From f9b9fbb5d3580dfb8cceedeb972e03069a1d7b8f Mon Sep 17 00:00:00 2001
From: Jeremy Allison <jra@samba.org>
Date: Thu, 19 Feb 2015 09:26:18 -0800
Subject: [PATCH] s3: smbd: Add new no_new_files VFS module.

Provides a read-only filesystem on which files can still be deleted.

Signed-off-by: Jeremy Allison <jra@samba.org>
Extra config patches added by: Jeffrey Kardatzke <jkardatzke@google.com>
---
 source3/Makefile.in                |   5 +
 source3/configure                  |  36 ++++++++
 source3/configure.in               |   2 +
 source3/include/config.h.in        |   3 +
 source3/modules/vfs_no_new_files.c | 181 +++++++++++++++++++++++++++++++++++++
 source3/modules/wscript_build      |   8 ++
 source3/wscript                    |   2 +-
 7 files changed, 236 insertions(+), 1 deletion(-)
 create mode 100644 source3/modules/vfs_no_new_files.c

diff --git a/source3/Makefile.in b/source3/Makefile.in
index 9e8e03d..67274fa 100644
--- a/source3/Makefile.in
+++ b/source3/Makefile.in
@@ -848,6 +848,7 @@ VFS_SCANNEDONLY_OBJ = modules/vfs_scannedonly.o
 VFS_CROSSRENAME_OBJ = modules/vfs_crossrename.o
 VFS_LINUX_XFS_SGID_OBJ = modules/vfs_linux_xfs_sgid.o
 VFS_TIME_AUDIT_OBJ = modules/vfs_time_audit.o
+VFS_NO_NEW_FILES_OBJ = modules/vfs_no_new_files.o
 
 PAM_ERRORS_OBJ = ../libcli/auth/pam_errors.o
 PLAINTEXT_AUTH_OBJ = auth/pampass.o auth/pass_check.o $(PAM_ERRORS_OBJ)
@@ -3191,6 +3192,10 @@ bin/time_audit.@SHLIBEXT@: $(BINARY_PREREQS) $(VFS_TIME_AUDIT_OBJ)
 	@echo "Building plugin $@"
 	@$(SHLD_MODULE) $(VFS_TIME_AUDIT_OBJ)
 
+bin/no_new_files.@SHLIBEXT@: $(BINARY_PREREQS) $(VFS_NO_NEW_FILES_OBJ)
+	@echo "Building plugin $@"
+	@$(SHLD_MODULE) $(VFS_NO_NEW_FILES_OBJ)
+
 #########################################################
 ## IdMap NSS plugins
 
diff --git a/source3/configure b/source3/configure
index 5ab687b..ced1973 100755
--- a/source3/configure
+++ b/source3/configure
@@ -8430,6 +8430,7 @@ default_shared_modules="$default_shared_modules vfs_crossrename"
 default_shared_modules="$default_shared_modules vfs_linux_xfs_sgid"
 default_shared_modules="$default_shared_modules vfs_time_audit"
 default_shared_modules="$default_shared_modules idmap_autorid"
+default_shared_modules="$default_shared_modules vfs_no_new_files"
 
 if test "x$developer" = xyes; then
    default_static_modules="$default_static_modules rpc_rpcecho pdb_ads"
@@ -40125,6 +40126,41 @@ $as_echo "not" >&6; }
 	fi
 
 
+	{ $as_echo "$as_me:${as_lineno-$LINENO}: checking how to build vfs_no_new_files" >&5
+$as_echo_n "checking how to build vfs_no_new_files... " >&6; }
+	if test "$MODULE_vfs_no_new_files"; then
+		DEST=$MODULE_vfs_no_new_files
+	elif test "$MODULE_vfs" -a "$MODULE_DEFAULT_vfs_no_new_files"; then
+		DEST=$MODULE_vfs
+	else
+		DEST=$MODULE_DEFAULT_vfs_no_new_files
+	fi
+
+	if test x"$DEST" = xSHARED; then
+
+$as_echo "#define vfs_no_new_files_init init_samba_module" >>confdefs.h
+
+		VFS_MODULES="$VFS_MODULES "bin/no_new_files.$SHLIBEXT""
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: shared" >&5
+$as_echo "shared" >&6; }
+
+		string_shared_modules="$string_shared_modules vfs_no_new_files"
+	elif test x"$DEST" = xSTATIC; then
+		init_static_modules_vfs="$init_static_modules_vfs  vfs_no_new_files_init();"
+		decl_static_modules_vfs="$decl_static_modules_vfs extern NTSTATUS vfs_no_new_files_init(void);"
+		string_static_modules="$string_static_modules vfs_no_new_files"
+		VFS_STATIC="$VFS_STATIC \$(VFS_NO_NEW_FILES_OBJ)"
+
+
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: static" >&5
+$as_echo "static" >&6; }
+	else
+	    string_ignored_modules="$string_ignored_modules vfs_no_new_files"
+		{ $as_echo "$as_me:${as_lineno-$LINENO}: result: not" >&5
+$as_echo "not" >&6; }
+	fi
+
+
 
