bind9/bin/tools/dnstap-read.c
Michał Kępień 3549abe81d dnstap-read: clear buffer before expanding it
When printing a packet, dnstap-read checks whether its text form takes
up more than the 2048 bytes allocated for the output buffer by default.
If that is the case, the output buffer is automatically expanded, but
the truncated output is left in the buffer, resulting in malformed data
being printed.  Clear the output buffer before expanding it to prevent
this issue from occurring.
2019-06-28 12:43:51 +02:00

405 lines
9.1 KiB
C

/*
* Copyright (C) Internet Systems Consortium, Inc. ("ISC")
*
* 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 http://mozilla.org/MPL/2.0/.
*
* See the COPYRIGHT file distributed with this work for additional
* information regarding copyright ownership.
*/
/*
* Portions of this code were adapted from dnstap-ldns:
*
* Copyright (c) 2014 by Farsight Security, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <inttypes.h>
#include <stdbool.h>
#include <stdlib.h>
#include <isc/buffer.h>
#include <isc/commandline.h>
#include <isc/hex.h>
#include <isc/mem.h>
#include <isc/print.h>
#include <isc/string.h>
#include <isc/util.h>
#include <dns/dnstap.h>
#include <dns/fixedname.h>
#include <dns/masterdump.h>
#include <dns/message.h>
#include <dns/name.h>
#include <dns/result.h>
#include <protobuf-c/protobuf-c.h>
#include "lib/dns/dnstap.pb-c.h"
isc_mem_t *mctx = NULL;
bool memrecord = false;
bool printmessage = false;
bool hexmessage = false;
bool yaml = false;
const char *program = "dnstap-read";
#define CHECKM(op, msg) \
do { result = (op); \
if (result != ISC_R_SUCCESS) { \
fprintf(stderr, \
"%s: %s: %s\n", program, msg, \
isc_result_totext(result)); \
goto cleanup; \
} \
} while (0)
ISC_PLATFORM_NORETURN_PRE static void
fatal(const char *format, ...) ISC_PLATFORM_NORETURN_POST;
static void
fatal(const char *format, ...) {
va_list args;
fprintf(stderr, "%s: fatal: ", program);
va_start(args, format);
vfprintf(stderr, format, args);
va_end(args);
fprintf(stderr, "\n");
exit(1);
}
static void
usage(void) {
fprintf(stderr, "dnstap-read [-mpxy] [filename]\n");
fprintf(stderr, "\t-m\ttrace memory allocations\n");
fprintf(stderr, "\t-p\tprint the full DNS message\n");
fprintf(stderr, "\t-x\tuse hex format to print DNS message\n");
fprintf(stderr, "\t-y\tprint YAML format (implies -p)\n");
}
static void
print_dtdata(dns_dtdata_t *dt) {
isc_result_t result;
isc_buffer_t *b = NULL;
isc_buffer_allocate(mctx, &b, 2048);
if (b == NULL)
fatal("out of memory");
CHECKM(dns_dt_datatotext(dt, &b), "dns_dt_datatotext");
printf("%.*s\n", (int) isc_buffer_usedlength(b),
(char *) isc_buffer_base(b));
cleanup:
if (b != NULL)
isc_buffer_free(&b);
}
static void
print_hex(dns_dtdata_t *dt) {
isc_buffer_t *b = NULL;
isc_result_t result;
size_t textlen;
if (dt->msg == NULL) {
return;
}
textlen = (dt->msgdata.length * 2) + 1;
isc_buffer_allocate(mctx, &b, textlen);
if (b == NULL) {
fatal("out of memory");
}
result = isc_hex_totext(&dt->msgdata, 0, "", b);
CHECKM(result, "isc_hex_totext");
printf("%.*s\n", (int) isc_buffer_usedlength(b),
(char *) isc_buffer_base(b));
cleanup:
if (b != NULL)
isc_buffer_free(&b);
}
static void
print_packet(dns_dtdata_t *dt, const dns_master_style_t *style) {
isc_buffer_t *b = NULL;
isc_result_t result;
if (dt->msg != NULL) {
size_t textlen = 2048;
isc_buffer_allocate(mctx, &b, textlen);
if (b == NULL)
fatal("out of memory");
for (;;) {
isc_buffer_reserve(&b, textlen);
if (b == NULL)
fatal("out of memory");
result = dns_message_totext(dt->msg, style, 0, b);
if (result == ISC_R_NOSPACE) {
isc_buffer_clear(b);
textlen *= 2;
continue;
} else if (result == ISC_R_SUCCESS) {
printf("%.*s",
(int) isc_buffer_usedlength(b),
(char *) isc_buffer_base(b));
isc_buffer_free(&b);
} else {
isc_buffer_free(&b);
CHECKM(result, "dns_message_totext");
}
break;
}
}
cleanup:
if (b != NULL)
isc_buffer_free(&b);
}
static void
print_yaml(dns_dtdata_t *dt) {
Dnstap__Dnstap *frame = dt->frame;
Dnstap__Message *m = frame->message;
const ProtobufCEnumValue *ftype, *mtype;
static bool first = true;
ftype = protobuf_c_enum_descriptor_get_value(
&dnstap__dnstap__type__descriptor,
frame->type);
if (ftype == NULL)
return;
if (!first)
printf("---\n");
else
