1 /* 2 * Copyright (c) 2017 Fujitsu Ltd. 3 * Author: Xiao Yang <yangx.jy (at) cn.fujitsu.com> 4 * 5 * This program is free software: you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License as published by 7 * the Free Software Foundation, either version 2 of the License, or 8 * (at your option) any later version. 9 * 10 * This program is distributed in the hope that it will be useful, 11 * but WITHOUT ANY WARRANTY; without even the implied warranty of 12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 * 15 * You should have received a copy of the GNU General Public License 16 * along with this program. If not, see <http://www.gnu.org/licenses/>.* 17 */ 18 19 /* 20 * Description: 21 * fcntl(2) manpage states that an unprivileged user could not set the 22 * pipe capacity above the limit in /proc/sys/fs/pipe-max-size. However, 23 * an unprivileged user could create a pipe whose initial capacity exceeds 24 * the limit. We add a regression test to check that pipe-max-size caps 25 * the initial allocation for a new pipe for unprivileged users, but not 26 * for privileged users. 27 * 28 * This kernel bug has been fixed by: 29 * 30 * commit 086e774a57fba4695f14383c0818994c0b31da7c 31 * Author: Michael Kerrisk (man-pages) <mtk.manpages (at) gmail.com> 32 * Date: Tue Oct 11 13:53:43 2016 -0700 33 * 34 * pipe: cap initial pipe capacity according to pipe-max-size limit 35 */ 36 37 #include <errno.h> 38 #include <sys/types.h> 39 #include <pwd.h> 40 #include <unistd.h> 41 #include <fcntl.h> 42 #include <stdlib.h> 43 44 #include "lapi/fcntl.h" 45 #include "tst_test.h" 46 47 static int pipe_max_unpriv; 48 static int test_max_unpriv; 49 static int test_max_priv; 50 static struct passwd *pw; 51 static struct tcase { 52 int *exp_sz; 53 int exp_usr; 54 char *des; 55 } tcases[] = { 56 {&test_max_unpriv, 1, "an unprivileged user"}, 57 {&test_max_priv, 0, "a privileged user"} 58 }; 59 60 static void setup(void) 61 { 62 test_max_unpriv = getpagesize(); 63 test_max_priv = test_max_unpriv * 16; 64 65 if (!access("/proc/sys/fs/pipe-max-size", F_OK)) { 66 SAFE_FILE_SCANF("/proc/sys/fs/pipe-max-size", "%d", 67 &pipe_max_unpriv); 68 SAFE_FILE_PRINTF("/proc/sys/fs/pipe-max-size", "%d", 69 test_max_unpriv); 70 } else { 71 tst_brk(TCONF, "/proc/sys/fs/pipe-max-size doesn't exist"); 72 } 73 74 pw = SAFE_GETPWNAM("nobody"); 75 } 76 77 static void cleanup(void) 78 { 79 SAFE_FILE_PRINTF("/proc/sys/fs/pipe-max-size", "%d", pipe_max_unpriv); 80 } 81 82 static int verify_pipe_size(int exp_pip_sz, char *desp) 83 { 84 int get_size; 85 int fds[2]; 86 87 SAFE_PIPE(fds); 88 89 get_size = fcntl(fds[1], F_GETPIPE_SZ); 90 if (get_size == -1) { 91 tst_res(TFAIL | TERRNO, "fcntl(2) with F_GETPIPE_SZ failed"); 92 goto end; 93 } 94 95 if (get_size != exp_pip_sz) { 96 tst_res(TFAIL, "%s init the capacity of a pipe to %d " 97 "unexpectedly, expected %d", desp, get_size, 98 exp_pip_sz); 99 } else { 100 tst_res(TPASS, "%s init the capacity of a pipe to %d " 101 "successfully", desp, exp_pip_sz); 102 } 103 104 end: 105 if (fds[0] > 0) 106 SAFE_CLOSE(fds[0]); 107 108 if (fds[1] > 0) 109 SAFE_CLOSE(fds[1]); 110 111 exit(0); 112 } 113 114 static void do_test(unsigned int n) 115 { 116 struct tcase *tc = &tcases[n]; 117 118 if (!SAFE_FORK()) { 119 if (tc->exp_usr) 120 SAFE_SETUID(pw->pw_uid); 121 122 verify_pipe_size(*tc->exp_sz, tc->des); 123 } 124 125 tst_reap_children(); 126 } 127 128 static struct tst_test test = { 129 .min_kver = "2.6.35", 130 .needs_root = 1, 131 .forks_child = 1, 132 .tcnt = ARRAY_SIZE(tcases), 133 .setup = setup, 134 .cleanup = cleanup, 135 .test = do_test 136 }; 137
