implement one lua state per connectionHEADmaster

This allows you load various modules into a server lua state and give
a performance boost when calling the privileged functions

22 files changed, 483 insertions, 155 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..61f6f65
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,7 @@
+SUBDIRS=server client
+
+
+all:
+	for dir in $(SUBDIRS); do \
+		$(MAKE) -C $$dir || exit 1; \
+	done
diff --git a/bin/conn.h b/bin/conn.h
deleted file mode 100644
index f5b33a9..0000000
--- a/bin/conn.h
+++ /dev/null
@@ -1,8 +0,0 @@
-#ifndef CONN_H
-#define CONN_H
-
-#include <ev.h>
-
-int conn_init(struct ev_loop *loop, const char *socket_path);
-
-#endif
diff --git a/bin/lua-privsep.h b/bin/lua-privsep.h
deleted file mode 100644
index 9b7e219..0000000
--- a/bin/lua-privsep.h
+++ /dev/null
@@ -1,6 +0,0 @@
-#ifndef LUA_PRIVSEP_H
-#define LUA_PRIVSEP_H
-
-int call_lua(int fd, const char *msg, size_t msglen);
-
-#endif
diff --git a/client/Makefile b/client/Makefile
new file mode 100644
index 0000000..b318964
--- /dev/null
+++ b/client/Makefile
@@ -0,0 +1,23 @@
+
+COMPILE_PROG = $(CC) $(CFLAGS) $(LDFLAGS) -o $@ $($@-objs) $($@-libs)
+COMPILE_LUALIB = $(CC) $(CFLAGS) $(LDFLAGS) -shared -o $@ $($@-objs) $($@-libs)
+
+CFLAGS ?= -g
+
+PKGCONF ?= pkg-config
+
+LUA_PKG ?= lua
+LUA_CFLAGS := $(shell $(PKGCONF) --cflags $(LUA_PKG))
+LUA_LIBS := $(shell $(PKGCONF) --libs $(LUA_PKG))
+
+client.so-objs = lua-client.o
+client.so-libs = $(LUA_LIBS)
+
+all: client.so
+
+client.so: $(client.so-objs)
+	$(COMPILE_LUALIB)
+
+clean:
+	rm -f client.so
+
diff --git a/client/client.so b/client/client.so
new file mode 100755
index 0000000..a6567bd
--- /dev/null
+++ b/client/client.so
diff --git a/bin/list.h b/client/list.h
index 1fca5e7..1fca5e7 100644
--- a/bin/list.h
+++ b/client/list.h
diff --git a/client/lua-client.c b/client/lua-client.c
new file mode 100644
index 0000000..ca4365a
--- /dev/null
+++ b/client/lua-client.c
@@ -0,0 +1,112 @@
+
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <unistd.h>
+
+#include <lua.h>
+#include <lualib.h>
+#include <lauxlib.h>
+
+#define LIBNAME "client"
+
+#ifndef VERSION
+#define VERSION "(unknown)"
+#endif
+
+#ifndef DEFAULT_SOCKET_PATH
+#define DEFAULT_SOCKET_PATH "/var/run/privsep/root.sock"
+#endif
+
+#define BUFSIZE 32768
+
+static int pusherror(lua_State *L, const char *info)
+{
+	lua_pushnil(L);
+	if (info == NULL)
+		lua_pushstring(L, strerror(errno));
+	else
+		lua_pushfstring(L, "%s: %s", info, strerror(errno));
+	lua_pushinteger(L, errno);
+	return 3;
+}
+
+static int Pconnect(lua_State *L)
+{
+	const char *socket_path = luaL_optstring(L, 1, DEFAULT_SOCKET_PATH);
+	struct sockaddr_un sun;
+	int fd, ret;
+
+	memset(&sun, 0, sizeof(sun));
+	sun.sun_family = AF_UNIX;
+	strncpy(sun.sun_path, socket_path, sizeof(sun.sun_path));
+
+	fd = socket(AF_UNIX, SOCK_STREAM, 0);
+	if (fd < 0)
+		return pusherror(L, "socket");
+
+	if (connect(fd, (struct sockaddr *) &sun, sizeof(sun)) < 0) {
+		ret = pusherror(L, socket_path);
+		goto close_err;
+	}
+
+	lua_pushinteger(L, fd);
+	return 1;
+
+close_err:
+	close(fd);
