1 /* Workaround for http://bugs.python.org/issue4835 */
2 #ifndef SIZEOF_SOCKET_T
3 #define SIZEOF_SOCKET_T SIZEOF_INT
4 #endif
5
6 #include <Python.h>
7 #include <unistd.h>
8 #include <stdlib.h>
9 #include <ctype.h>
10 #include <errno.h>
11 #include <getopt.h>
12 #include <limits.h>
13 #include <sepol/sepol.h>
14 #include <sepol/policydb.h>
15 #include <sepol/policydb/services.h>
16 #include <selinux/selinux.h>
17
18 #define UNKNOWN -1
19 #define BADSCON -2
20 #define BADTCON -3
21 #define BADTCLASS -4
22 #define BADPERM -5
23 #define BADCOMPUTE -6
24 #define NOPOLICY -7
25 #define ALLOW 0
26 #define DONTAUDIT 1
27 #define TERULE 2
28 #define BOOLEAN 3
29 #define CONSTRAINT 4
30 #define RBAC 5
31 #define BOUNDS 6
32
33 struct boolean_t {
34 char *name;
35 int active;
36 };
37
38 static struct boolean_t **boollist = NULL;
39 static int boolcnt = 0;
40
41 struct avc_t {
42 sepol_handle_t *handle;
43 sepol_policydb_t *policydb;
44 sepol_security_id_t ssid;
45 sepol_security_id_t tsid;
46 sepol_security_class_t tclass;
47 sepol_access_vector_t av;
48 };
49
50 static struct avc_t *avc = NULL;
51
52 static sidtab_t sidtab;
53
load_booleans(const sepol_bool_t * boolean,void * arg)54 static int load_booleans(const sepol_bool_t * boolean,
55 void *arg __attribute__ ((__unused__)))
56 {
57 boollist[boolcnt] = malloc(sizeof(struct boolean_t));
58 boollist[boolcnt]->name = strdup(sepol_bool_get_name(boolean));
59 boollist[boolcnt]->active = sepol_bool_get_value(boolean);
60 boolcnt++;
61 return 0;
62 }
63
check_booleans(struct boolean_t ** bools)64 static int check_booleans(struct boolean_t **bools)
65 {
66 char errormsg[PATH_MAX];
67 struct sepol_av_decision avd;
68 unsigned int reason;
69 int rc;
70 int i;
71 sepol_bool_key_t *key = NULL;
72 sepol_bool_t *boolean = NULL;
73 int fcnt = 0;
74 int *foundlist = calloc(boolcnt, sizeof(int));
75 if (!foundlist) {
76 PyErr_SetString( PyExc_MemoryError, "Out of memory\n");
77 return fcnt;
78 }
79 for (i = 0; i < boolcnt; i++) {
80 char *name = boollist[i]->name;
81 int active = boollist[i]->active;
82 rc = sepol_bool_key_create(avc->handle, name, &key);
83 if (rc < 0) {
84 PyErr_SetString( PyExc_RuntimeError,
85 "Could not create boolean key.\n");
86 break;
87 }
88 rc = sepol_bool_query(avc->handle,
89 avc->policydb,
90 key, &boolean);
91
92 if (rc < 0) {
93 snprintf(errormsg, sizeof(errormsg),
94 "Could not find boolean %s.\n", name);
95 PyErr_SetString( PyExc_RuntimeError, errormsg);
96 break;
97 }
98
99 sepol_bool_set_value(boolean, !active);
100
101 rc = sepol_bool_set(avc->handle,
102 avc->policydb,
103 key, boolean);
104 if (rc < 0) {
105 snprintf(errormsg, sizeof(errormsg),
106 "Could not set boolean data %s.\n", name);
107 PyErr_SetString( PyExc_RuntimeError, errormsg);
108 break;
109 }
110
111 /* Reproduce the computation. */
112 rc = sepol_compute_av_reason(avc->ssid, avc->tsid, avc->tclass,
113 avc->av, &avd, &reason);
114 if (rc < 0) {
115 snprintf(errormsg, sizeof(errormsg),
116 "Error during access vector computation, skipping...");
