NFSD: Clear SECLABEL in the suppattr_exclcreat bitmap

[ Upstream commit 27d17641cacfedd816789b75d342430f6b912bd2 ]

>>From RFC 8881:

5.8.1.14. Attribute 75: suppattr_exclcreat

> The bit vector that would set all REQUIRED and RECOMMENDED
> attributes that are supported by the EXCLUSIVE4_1 method of file
> creation via the OPEN operation. The scope of this attribute
> applies to all objects with a matching fsid.

There's nothing in RFC 8881 that states that suppattr_exclcreat is
or is not allowed to contain bits for attributes that are clear in
the reported supported_attrs bitmask. But it doesn't make sense for
an NFS server to indicate that it /doesn't/ implement an attribute,
but then also indicate that clients /are/ allowed to set that
attribute using OPEN(create) with EXCLUSIVE4_1.

Ensure that the SECURITY_LABEL and ACL bits are not set in the
suppattr_exclcreat bitmask when they are also not set in the
supported_attrs bitmask.

Fixes: 8c18f2052e75 ("nfsd41: SUPPATTR_EXCLCREAT attribute")
Cc: stable@vger.kernel.org
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
[ Adjust context ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/nfsd/nfs4xdr.c b/fs/nfsd/nfs4xdr.c
index 57dc5493c860728a8245fd2a6cf570cc7eb3ef21..4253778a974774eab9a156614883aa1ade289dab 100644 (file)
--- a/fs/nfsd/nfs4xdr.c
+++ b/fs/nfsd/nfs4xdr.c
@@ -3408,6 +3408,11 @@ out_acl:
                u32 supp[3];
 
                memcpy(supp, nfsd_suppattrs[minorversion], sizeof(supp));
+               if (!IS_POSIXACL(d_inode(dentry)))
+                       supp[0] &= ~FATTR4_WORD0_ACL;
+               if (!contextsupport)
+                       supp[2] &= ~FATTR4_WORD2_SECURITY_LABEL;
+
                supp[0] &= NFSD_SUPPATTR_EXCLCREAT_WORD0;
                supp[1] &= NFSD_SUPPATTR_EXCLCREAT_WORD1;
                supp[2] &= NFSD_SUPPATTR_EXCLCREAT_WORD2;