+	return ret;
+}
+
+static int push_err_or_int(lua_State *L, ssize_t n)
+{
+	if (n < 0)
+		return pusherror(L, NULL);
+	lua_pushinteger(L, n);
+	return 1;
+}
+
+static int Pwrite(lua_State *L)
+{
+	int fd = luaL_checkinteger(L, 1);
+	size_t len = 0;
+	const char *msg = luaL_checklstring(L, 2, &len);
+	return push_err_or_int(L, write(fd, msg, len));
+}
+
+static int Precv(lua_State *L)
+{
+	int fd = luaL_checkinteger(L, 1);
+	static char buf[BUFSIZE];
+	ssize_t n = recv(fd, buf, sizeof(buf), 0);
+	if (n < 0)
+		return pusherror(L, NULL);
+	lua_pushlstring(L, buf, n);
+	return 1;
+}
+
+static int Pclose(lua_State *L)
+{
+	int fd = luaL_checkinteger(L, 1);
+	return push_err_or_int(L, close(fd));
+}
+
+static const luaL_reg reg_client_methods[] = {
+	{"connect",	Pconnect},
+	{"write",	Pwrite},
+	{"recv",	Precv},
+	{"close",	Pclose},
+	{NULL,	NULL},
+};
+
+
+LUALIB_API int luaopen_client(lua_State *L)
+{
+	luaL_register(L, LIBNAME, reg_client_methods);
+	lua_pushliteral(L, "version");
+	lua_pushliteral(L, VERSION);
+	lua_settable(L, -3);
+	return 1;
+}
diff --git a/client/modules b/client/modules
new file mode 120000
index 0000000..464b823
--- /dev/null
+++ b/client/modules
@@ -0,0 +1 @@
+../modules
\ No newline at end of file
diff --git a/client/privsep.lua b/client/privsep.lua
new file mode 100644
index 0000000..432f472
--- /dev/null
+++ b/client/privsep.lua
@@ -0,0 +1,57 @@
+
+ipcmsg = require("cmsgpack")
+ipcmsg.encode = ipcmsg.pack
+ipcmsg.decode = ipcmsg.unpack
+
+client = require("client")
+
+local ml = require("ml")
+
+local modules_path = "./modules"
+
+local privsep = {}
+
+local function call(conn, req)
+	local n = client.write(conn.fd, ipcmsg.encode(req))
+	retmsg, errmsg = client.recv(conn.fd)
+	if retmsg then
+		local data = ipcmsg.decode(retmsg)
+		return unpack(data.result or {})
+	end
+	return nil, errmsg
+end
+
+local function wrap(conn, modname)
+	local mod = dofile(modules_path.."/"..modname..".lua")
+	local f = {}
+	local i = #conn.mods + 1
+	local ret = conn:call{ type = "load", modidx = i,
+		                    modname = modname }
+	if ret == nil then
+		return nil
+	end
+	for k,v in pairs(mod) do
+		f[k] = function(...)
+			return conn:call{ type = "call", modidx = i,
+					       func = k, args = {...}}
+		end
+	end
+	conn[i] = f
+	return f
+end
+
+function privsep.connect(token)
+	return {
+		["fd"] = client.connect(),
+		["call"] = call,
+		["wrap"] = wrap,
+		["close"] = function(self)
+				return client.close(self.fd)
+			end,
+		["mods"] = {},
+	}
+end
+
+
+return privsep
+
diff --git a/client/test.lua b/client/test.lua
new file mode 100644
index 0000000..38e7429
--- /dev/null
+++ b/client/test.lua
@@ -0,0 +1,20 @@
+
+ps = require("privsep")
+
+c = ps.connect()
+
+mymod = c:wrap("mymod")
+
+if mymod == nil then
+	print("mymod is nil")
+end
+
+pos = require("posix")
+
+print(mymod.myfunc("arg1", true))
+for i = 1, 1000 do
+	mymod.myfunc("foo", false)
+end
+
+c:close()
+
diff --git a/example.lua b/example.lua
deleted file mode 100644
index db9973a..0000000
--- a/example.lua
+++ /dev/null
@@ -1,12 +0,0 @@
-
-
-mymod = require("privsep").wrap("mymod", "dummy session token")