117 PyErr_SetString( PyExc_RuntimeError, errormsg);
118
119 sepol_bool_free(boolean);
120 break;
121 } else {
122 if (!reason) {
123 foundlist[fcnt] = i;
124 fcnt++;
125 }
126 sepol_bool_set_value(boolean, active);
127 rc = sepol_bool_set(avc->handle,
128 avc->policydb, key,
129 boolean);
130 if (rc < 0) {
131 snprintf(errormsg, sizeof(errormsg),
132 "Could not set boolean data %s.\n",
133 name);
134
135 PyErr_SetString( PyExc_RuntimeError, errormsg);
136 break;
137 }
138 }
139 sepol_bool_free(boolean);
140 sepol_bool_key_free(key);
141 key = NULL;
142 boolean = NULL;
143 }
144 if (key)
145 sepol_bool_key_free(key);
146
147 if (boolean)
148 sepol_bool_free(boolean);
149
150 if (fcnt > 0) {
151 *bools = calloc(sizeof(struct boolean_t), fcnt + 1);
152 struct boolean_t *b = *bools;
153 for (i = 0; i < fcnt; i++) {
154 int ctr = foundlist[i];
155 b[i].name = strdup(boollist[ctr]->name);
156 b[i].active = !boollist[ctr]->active;
157 }
158 }
159 free(foundlist);
160 return fcnt;
161 }
162
finish(PyObject * self,PyObject * args)163 static PyObject *finish(PyObject *self __attribute__((unused)), PyObject *args) {
164 PyObject *result = 0;
165
166 if (PyArg_ParseTuple(args,(char *)":finish")) {
167 int i = 0;
168 if (! avc)
169 Py_RETURN_NONE;
170
171 for (i = 0; i < boolcnt; i++) {
172 free(boollist[i]->name);
173 free(boollist[i]);
174 }
175 free(boollist);
176 sepol_sidtab_shutdown(&sidtab);
177 sepol_sidtab_destroy(&sidtab);
178 sepol_policydb_free(avc->policydb);
179 sepol_handle_destroy(avc->handle);
180 free(avc);
181 avc = NULL;
182 boollist = NULL;
183 boolcnt = 0;
184
185 /* Boilerplate to return "None" */
186 Py_RETURN_NONE;
187 }
188 return result;
189 }
190
191
__policy_init(const char * init_path)192 static int __policy_init(const char *init_path)
193 {
194 FILE *fp;
195 char path[PATH_MAX];
196 char errormsg[PATH_MAX+1024+20];
197 struct sepol_policy_file *pf = NULL;
198 int rc;
199 unsigned int cnt;
200
201 path[PATH_MAX-1] = '\0';
202 if (init_path) {
203 strncpy(path, init_path, PATH_MAX-1);
204 fp = fopen(path, "re");
205 if (!fp) {
206 snprintf(errormsg, sizeof(errormsg),
207 "unable to open %s: %m\n",
208 path);
209 PyErr_SetString( PyExc_ValueError, errormsg);
210 return 1;
211 }
212 } else {
213 const char *curpolicy = selinux_current_policy_path();
214 if (!curpolicy) {
215 /* SELinux disabled, must use -p option. */
216 snprintf(errormsg, sizeof(errormsg),
217 "You must specify the -p option with the path to the policy file.\n");
218 PyErr_SetString( PyExc_ValueError, errormsg);
219 return 1;
220 }
221 fp = fopen(curpolicy, "re");
222 if (!fp) {
223 snprintf(errormsg, sizeof(errormsg),
224 "unable to open %s: %m\n",
225 curpolicy);
226 PyErr_SetString( PyExc_ValueError, errormsg);
227 return 1;
228 }
229 }
230
231 avc = calloc(sizeof(struct avc_t), 1);
232 if (!avc) {
233 PyErr_SetString( PyExc_MemoryError, "Out of memory\n");
234 fclose(fp);
235 return 1;
236 }
237
238 /* Set up a policydb directly so that we can mutate it later
239 for testing what booleans might have allowed the access.
