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minix/kernel/system/do_privctl.c
Tomas Hruby cca24d06d8 This patch removes the global variables who_p and who_e from the 
kernel (sys task).  The main reason is that these would have to become
cpu local variables on SMP.  Once the system task is not a task but a
genuine part of the kernel there is even less reason to have these
extra variables as proc_ptr will already contain all neccessary
information. In addition converting who_e to the process pointer and
back again all the time will be avoided.

Although proc_ptr will contain all important information, accessing it
as a cpu local variable will be fairly expensive, hence the value
would be assigned to some on stack local variable. Therefore it is
better to add the 'caller' argument to the syscall handlers to pass
the value on stack anyway. It also clearly denotes on who's behalf is
the syscall being executed.

This patch also ANSIfies the syscall function headers.

Last but not least, it also fixes a potential bug in virtual_copy_f()
in case the check is disabled. So far the function in case of a
failure could possible reuse an old who_p in case this function had
not been called from the system task.

virtual_copy_f() takes the caller as a parameter too. In case the
checking is disabled, the caller must be NULL and non NULL if it is
enabled as we must be able to suspend the caller.
2010-02-03 09:04:48 +00:00

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/* The kernel call implemented in this file:
* m_type: SYS_PRIVCTL
*
* The parameters for this kernel call are:
* m2_i1: CTL_ENDPT (process endpoint of target)
* m2_i2: CTL_REQUEST (privilege control request)
* m2_p1: CTL_ARG_PTR (pointer to request data)
*/
#include "../system.h"
#include "../ipc.h"
#include <signal.h>
#include <string.h>
#include <minix/endpoint.h>
#if USE_PRIVCTL
/*===========================================================================*
* do_privctl *
*===========================================================================*/
PUBLIC int do_privctl(struct proc * caller, message * m_ptr)
{
/* Handle sys_privctl(). Update a process' privileges. If the process is not
* yet a system process, make sure it gets its own privilege structure.
*/
struct proc *rp;
int proc_nr;
int priv_id;
int ipc_to_m, kcalls;
int i, r;
struct io_range io_range;
struct mem_range mem_range;
struct priv priv;
int irq;
/* Check whether caller is allowed to make this call. Privileged proceses
* can only update the privileges of processes that are inhibited from
* running by the RTS_NO_PRIV flag. This flag is set when a privileged process
* forks.
*/
if (! (priv(caller)->s_flags & SYS_PROC)) return(EPERM);
if(m_ptr->CTL_ENDPT == SELF) proc_nr = _ENDPOINT_P(caller->p_endpoint);
else if(!isokendpt(m_ptr->CTL_ENDPT, &proc_nr)) return(EINVAL);
rp = proc_addr(proc_nr);
switch(m_ptr->CTL_REQUEST)
{
case SYS_PRIV_ALLOW:
/* Allow process to run. Make sure its privilege structure has already
* been set.
*/
if (!RTS_ISSET(rp, RTS_NO_PRIV) || priv(rp)->s_proc_nr == NONE) {
return(EPERM);
}
RTS_LOCK_UNSET(rp, RTS_NO_PRIV);
return(OK);
case SYS_PRIV_DISALLOW:
/* Disallow process from running. */
if (RTS_ISSET(rp, RTS_NO_PRIV)) return(EPERM);
