retrieving CIFS ACLs when mounted with SMB2 fails dropping session

The get/set ACL xattr support for CIFS ACLs attempts to send old
cifs dialect protocol requests even when mounted with SMB2 or later
dialects. Sending cifs requests on an smb2 session causes problems -
the server drops the session due to the illegal request.

This patch makes CIFS ACL operations protocol specific to fix that.

Attempting to query/set CIFS ACLs for SMB2 will now return
EOPNOTSUPP (until we add worker routines for sending query
ACL requests via SMB2) instead of sending invalid (cifs)
requests.

A separate followon patch will be needed to fix cifs_acl_to_fattr
(which takes a cifs specific u16 fid so can't be abstracted
to work with SMB2 until that is changed) and will be needed
to fix mount problems when "cifsacl" is specified on mount
with e.g. vers=2.1

Signed-off-by: Steve French <smfrench@gmail.com>
Reviewed-by: Shirish Pargaonkar <spargaonkar@suse.com>
CC: Stable <stable@kernel.org>
diff --git a/fs/cifs/cifsacl.c b/fs/cifs/cifsacl.c
index 8f9b4f7..c819b0b 100644
--- a/fs/cifs/cifsacl.c
+++ b/fs/cifs/cifsacl.c
@@ -1043,15 +1043,30 @@
 	__u32 secdesclen = 0;
 	struct cifs_ntsd *pntsd = NULL; /* acl obtained from server */
 	struct cifs_ntsd *pnntsd = NULL; /* modified acl to be sent to server */
+	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct tcon_link *tlink = cifs_sb_tlink(cifs_sb);
+	struct cifs_tcon *tcon;
+
+	if (IS_ERR(tlink))
+		return PTR_ERR(tlink);
+	tcon = tlink_tcon(tlink);
 
 	cifs_dbg(NOISY, "set ACL from mode for %s\n", path);
 
 	/* Get the security descriptor */
-	pntsd = get_cifs_acl(CIFS_SB(inode->i_sb), inode, path, &secdesclen);
+
+	if (tcon->ses->server->ops->get_acl == NULL) {
+		cifs_put_tlink(tlink);
+		return -EOPNOTSUPP;
+	}
+
+	pntsd = tcon->ses->server->ops->get_acl(cifs_sb, inode, path,
+						&secdesclen);
 	if (IS_ERR(pntsd)) {
 		rc = PTR_ERR(pntsd);
 		cifs_dbg(VFS, "%s: error %d getting sec desc\n", __func__, rc);
-		goto out;
+		cifs_put_tlink(tlink);
+		return rc;
 	}
 
 	/*
@@ -1064,6 +1079,7 @@
 	pnntsd = kmalloc(secdesclen, GFP_KERNEL);
 	if (!pnntsd) {
 		kfree(pntsd);
+		cifs_put_tlink(tlink);
 		return -ENOMEM;
 	}
 
@@ -1072,14 +1088,18 @@
 
 	cifs_dbg(NOISY, "build_sec_desc rc: %d\n", rc);
 
+	if (tcon->ses->server->ops->set_acl == NULL)
+		rc = -EOPNOTSUPP;
+
 	if (!rc) {
 		/* Set the security descriptor */
-		rc = set_cifs_acl(pnntsd, secdesclen, inode, path, aclflag);
+		rc = tcon->ses->server->ops->set_acl(pnntsd, secdesclen, inode,
+						     path, aclflag);
 		cifs_dbg(NOISY, "set_cifs_acl rc: %d\n", rc);
 	}
+	cifs_put_tlink(tlink);
 
 	kfree(pnntsd);
 	kfree(pntsd);
-out:
 	return rc;
 }
diff --git a/fs/cifs/cifsglob.h b/fs/cifs/cifsglob.h
index a245d18..615e35a 100644
--- a/fs/cifs/cifsglob.h
+++ b/fs/cifs/cifsglob.h
@@ -395,6 +395,10 @@
 	int (*set_EA)(const unsigned int, struct cifs_tcon *, const char *,
 			const char *, const void *, const __u16,
 			const struct nls_table *, int);
+	struct cifs_ntsd * (*get_acl)(struct cifs_sb_info *, struct inode *,
+			const char *, u32 *);
+	int (*set_acl)(struct cifs_ntsd *, __u32, struct inode *, const char *,
+			int);
 };
 
 struct smb_version_values {
diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c
index 3e4ff79..bfd66d8 100644
--- a/fs/cifs/smb1ops.c
+++ b/fs/cifs/smb1ops.c
@@ -1071,6 +1071,10 @@
 	.query_all_EAs = CIFSSMBQAllEAs,
 	.set_EA = CIFSSMBSetEA,
 #endif /* CIFS_XATTR */
+#ifdef CONFIG_CIFS_ACL
+	.get_acl = get_cifs_acl,
+	.set_acl = set_cifs_acl,
+#endif /* CIFS_ACL */
 };
 
 struct smb_version_values smb1_values = {
diff --git a/fs/cifs/xattr.c b/fs/cifs/xattr.c
index 95c43bb..5ac836a 100644
--- a/fs/cifs/xattr.c
+++ b/fs/cifs/xattr.c
@@ -176,8 +176,12 @@
 			rc = -ENOMEM;
 		} else {
 			memcpy(pacl, ea_value, value_size);
-			rc = set_cifs_acl(pacl, value_size,
-				direntry->d_inode, full_path, CIFS_ACL_DACL);
+			if (pTcon->ses->server->ops->set_acl)
+				rc = pTcon->ses->server->ops->set_acl(pacl,
+						value_size, direntry->d_inode,
+						full_path, CIFS_ACL_DACL);
+			else
+				rc = -EOPNOTSUPP;
 			if (rc == 0) /* force revalidate of the inode */
 				CIFS_I(direntry->d_inode)->time = 0;
 			kfree(pacl);
@@ -323,8 +327,11 @@
 			u32 acllen;
 			struct cifs_ntsd *pacl;
 
-			pacl = get_cifs_acl(cifs_sb, direntry->d_inode,
-						full_path, &acllen);
+			if (pTcon->ses->server->ops->get_acl == NULL)
+				goto get_ea_exit; /* rc already EOPNOTSUPP */
+
+			pacl = pTcon->ses->server->ops->get_acl(cifs_sb,
+					direntry->d_inode, full_path, &acllen);
 			if (IS_ERR(pacl)) {
 				rc = PTR_ERR(pacl);
 				cifs_dbg(VFS, "%s: error %zd getting sec desc\n",