240 Otherwise, we'd just use sepol_set_policydb_from_file() here. */
241 if (sepol_policy_file_create(&pf) ||
242 sepol_policydb_create(&avc->policydb)) {
243 snprintf(errormsg, sizeof(errormsg),
244 "policydb_init failed: %m\n");
245 PyErr_SetString( PyExc_RuntimeError, errormsg);
246 fclose(fp);
247 return 1;
248 }
249 sepol_policy_file_set_fp(pf, fp);
250 if (sepol_policydb_read(avc->policydb, pf)) {
251 snprintf(errormsg, sizeof(errormsg),
252 "invalid binary policy %s\n", path);
253 PyErr_SetString( PyExc_ValueError, errormsg);
254 fclose(fp);
255 return 1;
256 }
257 fclose(fp);
258 sepol_set_policydb(&avc->policydb->p);
259 avc->handle = sepol_handle_create();
260 /* Turn off messages */
261 sepol_msg_set_callback(avc->handle, NULL, NULL);
262
263 rc = sepol_bool_count(avc->handle,
264 avc->policydb, &cnt);
265 if (rc < 0) {
266 PyErr_SetString( PyExc_RuntimeError, "unable to get bool count\n");
267 return 1;
268 }
269
270 boollist = calloc(cnt, sizeof(*boollist));
271 if (!boollist) {
272 PyErr_SetString( PyExc_MemoryError, "Out of memory\n");
273 return 1;
274 }
275
276 sepol_bool_iterate(avc->handle, avc->policydb,
277 load_booleans, NULL);
278
279 /* Initialize the sidtab for subsequent use by sepol_context_to_sid
280 and sepol_compute_av_reason. */
281 rc = sepol_sidtab_init(&sidtab);
282 if (rc < 0) {
283 PyErr_SetString( PyExc_RuntimeError, "unable to init sidtab\n");
284 free(boollist);
285 return 1;
286 }
287 sepol_set_sidtab(&sidtab);
288 return 0;
289 }
290
init(PyObject * self,PyObject * args)291 static PyObject *init(PyObject *self __attribute__((unused)), PyObject *args) {
292 int result;
293 char *init_path = NULL;
294 if (avc) {
295 PyErr_SetString( PyExc_RuntimeError, "init called multiple times");
296 return NULL;
297 }
298 if (!PyArg_ParseTuple(args,(char *)"|s:policy_init",&init_path))
299 return NULL;
300 result = __policy_init(init_path);
301 return Py_BuildValue("i", result);
302 }
303
304 #define RETURN(X) \
305 { \
306 return Py_BuildValue("iO", (X), Py_None); \
307 }
308
analyze(PyObject * self,PyObject * args)309 static PyObject *analyze(PyObject *self __attribute__((unused)) , PyObject *args) {
310 char *reason_buf = NULL;
311 char * scon;
312 char * tcon;
313 char *tclassstr;
314 PyObject *listObj;
315 PyObject *strObj;
316 int numlines;
317 struct boolean_t *bools;
318 unsigned int reason;
319 sepol_security_id_t ssid, tsid;
320 sepol_security_class_t tclass;
321 sepol_access_vector_t perm, av;
322 struct sepol_av_decision avd;
323 int rc;
324 int i = 0;
325
326 if (!PyArg_ParseTuple(args,(char *)"sssO!:audit2why",&scon,&tcon,&tclassstr,&PyList_Type, &listObj))
327 return NULL;
328
329 /* get the number of lines passed to us */
330 numlines = PyList_Size(listObj);
331
332 /* should raise an error here. */
333 if (numlines < 0) return NULL; /* Not a list */
334
335 if (!avc)
336 RETURN(NOPOLICY)
337
338 rc = sepol_context_to_sid(scon, strlen(scon) + 1, &ssid);
339 if (rc < 0)
340 RETURN(BADSCON)
341
342 rc = sepol_context_to_sid(tcon, strlen(tcon) + 1, &tsid);
343 if (rc < 0)
344 RETURN(BADTCON)
345
346 rc = sepol_string_to_security_class(tclassstr, &tclass);
347 if (rc < 0)
348 RETURN(BADTCLASS)
349
350 /* Convert the permission list to an AV. */
351 av = 0;
352
353 /* iterate over items of the list, grabbing strings, and parsing
354 for numbers */
355 for (i = 0; i < numlines; i++){
356 const char *permstr;
357
358 /* grab the string object from the next element of the list */
359 strObj = PyList_GetItem(listObj, i); /* Can't fail */