-posix = require("posix")
-
-print(mymod.myfunc("foo", false))
-
-print("posix.getpid:", posix.getpid().pid)
-print("mymod.getpid:", mymod.getpid().pid)
-
-
-
diff --git a/privileged-main.lua b/privileged-main.lua
deleted file mode 100644
index 6aa9681..0000000
--- a/privileged-main.lua
+++ /dev/null
@@ -1,59 +0,0 @@
-msg = ...
-
---print("DEBUG: got message:", msg)
-
-ipcmsg = require("cmsgpack")
-ipcmsg.encode = ipcmsg.pack
-ipcmsg.decode = ipcmsg.unpack
-
-
-function ret_error(errmsg)
-	io.stderr:write("ERROR: "..tostring(errmsg).."\n")
-	return ipcmsg.encode{ status = false, errmsg = errmsg}
-end
-
-function ret_success(result)
-	return ipcmsg.encode{ status = true, errmsg = "success", result = result}
-end
-
-req = ipcmsg.decode(msg)
-
---print("DEBUG: msg decoded")
-
--- path must be absolute for production so users cannot load scripts from
--- non secured dirs
-modules_path = "./modules/"
-
-if type(req.mod) ~= "string" then
-	return ret_error("mod is missing in message or is bad format")
-end
-
-if type(req.func) ~= "string" then
-	return ret_error("func is missing in message or is wrong format")
-end
-
--- make sure we dont have any path elements in modname so we cannot pass
--- modnames like '../myevilmod'
-mfile = modules_path..string.gsub(req.mod, ".*/", "")..".lua"
-
--- load the module
-m = dofile(mfile)
---print("DEBUG: mfile:", mfile)
---print("DEBUG: '"..req.func.."' type:", type(m[req.func]))
-
--- check that the func we want exists
-if type(m[req.func]) ~= "function" then
-	ret_error(func..": not a function in '".. mfile .."'")
-end
-
--- TODO: check permissions here
-print("Calling '"..req.mod.."."..req.func.."'")
-
---print("DEBUG: args:", req.args)
--- execute the func and pack the return values into a table
-result = { m[req.func](unpack(req.args)) }
---result = { m[func](unpack(req.args or {})) }
-
---print("DEBUG: result:", result)
-
-return ret_success(result)
diff --git a/privsep.lua b/privsep.lua
deleted file mode 100644
index b6e8f95..0000000
--- a/privsep.lua
+++ /dev/null
@@ -1,40 +0,0 @@
-
-ipcmsg = require("cmsgpack")
-ipcmsg.encode = ipcmsg.pack
-ipcmsg.decode = ipcmsg.unpack
-
-socket = require("socket")
-socket.unix = require("socket.unix")
-
-
-local modules_path = "./modules"
-
-local privsep = {}
-
-function privsep.call_privileged(mod, func, sectoken, args)
-	local c = assert(socket.unix())
-	assert(c:connect("/var/run/privsep/root.sock"))
-
-	local req = { mod = mod, func = func, args = args, sectoken = sectoken }
-	c:send(ipcmsg.encode(req))
-	local retmsg, errmsg = c:receive("*a")
-	if retmsg then
-		local data = ipcmsg.decode(retmsg)
-		return unpack(data.result or {})
-	end
-	return nil
-end
-
-function privsep.wrap(modname, sessionid)
-	local mod = dofile(modules_path.."/"..modname..".lua")
-	local f = {}
-	for k,v in pairs(mod) do
-		f[k] = function(...)
-			return privsep.call_privileged(modname, k, sessionid, {...})
-		end
-	end
-	return f
-end
-
-return privsep
-
diff --git a/bin/Makefile b/server/Makefile
index 07a522a..0f14b48 100644
--- a/bin/Makefile
+++ b/server/Makefile
@@ -1,5 +1,6 @@
 
