1 /*
2 * Check decoding of kcmp syscall.
3 *
4 * Copyright (c) 2016-2017 Eugene Syromyatnikov <evgsyr@gmail.com>
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30 #include "tests.h"
31
32 #include <asm/unistd.h>
33 #include "scno.h"
34
35 #ifdef __NR_kcmp
36
37 # include <fcntl.h>
38 # include <stdarg.h>
39 # include <stdint.h>
40 # include <stdio.h>
41 # include <string.h>
42 # include <unistd.h>
43
44 # ifndef VERBOSE_FD
45 # define VERBOSE_FD 0
46 # endif
47
48 /*
49 * We prefer to use system headers in order to catch some possible deviations in
50 * system's headers from our perception of reality, but happy to include our own
51 * definitions as well.
52 */
53 # ifdef HAVE_LINUX_KCMP_H
54 # include <linux/kcmp.h>
55 # else
56 # define KCMP_FILE 0
57 # define KCMP_VM 1
58 # define KCMP_FILES 2
59 # define KCMP_FS 3
60 # define KCMP_SIGHAND 4
61 # define KCMP_IO 5
62 # define KCMP_SYSVSEM 6
63 # endif
64
65 /* All other kcmp types have been added atomically */
66 # define KCMP_EPOLL_TFD 7
67
68 # ifndef HAVE_STRUCT_KCMP_EPOLL_SLOT
69 struct kcmp_epoll_slot {
70 uint32_t efd;
71 uint32_t tfd;
72 uint32_t toff;
73 };
74 # endif
75
76 static const kernel_ulong_t kcmp_max_type = KCMP_EPOLL_TFD;
77
78 static const char null_path[] = "/dev/null";
79 static const char zero_path[] = "/dev/zero";
80
81 # define NULL_FD 23
82 # define ZERO_FD 42
83
84 static void
printpidfd(const char * prefix,pid_t pid,unsigned fd)85 printpidfd(const char *prefix, pid_t pid, unsigned fd)
86 {
87 printf("%s%d", prefix, fd);
88 }
89
90 /*
91 * Last argument is optional and is used as follows:
92 * * When type is KCMP_EPOLL_TFD, it signalises whether idx2 is a valid
93 * pointer.
94 */
95 static void
do_kcmp(kernel_ulong_t pid1,kernel_ulong_t pid2,kernel_ulong_t type,const char * type_str,kernel_ulong_t idx1,kernel_ulong_t idx2,...)96 do_kcmp(kernel_ulong_t pid1, kernel_ulong_t pid2, kernel_ulong_t type,
97 const char *type_str, kernel_ulong_t idx1, kernel_ulong_t idx2, ...)
98 {
99 long rc;
100 const char *errstr;
101
102 rc = syscall(__NR_kcmp, pid1, pid2, type, idx1, idx2);
103 errstr = sprintrc(rc);
104
105 printf("kcmp(%d, %d, ", (int) pid1, (int) pid2);
106
107 if (type_str)
108 printf("%s", type_str);
109 else
110 printf("%#x /* KCMP_??? */", (int) type);
111
112 if (type == KCMP_FILE) {
113 printpidfd(", ", pid1, idx1);
114 printpidfd(", ", pid2, idx2);
115 } else if (type == KCMP_EPOLL_TFD) {
116 va_list ap;
117 int valid_ptr;
118
119 va_start(ap, idx2);
120 valid_ptr = va_arg(ap, int);
121 va_end(ap);
122
123 printpidfd(", ", pid1, idx1);
124 printf(", ");
125
126 if (valid_ptr) {
127 struct kcmp_epoll_slot *slot =
128 (struct kcmp_epoll_slot *) (uintptr_t) idx2;
129
130 printpidfd("{efd=", pid2, slot->efd);
131 printpidfd(", tfd=", pid2, slot->tfd);
132 printf(", toff=%llu}", (unsigned long long) slot->toff);
133 } else {
134 if (idx2)
135 printf("%#llx", (unsigned long long) idx2);
136 else
137 printf("NULL");
