ubuntu@3d76fd667859:$ ./mruby $POC
=================================================================
==556970==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x503000000360 at pc 0x60b5ded21679 bp 0x7ffc20d6c1b0 sp 0x7ffc20d6c1a8
READ of size 4 at 0x503000000360 thread T0
#0 0x60b5ded21678 in mrb_vm_exec mruby-66606f71d/src/vm.c:2790:27
#1 0x60b5deceea68 in mrb_vm_run mruby-66606f71d/src/vm.c:1351:22
#2 0x60b5ded50eb4 in mrb_top_run mruby-66606f71d/src/vm.c:3101:10
#3 0x60b5ded9b9b2 in mrb_load_exec mruby-66606f71d/mrbgems/mruby-compiler/core/parse.y:6920:7
#4 0x60b5ded9c483 in mrb_load_detect_file_cxt mruby-66606f71d/mrbgems/mruby-compiler/core/parse.y:6963:12
#5 0x60b5dec0ace6 in main mruby-66606f71d/mrbgems/mruby-bin-mruby/tools/mruby/mruby.c:353:11
#6 0x7cb4e20a91c9 in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
#7 0x7cb4e20a928a in __libc_start_main csu/../csu/libc-start.c:360:3
#8 0x60b5deb30954 in _start (mruby+0xc3954) (BuildId: 0c748cfb61c0f80c654d51d81762fc9c22a26732)
0x503000000360 is located 0 bytes after 32-byte region [0x503000000340,0x503000000360)
allocated by thread T0 here:
#0 0x60b5debcbbc0 in realloc (mruby+0x15ebc0) (BuildId: 0c748cfb61c0f80c654d51d81762fc9c22a26732)
#1 0x60b5deddb6fa in mrb_default_allocf mruby-66606f71d/src/allocf.c:27:12
#2 0x60b5dec54c12 in mrb_realloc_simple mruby-66606f71d/src/gc.c:197:8
#3 0x60b5dee435fd in codegen_realloc mruby-66606f71d/mrbgems/mruby-compiler/core/codegen.c:165:7
#4 0x60b5dee5d191 in scope_finish mruby-66606f71d/mrbgems/mruby-compiler/core/codegen.c:4072:38
#5 0x60b5dee4e9ff in scope_body mruby-66606f71d/mrbgems/mruby-compiler/core/codegen.c:1658:3
#6 0x60b5dee33498 in codegen mruby-66606f71d/mrbgems/mruby-compiler/core/codegen.c:2807:5
#7 0x60b5dee2bf61 in generate_code mruby-66606f71d/mrbgems/mruby-compiler/core/codegen.c:4214:5
#8 0x60b5dee2ba81 in mrb_generate_code mruby-66606f71d/mrbgems/mruby-compiler/core/codegen.c:4237:10
#9 0x60b5ded9b052 in mrb_load_exec mruby-66606f71d/mrbgems/mruby-compiler/core/parse.y:6895:10
#10 0x60b5ded9c483 in mrb_load_detect_file_cxt mruby-66606f71d/mrbgems/mruby-compiler/core/parse.y:6963:12
#11 0x60b5dec0ace6 in main mruby-66606f71d/mrbgems/mruby-bin-mruby/tools/mruby/mruby.c:353:11
#12 0x7cb4e20a91c9 in __libc_start_call_main csu/../sysdeps/nptl/libc_start_call_main.h:58:16
#13 0x7cb4e20a928a in __libc_start_main csu/../csu/libc-start.c:360:3
#14 0x60b5deb30954 in _start (mruby+0xc3954) (BuildId: 0c748cfb61c0f80c654d51d81762fc9c22a26732)
SUMMARY: AddressSanitizer: heap-buffer-overflow mruby-66606f71d/src/vm.c:2790:27 in mrb_vm_exec
Shadow bytes around the buggy address:
0x503000000080: 00 fa fa fa 00 00 00 fa fa fa 00 00 00 fa fa fa
0x503000000100: 00 00 00 fa fa fa 00 00 00 fa fa fa 00 00 00 fa
0x503000000180: fa fa 00 00 00 fa fa fa 00 00 00 fa fa fa 00 00
0x503000000200: 00 fa fa fa 00 00 00 fa fa fa 00 00 00 fa fa fa
0x503000000280: 00 00 00 fa fa fa 00 00 00 fa fa fa 00 00 00 fa
=>0x503000000300: fa fa 00 00 00 01 fa fa 00 00 00 00[fa]fa 00 00
0x503000000380: 00 fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x503000000400: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x503000000480: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x503000000500: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
0x503000000580: 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
==556970==ABORTING
Environment
Expected behavior