tests/zfs-tests/cmd/suid_write_to_file.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License (the "License").
   6  * You may not use this file except in compliance with the License.
   7  *
   8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
   9  * or https://opensource.org/licenses/CDDL-1.0.
  10  * See the License for the specific language governing permissions
  11  * and limitations under the License.
  12  *
  13  * When distributing Covered Code, include this CDDL HEADER in each
  14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  15  * If applicable, add the following below this CDDL HEADER, with the
  16  * fields enclosed by brackets "[]" replaced with your own identifying
  17  * information: Portions Copyright [yyyy] [name of copyright owner]
  18  *
  19  * CDDL HEADER END
  20  */
  21 /*
  22  * Copyright (c) 2019 by Tomohiro Kusumi. All rights reserved.
  23  */
  24
  25 #include <stdio.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <sys/types.h>
  29 #include <sys/stat.h>
  30 #include <unistd.h>
  31 #include <fcntl.h>
  32 #include <stdbool.h>
  33
  34 int
  35 main(int argc, char *argv[])
  36 {
  37         const char *name, *phase;
  38         mode_t extra;
  39         struct stat st;
  40
  41         if (argc < 3) {
  42                 fprintf(stderr, "Invalid argc\n");
  43                 exit(1);
  44         }
  45
  46         name = argv[1];
  47         if (strcmp(name, "SUID") == 0) {
  48                 extra = S_ISUID;
  49         } else if (strcmp(name, "SGID") == 0) {
  50                 extra = S_ISGID;
  51         } else if (strcmp(name, "SUID_SGID") == 0) {
  52                 extra = S_ISUID | S_ISGID;
  53         } else if (strcmp(name, "NONE") == 0) {
  54                 extra = 0;
  55         } else {
  56                 fprintf(stderr, "Invalid name %s\n", name);
  57                 exit(1);
  58         }
  59
  60         const char *testdir = getenv("TESTDIR");
  61         if (!testdir) {
  62                 fprintf(stderr, "getenv(TESTDIR)\n");
  63                 exit(1);
  64         }
  65
  66         umask(0);
  67         if (stat(testdir, &st) == -1 && mkdir(testdir, 0777) == -1) {
  68                 perror("mkdir");
  69                 exit(2);
  70         }
  71
  72         char fpath[1024];
  73         snprintf(fpath, sizeof (fpath), "%s/%s", testdir, name);
  74
  75
  76         phase = argv[2];
  77         if (strcmp(phase, "PRECRASH") == 0) {
  78
  79                 /* clean up last run */
  80                 unlink(fpath);
  81                 if (stat(fpath, &st) == 0) {
  82                         fprintf(stderr, "%s exists\n", fpath);
  83                         exit(3);
  84                 }
  85
  86                 int fd;
  87
  88                 fd = creat(fpath, 0777 | extra);
  89                 if (fd == -1) {
  90                         perror("creat");
  91                         exit(4);
  92                 }
  93                 close(fd);
  94
  95                 if (setuid(65534) == -1) {
  96                         perror("setuid");
  97                         exit(5);
  98                 }
  99
 100                 fd = open(fpath, O_RDWR);
 101                 if (fd == -1) {
 102                         perror("open");
 103                         exit(6);
 104                 }
 105
 106                 const char buf[] = "test";
 107                 if (write(fd, buf, sizeof (buf)) == -1) {
 108                         perror("write");
 109                         exit(7);
 110                 }
 111                 close(fd);
 112
 113         } else if (strcmp(phase, "REPLAY") == 0) {
 114                 /* created in PRECRASH run */
 115         } else {
 116                 fprintf(stderr, "Invalid phase %s\n", phase);
 117                 exit(1);
 118         }
 119
 120         if (stat(fpath, &st) == -1) {
 121                         perror("stat");
 122                         exit(8);
 123                 }
 124
 125         /* Verify SUID/SGID are dropped */
 126         mode_t res = st.st_mode & (0777 | S_ISUID | S_ISGID);
 127         if (res != 0777) {
 128                 fprintf(stderr, "stat(2) %o\n", res);
 129                 exit(9);
 130         }
 131
 132         return (0);
 133 }