Code: static int getnum (lua_State *L, const char **fmt, int df) {
   if (!isdigit(**fmt))  /* no number? */
     return df;  /* return default value */
   else {
     int a = 0;
     do {
      if (a > (INT_MAX / 10) || a * 10 > (INT_MAX - (**fmt - '0')))
        luaL_error(L, "integral size overflow");
       a = a*10 + *((*fmt)++) - '0';
     } while (isdigit(**fmt));
     return a;
  }
}

Commit Message: Security: update Lua struct package for security.

During an auditing Apple found that the "struct" Lua package
we ship with Redis (http://www.inf.puc-rio.br/~roberto/struct/) contains
a security problem. A bound-checking statement fails because of integer
overflow. The bug exists since we initially integrated this package with
Lua, when scripting was introduced, so every version of Redis with
EVAL/EVALSHA capabilities exposed is affected.

Instead of just fixing the bug, the library was updated to the latest
version shipped by the author.
CWE ID: CWE-190
static int getnum (lua_State *L, const char **fmt, int df) {
static int getnum (const char **fmt, int df) {
   if (!isdigit(**fmt))  /* no number? */
     return df;  /* return default value */
   else {
     int a = 0;
     do {
       a = a*10 + *((*fmt)++) - '0';
     } while (isdigit(**fmt));
     return a;
  }
}