360
361 /* make it a string */
362 #if PY_MAJOR_VERSION >= 3
363 permstr = _PyUnicode_AsString( strObj );
364 #else
365 permstr = PyString_AsString( strObj );
366 #endif
367
368 rc = sepol_string_to_av_perm(tclass, permstr, &perm);
369 if (rc < 0)
370 RETURN(BADPERM)
371
372 av |= perm;
373 }
374
375 /* Reproduce the computation. */
376 rc = sepol_compute_av_reason_buffer(ssid, tsid, tclass, av, &avd, &reason, &reason_buf, 0);
377 if (rc < 0)
378 RETURN(BADCOMPUTE)
379
380 if (!reason)
381 RETURN(ALLOW)
382
383 if (reason & SEPOL_COMPUTEAV_TE) {
384 avc->ssid = ssid;
385 avc->tsid = tsid;
386 avc->tclass = tclass;
387 avc->av = av;
388 if (check_booleans(&bools) == 0) {
389 if (av & ~avd.auditdeny) {
390 RETURN(DONTAUDIT)
391 } else {
392 RETURN(TERULE)
393 }
394 } else {
395 PyObject *outboollist;
396 struct boolean_t *b = bools;
397 int len = 0;
398 while (b->name) {
399 len++; b++;
400 }
401 b = bools;
402 outboollist = PyList_New(len);
403 len = 0;
404 while(b->name) {
405 PyObject *bool_ = Py_BuildValue("(si)", b->name, b->active);
406 PyList_SetItem(outboollist, len++, bool_);
407 b++;
408 }
409 free(bools);
410 /* 'N' steals the reference to outboollist */
411 return Py_BuildValue("iN", BOOLEAN, outboollist);
412 }
413 }
414
415 if (reason & SEPOL_COMPUTEAV_CONS) {
416 if (reason_buf) {
417 PyObject *result = NULL;
418 result = Py_BuildValue("is", CONSTRAINT, reason_buf);
419 free(reason_buf);
420 return result;
421 }
422 RETURN(CONSTRAINT)
423 }
424
425 if (reason & SEPOL_COMPUTEAV_RBAC)
426 RETURN(RBAC)
427
428 if (reason & SEPOL_COMPUTEAV_BOUNDS)
429 RETURN(BOUNDS)
430
431 RETURN(BADCOMPUTE)
432 }
433
434 static PyMethodDef audit2whyMethods[] = {
435 {"init", init, METH_VARARGS,
436 "Initialize policy database."},
437 {"analyze", analyze, METH_VARARGS,
438 "Analyze AVC."},
439 {"finish", finish, METH_VARARGS,
440 "Finish using policy, free memory."},
441 {NULL, NULL, 0, NULL} /* Sentinel */
442 };
443
444 #if PY_MAJOR_VERSION >= 3
445 /* Module-initialization logic specific to Python 3 */
446 static struct PyModuleDef moduledef = {
447 PyModuleDef_HEAD_INIT,
448 "audit2why",
449 NULL,
450 0,
451 audit2whyMethods,
452 NULL,
453 NULL,
454 NULL,
455 NULL
456 };
457
458 PyMODINIT_FUNC PyInit_audit2why(void); /* silence -Wmissing-prototypes */
PyInit_audit2why(void)459 PyMODINIT_FUNC PyInit_audit2why(void)
460 #else
461 PyMODINIT_FUNC initaudit2why(void); /* silence -Wmissing-prototypes */
462 PyMODINIT_FUNC initaudit2why(void)
463 #endif
464 {
465 PyObject *m;
466 #if PY_MAJOR_VERSION >= 3
467 m = PyModule_Create(&moduledef);
468 if (m == NULL) {
469 return NULL;
470 }
471 #else
472 m = Py_InitModule("audit2why", audit2whyMethods);
473 #endif
474 PyModule_AddIntConstant(m,"UNKNOWN", UNKNOWN);
475 PyModule_AddIntConstant(m,"BADSCON", BADSCON);
476 PyModule_AddIntConstant(m,"BADTCON", BADTCON);
477 PyModule_AddIntConstant(m,"BADTCLASS", BADTCLASS);
478 PyModule_AddIntConstant(m,"BADPERM", BADPERM);
479 PyModule_AddIntConstant(m,"BADCOMPUTE", BADCOMPUTE);
480 PyModule_AddIntConstant(m,"NOPOLICY", NOPOLICY);
481 PyModule_AddIntConstant(m,"ALLOW", ALLOW);
482 PyModule_AddIntConstant(m,"DONTAUDIT", DONTAUDIT);
483 PyModule_AddIntConstant(m,"TERULE", TERULE);
484 PyModule_AddIntConstant(m,"BOOLEAN", BOOLEAN);
485 PyModule_AddIntConstant(m,"CONSTRAINT", CONSTRAINT);
486 PyModule_AddIntConstant(m,"RBAC", RBAC);
487 PyModule_AddIntConstant(m,"BOUNDS", BOUNDS);
488
489 #if PY_MAJOR_VERSION >= 3
490 return m;
491 #endif
492 }
493