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 40 /* VM makes asynchronous calls to itself. Always allow those. */ 41 if (vmp->vm_endpoint == VM_PROC_NR) 42 return OK; 43 44 /* If the process has no ACL, all calls are allowed.. for now. */ 45 if (vmp->vm_acl == NO_ACL) { 46 printf("VM: calling process %u has no ACL!\n", 47 vmp->vm_endpoint); 48 49 return OK; 50 } 51 52 /* See if the call is allowed. */ 53 if (!GET_BIT(acl_mask[vmp->vm_acl], call)) 54 return EPERM; 55 56 return OK; 57 } 58 59 /* 60 * Assign a call mask to a process. User processes share the first ACL entry. 61 * System processes are assigned to any of the other slots. For user 62 * processes, no call mask need to be provided: it will simply be inherited in 63 * that case. 64 */ 65 void 66 acl_set(struct vmproc *vmp, bitchunk_t *mask, int sys_proc) 67 { 68 int i; 69 70 acl_clear(vmp); 71 72 if (sys_proc) { 73 for (i = FIRST_SYS_ACL; i < NR_SYS_PROCS; i++) 74 if (!GET_BIT(acl_inuse, i)) 75 break; 76 77 /* 78 * This should never happen. If it does, then different user 79 * processes have been assigned call masks separately. It is 80 * RS's responsibility to prevent that. 81 */ 82 if (i == NR_SYS_PROCS) { 83 printf("VM: no ACL entries available!\n"); 84 return; 85 } 86 } else 87 i = USER_ACL; 88 89 if (!GET_BIT(acl_inuse, i) && mask == NULL) 90 printf("VM: WARNING: inheriting uninitialized ACL mask\n"); 91 92 SET_BIT(acl_inuse, i); 93 vmp->vm_acl = i; 94 95 if (mask != NULL) 96 memcpy(&acl_mask[vmp->vm_acl], mask, sizeof(acl_mask[0])); 97 } 98 99 /* 100 * A process has forked. User processes inherit their parent's ACL by default, 101 * although they may be turned into system processes later. System processes 102 * do not inherit an ACL, and will have to be assigned one before getting to 103 * run. 104 */ 105 void 106 acl_fork(struct vmproc *vmp) 107 { 108 if (vmp->vm_acl != USER_ACL) 109 vmp->vm_acl = NO_ACL; 110 } 111 112 /* 113 * A process has exited. Decrease the reference count on its ACL entry, and 114 * mark the process as having no ACL. 115 */ 116 void 117 acl_clear(struct vmproc *vmp) 118 { 119 if (vmp->vm_acl != NO_ACL) { 120 if (vmp->vm_acl != USER_ACL) 121 UNSET_BIT(acl_inuse, vmp->vm_acl); 122 123 vmp->vm_acl = NO_ACL; 124 } 125 } 126