ASAN reports "stack buffer over flow"

[JaylinYu]

Describe the bug
ASAN complains

Expected behavior
Runs forever

Actual Behavior
==382476==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ffff03f8bd0 at pc 0x7ffff75f9fb9 bp 0x7ffff33fdca0 sp 0x7ffff33fd448
READ of size 2 at 0x7ffff03f8bd0 thread T1
#0 0x7ffff75f9fb8 in read_iovec ../../../../src/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:1013
#1 0x7ffff763c4ec in read_msghdr ../../../../src/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:3082
#2 0x7ffff763dcf5 in __interceptor_sendmsg ../../../../src/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:3099
#3 0x5555559bfc55 in tcp_dowrite /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/platform/posix/posix_tcpconn.c:69
#4 0x5555559c09f9 in tcp_cb /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/platform/posix/posix_tcpconn.c:245
#5 0x55555564d9ed in nni_posix_poll_thr /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/platform/posix/posix_pollq_epoll.c:291
#6 0x555555642bc5 in nni_thr_wrap /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/core/thread.c:94
#7 0x55555564bd7a in nni_plat_thr_main /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/platform/posix/posix_thread.c:266
#8 0x7ffff6f49b42 in start_thread nptl/pthread_create.c:442
#9 0x7ffff6fdb9ff (/lib/x86_64-linux-gnu/libc.so.6+0x1269ff)

Address 0x7ffff03f8bd0 is located in stack of thread T7 at offset 112 in frame
#0 0x55555560bd74 in server_cb /home/jaylin/Projects/EdgeComputing/nanomq/nanomq/apps/broker.c:225

This frame has 3 object(s):
[32, 40) 'msg' (line 227)
[64, 72) 'decode_msg' (line 280)
[96, 104) 'rep_msg' (line 403) <== Memory access at offset 112 overflows this variable
HINT: this may be a false positive if your program uses some custom stack unwind mechanism, swapcontext or vfork
(longjmp and C++ exceptions are supported)
Thread T7 created by T0 here:
#0 0x7ffff7616685 in __interceptor_pthread_create ../../../../src/libsanitizer/asan/asan_interceptors.cpp:216
#1 0x55555564beaa in nni_plat_thr_init /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/platform/posix/posix_thread.c:279
#2 0x555555642e71 in nni_thr_init /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/core/thread.c:121
#3 0x555555641b2f in nni_taskq_init /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/core/taskq.c:95
#4 0x55555564288f in nni_taskq_sys_init /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/core/taskq.c:294
#5 0x55555562c70e in nni_init_helper /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/core/init.c:35
#6 0x55555564c24f in nni_plat_init /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/platform/posix/posix_thread.c:422
#7 0x55555562c78f in nni_init /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/core/init.c:58
#8 0x55555569592a in nng_mtx_alloc /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/supplemental/util/platform.c:93
#9 0x5555555e0616 in log_init /home/jaylin/Projects/EdgeComputing/nanomq/nanomq/mqtt_api.c:223
#10 0x55555561590a in broker_start /home/jaylin/Projects/EdgeComputing/nanomq/nanomq/apps/broker.c:1565
#11 0x5555555e09bf in main /home/jaylin/Projects/EdgeComputing/nanomq/nanomq/nanomq.c:142
#12 0x7ffff6eded8f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58

SUMMARY: AddressSanitizer: stack-buffer-overflow ../../../../src/libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:1013 in read_iovec
Shadow bytes around the buggy address:
0x10007e077120: 00 00 00 00 f1 f1 f1 f1 00 f2 f2 f2 00 00 f3 f3
0x10007e077130: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x10007e077140: 00 00 f1 f1 f1 f1 00 f3 f3 f3 00 00 00 00 00 00
0x10007e077150: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x10007e077160: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
=>0x10007e077170: 00 f2 f2 f2 00 f2 f2 f2 00 f3[f3]f3 00 00 00 00
0x10007e077180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x10007e077190: 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00
0x10007e0771a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 f3 f3
0x10007e0771b0: f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x10007e0771c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
Addressable: 00
Partially addressable: 01 02 03 04 05 06 07
Heap left redzone: fa
Freed heap region: fd
Stack left redzone: f1
Stack mid redzone: f2
Stack right redzone: f3
Stack after return: f5
Stack use after scope: f8
Global redzone: f9
Global init order: f6
Poisoned by user: f7
Container overflow: fc
Array cookie: ac
Intra object redzone: bb
ASan internal: fe
Left alloca redzone: ca
Right alloca redzone: cb
Shadow gap: cc
Thread T1 created by T0 here:
#0 0x7ffff7616685 in __interceptor_pthread_create ../../../../src/libsanitizer/asan/asan_interceptors.cpp:216
#1 0x55555564beaa in nni_plat_thr_init /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/platform/posix/posix_thread.c:279
#2 0x555555642e71 in nni_thr_init /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/core/thread.c:121
#3 0x55555564e309 in nni_posix_pollq_create /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/platform/posix/posix_pollq_epoll.c:386
#4 0x55555564e3f9 in nni_posix_pollq_sysinit /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/platform/posix/posix_pollq_epoll.c:400
#5 0x55555564c13b in nni_plat_init /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/platform/posix/posix_thread.c:396
#6 0x55555562c78f in nni_init /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/core/init.c:58
#7 0x55555569592a in nng_mtx_alloc /home/jaylin/Projects/EdgeComputing/nanomq/nng/src/supplemental/util/platform.c:93
#8 0x5555555e0616 in log_init /home/jaylin/Projects/EdgeComputing/nanomq/nanomq/mqtt_api.c:223
#9 0x55555561590a in broker_start /home/jaylin/Projects/EdgeComputing/nanomq/nanomq/apps/broker.c:1565
#10 0x5555555e09bf in main /home/jaylin/Projects/EdgeComputing/nanomq/nanomq/nanomq.c:142
#11 0x7ffff6eded8f in __libc_start_call_main ../sysdeps/nptl/libc_start_call_main.h:58

==382476==ABORTING

To Reproduce
emqtt_bench pub -c 10 -i 5 -I 100 -p 1883 -t wangha/1 -s 40480
bridge nanomq to remote broker on topic wangha/1

** Environment Details **

• NanoMQ version 0.14.1
• Operating system and version Ubuntu 22