Memory violation in coap

[mkmik]

make -C test test_asan TEST_FILTER=coap

CC  unit_test_asan
RUN unit_test_asan coap
=================================================================
==15382==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7fff5ab81fc3 at pc 0x000105144d93 bp 0x7fff5ab80c70 sp 0x7fff5ab80c68
READ of size 1 at 0x7fff5ab81fc3 thread T0
    #0 0x105144d92 in coap_get_options /Users/mkm/Projects/cesanta/fossa/test/src/coap.c:246:3
    #1 0x105142b54 in ns_coap_parse /Users/mkm/Projects/cesanta/fossa/test/src/coap.c:348:14
    #2 0x1050a79e9 in test_coap /Users/mkm/Projects/cesanta/fossa/test/unit_test.c:2212:9
    #3 0x105083348 in run_tests /Users/mkm/Projects/cesanta/fossa/test/unit_test.c:2487:3
    #4 0x10507df16 in main /Users/mkm/Projects/cesanta/fossa/test/unit_test.c:2497:14
    #5 0x7fff8eda65fc in start (/usr/lib/system/libdyld.dylib+0x35fc)
    #6 0x1 (<unknown module>)

Address 0x7fff5ab81fc3 is located in stack of thread T0 at offset 323 in frame
    #0 0x1050a549f in test_coap /Users/mkm/Projects/cesanta/fossa/test/unit_test.c:2115

  This frame has 24 object(s):
    [32, 40) 'retval'
    [64, 88) 'packet_in'
    [128, 152) 'packet_out'
    [192, 256) 'cm'
    [288, 292) 'res'
    [304, 323) 'coap_packet_1' <== Memory access at offset 323 overflows this variable
    [368, 372) 'coap_packet_2'
    [384, 513) 'coap_packet_3'
    [592, 596) 'coap_packet_4'
    [608, 638) 'coap_packet_5'
    [672, 676) 'coap_packet_6'
    [688, 718) 'coap_packet_7'
    [752, 756) 'coap_packet_2_broken'
    [768, 772) 'coap_packet_2_broken1098'
    [784, 786) 'value16'
    [800, 832) 'mgr'
    [864, 872) 'nc'
    [896, 904) 'address'
    [928, 936) 'res1488'
    [960, 992) 'mgr1489'
    [1024, 1032) 'nc1'
    [1056, 1064) 'nc2'
    [1088, 1096) 'address1490'
    [1120, 1124) 'i'
HINT: this may be a false positive if your program uses some custom stack unwind mechanism or swapcontext
      (longjmp and C++ exceptions *are* supported)
SUMMARY: AddressSanitizer: stack-buffer-overflow /Users/mkm/Projects/cesanta/fossa/test/src/coap.c:246 coap_get_options
Shadow bytes around the buggy address:
  0x1fffeb5703a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1fffeb5703b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1fffeb5703c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1fffeb5703d0: f1 f1 f1 f1 00 f2 f2 f2 00 00 00 f2 f2 f2 f2 f2
  0x1fffeb5703e0: 00 00 00 f2 f2 f2 f2 f2 00 00 00 00 00 00 00 00
=>0x1fffeb5703f0: f2 f2 f2 f2 04 f2 00 00[03]f2 f2 f2 f2 f2 04 f2
  0x1fffeb570400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x1fffeb570410: 01 f2 f2 f2 f2 f2 f2 f2 f2 f2 04 f2 00 00 00 06
  0x1fffeb570420: f2 f2 f2 f2 04 f2 00 00 00 06 f2 f2 f2 f2 04 f2
  0x1fffeb570430: 04 f2 02 f2 00 00 00 00 f2 f2 f2 f2 00 f2 f2 f2
  0x1fffeb570440: 00 f2 f2 f2 00 f2 f2 f2 00 00 00 00 f2 f2 f2 f2
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
  Heap right redzone:      fb
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack partial redzone:   f4
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  ASan internal:           fe
==15382==ABORTING
make: *** [test_asan] Error 1