 COMPILE_PROG = $(CC) $(CFLAGS) $(LDFLAGS) -o $@ $($@-objs) $($@-libs)
+COMPILE_LUALIB = $(CC) $(CFLAGS) $(LDFLAGS) -shared -o $@ $($@-objs) $($@-libs)
 
 CFLAGS ?= -g
 
diff --git a/bin/conn.c b/server/conn.c
index f953d09..f167cdd 100644
--- a/bin/conn.c
+++ b/server/conn.c
@@ -22,19 +22,8 @@
 #define log_perror(x) perror(x)
 #endif
 
-#ifndef MSG_MAX_SIZE
-#define MSG_MAX_SIZE 16386
-#endif
-
 static struct ev_io accept_io;
 
-struct conn {
-        struct ev_io io;
-        struct ev_timer timeout;
-        size_t num_read;
-	char msg[MSG_MAX_SIZE];
-};
-
 static void conn_free(struct ev_loop *loop, struct conn *rm)
 {
 	int fd = rm->io.fd;
@@ -42,6 +31,7 @@ static void conn_free(struct ev_loop *loop, struct conn *rm)
 	ev_io_stop(loop, &rm->io);
 	ev_timer_stop(loop, &rm->timeout);
 	close(fd);
+	close_lua(rm);
 	free(rm);
 	log_debug("Connection closed");
 }
@@ -63,8 +53,10 @@ static void conn_recv_cb (struct ev_loop *loop, struct ev_io *w,
 	conn->num_read += len;
 	if (conn->num_read >= sizeof(conn->msg))
 		goto err;
-	
-	call_lua(conn->io.fd, conn->msg, conn->num_read);
+
+	call_lua(conn, conn->msg, conn->num_read);
+	conn->num_read = 0;
+	return;
 
 err:
 	conn_free(loop, conn);
@@ -98,6 +90,8 @@ static void conn_accept_cb(struct ev_loop *loop, struct ev_io *w,
 	ev_io_start(loop, &conn->io);
         ev_timer_init(&conn->timeout, conn_timeout_cb, 10.0, 0.);
         ev_timer_start(loop, &conn->timeout);
+
+	init_lua(conn);
 }
 
