Re: [CHECKER] 4 security holes in 2.4.4-ac8

[Dawson Engler <engler@csl.Stanford.EDU>]

>  > [BUG] raddr seems to be a user pointer, but is written at the end of
>  >       the system call.
>  > 
>  > ipc/shm.c: ERROR: system call 'sys_shmat' derefs non-tainted param= 3
>  > 
>  > asmlinkage long sys_shmat (int shmid, char *shmaddr, int shmflg, ulong *raddr)
>  > {
>  >         struct shmid_kernel *shp;
>  > 
>  > 
>  > 	...
>  >         *raddr = (unsigned long) user_addr;
>  >         err = 0;
>  >         if (IS_ERR(user_addr))
>  >                 err = PTR_ERR(user_addr);
>  >         return err;
> 
> Believe it or not, this one is OK :-)
> 
> All callers pass in a pointer to a local stack kernel variable
> in raddr.

Ah.  I assumed that "sys_*" meant that all pointers were from user space ---
is this generally not the case?  (Also, are there other functions called 
directly from user space that don't have the sys_* prefix?)