xf.li | 6c8fc1e | 2023-08-12 00:11:09 -0700 | [diff] [blame^] | 1 | /*************************************************************************** |
| 2 | * _ _ ____ _ |
| 3 | * Project ___| | | | _ \| | |
| 4 | * / __| | | | |_) | | |
| 5 | * | (__| |_| | _ <| |___ |
| 6 | * \___|\___/|_| \_\_____| |
| 7 | * |
| 8 | * Copyright (C) 2019 - 2022, Daniel Stenberg, <daniel@haxx.se>, et al. |
| 9 | * |
| 10 | * This software is licensed as described in the file COPYING, which |
| 11 | * you should have received as part of this distribution. The terms |
| 12 | * are also available at https://curl.se/docs/copyright.html. |
| 13 | * |
| 14 | * You may opt to use, copy, modify, merge, publish, distribute and/or sell |
| 15 | * copies of the Software, and permit persons to whom the Software is |
| 16 | * furnished to do so, under the terms of the COPYING file. |
| 17 | * |
| 18 | * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY |
| 19 | * KIND, either express or implied. |
| 20 | * |
| 21 | * SPDX-License-Identifier: curl |
| 22 | * |
| 23 | ***************************************************************************/ |
| 24 | #include "curlcheck.h" |
| 25 | |
| 26 | #include "doh.h" /* from the lib dir */ |
| 27 | |
| 28 | static CURLcode unit_setup(void) |
| 29 | { |
| 30 | /* whatever you want done first */ |
| 31 | return CURLE_OK; |
| 32 | } |
| 33 | |
| 34 | static void unit_stop(void) |
| 35 | { |
| 36 | /* done before shutting down and exiting */ |
| 37 | } |
| 38 | |
| 39 | #ifndef CURL_DISABLE_DOH |
| 40 | |
| 41 | UNITTEST_START |
| 42 | |
| 43 | /* |
| 44 | * Prove detection of write overflow using a short buffer and a name |
| 45 | * of maximal valid length. |
| 46 | * |
| 47 | * Prove detection of other invalid input. |
| 48 | */ |
| 49 | do { |
| 50 | static const char max[] = |
| 51 | /* ..|....1.........2.........3.........4.........5.........6... */ |
| 52 | /* 3456789012345678901234567890123456789012345678901234567890123 */ |
| 53 | "this.is.a.maximum-length.hostname." /* 34: 34 */ |
| 54 | "with-no-label-of-greater-length-than-the-sixty-three-characters." |
| 55 | /* 64: 98 */ |
| 56 | "specified.in.the.RFCs." /* 22: 120 */ |
| 57 | "and.with.a.QNAME.encoding.whose.length.is.exactly." /* 50: 170 */ |
| 58 | "the.maximum.length.allowed." /* 27: 197 */ |
| 59 | "that.is.two-hundred.and.fifty-six." /* 34: 231 */ |
| 60 | "including.the.last.null." /* 24: 255 */ |
| 61 | ""; |
| 62 | static const char toolong[] = |
| 63 | /* ..|....1.........2.........3.........4.........5.........6... */ |
| 64 | /* 3456789012345678901234567890123456789012345678901234567890123 */ |
| 65 | "here.is.a.hostname.which.is.just.barely.too.long." /* 49: 49 */ |
| 66 | "to.be.encoded.as.a.QNAME.of.the.maximum.allowed.length." |
| 67 | /* 55: 104 */ |
| 68 | "which.is.256.including.a.final.zero-length.label." /* 49: 153 */ |
| 69 | "representing.the.root.node.so.that.a.name.with." /* 47: 200 */ |
| 70 | "a.trailing.dot.may.have.up.to." /* 30: 230 */ |
| 71 | "255.characters.never.more." /* 26: 256 */ |
| 72 | ""; |
| 73 | static const char emptylabel[] = |
| 74 | "this.is.an.otherwise-valid.hostname." |
| 75 | ".with.an.empty.label."; |
| 76 | static const char outsizelabel[] = |
| 77 | "this.is.an.otherwise-valid.hostname." |
| 78 | "with-a-label-of-greater-length-than-the-sixty-three-characters-" |
| 79 | "specified.in.the.RFCs."; |
| 80 | int i; |
| 81 | |
| 82 | struct test { |
| 83 | const char *name; |
| 84 | const DOHcode expected_result; |
| 85 | }; |
| 86 | |
| 87 | /* plays the role of struct dnsprobe in urldata.h */ |
| 88 | struct demo { |
| 89 | unsigned char dohbuffer[255 + 16]; /* deliberately short buffer */ |
| 90 | unsigned char canary1; |
| 91 | unsigned char canary2; |
| 92 | unsigned char canary3; |
| 93 | }; |
| 94 | |
| 95 | const struct test playlist[4] = { |
| 96 | { toolong, DOH_DNS_NAME_TOO_LONG }, /* expect early failure */ |