 
 
diff --git a/source3/configure.in b/source3/configure.in
index 42c23e3..6b0b859 100644
--- a/source3/configure.in
+++ b/source3/configure.in
@@ -463,6 +463,7 @@ default_shared_modules="$default_shared_modules vfs_crossrename"
 default_shared_modules="$default_shared_modules vfs_linux_xfs_sgid"
 default_shared_modules="$default_shared_modules vfs_time_audit"
 default_shared_modules="$default_shared_modules idmap_autorid"
+default_shared_modules="$default_shared_modules vfs_no_new_files"
 
 if test "x$developer" = xyes; then
    default_static_modules="$default_static_modules rpc_rpcecho pdb_ads"
@@ -7007,6 +7008,7 @@ SMB_MODULE(vfs_scannedonly, \$(VFS_SCANNEDONLY_OBJ), "bin/scannedonly.$SHLIBEXT"
 SMB_MODULE(vfs_crossrename, \$(VFS_CROSSRENAME_OBJ), "bin/crossrename.$SHLIBEXT", VFS)
 SMB_MODULE(vfs_linux_xfs_sgid, \$(VFS_LINUX_XFS_SGID_OBJ), "bin/linux_xfs_sgid.$SHLIBEXT", VFS)
 SMB_MODULE(vfs_time_audit, \$(VFS_TIME_AUDIT_OBJ), "bin/time_audit.$SHLIBEXT", VFS)
+SMB_MODULE(vfs_no_new_files, \$(VFS_NO_NEW_FILES_OBJ), "bin/no_new_files.$SHLIBEXT", VFS)
 
 SMB_SUBSYSTEM(VFS,smbd/vfs.o)

diff --git a/source3/include/config.in.h b/source3/include/config.in.h
index 63f0cf0..5b6b9b3 100644
--- a/source3/include/config.h.in
+++ b/source3/include/config.h.in
@@ -3473,6 +3473,9 @@
 /* Whether to build vfs_notify_fam as shared module */
 #undef vfs_notify_fam_init

+/* Whether to build vfs_no_new_files as shared module */
+#undef vfs_no_new_files_init
+
 /* Whether to build vfs_onefs as shared module */
 #undef vfs_onefs_init

