1 /* $NetBSD: t_mprotect.c,v 1.4 2016/05/28 14:34:49 christos Exp $ */
4 * Copyright (c) 2011 The NetBSD Foundation, Inc.
7 * This code is derived from software contributed to The NetBSD Foundation
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
31 #include <sys/cdefs.h>
32 __RCSID("$NetBSD: t_mprotect.c,v 1.4 2016/05/28 14:34:49 christos Exp $");
34 #include <sys/param.h>
36 #include <sys/sysctl.h>
47 #include "../common/exec_prot.h"
50 static int pax_global = -1;
51 static int pax_enabled = -1;
52 static char path[] = "mmap";
54 static void sighandler(int);
55 static bool paxinit(void);
56 static bool paxset(int, int);
67 size_t len = sizeof(int);
70 rv = sysctlbyname("security.pax.mprotect.global",
71 &pax_global, &len, NULL, 0);
76 rv = sysctlbyname("security.pax.mprotect.enabled",
77 &pax_enabled, &len, NULL, 0);
83 paxset(int global, int enabled)
85 size_t len = sizeof(int);
88 rv = sysctlbyname("security.pax.mprotect.global",
89 NULL, NULL, &global, len);
94 rv = sysctlbyname("security.pax.mprotect.enabled",
95 NULL, NULL, &enabled, len);
104 ATF_TC_WITH_CLEANUP(mprotect_access);
105 ATF_TC_HEAD(mprotect_access, tc)
107 atf_tc_set_md_var(tc, "descr", "Test for EACCES from mprotect(2)");
110 ATF_TC_BODY(mprotect_access, tc)
112 int prot[2] = { PROT_NONE, PROT_READ };
117 fd = open(path, O_RDONLY | O_CREAT);
118 ATF_REQUIRE(fd >= 0);
121 * The call should fail with EACCES if we try to mark
122 * a PROT_NONE or PROT_READ file/section as PROT_WRITE.
124 for (i = 0; i < __arraycount(prot); i++) {
126 map = mmap(NULL, page, prot[i], MAP_SHARED, fd, 0);
128 if (map == MAP_FAILED)
133 ATF_REQUIRE(mprotect(map, page, PROT_WRITE) != 0);
134 ATF_REQUIRE(errno == EACCES);
135 ATF_REQUIRE(munmap(map, page) == 0);
138 ATF_REQUIRE(close(fd) == 0);
141 ATF_TC_CLEANUP(mprotect_access, tc)
146 ATF_TC(mprotect_err);
147 ATF_TC_HEAD(mprotect_err, tc)
149 atf_tc_set_md_var(tc, "descr", "Test error conditions of mprotect(2)");
152 ATF_TC_BODY(mprotect_err, tc)
156 ATF_REQUIRE(mprotect((char *)-1, 1, PROT_READ) != 0);
157 ATF_REQUIRE(errno == EINVAL);
160 ATF_TC(mprotect_exec);
161 ATF_TC_HEAD(mprotect_exec, tc)
163 atf_tc_set_md_var(tc, "descr",
164 "Test mprotect(2) executable space protections");
168 * Trivial function -- should fit into a page
170 ATF_TC_BODY(mprotect_exec, tc)
176 xp_support = exec_prot_support();
178 switch (xp_support) {
181 "Execute protection callback check not implemented");
185 "Host does not support executable space protection");
187 case PARTIAL_XP: case PERPAGE_XP: default:
193 if (pax_enabled == 1 && pax_global == 1)
194 atf_tc_skip("PaX MPROTECT restrictions enabled");
198 * Map a page read/write and copy a trivial assembly function inside.
199 * We will then change the mapping rights:
200 * - first by setting the execution right, and check that we can
201 * call the code found in the allocated page.
202 * - second by removing the execution right. This should generate
203 * a SIGSEGV on architectures that can enforce --x permissions.