| 97 | { emptylabel, DOH_DNS_BAD_LABEL }, /* also */ |
| 98 | { outsizelabel, DOH_DNS_BAD_LABEL }, /* also */ |
| 99 | { max, DOH_OK } /* expect buffer overwrite */ |
| 100 | }; |
| 101 | |
| 102 | for(i = 0; i < (int)(sizeof(playlist)/sizeof(*playlist)); i++) { |
| 103 | const char *name = playlist[i].name; |
| 104 | size_t olen = 100000; |
| 105 | struct demo victim; |
| 106 | DOHcode d; |
| 107 | |
| 108 | victim.canary1 = 87; /* magic numbers, arbitrarily picked */ |
| 109 | victim.canary2 = 35; |
| 110 | victim.canary3 = 41; |
| 111 | d = doh_encode(name, DNS_TYPE_A, victim.dohbuffer, |
| 112 | sizeof(struct demo), /* allow room for overflow */ |
| 113 | &olen); |
| 114 | |
| 115 | fail_unless(d == playlist[i].expected_result, |
| 116 | "result returned was not as expected"); |
| 117 | if(d == playlist[i].expected_result) { |
| 118 | if(name == max) { |
| 119 | fail_if(victim.canary1 == 87, |
| 120 | "demo one-byte buffer overwrite did not happen"); |
| 121 | } |
| 122 | else { |
| 123 | fail_unless(victim.canary1 == 87, |
| 124 | "one-byte buffer overwrite has happened"); |
| 125 | } |
| 126 | fail_unless(victim.canary2 == 35, |
| 127 | "two-byte buffer overwrite has happened"); |
| 128 | fail_unless(victim.canary3 == 41, |
| 129 | "three-byte buffer overwrite has happened"); |
| 130 | } |
| 131 | else { |
| 132 | if(d == DOH_OK) { |
| 133 | fail_unless(olen <= sizeof(victim.dohbuffer), "wrote outside bounds"); |
| 134 | fail_unless(olen > strlen(name), "unrealistic low size"); |
| 135 | } |
| 136 | } |
| 137 | } |
| 138 | } while(0); |
| 139 | |
| 140 | /* run normal cases and try to trigger buffer length related errors */ |
| 141 | do { |
| 142 | DNStype dnstype = DNS_TYPE_A; |
| 143 | unsigned char buffer[128]; |
| 144 | const size_t buflen = sizeof(buffer); |
| 145 | const size_t magic1 = 9765; |
| 146 | size_t olen1 = magic1; |
| 147 | const char *sunshine1 = "a.com"; |
| 148 | const char *dotshine1 = "a.com."; |
| 149 | const char *sunshine2 = "aa.com"; |
| 150 | size_t olen2; |
| 151 | DOHcode ret2; |
| 152 | size_t olen; |
| 153 | |
| 154 | DOHcode ret = doh_encode(sunshine1, dnstype, buffer, buflen, &olen1); |
| 155 | fail_unless(ret == DOH_OK, "sunshine case 1 should pass fine"); |
| 156 | fail_if(olen1 == magic1, "olen has not been assigned properly"); |
| 157 | fail_unless(olen1 > strlen(sunshine1), "bad out length"); |
| 158 | |
| 159 | /* with a trailing dot, the response should have the same length */ |
| 160 | olen2 = magic1; |
| 161 | ret2 = doh_encode(dotshine1, dnstype, buffer, buflen, &olen2); |
| 162 | fail_unless(ret2 == DOH_OK, "dotshine case should pass fine"); |
| 163 | fail_if(olen2 == magic1, "olen has not been assigned properly"); |
| 164 | fail_unless(olen1 == olen2, "olen should not grow for a trailing dot"); |
| 165 | |
| 166 | /* add one letter, the response should be one longer */ |
| 167 | olen2 = magic1; |
| 168 | ret2 = doh_encode(sunshine2, dnstype, buffer, buflen, &olen2); |
| 169 | fail_unless(ret2 == DOH_OK, "sunshine case 2 should pass fine"); |
| 170 | fail_if(olen2 == magic1, "olen has not been assigned properly"); |
| 171 | fail_unless(olen1 + 1 == olen2, "olen should grow with the hostname"); |
| 172 | |
| 173 | /* pass a short buffer, should fail */ |
| 174 | ret = doh_encode(sunshine1, dnstype, buffer, olen1 - 1, &olen); |
| 175 | fail_if(ret == DOH_OK, "short buffer should have been noticed"); |
| 176 | |
| 177 | /* pass a minimum buffer, should succeed */ |
| 178 | ret = doh_encode(sunshine1, dnstype, buffer, olen1, &olen); |
| 179 | fail_unless(ret == DOH_OK, "minimal length buffer should be long enough"); |
| 180 | fail_unless(olen == olen1, "bad buffer length"); |
| 181 | } while(0); |
| 182 | UNITTEST_STOP |
| 183 | |
| 184 | #else /* CURL_DISABLE_DOH */ |
| 185 | |
| 186 | UNITTEST_START |
| 187 | { |
| 188 | return 1; /* nothing to do, just fail */ |
| 189 | } |
| 190 | UNITTEST_STOP |
| 191 | |
| 192 | #endif |