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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - Fuzzer crashed while fuzzing Mosquitto lib"
href="https://bugs.llvm.org/show_bug.cgi?id=43435">43435</a>
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<th>Summary</th>
<td>Fuzzer crashed while fuzzing Mosquitto lib
</td>
</tr>
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<th>Product</th>
<td>compiler-rt
</td>
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<th>Version</th>
<td>unspecified
</td>
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<th>Hardware</th>
<td>PC
</td>
</tr>
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<th>OS</th>
<td>Linux
</td>
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<th>Status</th>
<td>NEW
</td>
</tr>
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<th>Severity</th>
<td>enhancement
</td>
</tr>
<tr>
<th>Priority</th>
<td>P
</td>
</tr>
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<th>Component</th>
<td>fuzzer
</td>
</tr>
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<th>Assignee</th>
<td>unassignedbugs@nondot.org
</td>
</tr>
<tr>
<th>Reporter</th>
<td>huangyu.hw@foxmail.com
</td>
</tr>
<tr>
<th>CC</th>
<td>llvm-bugs@lists.llvm.org
</td>
</tr></table>
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<pre>Hi,
Here comes a bug while fuzzing Mosquitto lib, I would like to know the solution
or the group/person I can contact.
Step1. compile the lib
#:~/fuzz/fuzzmqtt/mosquitto$ ls
about.html doc Makefile security
aclfile.example docker man SECURITY.md
appveyor.yml edl-v10 misc service
buildtest.py epl-v10 mosquitto.conf set-version.sh
ChangeLog.txt examples Mosquitto.podspec snap
client installer notice.html src
CMakeLists.txt lib pskfile.example test
compiling.txt libmosquitto.pc.in pwfile.example THANKS.txt
config.h libmosquittopp.pc.in readme.md travis-configure.sh
config.mk LICENSE.txt readme-tests.md travis-install.sh
CONTRIBUTING.md logo readme-windows.txt www
#:~/fuzz/fuzzmqtt/mosquitto$ sudo make install CC="clang -O2
-fno-omit-frame-pointer -g -fsanitize=address
-fsanitize-coverage=trace-pc-guard,trace-cmp,trace-gep,trace-div" -j2
Step2. compile the fuzzer
#:~/fuzz/fuzzmqtt/mosquitto/lib$ clang -g -O1 -fsanitize=fuzzer,address
mos_fuzzer.cc -o mos_fuzzer -lmosquitto
Step3. Run the fuzzer and got the bug
#~/fuzz/fuzzmqtt/mosquitto/lib$ ./mos_fuzzer
INFO: Seed: 106983829
INFO: Loaded 1 modules (2337 guards): 2337 [0x7f157cd816b0, 0x7f157cd83b34),
INFO: Loaded 1 modules (1 inline 8-bit counters): 1 [0x787f80, 0x787f81),
INFO: Loaded 1 PC tables (1 PCs): 1 [0x565af8,0x565b08),
ERROR: The size of coverage PC tables does not match the
number of instrumented PCs. This might be a compiler bug,
please contact the libFuzzer developers.
Also check <a class="bz_bug_link
bz_status_NEW "
title="NEW - make -fsanitize-coverage=pc-table friendly with -ffunction-sections -Wl,-gc-sections"
href="show_bug.cgi?id=34636">https://bugs.llvm.org/show_bug.cgi?id=34636</a>
for possible workarounds (tl;dr: don't use the old GNU ld)
The fuzzer code is as follow
#include "stdio.h"
#include "mosquitto.h"
#include "assert.h"
#include "stdint.h"
#include "stddef.h"
extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) {
bool clean_session = true;
struct mosquitto *mosq = NULL;
mosquitto_lib_init();
void *data_1=(void *)data;
mosq = mosquitto_new(NULL, clean_session, data_1);
mosquitto_destroy(mosq);
mosquitto_lib_cleanup();
return 0;
}
Thank you</pre>
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