/* $NetBSD: dns_rdata_fromwire_text.c,v 1.6.2.1 2024/02/25 15:46:11 martin Exp $ */ /* * Copyright (C) Internet Systems Consortium, Inc. ("ISC") * * SPDX-License-Identifier: MPL-2.0 * * This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this * file, you can obtain one at https://mozilla.org/MPL/2.0/. * * See the COPYRIGHT file distributed with this work for additional * information regarding copyright ownership. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "fuzz.h" bool debug = false; /* * Fuzz input to dns_rdata_fromwire(). Then convert the result * to text, back to wire format, to multiline text, and back to wire * format again, checking for consistency throughout the sequence. */ static isc_mem_t *mctx = NULL; static isc_lex_t *lex = NULL; int LLVMFuzzerInitialize(int *argc __attribute__((unused)), char ***argv __attribute__((unused))) { isc_lexspecials_t specials; isc_mem_create(&mctx); CHECK(isc_lex_create(mctx, 64, &lex)); memset(specials, 0, sizeof(specials)); specials[0] = 1; specials['('] = 1; specials[')'] = 1; specials['"'] = 1; isc_lex_setspecials(lex, specials); isc_lex_setcomments(lex, ISC_LEXCOMMENT_DNSMASTERFILE); return (0); } static void nullmsg(dns_rdatacallbacks_t *cb, const char *fmt, ...) { va_list args; UNUSED(cb); if (debug) { va_start(args, fmt); vfprintf(stderr, fmt, args); fprintf(stderr, "\n"); va_end(args); } } int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) { char totext[64 * 1044 * 4]; dns_compress_t cctx; dns_decompress_t dctx; dns_rdatatype_t rdtype; dns_rdataclass_t rdclass; dns_rdatatype_t typelist[256] = { 1000 }; /* unknown */ dns_rdataclass_t classlist[] = { dns_rdataclass_in, dns_rdataclass_hs, dns_rdataclass_ch, dns_rdataclass_any, 60 }; dns_rdata_t rdata1 = DNS_RDATA_INIT, rdata2 = DNS_RDATA_INIT, rdata3 = DNS_RDATA_INIT; dns_rdatacallbacks_t callbacks; isc_buffer_t source, target; isc_result_t result; unsigned char fromtext[1024]; unsigned char fromwire[1024]; unsigned char towire[1024]; unsigned int classes = (sizeof(classlist) / sizeof(classlist[0])); unsigned int types = 1, flags, t; /* * First 2 bytes are used to select type and class. * dns_rdata_fromwire() only accepts input up to 2^16-1 octets. */ if (size < 2 || size > 0xffff + 2) { return (0); } /* * Append known types to list. */ for (t = 1; t <= 0x10000; t++) { char typebuf[256]; if (dns_rdatatype_ismeta(t)) { continue; } dns_rdatatype_format(t, typebuf, sizeof(typebuf)); if (strncmp(typebuf, "TYPE", 4) != 0) { /* Assert when we need to grow typelist. */ assert(types < sizeof(typelist) / sizeof(typelist[0])); typelist[types++] = t; } } /* * Random type and class from a limited set. */ rdtype = typelist[(*data++) % types]; size--; rdclass = classlist[(*data++) % classes]; size--; if (debug) { fprintf(stderr, "type=%u, class=%u\n", rdtype, rdclass); } dns_rdatacallbacks_init(&callbacks); callbacks.warn = callbacks.error = nullmsg; /* Disallow decompression as we are reading a packet */ dns_decompress_init(&dctx, -1, DNS_DECOMPRESS_NONE); isc_buffer_constinit(&source, data, size); isc_buffer_add(&source, size); isc_buffer_setactive(&source, size); isc_buffer_init(&target, fromwire, sizeof(fromwire)); /* * Reject invalid rdata. */ CHECK(dns_rdata_fromwire(&rdata1, rdclass, rdtype, &source, &dctx, 0, &target)); assert(rdata1.length == size); /* * Convert to text from wire. */ isc_buffer_init(&target, totext, sizeof(totext) - 1); result = dns_rdata_totext(&rdata1, NULL, &target); assert(result == ISC_R_SUCCESS); /* * Make debugging easier by NUL terminating. */ totext[isc_buffer_usedlength(&target)] = 0; /* * Convert to wire from text. */ isc_buffer_constinit(&source, totext, isc_buffer_usedlength(&target)); isc_buffer_add(&source, isc_buffer_usedlength(&target)); CHECK(isc_lex_openbuffer(lex, &source)); isc_buffer_init(&target, fromtext, sizeof(fromtext)); result = dns_rdata_fromtext(&rdata2, rdclass, rdtype, lex, dns_rootname, 0, mctx, &target, &callbacks); if (debug && result != ISC_R_SUCCESS) { fprintf(stderr, "'%s'\n", totext); } assert(result == ISC_R_SUCCESS); assert(rdata2.length == size); assert(!memcmp(rdata2.data, data, size)); /* * Convert to multi-line text from wire. */ isc_buffer_init(&target, totext, sizeof(totext)); flags = dns_master_styleflags(&dns_master_style_default); result = dns_rdata_tofmttext(&rdata1, dns_rootname, flags, 80 - 32, 4, "\n", &target); assert(result == ISC_R_SUCCESS); /* * Convert to wire from text. */ isc_buffer_constinit(&source, totext, isc_buffer_usedlength(&target)); isc_buffer_add(&source, isc_buffer_usedlength(&target)); CHECK(isc_lex_openbuffer(lex, &source)); isc_buffer_init(&target, fromtext, sizeof(fromtext)); result = dns_rdata_fromtext(&rdata3, rdclass, rdtype, lex, dns_rootname, 0, mctx, &target, &callbacks); assert(result == ISC_R_SUCCESS); assert(rdata3.length == size); assert(!memcmp(rdata3.data, data, size)); /* * Convert rdata back to wire. */ CHECK(dns_compress_init(&cctx, -1, mctx)); dns_compress_disable(&cctx); isc_buffer_init(&target, towire, sizeof(towire)); result = dns_rdata_towire(&rdata1, &cctx, &target); dns_compress_invalidate(&cctx); assert(result == ISC_R_SUCCESS); assert(target.used == size); assert(!memcmp(target.base, data, size)); return (0); }