RTS_LOCK_SET(rp, RTS_NO_PRIV);
return(OK);
case SYS_PRIV_SET_SYS:
/* Set a privilege structure of a blocked system process. */
if (! RTS_ISSET(rp, RTS_NO_PRIV)) return(EPERM);
/* Check whether a static or dynamic privilege id must be allocated. */
priv_id = NULL_PRIV_ID;
if (m_ptr->CTL_ARG_PTR)
{
/* Copy privilege structure from caller */
if((r=data_copy(caller->p_endpoint, (vir_bytes) m_ptr->CTL_ARG_PTR,
SYSTEM, (vir_bytes) &priv, sizeof(priv))) != OK)
return r;
/* See if the caller wants to assign a static privilege id. */
if(!(priv.s_flags & DYN_PRIV_ID)) {
priv_id = priv.s_id;
}
}
/* Make sure this process has its own privileges structure. This may
* fail, since there are only a limited number of system processes.
* Then copy privileges from the caller and restore some defaults.
*/
if ((i=get_priv(rp, priv_id)) != OK)
{
kprintf("do_privctl: unable to allocate priv_id %d: %d\n",
priv_id, i);
return(i);
}
priv_id = priv(rp)->s_id; /* backup privilege id */
*priv(rp) = *priv(caller); /* copy from caller */
priv(rp)->s_id = priv_id; /* restore privilege id */
priv(rp)->s_proc_nr = proc_nr; /* reassociate process nr */
for (i=0; i< NR_SYS_CHUNKS; i++) /* remove pending: */
priv(rp)->s_notify_pending.chunk[i] = 0; /* - notifications */
priv(rp)->s_int_pending = 0; /* - interrupts */
sigemptyset(&priv(rp)->s_sig_pending); /* - signals */
priv(rp)->s_asyntab= -1; /* - asynsends */
priv(rp)->s_asynsize= 0;
/* Set defaults for privilege bitmaps. */
priv(rp)->s_flags= DEF_SYS_F; /* privilege flags */
priv(rp)->s_trap_mask= DEF_SYS_T; /* allowed traps */
ipc_to_m = DEF_SYS_M; /* allowed targets */
kcalls = DEF_SYS_KC; /* allowed kernel calls */
for(i = 0; i < SYS_CALL_MASK_SIZE; i++) {
priv(rp)->s_k_call_mask[i] = (kcalls == NO_C ? 0 : (~0));
}
/* Set defaults for resources: no I/O resources, no memory resources,
* no IRQs, no grant table
*/
priv(rp)->s_nr_io_range= 0;
priv(rp)->s_nr_mem_range= 0;
priv(rp)->s_nr_irq= 0;
priv(rp)->s_grant_table= 0;
priv(rp)->s_grant_entries= 0;
/* Override defaults if the caller has supplied a privilege structure. */
if (m_ptr->CTL_ARG_PTR)
{
/* Copy s_flags. */
priv(rp)->s_flags = priv.s_flags;
/* Copy IRQs */
if(priv.s_flags & CHECK_IRQ) {
if (priv.s_nr_irq < 0 || priv.s_nr_irq > NR_IRQ)
return EINVAL;
priv(rp)->s_nr_irq= priv.s_nr_irq;
for (i= 0; i<priv.s_nr_irq; i++)
{
priv(rp)->s_irq_tab[i]= priv.s_irq_tab[i];
#if 0
kprintf("do_privctl: adding IRQ %d for %d\n",
priv(rp)->s_irq_tab[i], rp->p_endpoint);
#endif
}
}
/* Copy I/O ranges */
if(priv.s_flags & CHECK_IO_PORT) {
if (priv.s_nr_io_range < 0 || priv.s_nr_io_range > NR_IO_RANGE)
return EINVAL;
priv(rp)->s_nr_io_range= priv.s_nr_io_range;
for (i= 0; i<priv.s_nr_io_range; i++)
{
priv(rp)->s_io_tab[i]= priv.s_io_tab[i];
#if 0
kprintf("do_privctl: adding I/O range [%x..%x] for %d\n",
priv(rp)->s_io_tab[i].ior_base,
priv(rp)->s_io_tab[i].ior_limit,
rp->p_endpoint);
#endif
}
}
/* Copy memory ranges */
if(priv.s_flags & CHECK_MEM) {
if (priv.s_nr_mem_range < 0 || priv.s_nr_mem_range > NR_MEM_RANGE)
return EINVAL;
priv(rp)->s_nr_mem_range= priv.s_nr_mem_range;
for (i= 0; i<priv.s_nr_mem_range; i++)
{
priv(rp)->s_mem_tab[i]= priv.s_mem_tab[i];
#if 0
kprintf("do_privctl: adding mem range [%x..%x] for %d\n",
priv(rp)->s_mem_tab[i].mr_base,
