commit 364e569945c044fd18c70ee1bc851364534aef97
parent 63295f1f7fa052fabcb4d69d49203cf33a7deef0
Author: Roberto Ierusalimschy <roberto@inf.puc-rio.br>
Date: Tue, 9 Jun 2020 16:11:34 -0300
Avoid calling 'fprintf' with NULL
Avoid undefined behavior in calls like «fprintf("%s", NULL)».
('lua_writestringerror' is implemented as 'fprintf', and 'lua_tostring'
can return NULL if object is not a string.)
Diffstat:
3 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/lauxlib.c b/lauxlib.c
@@ -995,8 +995,10 @@ static void *l_alloc (void *ud, void *ptr, size_t osize, size_t nsize) {
static int panic (lua_State *L) {
+ const char *msg = lua_tostring(L, -1);
+ if (msg == NULL) msg = "error object is not a string";
lua_writestringerror("PANIC: unprotected error in call to Lua API (%s)\n",
- lua_tostring(L, -1));
+ msg);
return 0; /* return to Lua to abort */
}
diff --git a/ldblib.c b/ldblib.c
@@ -417,7 +417,7 @@ static int db_debug (lua_State *L) {
return 0;
if (luaL_loadbuffer(L, buffer, strlen(buffer), "=(debug command)") ||
lua_pcall(L, 0, 0, 0))
- lua_writestringerror("%s\n", lua_tostring(L, -1));
+ lua_writestringerror("%s\n", luaL_tolstring(L, -1, NULL));
lua_settop(L, 0); /* remove eventual returns */
}
}
diff --git a/ltests.c b/ltests.c
@@ -73,8 +73,10 @@ static void badexit (const char *fmt, const char *s1, const char *s2) {
static int tpanic (lua_State *L) {
+ const char *msg = lua_tostring(L, -1);
+ if (msg == NULL) msg = "error object is not a string";
return (badexit("PANIC: unprotected error in call to Lua API (%s)\n",
- lua_tostring(L, -1), NULL),
+ msg, NULL),
0); /* do not return to Lua */
}