121 lines
2.5 KiB
C
121 lines
2.5 KiB
C
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/* Call mask ACL management. */
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#include <minix/drivers.h>
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#include "proto.h"
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#include "glo.h"
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#include "util.h"
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#define NO_ACL -1
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#define USER_ACL 0
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#define FIRST_SYS_ACL 1
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static bitchunk_t acl_mask[NR_SYS_PROCS][VM_CALL_MASK_SIZE];
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static bitchunk_t acl_inuse[BITMAP_CHUNKS(NR_SYS_PROCS)];
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/*
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* Initialize ACL data structures.
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*/
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void
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acl_init(void)
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{
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int i;
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for (i = 0; i < ELEMENTS(vmproc); i++)
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vmproc[i].vm_acl = NO_ACL;
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memset(acl_mask, 0, sizeof(acl_mask));
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memset(acl_inuse, 0, sizeof(acl_inuse));
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}
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/*
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* Check whether a process is allowed to make a certain (zero-based) call.
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* Return OK or an error.
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*/
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int
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acl_check(struct vmproc *vmp, int call)
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{
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/* If the process has no ACL, all calls are allowed.. for now. */
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if (vmp->vm_acl == NO_ACL) {
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printf("VM: calling process %u has no ACL!\n",
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vmp->vm_endpoint);
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return OK;
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}
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/* See if the call is allowed. */
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if (!GET_BIT(acl_mask[vmp->vm_acl], call))
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return EPERM;
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return OK;
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}
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/*
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* Assign a call mask to a process. User processes share the first ACL entry.
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* System processes are assigned to any of the other slots. For user
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* processes, no call mask need to be provided: it will simply be inherited in
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* that case.
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*/
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void
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acl_set(struct vmproc *vmp, bitchunk_t *mask, int sys_proc)
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{
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int i;
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acl_clear(vmp);
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if (sys_proc) {
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for (i = FIRST_SYS_ACL; i < NR_SYS_PROCS; i++)
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if (!GET_BIT(acl_inuse, i))
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break;
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/*
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* This should never happen. If it does, then different user
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* processes have been assigned call masks separately. It is
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* RS's responsibility to prevent that.
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*/
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if (i == NR_SYS_PROCS) {
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printf("VM: no ACL entries available!\n");
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return;
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}
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} else
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i = USER_ACL;
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if (!GET_BIT(acl_inuse, i) && mask == NULL)
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printf("VM: WARNING: inheriting uninitialized ACL mask\n");
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SET_BIT(acl_inuse, i);
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vmp->vm_acl = i;
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if (mask != NULL)
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memcpy(&acl_mask[vmp->vm_acl], mask, sizeof(acl_mask[0]));
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}
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/*
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* A process has forked. User processes inherit their parent's ACL by default,
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* although they may be turned into system processes later. System processes
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* do not inherit an ACL, and will have to be assigned one before getting to
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* run.
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*/
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void
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acl_fork(struct vmproc *vmp)
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{
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if (vmp->vm_acl != USER_ACL)
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vmp->vm_acl = NO_ACL;
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}
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/*
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* A process has exited. Decrease the reference count on its ACL entry, and
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* mark the process as having no ACL.
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*/
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void
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acl_clear(struct vmproc *vmp)
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{
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if (vmp->vm_acl != NO_ACL) {
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if (vmp->vm_acl != USER_ACL)
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UNSET_BIT(acl_inuse, vmp->vm_acl);
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vmp->vm_acl = NO_ACL;
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}
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}
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