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/***************************************************************************
* _ _ ____ _
* Project ___| | | | _ \| |
* / __| | | | |_) | |
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 2019, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
* are also available at https://curl.haxx.se/docs/copyright.html.
*
* You may opt to use, copy, modify, merge, publish, distribute and/or sell
* copies of the Software, and permit persons to whom the Software is
* furnished to do so, under the terms of the COPYING file.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
***************************************************************************/
#include "curlcheck.h"
#include "doh.h" /* from the lib dir */
static CURLcode unit_setup(void)
{
/* whatever you want done first */
return CURLE_OK;
}
static void unit_stop(void)
{
/* done before shutting down and exiting */
}
UNITTEST_START
/* introduce a scope and prove the corner case with write overflow,
* so we can prove this test would detect it and that it is properly fixed
*/
do {
const char *bad = "this.is.a.hostname.where.each.individual.part.is.within."
"the.sixtythree.character.limit.but.still.long.enough.to."
"trigger.the.the.buffer.overflow......it.is.chosen.to.be."
"of.a.length.such.that.it.causes.a.two.byte.buffer......."
"overwrite.....making.it.longer.causes.doh.encode.to....."
".return.early.so.dont.change.its.length.xxxx.xxxxxxxxxxx"
"..xxxxxx.....xx..........xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx"
"xxxxxxxxxxxxxxxxxxxxxxxxxx.xxxxxxxxxxxxxxxx..x......xxxx"
"xxxx..xxxxxxxxxxxxxxxxxxx.x...xxxx.x.x.x...xxxxx";
/* plays the role of struct dnsprobe in urldata.h */
struct demo {
unsigned char dohbuffer[512];
unsigned char canary1;
unsigned char canary2;
unsigned char canary3;
};
size_t olen = 100000;
struct demo victim;
DOHcode d;
victim.canary1 = 87; /* magic numbers, arbritrarily picked */
victim.canary2 = 35;
victim.canary3 = 41;
d = doh_encode(bad, DNS_TYPE_A, victim.dohbuffer,
sizeof(victim.dohbuffer), &olen);
fail_unless(victim.canary1 == 87, "one byte buffer overwrite has happened");
fail_unless(victim.canary2 == 35, "two byte buffer overwrite has happened");
fail_unless(victim.canary3 == 41,
"three byte buffer overwrite has happened");
if(d == DOH_OK) {
fail_unless(olen <= sizeof(victim.dohbuffer), "wrote outside bounds");
fail_unless(olen > strlen(bad), "unrealistic low size");
}
} while(0);
/* run normal cases and try to trigger buffer length related errors */
do {
DNStype dnstype = DNS_TYPE_A;
unsigned char buffer[128];
const size_t buflen = sizeof(buffer);
const size_t magic1 = 9765;
size_t olen1 = magic1;
const char *sunshine1 = "a.com";
const char *sunshine2 = "aa.com";
size_t olen2;
DOHcode ret2;
size_t olen;
DOHcode ret = doh_encode(sunshine1, dnstype, buffer, buflen, &olen1);
fail_unless(ret == DOH_OK, "sunshine case 1 should pass fine");
fail_if(olen1 == magic1, "olen has not been assigned properly");
fail_unless(olen1 > strlen(sunshine1), "bad out length");
/* add one letter, the response should be one longer */
olen2 = magic1;
ret2 = doh_encode(sunshine2, dnstype, buffer, buflen, &olen2);
fail_unless(ret2 == DOH_OK, "sunshine case 2 should pass fine");
fail_if(olen2 == magic1, "olen has not been assigned properly");
fail_unless(olen1 + 1 == olen2, "olen should grow with the hostname");
/* pass a short buffer, should fail */
ret = doh_encode(sunshine1, dnstype, buffer, olen1 - 1, &olen);
fail_if(ret == DOH_OK, "short buffer should have been noticed");
/* pass a minimum buffer, should succeed */
ret = doh_encode(sunshine1, dnstype, buffer, olen1, &olen);
fail_unless(ret == DOH_OK, "minimal length buffer should be long enough");
fail_unless(olen == olen1, "bad buffer length");
} while(0);
UNITTEST_STOP
|