 
diff --git a/server/conn.h b/server/conn.h
new file mode 100644
index 0000000..f698054
--- /dev/null
+++ b/server/conn.h
@@ -0,0 +1,21 @@
+#ifndef CONN_H
+#define CONN_H
+
+#include <ev.h>
+#include <lua.h>
+
+#ifndef MSG_MAX_SIZE
+#define MSG_MAX_SIZE 16386
+#endif
+
+struct conn {
+        struct ev_io io;
+        struct ev_timer timeout;
+        size_t num_read;
+	lua_State *L;
+	char msg[MSG_MAX_SIZE];
+};
+
+int conn_init(struct ev_loop *loop, const char *socket_path);
+
+#endif
diff --git a/server/handler.lua b/server/handler.lua
new file mode 100644
index 0000000..41a02fb
--- /dev/null
+++ b/server/handler.lua
@@ -0,0 +1,64 @@
+
+--print("DEBUG: got message:", msg)
+
+--ipcmsg = require("json")
+ipcmsg = require("cmsgpack")
+ipcmsg.encode = ipcmsg.pack
+ipcmsg.decode = ipcmsg.unpack
+
+ml =  require("ml")
+
+modules_path = "../modules/"
+
+mods = {}
+
+local function ret_error(errmsg)
+	io.stderr:write("ERROR: "..tostring(errmsg).."\n")
+	return ipcmsg.encode{ status = false, errmsg = errmsg}
+end
+
+local function ret_success(...)
+	return ipcmsg.encode{ status = true, errmsg = "success",
+		result = {...} }
+end
+
+reqhandler = {}
+function reqhandler.load(req)
+	-- make sure we dont have any path elements in modname so we cannot pass
+	-- modnames like '../myevilmod'
+	local file = modules_path..string.gsub(req.modname, ".*/", "")..".lua"
+	mods[req.modidx] = dofile(file)
+	if mods[req.modidx] == nil then
+		return ret_error(file)
+	end
+	return true
+end
+
+function reqhandler.call(req)
+	if req.modidx == nil or req.func == nil then
+		return ret_error("failed to call function "..tostring(req.func))
+	end
+	local m = mods[req.modidx]
+	-- check that the func we want exists
+	if type(m[req.func]) ~= "function" then
+		ret_error(func..": not a function in '".. mfile .."'")
+	end
+
+	-- TODO: check permissions here
+--	print("DEBUG: Calling mods["..req.modidx.."]."..req.func)
+
+	-- execute the func and pack the return values into a table
+	return m[req.func](unpack(req.args))
+end
+
+function handler(msg)
+	local req = ipcmsg.decode(msg)
+--	print("DEBUG: req="..ml.tstring(req))
+	if type(req.type) ~= "string" then
+		return ret_error("request type missing")
+	end
+	if type(reqhandler[req.type]) == "function" then
+		return ret_success(reqhandler[req.type](req))
+	end
+	return ret_error("no handler for request type "..req.type)
+end
diff --git a/server/list.h b/server/list.h
new file mode 100644
index 0000000..1fca5e7
--- /dev/null
+++ b/server/list.h
@@ -0,0 +1,112 @@
+/* list.h - Single and double linked list macros
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 or later as
+ * published by the Free Software Foundation.
+ *
+ * See http://www.gnu.org/ for details.
+ *
+ * This is more or less based on the code in the linux kernel. There are
+ * minor differences and this is only a subset of the kernel version.
+ */
+
+#ifndef LIST_H
+#define LIST_H
+
+#ifndef NULL
+#define NULL 0L
+#endif
+
+#ifndef offsetof
+#ifdef __compiler_offsetof
+#define offsetof(TYPE,MEMBER) __compiler_offsetof(TYPE,MEMBER)
+#else
+#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
+#endif
+#endif
+
+#ifndef container_of
+#define container_of(ptr, type, member) ({                      \
+        const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
+        (type *)( (char *)__mptr - offsetof(type,member) );})
+#endif
+
+struct list_head {
+	struct list_head *next, *prev;
+};
+
+#define LIST_INITIALIZER(l) { .next = &l, .prev = &l }
+
+static inline void list_init(struct list_head *list)
+{
+	list->next = list;
+	list->prev = list;
+}
+
+static inline void __list_add(struct list_head *new,
+			      struct list_head *prev,
+			      struct list_head *next)
+{
+	next->prev = new;
+	new->next = next;
+	new->prev = prev;
+	prev->next = new;
+}
+
+static inline void list_add(struct list_head *new, struct list_head *head)
+{
+	__list_add(new, head, head->next);
+}
+
+static inline void list_add_tail(struct list_head *new, struct list_head *head)
+{
+	__list_add(new, head->prev, head);
+}
+
+static inline void __list_del(struct list_head * prev, struct list_head * next)
+{
+	next->prev = prev;
+	prev->next = next;
+}
+
+static inline void list_del(struct list_head *entry)
+{
+	__list_del(entry->prev, entry->next);
+	entry->next = NULL;
+	entry->prev = NULL;
+}
+
+static inline int list_hashed(const struct list_head *n)
+{
+	return n->next != n && n->next != NULL;
+}
+
+static inline int list_empty(const struct list_head *n)
+{
+	return !list_hashed(n);
+}
+
+#define list_next(ptr, type, member) \
+	(list_hashed(ptr) ? container_of((ptr)->next,type,member) : NULL)
+
+#define list_entry(ptr, type, member) container_of(ptr,type,member)
+
+#define list_for_each(pos, head) \
+	for (pos = (head)->next; pos != (head); pos = pos->next)
+
+#define list_for_each_safe(pos, n, head) \
+	for (pos = (head)->next, n = pos->next; pos != (head); \
+		pos = n, n = pos->next)
+
+#define list_for_each_entry(pos, head, member)				\
+	for (pos = list_entry((head)->next, typeof(*pos), member);	\
+	     &pos->member != (head); 					\
+	     pos = list_entry(pos->member.next, typeof(*pos), member))
+
+#define list_for_each_entry_safe(pos, n, head, member)			\
+	for (pos = list_entry((head)->next, typeof(*pos), member),	\
+		n = list_entry(pos->member.next, typeof(*pos), member);	\
+	     &pos->member != (head); 					\
+	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
+
+#endif
diff --git a/bin/lua-privsep.c b/server/lua-privsep.c
index d6d750c..65dc39e 100644
--- a/bin/lua-privsep.c
+++ b/server/lua-privsep.c
@@ -1,4 +1,7 @@
+#include <stdarg.h>
 #include <stdio.h>
+#include <stdlib.h>
+
 
