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==7016==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x615000000280 at pc 0x00000054e1e4 bp 0x7ffdf438ab70 sp 0x7ffdf438ab68
READ of size 4 at 0x615000000280 thread T0
#0 0x54e1e3 in md_is_link_reference_definition_helper /home/ubuntu/fuzz/test/md4c/md4c/md4c.c:1931:33
#1 0x5320d5 in md_is_link_reference_definition /home/ubuntu/fuzz/test/md4c/md4c/md4c.c:2213:11
#2 0x5320d5 in md_consume_link_reference_definitions /home/ubuntu/fuzz/test/md4c/md4c/md4c.c:4648
#3 0x5320d5 in md_end_current_block /home/ubuntu/fuzz/test/md4c/md4c/md4c.c:4694
#4 0x52c7f7 in md_process_doc /home/ubuntu/fuzz/test/md4c/md4c/md4c.c:5850:5
#5 0x5202cb in md_parse /home/ubuntu/fuzz/test/md4c/md4c/md4c.c:5917:11
#6 0x51a7a8 in md_render_html /home/ubuntu/fuzz/test/md4c/md2html/render_html.c:488:12
#7 0x5195cc in process_file /home/ubuntu/fuzz/test/md4c/md2html/md2html.c:139:11
#8 0x5195cc in main /home/ubuntu/fuzz/test/md4c/md2html/md2html.c:343
#9 0x7f20771c082f in __libc_start_main /build/glibc-Cl5G7W/glibc-2.23/csu/../csu/libc-start.c:291
#10 0x41a668 in _start (/home/ubuntu/fuzz/test/md4c/build/md2html/md2html+0x41a668)
0x615000000280 is located 0 bytes to the right of 512-byte region [0x615000000080,0x615000000280)
allocated by thread T0 here:
#0 0x4ded00 in realloc /home/ubuntu/llvm/llvm-6.0.0.src/projects/compiler-rt/lib/asan/asan_malloc_linux.cc:107
#1 0x527b65 in md_push_block_bytes /home/ubuntu/fuzz/test/md4c/md4c/md4c.c:4560:27
#2 0x527b65 in md_start_new_block /home/ubuntu/fuzz/test/md4c/md4c/md4c.c:4587
#3 0x527b65 in md_process_line /home/ubuntu/fuzz/test/md4c/md4c/md4c.c:5820
#4 0x527b65 in md_process_doc /home/ubuntu/fuzz/test/md4c/md4c/md4c.c:5847
#5 0x5202cb in md_parse /home/ubuntu/fuzz/test/md4c/md4c/md4c.c:5917:11
#6 0x51a7a8 in md_render_html /home/ubuntu/fuzz/test/md4c/md2html/render_html.c:488:12
#7 0x5195cc in process_file /home/ubuntu/fuzz/test/md4c/md2html/md2html.c:139:11
#8 0x5195cc in main /home/ubuntu/fuzz/test/md4c/md2html/md2html.c:343
#9 0x7f20771c082f in __libc_start_main /build/glibc-Cl5G7W/glibc-2.23/csu/../csu/libc-start.c:291
SUMMARY: AddressSanitizer: heap-buffer-overflow /home/ubuntu/fuzz/test/md4c/md4c/md4c.c:1931:33 in md_is_link_reference_definition_helper
Shadow bytes around the buggy address:
0x0c2a7fff8000: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c2a7fff8010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c2a7fff8020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c2a7fff8030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0x0c2a7fff8040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0c2a7fff8050:[fa]fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c2a7fff8060: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c2a7fff8070: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c2a7fff8080: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c2a7fff8090: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x0c2a7fff80a0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
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
==7016==ABORTING
command: ./md2html testfile
testcase: https://github.com/ChijinZ/security_advisories/blob/master/md4c-387bd02/crash_md_is_link_reference_definition_helper
AddressSanitizer provided information as below: