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/param.h> 30 #include <sys/random.h> 31 #include <errno.h> 32 33 #include <atf-c.h> 34 35 #include <zstd.h> 36 37 static const unsigned valid_flags[] = { 0, GRND_NONBLOCK, GRND_RANDOM, 38 GRND_NONBLOCK | GRND_RANDOM }; 39 40 ATF_TC_WITHOUT_HEAD(getrandom_randomness); 41 ATF_TC_BODY(getrandom_randomness, tc) 42 { 43 char randomb[4096], compressed[5000]; 44 ssize_t ret; 45 size_t i, j, c; 46 unsigned mode; 47 48 for (i = 0; i < nitems(valid_flags); i++) { 49 mode = valid_flags[i]; 50 51 /* Get new random data, filling randomb. */ 52 53 memset(randomb, 0, sizeof(randomb)); 54 55 for (j = 0; j < sizeof(randomb);) { 56 ret = getrandom(&randomb[j], sizeof(randomb) - j, mode); 57 if (ret < 0 && (mode & GRND_NONBLOCK) != 0 && 58 errno == EAGAIN) 59 continue; 60 61 ATF_REQUIRE_MSG(ret >= 0, "other error: %d", errno); 62 ATF_REQUIRE_MSG(ret > 0, "bogus zero return"); 63 64 j += (size_t)ret; 65 } 66 67 /* Perform compressibility test */ 68 c = ZSTD_compress(compressed, sizeof(compressed), randomb, 69 sizeof(randomb), ZSTD_maxCLevel()); 70 ATF_REQUIRE_MSG(!ZSTD_isError(c), "zstd compress: %s", 71 ZSTD_getErrorName(c)); 72 73 /* 74 * If the output is very compressible, it's probably not random 75 */ 76 ATF_REQUIRE_MSG(c > (sizeof(randomb) * 4 / 5), 77 "purportedly random data was compressible: %zu/%zu or %f%%", 78 c, sizeof(randomb), (double)c / (double)sizeof(randomb)); 79 } 80 } 81 82 ATF_TC_WITHOUT_HEAD(getrandom_fault); 83 ATF_TC_BODY(getrandom_fault, tc) 84 { 85 ssize_t ret; 86 87 ret = getrandom(NULL, 1, 0); 88 ATF_REQUIRE_EQ(ret, -1); 89 ATF_REQUIRE_EQ(errno, EFAULT); 90 } 91 92 ATF_TC_WITHOUT_HEAD(getrandom_count); 93 ATF_TC_BODY(getrandom_count, tc) 94 { 95 char buf[4096], reference[4096]; 96 ssize_t ret; 97 98 /* getrandom(2) does not modify buf past the requested length */ 99 _Static_assert(sizeof(reference) == sizeof(buf), "must match"); 100 memset(reference, 0x7C, sizeof(reference)); 101 102 memset(buf, 0x7C, sizeof(buf)); 103 ret = getrandom(buf, 1, 0); 104 ATF_REQUIRE_EQ(ret, 1); 105 ATF_REQUIRE_EQ(memcmp(&buf[1], reference, sizeof(reference) - 1), 0); 106 107 memset(buf, 0x7C, sizeof(buf)); 108 ATF_REQUIRE_EQ(getrandom(buf, 15, 0), 15); 109 ATF_REQUIRE_EQ(memcmp(&buf[15], reference, sizeof(reference) - 15), 0); 110 111 memset(buf, 0x7C, sizeof(buf)); 112 ATF_REQUIRE_EQ(getrandom(buf, 255, 0), 255); 113 ATF_REQUIRE_EQ(memcmp(&buf[255], reference, sizeof(reference) - 255), 0); 114 115 memset(buf, 0x7C, sizeof(buf)); 116 ATF_REQUIRE_EQ(getrandom(buf, 4095, 0), 4095); 117 ATF_REQUIRE_EQ(memcmp(&buf[4095], reference, sizeof(reference) - 4095), 0); 118 } 119 120 ATF_TP_ADD_TCS(tp) 121 { 122 123 ATF_TP_ADD_TC(tp, getrandom_count); 124 ATF_TP_ADD_TC(tp, getrandom_fault); 125 ATF_TP_ADD_TC(tp, getrandom_randomness); 126 return (atf_no_error()); 127 } 128