first = false;
printf("type: %s\n", ftype->name);
if (frame->has_identity)
printf("identity: %.*s\n", (int) frame->identity.len,
frame->identity.data);
if (frame->has_version)
printf("version: %.*s\n", (int) frame->version.len,
frame->version.data);
if (frame->type != DNSTAP__DNSTAP__TYPE__MESSAGE)
return;
printf("message:\n");
mtype = protobuf_c_enum_descriptor_get_value(
&dnstap__message__type__descriptor,
m->type);
if (mtype == NULL)
return;
printf(" type: %s\n", mtype->name);
if (!isc_time_isepoch(&dt->qtime)) {
char buf[100];
isc_time_formatISO8601(&dt->qtime, buf, sizeof(buf));
printf(" query_time: !!timestamp %s\n", buf);
}
if (!isc_time_isepoch(&dt->rtime)) {
char buf[100];
isc_time_formatISO8601(&dt->rtime, buf, sizeof(buf));
printf(" response_time: !!timestamp %s\n", buf);
}
if (dt->msgdata.base != NULL) {
printf(" message_size: %zub\n", (size_t) dt->msgdata.length);
} else
printf(" message_size: 0b\n");
if (m->has_socket_family) {
const ProtobufCEnumValue *type =
protobuf_c_enum_descriptor_get_value(
&dnstap__socket_family__descriptor,
m->socket_family);
if (type != NULL)
printf(" socket_family: %s\n", type->name);
}
printf(" socket_protocol: %s\n", dt->tcp ? "TCP" : "UDP");
if (m->has_query_address) {
ProtobufCBinaryData *ip = &m->query_address;
char buf[100];
(void)inet_ntop(ip->len == 4 ? AF_INET : AF_INET6,
ip->data, buf, sizeof(buf));
printf(" query_address: %s\n", buf);
}
if (m->has_response_address) {
ProtobufCBinaryData *ip = &m->response_address;
char buf[100];
(void)inet_ntop(ip->len == 4 ? AF_INET : AF_INET6,
ip->data, buf, sizeof(buf));
printf(" response_address: %s\n", buf);
}
if (m->has_query_port)
printf(" query_port: %u\n", m->query_port);
if (m->has_response_port)
printf(" response_port: %u\n", m->response_port);
if (m->has_query_zone) {
isc_result_t result;
dns_fixedname_t fn;
dns_name_t *name;
isc_buffer_t b;
dns_decompress_t dctx;
name = dns_fixedname_initname(&fn);
isc_buffer_init(&b, m->query_zone.data, m->query_zone.len);
isc_buffer_add(&b, m->query_zone.len);
dns_decompress_init(&dctx, -1, DNS_DECOMPRESS_NONE);
result = dns_name_fromwire(name, &b, &dctx, 0, NULL);
if (result == ISC_R_SUCCESS) {
printf(" query_zone: ");
dns_name_print(name, stdout);
printf("\n");
}
}
if (dt->msg != NULL) {
printf(" %s:\n", ((dt->type & DNS_DTTYPE_QUERY) != 0)
? "query_message_data"
: "response_message_data");
print_packet(dt, &dns_master_style_yaml);
printf(" %s: |\n", ((dt->type & DNS_DTTYPE_QUERY) != 0)
? "query_message"
: "response_message");
print_packet(dt, &dns_master_style_indent);
}
};
int
main(int argc, char *argv[]) {
isc_result_t result;
dns_message_t *message = NULL;
isc_buffer_t *b = NULL;
dns_dtdata_t *dt = NULL;
dns_dthandle_t *handle = NULL;
int rv = 0, ch;
while ((ch = isc_commandline_parse(argc, argv, "mpxy")) != -1) {
switch (ch) {
case 'm':
isc_mem_debugging |= ISC_MEM_DEBUGRECORD;
memrecord = true;
break;
case 'p':
printmessage = true;
break;
case 'x':
hexmessage = true;
break;
case 'y':
yaml = true;
dns_master_indentstr = " ";
dns_master_indent = 2;
break;
default:
usage();
exit(1);
}
}
argc -= isc_commandline_index;
argv += isc_commandline_index;
if (argc < 1)
fatal("no file specified");
RUNTIME_CHECK(isc_mem_create(0, 0, &mctx) == ISC_R_SUCCESS);
dns_result_register();
CHECKM(dns_dt_open(argv[0], dns_dtmode_file, mctx, &handle),
"dns_dt_openfile");
for (;;) {
isc_region_t input;
uint8_t *data;
size_t datalen;
result = dns_dt_getframe(handle, &data, &datalen);
if (result == ISC_R_NOMORE)
break;
else
CHECKM(result, "dns_dt_getframe");
input.base = data;
input.length = datalen;
if (b != NULL)
isc_buffer_free(&b);
isc_buffer_allocate(mctx, &b, 2048);
if (b == NULL)
fatal("out of memory");
result = dns_dt_parse(mctx, &input, &dt);
if (result != ISC_R_SUCCESS) {
isc_buffer_free(&b);
continue;
}
if (yaml) {
print_yaml(dt);
} else if (hexmessage) {
print_dtdata(dt);
print_hex(dt);
} else if (printmessage) {
print_dtdata(dt);
print_packet(dt, &dns_master_style_debug);
} else {
print_dtdata(dt);
}
dns_dtdata_free(&dt);
}
cleanup:
if (dt != NULL)
dns_dtdata_free(&dt);
if (handle != NULL)
dns_dt_close(&handle);
if (message != NULL)
dns_message_destroy(&message);
if (b != NULL)
isc_buffer_free(&b);
isc_mem_destroy(&mctx);
exit(rv);
}