1 2 /* Call mask ACL management. */ 3 4 #include <minix/drivers.h> 5 6 #include "proto.h" 7 #include "glo.h" 8 #include "util.h" 9 10 #define NO_ACL -1 11 #define USER_ACL 0 12 #define FIRST_SYS_ACL 1 13 14 static bitchunk_t acl_mask[NR_SYS_PROCS][VM_CALL_MASK_SIZE]; 15 static bitchunk_t acl_inuse[BITMAP_CHUNKS(NR_SYS_PROCS)]; 16 17 /* 18 * Initialize ACL data structures. 19 */ 20 void 21 acl_init(void) 22 { 23 int i; 24 25 for (i = 0; i < ELEMENTS(vmproc); i++) 26 vmproc[i].vm_acl = NO_ACL; 27 28 memset(acl_mask, 0, sizeof(acl_mask)); 29 memset(acl_inuse, 0, sizeof(acl_inuse)); 30 } 31 32 /* 33 * Check whether a process is allowed to make a certain (zero-based) call. 34 * Return OK or an error. 35 */ 36 int 37 acl_check(struct vmproc *vmp, int call) 38 { 39 /* If the process has no ACL, all calls are allowed.. for now. */ 40 if (vmp->vm_acl == NO_ACL) { 41 printf("VM: calling process %u has no ACL!\n", 42 vmp->vm_endpoint); 43 44 return OK; 45 } 46 47 /* See if the call is allowed. */ 48 if (!GET_BIT(acl_mask[vmp->vm_acl], call)) 49 return EPERM; 50 51 return OK; 52 } 53 54 /* 55 * Assign a call mask to a process. User processes share the first ACL entry. 56 * System processes are assigned to any of the other slots. For user 57 * processes, no call mask need to be provided: it will simply be inherited in 58 * that case. 59 */ 60 void 61 acl_set(struct vmproc *vmp, bitchunk_t *mask, int sys_proc) 62 { 63 int i; 64 65 acl_clear(vmp); 66 67 if (sys_proc) { 68 for (i = FIRST_SYS_ACL; i < NR_SYS_PROCS; i++) 69 if (!GET_BIT(acl_inuse, i)) 70 break; 71 72 /* 73 * This should never happen. If it does, then different user 74 * processes have been assigned call masks separately. It is 75 * RS's responsibility to prevent that. 76 */ 77 if (i == NR_SYS_PROCS) { 78 printf("VM: no ACL entries available!\n"); 79 return; 80 } 81 } else 82 i = USER_ACL; 83 84 if (!GET_BIT(acl_inuse, i) && mask == NULL) 85 printf("VM: WARNING: inheriting uninitialized ACL mask\n"); 86 87 SET_BIT(acl_inuse, i); 88 vmp->vm_acl = i; 89 90 if (mask != NULL) 91 memcpy(&acl_mask[vmp->vm_acl], mask, sizeof(acl_mask[0])); 92 } 93 94 /* 95 * A process has forked. User processes inherit their parent's ACL by default, 96 * although they may be turned into system processes later. System processes 97 * do not inherit an ACL, and will have to be assigned one before getting to 98 * run. 99 */ 100 void 101 acl_fork(struct vmproc *vmp) 102 { 103 if (vmp->vm_acl != USER_ACL) 104 vmp->vm_acl = NO_ACL; 105 } 106 107 /* 108 * A process has exited. Decrease the reference count on its ACL entry, and 109 * mark the process as having no ACL. 110 */ 111 void 112 acl_clear(struct vmproc *vmp) 113 { 114 if (vmp->vm_acl != NO_ACL) { 115 if (vmp->vm_acl != USER_ACL) 116 UNSET_BIT(acl_inuse, vmp->vm_acl); 117 118 vmp->vm_acl = NO_ACL; 119 } 120 } 121