X-Git-Url: https://git.saurik.com/redis.git/blobdiff_plain/e4669c045d5bc0f7420814cb66f13f03ac29e29a..93a74949d7bb5d0c4115d1bf45f856c368badf31:/src/scripting.c diff --git a/src/scripting.c b/src/scripting.c index e38d0807..4c7de33b 100644 --- a/src/scripting.c +++ b/src/scripting.c @@ -15,6 +15,7 @@ char *redisProtocolToLuaType_Error(lua_State *lua, char *reply); char *redisProtocolToLuaType_MultiBulk(lua_State *lua, char *reply); int redis_math_random (lua_State *L); int redis_math_randomseed (lua_State *L); +void sha1hex(char *digest, char *script, size_t len); /* Take a Redis reply in the Redis protocol format and convert it into a * Lua type. Thanks to this function, and the introduction of not connected @@ -306,6 +307,25 @@ int luaRedisPCallCommand(lua_State *lua) { return luaRedisGenericCommand(lua,0); } +/* This adds redis.sha1hex(string) to Lua scripts using the same hashing + * function used for sha1ing lua scripts. */ +int luaRedisSha1hexCommand(lua_State *lua) { + int argc = lua_gettop(lua); + char digest[41]; + size_t len; + char *s; + + if (argc != 1) { + luaPushError(lua, "wrong number of arguments"); + return 1; + } + + s = (char*)lua_tolstring(lua,1,&len); + sha1hex(digest,s,len); + lua_pushstring(lua,digest); + return 1; +} + int luaLogCommand(lua_State *lua) { int j, argc = lua_gettop(lua); int level; @@ -392,6 +412,43 @@ void luaLoadLibraries(lua_State *lua) { #endif } +/* This function installs metamethods in the global table _G that prevent + * the creation of globals accidentally. + * + * It should be the last to be called in the scripting engine initialization + * sequence, because it may interact with creation of globals. */ +void scriptingEnableGlobalsProtection(lua_State *lua) { + char *s[32]; + sds code = sdsempty(); + int j = 0; + + /* strict.lua from: http://metalua.luaforge.net/src/lib/strict.lua.html. + * Modified to be adapted to Redis. */ + s[j++]="local mt = {}\n"; + s[j++]="setmetatable(_G, mt)\n"; + s[j++]="mt.__newindex = function (t, n, v)\n"; + s[j++]=" if debug.getinfo(2) then\n"; + s[j++]=" local w = debug.getinfo(2, \"S\").what\n"; + s[j++]=" if w ~= \"main\" and w ~= \"C\" then\n"; + s[j++]=" error(\"Script attempted to create global variable '\"..tostring(n)..\"'\", 2)\n"; + s[j++]=" end\n"; + s[j++]=" end\n"; + s[j++]=" rawset(t, n, v)\n"; + s[j++]="end\n"; + s[j++]="mt.__index = function (t, n)\n"; + s[j++]=" if debug.getinfo(2) and debug.getinfo(2, \"S\").what ~= \"C\" then\n"; + s[j++]=" error(\"Script attempted to access unexisting global variable '\"..tostring(n)..\"'\", 2)\n"; + s[j++]=" end\n"; + s[j++]=" return rawget(t, n)\n"; + s[j++]="end\n"; + s[j++]=NULL; + + for (j = 0; s[j] != NULL; j++) code = sdscatlen(code,s[j],strlen(s[j])); + luaL_loadbuffer(lua,code,sdslen(code),"@enable_strict_lua"); + lua_pcall(lua,0,0,0); + sdsfree(code); +} + /* Initialize the scripting environment. * It is possible to call this function to reset the scripting environment * assuming that we call scriptingRelease() before. @@ -439,6 +496,11 @@ void scriptingInit(void) { lua_pushnumber(lua,REDIS_WARNING); lua_settable(lua,-3); + /* redis.sha1hex */ + lua_pushstring(lua, "sha1hex"); + lua_pushcfunction(lua, luaRedisSha1hexCommand); + lua_settable(lua, -3); + /* Finally set the table as 'redis' global var. */ lua_setglobal(lua,"redis"); @@ -463,7 +525,7 @@ void scriptingInit(void) { " if b == false then b = '' end\n" " return aflags |= REDIS_LUA_CLIENT; } + /* Lua beginners ofter don't use "local", this is likely to introduce + * subtle bugs in their code. To prevent problems we protect accesses + * to global variables. */ + scriptingEnableGlobalsProtection(lua); + server.lua = lua; } @@ -491,10 +558,13 @@ void scriptingReset(void) { scriptingInit(); } -/* Hash the scripit into a SHA1 digest. We use this as Lua function name. - * Digest should point to a 41 bytes buffer: 40 for SHA1 converted into an +/* Perform the SHA1 of the input string. We use this both for hasing script + * bodies in order to obtain the Lua function name, and in the implementation + * of redis.sha1(). + * + * 'digest' should point to a 41 bytes buffer: 40 for SHA1 converted into an * hexadecimal number, plus 1 byte for null term. */ -void hashScript(char *digest, char *script, size_t len) { +void sha1hex(char *digest, char *script, size_t len) { SHA1_CTX ctx; unsigned char hash[20]; char *cset = "0123456789abcdef"; @@ -606,7 +676,7 @@ int luaCreateFunction(redisClient *c, lua_State *lua, char *funcname, robj *body funcdef = sdscatlen(funcdef,body->ptr,sdslen(body->ptr)); funcdef = sdscatlen(funcdef," end",4); - if (luaL_loadbuffer(lua,funcdef,sdslen(funcdef),"func definition")) { + if (luaL_loadbuffer(lua,funcdef,sdslen(funcdef),"@user_script")) { addReplyErrorFormat(c,"Error compiling script (new function): %s\n", lua_tostring(lua,-1)); lua_pop(lua,1); @@ -667,7 +737,7 @@ void evalGenericCommand(redisClient *c, int evalsha) { funcname[1] = '_'; if (!evalsha) { /* Hash the code if this is an EVAL call */ - hashScript(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr)); + sha1hex(funcname+2,c->argv[1]->ptr,sdslen(c->argv[1]->ptr)); } else { /* We already have the SHA if it is a EVALSHA */ int j; @@ -841,7 +911,7 @@ void scriptCommand(redisClient *c) { funcname[0] = 'f'; funcname[1] = '_'; - hashScript(funcname+2,c->argv[2]->ptr,sdslen(c->argv[2]->ptr)); + sha1hex(funcname+2,c->argv[2]->ptr,sdslen(c->argv[2]->ptr)); sha = sdsnewlen(funcname+2,40); if (dictFind(server.lua_scripts,sha) == NULL) { if (luaCreateFunction(c,server.lua,funcname,c->argv[2])