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authorSachin Prabhu <sprabhu@redhat.com>2011-04-20 13:09:35 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2011-05-09 15:06:48 -0700
commit6f0a6240e8ce1659574e944eac04e871a9dc1fe7 (patch)
tree593d99950553e629afd0540628784c18c93826cd /fs
parent7b17624a7f6b41678d7452ebd5a525ddc3aaf3d3 (diff)
downloadlinux-linaro-android-6f0a6240e8ce1659574e944eac04e871a9dc1fe7.tar.gz
Open with O_CREAT flag set fails to open existing files on non writable directories
commit 1574dff8996ab1ed92c09012f8038b5566fce313 upstream. An open on a NFS4 share using the O_CREAT flag on an existing file for which we have permissions to open but contained in a directory with no write permissions will fail with EACCES. A tcpdump shows that the client had set the open mode to UNCHECKED which indicates that the file should be created if it doesn't exist and encountering an existing flag is not an error. Since in this case the file exists and can be opened by the user, the NFS server is wrong in attempting to check create permissions on the parent directory. The patch adds a conditional statement to check for create permissions only if the file doesn't exist. Signed-off-by: Sachin S. Prabhu <sprabhu@redhat.com> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'fs')
-rw-r--r--fs/nfsd/vfs.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index da1d9701f8e..435f407377b 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1363,7 +1363,7 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
goto out;
if (!(iap->ia_valid & ATTR_MODE))
iap->ia_mode = 0;
- err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
+ err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_EXEC);
if (err)
goto out;
@@ -1385,6 +1385,13 @@ nfsd_create_v3(struct svc_rqst *rqstp, struct svc_fh *fhp,
if (IS_ERR(dchild))
goto out_nfserr;
+ /* If file doesn't exist, check for permissions to create one */
+ if (!dchild->d_inode) {
+ err = fh_verify(rqstp, fhp, S_IFDIR, NFSD_MAY_CREATE);
+ if (err)
+ goto out;
+ }
+
err = fh_compose(resfhp, fhp->fh_export, dchild, fhp);
if (err)
goto out;