfs4proc.c | 6 +++++- fs/nfsd/vfs.c | 11 ++++++++++- 2 files changed, 15 insertions(+), 2 deletions(-) diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c index de1ff1d..0067520 100644 --- a/fs/nfsd/nfs4proc.c +++ b/fs/nfsd/nfs4proc.c @@ -605,8 +605,12 @@ nfsd4_create(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate, fh_init(&resfh, NFS4_FHSIZE); + /* + * We just check that parent is accessible here, nfsd_* do their + * own access permission checks + */ status = fh_verify(rqstp, &cstate->current_fh, S_IFDIR, - NFSD_MAY_CREATE); + NFSD_MAY_EXEC); if (status) return status; diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 6fbd81e..6a45ec6 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1161,7 +1161,11 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, if (isdotent(fname, flen)) goto out; - err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE); + /* + * Even though it is a create, first let's see if we are even allowed + * to peek inside the parent + */ + err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC); if (err) goto out; @@ -1211,6 +1215,11 @@ nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, goto out; } + /* Now let's see if we actually have permissions to create */ + err = nfsd_permission(rqstp, fhp->fh_export, dentry, NFSD_MAY_CREATE); + if (err) + goto out; + if (!(iap->ia_valid & ATTR_MODE)) iap->ia_mode = 0; iap->ia_mode = (iap->ia_mode & S_IALLUGO) | type; -- 2.7.4