diff --git a/source3/modules/vfs_no_new_files.c b/source3/modules/vfs_no_new_files.c
new file mode 100644
index 0000000..3a73363
--- /dev/null
+++ b/source3/modules/vfs_no_new_files.c
@@ -0,0 +1,181 @@
+/*
+ * Copyright (c) Jeremy Allison 2015.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "includes.h"
+#include "system/filesys.h"
+#include "smbd/smbd.h"
+
+static int nnf_mkdir(vfs_handle_struct *handle, const char *path, mode_t mode)
+{
+	errno = EACCES;
+	return -1;
+}
+
+static int nnf_open_fn(vfs_handle_struct *handle,
+			struct smb_filename *smb_fname,
+			files_struct *fsp,
+			int flags,
+			mode_t mode)
+{
+	if (flags & O_CREAT) {
+		errno = EACCES;
+		return -1;
+	}
+	return SMB_VFS_NEXT_OPEN(handle, smb_fname, fsp, flags, mode);
+}
+
+static NTSTATUS nnf_create_file(vfs_handle_struct *handle,
+			struct smb_request *req,
+			uint16_t root_dir_fid,
+			struct smb_filename *smb_fname,
+			uint32_t access_mask,
+			uint32_t share_access,
+			uint32_t create_disposition,
+			uint32_t create_options,
+			uint32_t file_attributes,
+			uint32_t oplock_request,
+			uint64_t allocation_size,
+			uint32_t private_flags,
+			struct security_descriptor *sd,
+			struct ea_list *ea_list,
+			files_struct **result_fsp,
+			int *pinfo)
+{
+	switch (create_disposition) {
+	case FILE_OPEN:
+	case FILE_OVERWRITE:
+		break;
+	default:
+		errno = EACCES;
+		return NT_STATUS_ACCESS_DENIED;
+	}
+
+	return SMB_VFS_NEXT_CREATE_FILE(
+		handle,                                 /* handle */
+		req,                                    /* req */
+		root_dir_fid,                           /* root_dir_fid */
+		smb_fname,                              /* fname */
+		access_mask,                            /* access_mask */
+		share_access,                           /* share_access */
+		create_disposition,                     /* create_disposition*/
+		create_options,                         /* create_options */
+		file_attributes,                        /* file_attributes */
+		oplock_request,                         /* oplock_request */
+		allocation_size,                        /* allocation_size */
+		private_flags,
+		sd,                                     /* sd */
+		ea_list,                                /* ea_list */
+		result_fsp,                             /* result */
+		pinfo);                                 /* pinfo */
+}
+
+static int nnf_rename(vfs_handle_struct *handle,
+			const struct smb_filename *smb_fname_src,
+			const struct smb_filename *smb_fname_dst)
+{
+	errno = EACCES;
+	return -1;
+}
+
+static ssize_t nnf_pwrite(vfs_handle_struct *handle,
+			files_struct *fsp,
+			const void *data,
+			size_t n,
+			SMB_OFF_T offset)
+{
+	errno = EACCES;
+	return -1;
+}
+
+static ssize_t nnf_write(vfs_handle_struct *handle,
+			files_struct *fsp,
+			const void *data,
+			size_t n)
+{
+	errno = EACCES;
+	return -1;
+}
+
+static int nnf_fallocate(vfs_handle_struct *handle,
+			files_struct *fsp,
+			enum vfs_fallocate_mode mode,
+			SMB_OFF_T offset,
+			SMB_OFF_T len)
+{
+	if (mode == VFS_FALLOCATE_EXTEND_SIZE) {
+		errno = ENOSPC;
+		return -1;
+	}
+	return SMB_VFS_NEXT_FALLOCATE(handle, fsp, mode, offset, len);
+}
+
+static int nnf_symlink(vfs_handle_struct *handle,
+			const char *oldpath,
+			const char *newpath)
+{
+	errno = EACCES;
+	return -1;
+}
+
+static int nnf_link(vfs_handle_struct *handle,
+			const char *oldpath,
+			const char *newpath)
+{
+	errno = EACCES;
+	return -1;
+}
+
+static int nnf_mknod(vfs_handle_struct *handle,
+			const char *pathname,
+			mode_t mode,
+			SMB_DEV_T dev)
+{
+	errno = EACCES;
+	return -1;
+}
+
+static int nnf_aio_write(struct vfs_handle_struct *handle,
+			struct files_struct *fsp,
+			SMB_STRUCT_AIOCB *aiocb)
+{
+	errno = EACCES;
+	return -1;
+}
+
+static struct vfs_fn_pointers vfs_no_new_files_fns = {
+	.mkdir = nnf_mkdir,
+	.open_fn = nnf_open_fn,
+	.create_file = nnf_create_file,
+	.rename = nnf_rename,
+	.pwrite = nnf_pwrite,
+	.write = nnf_write,
+	.fallocate = nnf_fallocate,
+	.symlink = nnf_symlink,
+	.link = nnf_link,
+	.mknod = nnf_mknod,
+	.aio_write = nnf_aio_write
+};
+
+/*******************************************************************
+ Module initialization boilerplate.
+*******************************************************************/
+
+NTSTATUS vfs_no_new_files_init(void)
+{
+	return smb_register_vfs(SMB_VFS_INTERFACE_VERSION, "no_new_files",
+				&vfs_no_new_files_fns);
+}
diff --git a/source3/modules/wscript_build b/source3/modules/wscript_build
index ff7163f..12aa86e 100644
--- a/source3/modules/wscript_build
+++ b/source3/modules/wscript_build
@@ -50,6 +50,7 @@ VFS_SCANNEDONLY_SRC = 'vfs_scannedonly.c'
 VFS_CROSSRENAME_SRC = 'vfs_crossrename.c'
 VFS_LINUX_XFS_SGID_SRC = 'vfs_linux_xfs_sgid.c'
 VFS_TIME_AUDIT_SRC = 'vfs_time_audit.c'
+VFS_NO_NEW_FILES_SRC = 'vfs_no_new_files.c'
 
 
 bld.SAMBA3_SUBSYSTEM('NFS4_ACLS',
@@ -408,6 +409,13 @@ bld.SAMBA3_MODULE('vfs_time_audit',
                  internal_module=bld.SAMBA3_IS_STATIC_MODULE('vfs_time_audit'),
                  enabled=bld.SAMBA3_IS_ENABLED_MODULE('vfs_time_audit'))
 
+bld.SAMBA3_MODULE('vfs_no_new_files',
+                 subsystem='vfs',
+                 source=VFS_NO_NEW_FILES_SRC,
+                 init_function='',
+                 internal_module=bld.SAMBA3_IS_STATIC_MODULE('vfs_no_new_files'),
+                 enabled=bld.SAMBA3_IS_ENABLED_MODULE('vfs_no_new_files'))
+
 
 
 CHARSET_WEIRD_SRC = 'weird.c'
diff --git a/source3/wscript b/source3/wscript
index bcc6ce1..afbc358 100644
--- a/source3/wscript
+++ b/source3/wscript
@@ -1764,7 +1764,7 @@ main() {
                                       vfs_streams_xattr vfs_streams_depot vfs_acl_xattr vfs_acl_tdb
                                       vfs_smb_traffic_analyzer vfs_preopen vfs_catia vfs_scannedonly
                                       vfs_crossrename vfs_linux_xfs_sgid
-                                      vfs_time_audit idmap_autorid''')
+                                      vfs_time_audit vfs_no_new_files idmap_autorid''')
 
     if Options.options.developer:
         default_static_modules.extend(TO_LIST('pdb_ads auth_netlogond'))
-- 
1.9.1