/*
* Copyright (c) 2023 Apple Computer, Inc. All rights reserved.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_START@
*
* This file contains Original Code and/or Modifications of Original Code
* as defined in and that are subject to the Apple Public Source License
* Version 2.0 (the 'License'). You may not use this file except in
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
* Please see the License for the specific language governing rights and
* limitations under the License.
*
* @APPLE_OSREFERENCE_LICENSE_HEADER_END@
*/
#include <darwintest.h>
#include <fcntl.h>
#include <stdlib.h>
#include <spawn.h>
#include <string.h>
#include <unistd.h>
#include <sys/codesign.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/wait.h>
T_GLOBAL_META(
T_META_NAMESPACE("xnu.vm"),
T_META_RADAR_COMPONENT_NAME("xnu"),
T_META_RADAR_COMPONENT_VERSION("VM"));
T_DECL(vm_tainted_executable, "Test that a tainted executable gets killed", T_META_TAG_VM_PREFERRED)
{
char tmp_path[] = "/tmp/hell0-XXXXXX";
int fd1, fd2;
struct stat fs;
char *mapaddr1;
size_t fsize;
char *big_sp, *big_cp, *big_ep, *little_cp;
size_t little_len;
char *child_argv[2];
pid_t child_pid;
int child_status;
int cs_status;
T_SETUPBEGIN;
/* copy "./hello" to "/tmp/hell0" */
fd1 = open("./hello", O_RDONLY);
T_QUIET; T_ASSERT_POSIX_SUCCESS(fd1, "open(./hello)");
fd2 = mkstemp(tmp_path);
T_QUIET; T_ASSERT_POSIX_SUCCESS(fd2, "mkstemp(%s)", tmp_path);
T_QUIET; T_ASSERT_POSIX_SUCCESS(fstat(fd1, &fs), NULL);
fsize = (size_t)fs.st_size;
mapaddr1 = mmap(NULL, fsize, PROT_READ, MAP_FILE | MAP_PRIVATE, fd1, 0);
T_QUIET; T_ASSERT_NOTNULL(mapaddr1, NULL);
T_QUIET; T_ASSERT_POSIX_SUCCESS(write(fd2, mapaddr1, fsize), NULL);
/* change "hello, world!" to "hell0, world!" */
big_sp = &mapaddr1[0]; /* start pointer in "big" byte string */
big_ep = &mapaddr1[fsize]; /* end pointer in "big" byte string */
little_cp = "hello, world!"; /* little byte string */
little_len = strlen(little_cp); /* length of little byte string */
big_cp = big_sp; /* start pointer in "big" byte string */
for (;;) {
char zero = '0';
big_cp = memmem(big_cp, (size_t)(big_ep - big_cp),
little_cp, little_len);
if (big_cp == NULL) {
break;
}
T_LOG("found string at offset 0x%llx", (off_t) (big_cp - big_sp));
T_QUIET; T_ASSERT_POSIX_SUCCESS(pwrite(fd2, &zero, 1,
(big_cp - big_sp + 4)), NULL);
big_cp += little_len;
}
/* make the new binary "r-x" */
T_QUIET; T_ASSERT_POSIX_SUCCESS(fchmod(fd2, S_IRUSR | S_IXUSR), NULL);
/* cleanup */
T_QUIET; T_ASSERT_POSIX_SUCCESS(close(fd1), NULL);
T_QUIET; T_ASSERT_POSIX_SUCCESS(close(fd2), NULL);
T_QUIET; T_ASSERT_POSIX_SUCCESS(munmap(mapaddr1, fsize), NULL);
T_SETUPEND;
/* spawn the newly-tainted binary */
T_LOG("launching '%s'", tmp_path);
child_argv[0] = tmp_path;
child_argv[1] = NULL;
T_QUIET; T_ASSERT_POSIX_SUCCESS(posix_spawn(&child_pid, tmp_path, NULL, NULL, child_argv, NULL), NULL);
/* check our code-signing policy, assuming the child has same policy */
T_QUIET; T_ASSERT_POSIX_SUCCESS(csops(getpid(), CS_OPS_STATUS, &cs_status, sizeof(cs_status)), NULL);
T_LOG("parent %d cs status 0x%x CS_KILL:%s", getpid(), cs_status,
(cs_status & CS_KILL) ? "yes" : "no");
/* get child's exit status */
T_QUIET; T_ASSERT_POSIX_SUCCESS(waitpid(child_pid, &child_status, 0), NULL);
T_LOG("child %d exit status 0x%x", child_pid, child_status);
/* we no longer need our modified binary */
T_QUIET; T_ASSERT_POSIX_SUCCESS(unlink(tmp_path), NULL);
if (cs_status & CS_KILL) {
/* check that child got SIGKILL */
T_QUIET; T_ASSERT_TRUE(WIFSIGNALED(child_status), NULL);
T_QUIET; T_ASSERT_TRUE(WTERMSIG(child_status) == SIGKILL, NULL);
T_PASS("enforced process launched from modified binary got SIGKILL");
} else {
/* check that child exited with 0 */
T_QUIET; T_ASSERT_TRUE(WIFEXITED(child_status), NULL);
T_QUIET; T_ASSERT_TRUE(WEXITSTATUS(child_status) == 0, NULL);
T_PASS("non-enforced process launched from modified binary exited with 0");
}
}