priv(rp)->s_mem_tab[i].mr_limit,
rp->p_endpoint);
#endif
}
}
/* Copy trap mask. */
priv(rp)->s_trap_mask = priv.s_trap_mask;
/* Copy target mask. */
memcpy(&ipc_to_m, &priv.s_ipc_to, sizeof(ipc_to_m));
/* Copy kernel call mask. */
memcpy(priv(rp)->s_k_call_mask, priv.s_k_call_mask,
sizeof(priv(rp)->s_k_call_mask));
}
/* Fill in target mask. */
for (i=0; i < NR_SYS_PROCS; i++) {
if (ipc_to_m & (1 << i))
set_sendto_bit(rp, i);
else
unset_sendto_bit(rp, i);
}
return(OK);
case SYS_PRIV_SET_USER:
/* Set a privilege structure of a blocked user process. */
if (!RTS_ISSET(rp, RTS_NO_PRIV)) return(EPERM);
/* Link the process to the privilege structure of the root user
* process all the user processes share.
*/
priv(rp) = priv_addr(USER_PRIV_ID);
return(OK);
case SYS_PRIV_ADD_IO:
if (RTS_ISSET(rp, RTS_NO_PRIV))
return(EPERM);
/* Only system processes get I/O resources? */
if (!(priv(rp)->s_flags & SYS_PROC))
return EPERM;
#if 0 /* XXX -- do we need a call for this? */
if (strcmp(rp->p_name, "fxp") == 0 ||
strcmp(rp->p_name, "rtl8139") == 0)
{
kprintf("setting ipc_stats_target to %d\n", rp->p_endpoint);
ipc_stats_target= rp->p_endpoint;
}
#endif
/* Get the I/O range */
data_copy(caller->p_endpoint, (vir_bytes) m_ptr->CTL_ARG_PTR,
SYSTEM, (vir_bytes) &io_range, sizeof(io_range));
priv(rp)->s_flags |= CHECK_IO_PORT; /* Check I/O accesses */
i= priv(rp)->s_nr_io_range;
if (i >= NR_IO_RANGE)
return ENOMEM;
priv(rp)->s_io_tab[i].ior_base= io_range.ior_base;
priv(rp)->s_io_tab[i].ior_limit= io_range.ior_limit;
priv(rp)->s_nr_io_range++;
return OK;
case SYS_PRIV_ADD_MEM:
if (RTS_ISSET(rp, RTS_NO_PRIV))
return(EPERM);
/* Only system processes get memory resources? */
if (!(priv(rp)->s_flags & SYS_PROC))
return EPERM;
/* Get the memory range */
if((r=data_copy(caller->p_endpoint, (vir_bytes) m_ptr->CTL_ARG_PTR,
SYSTEM, (vir_bytes) &mem_range, sizeof(mem_range))) != OK)
return r;
priv(rp)->s_flags |= CHECK_MEM; /* Check memory mappings */
i= priv(rp)->s_nr_mem_range;
if (i >= NR_MEM_RANGE)
return ENOMEM;
priv(rp)->s_mem_tab[i].mr_base= mem_range.mr_base;
priv(rp)->s_mem_tab[i].mr_limit= mem_range.mr_limit;
priv(rp)->s_nr_mem_range++;
return OK;
case SYS_PRIV_ADD_IRQ:
if (RTS_ISSET(rp, RTS_NO_PRIV))
return(EPERM);
/* Only system processes get IRQs? */
if (!(priv(rp)->s_flags & SYS_PROC))
return EPERM;
data_copy(caller->p_endpoint, (vir_bytes) m_ptr->CTL_ARG_PTR,
SYSTEM, (vir_bytes) &irq, sizeof(irq));
priv(rp)->s_flags |= CHECK_IRQ; /* Check IRQs */
i= priv(rp)->s_nr_irq;
if (i >= NR_IRQ)
return ENOMEM;
priv(rp)->s_irq_tab[i]= irq;
priv(rp)->s_nr_irq++;
return OK;
case SYS_PRIV_QUERY_MEM:
{
phys_bytes addr, limit;
struct priv *sp;
/* See if a certain process is allowed to map in certain physical
* memory.
*/
addr = (phys_bytes) m_ptr->CTL_PHYSSTART;
limit = addr + (phys_bytes) m_ptr->CTL_PHYSLEN - 1;
if(limit < addr)
return EPERM;
if(!(sp = priv(rp)))
return EPERM;
if (!(sp->s_flags & SYS_PROC))
return EPERM;
for(i = 0; i < sp->s_nr_mem_range; i++) {
if(addr >= sp->s_mem_tab[i].mr_base &&
limit <= sp->s_mem_tab[i].mr_limit)
return OK;
}
return EPERM;
}
default:
kprintf("do_privctl: bad request %d\n", m_ptr->CTL_REQUEST);
return EINVAL;
}
}
#endif /* USE_PRIVCTL */
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