1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 3 * 4 * Copyright (c) 2018 Conrad Meyer <cem@FreeBSD.org> 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 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 #include <sys/param.h> 31 #include <sys/random.h> 32 #include <errno.h> 33 34 #include <atf-c.h> 35 36 #include <zstd.h> 37 38 static const unsigned valid_flags[] = { 0, GRND_NONBLOCK, GRND_RANDOM, 39 GRND_NONBLOCK | GRND_RANDOM }; 40 41 ATF_TC_WITHOUT_HEAD(getrandom_randomness); 42 ATF_TC_BODY(getrandom_randomness, tc) 43 { 44 char randomb[4096], compressed[5000]; 45 ssize_t ret; 46 size_t i, j, c; 47 unsigned mode; 48 49 for (i = 0; i < nitems(valid_flags); i++) { 50 mode = valid_flags[i]; 51 52 /* Get new random data, filling randomb. */ 53 54 memset(randomb, 0, sizeof(randomb)); 55 56 for (j = 0; j < sizeof(randomb);) { 57 ret = getrandom(&randomb[j], sizeof(randomb) - j, mode); 58 if (ret < 0 && (mode & GRND_NONBLOCK) != 0 && 59 errno == EAGAIN) 60 continue; 61 62 ATF_REQUIRE_MSG(ret >= 0, "other error: %d", errno); 63 ATF_REQUIRE_MSG(ret > 0, "bogus zero return"); 64 65 j += (size_t)ret; 66 } 67 68 /* Perform compressibility test */ 69 c = ZSTD_compress(compressed, sizeof(compressed), randomb, 70 sizeof(randomb), ZSTD_maxCLevel()); 71 ATF_REQUIRE_MSG(!ZSTD_isError(c), "zstd compress: %s", 72 ZSTD_getErrorName(c)); 73 74 /* 75 * If the output is very compressible, it's probably not random 76 */ 77 ATF_REQUIRE_MSG(c > (sizeof(randomb) * 4 / 5), 78 "purportedly random data was compressible: %zu/%zu or %f%%", 79 c, sizeof(randomb), (double)c / (double)sizeof(randomb)); 80 } 81 } 82 83 ATF_TC_WITHOUT_HEAD(getrandom_fault); 84 ATF_TC_BODY(getrandom_fault, tc) 85 { 86 ssize_t ret; 87 88 ret = getrandom(NULL, 1, 0); 89 ATF_REQUIRE_EQ(ret, -1); 90 ATF_REQUIRE_EQ(errno, EFAULT); 91 } 92 93 ATF_TC_WITHOUT_HEAD(getrandom_count); 94 ATF_TC_BODY(getrandom_count, tc) 95 { 96 char buf[4096], reference[4096]; 97 ssize_t ret; 98 99 /* getrandom(2) does not modify buf past the requested length */ 100 _Static_assert(sizeof(reference) == sizeof(buf), "must match"); 101 memset(reference, 0x7C, sizeof(reference)); 102 103 memset(buf, 0x7C, sizeof(buf)); 104 ret = getrandom(buf, 1, 0); 105 ATF_REQUIRE_EQ(ret, 1); 106 ATF_REQUIRE_EQ(memcmp(&buf[1], reference, sizeof(reference) - 1), 0); 107 108 memset(buf, 0x7C, sizeof(buf)); 109 ATF_REQUIRE_EQ(getrandom(buf, 15, 0), 15); 110 ATF_REQUIRE_EQ(memcmp(&buf[15], reference, sizeof(reference) - 15), 0); 111 112 memset(buf, 0x7C, sizeof(buf)); 113 ATF_REQUIRE_EQ(getrandom(buf, 255, 0), 255); 114 ATF_REQUIRE_EQ(memcmp(&buf[255], reference, sizeof(reference) - 255), 0); 115 116 memset(buf, 0x7C, sizeof(buf)); 117 ATF_REQUIRE_EQ(getrandom(buf, 4095, 0), 4095); 118 ATF_REQUIRE_EQ(memcmp(&buf[4095], reference, sizeof(reference) - 4095), 0); 119 } 120 121 ATF_TP_ADD_TCS(tp) 122 { 123 124 ATF_TP_ADD_TC(tp, getrandom_count); 125 ATF_TP_ADD_TC(tp, getrandom_fault); 126 ATF_TP_ADD_TC(tp, getrandom_randomness); 127 return (atf_no_error()); 128 } 129