206 map = mmap(NULL, page, PROT_WRITE|PROT_READ, MAP_ANON, -1, 0);
207 ATF_REQUIRE(map != MAP_FAILED);
209 memcpy(map, (void *)return_one,
210 (uintptr_t)return_one_end - (uintptr_t)return_one);
212 /* give r-x rights then call code in page */
213 ATF_REQUIRE(mprotect(map, page, PROT_EXEC|PROT_READ) == 0);
214 ATF_REQUIRE(((int (*)(void))map)() == 1);
216 /* remove --x right */
217 ATF_REQUIRE(mprotect(map, page, PROT_READ) == 0);
220 ATF_REQUIRE(pid >= 0);
223 ATF_REQUIRE(signal(SIGSEGV, sighandler) != SIG_ERR);
224 ATF_CHECK(((int (*)(void))map)() == 1);
230 ATF_REQUIRE(munmap(map, page) == 0);
232 ATF_REQUIRE(WIFEXITED(sta) != 0);
234 switch (xp_support) {
236 /* Partial protection might fail; skip the test when it does */
237 if (WEXITSTATUS(sta) != SIGSEGV) {
238 atf_tc_skip("Host only supports "
239 "partial executable space protection");
242 case PERPAGE_XP: default:
243 /* Per-page --x protection should not fail */
244 ATF_REQUIRE(WEXITSTATUS(sta) == SIGSEGV);
249 ATF_TC(mprotect_pax);
250 ATF_TC_HEAD(mprotect_pax, tc)
252 atf_tc_set_md_var(tc, "descr", "PaX restrictions and mprotect(2)");
253 atf_tc_set_md_var(tc, "require.user", "root");
256 ATF_TC_BODY(mprotect_pax, tc)
258 const int prot[4] = { PROT_NONE, PROT_READ, PROT_WRITE };
259 const char *str = NULL;
264 if (!paxinit() || !paxset(1, 1))
268 * As noted in the original PaX documentation [1],
269 * the following restrictions should apply:
271 * (1) creating executable anonymous mappings
273 * (2) creating executable/writable file mappings
275 * (3) making a non-executable mapping executable
277 * (4) making an executable/read-only file mapping
278 * writable except for performing relocations
279 * on an ET_DYN ELF file (non-PIC shared library)
281 * The following will test only the case (3).
283 * [1] http://pax.grsecurity.net/docs/mprotect.txt
285 * (Sun Apr 3 11:06:53 EEST 2011.)
287 for (i = 0; i < __arraycount(prot); i++) {
289 map = mmap(NULL, page, prot[i], MAP_ANON, -1, 0);
291 if (map == MAP_FAILED)
294 rv = mprotect(map, 1, prot[i] | PROT_EXEC);
296 (void)munmap(map, page);
299 str = "non-executable mapping made executable";
305 if (pax_global != -1 && pax_enabled != -1)
306 (void)paxset(pax_global, pax_enabled);
309 atf_tc_fail("%s", str);
312 ATF_TC(mprotect_write);
313 ATF_TC_HEAD(mprotect_write, tc)
315 atf_tc_set_md_var(tc, "descr", "Test mprotect(2) write protections");
318 ATF_TC_BODY(mprotect_write, tc)
325 * Map a page read/write, change the protection
326 * to read-only with mprotect(2), and try to write
327 * to the page. This should generate a SIGSEGV.
329 map = mmap(NULL, page, PROT_WRITE|PROT_READ, MAP_ANON, -1, 0);
330 ATF_REQUIRE(map != MAP_FAILED);
332 ATF_REQUIRE(strlcpy(map, "XXX", 3) == 3);
333 ATF_REQUIRE(mprotect(map, page, PROT_READ) == 0);
336 ATF_REQUIRE(pid >= 0);
339 ATF_REQUIRE(signal(SIGSEGV, sighandler) != SIG_ERR);
340 ATF_REQUIRE(strlcpy(map, "XXX", 3) == 0);
345 ATF_REQUIRE(WIFEXITED(sta) != 0);
346 ATF_REQUIRE(WEXITSTATUS(sta) == SIGSEGV);
347 ATF_REQUIRE(munmap(map, page) == 0);
352 page = sysconf(_SC_PAGESIZE);
353 ATF_REQUIRE(page >= 0);
355 ATF_TP_ADD_TC(tp, mprotect_access);
356 ATF_TP_ADD_TC(tp, mprotect_err);
357 ATF_TP_ADD_TC(tp, mprotect_exec);
358 ATF_TP_ADD_TC(tp, mprotect_pax);
359 ATF_TP_ADD_TC(tp, mprotect_write);
361 return atf_no_error();