138 }
139 } else if (type > kcmp_max_type) {
140 printf(", %#llx, %#llx",
141 (unsigned long long) idx1, (unsigned long long) idx2);
142 }
143
144 printf(") = %s\n", errstr);
145 }
146
147 int
main(void)148 main(void)
149 {
150 static const kernel_ulong_t bogus_pid1 =
151 (kernel_ulong_t) 0xdeadca75face1057ULL;
152 static const kernel_ulong_t bogus_pid2 =
153 (kernel_ulong_t) 0xdefaced1defaced2ULL;
154 static const kernel_ulong_t bogus_type =
155 (kernel_ulong_t) 0xbadc0dedda7adeadULL;
156 static const kernel_ulong_t bogus_idx1 =
157 (kernel_ulong_t) 0xdec0ded3dec0ded4ULL;
158 static const kernel_ulong_t bogus_idx2 =
159 (kernel_ulong_t) 0xba5e1e55deadc0deULL;
160 static const struct kcmp_epoll_slot slot_data[] = {
161 { 0xdeadc0de, 0xfacef157, 0xbadc0ded },
162 { NULL_FD, ZERO_FD, 0 },
163 { 0, 0, 0 },
164 };
165 static kernel_ulong_t ptr_check =
166 F8ILL_KULONG_SUPPORTED ? F8ILL_KULONG_MASK : 0;
167
168 int fd;
169 unsigned i;
170 struct kcmp_epoll_slot *slot = tail_alloc(sizeof(*slot));
171
172 /* Open some files to test printpidfd */
173 fd = open(null_path, O_RDONLY);
174 if (fd < 0)
175 perror_msg_and_fail("open(\"%s\")", null_path);
176 if (fd != NULL_FD) {
177 if (dup2(fd, NULL_FD) < 0)
178 perror_msg_and_fail("dup2(fd, NULL_FD)");
179 close(fd);
180 }
181
182 fd = open(zero_path, O_RDONLY);
183 if (fd < 0)
184 perror_msg_and_fail("open(\"%s\")", zero_path);
185 if (fd != ZERO_FD) {
186 if (dup2(fd, ZERO_FD) < 0)
187 perror_msg_and_fail("dup2(fd, ZERO_FD)");
188 close(fd);
189 }
190
191 close(0);
192
193 /* Invalid values */
194 do_kcmp(bogus_pid1, bogus_pid2, bogus_type, NULL, bogus_idx1,
195 bogus_idx2);
196 do_kcmp(F8ILL_KULONG_MASK, F8ILL_KULONG_MASK, kcmp_max_type + 1, NULL,
197 0, 0);
198
199 /* KCMP_FILE is the only type which has additional args */
200 do_kcmp(3141592653U, 2718281828U, ARG_STR(KCMP_FILE), bogus_idx1,
201 bogus_idx2);
202 do_kcmp(-1, -1, ARG_STR(KCMP_FILE), NULL_FD, ZERO_FD);
203
204 /* Types without additional args */
205 do_kcmp(-1, -1, ARG_STR(KCMP_VM), bogus_idx1, bogus_idx2);
206 do_kcmp(-1, -1, ARG_STR(KCMP_FILES), bogus_idx1, bogus_idx2);
207 do_kcmp(-1, -1, ARG_STR(KCMP_FS), bogus_idx1, bogus_idx2);
208 do_kcmp(-1, -1, ARG_STR(KCMP_SIGHAND), bogus_idx1, bogus_idx2);
209 do_kcmp(-1, -1, ARG_STR(KCMP_IO), bogus_idx1, bogus_idx2);
210 do_kcmp(-1, -1, ARG_STR(KCMP_SYSVSEM), bogus_idx1, bogus_idx2);
211
212 /* KCMP_EPOLL_TFD checks */
213 do_kcmp(-1, -1, ARG_STR(KCMP_EPOLL_TFD),
214 F8ILL_KULONG_MASK | 2718281828U, ptr_check, 0);
215 do_kcmp(-1, -1, ARG_STR(KCMP_EPOLL_TFD),
216 3141592653U, (uintptr_t) slot + 1, 0);
217
218 for (i = 0; i < ARRAY_SIZE(slot_data); i++) {
219 memcpy(slot, slot_data + i, sizeof(*slot));
220
221 do_kcmp(getpid(), getppid(), ARG_STR(KCMP_EPOLL_TFD), NULL_FD,
222 (uintptr_t) slot, 1);
223 }
224
225 puts("+++ exited with 0 +++");
226
227 return 0;
228 }
229
230 #else
231
232 SKIP_MAIN_UNDEFINED("__NR_kcmp");
233
234 #endif
235