 #include <lua.h>
 #include <lauxlib.h>
@@ -35,32 +38,59 @@ static int traceback (lua_State *L) {
 	return 1;
 }
 
-int call_lua(int fd, const char *msg, size_t msglen)
+static void lerror(lua_State *L, const char *fmt, ...)
+{
+	va_list argp;
+	va_start(argp, fmt);
+	vfprintf(stderr, fmt, argp);
+	va_end(argp);
+	lua_close(L);
+	exit(EXIT_FAILURE);
+}
+
+int call_lua(struct conn *c, const char *msg, size_t msglen)
 {
-	const char *luamain = PRIVSEP_PATH "privileged-main.lua";
-	int traceback_index;
 	const char *retbuf;
 	size_t retsize;
+	lua_State *L = c->L;
 
-	lua_State *L = luaL_newstate();
-	luaL_openlibs(L);
-
-	lua_pushcfunction(L, traceback);
-	traceback_index = lua_gettop(L);
-
-	if (luaL_loadfile(L, luamain))
-		return luaL_error(L, "%s", luamain);
-
+	lua_getglobal(L, "handler");
 	lua_pushlstring(L, msg, msglen);
 
 
-	if (lua_pcall(L, 1, 1, traceback_index))
-		return luaL_error(L, "error");
+	if (lua_pcall(L, 1, 1, 0))
+		return luaL_error(L, lua_tostring(L, -1));
 
 	if (!lua_isstring(L, -1))
-		error(L, "function must return string");
-	
+		lerror(L, "handler function must return string\n");
+
 	retbuf = lua_tolstring(L, -1, &retsize);
-	return write(fd, retbuf, retsize);
+	return write(c->io.fd, retbuf, retsize);
+}
+
+int init_lua(struct conn *c)
+{
+	const char *luamain = PRIVSEP_PATH "handler.lua";
+	int traceback_index;
+	const char *retbuf;
+	size_t retsize;
+
+	c->L = luaL_newstate();
+	if (c == NULL)
+		return -1;
+	luaL_openlibs(c->L);
+
+	if (luaL_loadfile(c->L, luamain) || lua_pcall(c->L, 0, 0, 0)) {
+		lerror(c->L, "%s: %s", luamain, lua_tostring(c->L, -1));
+		lua_close(c->L);
+		c->L = NULL;
+		return -1;
+	}
+	return 0;
 }
 
+void close_lua(struct conn *c)
+{
+	lua_close(c->L);
+	c->L = NULL;
+}
diff --git a/server/lua-privsep.h b/server/lua-privsep.h
new file mode 100644
index 0000000..2d27a11
--- /dev/null
+++ b/server/lua-privsep.h
@@ -0,0 +1,11 @@
+#ifndef LUA_PRIVSEP_H
+#define LUA_PRIVSEP_H
+
+#include "conn.h"
+#include <lua.h>
+
+int call_lua(struct conn *c, const char *msg, size_t msglen);
+int init_lua(struct conn *c);
+void close_lua(struct conn *c);
+
+#endif
diff --git a/server/privsep-server b/server/privsep-server
new file mode 100755
index 0000000..5be1ad1
--- /dev/null
+++ b/server/privsep-server
diff --git a/bin/privsep-server.c b/server/privsep-server.c
index 76d3f4c..76d3f4c 100644
--- a/bin/privsep-server.c
+++ b/server/privsep-server.c